Measurement of caries Flashcards
Describe caries in terms of demin/ remineralisation
A process of dynamic demineralisation and remineralisation
- Normally Ca & PO3 ions in enamel and plaque fluid in eq.
- At low pH fluid becomes relatively undersaturated and pH ions diffuse out of enamel
How does caries progress?
Process pregresses intermittently
Iceberg of caries
D1 - D4
Methods for diagnosing caries
Visual examination Tactile examination Transillumination Radiographs Electrical techniques
Visual examination
Time honoured
Accuracy improved with rigorous training and calibration
Requires good light, dry and clean teeth, mouth mirror
Tactle examination
Useful for difficult-to-see surface
Blunt explorer passed gently over surface of tooth
-Not creating cavities by probing with sharp probe
-Soft enamel lesions can remineralise if surface is intact, digging probe into surface creates cavity that can’t heal
Radiographs
Long-standing use
Useful for approximal but less for occlusal
Neither ethical nor useful in epidemiology
What reduces X-ray dose?
Faster radiographic film
What improves radiograph accuracy?
Digital and computer-aided techniques
Transillumination
Using mouth mirror on anterior teeth
In posterior teeth using fibre-optic transillumination (FOTI)
Electrical techniques
Fixed frequency can detect occlusal and approximal lesions
Marketed in some countries
Electrical conductance
Demin creates porosities which fill with water & ions from saliva –> electrical conductivity changes
-degree of conductance dictated by properties e.g. porosity, thickness of tissue, hydration of enamel, & ionic content of dental fluids
Electronic Caries Monitor
A device that employs a single, fixed-frequency alternating current, which attempts to measure ‘bulk resistance’ of tooth tissue.
Why is caries diagnosis difficult? (in individuals)
- mouth is dark, wet and mobile with small opening
- early changes subtle
- common sites difficult to access
- consequences of incorrect diagnosis technique severe
- more difficult at lower caries levels and in presence of fluoride
Why is caries diagnosis difficult but important? (in groups of people)
Diagnostic agreement between dentists poor
One dentist makes different decisions at different times
Why are consequences of incorrect Dx in groups severe?
Over-/ underestimate prevalence of disease
Miscalculate effectiveness of interventions
Misdirect resources
Why do we need to measure caries? (in individuals)
Diagnosis in individual px
Why do we need to measure caries? (in groups)
Assess disease levels in group
Identify groups where disease less common
Identify causes of disease
Explain how prevention works
Assess effectiveness of prevention (e.g. fissure sealants, water fluoridation etc.)
What does DMF index do?
Summarises dental caries and Rx experience in groups
Define DMFT, DMFS, dmft
Total of decayed, missing & filled teeth (permanent dentition)
Total of decayed, missing & filled surfaces
Total of decayed, missing & filled teeth (deciduous dentition)
How is DMF index summarised?
As population mean, and population caries free (% with DMFT = 0)
Benefits of DMF index
Long history of use allows comparisons
Simple to understand
Examples of use of DMF index
Dean’s 21 cities studies
Charting decline in caries
Comparing caries
Identifying causes and determinants of oral health
Dean’s 21 cities studies
Compared levels of caries and fluorosis in 21 US cities
Cities had varying levels of water fluoridation
Set optimal level for water fluoridation
Problems with DMFT
Difficulties of caries diagnosis remain
Cumulative and irreversible
Does not distinguish between treated and untreated decay
Does not distinguish severity of disease
Does not record secondary caries or replacement filling
Aggregated caries and treatment experience
Cannot distinguish teeth extracted due to caries or other reasons
Other ways of measuring caries
OHQoL to supplement or replace clinical indices such as DMFT
–capture impact of disease on people’s daily lives
Child perception questionnaire
Adults: Oral health impact profile
