measuring caries

Question 1

What is the Pitt’s caries iceberg?

Answer 1

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

Question 2

Why measure caries for research?

Answer 2

~Assess disease levels in a group
~Give insights into how prevention works
~Assess effectiveness of prevention (individual/community)

Question 3

Why is caries diagnosis in an individual difficult?

Answer 3

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

Question 4

Why is caries diagnosis in a community difficult?

Answer 4

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

Question 5

How do you diagnose caries?

Answer 5

Visual 
Tactile
Radiographs
Transillumination 
Electrical techniques
Lasers/other tech

Question 6

How do you do a visual exam?

Answer 6

Time honoured
Rigorous training and calibration
Requires good light, dry and clean, mouth mirror and magnification
Can use temp separation

Question 7

How do you do a tactile exam?

Answer 7

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

Question 8

How do you use radiographs?

Answer 8

Good for proximal
Poor for occlusal
Computer aided techniques
Use as low as reasonably practical -ALARP
Not ethical/useful in epidemiology

Question 9

How do you use transillumination?

Answer 9

Demineralised tooth absorbs more light- so darker
Fibre-optic transillumination FOTI
since 1970s
Digital enhancement
Better than radiographs for occlusal

Question 10

What is Midwest caries ID?

Answer 10

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

Question 11

What are electrical techniques?

Answer 11

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

Question 12

How do electrical techniques work?

Answer 12

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

Question 13

What are other methods of detection?

Answer 13

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

Question 14

What evidence base is there?

Answer 14

Cochrane reviews 2021

Better studies needed and more results to come

Question 15

What is the DMF index?

Answer 15

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

Question 16

How do you score the DMF?

Answer 16

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

Question 17

Why do the DMF index useful?

Answer 17

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

Question 18

How do we use the DMF Index?

Answer 18

• 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

Question 19

What is the Deans 21 cities study?

Answer 19

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)

Question 20

What are the problems with DMFT?

Answer 20

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

Question 21

What is ICDAS?

Answer 21

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

Question 22

How is ICDAS measured?

Answer 22

Code 0-6

Sound tooth- extensive (more than 1/2 surface)