SUPERDOC Flashcards
3 ways tumours can spread
Haematogenous- through blood/ circulatory system
Lympathic
Transcoelomic- through body wall into chest cavity/ abdomen
How can cancer be classified?
BY TISSUE TYPE
- carcinoma, sarcoma, myeloma, leukemia, lymphoma, mixed
BY GRADE
- abnormality of cells compared to surrounding normal tissue
- Low grade- well differentiated cells that closely resemble normal specialised cells. High grade- undifferentiated cells that are highly abnormal.
Grade 1-4
BY STAGE
TNM staging - tumour size, degree of regional spread/node involvement, distant metastasis.
What are some signs of cellular atypia?
hyperchromatism,
pleomorphism,
changes in size/number,
mitotic bodies in epithelium not just basal cell layer
Risk factors for oral cancer
smoking large v alcohol poor oh poor diet chewing betel quid/ tobacco EBV, HSV, HPV
What is stomatitis?
Infection of mouth and lips
What is primary gingivoostomatitis?
combination of gingivitis and stomatitis, mouth and gum swelling. lesions in mouth resembling canker sores. Normally initial presentation of herpes simplex virus.
Lies dormant in the trigeminal ganglion, reactivated onto lip/vermillion border with stress, ill-health such as a
cold
Symptoms Primary gingivostomatitis
pain bleeding gingiva ulceration unable to eat malaise pyrexia lymphadenopathy
How to test for primary gingivostomatitis?
viral culture
PCR
antigen tests
Tx gingivostomatitis?
Hydration
Bed rest
If early- aciclovir
Triggers of herpes?
UV light, feeling unwell, stress, trauma and immunosuppression
2 Oral mucosal diseases caused by coxsackie virus
Herpangina + Hand foot and mouth
2 Disorders of esptein-barr virus:
Hairy Leukoplakia, Glandular Fever/Mononucleosis, OSCC
What are these all & Place these in order of incidence (Asinic cell carinoma, adeniod systic cell carcinoma, mucal epidermoid
carcinoma, pleumorphic adenoma, warthin tumour)
SALIVARY GLAND TUMOURS
Pleomorphic Salivary Adenoma, Warthin Tumour, Adenocystic Carcinoma, mucal epidermoid carcinoma, asinic
cell carcinoma.
3 Histological findings of pleomorphic adenoma
Mixed Tumour: Duct epithelium, myoepithelial cells, myxoid
and chondroid areas.
Histological features of Warthin‛s Tumour:
cystic with spaces, brightly stained epithelium and potentially
including lymph tissue.
Tx options and surgical procedure for removing salivary duct calculus
Tx options: Surgery, Ultrasound, radiologically guided stone removal: basket/balloon, sialoendoscopy,
lithotripsy and laser ablation.
Identify stone, LA, holding suture, incise at duct orifice and along duct, squeeze out or ultrasonic/bur to
separate stone/calculi, suction
6 types of candidosis
Acute pseudomembranous (thrush), Acute erythmatous (Antibiotic sore mouth), Chronic erythmatous (denture induced), Chronic hyperplastic (Commisures of mouth, increased malignant potential), Median Rhomboid Glossitis (chronic), Angular Cheilitis
Aetiology candidosis
Smoking, local immunosuppresion, systemic immunosuppresion, diabetes, denture issue, underlying disease/deficiency, xerostomia, HIV .
Investigations candidosis
FBC, Haematinics, Blood glucose, dry mouth, HIV, Swab/Rinse.
Disadvantage of rinse testing
Only indicates presence of microbe not role in infection
Advantage of smear testing
Includes local cells and tissues .:. can show implication of microbe in infection.
:( can be uncomfortable for pt
tx candidosis
Fix deficiency, treat underlying disease, fix diabetes, stop smoking, inhaler use instruction, OHI and denture hygiene instruction, fix denture problem, diet advice to reduce refined carbs.
4 antifungals commonly used
CHX, nystatin, fluconazole, miconazole
For CHX:
Type, method of action, prescription and any warnings
T: bis-biguanide
MoA: dicatatonic- one binds to pellicle, other to cell membrane to increase permeability .:. at high conc leads to cell death
P: 0.2% in 10ml, 2 x daily
W: anaphylaxis, 0.18% is bacteriocidal
For Nystatin:
Type, method of action, prescription and any warnings
T:Polyene MoA: Bind to sterols in fungal membranes, allowing leaking of metabolites P:Oral suspension 100,000 units/ml Send: 30ml Label: 1ml after food 4 x daily for 7 days up to 28 days W: need to hold suspension near lesion for 5 mins
For Fluconazole:
Type, method of action, prescription and any warnings
T: Tri-azole MoA: Interfere with primary sterols in fungal membranes. Egosterol Inhibition P:50mg capsules Send: 7/14 capsules Label: 1 capsule daily Up to 28 days. W: Not for users of warfarin or statins due to liver inhibition
For Miconazole:
Type, method of action, prescription and any warnings
T: Imidazole MoA: Interfere with primary sterols in fungal membranes. Egosterol Inhibition P: Gel: Send:80g tube. Label: Pea-sized amount, 4 x daily after food, until 2 days after lesions appear W:Not for users of warfarin or statins due to liver inhibition
causes xerostomia
Drugs, Dehydration, diabetes, Sjogrens syndrome (Primary or secondary), mouth breather, trauma to gland, gland/duct blockage/ Salivary gland issue/pathology, smoking, age, radio/cancer therapy, AIDs, sleep apnoea. somatoform disorder,
Sjogrens syndrome?
Autoimmune condition affecting parts of bodies producing fluids like tears
- dry eyes, mouth ,skin, vagina
Investigation for SS?
6 diagnostic criteria : Eye symptoms, mouth symptoms, occular signs (schirmer test <5mm in 5 mins), abnormal unstimulated salivary flow(<1.5mls per 15 mins), autoantibodies (Ro/La), \+ve labial gland Bx
FBC, try to stimulate saliva/palpate ducts and gland to extrude saliva, radiograph for stones, MRI and US.
tx xerostomia?
: Treat underlying cause: Correct dehydration, modify drug regime, control diabetes, treat somatoform
disorder
Preventative Oral Care: Diet, Fluoride, Tx Planning, CHX can be useful to prevent infection.
Symptomatic Relief: Saliva substitutes (Biotene gel), Salivary stimulanats (pilocarpine). Don ‘t use acidic !
Indications for antibiotic therapy?
Adjunct to surgical therapy, if inaccessible to surgery initially, if
systemic involvement: SIRS: HR>100, RR>20, WCC<4/>12, Temp<36/>38.
What is recurrent apthous stomatitis?
Types?
where round/ovoid ulcers appear repeatedly on oral mucosa
minor, major, herpetiform, Behcet’s
Describe minor RAS
Minor: <10mm Round/oval. Red halo, yellowish base. 1-20 per crop Chiefly non keratinizing mucosa Heal in 1-2 weeks, without scarring
Describe major RAS
Major: >10mm Oval or irregular. Red halo, yellowish base. <5 per crop Keratinizing/non-kerat inising: especially soft palate! Heal in 6-12 weeks and sometimes with scarring.
Describe Herpetiform RAS
Herpetiform: < 5 mm Round or oval, often coincide into larger ulcers. 1-200 per crop Non-keratinising mucosa
Describe Behcet’s RAS
Heal in 1-2 weeks without scarring Behcet's Numerous oral ulcers Part of multisystem ulceration problem/pathology. Auto-immune
Causes of Recurrent Apthous stomatitis
Host: genetic, (behcets) nutritional deficiencies, systemic, endocrine imbalance, immunity issue.
Environmental: internal, external (keobner effect where trauma induces lesions)
Allergy: SLS
Tx RAS
Correct deficiency, correct systemic disease, remove allergens, remove trauma
Topical immune modulation: steroid use. betamethasone MW (0.2% 2-3 xdaily) or beclomethasone inhaler (50ug puffs 2-3x daily)
Systemic: prednisolone, aziathioprine
Dental problems arising from recurrent Apthous stomatitis pts
Dehydration
Difficulty eating .:. Malnutrition
Interfere with instruments
Characteristics of a zygomatic orbital complex fracture?
Assymetry Pain Bleeding Swelling Abnormal occlusion Diplopia Limited mouth opening Decreased acuity Numbness
Radiographic views needed for ZOC fracture diagnosis
10 OM
30 OM
Frontal
Use Campbell’s lines to read radiographs
Tx for ZOC #
Atls; Advanced trauma life support : abcde
Indication for tx : symptomatic (eyed nerve problems, displacement) assymptomatic: defection radiograph, suspicion of late enopthalmus.
- Conservative management
- Open reduction with internal fixation
- Closed reduction.
If retrobulbar haemorrhage (bleeding behind eye) w. Intense pain and reciting in visual acuity. treat with lateral canthotomy.
OAC:
Risks, causes, investigations, management
Risks/causes: iatrogenic when root of upper posterior is in close proximity to sinus floor. Inappropriate technique. Too much force.
Investigations:
Pre-assessment of size and position of tooth.
During xla; suction, good light, direct vision, bubbling of blood, nose holding test. None at furcation area. Probe?
Management: auto: inform pt, give instructions- meds, refrain from blowing nose, steam inhalation, avoid straws, no smoking.
If small: encourage clot, suture margins, horizontal mattress.
If large: buccal advancement flap, 5-10 days antibiotics. Refer if in doubt.
OAF:
Risks, causes, investigations, management
Risks/ causes: following oac
Investigations: pt history Of: problems with speech, singing, fluid consumption, wind instruments, smoking, using straw, bad tastes odour, pain, sinusitis type symptoms
Management: excise sinus tract/fistula, buccal advancement flap, buccal fat lad with advancement, palatal flap, bone graft, antibiotics 5-19 days refer.
Fractured tuberosity:
Risks, causes, investigations, management
Risks/causes: last standing molar w. No teeth mesial. Unknown unerupted molar, unknown pathology, inadequate alveolar support.
Investigations: noise. Movement visually, palpation, multiple teeth moving, tear on palate.
Management: small: remov portion of bone and explain to pt. then suture.
If large: reduce, fix with splint, extirpate pulp, place sedative , ensure occlusion free. Pt instructions to keep bone stable (chewing pop side, no smoking), antibiotics, antiseptics, post op instructions. Wait for 8 weeks then surgically remove.
Root/ tooth in Antrum :
Risks, causes, investigations, management
Risks/causes: Iatrogenic,
Inappropriate force and technique.
Investigations: radiographs: opt, occlusal, periapical, pt symptoms of sinusitis,
Management: retrieve if visible and accessible. Refer if not. Approach through socket like oaf .endoscopic retrieval, Caldwell luc. (Buccal sulcus window in bone). Wash out/ ribbon
Crown/root fracture: Risks, causes, investigations, management
Risks/causes: gross caries, thick cortical bone, Root shape/number, hyoercementosis, ankylosis, inappropriate technique, force, instrument
Investigations: observation of extracted fragments.
Management: reassure pt, readdress technique and approach (root froceps or cryers required)
Surgical : design and retract flap.
Straight electrical Handpiece with copious water coolant
Marrow and deep buccal gutter to find application
Point.
Good vision, access and suction.
Muscles to check for TMD
Masseter, temporalis, lateral pterygoid
Signs and symptoms of TMD
Symptoms: Pain, click, limited mouth opening, tender muscles, otalgia (ear pain), lock jaw.
Signs: hypertrophic muslces, tender muscles, clicking or crepitus, tender joint, limited mouth opening, wear facets, tongue scalloping, Linda alba.
Management of TMD
Conservative advice: reassurance, counselling regarding: soft diet, mastication bilaterally, no wide opening, no chewing gum, don’t incise food, reducing or stopping parafunctional habits (nail biting, grinding, clenching), advice regarding stress, supported yawning.
Splints: bite raising appliance, anterior repositioning splint
- aids in breaking habits, stabilising muscles, psychological reconditioning
physiotherapy, heat, acupuncture, relaxation, hypnotherapy
Signs and symptoms of mandibular fracture
pain swelling bruising occlusal derangement numbness of lower lip loose teeth bleeding aob facial assymetry mandibular deviation trismus muscle spasm sublingual haematoma
Radiographs needed for mandibular fracture
opt, pa mandible or CBCT
tx for mandibular fracture
control pain and infection
if undisplaced: conservative management
if displaced: fixation, closed fix with IMF/ ORIF
Factors causing mandibular displacement
Direction of fracture line, opposing occlusion, magnitude of force, mechanism of injury, intact soft tissue, other associated features, number of traumatic hits
Published guidelines for removal of impacted wisdom teeth?
SIGN and NICE
Incidence of a) temporary loss of sensation
B) permanent loss
A) 10-20% . Raised if close proximity to Id canal or difficult extraction
B) permanent: 1% (raised as before)
Post operative complications of removal of impacted wisdom teeth
Pain swelling bruising Trismus Sensory changes Altered taste Localised osteitis Infection Bleeding Haematoma
Peri operative complications of impacted wisdom teeth removal
Unplanned fracture of tooth or root Fracture of adjacent tooth/ restoration Fracture of alveolus Excessive bleeding Damage to soft tissues Burns
U: fracture tuberosity, oac, loss of tooth into antrum or pterygoid space.
L: lingual plate fracture, loss of tooth to lingual space, direct trauma to IAN bundle
6 pieces of info on radiograph showing interruption of ID canal by lower 8s
Diversion of ID canal
Darkening of root where crossing ID canal
Interruption of laminar dura (white lines)
Deflection of root
Narrowing of ID canal
Just a apical area (dark unusal looking area under apices
Describe the surgical extraction of impacted teeth
LA: LA +/- IV sedation or GA
ACCESS: buccal mucoperiosteal flap +/- lingual flap.
ST RETRACTION: gives surgical access, protects ST, Howarth’s periosteal elevator or rake
BONE REMOVAL: electrical straight handpiece, saline coolant, round/fissure ss or tungsten carbide burs, narrow but deep buccal gutter to allow access for sound application point.
TOOTH DIVISION: horizontal/vertical section.
ELEVATION: direct vision, force away from major structures, actions: wheel and axel, wedge, lever.
FORCEPS: figure of 8 or buccal pressure
DEBRIDEMENT: physical with a file or hand[riece. Mitchell’s trimmer for ST. irrigation with saline. all granulation tissue removed
SUTURE
HAEMOSTASIS: pressure with damp gauze
POST OP INSTRUCTIONS
POST OP MEDS
Flap design points
Wide base, relief, full thickness, one firm continuous stroke, no sharp angles, no crushing, tissue moist, margins over bone, aim for healing by primary intention
Purpose of suturing
to reposition tissue, compress BV, cover bone prevent wound brekadown, achieve haemostasis. promote primary intention healing
Post op instructions
No rinsing for several hours, soft diet, caution post LA no smoking/alcohol hot salty mouthwashes, dont disturb if bleeding- damp gauze, thenA&E if persists pain swelling bruising, jaw stiffness avoid eating on that side keep area clean
Post op meds
analgesia: before LA wears off- paracetamol 1g 4 x daily max
ibruprofen 400mg 3 x daily
CHX
Use of iodine in wisdom teeth extraction
used to be used for prophylaxis
3 types of damage that could be caused to nerves while removing a tooth
NEUROPRAXIA: bruising
ANOTMESIS: sheath slice
NEUROMESIS: severed nerve
Risk of removing wisdom teeth
Pain, swelling, bruising, jaw stiffness, numbness or tingling (IDN/ lingual + temp/permanent)
bleeding, infection, dry socket, dyasthesia + altered taste
Signs/ symptoms Periocoronitis
Pain from third molar region, swelling, inflamed periodontium, food packing, bad breath, pus discharge, trauma to operculum, dysphagia, pyrexia, malaise, regional lymphadenopathy
Tx Periocoronitis
+ management
Incision of acute periodontal abcess + /- LA
CHX irrigation 10-20ml (blunt needle under operculum)
XLA of upper 3rd molar if traumatising,
Management:
Hot salty MW/ CHX MW instructed for pt
Analgesia
advice: keep fluids up, soft diet,if systemically involved: antibiotics
Assymptomatic: monitor
symptomaic/ pathology: XLA/ surgical removal 3rd molar(s), coronectomy if close to ID canal
When is removal of 3rd molars not advised?
if look to erupt successfully and have functional role
MH renders unacceptable risk
Deep impaction with no history of pathology
Risk of surgical complication/ fractures too high
If assymptomatic and contralateral tooth is being extracted under LA
Indications for 3rd molar removal
Previous/ present Significant infection associated
Predisposing factors precludes ready dental access
MH where risk of renention outweighs risk of removal (pre-radiotherapy)
Tooth transplant
If under GA for removal of other 8
Periocoronitis/cellulitis/abcess/untreatable pulpal pathology
caries
cyst
if causing external resorption
perio
tumour removal
function of bisphosphonates
decrease bone turnover by inhibiting formation, recruitment and activity of osteoclasts.
used for osteoporosis, bone metastases or malignancy.
especially active in areas of high bone turnover e.g jaw. decreased blood supply and bone turnover may lead to necrosis.
What is BRONJ?
Bisphosphonate related osteo-necrosis of the jaw ,
exposed necrotic bone in maxilla or mandible that has persisted for more than 8 weeks in pts taking bisphosphonates, w no history of radiation therapy to jaw.
symptoms MRONJ
delayed healing following dental extraction or other surgery pain ST infection swelling numbness parathesia exposed bone
what increases risk of BRONJ
previous diagnosis of BRONJ
Taking bisphosophonate as part of management of malignant condition
other non-malignant systemnic condition affecting bone (paget’s disease)
under care for rare medical condit (osteogensis imperfecta)
concurrent use of systemic corticosteroids or other immunosuppressants
coagulopathy, chemotherapy, radiotherapy
sirs?
systemic inflammatory response syndorme
HR > 100
RR>20
Temp <36 or > 38
WCC < 4 or >12
Fasical spaces
submandibular, buccal, , infraorbital, submental, retropharyngeal
name for bilateral infection of submandibular space
ludwigs angina
type of severe cellulitis involving floor of mouth
submandibular space made up of two compartments: sublingual and submylohyoid
dry socket name
what is it
alveolar osteitis
= painful condition where blood clot fails to form or dislodges before wound heals
DELAYED pain
blood clot normally provide protective layer and when not there exposes bone and nerve endings in socket .:. pain
risk factors for dry socket
molars, mandible, smoking female oral contraceptive pill LA with vasoconstrictor, traumatic XLA, prior infection, FH previous dry socket
causes of dry socket
normal clot disappears/ doesn’t form
epithlium need to travel down hard tissue instead of forming over clot
often starts 3-4 days after extraction, takes up to 2 weeks to resolve
localised osteitis
symptoms dry socket
dull aching pain- mod to severe
continuous throbbing
keep awake
bad smell/ taste
management dry socket
check for sequestra first.
supportive: reassurance, analgesia, warm salty MW
LA block, irrigate warm CHX or saline, curettage/debridgement to encourage new clot, WHVP (iodine containing- pack with ribbon gauze and suture in) or alvogel
review and change packs
How to achieve haemostasis peri-op
Pressure LA w vasoconstrictor artery forceps diathermy (cauterising) bone wax
How to achieve haemostasis post op
Pressure (finger swab pack)
LA w vasoconstrictor as infiltration/ST/ into socket/swab
diathermy
haemostatis agents- surgicel
sutures
bone wax smeared on socket wall w blunt instrument
forceps/artery clips
How could pagets disease affect denture wearers
incidence
Pagets disease results in enlargement of the maxilla due to over activity of osteoclasts and osteoblasts. normal bone remodelling is replaced by chator bone alteration of bone deposition and resorption with resorption dominating in early stages
incidence: 5% over 55 year olds, mainly men
why are older pts more likely to have caries
polypharmacy
xerostomia induced meds
change in lifestyle after retirement could account for higher caries risk- dietary
radiographic signs on roots of dentition of pagets disease
any other conditions that could causes this
hypercementosis - idiopathic, non - neoplastic condition characterised by excessive build up or normal cementum on roots of one of more teeth
acromegaly
goitre
rheumatic fever
vit a deficiency
Precautions taken when XLA pt on bisphosphonates
Liaise with dr to ascertain if drug holiday can be taken
advise pt of risks with written info and informed consent
advise pt to rinse twice daily with CHX MW 1 week before XLA
irrigate are w CHX immediately prior
Use atraumatic XLA technique
avoid raising flaps
achieve primary closure where possible
rinse twice daily with CHx for 2 months post op
refer to specialist if required
What does RPI stand for
+ mechanism of function
occlusal rest, distal guide (proximal) plate, gingivally approaching I bar clasp
saddles sinks into denture bearing area, rotation about mesial rest, distal guide plate and I bar rotate downwards and mesially, disengage from tooth, torque forces avoided
i bar disengages as moves down into undercut region as axis of rotation around mesial rest .:. less force on tooth
factors to increase stability in RPD
retention indirect retention bracing strong connector even distribution of rests
= obtained by all
the factors which provide support, retention,
reciprocation, bracing, indirect retention,
occlusion, and connection. and correct function by pt
define: support
resistance to movement of the prosthesis towards the edentulous ridge
define: resistance
resistance to movement of prosthesis away from edentulous ridge along path of placement
define: reciprocation
the means by how forces acting on one part of the RPD are counterbalanced/ counteracted/negated by another part of the RPD
define: bracing
resistance to horizontal forces from mastication and tongue
problems of a) increased ovd
b) decreased ovd
a) increased ovd = decreased freeway space - difficulty speaking, difficulty eating,muscle pain
b) decreased ovd - poor facial profile (collapsed face), generalised facial discomfort, lack of chewing pressure
define: indirect retention
the resistance to rotational forces of a tooth-tissue supported denture and palatal major connector away from the denture foundation area when occlusal forces (e.g sticky foods) are applied to denture base
define: stability
the resistance to movement of a dental prosthesis due to functional forces
What can occur with a Upper complete and partial lower?
combination syndrome- when maxillary complete denture occludes against mandibular RPD with distal extension- severe anterior maxillary resorption combined with hypertrophic and atrophic changes in diffferent quadrants of maxilla and mandible
indications for copy dentures?
- replacement of immediate dentures
- spare set
- wear of occlusal surfaces
- loss of retention in otherwise favourable dentures
- polished surfaces good and correct position of teeth
define neutral zone?
zone of minimal conflict of muscular displacing force
technique for copy dentures
Visit 1
• Four upper plastic disposable stock impression trays are selected and silicone adhesive
applied to the inner surfaces of two and the outer surface of the other two trays.
• The dentures to be copied are cleaned, disinfected and dried. An appropriate amount of
polysiloxane impression putty is mixed and placed in one of the trays with the adhesive
on the inner surface.
• The denture is inserted occlusal surface down, and putty manipulated to within 2mm of
the periphery.
• When set, petroleum jelly is applied to the exposed putty, for ease of separation of the
two halves of the mould. A second mix of putty is then manipulated into the fit surface
of the denture and an impression tray with adhesive on its outer surface, positioned on
top of the putty. The residue is wrapped around the tray.
• When set, the mould is separated and the dentures removed.
• The dentures are cleaned and returned to the patient.
Visit 2.
• Check that the templates have no voids or rough edges.
• The templates are effectively used as special trays. They are modified with greenstick
impression tracing compound to correct under-extension and to ensure properly
moulded peripheries. Working impressions are taken in a light bodied silicone or zinc
oxide eugenol impression material. The jaw relationship can then be recorded together
with any modifications to the occlusal vertical dimension, with wax or bite registration
paste and a tooth shade taken.
Then the same as usual.
factors to check at trial stage
extension retention stability occlusal planes occlusion aesthetics and speech position of teeth occlusal height ovd / freeway space centre lines
Knife edge ridge management for lower complete denture
impression technique: take impression firstly as normal. then roll finger along ridge to identify areas of discomfort - check for grimace, then cut relief in imp and take again with mucostatic impression material e.g light bodied PVS
put soft lining material on knife -ridge area
surgery: to smooth ridge down
indications for shortened dental arch
sufficient healthy teeth good periodontal support pt acceptance reasonable aesthetics function
Correct posterior extension of an upper and lower denture?
maxillary- impression extends to hamular notches and 1-2mm anterior to palatine fovea
mandibular- extends to retromolar pad and vestibular sulcus
3 ways to assess vertical dimension
willis gauge, callipers, check speech, visually with ruler and dots
2 ways to assess position of maxillary anteriors
labial profile, alma gauge, centre lines
alma gauge - defines position of anterior centrals incisors
pt missing 48,47,46,45,36,37,38. design rpd
support: rests on 44m, 43d (cingulum), 35m, 34d
retention: gingivally approaching i bar clasps 35 + 44. rests on 33 + 32 cingulums
proximal plates 44d and 35d rpi design
connector: lingual bar if 8mm space, lingual plate if not.
space needed for lingual bar and why
8mm
3mm clear of gingival margins, 4mm depth of bar, 1mm from sulcus floor
what concerns do patients have about use of amalgam?
+reassurance you can give
colour, mercury leaching, allergy , oral cancer, tooth wear, longevity, cost
reassurance: mercury within compound so non-toxic, minute amounts, clinical evidence, good longevity, no definite link to cancer, WHO
Steps of cavity prep
1 outline form 2 resistance and retention form 3 convenience form 4 removal of remaining caries 5 finishing of cavity walls
principles of outline form (first step of cavity prep)
all fault or caries removed
all friable or weakened enamel should be removed - avoiding marginal ditching
all margins placed in a position to afford good finishing of margins of restoration- giving cavosurface angle correct angulations according to restorative material ( 90 degree for amalgam, obtuse for cast gold)
rules for outline form
rules-
1 extend to sound tooth structure
2avoid terminating the margins on extreme eminence e.g cusp height or ridge crest
3if extension include 2/3 of cusp incline, cusp capping is done for non adhesive restorations
4 extend prep margin to include all fissures that cannot be eliminated by enameloplasty (shaping of fissures to be non retentive)
What is resistance form of cavity prep?
refers to the design features in cavity prep which allow tooth and restoration to resist the masticatory stresses without fracture
90 degree csa
walls parallel or perpendicular to forces
rounded line and point angles
flat and smooth walls
What is retention form of cavity prep?
refers to design features in cavity prep which allow it to retain restoration securely during function
wall convergence (undercuts)
increase length of wall - to increase frictional retention
axial retentive design features (where base of box is larger than top of box)
risks of ortho
decal
root resorption
relapse
gingival recession
how long ortho on for
18-24 months
4-6 week visits
how to prevent decal during ortho tx
good oh
f-
good diet
ap class skeletal pattern
class 1: maxilla 2-3mm in front of mandible class II: maxilla >2-3mm in front class III: maxilla <2-3mm in front of behind
Convenience form features?
those that improve visibility and accessibility during prep and restoration
Finishing principles of cavity prep?
Noy’s principles -
- enamel should rest on sound dentine
- enamel rods forming CSA must have their inner ends resting on sound dentine
- CSA beveled and covered by strong restoration
What aspects of cavity prep ensure
i) caries adequately removed
ii) finished restoration margins are cleansable
i) access through enamel, removed infected, affected enamel and infected, affected dentine, clearing ADJ
ii) no unsupported enamel, contact point cleared width and depth, do not finish on contact point occlusally
Describe the mechanism by which resin composite is bonded to dentine
Etch - 37% orthophosphoric acid, demineralises dentine surface, widening dentinal tubules and exposing collagen fibrils.
wash then dry
prime- invades space created from etching with primer monomer by displacing water by solvent. has a bi-functional coupling molecule = both hydrophobic and hydrophilic.
Bond- unfilled resin monomer, infiltrates spaces occupried by primer, creating hybridb layer which when cured forms strong cross linked bond to dentine. Includes resin tag creating micromechanical retention. air inhibition of surface layer leaves unreacted monomer to subsequently bond with incrementally build up composite.
post materials (6)
resin, cobalt chrome, type IV gold, carbon fibre, ceramic, stainless steel
length of post requirements
post extends beyond alv bone,
3-5mm gp remains in root,
post is at least as long as height of crown being fitted,
1/2-2/3 of root length
bonding agents
bis-gma (med chain length)
udma (short chain length)
tegdma ( long)
3 methods for removing fractured post
- gonon kit - corkscrew like, remove restorations, force to split post from tooth, mandrel screwed in and extracting forceps used
- masseran kit - hollow trepans of differing sizes- to cut around obstructions in root canal
- ultrasonic vibration
how to check for debonding of adhesive bridge
floss, prove, press and check for flexion
alternative tx for bridge
rpd, implant, nothing, ortho,
factors affecting implant
smoking perio status monetary status alternative tx options pt motivation mh consent
reasons for MOD amalgam fracture
pt factors- parafunction clinician factors: secondaring caries due to poor prep .:. internal stresses, poor compaction, curing or inadequate isolation imperfections in material residual monomer present occlusion not corrected
tx options for fractured large mod amalgam
remove restoration and re-restore
direct restoration or indirect
overdenture
xla
causes of erosion
i) intrinsic - gord, vomiting, anachlasia, alcohol intake induced reflux
ii) extrinsic - acidic juices, occupational exposure, diet
4 types of wear
erosion
abrasion
attrition
cervical abfraction
factors needed for diagnosis of wear type
location of tooth wear history diet analysis toothbrushin habits clenching/grinding presentation (cupping/fragmented)
Causative factors for wear
diet habits drugs xerostomia mh parafunction tmd
tx for wear
ohi diet advice address habits/ parafunction, restorative, occlusal adjustment splint fluoride
CASE
discoloured 21, 20 yr old male, exacerbating over 2 years. good pdh and pmh nil
aetiology
local factors to consider
5 restorative options
aetiology:
intrinsic- pulp obliteration, internal root resorption, external root resorption, caries, plaque/ calculus
extrinsic- diet,smoking, tanins, chx
local factors: trauma history, diet, smoking, tanins
tx: external/ internal bleaching, direct comp, veneer, crown, micro/macroabrasion
factors to consider in bridge placement and design
space available abutment selection support type of retainer aesthetics type of pontic colour occlusion (space for pontic)
factors to consider in implant assessment
history: pt motivation, hard and soft tissue availability, perio health, dentition, occlusion, available interdental and interocclusal space, mouth opening
smoking, untreated perio = no implant
lip and smile line
mh- poorly controlled DM, immunosuppresion, scleroderma, bisphosphonates = incrs. risk of failure
rads: quality & quantity bone, any bone path
difference between reversible and irreversible pulpitis
reversible has a sharp shooting pain on hot/cold stimulus, stops when stimulus removed whereas irreversible has a spontaneous dull ache pain which persists after removal of stimulus, keeps awake at night.
Reversible responds to EPT an ethyl chloride, probably hyperreactive. irreversible has hyper or hypo response to sensibility testing
how to: evaluate post and core clinically and w/ rads
clinically: looking for visible or felt margin defects to check coronal seal
rads: length, position, radiolucent areas, opacity of root, gp left, condensation of gp
what is dentine hypersensitivty
pain arising from exposed dentine in response to a thermal, tactile or osmotic stimulus.
due to dentinal fluid movement stimulating pulpal pain receptors
diagnosis through elimination of other causes
tx of dentine hypersensitivty
eliminate or reduce aetiological factors (i..e improve ohi, toothbrushing instruction, elimination of extrinsic and intrinsic erosive factors)
decrease permeability of dentinal tubules - tp containing strontium/ f-, f- varnish, dentine de-sensitisers, dentine adhesive system or restoration
MCC crown prep dimensions
2mm working cusps, 1.5mm non working, 1.5mm shoulder aesthetic
0.5mm chamfer for metal
CASE
pt lost crown/bridge what would you do
provisionalisation-
to provide aesthetics, function, occlusion, gingival health and contour,
can fabricate directly or indirectly -
direct: matrix (impression and vacuum form) or shells or free hand
indirect: putty index of diagnostic wax up on study model
describe indirect fabrication of provisional restoration
- take putty index of diagnostic wax up on study model
- carry out your intra oral crown prep
- take alginate impression of crown prep
- pour impression in quick setting stone to make a stone model of prep
- fill putty index with PMMA and seat it on the stone model to fabricate provisional crown
- once set, remove from model and modify/ trim fabricated provisional crown as required
pema pmma bis acrylic composite
provisional materials
read this paper https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5830998/
undertsnand diff materials and uses and pros and cons
