06/04 Flashcards
Role of fluoride
- incorporates into tooth to form fluoroapetite, which is more caries resistant than hydroxyapetite
- inteferes with adhesion of bacteria
- promote remineralisation
- make enamel more resistant to acid
How to identify caries?
- clinical detection
- dry tooth
- good light
- sharp eyes
- fibreoptic transillumination
- caries detection dye
- radiographs
- sensibility and vitality test
7 caries risk assessment (SIGN 47)
- medical history
- social economical status
- salivary flow
- fluoride use
- diet
- clinical evidence
- plaque control
Biofilm development
- adhesion/ attachment - bacteria attach to the pellicle via fimbriae, this is initial reversible adhesion
- colonisation- primary colonisal provide new binding sites for adhesion by other oral bacteria, firm irreversible anchorage
- maturation- development of micro-colonises and eventually to a mature biofilm
- climax community
- dispersal- dispersal of microbes to
Fluoride toxicity
- fluorosis
- impaired growth of apatite crystals
- retain matrix proteins
- increase binding of proteases
How does calcium fluoride work?
- high fluoride content in the mouth, from calcium fluoride
- acts as fluoride reservoir
- works fluoride varnish is applied
Fluoride reservoir
- calcium fluoride
- fluoroapatite
Fluoride
- fluoride varnish
- fluoridated water
- fluoride toothpaste
- fluoride MW
- Toothmousse
What’s in Toothmousse?
CPPACP
- casein phosphopeptide amorphus calcium phosphate
- cannot give pt who is lactose intolerant
Roles of fluoride
- incorporation into enamel crystal to form fluroapetute
- resistant to streptococcus strains
- inteferes with adhesion force of bacteria, reducing ability to stick to surface of tooth
Does fluorosis happen in adults?
- only occurs during development of tooth
- resin infiltration
- ## direct restoration
Toothpaste fluoride toxic dose
- 5mg/kg
Management of fluoride toxicity
BDS 2 lecture
- drink milk
- monitor for a few hours
- IV calcium gluconate (15-64 admit to hospital)
Cavity design of amalgam
- undercuts
- convergent occlusally
- 90-120 degree cavosurface margin angle, buttjoint
- cavity depth 2mm
- isthmus 1-1.5mm, 1/3 width of tooth
Increase retention of amalgam
- undercut
- retentive groove
- dovetail
- reverse s curve
- dentine pin
- metal bonding agent
Cavity design of comp
- bevel joint
- no undercut
- no unsupportive enamel
- no excessive acute angle
- rounded internal point angle
- depth 1-1.5mm
- margin clear of occlusal contact
If caries left at ADJ and restore?
- enamel at ADJ is weak and may break down restorative margin
- unsupported enamel
- marginal integrity is compromised
- caries will spread laterally and towards pulp
Amalgam constituents
- mercury
- silver
- tin
- copper
- zinc - scavenger during production, oxidises and slag formed
Two types of amalgam
- traditional amalgam
- copper enriched amalgam (13-30%)
Gamma 2
GAMMA 2
- weak and poor corrosion resistance
- thin mercury
What is creep?
- when a material is repeatedly stressed for a long period at low stress levels (stress below elastic limit), it may flow, resulting in permanent deformation
- ditching margins
Benefits of Copper enriched
- higher early strength
- less creep
- higher corrosion resistance
- increased durability of margins
Indication of amalgam
- large cavity
- moisture control cannot be achieved
- bruxism patients
- if aesthetics is not a concern
- cheaper
Contraindication of amalgam
- allergy to metal
- contact allergy
- aesthetic
- breast feeding
- under 15 years old
- less conservative