Restorative/DMS/ General Flashcards
Endodontic stainless steel mishapes
Ledges
blockage
perforations
transportation of apical foramen/Apical zipping
What are ledges?
ledges are internal transportation of the root canal that may be due to wrong working length or skipping file sizes
What is a blockage?
Apical blockage of the canal due to dentin chips, tissue debris of calcification of the canal
What are perforations?
communication between canal walls and periodontal space
How does transportation of apical foramen occurs?
it occurs as a result of the tendency of a the file to straighten up in a curved canal resulting in transportation of the apical foramen
Write the endodontic treatment up to obturation
- Acccess the coronal part of the tooth after taking pre-op PA and placing rubber dam and LA
- Remove any caries, locate canal orifices and create an isolated environment
- Prepare, irrigate and instrument root canals using protaper technique
- Obturate with GP,, assess restorability and seal
- provide final restoration
What are the consistuents of gutta percha?
20% GP
65% zinc oxide
10% radiopacifiers
5% plasticisers
What are the disadvantages of cold lateral compaction?
voids
incomplete fusion of GP cones
lack of surface adaptation
What are the disadvantages in using sized matched cones for endo obturation?
- it leaves very little space for accessory cones
What are the three thermal techniques used in obturation?
- warm vertical compaction
- continuous wave obturation
- carrier based obturation
What are the function of RCT sealers
Seal the space between dentinal wall and core
Fills voids and irregularities in canal
lubricates during obturation
What are the ideal properties of canal sealers?
good adhesion
easily mixed
slow set
no shrinkage on setting
non staining
What materials are used in sealers?
Zinc oxide eugenol based
GI
Resin sealers (epoxy)
Calcium silicate sealers
What are the advantages and disadvantages of zinc oxide?
- Advantages : antimicrobial and cytoprotection
- Disadvantages : soluble with time and irritant
What are the properties of glass ionomer as a sealer material?
- Dentine bonding properties
- minimal antimicrobial activity and greater solubility
What are the properties of calcium silicate sealers?
- does not shrink on setting
- non resorbable
- quick set (may require moisture)
- easy to use
What are the properties of resin sealers?
- good sealing ability
- good flow
- toxicity declines after 24h
- good penetration into tubules
- biocompatible
What to check in post op radiograph (RCT)
- length
- taper
- density
- GP removal at canal orifices and to facial CEJ
- any obturation errors
What to use to close canal orifices?
RMGI
flowable composite
Zinc oxide eugenol
What are the benefits of copper enriched amalgam?
- high early strength
- high corrosion resistance
- high durability of margins
- less creep
What is the function of zinc in amalgam?
- acts as an oxygen scavenger molecule and form slag
This prevents the oxidation of other metals in the amalgam alloy (such as tin and copper), which can otherwise weaken the final product.
How is copper enriched amalgam made?
By mixing silver copper eutectic particles with silver tin lathe cut particles to produce high copper y-2 free amalgam
Explain the process of delayed expansion in amalgam?
- alloys containing zinc when contaminated with moisture during condensation lead to expansion due to the release of hydrogen
This may cause internal pressure leading to pulp irritation
It can also cause high occlusal points leading to interference of occlusion and fracture
What is creep?
Creep is the slow
stressing and deformation of amalgam due to continuous low stress levels over a long period of time
What are the symptoms of amalgam creep?
- ditching of margins > microleakage > secondary caries
- Microleakage can cause pulpal irritation, secondary caries and discooration under the restoration
What areas in the upper and lower that give support in upper and lower complete dentures?
Upper = hard palate, maxillary tuberosity and residual ridge (secondary)
Lower = Retromolar pad, buccal shelf and residual ridge (secondary)
What provides support in partial dentures?
Rests (occlusal and cingulum)
What is kennedy classification?
anatomical classification that describes the number and distribution of edentulous areas present
What is kennedy class 1
bilateral free end saddle
What is Kennedy classification 2?
Unilateral free end saddle
What is kennedy classification 3
bounded saddle
What is kennedy class 4 ?
anterior bounded saddle crossing the midline
What does the palatal extension provide?
It provides increased mucosal support as a larger surface area is covered which can create a greater seal
Why do we place rest seats on anterior teeth?
it can provides indirect retention and bracing
why do we place rest seats on posterior teeth?
To offer support to the RPD preventing it from moving towards the mucosa , it can also aid in indirect retention and reciprocation
What is bracing in partial dentures?
Provides horizontal stabilization against lateral forces, ensuring the denture does not shift sideways during function.
How can bracing be achieved?
- minor connectors
- major connectors
- bracing arms
What are the different types of clasps for pre-molars?
- gingivally approaching I bar clasp
- modified t clasp
- circumferential clasp
What are the different types of clasps for molars?
Occlusally approaching single are clasp
Occlusally approaching circumferential clasp
Occlusally approaching ring clasp
Why is it beneficial to keep the gingival margin clear by not extending a partial denture framework to the anteriors?
- less mucosal coverage
- easier to clean gingival tissues
- less irritation
- better compliance
What impression materials are used for primary impressions in complete dentures?
- impression compound - non elastic
- alginate - elastic irreversible hydrocholloid
What are the consistuents of alginate?
- calcium sulphate
- Sodium alginate
- sodium phosphate
- trisodium phosphate
- flavouring
- filler particles
- salt and algenic acid
What are the consistuents of green stick?
- rosin
- carnauba wax
- talc
- stearic acid
Why place impression compound on a tooth?
- to record a single tooth crown preparation
What technique is used to record a single crown prep?
copper ring technique using impression compound
What is the procedure of the copper ring technique?
- select copper ring
- check it seats well around the tooth and it should extend to the gingival margin
- Fill the ring with impression compound and place around the tooth
What are the advantages of the copper ring technique?
- simple
- capture details accurately
How to manage GP that is exposed for more than 3 months?
- it requires re-root treatment as it is at risk of bacterial invasion
What are the restorative options for a fractured 26 MOD amalgam which has been root treated?
- Onlay or inlay depends on the size of restoration and cuspal coverage
- Crown (MCC)
- place another amalgam restoration
What is Nayyar core?
- amalgam acting as a core extending 3-4mm into the root by removing the GP
What are the features of the nayyar core?
- retention obtained by the undercuts in the divergent canals and pulp chamber
- 2-4mm GP removed from the canal and replaced with amalgam
- immediate placement of and coronal preparation can be done at the same appointment
What two restorative materials that can bond to amalgam?
RMGIC and GI
Which bond strength is stronger amalgam or composite?
composite
What special investigation should you do and why for a patient that attends with a space between 13 and 14 ?
Screen using BPE to obtain score and then decide on investigations according to score
- PGI - to assess plaque and bleeding levels
- 6PPC - to assess periodontal disease, pocketing, mobility and gingival recession
- Periapical radiographs to check for any periapical pathology and bone levels
- study models to monitor change over time
Other than aesthetics why would restoring this space be challenging?
- The space is small if the teeth are of good prognosis removing healthy tooth tissue for crowns or veneers would be a difficult choice to make
- If using composite to close the space by making 13 or 14 bigger this can be noticeable to the patient
What problems are associated with implant placement in the case of space between 13 and 14? (small space)
- inadequate space for implant placement (7mm required)
- inadeqaute bone levels due to periodontal disease
- cost
- periodontal disease
- Poor aesthetics as there is no good space for a tooth
What are the different types of pathological tooth wear?
- attrittion : physiological loss of teeth tissue due to tooth to tooth contact
- erosion : loss of tooth surface by chemical process by acid
- abrasion : physical loss of tooth tissue through an abnormal mechanical process that is indeoendent of the occlusion (toothbrushing)
- Abfraction : loss of hard tissue from eccentric occlusal forces leading to compressive and tensile stresses at the cervical fulcrum areas of the tooth
What are the BEWE scores ?
0 - no erosive wear
1 - loss of enamel texture
2- distinct defect hard tissue loss for less than 50%
3- hard tissue loss for more than 50% of the surface
how to calculate BEWE scores
Score each sextant then add it up to assess risk
2> none
3-8 low
9-13 medium
>14 high
Name three ways teeth can be desensitised?
- Sensitivity toothpaste
- Prime and bond to protect surfaces
- Fluoride varnish
What is the DAHL technique?
It is a technique used to gain interocclusal space in localised anterior toothwear cases without tooth reduction over a period of 3-6 months. An appliace such as a composite platform is placed anteriorly to increase the OVD by 2-3mm this allows the posterior teeth to erupt into occlusion and the anteriors intrudes. This then creates space for to allow restorations of the anterior teeth without further tooth reduction.
List 4 contraindicated groups for using DAHL technique?
- patients with active periodontal disease
- patients with TMJ problems
- patients who are on bisphosphonates
- post orthodontic treatment
- if dental implants exist
What are the consistuents of composite and give examples for each?
- Resin - Bis-GMA
- Glass - Silica or quartz
- Low weight dimethacrylate -TEGDMA
- light activator - camphorquinone
- Silane coupling agent - bifunctional molecule binding resin and filler
On a cervical abrasion cavity why would use RMGI instead of composite?
- due to poor moisture control at the cervical region, meaning that there is higher rate of composite restoration failure.
- RMIC has less polymerisation shrinkage and is best suites for cervical abrasion lesions where moisture cannot be controlled
What is an RPI?
it is a stress relieving clasp system which is used in free end saddle designs to prevent stress on the last abutement tooth and can also provide reciprocation
What are the components of the RPI system?
- Occlusal mesial rest
- Distal proximal plate (with 2-3mm undercut to guide movement)
- gingivally approaching I-bar clasp (at greatest prominence of the tooth)
What is the mechanism of action of RPI system?
The rest mesially acts as the axis or rotation. As the proximal plate and I bar rotates downwards and mesially around the axis of rotation during occlusal load. This allows it to disengage from the tooth and undercuts, thus avoiding potentially traumatic torque.
How would you identify a vertical bony defect?
PA radiographs
6 point pocket chart
Explain how vertical bony defects occur?
Commonly occurs in posterior teeth when plaque accumulate on one side of the tooth.The radius destruction of plaque determines this patterns. It is approximately 1.5-2mm and if the inter proximal bone is greater than this then the pattern is vertical/angular in nature.
How is vertical bony defects classified?
Using Goldman HM and Cohen (number of walls)
1 wall defect
2 wall defect - heals better
3 wall defect - heals better
What are the treatment options for vertical bony defects?
- Closed or open root surface debridement to allow healing by repair
- pocket elimination with osseous resection where the flap is repositioned apically
- Regenerative technique such as grafting for new bone, periodontal ligament and cementum
How do you determine the success rate of hygiene phase therapy?
- using SDCEP guidelines
- when bleeding is less than 10% , plaque less than 15% and pocket depths less than 4mm
- This may be no be achievable for all patients so a significant improvement in oral hygiene and reduction in pocket depths, bleeding and plaque from baseline readings can be deemed successful
If a patient is deemed suitable for periodontal regenerative surgery. What are the indications for this?
2 and 3 wall defects
Grade 2 furcation in mandibular teeth
Grade 2 buccal furcation in maxillary molars
If regenerative surgery fails for vertical bony defects , what are the alternative treatment options?
- Root resection
- XLA
- Palliative care
A fractured core and crown on a non root treated tooth , what features of the remaining tooth structure that will determine the prognosis of the tooth?
- Size of exposure
- Time of exposure
- Vitality of the tooth
- Remaining tooth tissue
What luting cement is used for MCC adhesive bridges?
RMGI luting cement (Relyx) - HEMA monomer
Dual-cure resin cement (panavia) - 10-MDP monomer
What makes RMGIC better than GIC? and why can it be used for enamel-dentine fractures instead of GI?
- prevents micro leakage more than GI
- Seals the cavity better
- Higher compressive strength
- Higher tensile strength
- Higher bond strength
- less solubility than GIC
Why GIC is not used as a conventional restorative material?
low mechanical properties:
* low toughness
* low fracture strength
* low wear resistance
Not good aesthetics
High solubility
lower bond strength
Why is RMGIC not good as a luting cement?
- contains HEMA which causes it to swell when contaminated with moisture
- Cytotoxic to the pulp
What are the ideal properties of a luting cement?
- thickness below 25 microns
- radiopaque
- Cariostatic
- low solubility
- high compressive strength
- biocompatible
- easy to use with good viscosity
What luting cement is used for fibre post?
dual cure composite luting cement
What are the components of temp bond?
- Base : zinc oxide, starch and mineral oil
- Accelerator - EBA, eugenol and carnauba wax
Can you bond zirconia?and why?
No because it cannot be etched.
*However it has micro-mechanical retention and self etching composite with relyx bonds well to sandblasted zirconia
Are lithium disilicate crowns strong? and how ?
Yes, they have good flexural strength as crack propagation through the material is difficult
What is a good use of lithium disilicate crowns?
- can be good in adhesive bridges as they create a strong bond with resin cements
- in anterior teeth
How do you bond to non precious metals?
By sandblasting them with aluminium oxide: using10 MDP (panavia) or 4META
What type of bridge is used to replace missing laterals?
Mesial cantilever resin bonded bridge (first choice)
Fixed-fixed bridge
What abutment teeth can be used for a resin adhesive bridge to replace a lateral incisor?
Canine or central incisors
Why are mesial cantilever designs preferred over distal cantilevers?
this is due to the increased biomechanical levering forces around the abutment, which acts as a fulcrum.
Mesial cantilevers distribute occlusal forces more favorably. Forces on the mesial side are typically directed more along the long axis of the supporting tooth, which can better withstand these forces.
Distal cantilevers tend to create a longer lever arm effect, increasing the potential for torque and rotational forces on the abutment tooth. This can lead to increased stress and potential failure of the restoration
What information is needed from a patient for technician to make a bridge ?
- bridge design
- master impression
- Bite registration
- Shade of teeth
What are alternative options for replacing lateral incisors other than bridges?
RPD
Implants
Do nothing
In a periodontal chart, what results would show teeth with poorest prognosis?
- Loss of attachment : pockets of more than 4mm means increased tooth loss
- Mobility : loss of bone support result in increased tooth loss
- Furcation involvement : more difficult to clean, more caries risk
What patient factors affect prognosis of teeth in periodontal patients?
- Poor oral hygiene
- Smoking
- Medical history such as diabetes and immunosuppression, pregnancy
- Drug history
What could be causing anterior drifting and increase in overjet in an elderly patient?
Active and uncontrolled periodontal disease
What are the Local causes of periodontal disease?
- Calculus build up
- malpositioned teeth
- overhanging restorations
- partial dentures
- poor oral hygiene
What are the systemic causes of periodontal disease?
- Medical conditions : such as diabetes, cardiovascular disease, immunosuppression, rheumatoid arthritis and osteoporosis
- Smoking
- Patient factors such as : stress, diet, obesity and pregnancy
- Medications such as : Calcium chanel blockers (amlodipine), anti-epileptics (phenytoin), immunosuppressants (cyclosporine)
What are the treatment options for an old patient presenting with periodontal disease?(mobility and drifting with increased overjet)
1) control periodontal disease : start with BPE and then hygiene phase therapy inculding OHI advice , patient education and control risk factors, review restoration margins and clear out any overhangs , denture hygiene , then review and move to step 2 if engaging
2) for mobility control splint the teeth
3) consider orthodontic treatment after that
What are the causes of denture stomatitis and loose dentures? (8)
- Immunosuppression : diabetes and HIV
- Poor dental hygiene
- Poor denture hygiene (wearing dentures overnight)
- Trauma from ill fitting dentures
- Xerostomia
- Systemic steroid use
- Broad spectrum antibiotic use
- high carbohydrate diet
What microbes are involved in denture stomatitis?
Candida species : candida albicans and candida tropicalis
Staphylococcus species - staphylococcus aureus and staphylococcus epidermis
What is the initial treatment plan for denture stomatitis?
1)local measures
* brush palate daily and after denture after eating
* clean denture by soaking in CHX twice daily for 15 mins
* Rinse mouth twice daily with CHX
* Do not wear dentures overnight
* Smoking Cessation
* Rinse after inhaler use
* Refer to GDP of suspected underlying medical condition
2)Denture adjustment
* Relign denture
* make new denture
* prescribe tissue conditioner
3) drug treatment if required
* systemic fluconazole - 50mg - 1x7days
* topical miconazole oromucosal gel 20mg/g - pea size on denture pea size on denture fitting surfaces 4x for 7 days after lesion heals
Give two topical agents that can be used for the treatment of denture stomatitis?
- Miconazole oromucosal gel 20mg/g
- Nyastatin oral suspension 100,000 units/ml
What would you see on the occlusal surfaces of a patient who have denture stomatitis and uses an inhaler?
- Erosion due to inhaler use
- patient should be advised to rinse after inhaler use
- fluoride varnish can be applied on the teeth to help protect them and reduce sensitivity
What to do to improve denture stomatitis in the short term until it is healed?
prescribe a tissue conditioner
Patient unable to tolerate new dentures after wearing the old one for 20 years , the previous ones has became loose over the past 18 months, what can be different between the old and the new denture? (5)
- OVD may have changed
- Path of insertion may have changed
- Different flange extension
- Different palatal extension
- different tooth shade and shape
What are the relief areas in a complete denture?
- incisive papilla
- mid-palatine torus
What method can be used to make a denture that a patient could tolerate when replacing an old denture?
Replica dentures
What methods can dentists use to improve the fit of loose dentures?
- Reline - soft or hard lining material
- Rebase
- Remake denture
Identify features on the hard palate that may cause problems with dentures?
- high arched palate
- tori on the palate
What things should be checked at the try in stage?
- Extensions
- Retention and stability
- Occlusal plane
- occlusion (RVD, OVD and freeway space)
- Appearance (Position of the teeth, shade and shape)
- Speech
What is the shortened dental arch?
It is a dentition where most posterior teeth are missing but there is still satisfactory oral function without the use of RPD
What is the minimum requirement for an SDA?
3-5 occlusal units remaining
* occluding pair of premolars = 1 unit
* occluding pair of molars = 2 units
SDA gives priority to maintain which teeth?
Anteriors and premolars
How many units for 2 occluding premolars and a pair of molars?
4 units
Why is periodontal disease is a contraindication for SDA?
- drifting of periodontally compromised teeth under occlusal load
- loss of alveolar bone leading to compromised denture bearing area in the long term
- loss of the neutral zone for denture teeth in the long term
- Distal tooth migration can occur in SDA due to increase in anterior load leading to interdental spacing that can be exacerbated by periodontal disease
What is the neutral zone in complete dentures?
It is the area in the potential denture space where the forces exerted outwards by the tongue are neutralised by the cheeks and lips action inwards
What skeletal classes are contraindicated with SDA and why?
In severe class II and III malocclusion as may cause occlusal instability leading to difficulties with function such as chewing , it may also lead to or worsen TMD symptoms
What metal is used for casting adhesive bridges?
- NiCr and CoCr sandblasted with aluminium oxide (50 microns)
What metal is used in adhesive bridges retainers?
CoCr or NiCr
What cement is used for adhesive bridgework?
Panavia (10MDP) - anaerobic dual cure resin cement
What is the 10 year and 5 year survival rate for RRB?
5 year - 80.8
10 year - 80.4
What are the indications for SDA?
- Missing posterior teeth but have 3-5 occlusal units remaining
- Sufficient occlusal contacts to provide sufficient occlusal table
- Patient does not want a complicated treated such as RPD
- Patient cannot afford dental treatment
- Good prognosis of remaining anterior and posterior teeth
What are the contraindications for SDA? (5)
- periodontal disease
- TMJ problems
- poor prognosis of remaining teeth
- Severe class II or class III
- any signs of pathological toothwear
Sub alveolar fracture of 12 and 11present with enamel dentine fracture >1mm exposure and >24h , what is the immediate management of tooth 11?
- Locate missing fragment of the tooth and refer to A&E if querying aspiration risk
- numb the area using LA and place rubber dam and carry out partial pulpotomy by accessing and removing part of the coronal pulp (2mm), and achieve haemostasis using cotton wool and pressure
- If haemostasis is achieved place CaOH in canal and seal with RMGIC and a composite restoration
- If haemostasis is not achieved or pulp is hyperaemic or not bleeding then carry out full pulpectomy and restore as above
A sub alveolar fracture is of poor prognosis why is that?
- It results in lack of coronal tissue to bond and support restoration. This leads to the inability to achieve moisture control for restoration and inability to take impressions for indirect restorations.
- Inability to establish marginal integrity and the patient will may have difficulty cleaning
Patient attends with caries on the palatal of 12; he is also sensitive to sweet under bridge, what type of bridges can you get anteriorly?
- fixed cantilever
- spring cantilever for incisors
- fixed fixed bridge
what pulpal diagnosis would you give to a tooth that is sensitive to sweet?and why?
reversible pulpitis
- discomfort from sweet stimuli and goes away within seconds when stimuli is removed
- Short sharp pain
- No TTP
- Pain on cold
- Well localised pain
What are the nerves affected in reversible pulpitis and what is this called?
a-delta and A-beta fibres due to hydrodynamic microleakage stimulation
What design would you use for replacing tooth 12 to decrease debonding?
An adhesive cantilever bridge from tooth 11. If this de-bonded it would fall out and would not become a plaque trap leading to less risk of caries . Also if an adhesive cantilever fails it is less destructive than other types of bridges.
What 4 faults can occur to cause a debond?
- Parafunctional habits
- Poor moisture control during cementation
- Unfavourable occlusion
- Trauma to face or oral cavity
- Poor oral hygiene
A patient undergone periodontal treatment presents as an emergency patient with pain on the 11 with swelling, TTP and lymphadenopathy - give 2 differential diagnosis?
- Periodontal abscess
- Periapical abscess
Give two special investigations to confirm diagnosis if suspected periodontal or periapical abscess?
- Sensibility testing EPT and ECT ( positive in periodontal abscess)
- Periodontal charting - check other teeth to see periodontal involvement
- PA radiographs to show if there is a periapical radiolucency present
State two ways that you can drain an abscess?
- incision or pocket retraction and irrigate with CHX/saline
Give initial management of a periodontal abscess
- incise and drainage of the abscess
- Gentle sub-gingival debridement short of the base of the pocket to avoid trauma and to limit spread of infection
- warm saline mouthwash or CHX
- OHI
- Analgesics for pain relief
- Antibiotics due to systemic involvement (amoxcillin 500mg 3x for 5 days )
- Review within 10 days and follow up with HPT
4 ways to check debonding of a bridge clinically?
- Probe around the bridge abutments and wing
- Push and check for any air bubbles
- Floss around bridge
- Check visually for. areas that have debonded
What is the best bridge option for a missing anterior tooth with adjacent teeth prepped?
- Spring cantilever as RRB cannot be used on adjacent teeth as they prepped
What factors should be checked by a dentist for placing implants?
General - smoking history, MH (bisphosphonate use)
Local - alveolar bone height and width and space available for implant (7mm between crowns)
What are the edentulous classifications for maxiilla?
Atwood cawood and howell classification
1- dentate
2- post extraction
3 - rounded ridge with adequate bone height and width
4- knife edge ridge with adequate height and inadequate width
5 - flat ridge , inadequate height and width (no alveolar process
6 - depressed ridge with basal bone loss
What classifications of ridges are considered poor?
4,5,6
Define retention in partial dentures?
The resistance to vertical displacement
Test resistance by pulling denture vertically from anterior teeth
What is indirect retention in partial dentures?
- resistance to rotational displacement of the denture
How does composite bonds to dentine ?
- acid etching dentine with 35% phosphoric acid removes the smear layer which expose dentinal tubules and collagen fibre’s
- Prime and bond applied and penetrated collagen fibres and dentinal tubules leading to a micro-mechanical bond
- prime and bond is a bivalent molecule which bonds to dentine through the hydrophilic end and bonds to composite through the hydrophobic end through molecular entanglement
acid etch removes smear layer , DBA creates hybrid layer between dentine
the bond between composite and acid etched enamel is micromechanical
How is porcelain treated to improve retention?
Etched with hydrofluoric acid producing a rough retentive surface , then it is treated by a silane coupling agent to produce a strong covalent bond
name 2 luting cements other than resin based that could be used to bond a crown?
- Gi luting cement (aquacem)
- Zinc phosphate cement
resin based bond better due to lower solubility and stronger bond
non resin cements are easier to handle and may provide fluoride release
What is the advantages of placing crowns in posterior teeth?
- Reinforce and strengthen tooth structure more than a direct restoration
Direct restorations may be more susceptible to fracture due to pressure configeration factors
How does a resin based luting cement bonds to porcelain?
- HF etched procelain
- silane coupling agent applied and produce a silane molecule that reacts with resin luting cement producing a strong covalent bond
C-C bond to composite and C-OH bond to porcelain
A silane coupling agent bonds organic meterials to inorganic materials
potential causes of symptoms on a patient presenting of pain to transient stimuli under a recently replaced MOD composite restoration
- Pulpal exposure
- uncured resins entering the pulp and causing irritation
- poor moisture control when placing the restoration
- insufficient coolant during preparation damages pulp
- Deep cavity with no liner placed
- high occlusal contacts
What 5 things you could do to avoid pain after replacing an MOD composite restoration?
- Using dental dam for good moisture control
- Placing lining material under restoration (RMGI)
- place and cure composite in increments
- Place pulp cap if pulpal exposure (Dycal)
- provide splint if patient have bruxism
- Apply fluoride varnish
Describe the 4 intraoral signs of ANUG
- halitosis
- crater like ulcers
- grey superficial layer that can be wiped off
- reverse gingival architecture
- painful ulceration on the tips of the interdental papilla
- bleeding
What bacteria is involved in ANUG?
fusobacterium species
provotella intermedia
What 4 risk factors predispose someone to anug?
- Smoking
- Stress
- immunosuppression
- Poor oral hygiene
What is the initial management of ANUG?
- Check airway if compromised or not , if compromised call 999
- Prescribe analgesia
- Start step 1 periodontal therapy as symptoms allow ( LA may be required)
- prescribe CHX mouthwash or hydrogen peroxide
- If systemic involvement prescribe : metronidazole -> doxycycline -> azithromycin
- Review within 10 days , carry out further PMPR
What is TIPPS for oral hygiene?
- Talk - about causes, risks and prevention of periodontal disease
- Instruct - the best way to perform effective plaque removal
- Practice - practice cleaning teeth and performing interdental brushing in clinic
- Plan - plan how OH can fit in the patient daily routine
- Support - follow up with patient
Why might a post and core debond? (5)
- post or core fracture
- bruxism
- inadeqaute moisture control when cementing
- root fracture
- Caries
Reasons why fracture occurs at the junction of the post and core?
- Parafunctional habits (bruxism)
- Inadeqaute ferrule
- Caries
- poor post placement
What are 3 ways of removing a post?
- mosquito forceps
- masseran kit
- eggler
- ultrasonic vibration
A 28 fit and healthy patient showing periapicals of generalised bone loss , what is your diagnosis?
generalised agressive periodontitis
What 4 signs can lead you to the diagnosis of aggressive periodontitis?
- Generalised loss of attachment affecting at least 3 other teeth except 6s and incisors
- Affect patient under 30 yrs
- vertical bony defects
- Episodic nature of destruction of periodontal attachement and associated structures
- Rapid progression of bone loss
- plaque levels not consistent with disease level seen
What are the clinical and lab investigations for aggressive periodontitis?
- Thorough history taking
- BPE, MBPS, 6PPC
- cervicular fluid swab for microbiological analysis
How to decide prognosis of individual teeth in periodontitis?
- Loss of attachment
- Mobility
- Furcation involvement
What is the treatment plan for aggressive periodontitis?
- Perform Step 1 according to BSP guidelines
- Refer to specialist
- prescribe CHX
What is the justification behind using a lingual bar connector ?
- Give clearance for the patient to clean
- 8mm clearance from gingival margin to FoM (3mm from gingival margin, 4mm bar , 1mm above floor of mouth)
- well tolerated (pt comfort)
What features on an RPD might provide indirect retention?
- RPI systems
- Rest seats
- Major connector
- guiding planes
Why would mechanical root surface debridement not be successful in eliminating pocket bacteria? (5)
- Inadequate RSD due to poor operator technique and experience
- Specific pocket sites are not accessible
- Failure to disrupt the biofilm
- Patient not compliant with OH
- Patient is immunocompromised
ABs may not reach the pocket depth
Do not use antibiotics when there is no systemic involvement
When to use antibiotics?
- when there is systemic involvement or pt is immunocompromised
How to manage a periodontal abscess that have systemic involvement?
- Sub-gingival scaling short of the root base (avoid infection spread and damage)
- Drain pus by incision or through pocket
- Give patient advice on analgesics for pain relief
- Use 0.2% CHX until acute symtpoms subside
- ABS : amoxicillin or metronidazole
Amoxicillin 500mg , metronidazole 200mg three times daily for 5 days
What is a periodontal abscess?
acute exacerbation of a periodontal pocket caused by trauma to the pocket epithelium or obstruction of the pocket entrance due to bacteria and food accumulation without adequate cleaning leading to periodontal abscess
What 3 criteria must be fulfilled before obturation?
- Tooth must be asymptomatic
- Canal should be fully dried
- Full biomechanical cleaning on all canals
Name the consistuents of GP
GP
zinc oxide 65%
radio-pacifiers 10%
plasticisers 5%
ZnO can alleviate pain and is bacteriostatic + a good seal
What is the function of canal sealers when used with GP cones? (3)
- seal space between dentinal walls and core
- fill voids and irregularities in canal and between GP cones
- Lubrication during obturation
What types of sealers are used for obturation? (5)
- CaOH (Dycal)
- Epoxy resin filler (AH26 plus)
- Bioceramic sealer (calcium silicate and calcium phosphate)
- RMGI
- ZOE
How do you assess obturation on a radiograph? (4)
- check correct length
- check correct taper
- check density and that GP is well compacted with no voids
- check that GP and sealer is removed at facial ECM in anterior and Canal orifices in posteriors
Why do we need to obturate? (3)
- seal remaining bacteria
- prevent reinfection
- provide apical and coronal seal
Give 4 methods of obturation? (CCCW)
- cold lateral compaction
- warm vertical compaction
- continuous wave compaction
- carrier based obturation (thermafil)
What 2 temporary restorations can be provided for a patient with a fractured crown core on tooth 11 during endo?
- RMGIC
- provisional post crown
- Vacuum stent with tooth (if tooth is present)
Post materials
Metals - SS, type IV gold
Ceramics - aluminia and zirconia
Fibre - Carbon and glass fibre
Core materials
- composite
- amalgam
- glass ionomer
What factors can determine post length?
- root length and morphology
- type of post used
- crown length
- remaining tooth structure
What are the ideal dimensions for post placement?
- leave 4-5mm of GP in canal
- At least half of post length should go in the root
- 1:1 post length to crown height
- width should be no more then 1/3 of the root width at norrowest point
What materials can be used to cement post and core?
- GI luting cement
- composite resin luting cement
Explain the main features in mastication and ingesion?
- ingestion > movement of food into mouth
- stage 1 oral transport > movement of food from front to back of mouth
- mechanical processing > food mixes with saliva and produces bolus which is sqaushed against hard palate by the tongue , and food chewed by molars and premolars
- stage 2 oral transport > bolus moves from anterior to posterior of the oral cavity , solid food moves to pharyngeal surface of the tongue then to oropharynx and liquids held by posterior oral seal then into oropharynx
- swallowing : bolus moves from pharynx to esophagus
What muscles are involved in ingestion?
buccinator and orbicularis oris
What anatomical structures are involved in stage 1 oral transport?
- tongue
- retraction of hyoid bone
- narrowing of the oropharynx
What muscles are involved in swallowing?
- upper esophageal sphincter
- epiglottis (preventing backflow)
- peristalis moves food to stomach
What factors improve masticatory performance?
- Sufficient oral saliva
- Sufficient dentition
3 aspects of oral function regarded by proponents of the shortened dental arch as acceptable?
- sufficient occlusal and mandibular stability
- Occlusal attrition
- Satisfactory oral function
What is occlusal stability?
Stability of tooth position in relation to its spatial relationship in the occluding dental arches
What is occlusal stability ?
It is the stability of tooth position relative to its spatial relationship in the occluding arches
What happens to an upper arch with complete dentures and lower anterior teeth present if the lower is not provided with a partial denture?
- Combination syndrome leading to a flabby ridge
This is caused by forces directed at the anterior region of the complete denture resulting in excessive and rapid bone loss in the anterior maxillary ridge that is replaced by excess fibrous tissue
- 68 year old patient with upper and lower partial acrylic which are poorly fitting
- upper arch have deep to moderate caries
- Periodontal pockets 3-4mm with not radiolucencies
- Radiopacities in relation to all the roots
- minimal periodontal bone loss
- on medication for Paget’s disease
What might cause the radiopacities on the radiograph?
Paget’s disease causing hypercementosis
other dental changes of paget’s disease include : loss of lamina dura and tooth migration due to bone enlargement
What is the mechanism of action of local anaesthesias in pain control? (3)
- bind to sodium channels in nerves blocking it and preventing the influx of sodium
- this blocks the action potential generation and propagation
- block presists according to the number of Na channels blocked
What are the consistuents of LA?
- Aromatic region - hydrophobic
- Ester/amide bond - anaesthetics part
- Basic amine side chain - hydrophilic
Access cavities for endodontic treatment
Describe the appearance of attrittion? (4)
- lesions on occlual and incisal surfaces
- flattening of incisal edges
- reduction of cusp height and flattening of inclined teeth planes
- Wear on restorations
Describe the appearance of abrasion (4)
- labial/buccal and cervical lesions on premolars and canines
- V shaped or rounded lesions
- notching of incisal edge
- Sharp margin at enamel edge where dentine is worn preferentially
Describe the appearance of abfraction
- wear at cervical margin shows as V shaped due to eccentric occlusal forces leading to compressive and tensile stress on the cervical margins
Draw and label posselt’s envelope
E - edge to edge
RCP - retruded contact position
ICP - intercuspal contact position
Pr - protrusion of mandible
R - max mandibular opening position when with no condylar translation (rotating condyles)
T - Max mandibular opening with full condylar translation
What is the average biological width?
2mm (connective tissue 1mm ; junctional epithelium 1mm)
the combined height of the connective tissue attachment and the epithelial attachment above the alveolar bone
Why is length of walls important in crown preparation?
prevents tipping displacement (longer walls are better)
What are the types of finish line configurations in crown prep (5)
- knife edge
- bevel
- chamfer
- shoulder
- beveled shoulder
In how many planes should you prepare buccal aspect in crown prep?
2 planes (apical and coronal)
palatal/lingual is completed in one plane - follow palatal contour for anteriors and canines
Reduction dimesions for crowns
Describe the setting reaction of GI
- acid base reaction: glass + acid -> salt and silica gel
- Consist of 3 phases :
Dissolution - acid dissolves glass particles releasing ions
Gelation - formation of calcium polyacrylate matrix leading to initial set and early strength
Hardening - aluminium cross-linking leading to increased strength, final set and fluoride release
Denture anatomy
What is the new periodontal classification (2018)
How is gingival recession graded ?
Using miller classification
Examples of developmental bone pathologies?
- Tori - benign bone growth in mouth (mandibular tori)
- Fibrous dysplasia - fibrous tissue replace bone
What are the characteristics of ghost images on a radiograph?
- Higher due to vertical beam angulation (-8)
- Horizontally magnified and distorted
- opposite side
- further forward - due to change in anterior posterior position
What is compton scatter effect?
- X-ray photon interacts with outer shell electrons which is greater than the electron energy
- The electron is then ejected taking some of the photon energy which causes the photon to change direction and loose some energy
- Results in a decreased image quality
What is photoelectric absorption effect in radiology?
- The photon interacts with inner shell electron which has a higher energy than the photon
- This results in the x-ray photon disappearing
- the energy difference is emitted as light as the electron is ejected as a photoelectron
- image appears white or grey depends on photon involvement
What is paralleling technique in radiology?
- image receptor and object are parallel but not in contact
- beam is perpendicular/divergent
- image receptor and object are some distance apart but with short spacer cone
- short spacer cone allows short fsd
- requires film holder and stabilisation with cotton roll
What is bisecting angle technique in radiology?
- image receptor and object are not parallel and partially in contact
- beam is perpendicular
- image receptors are close together at crown but apart at apex
- can be done without film holders
- use fsd 20cm
Label Condyle, hard palate, zygomatic buttress, styloid process, soft palate
hyoid bone, nasal septum, ear lobe, bite peg and ghost image
Label denture bearing areas anatomy of the upper and lower arch
