Plaque related diseases - caries Flashcards
what is dental caries?
a disease of the mineralised tissues caused by action of microorganisms on fermentable carbohydrates
1st - demineralisation of the mineralised portion
2nd - disintegration of organic material
what factors contribute to caries?
plaque - smutans and lactobacilli
carbohydrates
time
susceptible tooth
when do you treat caries operatively?
visible cavitation
caries close to EDJ
what is NDIP 2003?
national dental inspection programme
p1/7 children have a basic inspection annually and detailed inspection biannually
at what age do bitewings start?
start at 5 years
lateral obliques if no co operation
what are rampant caries?
caries involving several teeth and occur rapidly
how does caries progress?
episodically
enamel has a dynamic surface - constant remineralisation and demineralisation
what happens when caries reaches dentine?
pulp dentine complex reacts to initiate protection of tooth vitality
- bacterial toxins through tubules = inflammatory reaction in the pulp
= reactionary dentine and sclerosis, reduced permeability of tubules and the pulp retreats
what is the aim of a restoration?
remove the bacterial infection before carious exposure
what does pain indicate?
a pulpal inflammation
what does reversible pulpitis require?
remove infection and restore
what does irriversible pulpitis require?
leads to pulpal necrosis - xla,rct
what happens when toxins go through the root apex?
perriradicular periodontitis = abscess, swelling/sinus
what is cellulitis?
soft tissue swelling
what is ludwigs angina?
progresison from severe cellulitis
fom swelling and elevated tongue - difficulty swallowing, eating and breathing
risk of death by asphyxiation
what is primary root surafce caries?
below cej, no enamel involvement/restorations
what is secodary root surface caries?>
adjacent to restoration
what are root surface caries influenced by?
saliva fluoride oh diet chx
what are NME’s
caries epidemic cause
sucrose, glucose, fructose
what are milk sugars?
intrinsic sugars?
lactose
in fruit and veg
what does pre eruptive F cause?
wider fissures
more rounded cusps
thinner enamel and denitne
what is post eruptive F effects?
if f present = fluoroapatite = remineralises
fluoroapatite less soluble than HA
increases enamel mineralisation
increases resistance of enamel to demineralisation
reduced acidity of plaque
what is the conc of F in water?
1ppmF /1mg F per litre
what is duraphat?
5% sodium fluoride
22600ppmF
what is combined fluoride therapy?
gives best results
1 systemic and 1 topical
what is fluorosis?
enamel hypoplasia
white chalky spots/brown staining and pitting of teeth
increased f affects the enamel matrix formation and impairs ameloblastic function
bilateral symmetrical distribution
what is the tx of fluorosis?
microabrasion
bleaching
resin restoration
veneers
what is toothbrush abrasion?
abnromal loss of tooth structure bc non masticatory physical action - repetitive mechanical habit
what is chlorhexidine?
0.2% chlorhexidine gluconate
antiseptic/antimicrobial action
bacteriocidal and bacteriostatic
= adsorbed onto teeth and mucosal surfaces and releases bacteriostatic concentrations over a period of time
how much saliva is secreted daily and what is its function?
0.5-0.6 litres/day
protective, digestive, enamel stabilisation
buffers and neutralises acids
what is xerostomia?
reduced salivary production meds - diuretics, antihistamines, antidepressants radiation s.gland surgery systemic disease - sjogrens syndrome
how does xerostomia look in the mouth?
dry glossy atrophic mucosa
fungal bacterial infections common
angular chelitis
what is the tx of a disabled pt with caries?
superbrush
modified handle
sponges with chx and chx gel
what is moisture control used to eliminate?
saliva
gcf
bleeding
pus etc
what is a PRR?
min pit and fissure caries
restores caries and seals rest of fissure pattern
what problems does NCTSL cause?
sensitivity cupping lesion pulp exposure loss of vitality proud restorations reduced height of crowns aesthetic problems
what is erosion?
chemical dissolution of hard tissues not including bacteria
what is attrition?
loss of structure bc mechanical action of mastication
what is abrasion?
friction
what is abfraction?
tensile/compressive forces during tooth flexure = loss of tooth surface
why might a restoration fracture?
secondary caries
heavy filling
weak tensile tooth structure
what does staining around a composite suggest?
secondary caries
how to diagnose an approximal lesion?
floss and probe
ortho seprators, transilluminate, radiographs
what is an electronic resistance measurer?
sound tooth - insulates
carious tooth - current passage allowed
vanguard similar
what is transillumination?
digital imaging fibre optic
transillumination
approx lesions
what dyes are used for caries detection?
carious detection agents
stains demineralised not infected
what is laser fluoresnce/diagnodent?
early caries diagnosis
caries alters fluoresence
low reading = sound tooth
what is air abrasion?
aluminium oxide particles
what does the stephan curve show?
rapid drop in plaque pH by speed microbes metabolising sugars
slow rise - acid diffusing out of plaque by action on saliva
15-40mins recovery time
what governs the shape of the stephan curve?
saliva
dilutes/clears metabolites and buffers
what is the action of xylitol?
raises intra oral pH bc salivary flow increases/buffers
inhibits adhesion, growth and metabolism of microorganisms
- suppresses S mutans
- remineralises
- synergistic with F
what is the tristan da cuhna study?
before 1940 - low sugar diet
after 1940 - sugar introduced and caries increases
what is the hopewood house study?
dental exams between 1947-1962
lactoveg diet with little or no sugar
no oh/f
low caries rates
what is the vipeholm study?
sweden 1945-1953 study on mentally handicapped pts
high sugar levels associated with small caries increase if taken 4x daily with meals and no sugar in between
sugar between meals = increased caries
what does cheese after sugar do?
prevents depression of plaque pH because increased salivary flow
what does excessive fruit consumption cause?
caries and erosion
bacteria on the surface of teeth is affected by what antibodies?
secretory - from saliva
serum - from GCF
a caries vaccination is being developed against what bacteria?
s mutans
how does fluoride make apatite crystals less soluble?
becomes fluoroapatite which is less sol
displaces carbon and magnesium and improves crystalline structure and reduces solubility
how does fluoride affect remineralisation?
reduces the less soluble carbonate
acid attack = f released which favours remineralisation
f accumulates in early lesions and reduces solubility
how does fluoride affect morphology?
wider fissures
more rounded cusps
thinner enamel and dentine
how does fluoride affect plaque?
enzyme inhibitor/affects metabolism by -
binding to plaque in high concs
inhibits metabolic pathway and acids are not formed
at what ppm is water fluoridated?
how much of the UK has it?
how effective is caries reduction?
1ppmF
15%
20-40% caries reduction
what is in fluoride tabs, how effective are they?
40-50%
NaF
what ppm is fluoridates salt?
250mg
what ppm is milk?
0.03ppm
a high reg intake of F at what ppm causes skeletal fluorosis?
> 8ppmF
what is the lethal overdose of F?
5mg/kg per body weight
describe enamel structure?
core - tightly packed HA crystals
sheath - less well packed, spaces - water and organic material - easier acid diffusion
where demineralisation starts
what are the layers of a carious lesion?
surface zone
body lesion
dark zone
translucent zone
describe the surface zone?
intact, higly mineralised
F content high
small porosity
forms and reforms
describe the body of the lesion?
largest
25-50% porosity
radiographically seen
describe the dark zone?
5-10% porosity
large and mall pores
demineralisation and remineralisation occurs
describe the translucent zone?
1st carious change
1-2% mineral loss
few large pores
what is arrested caries?
remineralised caries
brown exogenous staining
why does cavitation occur?
demineralisation and bacterial invasion
what is the defence respone of dentine?
reactionary tertiary dentine
translucent sclerotic dentine - blocks tubules
what happens in dentine if there is rapid carious progression?
no sclerosis/odontoblasts die and there is poss reparative dentine
what are the zones of a lesion in dentine?
zone of destruction
zone of bacterial penetration
advancing front of dentine
what is the advancing front of the lesion?
zone of demineralisation
acid and no bacteria
what is the zone of bacterial penetration?
bacteria in tubules
lateral spread
lactobacilli
what is the zone of destruction?
proteolytic enzymes
destroys organic matrix
what are the 2 zones of dentine caries?
outer - infected, irriversibly demineralised dentine, proteolytic degradation of collagen matrix
inner - dentine reversibly attacked, collagen not severly damaged, minimal infection
what is the initiation of the carious process?
suscpetible tooth and pellicle formation - colonisation in 0-4 hours, s sanguinis, s oralis s mitis
what is microbial succession of the enamel pellice?
strep to actinomyces in 1-14 days
what makes bacteria cariogenic?
acidogenic : sugars to lactic acid
use extracellular and intracellular polysaccharides into acid
aciduric - thrives at low pH
what is the specific plaque hypothesis?
300 species of bacteria - limited number involved in carious process
what is the non specific plaque hypothesis?
caries happens because of the all over effect of bacteria
what is the ecological plaque hypothesis?
environment influences action
what is the critical pH?
pH of 5.5
HA dissolves below
what are nutritive sweetners?
sorbitol, mannitol,xylitol
bulk sweetners, slowly fermented, only slight pH drop
what are alternative sweetners?
saccharin, aspartme, acesulfame K
intense sweetners
what are tooth friendly sweets?
dont cause pH to fall below 5.7 in 30 mins of ingestion
what can sodium lauryl sulphate be the cause of?
apthous type ulceration
when can GI be used for fissure sealing?
limited co operation
highly anxious
partially erupted teeth - less moisture control
but - wear easier, fall off more often
what is the critical pH of fluorapatite?
4.5
what did dr fredrcik mcKay discover?
1901
pts had mottled teeth
colorado brown stain
what did dr trendley dean discover?
examined caries in 21 cities in america
F levels in water
what is DMFT?
decayed missing filled teeth
what is Def?
count of primary teeth - decayed/extracted due to caries
what is DMFS?
decayed missing filled tooth surfaces
