Question

I discover a cavity every 2 years. And since I'm terrified of procedures, I don't see my dentist very often, so I cover all cavities every three years.

Question: Now I don't have any cavities. How many cavities will I have in 15 years?

Develop the following.

1. Establish your dynamic hypothesis: BOTG and Causal Diagram.

2. Design the block diagram to run it in VENSIM.

3. Formulate the equations.

4. Run the model in VENSIM and answer the questions based on the simulator. Please take a screen shot of the answer after running the model.

Answer 1

The three main factors in dental caries--diet, microflora and a susceptible tooth--were identified almost 100 years ago. Since that time a large number of further local and general risk factors have been identified. Diet has long been suspected of contributing towards the caries process but positive proof of its role has been difficult to establish. However, the total consumption of sugar, as well as the frequency of its intake, undoubtedly contributes to the onset of dental caries. Diet is a dominant variable in determining dental caries prevalence and it can mask other factors. Differences of opinion exist as to whether specific micro-organisms are the cause of dental caries. There is, however, substantial evidence to support the key role of mutans streptococci in the process. Among local risk factors are the form and arrangement of teeth, salivary flow and oral hygiene. General risk factors include age, sex, race, geographic location and social class. In fact, the whole social-cultural environment of the community in which the individual lives may have an influence on the development of dental caries

The most generally accepted theory as to the cause of dental caries is that certain bacteria in the mouth, in the presence of fermentable sugars, cause the formation of acids which in turn decalcify teeth. Physicians may help reduce the incidence of caries by recommending elimination of refined sugars from the diet, or at least control of the amount consumed.

Cleaning the teeth with a well designed tooth brush after each meal will to a certain extent mechanically remove the fermentable sugar and debris from the teeth. One step further in oral hygiene that may be beneficial is to use a dentifrice with 5 per cent dibasic ammonium phosphate and 3 per cent urea to reduce the formation of acid.

Anything that will increase salivation will aid in buffering any acids that may be present.

A 2 per cent solution of sodium fluoride applied to the thoroughly dried “intact” enamel surface may prevent caries.

Sodium fluoride added to drinking water to a concentration of 1 part per million is utilized by the body in formation of an enamel that is particularly resistant to caries.