Dental caries in rats

I was pleased to see the article by Almeida et al in the July 2004 edition of Homeopathy[ ¹ ]. However, on reading the article I was not surprised that they failed to produce caries in the rats even in the control groups. Unfortunately this failure, in my opinion, rendered the whole article meaningless.

I am not familiar with the methods of production of caries in rats but in humans it is directly related to the frequency of ingestion of sucrose. Quantity is not relevant. One sugar in your tea or five sugars is the same. Most of it is swallowed. It is the number of cups a day that counts. At the surface of dental enamel calcium ions are constantly being removed and replaced. Acid production, from bacteria that ingest sucrose, removes calcium. After the intake of sucrose, acid levels in the saliva begin to rise within 1 min and are back to normal after 30 min. It takes 6 h for the calcium to be replaced by passive diffusion from the saliva. If more sucrose is ingested within this 6 h period the cycle will be broken ie, calcium loss continues. If this increased frequency of sucrose ingestion continues, caries will develop. In this experiment the sugar diet was offered twice a day allowing sufficient time for the lost calcium to be replaced. It is not surprising that caries did not develop.

Fluoride does not prevent tooth decay but it does reduce it by 50%. To use fluoridated water in a study trying to create tooth decay is not to be advised. It would not be difficult or costly to use a non-fluoridated water. To use fluoridated water when one of the control groups is administered NaF 0.05% also weakens the scientific validity of the experiment.

They suggest that placing cotton swabs daily (I assume that means once a day) prevented the caries production. In humans there is no relationship between cleaning one's teeth and tooth decay. I cannot see why this should not also apply to rats. Humans have great difficulty removing all the plaque(bacteria) in their mouths with a tooth brush and floss. One placement of a cotton swab in a rat's mouth will not remove sufficient bacteria to prevent decay. In humans plaque forms again on the tooth surface within 2 h of its removal, without eating. If humans with decay are eating sucrose more than four times a day, the acid attacks will remove calcium resulting in decay. Brushing once or twice a day will not replace that calcium or stop its removal.

Correct brushing and flossing is effective in preventing gum disease. Plaque build up that causes gum disease works on a 48 h cycle. Brushing once or twice a day breaks that cycle.

The fact that the homeopathic remedies Calc-p, Nat-f, Calc-f produced deposits and/or precipitates is of interest to homeopathic dentists. Not to have analyzed these deposits for ‘technical reasons’ is disappointing.

In summary the above article failed because

• 1. The daily frequency of the cariogenic diet was too low. Small servings, 8–10/day would be more effective in producing tooth decay.

• 2. Thirty-five days is insufficient time to produce decay. I would suggest 100–150 days. If a shorter time is required then a higher frequency of the cariogenic diet is required.

• 3. The use of fluoridated water was a mistake.

• 4. Their assumption that the daily use of cotton swabs soaked in water is flawed.

• 5. They did not identify the composition of the deposit/precipitate.

It appears that the authors are not dentally qualified. I would suggest that they employ a dental advisor to check their caries producing protocol. I would also suggest that they trial their caries producing protocol before repeating the full trial to establish that they can produce caries.

I hope the above comments are of some use for this paper and other possible future papers that may cover this subject.

• Reference

• 1 Almeida N.T., D’Almeida V., Pustiglione M. The effect of fluorine and homeopathic medicines in rats fed cariogenic diet. Homp 2004; 93: 138-143.