Endodontics Flashcards

Question

What are the limitations for a sensibility test?

Answer 1

``` Can't differentiate between: “alive & healthy” “alive and diseased” “alive but just about to snuff it” or “in the process of dying ```

Answer 2

Vitality: blood supply present in tissue Sensibility: ability to respond to a stimuli Sensitivity: responsiveness to a stimuli

Answer 3

Measures BF Uses He neon laser beam directed onto tooth Light contacts a moving object, is Doppler shifted and a signal is produced. As red blood cells are the majority of moving objects, signal measures flow rate of blood

Answer 4

The pulse oximeter sensor consists of two light‐emitting diodes, one to transmit red light (640 nm) and the other to transmit infrared light (940 nm) and a photodetector on the opposite side of the vascular bed. The light‐emitting diode transmits red infrared light through a vascular bed such as the finger or ear. Oxygenated hemoglobin and deoxygenated hemoglobin absorb different amounts of red infrared light. The pulsatile change in the blood volume causes periodic changes in the amount of red infrared light absorbed by the vascular bed before reaching the photodetector. The relationship between the pulsatile change in the absorption of red light and the pulsatile change in the absorption of infrared light is analyzed by the pulse oximeter to determine the saturation of arterial blood.

Answer 5

Thermal and electrical tests assess whether the pulp nerve fibres can respond to a stimulus when applied to the tooth, hence they are sensibility tests

Answer 6

Thermal and electric pulp tests are NOT sensitivity tests, although they can be used to test the sensitivity of a tooth

Answer 7

``` Simple Objective Standardised Reproducible Inexpensive Non‐painful Non‐injurious Accurate ```

Answer 8

Diagnosing pulpal and periradicular symptoms is extremely difficult because the histopathological condition of the pulp cannot be determined by clinical means

Answer 9

Sensibility tests are used to try and reproduce the pain the patient is having & so confirm the source and reason for the pain Tooth localisation

Answer 10

Hundreds of sensory trigeminal afferent axons enter through the apical foramen & branch through the pulp following the distribution of the pulpal blood supply. Ultimately reaching coronal dentine where the plexus of Rashkow is formed Here they terminate as free nerve endings that synapse onto and into the odontoblast cell layer

Answer 11

aim to stimulate the A‐delta (Aδ) +/‐ C fibres Due to the location of the C fibres & their stimulation threshold, it is easier to stimulate the A‐delta fibres

Answer 12

Proposed pulpal pain results when A‐delta nociceptors are activated by fluid movement within patent dentine tubules Hence, for this to elicit pain, odontoblasts must be intact – i.e. pulp is alive Gives indirect information on the pulp status a positive response does not guarantee a healthy pulp It only tests if A‐δ nerves can respond to a stimulus

Answer 13

Use control teeth Use the information from the history, clinical examination and findings, other special tests/investigations

Answer 14

When a patient has unlocalised or referred dental pain To aid in diagnosis between odontogenic and non‐odontogenic pain To confirm apparent radiographic periradicular pathology in the absence of any clinical signs/symptoms To confirm pulpal status when there are clinical signs/symptoms but no apparent radiographic changes periradicularly To discern between a periodontal abscess and an endodontic abscess & help confirm when a perio‐endo lesion is suspected To assess the pulpal status of a tooth prior to crowning. Monitoring the success of pulp caps/ pulpotomies (ensuring that the pulp has not become necrotic) Monitoring traumatised teeth/ revascularization cases (usually over several months). Monitoring teeth following orthognathic surgery/ OS procedures/ facial fractures/ tooth transplantation To confirm profound pulpal anaesthesia.

Answer 15

Electric pulp testers DO NOT interfere with pacemakers

Answer 16

Thermal | Electrical

Answer 17

``` Ice sticks (not could enough) Ethyl Chloride EndoIce (TFE) EndoFrost (PBM) Dry Ice (very rapid sensory response) ```

Answer 18

Superior to Hot test Colder the test more reliable Cold stim causes a rapid outward flow of dentinal fluid: - test a delta fibres, respond to fluid movement, info extrapolated to consider pulp is vital

Answer 19

Warm Gutta percha (place vaseline first) Warmed instrument Electrical heat sources Rubber prophy cup (frictional heat)

Answer 20

``` Less useful than cold Initially stims A delta fibres Prolonged heat stims C fibres Excessive heat can cause pulpal damage An exaggerated and linegring response to heat is indicative of pulpitis ```

Answer 21

A battery operated device passes a small electrical current along the enamel prisms & dentinal tubules to pulp tissue Current causes an ionic shift across the neural membrane inciting an action potential at the nodes of Ranvier in myelinated nerves This stimulates the A‐delta fibres EPTs have a rheostat showing the relative amount of current applied on various scales

Answer 22

``` Explain test and why it's necessary Patient will feel cold Isolate and dry tooth Find a control tooth Tweezers and cotton wool Spray cold stim onto wool and place onto tooth ```

Answer 23

``` On sound tooth structure Incisal edge or incisal 1/3 anteriors Mid third buccal surface premolars Mesio‐buccal cusp tip molars Hold pellet in place until the patient feels the stimuli or for a few seconds if no response ```

Answer 24

A sharp, sharp cold/pain sensation which | immediately ceases when the stimuli removed

Answer 25

A severe, prolonged, exaggerated response to cold

Answer 26

Pulp necrosis Previous pulpotomy or previous pulpectomy False negative

Answer 27

Explain procedure and why it is necessary Patient may feel tinge or warm sensation Dry and isolate tooth + control tooth Place interprox celluloid strip where required Place conducting interface medium on tooth Place tip of EPT on conducting medium and patient completes circuit by earling the lip clip or touching the probe Increase current slowly Let patient respond at pre-pain sensation

Answer 28

On sound tooth structure Incisal edge or incisal 1/3 anteriors Mid third buccal surface premolars Mesio‐buccal cusp tip molars

Answer 29

Sharp warm/hot/tingle or throbbing sensation which immediately ceases when stimulus removed

Answer 30

A severe prolonged exaggerated response

Answer 31

Pulp necrosis Previous pulpotomy or previous pulpectomy False negative

Answer 32

Anxious or young patient | Multirooted tooth

Answer 33

``` Incomplete root development Traumatised tooth Orthodontic tooth movement Heavily restored Pulpal obliteration Periodontal disease (decreased intensity of pain response to cold) Pre-medications Psychosis ```

Answer 34

Improper use/technique

Answer 35

``` Improper use/technique Pus in canal, as it can conduct to periapical tissues Metal splints Bridges Ortho arch wires ```

Answer 36

Proportion of positives correctly identified

Answer 37

Proportion of negatives correctly identified

Answer 38

Develop near the tips of root (where canal communicates with periodontium via apical foramen)

Answer 39

Emerge at other anatomical or iatrogenic openings: - lateral aspects of root - furcations of multirooted teeth

Answer 40

Following pulp tissue breakdown and the emergence of root canal infection Can be symptomatic or asymptomatic Bone resorption part of process

Answer 41

Eliminate bacteria via RCT: - active inflammatory lesion subsides - bone regeneration takes place

Answer 42

``` Macrophages: - HLA-DR+ cells - CD14+ Dendritic: - HLA-DR+ - CD83+ ```

Answer 43

Regulate specific immune responses | - initial phases of apical periodontitis

Answer 44

Antigen specific T cells are cloned in regional lymph nodes - travel to lesion site - become dominant in lesion More CD4 cells than CD8 cells

Answer 45

More CD8 than CD4 Suggests that CD4 are active during the expansion of the inflamm process Involved with bone-resorptive process by activating macrophages producing bone resorbing mediators

Answer 46

Apical granuloma Apical abscess Apical cyst Clinically and radiographically these histopathological entities cannot be distinguished from each other or recognized

Answer 47

Consists of an inflammatory lesion dominated by: - Lymphocytes, - Macrophages and - Plasma cells Numerous fibroblasts and connective tissue fibres usually present - + many capillaries. Around the edge an encapsulation attempt may often be found The epithelium originates from the epithelial cell rests of Malassez Influenced by cytokines & growth factors released in the inflammatory process the normally resting cells divide and migrate. - They may form more or less continuous - Random course - May also become attached to the root surface Polymorphonuclear leukocytes are found in varying numbers Abscess formation can be a transient or persistent event within an existing apical granuloma

Answer 48

Pus within the lesion Abscess formation = cellular dynamics within apical granuloma or direct outcome of an acute primary infection High influx of PMNs (with high phagocytic activity of PMNs) PMNs die and release tissue-destructive elements CT are degraded Tissue in centre of lesion liquefied COntinuum exists between apical abscesses and apical granulomas

Answer 49

``` Epithelium-lined cavity Contains fluid or semi-solid material Surrounded by CT: - infiltrated by mononuclear leukocytes and PMNs - cavity lined with stratified squamous epithelium - originates from epithelial rest of Malassez - can be lined with ciliary epithelium Lining can be be: - continuous - disrupted - completely missing Some cysts never become steady (consume bone or slowly expand) ```

Answer 50

Pocket and True

Answer 51

Located within the periapical granuloma No apparent connection between their cavity and that of the root canal space.

Answer 52

An apical inflammatory cyst Contains a sac‐like, epithelium‐lined cavity Open to and continuous with the root canal space.

Answer 53

The crystals are thought to derive from disintegrating red blood cells in stagnant vessels of the lesion. But could be from inflammatory cells and/or circulating plasma lipids

Answer 54

Assumes that epithelial proliferation results in an epithelial mass that is too large for nutrients to reach its core, resulting in necrosis and liquefaction of the cells in the center. PMNs are attracted by the necrotic material, which, together with tissue exudate, result in microcavities that eventually coalesce to form the cystic cavity

Answer 55

Assumes that tissue liquefaction occurs first, at the central part of an abscess. The peripheral aspect of the cavity is later lined by proliferating epithelium, owing to the inherent nature of epithelial cells to cover exposed connective tissue surfaces

Answer 56

Increased osmosis leading to passage of fluid from the surrounding tissue into the cyst lumen is likely to occur owing to breakdown of epithelial and inflammatory cells Release of bone‐ resorbing factors from mononuclear leukocytes present in the cyst wall, including interleukins, mast cell tryptase and prostaglandins.

Answer 57

Most AP is due to microorganisms within the RC. Other occasional causes include trauma, occlusal trauma, foreign body reaction Bacteria in infected necrotic pulps predominately obligate anaerobes. Different microorganisms display differing ability to survive in the root canal system More likely that a community of microbes exists Biofilms form in RCs. Biofilms protect bacteria from being destroyed

Answer 58

``` Carious lesions Cracks Traumatic exposure Accessory canals Exposed dentinal tubules Periodontal pockets to the apical foramen ```

Answer 59

Nutrition Oxygen Microbial interactions

Answer 60

``` - Spirochetes • Fusobacteria • Actinobacteria • Firmicutes • Proteobacteria • Bacteriodetes No more than 10 per canal and more are negative and are mostly anaerobic ```

Answer 61

Microbes remaining within the canal system

Answer 62

Possesses a “proton pump” which allows it to survive in high pH (i.e. can survive calcium hydroxide) • Can survive in mono‐infection • can survive long periods of low/no nutrition

Answer 63

Periapical cysts – 15% of lesions (Nair 1996) • Serial sectioning indicates two types – true cysts and pocket cysts • Foreign Body Reactions • Cholesterol Clefts

Answer 64

``` neuropeptides, • fibrinolytic peptides, • kinins, • complement fragments, • vasoactive amines, • lysosomal enzymes, • arachidonic acid metabolites, • and various cytokines ```

Answer 65

This activates intrinsic and extrinsic coagulation pathways. • Contact between the Hageman factor and: • collagen of basement membranes, • enzymes such as kallikrein or plasmin, • endotoxins from inflamed root canals can activate the clotting cascade and the fibrinolytic system. • Fibrinogen molecules and fibrin degradation products are released during fibrin proteolysis by plasmin these release fibrinopeptides • Trauma to the periapical tissues during RCT can also activate the kinin system • This will then activate the complement system. • C3 complement fragments found in periradicular lesions. • Products released from the activated systems contribute to the inflammatory process and cause swelling, pain, and tissue destruction.

Answer 66

Mast cells are normal components of connective tissues • present in a normal PDL. • also found within periradicular lesions. • (Physical or chemical) injury causes the release of vasoactive amines • e.g. histamine, which are chemotactic for leukocytes and macrophages. • In addition, lysosomal enzymes cause cleavage of C5 and generation of C5a, a potent chemotactic component, and liberation of active bradykinin from plasma kininogen • Periradicular lesions show increased levels of lysosomal hydrolytic arylsulfatase A and B compared to normal tissues. • Significant levels of PGE2 and leukotriene B4 are also present in these lesions.

Answer 67

PGE2, prostaglandin F2a | (PGF2a), and 6‐keto‐PGF1a

Answer 68

Bacterial antigens come from the infected root canal • taken by antigen presenting cells (APC), • processed and • presented to the T‐lymphocytes (T). • A dual signal of antigen presentation with IL‐1 activates the T‐lymphocytes. • Cytokines produced by these activated cells include • (a) IL‐4, IL‐5 and IL‐6, which induce proliferation and maturation of a specific clone of B‐lymphocytes (B) that were exposed to this specific antigen, to result in plasma cells producing IgG specific to this antigen; • (b) INFγ which serves to activate macrophages which in turn will produce the IL‐1 essential for local recruitment of circulating PMNs and IL‐8 which activates these PMNs. Bacterial endotoxin derived from Gram‐negative bacteria, activates macrophages. • All the above is aimed to allow effective specific phagocytosis by the PMNs of any bacterium emerging from the apical foramen. • Bone resorption is a side‐effect of the defensive process, mediated by TNFβ, produced by the activated T‐lymphocytes and IL‐1β, produced by the activated macrophages. Both activate osteoclastic bone resorption

Answer 69

IL‐1β (mainly produced by activated macrophages) and | • TNFβ(mainly produced by activated T‐lymphocytes

Answer 70

Rarely be able to survive and establish themselves in the apical lesion • In the process of pulpal breakdown, eg after carious exposure, bacteria will gradually gain terrain and move their front line towards the apex, depending on how effective the host response is in limiting further bacterial colonization in the pulp tissue. • The host tissue–bacterial front will be established in the vicinity of or at the exit of the apical foramen. • exact position of the bacterial front is unpredictable. • Can often be well inside the apical foramen, • PMNs engaged in phagocytic activities prevent dispersion of bacterial elements from the root canal biofilm. • Yet, PMNs have a hard time dealing with those organisms attached in a biofilm structure. • this means that there is a constant battle between the spreading organisms and the host defense

Answer 71

Bacteria in chronic abscesses | Bacterial cluster formation?

Answer 72

with a persistent sinus tract. • Viable bacteria can usually be isolated from the exudate • The source may be bacteria that emerged from the root canal space

Answer 73

Actinomyces israeli • Propionibacterium propionicum can grow in clumps and thereby prevail • Such aggregations may become too large for phagocytosis. • bacterial cells are out of reach for phagocytosis = chronic infection • cannot be managed by endodontic treatment

Answer 74

``` comfortable to the patient • not tender to percussion or occlusal pressure • not sensitive to palpation. • Free from sinus tracts • Free from swelling • Has no painful symptoms. • Has normal pocket‐probing depths: • pocketing may also imply a sinus tract drainage along the periodontal ligament space. ```

Answer 75

asymptomatic apical periodontitis (chronic apical/periradicular periodontitis), • symptomatic apical periodontitis (acute apical/periradicular peri‐ odontitis), • acute apical abscess (acute periradicular abscess), • chronic apical abscess (chronic periradicular abscess, suppurative apical/periradicular periodontitis), • condensing osteitis (focal sclerosing osteomyelitis, periradicular osteosclerosis, sclerosing osteitis, sclerotic bone).

Answer 76

unbroken lamina dura • distinct periodontal ligament space of normal width, comparable to adjacent and contralateral teeth.

Answer 77

is longstanding periapical inflammatory • Has radiographically visible periapical bone resorption • has no clinical signs and symptoms. • Is associated with a tooth with a non‐vital pulp (untreated or treated). It might be suspected from a carefully taken disease history in cases when patient has experienced a prior painful event.

Answer 78

Symptomatic apical periodontitis may develop as a direct consequence of the breakdown and infection of the pulp within a previously healthy periapical region. • It reflects a response to an initial exposure of the periapical periodontium to bacteria • or their products emerging from the infected root canal. • may also appear in a tooth with previous asymptomatic apical periodontitis. • Can be a natural shift in the balance previously established between the bacteria and the host or occur in response to endodontic treatment (endodontic flare‐up). • The typical symptoms include: • pain (aching) • may become severe or even unbearable. • usually tender to percussion • mucosa and bone overlying the apical area sensitive to palpation. • premature occlusion

Answer 79

Characterized by: • rapid onset, • spontaneous pain, • tenderness of the tooth to pressure, • pus formation • swelling of associated tissues. • Initially, may be extremely painful, (pressure builds up in bone or periodontal space). • Cortical plate may perforate and pus will accumulate under the periosteum producing a most severe painful condition. • Only with the perforation of the periosteum will the pus be able to drain and allow pain to subside. • Then a tender local swelling will appear. • Sometimes, natural drainage will be established within a few days by perforation of the covering tissue. • In other cases, the swelling will remain for some time before it gradually subsides. • Drainage of an apical abscess will take the “path of least resistance” • thickness of overlying bone • Following penetration of the bone and periosteum, drainage will often be visible: • in the oral cavity but it may also occur • into perioral tissues or • into the maxillary sinus.

Answer 80

Typical feature = sinus tract. • Drains into: • mouth or • extraorally through the skin • A sinus tract may establish exit with drainage • into the gingival sulcus, • in a periodontal pocket or • in a furcation area • MUST be differentiated from periodontal disease and from a pocket associated with a vertical root fracture. • A sinus tract may also lead into the maxillary sinus and cause unilateral chronic sinusitis! • Most commonly associated with an apical radiolucency (but not always) • It is asymptomatic (or only slightly symptomatic) • patient often unaware of its presence. • This may last as long as the sinus tract is not obstructed.

Answer 81

symptomatic edematous inflammation • associated with diffuse spreading of invasive micro‐organisms through connective tissue and fascial planes. • Its main clinical feature is diffuse swelling of facial or cervical tissues. • Cellulitis usually follows an apical abscess that penetrated the bone, • allows the spread of pus along paths of least resistance. • Spreading infection may or may not be associated with systemic symptoms such as fever and malaise. • Since cellulitis is usually a sequela of an uncontrolled apical abscess, other clinical features typical of an apical abscess are also expected. • Spreading of an infection into adjacent and more remote connective tissue compartments may, rarely, result in serious or even life‐threatening complications. • Cases of Ludwig’s angina • orbital cellulitis • cavernous sinus thrombosis • and even death from a brain abscess • originating from a spreading dental infection have been reported.

Answer 82

diffuse radiopaque lesion • believed to represent a localized bone reaction to a low‐ grade inflammatory stimulus • usually seen at an apex of a tooth (or its extraction site) in which there has been a longstanding pulp disease. • It is characterized by overproduction of bone in the periapical area, mostly around the apices of mandibular molars and premolars that had long standing chronic pulpitis. • The pulp of the involved tooth may be vital and chronically inflamed or may have become necrotic with time, leaving the radiopaque area. • Normally the condition does not prompt treatment • unless the pulp necrosis. • The radiopacity may or may not disappear after endodontic treatment or tooth extraction

Answer 83

Natural communications | Pathological and iatrogenic communications

Answer 84

Dentinal tubules Apical foramen Accessory canals

Answer 85

Developmental Disease Periodontal surgery Traumatic injury

Answer 86

I: cementum over enamel II: edge edge cementum and enamel III: gap between cementum and enamel IV: enamel over cementum

Answer 87

Principle route of communication between pulp and periodontium Pulpal inflamm can cause a localised inflammatory reaction May be exposed due to severe loss of attachment

Answer 88

Found apically COntains CT and BVs Don't extend full width of dentine

Answer 89

All teeth with furcation involvement can potentially have exposed furcal canals Lesions suggested radiographically may be due to infectious products from a necrotic pulp diffusing down a furcal or lateral canal

Answer 90

Sensitivity test: - Lower 46,36 (DL root) Upper and lower premolars (1-3 roots) Canines (2 roots)

Answer 91

``` Aggregatibacter actinomycetemcomitans P gingivalis Eikenella Fusobacterium P intermedia Treponema denticola ```

Answer 92

``` Developmental Resorptive lesions Perforations Cracks Mucosal fenestrations ```

Answer 93

Palatogingival groove Usually maxillary lateral incisors If epithelial attachment is breached, grooves becomes contaminated Self-sustaining infrabony pocket develops Loss of attachment can quickly extend to apical foramen Difficult to treat as scaling and RSI does not work

Answer 94

``` Injury Stimulus External inflamm resorption internal inflamm resorption Cervical inflamm resorption ```

Answer 95

Associated with increased probing depths and BOP when resorptive process has perforated entirely through the root

Answer 96

Depending on location, may be associated with increased probing depths and BOP Late stages, can interfere with gingival sulcus and result in periodontal abscess

Answer 97

Starts where the Je attaches to the root surface Microbes in the gingival sulcus stimulate and sustain the resorptive process Associated with increased probing depths, gingival swelling and BOP

Answer 98

Caused pathologically by caries/resorption or iatrogenically by procedural errors Present with perio abscess - pain, swelling, pus draining through PDL and with time infrabony pocket developing Acute inflammatory action will occur Closer to gingival sulcus more likelihood of apical migration of gingiva

Answer 99

``` Location: - better in apical 1/3 Bad with advanced perio Time Ability to seal Chance of building new attachment Accessibility of the remaining RCs ```

Answer 100

Horizontal: Pocket formation may occur when fracture out with alveolar bone Cornola 1/3 root fracture Can present with perio abscess or sudden deepening of a perio pocket Vertical: Microbial colonisation of crack space = periodontal inflammation = breakdown of CT and alveolar bone leading to deep infrabony pocket

Answer 101

Take more than 1 x-ray parallax increases yield J shaped radiolucency Can present initially with perio abscess or sudden deepening of periodontal pocket Deep, narrow pocket, pain on biting, abscess and chronic sinus Definitive diagnosis = surgical exploration Hopeless prognosis

Answer 102

Pathological condition characterised by the perforation of the alveolar bone plate and overlying the mucosa by the roots of the teeth Asymptomatic but are PRFs

Answer 103

``` Root prominence Developmental Perio disease Biotype Chronic periradicular pathosis Ortho tooth movement ```

Answer 104

Endodontic Rx Surgery CT graft

Answer 105

Area of fibrosis Areas of mineralisation narrower canals Reparative responses If blood supply through apical foramen remains intact, pulp can withstand insult from perio disease Pulpal necrosis only seen when perio disease advanced that microbes reach apical foramen

Answer 106

RSI can remove cementum and expose dentinal tubules | Pulpal changes seen adjacent foci of inflamm +/- secondary dentine formation

Answer 107

``` Heat application to intact enamel can increase pulp temp between 5-17C causing irreversible pulpitis Frictional heat depends on: - speed - torque - amount of force Cause odontoblast death ```

Answer 108

A patent route to the periodontium Infected root canal system Sufficient virulent microbes to provoke a periodontal response

Answer 109

Lateral canals in an infected/necrotic pulp may cause lateral periodontal lesions rarely

Answer 110

Where the subgingival biofilm reached a lateral canal, the microcirculation was severed, but inflammation of the adjacent pulpal tissue was minimal When the subgingival biofilm reached the apical foramen, the whole pulp became necrotic

Answer 111

Loss of periodontal attachment directly correlated with the presence of endodontic infection Patients have deeper pockets, increased CAL, higher freq of vertical/angular defects Pulpal infections serve as a risk factor in patients prone to periodontitis (other papers say otherwise) Both endo and perio disease is a microbial infection, microbes associated with a necrotic pulp are fewer than the complex biofilm in a deep periodontal pocket Host response with be acute abscess or chronic inflamm response

Answer 112

Insert a GP cine and radiograph | Can drain through the PDL space to the sulcus

Answer 113

``` 5-10C elevations in external root temo can produce damage to PDL Gutta percha increases flow Tip heated to 250-600C External root temp between 8.5-22.1 Ok to use with care ```

Answer 114

``` Dentine and cementum chips Amalgam Root canal filling material Intracanal dressing, sealers and obturation materials Cellulose fibres Leguminous foods Calculus ``` Can cause acute or chronic reaction Multinuc giant cells surround foreign body

Answer 115

Timing and amount of remaining perio support

Answer 116

2017 World Workshop | Periodontitis associated with endodontic lesions

Answer 117

Palpation Percussion pocket probing Mobility Sinus or pus draining through PDL If sinus is present, palpate to see if discharging If so, insert gutta percha cone and radiograph

Answer 118

Special tests To differentiate between perio and endo Sensitivity test Higher false positives in teeth with advanced periodontitis If perio only tooth will respond to sensitivity testing Use 2 tests to increase reliability Test cavities to differentiate between perio and endodontic pathosis Both perio and endo affecting tooth form a perio-endo lesion Characterised by CAL, bone loss and periradicular pathology

Answer 119

``` Hisotry of symptoms History of surgery deep pockets (average root lengths) furcation Pus exuding from deep pockets or swellings ```

Answer 120

``` Gather history and clinical information (endo and perio exam) 2 Sensitivity tests Radiograph periapical Make diagnosis Or further testing ```

Answer 121

Retain tooth Extraction (vertical and horizontal bone loss) Non-surgical endo/perio treat Resection Elim diseased root Visible with fixed prosthesis (high smile line) Buccal recession around implant Consider condition for potential abutment teeth Increased plaque, CAL and caries with RPDs

Answer 122

Endo first and then perio Cementum and intact PDL fibres may persist, can regenerate after perio treatment Perio straight after endo, destroy fibres form long JE

Answer 123

Allows functional retention of a multi-rooted tooth Remove 1 or more roots Use for furcated max molars Always RCT first before resection After treatment, cuspal coverage restoration Important to remove any dentinal overhangs

Answer 124

``` Root fracture Perforation Root caries Root resorption Severe periodontal disease Grade II or III furcation Failed endodontic treatment ```

Answer 125

Medical/physical issues | Fused roots

Answer 126

62-100% success over 5-13 years Resected teeth have better outcome with regular perio maintenance and Fl application 1:1 root:crown ratio is minimum acceptable Long term tooth retention requires 50% bone support Resected for perio better than non-perio

Answer 127

Aims to regenerate lost periodontal structures Deep narrow defects favourable endo first Retract flap, scale, RSI, removal granulation tissue, type defect, bone graft and resorbable membrane 77.5% success over 5 years

Answer 128

Better for single rooted More success for perio than endo Deep narrow pockets good prognosis

Answer 129

Reaching WL Disinfecting full canal length Keep all RCT material within root canals Dense obturation with no voids within 2mm radiographic apex Having enough dentine to achieve ferrule effect Adequate coronal seal Cuspal coverage

Answer 130

``` CAL Stabilisation of perio disease Reduction of perio pocket depth and lack BOP Effective perio maintenance Presence of furcation Morphology of lesion Sufficient bone ```

Answer 131

Bacteria in the root canal system

Answer 132

Remove/reduce the bacteria to an undetectable level

Answer 133

C&S + NaOCl + one week later Ca(OH)2

Answer 134

Koch's postulates (polymicrobial) Missing the host response Non-cultivable bacteria in root canal (immunocompetence alters response) One bacteria can't cause all these symptoms Due to ecological commensalism (bacterial pairs)

Answer 135

Best amount of healing Overfilled teeth have persistent inflammation Sjorgen: - 0-2 mm 94% - > 2mm 68% - overfilled 76% Aim to fill between 0.5-2mm from the apex of the root

Answer 136

0.5 to 0.65 mm in elderly 0.59 mm 0.72 mm 0.8 mm Apex changes in necrosis cases compared to normal Changes in shape change the apex

Answer 137

``` K K-flex Flexofile Mwo Profile Protaper K3 Hero 642 ```

Answer 138

``` Most common CAn be square, triangular or rhomboidal From 1.97-0.88 sharp grooves per mm 45 helical angle 21, 25 and 31mm length From 6-gauge to the 140th twisted instrument ```

Answer 139

Rhombus stem Remove debris by increasing clearance between file and dentine wall Sharp rhombus angle improve cut efficiency From 6-gauge to the 80-gauge Twisted

Answer 140

Drags large amounts of fabric in its traction cut Helicoidal shape Turned instrument Cut in one direction only, of retraction, due to positive inclination of their groves

Answer 141

Bend to get round corners

Answer 142

Straighten it

Answer 143

A CW rotation greater chance than CCW rotation

Answer 144

Better than straight Less dentine removed Less chance of perforation Better debridement of apical prep

Answer 145

Paper: | - Abou-Rass, Frack and Glick 1978

Answer 146

Determine WL and develop apical stop to #25 Step-back by shortening 30, 35, 40 in 0.5 or 1-2mm increments Recapitulate with #25 Coronal flare with #2 and 3 Gates-Glidden

Answer 147

Passive use #15, 20 and 25 hedstrom in coronal 2/3 of canal system then irrigate Coronal flare with #2 and 3 Gates-Glidden Establish WL and prepare apical seat with standard serial filling Step-back to blend apical and coronal segments Recapitulate

Answer 148

Rotate straight file twice form larger to smaller sequence until 16mm Coronal flare with GG Establish provisional WL 2mm short of apex Rotate stright file at WL Finish apical prep at WL with file 2 sizes larger than first file to reach WL

Answer 149

Use FlexR files or FLexofile for non-cutting pilot tips of triangular file Use crown-down to establish radicular access Rotate straight file CW from 90-180 with light apical pressure to engage dentine Shear dentine by 120 CCW rotation with apical force, flexing it to conform to canal curvature Continue until get adequate apical enlargement at WL Inspect file frew, do not go beyond #35 in curved canals

Answer 150

Passive use larger-smaller files in coronal 2/3 canal system then irrigate Establish WL with small K file. Serial file to prepare apical stop and then step back to blend with coronal step-down flare Circumferentially file with master K file

Answer 151

Establish canal patency with small K file at WL then passive instrument with larger K files Coronal flare with #2, 3 and possibly #4 GG in coronal 1/3 Confirm WL (typically reduced after coronal flare and curvature removal) Increase straight line access with careful re-work with GG Serial file to prepare apical stop and then step back to blend with coronal step-down flare

Answer 152

Used for crown-down sequence Estimate working length from pre-OP radio, subtract 3mm from this length - use this new length to work to for the coronal 2/3 prep Initial negotiation by hand using ISO files 08-20 passive Precurve Use lubricant Take S1/2 to 2/3 canal length turning clockwise until snug then pull from canal and clean If further coronal flare required or relocation orifice use SX to 2/3 Length (WL minun 3mm), turning clockwise Determine WL with apex locator and take ISO 09-20 to WL S1 then S2 to WL turning clockwise as above F1 to length Gauge the size of the apical constriction using a 20K file, if this fits snugly, the prep can be complete at this stage However, generally the apical size needs to be at least 30 to allow irrigation into the apical 1/3 Take F2 to WL and gauge the foramen using a 25 K file If this fits snugly, the prep can be complete Or Take F4 to WL and gauge with 30K file, i fits snugly can be completed Use the same sized paper points for during the canal and same sized GP cone for obturating

Answer 153

150mm bacteria

Answer 154

Martensite heated becomes Austenite and then cools and changes structure, but when deforms reverts back

Answer 155

ISO standard taper (0.4 and 0.6% tapers) Lightspeed system GT system Quantec

Answer 156

``` Active cutting edges Decreased number of instruments needed Asymmetrical cross section Greater cutting efficiency ProTaper Universal K3 Mtwo Hero Shaper iRace and iRace + ```

Answer 157

``` EMphasis on NiTi metallurgy Heating and cooling methods to reduce cyclic fatigue Transition point between martensite and austenite optimised M wire tech R phase tech Twisted files K3 XF files Profile Gt Series X Hyflex CM Flex Files ```

Answer 158

Canal prep more efficient with reciprocation Reciprocation is any repetitive up and down or back and forth motion Liberator Wave One Reciproc Self-adjusting File

Answer 159

Centre of mass or centre of rotation is offset Produces a mechanical wave of motion that transverses along the length of the file Improved cutting and removal of debris by increasing cross-sectional space Reduce engage between file and dentine Revo S ProTaper Next One Shape

Answer 160

Angle of rotation are asymmetrical, CCW and CW

Answer 161

CW rotation greater than CCW rotation CW rotation it will screw in the canal CCW rotation, will unscrew out of the canal CW > CCW, end result is screwing in effect and advancement of instrument Very little pressure necessary to advance

Answer 162

``` Fast Flexible Less transportation and ledging Shapes canal uniformly Reduced operator fatigue Improved efficiency ```

Answer 163

``` CAn't be used in all cases Build up debris NO beyond apical foramen Fracture can occur Cost Loss tactile sensation ```

Answer 164

The practice of various psychological, physical and chemical approaches to the prevention and treatment of preOP, OP and postOP anxiety and pain

Answer 165

``` Anaesthetic agents Inhalation sedation Antianxiety agents IV sedation GA ```

Answer 166

R v B | Risk death

Answer 167

Training R v B Refer necessary

Answer 168

``` Oral sedation Usually Benzodiazepine Augment anaesthetics Pre-Op amnesia Drug choice depend on individual and nature of procedure Should be avoided in CNS depression, sleep apnoea and compromised airway Temazepam* Diazepam ```

Answer 169

``` Numb specific site Provides temp numbing effect on nerve endings on the surface of the oral mucosa Ointment Liquid Spray ```

Answer 170

``` Be non-irritating to the tissues Minimal toxicity Rapid onset Profound Anaesthesia Sufficient duration Completely reversible Sterile ```

Answer 171

Infiltration Block intraligamentary Intraosseous

Answer 172

Less than 30 mins

Answer 173

Less than 60 mins

Answer 174

Greater than 90 minutes

Answer 175

Normal procedures | Preferable for IANB

Answer 176

Profound anaesthesia infiltration | Not IANB

Answer 177

Short anaesthesia, periodontal treatments

Answer 178

Pulpal anesthesia for 10 mins

Answer 179

Comfort COntrol Syringe QuickSleeper Anaeject Ora Star

Answer 180

Accurently manipulate fingertip accuracy and deliver LA with foot control Pen-like grasp, providing greater tactile sensation Flow rate remains constant and can be varied Improved experience

Answer 181

no foot pedal Aids with injection and aspiration controlled directly from syringe No more helpful than a manual syringe

Answer 182

Inflamm changes within the pulp progressively worsen as a carious lesion near the pulp Chronic inflammation is an acute exacerbation Influx of neutro and release inflamm mediators (glandins and IL) Proinflamm neuropeps: - SubP - bradykinin Sensitive the peripheral nociceptors within the pulp

Answer 183

17% mand first molar 11% first premolar 32% lateral incisor

Answer 184

Reduced pH means there is less of the base form of anaesthetic Base form is needed to penetrate the nerve sheath and membrane Less ionised form of LA within nerve to produce anaesthesia

Answer 185

Nerves arise from inflamed tissue have altered resting potentials and reduced thresholds of excitability Not able to prevent the transmission of nerve impulses because of the lowered excitability thresholds of inflamed nerve Presence of anaesthetic resistant Na chs and up reg of Na chls in pulp with irreversible pulpitis

Answer 186

Endodontic: 50-96% | Irreversible pulpitis: 74-96%

Answer 187

Need 27 gauge making through bone with slow speed Immediate onset Distal to tooth as thinnest bone

Answer 188

Must be given under pressure | V painful

Answer 189

71-76% painless treatment vs 46% in placebo

Answer 190

Aids visualisation | Prevents ingestion or aspiration of instruments

Answer 191

``` Rubber dam Punch Forceps Frame Scissors Floss Flat plastic Clamps ```

Answer 192

``` Anxiety management Emergency pulpotomy incision and drainage Extraction Pharmacological pain management Analgesics Antimicrobials ```

Answer 193

As pain and/or swelling, caused by various stages of inflammation or infection of the pulpal and/or periapical tissues

Answer 194

``` Pulpal pain: - irreversible - reversible pulpitis Periradicular pain: - symptomatic radicular periodontitis - acute periapical abscess Cracked/fractured tooth Pain from current endodontic treatment: - NaOCl accident Iatrogenic damage Recent restorations Highly filled teeth Overfilled RC system Root fracture ```

Answer 195

``` No aetiology No caries, trauma, fractures or failing restorations Pain not relieved by La Bilateral or multiple tooth pain Long standing Unresponsive to treatment ```

Answer 196

Burning or electrical pain | Pain increases during different emotional states

Answer 197

Migraine Cluster headache Paroxysmal hemicrania SUNCT

Answer 198

Mod to severe Pulsating Frontotemporal Stress, foods, sleep pattern changes, and hormonal changes

Answer 199

Very Severe Boring Orbital Alcohol and nitrates

Answer 200

V severe Boring Orbital Mechanical

Answer 201

V severe Electric like Orbital Cutaneous

Answer 202

Pain strong clinical emotional quality and must be managed Understanding, sympathy, behaviour tech and pharma if necessary Hypnosis can be useful Greater anxiety = higher painful sensation and decreased pain threshold

Answer 203

Effective for symptomatic irreversible pulpitis Returns for pulpectomy/prep Less challenging that pulpectomy

Answer 204

LA Rubber dam Open pulp chamber and irrigate with NaOCl Amputate coronal stump with slow speed or spoon excavator Don't enter canals yet Irrigate with NaOcl Dry with dampened cotton Seal CaOH into pulp chamber Cover with some cotton covered by Cavit + GIC/RMGIC Give advice Return for RCT

Answer 205

Results in significant reduction in pain within 24hrs in 90% patients

Answer 206

ALters pulp haemodynamic and interstitial tissue pressure, deceases local tissue pressure and decreases inflammatory mediators, severs terminal endings of nociceptors

Answer 207

Non-vital tooth symptomatic PRP Acute periapical abscess Pulpotomy will not relive sufficient pain

Answer 208

Complete pulpal extirpation and debridement of the RCS

Answer 209

Reduces bacterial products in the apical 1/3 of the canals Decreases the nociceptive activity in the periradicular tissue Substantial decrease in pain between 24-36 hrs

Answer 210

Develop from a symptomatic or asymptomatic PRP or a chronic apical abscess

Answer 211

Bacteria that egress infected RCS and invade periradicular tissues to establish an extraradicular infection and evoke purulent inflammation Dom by anaerobic bacteria 12-18 bacteria compared to 7-12 in root canals

Answer 212

``` Pain TTP Tender to palpate buccal sulci +/i mobility, local swelling and facial space involvement Systemic manifestations: - fever, headache and nausea Radiographically: - possible widened periodontal ligament space Sensibility testing Periapical abscess = non-vital tooth Periodontal abscess = vital tooth ```

Answer 213

Through the path of least resistance | Result in local swelling where it exists through the alveolar bone, discharged via the PDL or spread into tissue spaces

Answer 214

Remove source of infection or relieve Pa through drainage Extract Pulpectomy + drain via RCS Incise and drain Exudate can be removed via RCS, can relieve pain

Answer 215

Access to RCS to WL, if no drain, take 08 or 10 K file through apical constriction, can enable drainage If not irrigate and dress as usual DO NOT leave open (can cause delayed healing and later flare ups Can become heavily infected Persistent drain - allow patient to wait 30 mins Dress with CaOH and seal access

Answer 216

Bacteria from RCS enter periradicular tissue and the immune system is unable to suppress invasion, they will eventually show symptoms Can be found in vestibule or into fascial space

Answer 217

Spread into the fascial spaces from the periradicular area of a tooth Spread of purulent exudate

Answer 218

Potential anatomic areas that exist between the fascia and the underlying organs and other tissues

Answer 219

Swelling is fluctuant and in soft tissue

Answer 220

Needs LA Mandible: IANB injection and long buccal injection Maxilla: infiltrate both sides of facial swelling Palatal: infiltrate over the greater palatine foramen or nasopalatine foramen If abscess over foramen, infiltrate on either side

Answer 221

SPread infection Painful Increased BF, removes drug quicker

Answer 222

Potential space between the mylohyoid muscle superior and platysma inferiorly Molar tooth

Answer 223

Submental Sublingual Submandibular Can advance into pharyngeal and cervical spaces

Answer 224

Potential bilateral anatomic area of the chin that lies between the mentalis muscle superior and platysma inferior Anterior tooth

Answer 225

Anatomic area between the buccal cortical plate, overlying the alveolar mucosa and the buccinator muscle (post) or the mentalis muscle (ant) Mand posterior or anterior tooth

Answer 226

Potential anatomic area between mylohyoid muscle superior and platysma inferior Anterior tooth

Answer 227

Anatomic area between the buccal cortical plate, overlying mucosa, and the buccinator (post) or mentalis (ant) Mand post or ant tooth

Answer 228

Area between the buccal cortical plate, overlying mucosa and buccinator Max posterior

Answer 229

Between lateral surface of buccinator and medial surface of skin of cheek Posterior mandibular or Maxillary tooth

Answer 230

Space between the lateral surface of the medial pterygoid and the medial surface of the ramus Mand second or third molar

Answer 231

Space between levator anguli inferior and levator labii superior Max canine or first premolar Midface infection can cause cavernous sinus thrombosis

Answer 232

Max central incisor

Answer 233

Max teeth | Lateral incisors

Answer 234

Life threatening cellulitis advance into pharyngeal and cervical spaces resulting in airway obstruction

Answer 235

``` Antibiotics + endodontic treatment Aggressive incision for drainage Relieve Pa Extraction RCT Incision/drainage ```

Answer 236

Decompression of increased pressure associated with oedema Pain relief Improves circulation to area, allowing better delivery Extraoral drain may be required

Answer 237

Phago kill bacteria Leukocytes influx stop Neutrophilic leuko die of apoptosis Macro clean up mess

Answer 238

As pulpal pain is due to inflammation, they are good anti-inflammatories

Answer 239

Affect prostaglandin synthesis Inhibit inflamm mediators Suppress release of mediators at site of noxious stim Decrease peripheral nociceptor sensitisation

Answer 240

``` Ceiling to their analgesic effect Ulcers Asthma Liver dysfunction Diabetes Gout Influenza (Reyes syndrome) ```

Answer 241

Contra for NSAIDs Post-endo pain Analgesic and Antipyretic

Answer 242

Overdose | Acute liver failure

Answer 243

Enhances the analgesic effect Paracetamol appear to selectively converted within the brain into another drug which block PG synthesis in the brain having an analgesic effect on the CNS and NSAIDs act on PNS

Answer 244

No difference in pain control compared to placebo: - post-OP pain - swelling - flare up - analgesic consumption

Answer 245

``` Pulpal necrosis: plus - diffuse swelling - drainage can't be achieved - systemic involvement - fever, malaise, trismus or lymphadenopathy Needed for RCT with post ```

Answer 246

``` Check for sharp bites and normal biting feel Usual LA advise Injection site may be tender Gingiva sore or bleeding Tooth to be tender ```

Answer 247

``` Extrusion of irrigant into periradicular tissue Occur when: - needle wedges in canal - tooth wide open foramen - immature apex - resorbed apex ```

Answer 248

``` Sudden, prolonged sharp pain Rapid and diffuse swelling Hemorrhagic reaction Oedema Bruising Tissue necrosis ```

Answer 249

Iatrogenic by error Blood seen during RCT Acute inflammatory reaction will occur Present with perio abscess (pain, swelling and pus draining via PDL)

Answer 250

``` Acute exacerbation Significant increase in pain and swelling Sudden exacerbation of a previously symptomless periradicular lesion Need emergency appointment Low occurrence Need active treatment Irrigate canals Drain Pre-emptive analgesia can be successful ```

Answer 251

``` Apical debris extrusion Incomplete instrumentation Secondary intracanal infection Lost provisional restorations Non-microbial causes ```

Answer 252

``` Gender Systemic disease Diabetes Pre-Op pain Tooth type (5,6,7) Necrotic teeth ```

Answer 253

``` Pre-emptive analgesia Rubber dam Crown down sequence Achieve WL and irrigate passively Clear post-OP instructions ```

Answer 254

``` Analgesics Check canals Ensure correct WL Irrigate to apical 1/3 Drainage via RCS SWelling present, consider incision and drainage Irrigate a lot Redress with CaOH + GIC Check occlusion ```

Answer 255

``` Over-instrument Overfill Irritated periradicular tissue Perforation Root fractures Cold lateral compaction Restoration in supraocclusion Poor occlusion ```

Answer 256

Remove cause: - defective filling - caries

Answer 257

Emergency pulpotomy Pulpectomy extraction

Answer 258

Pulpectomy | Extraction

Answer 259

Pulpectomy and drainage via RCS Incision and drain via ST Extraction Antibiotics if systemic

Answer 260

Patient wants to keep the tooth but only if its restorable Tooth restorable Prevent denture Pulp in the abutment for a bridge has irreversible damaged or non-vital

Answer 261

TO check for: - routes of microbial ingress (caries, cracks and defective margins) - quality and quantity of dentine remaining - investigate the tooth

Answer 262

Remove all caries and defective restorations Restore Radiographs: - needs 2-3mm of periradicular tissue Remember to consider the status of adjacent and opposing teeth

Answer 263

Perio status General factors Prosthodontic prognosis (seal) Endodontic prognosis

Answer 264

Cooperation Anxiety Staying still

Answer 265

``` RA Diabetes Coronary Heart DIsease Radiotherapy HIV ```

Answer 266

Higher prevalence of periradicular periodontitis Slower healing 2 x risk for flare ups Outcome for treatment worse

Answer 267

``` Rubber dam Chlorhexidine NaOCl ZnOE Resins Gutta percha ```

Answer 268

``` Complexity Sinus involvement Previous RCT WL Isolation Obturation dense + requirements Coronal seal ```

Answer 269

``` Pulp chamber Root canals visible Root curvature Root length Apical closure Previous RCT Restoration Location and Position ```

Answer 270

Size decreases with age and due to secondary/3rd dentine Smaller chamber is more difficult increased iatrogenic errors Calcification can impede access into RCS

Answer 271

Occurs with increased age and 2nd/3rd dentine deposits In response to trauma Radiolucency = canal If RCS not present, RCT not really possible

Answer 272

Curves or SH shaped curve, increase risk of file mishaps such as breaking or perforations

Answer 273

Can cause open apex Idiopathic root resorption Need sufficient working length Can be longer than expected

Answer 274

Tilted, rotated and retroclined can make access difficult

Answer 275

Open apex is the sequelae of an injury during root development which has caused pulpal necrosis Root fails to form Root resorption can occur XLA due to deep occlusal caries

Answer 276

Access to apical 1/3 | Difficult to tell the material

Answer 277

Best V good Slightly reduced Lowest

Answer 278

Mainly to apical healing and is the measure traditionally used by endodontists

Answer 279

Mainly to functionality of the tooth

Answer 280

``` Lack signs and symptoms No history of pain/discomfort Not TTP Not tender No sinus or swelling Radiographic healing Functional and aesthetic ```

Answer 281

97% functional at 8 years after initial non-surgical management

Answer 282

Limited access unrestorable tooth Long term functionless or non-strategic tooth Severe, progressive perio disease Patient can't lie supine or still for long enough If too difficult REFER

Answer 283

``` Presence of periodontitis BOP OH Caries LoA Pockets Furcations Bone support Unusual anatomy Restoration margins (caries/fracture extending subgingivally) If tooth margin below gingiva - crown lengthening ```

Answer 284

``` Dentogingival attachment to the tooth Epithelium + CT = 20.4mm JE 0.97mm ACJ 1.07mm BW greater for posterior teeth Range between 0.75-4.33mm ```

Answer 285

Exhibits 2 conditions concurrently Marginal LoA Periradicular periodontitis (PRP)

Answer 286

Tooth have noth advanced perio disease and coincidentally develop pulpal necrosis + PRP at the same time Tooth with advanced perio disease + LoA extending the apical foramen (causing pulpal necrosis and develop PRP) A tooth develop necrotic pulp + PRP, infection can cause perio pocket

Answer 287

Quantity and quality of remaining tooth structure Need at least 2mm supragingival dentine around the circumference of the tooth Remaining coronal tooth substance offers retention, resistance, a substrate to bond to and the ferrule effect

Answer 288

A metal ring or cap intended to embrace the tooth structure cervically to achieve root strengthening and prevent shattering the root 2mm H 1mm W

Answer 289

Exposed dentine offers route for microbial ingress to pulp Can cause pulpal inflammation If slow, tertiary dentine formed quick enough If fast, can endanger pulp Either through exposure or loss of vitality, pulp becomes necrotic But don't have complications after RCT treatment

Answer 290

``` Location in arch Molars/teeth involved in guidance have higher loads # of teeth present Tooth in function Parafunctional habits Repeated resto to tooth Mobility ```

Answer 291

Dentition with an intact anterior region and a reduction of occluding pairs of post teeth Molars not replaced

Answer 292

Quality of the coronal restoration at preventing microbes from gaining access to the RCS Seal fail = RCT fail Filling/Crown/Bridge

Answer 293

``` Resorption defects Pulp stones Calcified canals Curved canals Curved apices Restorations difficult to remove Previous RCT Procedural errors ```

Answer 294

Anatomy of the pulp chamber

Answer 295

1. Diagnosis 2. Assess restorability and study radiographs 3. Plan access 4. Dam 5. Magnification

Answer 296

1 oval shaped canal so the outline of the access cavity is an oval

Answer 297

2 canals, may be connected by an isthmus Gives a figure of 8 type shape Outline form of access should reflect the figure of 8 shape Oval like shape

Answer 298

3 canals Outline form of access cavity reflects where you expect to find these within the pulp chamber Rhombus like shape

Answer 299

``` Prevent coronal leakage during RCT Create reservoir for irrigation Good retention and thickness for temp resto Locate all canal entrances All seen from one view Give straight line access to apical 1/3 Remove all pulp chamber roof and coronal pulp tissues Conserve as much dentine as possible ```

Answer 300

Parallel periapical

Answer 301

``` Remove all caries and defective restos and replace Assess restorability Consider removal of extracoronal restos Plan shape and location of access LA Magnification Dam ```

Answer 302

1. Remove caries 2. Assess restorability 3. Allow isolation for treatment 4. Maintain occlusal relationship 5. Maintain apperance

Answer 303

Place the vaseline covered spreader into pulp and restore around it then remove to create an access to the remaining pulp

Answer 304

Compromised visibility: - canal location - caries Porcelain may fracture

Answer 305

True orientation of the remaining tooth Lead to perforations Loss of support for the crown

Answer 306

Lingually | To achieve straight line access whilst reducing aesthetic and restorative concerns

Answer 307

Occasionally | To achieve straight line access whilst reducing aesthetic and restorative concerns

Answer 308

Failure to remove all the pulpal debris from the chamber | Increases chance of perforation

Answer 309

of second mesiobuccal canals in max molar increased from 51-82%

Answer 310

Safe ended/non-cutting burs | Endo Z bur

Answer 311

Long fissure bur for initial outline form One the root of the pulp chamber is entered Non-cutting/safe ended tip bur

Answer 312

Age | Previous trauma

Answer 313

Always at the CEJ In the centre of the tooth Measure before you start on the external surface Check depth when creating the access cavity Bur tends to drop into pulp chamber

Answer 314

Rubber dam | Cavity can be refined later

Answer 315

Ensure a seal is made Use caulk Then irrigate pulp chamber with NaOCl If pulp is vital, haemorrhage will stain the dentinal tubules, if not removed immediately

Answer 316

Small, delicate adjustments Pulp chamber is not all that deep, composite finishing burs can be used OR endodontic ultrasonic Confirm canal entrances using a DG16 endodontic probe

Answer 317

Irrigated lots with NaOCl Remove pulpal remnants and dentine chips Bleach floor of pulp chamber enhancing vision of the canal orifices

Answer 318

``` Wrong tooth Can't locate canals (not in correct place) Create false canals Make it harder to find actual canals May perforate ```

Answer 319

Pulpal debris is not removed Files must bend more to get into canals Canals not located

Answer 320

Sacrifices dentine weakening tooth tooth susceptible to irretrievable fracture Files do not slide gently into canal entrance but catch on step

Answer 321

``` NaOCl will bubble over canal entrances Sharp DG16 robe to pick Use dye (methylene blue) Endodontic ultrasonic Long neck or gooseneck burs ```

Answer 322

Eliminate microbial infection VIa chemomechanical preparation and disinfect of the root canal system All root canals must be located

Answer 323

Curved | S shaped

Answer 324

Starts at CEJ or apical to it and extends to the apical foramen Apical foramen is usually within 3mm of the actual root end Lateral.accessory canals are common RCS often ends in a delta

Answer 325

Apical constriction is accepted as being 1mm short of the radiographic apex

Answer 326

A single canal from orifice to foramen

Answer 327

2 canal orifices in chamber but merge and exiting through 1 foramen

Answer 328

2 canal orifices, 2 distinct canals and exit through foramina

Answer 329

1 canal orifice in chamber, divides some way down root into 2 seperate canals and 2 foramina

Answer 330

Maxillary 2nd premolar

Answer 331

``` Round Ribbon Figure of 8 Ovoid Kidney bean C shaped ```

Answer 332

``` RD: 10 Y 1 root 1 canal - TI Lateral/accessory canals common (found in apical 1/3) Pulp chamber: - 3 pulp horns newly erupted - 2 pulp horns mesial and distal - triangular in young - oval in older Access palatally ```

Answer 333

``` RD: 11 Y 1 root: - inclined palatally and distally - round in Xsec - flattened mesio-distal 1 canal: - apical foramen often laterally Lateral canals can occur Pulp chamber: - 0 or 2 pulp horns (mesial-incisal and distal-incisal) Oval shaped canal becoming more circular in the apical 1/3 Variations: - peg lateral - dens in dente - long tubercle in cingulum - dens invaginatus Access palatally ```

Answer 334

``` RD: 13-15 1 long root: - fenestration apically - curve labially in apical 1/3 1 long canal: - may have lateral canals in apical 1/3 - apical foramen often lateral Pulp chamber: - 1 pulp horn Xsec: - oval Access palatally ```

Answer 335

``` RD: 9-10 Y 1 root: - flattened mesiodistally - figure of 8 Xsec - curve distally - T1 canal - can be 2-1 or 1-2-1 - apical foramen lateral Pulp chamber: - 3 pulp horns corresponding to mamelons Xsec canal: - oval coronally Find 2nd canal extend into cingulum 1 foramin Ribbon shaped Access palatally ```

Answer 336

``` RD: 12-14 Y 1 root: - TI canal - some TII (labial and lingual) - lateral canals - mostly apically - apical foramen lateral - apical delta Pulp chamber: - 1 pulp horn Xsec: - oval becoming round apically Access lingual ```

Answer 337

1 (70%) | 2

Answer 338

1 (75%) | 2

Answer 339

1 (78%) | 2 merge into 1

Answer 340

TI TII TIV

Answer 341

``` Diagnosis 1 parallel periapical radiograph Remove caries or defective resto and replace Plan shape and location LA Microscope Dam ```

Answer 342

Dam Matrix band Place petroleum jelly covered finger spreader in each canal orifice

Answer 343

See subtle changes of colour, texture and sclerotic plugs of dentine in the canal orifices Floor of pulp chamber is always darker than walls Identify when you have removed the roof of the pulp chamber Locate extra, small canals

Answer 344

``` Good canal vision Act as a reservoir for irrigants Have no overhangs of the pulp chamber roof Provides support for temporary fillings Aim to always have 4 intact walls Straight line access to canals ```

Answer 345

Long fissure diamont to cut the outline form of the access cavity and penetrate the roof of the pulp chamber Bur drops into chamber Swap to an Endo Z bur and remove the rest of the pulp chamber roof Irrigate the chamber with NaOCl and use spoon excavator to remove any pulpal debris Identify canals using the DG16 or a small ss file (10) Check straight line access into all canals using the DG16 and magnification

Answer 346

Remove any dentinal shelves or bulges: - use slow speed with care - ENdo Z bur - fine grit composite finishing bur - endodontic diamond coated ultrasonic tip

Answer 347

The disappearance of a large canal in a premolar often

Answer 348

Mand - distal | Max - palatal

Answer 349

Removing the roof of the pulp chamber | Use an Endo Z bur to remove

Answer 350

DG16 and 08/10 K file Flood pulp chamber with NaOCl Place a size 10 K file passively in coronal 2/3s of canal Help prevent SS files gouging into canal walls Decreases stress on NiTi files which could lead to fracture

Answer 351

Accessory canal in the furcation region of permanent molars 30% of mand and max molars had accessory canals in the furcation area Prevalent in upper and lower 6s

Answer 352

COnnecting, usually narrow, part, organ or passage especially when joining structures or cavities larger than itself Narrow, ribbon shaped communication between 2 root canals that contain pulp tissues Occur with in any tooth with multiple canals

Answer 353

mechanical cleaning and shaping of an isthmus is difficult and can lead to treatment failure if ineffective If not identified can lead to treatment failure

Answer 354

``` RC: 18-25 3 roots (MB/MP and P - converge) Root curves distally Short in length Variable tooth morpho Can be peg shaped Needs radiograph ```

Answer 355

``` RC: 14-16 3 roots Roots coalescence (MB/DB) 3/4 canals Usually MB (MB2) DB and P Pulp chamber: - 4 horns for 4 cusps DB straight MB curved P largest round/oval and curved apically Access mesially of the occlusal surface ```

Answer 356

``` RC: 9-10 Y 3 roots Palatal root longest and most divergent because of max antrum Buccal root curve distally DB < MB length 4 canals: - MB MB2 DB P Cross sections: - DB round - MB flattened and most curved distally - palatal largest canal Access mesially via occlusal ```

Answer 357

``` RC: 12-14 Y 1 root (can be 2 bifurcation) 1 canal or 2 Pulp chamber: - 2 cusps = 2 horns - buccal pulp hor larger than palatal Xsec: - flattened mesiodistal - oval for 1 canal - isthmi for 2 canals Figure of 8 cross-section Access cavity: - narrow mesiodistally - oval shaped buccolingually ```

Answer 358

``` RC: 12-13 2 roots (buccal and palatal) Roots curve slightly distally 2 pulp horns can have 1-3 roots Buccal root may divide into a MB and DB root Figure of 8 cross-section Access cavity: - narrow mesiodistally - oval shaped buccolingually ```

Answer 359

``` RC: 12-13 1 root: - rounded in Xsec - slight distal curve - root sometimes bifurcated 1 canal Pulp chamber: - 2 pulp horns at different heights - B > L - pulp chamber roof tends to tilt lingually Xsec: - oval shaped - divide buccal and lingual half way down and then re-merges Access cavity oval buccolingually ```

Answer 360

``` RC: 13-14 Y 1 root, curves distally Root may bifurcate Pulp chamber: - 2 pulp horn and a single canal 3 cusp version has 3 horns Xsec: - oval-round Access cavity: - oval buccolingually ```

Answer 361

``` RC: 6-7 Y 2 roots: - mesial flat with mesial groove (figure of 8 cross section) Pulp chamber: 5 cusp - 3 buccal - 2 lingual Xsec: - distal = large oval or 8 figure - mesial root = 2 canals (B and L) connected by isthmus and tend to curve distally - mesial canal can bifurcate Variations: - extra distal root lingually Access cavity: - mesial side of the occlusal surface - if lingually inclined better to move slightly towards buccal and MB cusp ```

Answer 362

``` RC: 14-15 Y 2 roots (M and D) - roots can be fused - extra root in DL 3 root canals: - ML MB and D Pulp chamber: - 4 pulp horns Xsec: - mesial: 8 figure, separate with 2 apical foramina, often have isthmus Variations: - 1 c-shaped canal - may have 2 canals Access cavity towards mesial of occlusal surface ```

Answer 363

``` RC: 18-25 Y 2 roots M & D Shorter roots than other molars Roots may be fused Distal curvature of roots CAn have 3/2/1 canal Access cavity dependent on radiograph ```

Answer 364

4 MB/DB 19-22 P 22-25mm

Answer 365

3 MB/DB 19-22mm P 21-23mm

Answer 366

3 MB/DB 18-22 mm P 18-23mm

Answer 367

3 ML/BM 21mm D 22-23mm

Answer 368

3 | ML/MD/D 20mm

Answer 369

1/2 | 19mm

Answer 370

Variety of sizes • Made by cutting barbs into metal wire blanks • Used for removing vital pulps • Sever the pulp at the apical constriction • Not used so much nowadays (NiTis taken over) • Are very useful for removing small cotton wool pellets from within the root canal system

Answer 371

If pulp is intact (e.g. in a vital or irreversibly inflamed pulp), it may be possible to remove it in 1 piece • Use a ss barbed broach with care • Can get caught on sides of canal • Avoid use in narrow/calcified canals as can # • Where the pulp is necrotic, it is no longer intact and the remaining pulpal debris will be removed during the canal shaping and disinfecting procedures – DO NOT need barbed broach

Answer 372

``` Mirror – front silvered mirror so there is not a double reflection • Locking tweezers Perio probe • DG 16 • Excavator Flat plastic • Burnisher/plugger • measuring block & clean stand ```

Answer 373

K-type | Hedstrom

Answer 374

The ISO size indicates that all ‘ISO‐sized’ instrument have a 2% taper. ISO sized files (e.g. K files, Hedstroms) have a fixed taper • i.e. all the files increase in size by the same amount relative to their tip size. • Over the 16mm length of the cutting flutes, they increase in diameter by 0.32mm • This is a 0.02mm increase in diameter per mm length of the cutting flute... • Also known as a .02 or 2% taper

Answer 375

the amount the file diameter increases each mm along its cutting surface from the tip towards the file handle

Answer 376

Made by twisting square or triangular metal blanks....which means they can untwist! Must check for this during use • Horizontal cutting blades • Non‐cutting tips • In 21mm, 25mm, 31mm lengths • All have a 16mm length of cutting flute • Mainly made in ss but get niti too (e.g. niti‐flex Dentsply) • Use ss for routine ‘guide path’ & for negotiating ledges Files are identified according to their tip size This file is a ‘40’ because at its tip (or D0) the diameter is 0.4mm

Answer 377

Use in a turning/rotation type movement • Either ‘watch‐winding’ or balanced force • NEVER a ‘screw‐in’ movement • V rarely an up‐and‐down movement • Relatively flexible...BUT as size increases, rigidity increases

Answer 378

``` Design has been modified to increase file flexibility changing cross section square to rhomboid from & using more flexible steel eg K Flexofiles • The tip has also been modified: • The tip guides the file and enlarges RCS • If an instrument has a cutting tip it can gouge into the canal walls creating a false canal • Now ‘non‐cutting’ or ‘semi‐ cutting’ tips ```

Answer 379

``` Milled from round ss blanks • DO NOT rotate as can fracture • Designed to be used up and down • Aggressive instruments which can easily damage the root canal • Not recommended for routine use • Use in root canal re‐ treatment to help snag remaining bits of GP ```

Answer 380

Rotary instruments • In the past, used routinely for ‘coronal flare’ • BUT can only be used in straight portions of the canal • Side cutting instruments/ non‐ end cutting tip • Different sizes available If not used carefully GG can remove far too much dentine, weakening tooth and potentially perforating - Superseded by NiTi files

Answer 381

Elbow Zip Ledge Transportation of foramen

Answer 382

``` Blockages • Ledges • Transportation • Elbows • Zips • Perforation • Instrument separation ```

Answer 383

• Caused by dentine debris getting packed into the apical portion of the root • Is extremely hard to remove! • Attempts to remove it can result in a false canal being cut and possible perforation • Avoid by ‘recapitulating’ during canal preparation • Between each file, passively re‐insert an 08 or 10 K‐file to length

Answer 384

A ledge is internal transportation of the canal • Occurs when working short of length with straight files • Avoid by ALWAYS precurving • Ledges can sometimes be bypassed but difficult

Answer 385

Transportation of the apical foramen changes the shape of the foramen • This makes it more difficult to fill/seal & also fails to provide resistance for packing of gutta‐percha • Can easily overfill - Avoid crown-down sequence

Answer 386

The outer side of the curve is over‐ enlarged & the inner side of the curve under‐prepared • Transports the canal • The narrowest part of RCS where zipping has occurred is called an ‘elbow’ • This hour‐glass shape makes satisfactory obturation of the apical third very difficult • Avoid by using ss files only for guide path & then swap to niti’s

Answer 387

Can occur where an end‐cutting file is used, or over zealous preparation of a ‘zipped’ or blocked canal. • A false canal is cut through the radicular dentine and into the periradicular tissues • If this happens during RCT, there will be bleeding into the canal +/‐ patient c/o pain • Radiographs using parallax shift can help identify • Electronic apex locators help identify • Dental operating microscope to identify & repair • Avoid by using non‐end cutting files wherever possible, work passively, never force a file or bur into the RCS

Answer 388

The use of NiTi files has reduced the clinical incidence of blocks, ledges, transportation & perforation • BUT they are believed to # fairly easily • This can create a problem, as a fractured file blocking access to an infected part of the RCS means that necrotic debris cannot be removed and the success of treatment reduced

Answer 389

Torsional fatigue | Flexural fatigue

Answer 390

Occurs when the instrument tip is locked in the canal and the instrument above the jammed/locked portion continues to rotate. This causes it to fracture • This type of fracture is due to too much torque on the file • The torque generated on a file during canal preparation depends on: • The contact area of the file with the walls of the canal • Using a crown‐down approach reduces torque • Using a light pressure on the files reduces torque

Answer 391

Cyclic loading leads to metal fatigue | • As all endodontic files are single use in the UK this is unlikely to happen

Answer 392

Each system tend to vary in design...e.g. tip shape/size, cross section, taper etc • Niti files are milled, although some recent new files twisted (Twisted files by Sybron Endo)

Answer 393

``` Superelasticity - Increased flexibility in larger sizes and tapers - 3 x more than ss • Increased cutting efficiency • Faster preps • Less iatrogenic damage • Stays centered in canal • Less transportation • More predictable result • BUT more expensive ```

Answer 394

Superelasticity with shape memory/recovery | • High resistance to cyclic fatigue

Answer 395

Each instrument has a variable taper along its length • Prevents screw‐in effect • Allows increased apical tapers (Finishing Files) • Allows excellent shaping with few instruments • Each instrument engages a smaller zone of dentine which reduces torsional loads, file fatigue and potential for breakage • Varying tip diameters • Superior flexibility, high efficiency and improved safety • Mostly side cutting files • Consist of a set of either 8 hand files OR 8 rotary files which can be used interchangeably.

Answer 396

``` 3 shaping files - S files: coronal and mid third - SX - S1 - S2 5 finishing files - F files: apical third - F1 - F2 - F3 - F4 - F5 ```

Answer 397

Tip: - Shaping files have partially cutting tips • Finishing files safe, non‐cutting tips Xsec: - shaping files different from the finishing files • Finishing file cross section allows for greater flexibility & for debris to move coronally Taper: - shaping files have tapers which increase coronally • finishing files have tapers which increase apically

Answer 398

``` No coloured band – is ‘gold’ shank • Length 19mm • Tip diameter 0.19mm • Taper apically 3.5% • Taper coronally19% • Can be used before or after S1 and S2 • Creates a large amount of coronal flare • Hand version use by turning clockwise • Rotary version can be used to relocate canal orifices • Use ‘brushing’ motion ```

Answer 399

Rotary ProTapers can be used very effectively to flare canals using a brushing action. • ALWAYS use carefully to avoid over‐preparing/over‐’brushing’ in ‘danger zones’ • Danger zones = the distal surface of mesial & MB roots & mesial surface of distal roots etc (furcation areas)

Answer 400

``` S1 = purple handle • S2 = white handle • Tip diameters • S1= 0.185 • S2= 0.20mm • 14mm cutting flutes • Partially active tips • to guide through debris • Tapers vary along length • increasing from a minimum of 2% at tip to 11.5% at handle‐end • Use hand files by turning clockwise • Rotaries with a ‘brushing’ motion ```

Answer 401

Allows excellent control of speed • Constant low speeds protect against file fracture • High torque control • Warns (by beeping) if the instrument is likely to break • Take it out, clean file, wash canal and check file intact and no plastic deformation prior to reusing • Can set auto reverse

Answer 402

To use rotaries, need… straight line access • Excessive bending will lead to separation • No severe curves • No merging/branching canals • NOT designed for initial canal negotiation (see later) • NOT designed for by‐passing ledges • Oval and ribbon shaped canals • present difficulties for rotaries • Use plenty irrigation!

Answer 403

• ALWAYS create a guide path (to size 20 flexofile file) PRIOR to using any rotaries in the RCS • Canal should ALWAYS be flooded with irrigant prior to taking any files into the canal • Use rotaries at a CONSTANT speed of ~250 rpm with high torque • Use files gently, NEVER push hard/force a file into a canal • NEVER stop and start the motor with the file in the canal • Remove files from the canal frequently & clean flutes on a sponge and irrigate • Be clear on the ‘movement’ the system you are using requires...e.g. ProTaper require ‘brushing’ movements, some other systems require ‘pecking’

Answer 404

Remove infected soft and hard tissue • Microorganisms, toxins, pulpal debris • Allow irrigants access to the apical third for disinfection & removal of the smear layer • Create a smooth tapered shape of the RCS to allow: • Space for medicaments • Space for obturation to the apical constriction • This will seal the RCS along its length and protect against microbial re‐entry • Aims to ‘entomb’ any remaining microbes so they cannot incite an inflammatory response in the periradicular tissues • Retain the integrity of the radicular structure.

Answer 405

``` Mechanical instrumentation • (using hand or rotary files) • Disinfection • (using irrigants) (+/‐ 3. Intracanal medicaments placed between appointments) ```

Answer 406

flush out debris, lubricate the path of instruments for the mechanical shaping, destroy micro‐ organisms & organic matter

Answer 407

Broad antimicrobial spectrum • Highly effective against anaerobic & facultative micro organisms organised in biofilms • Dissolves necrotic pulp remnants • Remain active in the presence of blood, serum & protein derivatives of tissue • Does not stain tooth structure • Inactivate endotoxin • Prevent formation of a smear layer – or dissolve it if it forms • Not affect dentine deleteriously • Retain its effectiveness when mixed with other irrigants • Non toxic & hypoallergenic • Inexpensive

Answer 408

sodium hypochlorite • (Chlorhexidine gluconate) • Iodine compounds

Answer 409

EDTA | • Citric acid

Answer 410

Antibacterial • Broad antimicrobial spectrum • Kills bacteria, yeasts & some viruses • In water NaOCl ionises • Forms hypochlorous acid which releases chlorine • Disrupts cell membranes & interferes with DNA synthesis • Dissolves pulpal remnants & collagen – NO OTHER IRRIGANT OFFERS THIS HUGE ADVANTAGE

Answer 411

Occasionally allergies are reported • When used in high concentrations: • has greater cytotoxicity if extruded into the apical tissue • appears to have deleterious effects on dentine • Reducing flexural strength • Reducing the modulus of elasticity • Lots of1‐2% NaOCl gives benefits of disinfection without the disadvantages above. • Doesn’t remove dentinal debris/smear layer • need to use it with a chelating agent • If stored diluted before use degrades & ineffective

Answer 412

Use lots for as long as possible • Needs time to work • Need to continually refresh • Get it into the apical 1/3!! • measure and bend the needle so you know it’s to length • Increase the temperature of a low concentration solution • Improves the tissue dissolving capacity • Ultrasonically activate it • Acoustic streaming • And heating • REMEMBER never to wedge it in the canal, always make sure the tip is free by jiggling it as you irrigate

Answer 413

A broad‐spectrum antimicrobial agent • Effective against gram ‐ & gram + & yeasts • Bactericidal & bacteriostatic • Substantivity • Continues antimicrobial effect for up to 12 weeks • Few reports of allergy

Answer 414

Not been shown to be more effective than NaOCl • Does not dissolve pulpal tissue remnants • NaOCl & CHX if used together react forming an insoluble precipitate • May be useful as final irrigant due to substantivity but MUST completely dry the canal first • CHX also interacts with EDTA and forms a white salt precipitate

Answer 415

``` Excellent antibacterial properties • Acts as an oxidising agent • Kills a wide range of micro‐organisms • Bacteria – E.faecalis, fungi, TB, viruses, spores • Low cytotoxicity ```

Answer 416

stains dentine (must follow with NaOCl) • Works by vapour release • Unpredictable disinfection of the root canal system • Potent allergen

Answer 417

``` Dentine shavings • Cell debris • Pulp remnants • Smear layer reduces the ability of antimicrobial irrigants to enter dentinal tubules • May slow the antimicrobial effects of interappointment dressings also ```

Answer 418

It harbours microorganisms • prevents irrigants penetrating dentinal tubules • gives better microbial‐tight seal of RCS if removed • It can be removed with acids

Answer 419

Is a decalcifying calcium chelating agent • Removes dentinal debris formed on walls of RCS Removing the smear layer opens dentinal tubules and allows penetration of NaOCl • Use at 17% for 1 minute • Self limiting decalcifying action • Can penetrate 50µm into dentine • Strongest effect when used synergistically with NaOCl

Answer 420

Weak acid • As potent, maybe more so than EDTA • Cheaper • Effectively removes the mineralised portion of the smear layer

Answer 421

Use a 27 gauge (yellow) Luer Lock syringe with a side venting needle • Measure it so you know it is in the apical 1/3 of the canal! • Will need adequate coronal flare for this • Irrigation only goes ~1mm beyond needle tip • Use copious irrigation • Between EVERY instrument • MINIMUM 20mls/canal • You cant use too much, but can easily use too little

Answer 422

Sudden severe pain, • swelling, bruising •Treat by irrigating canal with saline until stops draining & dress, reassure, analgesics & review

Answer 423

Coronal portion of canal prepared BEFORE WL verified Irrigation introduced early • Removes bulk of microbes early • Better tactile sensation • Less changes in WL • Reduces torsional loads on files reducing risk of instrument fracture

Answer 424

Excessive flaring weakens the tooth as it removes dentine • Leaves tooth more susceptible to fracture • Could cause a strip perforation

Answer 425

``` Involves preparing the canal in 3 stages: • Creating a guide path • Prepare coronal 2/3 • Measure EWL from radiograph – subtract 3‐4mm. Set stoppers at this new length. • (find out the true/correct WL) • Prepare apical 1/3 ```

Answer 426

``` On R4 measure the digital radiograph by clicking on the ‘ruler’ symbol and then clicking on the radiographic apex and the incisal edge. Then subtract 3‐4mm from this length This gives the length to prepare the coronal 2/3 to. ```

Answer 427

``` Ensures canal is patent (not blocked) • Creates a path large enough for the NiTi file tips • Prevents tip binding & instrument fracture Watchwind/twiddle a precurved 10, 15, 20 K file in a wet canal +/‐ lubricant paste to the coronal 2/3 measurement ```

Answer 428

``` With stainless steel files you are ready to start with the niti ProTaper files • Set the silicone stops on the S1 & S2 files to the coronal 2/3 measurement (EWL minus 3mm) ```

Answer 429

The working length is the distance from a coronal reference point to the point at which the canal preparation & obturation should terminate. • The estimated working length is usually considered as the distance in mm’s from a coronal reference point (eg incisal edge) to the radiographic apex minus 1mm

Answer 430

``` Open the pre‐op periapical & select the ‘ruler’ symbol Click on the incisal reference point & around 1mm short of the radiographic apex. The PC will display the length of this in mm’s. This is the EWL If the canal appears curved, click on the curved point too to try and get a reasonably accurate EWL ```

Answer 431

- Radiographs • Electronic Apex Locator • Tactile sensation • Paper points

Answer 432

Use a size 15 ISO • Flexible K file • Use a sound, reproducible reference point • Usually the incisal edge or a cusp tip • Use paralleling technique with film holder • Ideally, the file tip should be 1‐2mm from the radiographic apex Ideally the file is not right at the radiographic apex as this is probably too long • Radiographs are not accurate for identifying the apical constriction....we “guesstimate” the apical constriction is around 1‐2mm away from the radiographic apex Despite their limitations radiographs are far more accurate than using paper points or tactile sensation • Ideally use electronic apex locator +/‐ radiographic WL

Answer 433

``` Buccal object rule: - When a radiograph is taken from a mesial angle the buccal object is displaced distally • lingual/palatal objects displaced mesially. • PAL, SLOB etc • Your PAL always moves with you (i.e object is palatal/lingual) • Same Lingual Opposite Buccal = SLOB ```

Answer 434

When the file makes contact with the periapical tissues an audible signal is triggered. • Due to a fall in impedance But must dry pulp chamber. • Often useful to add Glyde paste to end of file to get a contact and use with a precurved file. Will hear signal early if there is a perforation

Answer 435

Minimal risk of canal transportation, extrusion of irrigants or filling materials

Answer 436

``` Little removal of infected dentine Irrigation may not get to the apical third Interappointment dressings may not get into apical third May make obturation difficult ```

Answer 437

``` Removal of infected dentine & debris from the apical third Access for irrigants and interappointment dressings into the apical third ```

Answer 438

``` Risk of preparation errors & extrusion of irrigants and filling materials If obturating with heated techniques, likely to get an overfill ```

Answer 439

As a general rule, unless the apical 1/3 is prepared to a 30(F3),it will not be possible to get irrigation into the apical l/3 • Try to prepare all canals to a MINIMUM size of F3

Answer 440

Prepare to WL using Finishing File 1 • Place 20 Flexofile to gauge apical size • Prepare to WL using Finishing File 2 • Place 25 Flexofile to gauge apical size • Prepare to WL using a Finishing file 3 • Place a 30 Flexofile to gauge the apical size • If the 30 Flexofile is loose, repeat with Finishing Files F4 & F5 until correct apical size has been determined

Answer 441

If a canal is prep’d to F5 at working length: • Insert a 50 Flexofile to WL • Does it feel loose in canal? • If so, it is unlikely that gutta percha will satisfactorily seal the canal. • This needs treated as an ‘open apex’ • Mineral trioxide aggregate will need to be placed to form an ‘apical stop’ • Refer for completion of treatment with a specialist • Dress meantime in usual way

Answer 442

×1 syringe sodium hypochlorite ×1 syringe citric acid & leave in canal for 60 seconds ×1 syringe sodium hypochlorite Dry canal using absorbent paper points matched size

Answer 443

Make sure you have recorded the following in the patient’s notes: • The working length(s) (& what you have used to verify it) • The reference point(s) used for measurements • The size of the apical preparation i.e the final finishing file used • Eg. Canal prep’d to F4 at WL of 23mm (using EAL) from incisal edge mid‐ point

Answer 444

The tooth, injection site & gum (from RD clamp) may be tender for 2‐3 days might require analgesics • ibuprofen or paracetamol or both • A temporary dressing is in place and the patient should be mindful of this • May be numb for some mins/hours more, • take care not to traumatise soft tissues

Answer 445

Scotland 2004 endodontic instruments designated high‐risk & disposal after single use was deemed necessary • research showed endo files could not be cleaned effectively •a risk of residual contamination with nerve tissue and potential prions • BUT England is different.... • Following a review in 2010, now acceptable to re‐use same files on same patient • Stipulations for any re‐processing and traceability must be strictly adhered to. • & the rest of the world is different!!

Answer 446

To achieve a complete apical, lateral and coronal seal of the root canal system • To entomb the remaining bacteria in the permanently filled root canal space • Remaining organisms deprived of nutrition • Sealer kills organisms when in unset state

Answer 447

1. To prevent microleakage & exudate from entering into the canal (Transient Bactereamia) • 2. Prevention of coronal leakage • 3. To create a favourable environment for healing

Answer 448

Hermetic | Fluid tight or bacteria tight

Answer 449

Sealed against the escape or entry of air

Answer 450

A more appropriate term as root canals are evaluated for leakage of fluid

Answer 451

Biomechanical preparation • Thorough cleaning and correct shaping of root canal • Creation of the ideal ‘deep shape’ Creation of ideal shape between middle and apical thirds

Answer 452

No significant symptoms • No significant clinical signs • The tooth must not be Tender to Percussion, TTP • Canal must be clean and dry ‐ no blood, exudate or pus • Appointment time must be of sufficient length

Answer 453

The presence of : • A necrotic pulp • A draining sinus tract • A periradicular radiolucency on radiograph

Answer 454

``` Presence of acute signs or symptoms • Persistent exudate in root canal • Anatomical difficulties • Technical difficulties • Patient or dentist is tired or has lost patience ```

Answer 455

Allows medication with an antibacterial dressing • Calcium hydroxide paste will reduce the number of bacteria remaining following cleaning and shaping

Answer 456

``` No shrinkage • No solubility in tissue fluids • Good adhesion/adaption to dentine • No water absorption • No tooth discoloration Handling • Radiopaque require > 3mm aluminum • Setting in an adequate time • Easy to apply and remove using heat, solvents or mechanical instrumentation ```

Answer 457

Gutta‐percha • Silver points • Pastes • Resins

Answer 458

Gutta Percha 20% • Zinc Oxide Eugenol 60% • Metal Sulphates 15% • Waxes / Resins 5%

Answer 459

Has withstood the test of time • Introduced as an obturating material 160 yrs ago • Plastic – adapts well with compaction to canals • Easy to manage • Easy to remove • Low toxicity • Does not support bacterial growth

Answer 460

``` Allergic reactions to GP • Very rare Sealability: • Does not seal without the use of a sealer • Does not adhere to dentine • Warmed GP shrinks on cooling ```

Answer 461

Standardised, (cold compaction) | Non‐standardised, (warm compaction)

Answer 462

Sizes 15‐140, taper 0.02 | • Accessory cones for lateral compaction

Answer 463

Sizes correspond to taper of files, eg 0.04 –0.12 • Also pellets for injectable thermoplastic techniques GuttaFlow GuttaPercha Points GuttaPercha Obturator

Answer 464

* Size B accessory cones | * Use with Size B finger spreader

Answer 465

Poor success rate • Are not adaptable to canal, limited seal • Produce toxic products due to corrosion • Difficult to remove from canal • Silver cones should not be used as an obturating material

Answer 466

Zinc‐oxide and eugenol with the addition of toxic materials such as formaldehyde Plastics

Answer 467

Resin based | • Useful if patient has a diagnosed latex allergy

Answer 468

Do not use – paranesthesia if overfill reaches ID canal

Answer 469

Fast and easy to use – lentulo spiral filler

Answer 470

Difficult to avoid overfilling the canal • Formaldehyde containing pastes can cause paraesthesia • Sealing ability is unpredictable

Answer 471

A polycaprolactone core and sealer filling system • Components were developed to bond with each other and with canal wall to produce a bacteria tight seal with reinforcement of the root

Answer 472

Fast and fairly easy to use

Answer 473

Difficult to avoid overfilling the canal | • Sealing ability is predictable but technique sensitive

Answer 474

Gutta percha in itself, no matter how well adapted to the canal walls, will not create a seal • A sealer must be used to fill the spaces between the GP cones and between GP and canal wall to ensure a fluid tight seal • Aim for maximum GP and minimum sealer

Answer 475

``` Provide a fluid‐tight seal • No shrinkage with setting • Slow setting time • Fill canal irregularities, lateral and accessory canals • Bacteriostatic • Act as a lubricant • Adhere to dentine • Radiopacity ```

Answer 476

``` Zinc‐oxide eugenol • Calcium Hydroxide • Epoxy resin • Glass ionomer • Polyketone • Calcium silicate • Calcium trisilicate ```

Answer 477

RoekoSeal | Gutta Flow

Answer 478

Diaket | • Contains vinyl polymers mixed with zinc oxide and bismuth phosphat

Answer 479

Endo‐CPM‐Sealer • MTA Obtura • proRoot Endo Sealer • MTA fillapex

Answer 480

Bioroot | Biodentine

Answer 481

Cold lateral compaction 02 Taper point ProTaper points

Answer 482

``` Local anaesthetic, topical • Irrigants • RCT kit • Paper points • Finger spreader (Size B) • GP master apical cone, (MAC) and accessory points (Size B) • Sealer • Flame • Resin modified glass-ionomer (Vitrebond 3M ESPE, Fuji) ```

Answer 483

``` Place rubber dam • Swab tooth with chlorhexidine or NaOCl • Remove dressing and cotton wool • Irrigate with citric acid first to remove calcium hydroxide, then sodium hypochlorite Canals are filled with • Gutta-percha master apical cone (02 taper MAC or Protaper MAC) • Sealer • Accessory cones SIZE B FINGER SPREADER • Size B accessory cone ```

Answer 484

``` Recall 6-12 months • Ensure clinical and radiographic healing • No clinical signs • Evidence of bone healing in progress • Radiolucency decreasing in size • Continue follow up for 4 years ```

Answer 485

Select a Master Apical Cone, (MAC) the same apical size as Master Apical File, (MAF) • Measure cone to WL and place slowly into wet canal- to correct working length • Aim to achieve a frictional fit apically • There should be a definite stop when cone fits into place Master cones lack uniformity and can vary in tip size • Useful to take a cone-fit radiograph Dry canal with correct size of paper points measured to WL • Mix sealer and have spreader ready Coat MAC lightly in sealer • Insert into canal to correct WL • Use a slow pumping action to allow back-flow of sealer Remember that except for apical 2-3mm, the root canal will be much more tapered than the master gutta-percha cone • This space is fill by compaction of accessory cones that have been lightly coated in sealer Insert spreader with stopper: • 1-2mm short of WL with firm apical pressure (or as far as possible when using (Protaper MAC) • Leave in place 10-15secs with light lateral pressure Remove spreader with a slight rotation, and place accessory cone, lightly coated in sealer quickly into channel Repeat this process until no further accessory cones can be fitted • Take an obturation verification radiograph at this stage • Removal and reobturation is easier if over/underfill Cut off excess GP cones with a heated instrument (be careful not to touch patient’s lip) and compact the coronal GP firmly in a vertical direction using an endodontic plugger

Answer 486

Refining canal is required | • Using a smaller MAC

Answer 487

Lack of apical stop | • Use a larger cone

Answer 488

Remove ALL sealer and GP from access cavity to amelo-cemental junction to prevent discolouration of crown • Use cotton wool pledged soaked in alcohol (watch flame!!!) Seal entrance to root canal(s) and floor of pulp chamber with a resin modified glass ionomer cement

Answer 489

Light coloured composite resin in access cavity

Answer 490

Restoration depends on definitive restoration – crown / onlay • Seal access with amalgam or glass ionomer to prevent coronal leakage • Remove rubber dam • Check occlusion • Final radiograph

Answer 491

There is no need to wait for radiographic evidence of healing (6 mnth) before placing definitive restoration, providing RCT is a high standard

Answer 492

Gauge the size of the apical constriction using a 20K file, if this fits snugly, the prep can be complete at this stage However, generally the apical size needs to be at least 30 to allow irrigation into the apical 1/3 Take F2 to WL and gauge the foramen using a 25 K file If this fits snugly, the prep can be complete Or Take F4 to WL and gauge with 30K file, i fits snugly can be completed Use the same sized paper points for during the canal and same sized GP cone for obturating

Answer 493

Gauge the size of the apical constriction using a 20K file, if this fits snugly, the prep can be complete at this stage However, generally the apical size needs to be at least 30 to allow irrigation into the apical 1/3 Take F2 to WL and gauge the foramen using a 25 K file If this fits snugly, the prep can be complete Or Take F4 to WL and gauge with 30K file, i fits snugly can be completed Use the same sized paper points for during the canal and same sized GP cone for obturating