What is caries? Flashcards
How would you describe caries as a disease?
Dynamic
How is the caries disease process initiated?
When tooth surface is exposed to acids produced by fermentation of sugars in cariogenic bacteria
What happens when pH is lower than 5.5 in enamel? What will this appear as clinically if continued exposure?
Calcium and phosphate ions are lost from enamel crystals. White spot lesions.
What do white spot lesions eventually lead to?
Cavitation
Why is caries described as infectious? How is different to other infectious diseases?
Because it is caused by bacteria colonising tooth surfaces. Result of imbalance of indigenous oral biota rather than an exogenous pathogen.
Are treatments solely restorative?
No, comprehensive treatment programme necessary to manage patients.
Why is a caries risk assessment important? What should be considered about carious teeth?
To determine how often patient needs to visit dentist. Consider if caries is arrested or active.
What are the 4 factors of caries?
Time, substrate, tooth and flora
What is fundamental to the diagnosis of caries? (2)
That tests are valid and reliable; inter-examiner reproducibility
Why is diagnosis of caries important?
1) Basis of treatment decision
2) Informing the patient
3) Advising health service planners (epidemiological survey)
What do P&OCA, PCA and NAC stand for?
Preventative & operative care advised; preventative care advised; no active care advised.
How can caries be scored on a 4-point scale?
\+ = Sound enamel (NAC) D1+ = clinically detectable enamel lesions with "intact" surfaces (PCA) D2+ = clinically detectable caries limited to enamel (PCA) D3+ = clinically detectable lesions dentine (P&OCA) D4 = lesions into pulp (P&OCA)
How might D2+ - D4 be treated?
D2+ may be sealed in e.g. fissure sealants (bacteria would die inside due to lack of O2 and nutrients)
D3+ may be filled
D4 is terminal so root treatment to remove pulp
Which direction does caries spread?
Laterally
Which 4 factors are important for caries detection and diagnosis?
Good lighting
Sharp eyes
Dry, clean teeth
Bitewing radiographs
How does root surface caries appear in its early stages?
As one or more small well-defined discoloured areas near gingival margin
How might lesions vary?
In colour: yellowish/ light brown/ mid-brown/ black
Soft or leathery
Arrested lesions may be cavitated
What is stained dentine?
Affected dentine
In pits & fissure caries, how do these appear clinically?
1) active uncavitated lesions
2) inactive lesions
1) white, often with matt surface
3) may be brown
Are enamel lesions visible on bitewing radiographs?
No
Why are lesions on approximal surfaces usually discovered at a later stage? How are they often discovered?
Difficult to see white spot. Often see pinkish-grey area shining up through marginal ridge (rounded borders that form the mesial and distal margins of the occlusal surface of a tooth)
How can one determine if approximal caries is present?
Tactile - use a sharp probe (Briault)
How does transmitted light help detect caries?
Shines light through contact point. Caries has lower index of light transmission than sound tooth (fibre optics).
Where is transmitted light technique particularly useful? (2)
In pxs with posterior crowding where BWrads will produce overlapping. In pregnant women where unnecessary radiation should be avoided.
How is tooth separation for diagnosis of approximal caries achieved? (3)
Elastic separators forced between contact point to open them up. After 2 days dentist can gently feel with prove to detect cavity. Elastomer impression material can be used between teeth to record cavity if present.
Give 2 brands of laser fluorescence
DIAGNOdent, KaVo
What kind of caries can laser fluorescence detect? How?
Occlusal. 655nm light emitted which penetrates tooth, reflected fluorescnce measured and intensity is indication of size & depth of lesion.
What is the danger with laser fluorescence? How can this be avoided?
Some readings confused by staining & calculus. Should be used combined with BW and clinical visual
What are the 7 caries risk factors?
Medical history e.g. Sjogren’s syndrome (dry mouth) or medications (methadone is full of sugar)
Dental history e.g. multiple restorations
Oral hygiene e.g. toothpaste has no fluoride
Diet e.g. frequent sugary snacks/ drinks
Fluoride e.g. no fluoride supplementation
Saliva e.g. stimulated & unstimulated flow low
Social & demographic factors e.g. low educational status
What are enamel crystals composed of?
HAP crystals packed together into prisms
What happens when minerals are removed from enamel surface?
Inter-crystalline spaces enlarge & become more porous (white-spot)
How does white-spot lesion feel to touch
Matt appearance feels rough with probe
What are the 4 microscopic zones of a caries lesion?
Surface zone (well mineralised compared to body)
Body of lesion (porous and dark)
Dark zone
transulcent zone
What does quinoline soln show and how?
Dark areas of caries on section. Big molecule that cannot get into small enamel holes, therefore appears dark
How does dentine defend itself against caries?
Tubular sclerosis
Odontoblast can form tertiary dentine at pulp-dentine border in response to stimulus
Makes it less permeable
How do bacteria in cavity decompose dentine?
By acids and proteolytic microorganisms
What are the zones of dentine caries?
zone of destruction (liquefaction foci increase)
zone of penetration (bacteria invasion)
zone of demineralisation (no bacteria)
How are dead tracts formed in dentine?
If lesion progresses rapidly.
Odontoblasts are destroyed before they can produce sclerotic dentine
What distinct shape is approximal caries typically on radiographs?
Cone-shaped
How would one tell if it is a cervical burn-out?
Radiolucency stops at bone margin
What does the hydrodynamic theory of dentine sensitivity state?
Stimuli leads to displacement of fluid in dentinal tubules. This activates nerve endings present in dentine or pulp
How does NovaMin function?
Reacts with saliva in mouth to form protective layer of HAP on teeth, creating barrier to prevent sensitivity.
Why is calcium hydroxide sometimes used to line deep cavities?
To promote reparative dentine.
How are liquefaction foci created?
Dentinal tubules invaded and then coalesce together
What are transverse clefts?
Penetration of bacteria which traverse at right angles to the tubules along incremental lines of growth
What can clinician do to encourage reparative dentine/ arrest lesions?
Remove bacteria mass and seal it
Allow patient to clean/ OH/ fluoride
What is the environment of the tooth affected by?
Saliva buffering
Fluorides
Food
