Epidemiology Of Dental Caries
Dental Caries

Dental caries is an infectious, communicable disease resulting
in destruction of tooth structure by acid-forming bacteria
found in dental plaque, in the presence of sugar
Concepts of caries etiology
Microorganism
Tooth
Substrate
Time
Current concepts of Dental Caries
The development of dental caries is a dynamic process of
demineralization of the dental hard tissues by the products
of bacterial metabolism, alternating with periods of
remineralization
Cyclic Process of Decay
Bacteria plus food
makes the saliva
very acidic within
5 minutes
Demineralization
Remineralization
Saliva is normal
30 minutes
after eating
Demineralization / Remineralization
Demineralization / Remineralization
…….
Etiology of dental caries:
Tooth susceptibility
 Bacterial plaque
 Carbohydrates
 Oral sugar clearance
 Time
 Saliva flow & pH

…….
Epidemiology of dental caries:
Host Factors
Age
 Sex
 Race
 Emotional disturbance

Agent Factors
* Streptococcus mutans…………….initiation of dental
caries
mutans plus sucrose reduces the pH in the plaque to a critical level of
5.0-5.5, which can overcome the buffering capacity of saliva and
result in demineralization of enamel
* Lactobacillus ……………progression of dental caries
Lactobacillus counts are significantly higher in patients with open
caries lesions
Environmental factors
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sunshine
temperature
fluoride
nutrition
social factors
oral environment
Dental caries
Crown caries
Root caries
Occlusal caries
Root caries
Smooth surface
arrested
acute
Continuo…….
Dental caries of primary teeth:
Sequence of caries in primary dentition is as follows:
*mandibular molars followed by maxillary molars, followed by
maxillary anterior teeth.
* Proximal caries progress more rapidly than occlusal caries and
cause higher percentage of pulp exposure.
* Caries in lower incisors is unusual except in rampant caries.
Dental caries of permanent teeth:
1- Mandibular first and second molars.
2- Maxillary first and second molars.
3- Mandibular second premolars, maxillary first and
second premolars, maxillary centrals and laterals.
4- Maxillary canines and mandibular first premolars.
5- Mandibular centrals, lateral incisors and canines.
ASSESSMENT OF DENTAL CARIES
Counts :
Number of persons involved by the disease(presence or
absence).
Proportion :
The prevalence of the disease can express as percentage
Number per 1oo persons
Rates :
Stander unit of population is often used - 1:1000
(10,100,100,10.000……)
Intensity:
Or severity by using an index
What is the index ?
Is a graduated numerical scale with definite upper and lower
limits describing the relative status of a population .
Irreversible………… caries
Reversible……………. gingivitis
MEASUREMENT OF DENTAL CARIES
1- Methods of examination
Type 1…………mirror ,probe,
full mouth x-ray, study model,
illumination ( complete examination)
Type 2…………mirror ,probe, bitewing x-ray, illumination
Type 3…………mirror ,probe, illumination
Type 4…………, tongue depressor , illumination (screening)
Diagnostic criteria
-WHO criteria
- White spots
- Discoloured ,rough areas, softening , undermining
Indices for dental caries
For permanent teeth:
DMF index
D……………. Decayed
M ……………. Missed
F ……………. ...Filled
( DMFT) OR ( DMFS)
For primary teeth:
- def index
- dmf index
- df index
Number of d + m + f surfaces
dmfs Index = ———————————
Total number of primary teeth
Number of d + m + f tooth
dmf Index = ———————————
Total number of primary teeth