Dental Caries Flashcards
Dental caries - Definition?
- a bacterial disease of the calcified tissues of the teeth characterised by the demineralisation of the inorganic and destruction of the organic substance of the teeth
Dental caries - Acidogenic theory of dental caries? What happens? What’s affected?
What happens:
- result from a metabolic shift accompanied by gradual change in ecology of the dental biofilm
- imbalance in equilibrium between tooth mineral and biofilm fluid develops
- acid produced by oral bacteria from carb fermentation
What’s affected:
- decalcification of hard tissue substance and disintegration of the organic matrix
Dental caries - Aetiology of caries? Primary and secondary modifying factors?
Primary: - morphology - saliva - pH - fluoride - diet - hygiene - immune - genetic Secondary: - socioeconomic - education - lifestyle - environment - age - ethnic group - occupation
Dental caries - Bacterial metabolism? Acquired pellicle? Dental plaque? Defintion?
Acquired pellicle:
- absorbed layer of mainly salivary glycoprots that forms on clean enamel, which bacteria adheres to
Dental plaque:
- biofilm of bacteria embedded in matrix of salivary mucins and extracellular polysacchardie polymers (on all surfaces)
Dental caries - Development of dental biofilms - process?
Process:
- pellicle forms
- attachment of bacterial colonisers (0-14h)
- co-adhesion and growth of attached bacteria leading to microcolonies (4-24h)
- microbial succession leading to increased bacterial diversity with continued adhesion and growth (1-7d)
- climax community/mature biofilm (1 week)
Dental caries - Initial colonisers - types? content? nutrients?
Types: - S.sanguis/oralis and mitis - Actinomyces and Neiserria Content: - 95% strep - 56% total microflora Nurients: - endog molecules of saliva
Dental caries - Microbial succession - early colonisers to bridge?
- from strep dominated to a plaque dominated by actinomyces
- bacteria produce polysaccaride and these contribute to biofilm matrix
Dental caries - Mature biofilm - diverse composition? Organisms reducing acidogenic potential?
Diverse composition: - facultative or obligate anaerboes - +ve bacteria (low pH non-mutans strep, mutants strep, actino and lactobacillus) Reducing potential (organisms) - veillonella app - S.sangius - S.salivarius - A.naeslundii
Dental caries - Cariogenic features of dental biofilms bacteria - characterisitics?
- rapidly transport fermentable sugars
- conversion of sugar to acids
- maintain sugar metabolism under extreme conditions (low pH)
- prod of extra/intracellular polysacc
Dental caries - S. mutans - absence and high level effects?important role?
Absence: - caries can develop High levels: - caries may not develop Important role: - role in caries initiation (lactobacillus for progression)
Dental caries - Lactobacillus - type? characteristics? location?
- pioneer organism
- +ve non-spore forming rod (microaerophillic)
- colonise dorsum of tongue
- progression of caries
- established loss pH increases number of lactobacillus and reduces mutans
- contributes demineralisation of teeth once lesions established
Dental caries - Oral actinomyces - characteristics?
Characterisitics:
- +ve non spore, rods and filament
- good plaque former
- ferment glucose and produce lactic acid
- A. viccosus and A. naeslundii (root caries)
Dental caries - Summary of the microbiology of dental caries - overview? Ecological plaque hypothesis?
- S.mutans resident flora, but very low numbers (high in white spot lesions)
- S.mutans and Lactobacilli does not explain variation in caries experience
- Many acid-prod microorganisms and so no single organism can be attributed to caries
Ecological plaque hypoth: - consequence of changes in balance of resident microflora
Dental caries - Intrinsic factors that influence tooth caries?
- Enamel composition
- Enamel structure
- Tooth morphology
- Tooth position
Dental caries - Extrinsic factors that influence tooth caries?
- Saliva
- Diet
- Fluoride
- Immunity
Dental plaque - resting pH? pH changes with sugar? rate changes?
Resting pH:
- 6.5 - 7
pH changes:
- falls to around pH 5 within 2-3 minutes of rinsing the mouth with sugar solution (20 mins to go back to normal)
Rate changes:
- speed in pH drop indicated of speed of plaque metabolism
Dental plaque - how sugar reduces pH? Critical pH?
How sugar reduces pH:
- dietary sugars diffuse through plaque
- converted to lactic acid, acetic and propionic acids by bacteria
- pH could fall by 2 units in 10 mins
Critical pH:
- 5.5 is the lowest the pH can drop before demineralisation can occur
Plaque - action of bacteria?
Action of bacteria:
- store glucose as glycogen (intracellular store)
- S.mutans synthesise other polymers given access to sucrose
- can synthesise extracellular polymers from simpler sugars
- increase plaque bulk and are more cariogenic
- glucosyltransferase break down sucrose into fructose and glucose, using this energy released to build glucose and fructose polymers
- glucans and fructans deposited extracell providing sticky environment for plaque organism
- ability of microorganisms to form plaque related to ability to synth polysacc
- control targeted at GST
Dental caries - The effect of diet on caries - factors? sugars? sucrose?
Factors:
- plaque composition influenced by diet
- S.mutans greater with high sucrose diets
- lactobacilli is acid tolerant and found in greater proportions in carious cavities and deep layers of plaque exposed freq to sugars
Sugars:
- sucrose, glucose, fructose, maltose, lactose and galactose
Sucrose:
- affects the composition of early plaque, leading to higher numbers of bacterial species capable of synth glucan from sucrose
- plaque bulkier with sucrose-rich diet in comparison
- encourages dextran prod in plaque due to energy released (sucrose broken down into 2 monosacc)
Dental caries - Substitutes to dietary sugars - effects? Xylitol?
- Non-sugar sweeteners are virtually non-cariogenic
- Xylitol though to prevent caries
- Sugarless gum prevent caries by stimulating salivary flow
Xylitol: - affects bacteria growth and metabolism
- affects de/mineralisation
- reduces biofilm form
- decreases S.mutans
Dental caries - Oral pH change - on eating food item?
- Food item containing sugars, rapidly fermented by acidogenic bacteria, rapid acid production, plaque pH will fall
- other items eaten, before, during or after influence pH
- stimulates saliva (raising pH)
- remineralisation may be enhanced by Ca or fluoride (from food)
Dental caries - Key factors for primary dentition caries?
- Sticky products are more cariogenic
- Sweetened pacifiers
- Sweetened drinks in bottles
- Prolonged breast feeding
Fluoride impact on plaque and dental caries?
- High fluoride conc in plaque
- Fluoride favours precip of Ca and Pi
- Ca/Fl apatite encouraged
- Fl-apatite form part of development (if administered)
- Less soluble in acids more stable crystals
- Fl ions inhibit bacterial metabolism
Dental caries - Substitutions in the hydroxyapatite crystals? Effect?
Main substituents of apatite: - HPO4, CO3 for PO4 - Sr, Ba, Pb, Na, K, Mg for Ca - F, Cl, Br and I for OH Ions present may influence ability of formation of dental caries - Fl inhibits cires - CO3 promotes carious attack
Dental caries - Demineralisation and remineralisation of the dental hard tissue - Saliva? dissolution?
Saliva:
- dilutes and budders acid (conc Ca and Pi ions)
Dissolution:
- more undersaturated the plaque fluid, with respect to hydroxyapatite, the greater tendency for dissolution of the enamel apatite
Between pH drops, remineral slowly occurs
Classification of Dental caries - site of attack?
Pit and fissure: - occlusal surface of pre/molars - buccal and lingual surfaces of molars - lingual surfaces of incisors Smooth surface: - below contact points (leads to cavitation) - gingival third of buccal and labial surfaces (wide open cavity) Root: - exposed to environment - reduced periodontium - softened root surface - shallow cavities - may reach dentine - hypermineralised surface - brownish tissue - loss of cementum (dentine caries can start) Recurrent: - around margins or base of existing restorations
Classification of dental caries - rate of attack?
Acute caries:
- rapidly progressing
- all erupted teeth
- rapid coronal destruction (involvement of pulp)
Chronic caries:
- slow
- late pulp involvement
- pulp reaction (sclerosis or reactionary dentine)
Arrested caries:
- become static and show no tendency for further progression
- enamel; interdental lesions arrested when adjacent teeth lost (easier to clean)
- dentine; lesions with early sclerosis limit spread (stained brown colour)
Histopathology - enamel caries - name? shape? orientation? zones? characteristics?
Early lesion - white spot lesion:
- cone shaped with the base on the enamel surface
- apex pointing towards the amelo-dentinal junction
- different zones reflect different degrees of demineralisation
Zones:
- Translucent, Dark, Body and Surface
Histopathology of dental caries - Translucent zone?
Translucent zone:
- advancing edge of lesion
- more porous
- 1% of space (large pores)
- reduced Mg and CO3
- dissolution in interprismatic area (partial or totally missing)
Histopathology of dental caries - Dark zone?
Dark zones:
- 2/4% volumes of pores
- larger and smaller pores than translucent
- remineral due to precipitation of minerals lost from translucent zone
- narrow (in rapid)
- wider (in slow, more mineralisation)
Histopathology of dental caries - Body of lesion?
Body:
- 5-25% pore volume
- larger crystals than enamel
- water and organic materials replace lost materials
- prominent striae of Retzius
Histopathology of dental caries - surface zone?
Surface zone:
- little change in early lesion (no clinical appearance)
- more mineralised than enamel
- minerals from plaque and demineralised deeper layers
Enamel caries - histopathogenesis process?
- subsurface translucent zone
- enlarges and a dark zone develops in centre
- Body of lesion forms in centre of dark zone (white spot)
- Stained (brown)
- Reaching the dentinoenamel junctions, caries spread laterally undermining adjacent enamel
- Critical stage, enamel breaks forming a cavity (can happen earlier)
Histopathology of dental caries - fissure caries? white spot formation?
Fissure caries: white spot formation;
- caries forming on walls of fissure
- spreads outwards to adjacent enamels and downwards to dentine
- lesions meet at base of fissure
- cone shaped lesion with base at dentinoenamel junction
Histopathology of dental caries - dentine caries? contents? reaction? bacteria?
Dentine caries:
- living tissue respond to carious attack
- high organic content can be destroyed
- pulpal reaction before lesion reaches dentine
- demineralisation before bacterial front (bacteria break down organic matrix)
Histopathology of dental caries - dentine caries’ zones?
- Sclerosis
- Demineralisation
- Bacterial invasion
- Destruction
Histopathology of dental caries - Zone of sclerosis? Key defining features?
Zone of sclerosis:
- similar to translucent zone
- beneath and sides of lesion (broader beneath)
- reaction from odontoblasts
- acceleration of peritubular dentine formation
- calcification of odontoblastic process
Key defining features:
- dead tracts
- death of odontoblasts
- air filled
- pulpal cells occlude tracts with hyaline calcified material
Histopathology of dental caries - Zone of demineralisation?
Zone of demineralisation:
- intertubular dentine is affected by acid wave
- acid diffuses ahead of bacteria
- soft dentine and sterile
- can’t be distinguished by infected dentine
- stained yellow (bacteria)
Histopathology of dental caries - Zone of bacterial invasion?
Zone of bacterial invasion: - bacteria proliferate within tubules - tubular walls become soft and distended - liquefaction foci - beaded appearance Two waves: - acidogenic bacteria - proteolytic organisms
Histopathology of dentine caries - Zone of destruction? acute and chronic appearance?
Zone of destruction:
- increased number and size of liquefaction foci
- cracked appear at right angles of tubules (transverse clefts)
- cavitation
- acute (dentine very soft and yellow)
- chronic (brownish black colour and leathery)
Histopathology of dental caries - pulpal reaction? Tertiary dentine?
Tertiary dentine:
- variations in structure
- irregular (fewer tubules, poss atubular)
- varied mineralisation
- delay pulp involvement
Caries - Morphology of fissures - types?
Types:
- V and U type (shallow and selfcleansable)
- I and K type (Deep, narrow and retentive)
Root caries? Defintion? Demineralisation pH
- Root caries is a disease that is expressed as soft, progressive lesion found on a tooth root surface may has lost CT attachment and thereby has become exposed to the environment if the oral cavity
- pH (6.7)
Aetiology of root caries? Demineralisation pH? Factors? Microbiology? Diet?
pH: 6-6.5
Factors:
- less salivary flow, age, institutionalised, oral hygiene and number of teeth
Microbiology:
- strep mutans (coloniser) together with lactobacillus (root caries)
- strep sobrinus (combo mutans)
- strep sanguis (protective)
- actinomyces (a contradiction)
Diet:
- refined carbs and prevalence of root caries
- saccharose (higher pH 》 perio disease treated)
- decreased taste 》 increased sweets
Time
Root caries - active vs inactive? Clinical signs?
Inactive - well defined, dark brown, smooth/shiny surface, hard on probing, no plaque, possible cavitation
Active - yellowish, soft or leathery on probing, visible plaque, possible cavitation
Hellyer et al (1990) texture of lesions? Types?
Hard: as the surrounding tissues
Leathery: penetrated by new Ash 6 probe under mod Pa
Soft: easily penetrated by a new Ash 6 probe under moderate pressure with no resistance
Grading of root caries - Billings classification? Grades?
Grade 1: incipient
- soft texture, can be penetrated with explorer
- no surface defect
- light tan to brown pigment
Grade 2: shallow
- soft, irregular and drought texture, penetrated by a explorer
- 0.5mm depth surface defect
- tan to dark brown pigment
Grade 3: cavitation
- soft texture, penetrated by explorer
- penetrating lesion, cavitatuin present > 0.5mm, but no pulp involve
- light brown to dark brown pigment
Grade 4:
- deeply penetrating lesion with pulpal or root canal involve
- brown to dark brown pigment
Acute caries - Characterisitics? Vulnerable patients?
- rapid process (many teeth)
- lighter in pigment (light brown)
- pulp exposure and sensitive
- childhood/radiation caries
Chronic caries - characteristics?
- long standing involve (few teeth)
- no pain (usually secondary)
- decalcified dentine is dark brown and leathery
- small pulp chambers with addition dense tubular dentine in pulpal wall (tertiary dentine)
- significant degree of sclerosis
Arrested caries - charactersitics?
- static caries showing no further progression
- shift in oral conditions
- sclerosis of dentinal tubules and secondary dentine formation
Occult caries - what is it? Why is it a problem?
- a caries lesions that is located in a deep fissure of a molar, not showing clinical signs in the patient (can’t see, need xray)
- a shock to a patient
Initial caries - defintion?
- demineralisation without structural defect
Superficial caries - defintion?
Enamel caries
Moderate caries - defintion?
Dentine caries
Deep caries - defintion?
Close to pulp
Complex caries - defintion?
Caries led to opening of the pulp cavity
Complexity - based upon?
Number of surfaces
Compound - 2 surfaces
Complex - greater than 2 surfaces
Black’s classification of dental caries - class I -VI?
Class I - affecting pits and fissures on occlusal third and 2/3 thirds of molars and premolars, and lingual part of ant
Class II - prox. surfaces of molars and premolars
Class III - porx. surface of ant. without involving incisal angle
Class IV - affecting proximal surface of ant including incisal angles
Class V - affecting gingival 1/3 of facial or lingual surfaces of ant/post
Class VI - cusp tips of molars, premolars and canines
WHO system of caries classification? D1-D4?
D1: clinically detectable Evans lesion with intact surface
D2: clinically detectable cavities limited to enamel
D3: clinically detectable cavities in dentine
D4: lesions extending into the pulp
ICDAS II caries criteria - how to use? Restoartation codes (0-8)? Caries code (0-6)? Missing teeth (97-99)?
How to use: - a 2-digit code should be used, first of the restoration and sealant code and the sword is the caries code Restoration code: - 0 (not sealed or restored) - 1 (sealant, partial) - 2 (sealant, full) - 3 (tooth coloured restoration) - 4 (amalgam restorations) - 5 (stainless steel crown) - 6 (porcelain, gold PFM crown or veneer - 7 (lost or broken restoration) - 8 (temporary restoration) Caries code: - 0 (sound) - 1 (first visual change in enamel) - 2 (distinct visual change in enamel) - 3 (enamel breakdown, no dentine visible) - 4 (dentinal shadow, not cavitated) - 5 (distinct cavity, visible dentine) - 6 (extensive distinct cavity, visible dentine) Missing teeth: - 97 (extracted, caries) - 98 (missing) - 99 (unerupted)
Diagnostic accuracy - sensitivity and specificity definitions? validity and reliability?
Sensitivity: TP/(TP+FN)
- probability that it indicates vaores when caries is truly present
Specificity: TN/(FP+TN)
- probability that it indicates no caries when caries is truly not present
Validity: correctness
- valid method results in measurement that measure the purpose of the measure
Reliability:
- .ethid that can be reproduced by another examiner getting the identical results
Visual-tactile caries examination - how to approach a caries?
Systematic (consistent)
Good light, clean and dry
Mirror and gentle probing (BPE)
Don’t use sharp probe, can lead to cavitation
Fiber-optic transillumination - how to do it?
- light transmitted from an intense light source
- probe should be brought from the buccal ornlingal aspect at 45° to the proximal surface pointing apically, look for shadows in enamel or dentine
- if a shadow is seen from occlusal surface, may be associated with a caries
- low sensitivity
Tooth separation - what is it for?
- orthodontic elastic separator (2-3 days)
- useful when deciding whether to treat radiographically observed dentine lesion operatively or non-operatively
Laser autofluorescence - DIAGNOdent? wavelength? Role? Values of measurement?
- infrared fluorescence of 655 nm for the detection of occlusal and smooth surface caries
Values of measurement: - 0-13 (no care advised)
- 14-20 (preventive)
- 21-29 (preventive or operative depending on caries risk)
- > 30 (operative care)
Radiographs - types?
- bitewing
- periapical
- OPG
- occulsal
- lateral
Caries-infected dentine - outermost layer of carious dentine - Appearance? Clinical signs? Treatment?
Characteristics: - outermost, irreparable, necrotic zone of destruction Appearance: - dark brown,soft, wet and mushy Clinical signs: - mineral component has dissolved away due to acid attack - collagen matrix has been denatured - bacterial load v high - dentine tubular structure destroyed Treatment: - clinically removed - no repair - poor quality bonding substrate fornadhesibe material to achieve adequate seal
Caries-affected dentine - inner layer of carious dentine - Appearance? Clinical signs? Treatment?
Characterisitics:
- inner layer of carious dentine which can be repaired by the dentine-pulp complex
Apperance:
- paler brien, harder, sticky and scratchy dentine
Clinical signs:
- mineral dissolution still occurs but lesser extent
- collagen still damaged by proteolysis but to a lesser extent so permitting dentine repair
- bacterial load lessens
- dentine tubular structure returns gradually within the depths of this zone
Treatment:
- deepest layer
- hypermineralised translucent dentine
- reparative reactions of the dentine-pulp complex
Prevention of dental caries - prevention and management techniques?
- risk assessment of child and family
- helping family manage dental care
- delivery for preventive care based on caries risk
- choosing from range of caries management available
- delivery of restorative care
- referral and recall
- management of dental neglect
- working with agencies for safeguarding
Prevention of dental caries - risk assessment of patient? Process?
- previous GA’s and restorations in mouth
- siblings with family (diet)
- freq of radiographs
- education and motivation
- anxiety (least invasive strategy)
- infection
- ortho considerations
Prevention of dental caries - oral hygiene instruction?
- parental supervision between 7-8 depending on maturity
- no rinse after brush
- brush 2 a day with fluoride toothpaste
- pea sized tooth paste
- all children provided with personal oral health advice
- standard or enhanced prevention
- fissure sealants on perm molar teeth
- over 2, apply Ba fluoride varnish at least 2 a year
Prevention of dental caries - diet?
- diet diary be given for next visit
- over at least 3 days with 1 weekend
- drink water
- hidden sugars
Prevention of dental caries - dental caries?
- world’s most common disease of children
- most common reason for GA’s for children
- totally preventable with education, diet and brushing
- socioeconomic relation
Prevention of dental caries - getting it right for every child?
- wider social aspects of child health (housing conditions, government policies and funding)
- other health agencies
- childsmile
- SDCEP guidelines
- assessment of child needs if the personal care plan is to be effective in improving health
Prevention of dental caries - care plan?
- parent/carer motivation and responsibility
- patient history
- clinical exam
- caries risk
Prevention of dental caries - assessing the child and family?
- when child enters surgery
- make eye contact
- greet by name
- smile
- talk to the patient too
- gain support of parent and discuss how they can support and encourage child
Prevention of dental caries - factors to consider?
- intellectual, medial, mental, physical and other disabilities
- full medical, dental and social history (help assess motivation and health)
- if concerned contact child’s school nurse, or GP
- dental neglect (child protection)
Prevention of dental caries - social history?
- overnight stays (toothbursh)
- parents work don’t course problems with appointments
- GP practice name, school attended
Prevention of dental caries - clinical exam?
- visual inspection on clean and teeth
- radiographs if possible
- justify for radiographs in notes
- assess pain as priority
- look for sinuses if asympto
- cooperation is necessary to attend further appointments
Prevention of dental caries - assessing tooth brushing?
- clean 10/10
- plaque line around cervical margin 8/10
- cervical third of crown covered 6/10
- middle third covered 4/10
Prevention of dental caries - caries risk assessment?
- use of fluoride
- plaque control
- salivary quantitiy/quality
- medical history
- socioeconomic status
- dietary habits
- evidence of previous disease
Prevention of dental caries - scottish quintiles?
- SIMD - scottish index of multiple deprivation
- 1-3 relatively disadvantaged
- always use RA to form freq of review radiograph and freq of recall
Prevention of dental caries - behavioural management?
- tell show do, behavioral shaping and positive reinforcement, structured time, relaxation, and systemic desensitisation
- use of one or a combo of strategies to facilitate both preventive care and treatment
Prevention of dental caries - preventive strategies - explain well?
- consent, # of appointments, what is being done at each but prepared to modify is unable to accept some treatment or change in caries activity
- refer for relative analgesia for GA
Prevention of dental caries - develop individual action plan to encourage habit formation?
- identify convenient time
- identify a trigger as a reminder
- agree a date to review progress
- agree action plan with child and parent with a food and drink dietary and toothbrushing chart
Prevention of dental caries - encourage habit formation?
Motivational interviewing Explore current practices and attitudes Gain empathy Open questions Affirmations Reflective listening Summarising Elicit change
Prevention of dental caries - brushing with fluoride?
Under 3 - smear Over 3 pea-sized Caries RA Standard 1000-1500 ppm Increased risk 1350-1500 ppm Over 10 2800 ppm
Prevention of dental caries - chemotherapy?
- Cetuximab or denusomab long term
- Inflammation and ulveration of oral cavity and oropharynx major side effect particularly in radiotherapy
- Oral mucositis inhibit effective oral hygiene regimens die to pain and strong flavours
