measuring caries Flashcards
What is the Pitt’s caries iceberg?
Stages of caries
Above surface- lesion in pulp, cavity into dentine
Trickier below- cavity in enamel etc, enamel lesion w intact surface, detectable only w aids, sub clinical initial lesions
Why measure caries for research?
~Assess disease levels in a group
~Give insights into how prevention works
~Assess effectiveness of prevention (individual/community)
Why is caries diagnosis in an individual difficult?
Mouth- dark, wet and mobile, small opening
Early changes subtle
More difficult at lower caries
More difficult in presence of fluoride (remin on surface but not underneath)
Commonest sites difficult to access
Consequences of incorrect diagnosis/technique severe
Why is caries diagnosis in a community difficult?
Diagnostic agreement between dentists/DCPs is poor
One practioner has different diagnoses at different times
Consequences of incorrect dx-
~over/underestimate disease
~miscalculate effectiveness of interventions
~misdirect resources
How do you diagnose caries?
Visual Tactile Radiographs Transillumination Electrical techniques Lasers/other tech
How do you do a visual exam?
Time honoured
Rigorous training and calibration
Requires good light, dry and clean, mouth mirror and magnification
Can use temp separation
How do you do a tactile exam?
For difficult to see
Blunt explore passed gently over surface as-
-soft enamel lesions can remineralise
Over dx can occur if you wedge explorer into pits/fissures
How do you use radiographs?
Good for proximal Poor for occlusal Computer aided techniques Use as low as reasonably practical -ALARP Not ethical/useful in epidemiology
How do you use transillumination?
Demineralised tooth absorbs more light- so darker Fibre-optic transillumination FOTI since 1970s Digital enhancement Better than radiographs for occlusal
What is Midwest caries ID?
Uses red and infrared LEDs and fibre-optics
Reflection/refraction of light detected and converted to electrical signals- computer algorithm
At least as effective as other methods
What are electrical techniques?
Sound enamel- high electrical resistance (DC) or impedance (AC)
Mixed freq devices can detect occlusal and proximal
Technique sensitivity, impacted by saliva and temp changes
How do electrical techniques work?
Electrical conductance-
~demin creates porosities which fill w water and ions form saliva/ this changes conductivity
Electronic conductance monitor-
~Single AC current measures impedance of tooth tissue
Conductance test uses spectroscopy- multiple freq spectrum AC
What are other methods of detection?
Endoscopes, intra oral cameras/monitors
Lasers- quantitative laser fluorescence, DIAGNOdent- measures fluorescence of tooth
Optical coherence tomography- light based, cross sectional image
Monoclonal antibodies- specific detection
What evidence base is there?
Cochrane reviews 2021
Better studies needed and more results to come
What is the DMF index?
Decay, missing and filled teeth DMFT, 1938
Summarises caries and treatment experience in groups
OR DMFS (surfaces)
dmft for deciduous
DMFT for permanent
Calculate score for individuals and aggregate
How do you score the DMF?
DMFT- Total of decayed, filled, missing teeth
You don’t score a tooth in more than one category
DMFS- Total of decayed surfaces, filled surfaces and missing teeth
Why do the DMF index useful?
Summarised as population mean and proportion of ‘caries free’ (DMFT%=0)
Long history of use for comparisons
Simple to understand
Underestimates total caries experience t
How do we use the DMF Index?
- Deans 21 cities study
- Charting decline in caries (proportion of 5yr olds w obvious decay)
- Comparing caries geographically (using maps)
- Identifying cause and determinants of oral health
What is the Deans 21 cities study?
Compared levels of caries an fluorosis in 21 US cities in 12-14 year olds
Cities had varying levels of naturally fluoridated water
Set optimal level for water fluoridation (1ppm, now less)
What are the problems with DMFT?
Difficulties of caries diagnosis remain
Cumulative and irreversible (high DMF maybe due to caries in past and age specific)
~less useful in adults as data becomes saturated
Doesn’t distinguish between treat and untreated decay- no indication of benefit
Doesn’t distinguish between severity of disease- tiny occlusal cavity same as extracted tooth
Doesn’t record secondary caries/replacement restorations
Aggregates caries and treatment experience
Can’t distinguish between other tooth extraction reasons- ortho etc
Doesn’t tell anything about impact of caries on person
What is ICDAS?
ICDAS- international caries detection and assessment system
Aimed to identify early non cavitated lesions and encourage prevention
Links w management
Used for individual patients
Too long for epidemiology
DMFT still used by WHO (well established, simple and quick)
~historical and international comparisons
How is ICDAS measured?
Code 0-6
Sound tooth- extensive (more than 1/2 surface)
