1. Dr Hidayathulla Shaikh
Diet and Dental Caries
Dr Hidayathulla Shaikh

2. Objectives At the end of the lecture students should be able to –
To know what is diet and nutrition
To discuss Epidemiological evidence in diet and dental caries
To explain Experimental evidence in diet and dental caries
To discuss Stephens curve.

3. Introduction
Food is an essential and continuing component in the complex process of maintaining good health through out life.
For proper function even if there is no stresses are present , every cell of each organ tissue system and structure has a continuing demand for nutrients.
To perform its specialized dynamic and inter related functions.

4. Diet – is defined as the types and amount of food eaten daily by an individual.
Nutrition – is defined as the science of food and its relationship to health.
It deals with the part played by nutrients in the body growth, development and maintenance.

5. Evidence linking Diet and Dental Caries
The evidence linking diet and dental caries can be summarized under the following headings
1) Historical evidence
2) Epidemiological evidence
3) Experimental evidence

6. 1) Historical evidence
Oral disease has been a problem for humans since the beginning of time. Skulls of the Cro-Magnon people, who inhabited the earth 25,000 years ago, show evidence of tooth decay.
There is an evidence of tooth decay found in 7 out of 32 skulls, in Neolithic man dating from the bronze age.
But the skulls of Eskimos were free from caries.

7. 2) Epidemiological Evidence
A) Tristan da Cunha study
Tristan da Cunha is a remote rocky island in south Atlantic region.
Before 1930 and 1940 onwards studies showed no evidence of dental caries in this region because of consumption of raw diet.
But after volcanic eruption in 1964, people living in this area moved to other areas which led to change in their dietary habits.
The study conducted after 1964 showed they developed dental caries.

8. B) Evidence from World War II
Due to sugar restriction for civilians in world war II, dental caries reduce among civilians.
At the same time dental caries among army personnel was increased due to increase in sugar consumption.
More quantity of ready made food items were supplied to the army personnel during war times.

9. C) Hereditary Fructose Intolerance (HFI)
Hereditary Fructose Intolerance is a disorder of fructose metabolism.
Patients having intolerance to fructose avoid fructose and fructose containing dietary products.
Because consumption of fructose causes nausea, vomiting, sweating, cramps, coma and even death.
Hence studies have found that dental caries in these patients is very low.

10. 3) Experimental Evidence
A) Animal studies –
Orlando et al, did study on rats and found…
Germ free rats fed on carbohydrates produced no caries.
When the rats were fed through stomach tube in the presence of cariogenic bacteria in the oral cavity, no caries were found.
Others studies have shown sugar in solution causes less caries than solid sugars.

11. B) Human Studies B1) Vipeholm study ( Gustaffson et al 1954)
This study was conducted in an adult mental institution in Sweden.
Before starting the study they were under normal diet, later were divided into different groups depending upon the type of food they consumed.
The groups were (1. Control group, 2. Sucrose solution group, 3. Bread group, 4. Chocolate group, 5. Caramel group, 6. An 8 toffee group, 7. A 24 toffee group).
The study investigated the effects of consuming sugary foods of varying stickiness (different oral retention times) and at different times through out the day on the development of caries

12. conclusions of the Vipeholm study
Increase in carbohydrate increases the caries activity.
The risk of caries is greater if the sugar is consumed in the form that will be retained on the surfaces of the teeth.
Consumption of sugar in-between meals was associated with a marked increase in dental caries.
The increase in dental caries activity disappears on withdrawal of sugar-rich foods.

13. B2) Hopewood House Study (Harris and Sullivan, 1942-67)
Study was conducted in New South Wales, Hopewood House institution, in Australia.
Hopewood institution is an orphan house containing children from birth to 12 years of age.
These subjects were on diet rich in milk products and vegetables. The drinking water was having low amount of fluoride.
Their oral hygiene practices were poor. Their diet mainly consisted of whole wheat, soya beans, and nuts.
Cheese, sugar and refined carbohydrates were totally excluded. Observation was followed up to 13 years of age.

14. Findings of the study
Significant caries reduction in spite of poor oral hygiene and low level of fluoride in drinking water.
When the children go out of this institution after study period was over at the end of 13 years and at later stage when they were exposed to diet like any other child, containing all sugars.
The caries rate started increasing and the caries experience of children of Hopewood study was almost similar to state school children.

15. The conclusion of Hopewood house study was……
Though the children were on lacto-vegetarian diet right from the birth, they did not have any special protection against dental caries when teeth were exposed to sugar.

16. B3) Turku Sugar Study ( Scheinin & Makinen 1972-74)
The study was carried out in Turku, Finland, to compare the carcinogenicity of Sucrose, Fructose and Xylitol.
Xylitol is a sweet substance not metabolized by plaque micro organisms.
In a 2 year study 125 young adults were divided into 3 groups based own their own preferences.
They consumed the entire dietary intake using these sugars extensively (Sucrose group – 35 people, Fructose group – 38 people, and Xylitol group – 52 people).

17. Findings of the study
After one year
Sucrose and Fructose had equal carcinogenicity whereas Xylitol produced almost no caries.
After second year
Caries had continued to increase in the Sucrose group but remained unchanged in Fructose group where as Xylitol produced almost no caries.
Therefore -
Fructose was less cariogenic than Sucrose
Xylitol was non cariogenic or even anti cariogenic (because of the number of reversal of early white spots lesions)

18. Stephen curve
Stephen using microelectrodes, recorded the pH values of dental plaque before, during and after glucose rinse.
A typical response was observed, and these curves are referred to as Stephens curves.
It has 3 main characteristics,
A) Under normal conditions PH of plaque is constant,
B) Following exposure to sugars pH drops very rapidly in few minutes to its lowest level ( critical pH) and at this pH tooth surface is at risk
C) Slowly after sometime (30-60 minutes) pH returns to its original values.

19. During critical pH the tooth minerals dissolve to buffer the acids, repeated fall of pH over a period of time leads to more and more mineral loss from the tooth.
The salivary buffers are also ineffective once the pH drops to 5 and below.
This process initiates the process of dental caries, if the pH drops to 3 or 4 over a period of time the surface layer of tooth is irreversibly lost.
Frequent ingestion of sucrose has lot of influence in initiation and development of caries in newly erupted teeth compared to mature old teeth.

20. Classification of sweeteners
A) Non caloric sweeteners
They don’t provide energy but provide intense sweet taste, they are not metabolized by acids.
Ex – saccharine, aspartame, cyclamate
B) Caloric sweeteners
They provide energy and are used in medicines, food products, sugar free chewing gums, toothpaste etc
They are of 2 types
Sugars – like fructose, glucose, lactose and sucrose.
Sugar alcohols – like sorbitol, lycasin, Xylitol, coupling sugar.