ICP Flashcards
What organisms causes acute ulcerative gingivitis?
Spirochaetes eg treponema
Fusobacterium
Where are oral obligate anaeobic bacteria found?
Root canal and pulp chambers infection
Abscess
Advanced periodontitis
Carious dentine
What is the most prevalent type of fungi in the mouth?
Candida albicans
Which bacteria are found on oral mucosal surfaces
Streptococcus salivarious
Which gram positive cocci are present as commensal flora in high numbers in saliva and on tongue
Facultative streptococci
Which bacteria forms black pigmented colonies on blood agar
Porphyromonas, prevotella - they are obligate anaerobic bacteria and comprise large prop of microflora in dental plaque. Rarely found in health. Isolated from subgingival sites.
What is caries
Loss of tooth substance by metabolically produced acids.
Common in pits, fissures.
What does statherin do
Binds to calcium phosphate to prevent it from precipitating out, therefore maintaining levels of calcium for remin of tooth and phosphate for buffering action.
What are the iatrogenic (drug) causes of xerostomia?
Aspirin- NSAIDS Diuretics eg furosemide Antihypertensive eg atenolol, clonidine. Antiepileptic eg phenytoin (grandmal) Antihistamine eg loratadine
Which autoimmune condition can cause xerostomia
Sjogrens syndrom - causes acinar destruction in salivary gland therefore reduced saliva production = higher risk of infections eg candidiasis and caries
What is a fissure sealant
Material placed in fissures and pits to PREVENT and ARREST development of caries.
It is a preventive * measure.
What materials are used for fissure sealant
Unfilled resin or filled - light/chemically cured.
GIC - when isolation is a problem eg partially erupted teeth in high caries risk child.
SR procedure
Clean - rubber cup, rotary brush, air abrasion
La - if multiple teeth need it, or if caries into dentine.
Rubber dam if la was used or other isolatuon.
Caries removal, minimal, use 330 tungsten carbide, make edj caries free.
Primer - hema containing - bonds to collagen via OH bonds, apply 15s n air dry 5s. Rub it in using microbrush.
Bond, sensitive to light, seals dentinal tubules, apply 15s n air3s, light cure 20s.,
Apply comp resin or flowable comp if cavity too small. Light cure. Check for defects using probe n remove excess.
Apply FS to remaining pits n fissures, occlusal palatal n buccal. 1/3 cuspal incline. Use microbrush. Cure 20s.
Check occlusion
Why is isolation needed for fissure sealant
Cuz the etched enamel is porous and may get contaminated with debris during procedure which will reduce n prevent resin tag formation of composite bond to the enamel.
When is a SR/PRR indicated
When diagnostic methods, visual inspection, and bitewing radiographs have shown that a stained fissure has progressed to a lesion just into dentine. (If has progressed more then will require conventional restoration)
Advantages of air abrasion (aluminium oxide/ sodium bicarbonate particles)
1) no vibrations therefore painless n noiseless
2) doesnt result in a smear layer during tooth prep
3) carious tissue removed without affecting healthy teeth
4) no post op sensitivity
5) no burning smell or micro fractures in teeth tht often occurs with drilling.
6) sealants and fillings bond better to tooth
What are the effects of cavity prep on dentine?
Produces vibrations which may cause shift in pulpal blood flow
Will cause pain due to presence of nerve endings in dentine tubules.
Will cause fluid shifts eg cut dentine causes outward fluid shift n collagen deposition forming a smear layer
Odontoblasts may get displaced into dentine tubules n will die, but if dentine is sterile then new odontoblasts can differentiate from stem cells in pulp.
What is enamel hypoplasia
enamel matrix formation is defective resulting in thinned, grooved, pitted enamel.
Wats hypomineralisation
Disturbance of calcification of enamel whereby it is weak n prone to breakdown. seen alongside hypoplasia but one predominates usually.
Why is calcium hydroxide bacteriostatic?
Cuz its alkaline ph11
Cuz it absorbs co2 which is a metabolic requirement of the obligate anaerobic bacteria that are present in dentine caries and pulpitis
Functions of PDLs
Sensory info
Dissipates masticatory forces therefore protecting the tooth.
Source of stem cells for new bone, cementum, other CT cell types.
What is a periodontal pocket (its different to gingival pocket)
A sulcus that has deepened due to loss of periodontal attachment, the resultant depth will be greater than the normal 3mm.
5 points characterising gingivitis
1) gingival oedema (therefore loss of contour)
2) hyperaemia (therefore bleeding and redness) - excess of blood supplying your gingiva
3) increased gcf flow and containing neutrophils
4) increased lymphocytes and plasma cells in the infiltrate indicate increased severity
5) reversible !
5 points characterising periodontitis
1) similar inflam infiltrate to chronic gingivitis
2) PDL and alveolar crestal bone is lost which may be follower by gingival recession
3) apical migration of junctional epithelium resulting in deeper pocketing more than 3mm
4) tooth mobility
5) irreversible
What are the periodontal indices
- pocket depths
- plaque levels
- attachment loss (cej to base of sulcus)
- bleeding scores
- radiographic bone loss
What is probing/pocket depth
Distance from gingival margin to base of sulcus.
What is attachment loss
Distance (mm) from cej to base of sulcus
What is periodontal disease
Inflammatory reaction to plaque at the gingival margin. Can be classed as gingivitis or periodontitis (periodontal tissues involvement)
What are local risk factors for oral conditions
Root exposure Misalignment of teeth Crowding Restorative margins partial dentures
Systemic risk factors
Diabetes Poor oral hygiene Immunodeficiency Nutritional deficit Smoking Obesity Stress Osteoporosis
Describe HA crystallite arrangement in a tooth.
Along the sides of the tooth the arrangement is less ordered.
Cuspal areas have greater crystallite alignment and order, the greatest alignment is seen in areas that are likely to contact cusps of opposing arch tooth
Fracture toughness - definition
Ability to resist brittle fracture in the presence of a crack.
In enamel the protein films + crystallite alignment contribute to its fracture toughness
What two types of behaviour does the protein sheath around enamel display
1) Polymer like - deforms under load
2) elastic - returns to initial form and position after load is removed cuz in that deformed position it is thermodynamically unstable.
Effect of restoration on mechanical properties of tooth
Decreased fracture resistance
Risk of crack propagation and fatigue failure occurring at tooth restoration interface due to high stresses from masticatory forces.
Where/how is porcelain used n wats the adv n disadv
Post alternative for comp- inlays n onlays (indirect restoration)
Adv = abrasion resistant + more durable + aesthetic
Disadv = wear of opposing tooth + adjustment and polishing is more diff.
What does anisotropic mean
When a physical property is different in different directions/locations of the tooth.
Remember:
Material = homogenous n isotropic
Enamel n dentine = anisotropic at microscopic level
Where is the stress location for non bonded restorations
At internal walls - tooth restoration interface
Where is the stress location for bonded restorations
At cusp tips like a normal tooth
Where will cracks occur in bonded n non bonded restoration
Bonded - within enamel in contact with opposing tooth
Non bonded - internal line angles and edj
Wats the optimised shape for reduced cusp tips for onlays/inlays
Perpendicular to the opposing load but not perpendicular to long axis of tooth.
Ideal restoration of a cavity:
No sharp edges or corners
Perfect contact between tooth and restoration
Base of cavity larger for retention
Stress is uniform n minimal at internal line angles.
Internal outline features:
90 degrees cavosurface angle
Lateral wall undercuts
Rounded pulpal line angles
0.5 mm into dentine (deciduous tooth restoration)
How wide shod the cavity isthmus be
1/3rd of width of occlusal table
Wat are the indications for SSC - 7
Special needs patient with reduced OH
2 or more carious surfaces
Extensive one surface caries
Developmental problems eg hypoplasia, AI,DI.
Fractured primary molar
Extensive tooth surface loss - erosion, attrition, abrasion
High caries risk patient
2 contraindications to ssc
If primary molar is close to exfoliation with more than half of root resorbed - seen on radiograph
Nickel allergy/sensitivity
Whats the Hall Technique
Method of managing carious molars in which decay is sealed under preformed metal crown (PMC) without any LA, caries removal or tooth prep.
What is primary prevention + examples
Stopping disease starting in the first place by keeping teeth healthy
- fissure sealant
- f toothpaste
- brush twice daily 2mins n dont rinse
- 4 sugar attacks - limit intake n freq
Whats secondary prevention n examples
Detection n Limiting impact of disease at an early stage
Bitewing radiographs
Occlusal caries - restore/SR
Aproximal/smooth surface - if only in enamel then increase fluoride, reduce sugar, increase brushing
Whats tertiary prevention
Restoring the function of the tooth n preventing further development of disease
- all of secondary
- restore decayed tooth
- extract teeth with poor prognosis
What are the stages in periodontal disease progression
Health Initial lesion Early lesion - early G Established lesion - chronic G Advanced lesion - chronic P
What is MMP n give an example n where are they found in periodontitis
Matrix metalloproteinases
Eg collaginase
Found in high numbers in gcf in periodontitis
Explain function of RANKL and OPG in periodontitis
Cytokines plus bacterial factors increase expression of RANKL which then allows osteoclast formation and activity + decreased expression of OPG in osteoblasts resulting in decreased inhibition of osteoclast activity = imbalance in bone remodelling resulting in increased bone resorption
Describe periodontal probing
Holding the probe in gingival sulcus, parallel to tooth surface and keep in contact as you walk it around the circumference of tooth
Whats BPE for
Simple rapid screening for those at risk of periodontal disease.
Disadv of bpe
No distinction between true/false pockets
No detail about recession
Lack of detail within sextant
No detail abt furcation involvement
How much pressure is used when probing
20g
Define horizontal bone loss
When the bone level lost is equal interdentally
Define vertical/angular bone loss
One tooth has lost more bone than the adjacent tooth, hence alveolar crest is more apical to CEJ for one tooth than the other.
State the order or cariogenicity of sucrose, glucose, lactose, fructose
Sucrose> glucose> fructose> lactose
How can we compensate for xerostomia
Chlorhexidine gel - antibacterial
Topical F
Contraindications of fluoride varnish
Ulcerative gingivitis
Stomatitis
Contraindications of fissure sealant
Partially erupted
Caries present
No risk
Unable to isolate (?)
Whats the criteria for a moderate risk caries patient
1-2 lesions per year
Criteria for high risk caries patient
3+ lesions per year
Medically compromised
Social risk factors
Ortho treatment
What is parafunction
Use of a body part eg tongue/teeth in a way that isnt commonly used eg bruxisn
What is diagnosis
Identification of an illness based on signs and examination
Prognosis?
Prediction of most likely outcome of a disease
What enzyme breaks down ester LAs in blood.
Pseudocholinesterase
Name constituents of LA cartridge
LA Vasoconstrictor - adrenaline/felypressin Preservatives - uncommon in recent LAs Isotonic solution Reducing agent- prevents adrenaline from oxidising
Adv of adrenaline as vasoconstrictor
Vasoconstrictor
Reduces and controls blood flow, less bleeding, therefore increased visibility
Less systemic absorption, lower toxicity, can use higher doses
Prolonged duration of action
Disadv of adrenaline in LA
Increases cardiac output - increased HR and Stroke vol- can lead to arrhythmia
Decreases plasma potassium = arrythmia
Heat and light sensitivite - breaks down
Dont giv to unstable angina and uncontrolled arrythmia patients.
Contraindication of felypressin
Pregnancy - can induce labour.
