brief description of prevalence of dental decay

1. EPIDEMIOLOGY OF
DENTAL CARIES
RAJAN CHAUDHARY,
BDS 3RD YEAR, 5TH BATCH ,

2. INTRODUCTION
 The word “caries” is derived from Latin word meaning “rot” or decay.
 In 1890, Miller gave the chemoparasitic theory for dental caries.
 Dental research since that day has provided so many factors which seemed to influence the occurrence
of caries. So, instead of finding ‘a cause’ of dental caries, the concept of ‘multifactorial disease’ become
more acceptable.

3. EPIDEMIOLOGY
 “Epidemiology can be defined as the study of the distribution and determinants of health related states
or events in specified population and the application of this study to control the health problems .”
John Last 1988.
DENTAL CARIES
 “Dental caries is defined as a irreversible, microbial disease of the calcified tissues of the teeth,
characterized by demineralization of the inorganic portion and destruction of the organic substance of
the tooth, which often leads to cavitations .” SHAFER, HINE ,LEVY

4. GLOBAL SCENARIO
 Dental caries is still a major health problem in most industrialized countries, affecting 60-90% of school
children & vast majority of adults. . It is the most prevalent oral disease in several Asian and Latin
American countries, while it appears to be less common and less severe in most African countries.
 The WHO records a Global DMFT of 1.61 for 12 year old in 2004, a reduction of 0.13 as compared to a
DMFT of 1.74 in the year 2001.
 Various studies conducted in different countries at different time periods have given evidence that a
substantial decrease in caries prevalence in the last decade has been found among western countries
whereas in case of developing and underdeveloped countries, prevalence of caries seems to be
increasing.

5. WHO REGIONS DMFT
AFRO/ African region 1.15
AMRO/ American region 2.79
EMRO/ eastern Mediterranean region 1.58
EURO/ European region 2.57
SEARO/ south east Asian region 1.12
WPRO/ western pacific region 1.48
GLOBAL AVERAGE (among 188 countries ) 1.61

6. NEPALESE SCENARIO
 According to the Nepal National Pathfinder survey 2004, 58% of 5-6 yrs old children suffer from Dental
Caries and 45% of 9-11 yrs old children suffer from tooth pain.
 It was found that the prevalence of dental decay is low in adolescents who are studying in school (i.e.
25.6% for 12- 16 yrs old). The probable reason for this is use of fluoridated toothpaste, Whereas, 64%
of other adults suffer from tooth decay.
 Lastly , it was reported that 93% of children had decayed component found in most of the tooth.
 According to the Annual Report (2009/10), 3,92,831NEPALESE had Dental caries
 In the total OPD visit, 3.08% is related to oral health in which problem regarding Dental caries is
maximum.
 It shows that Nepal has a high incidence of problems in the area of dental health. There are different
divisions working under the Department of Health Services, but not the Oral Health Division. The
second long term health plan (1999-2017) has put oral health into essential health care services and oral
health for the first time into a primary health care approach.

7. DENTAL CARIES REPORT
Annual report on Number of persons
2009/2010 3,92,831
2010/2011 4,02,142
2011/2012 4,21,033
2012/2013 4,33,282
2014/2015 4,44,088

8. Miller's chemico-parasitic theory(the
acidogenic theory):-
Proposed by Willoughby D Miller, 1890
 This theory is a blend of both chemical and parasitic theory proposed earlier. According to this theory,
dental caries is a chemico-parasitic process consisting of 2 stages: first, decalcification of enamel and dentin
(preliminary stage) second, dissolution of the softened residue (later stage) and the acid causing primary
decalcification is produced by the fermentation of starches and sugar from the retained corners of teeth.
 Hence Miller advocated an essential role of 3 factors in the caries process: the oral microorganisms, the
carbohydrate substrate, and the acid. Even though, at that time, this theory couldn’t explain
1) predilection of specific sites on a tooth
2) initiation of smooth surface caries
3) why some populations are caries free
4) the phenomenon of arrested caries.
This theory is still considered as the backbone of current knowledge and understanding of the etiology of
dental caries.

9. EPIDEMIOLOGICAL FACTORS FOR
DENTAL CARIES
 Dental caries is a multifactorial disease in which there is an interaction between three principle factors:-
 AGENT /micro-organism/ cariogenic biofilm
 HOST/ tooth surface
 SUBSTRATE
 In addition, a fourth factor “TIME”, is also considered. This concept is shown in the “Keyes diagram”. All
the factors must be present and must interact with each other for dental caries to develop.

11. Agents/ micro-organism
 A substance living or non living or a force tangible or intangible, the excessive presence or lack of which
may initiate disease process.
 Mutans Streptococcus – initiation of smooth surface caries
 Lactobacillus - Initiation of pit and fissure caries, progression of smooth surface caries
 Actinomyces - Root caries
Role of dental plaque:-
 Dental plaque is a complex, metabolically interconnected, highly organized, bacterial ecosystem.
 It is a structure of vital significance of the carious lesion. An important component of dental plaque is
acquired pellicle, which forms just prior to or with bacterial colonization and may facilitate plaque
formation.

12. A susceptible host tissue
 Something that affords subsistence or lodgment to an infectious agent under natural condition.
 In case of dental caries, host is the tooth itself
PREDISPOSING FACTORS:-
1. Presence of deep, narrow, occlusal fissures or buccal and lingual pits.
2. Alteration of tooth structure by disturbance in formation or in calcification.
3. Teeth which are mal-aligned, rotated or out of position may be difficult to clean and tends to favor
the accumulation of food and debris .
Healey and Cheyne (1943) studying caries activity in the University of Minnesota students reported that
44.4% and 47.5% of the maxillary teeth were involved in men and women respectively, compared to
33.1% and 34.4% of the mandibular teeth in respective gender. It may relate to gravity and the fact that
saliva, with it’s buffering action would tend to drain from the upper teeth and collect around the lower
teeth

13. CARIES SUSCEPTIBILITY OF
INDIVIDUAL TOOTH SURFACE
OCCLUSAL
MESIAL
BUCCAL
LINGUAL
OTHER HOST FACTORS
1) Saliva
 Composition
 pH
 Quantity
 Viscosity
 Antibacterial factors.
2) Race and ethnic groups
3) Age
4) Gender
5) Hereditary
6) Emotional disturbances.
7) Nutrition
8) Socio-economic Status

14. A suitable local substrate
 The role of diet and nutritional factors deserves special consideration. The physical properties of food
may be significant by affecting food retention, food clearance, solubility and oral hygiene.
 Various factors that considered among the properties of diet:-
1. Physical nature of the diet
2. Carbohydrate content of diet
3. Vitamin content of diet
4. Calcium and phosphorous dietary intake
5. Fluoride content of diet.

15.  An increase in carbohydrate mainly sugar/sucrose/ disaccharide definitely increase caries activity.
 Risk of caries is greater if the sugar is sticky in nature.
 The caries activity is greatest, if the sugar is consumed between meals
 Increase in caries activity varies widely between individuals
 Upon withdrawal of the sugar rich foods, increase activity rapidly decrease and disappears
 A high concentration of sugar in solution and its prolonged retention on tooth surfaces leads to increase caries
activity.
 The physical from of carbohydrate is much more important in
Cariogenicity than the total amount of sugar ingested

16. ENVIRONMENTAL FACTORS
 GEOGRAPHIC VARIATIONS
Following geographic factors influence the parameters
i. Sunshine
ii. Temperature
iii. Rainfall
iv. Fluoride level
v. Total water hardness
vi. Trace elements
vii. Soil
viii. Relative humidity

17.  Sunshine
The high correlation leads to consideration of the mechanism relating sunshine to caries. Ultraviolet light
from the sun is known for its ability to promote synthesis of vitamin D in skin tissue and thus reduce caries
incidence.
 Temperature
Temperature varies with latitude and altitude. It acts to vary the caloric requirements and water intake of
humans.
One study by US department of agriculture showed that the consumption of baked foods and sugar to be
higher in the north where temperatures are low. Hence lower the temperature, higher the caries
prevalence.
 Relative Humidity
Humidity shows higher correlation with caries prevalence. Higher the humidity, more moisture in the
atmosphere which block the UV rays and sunlight .Hence increased caries activity.

18.  Rainfall
Rainfall which leaches minerals from the soil and blocks sunlight. Though no latitude relation is evident,
there is evident, there is regular decrease in rainfalls as one proceeds inshore. The mechanisms by which
relative humidity and rainfall might be linked to dental caries, either together or separately.
 Fluoride
Fluoride is most common in deep-well waters, and deep wells are most common in inshore areas.
 Water Hardness
Water hardness is measured by the concentration of calcium carbonate. An inverse relation is seen
between caries and water hardness.
 Trace elements
Selenium is the first micronutrient element shown to be capable of increasing caries, particularly when
consumed during the developmental period of the teeth and incorporated into their structure

19.  Soil
Food stuffs grown in Soil with higher PH , with molybdenum, lowers the caries incidence.
 Social Factor
Social factors like economic status, social pressure, provision of good preventive measures etc. might
create more demand for better dental care and leads to lesser caries prevalence.
 Industrial hazards
Carbohydrate dust and acid fumes are both known to be deleterious to the teeth, the one promoting
caries and other chemical erosion.

20. THANK
YOU