Reduction In Caries Increment Research Articles

Effect of a field program based on systematic plaque control on caries and gingivitis in schoolchildren after 3 years

The effect of a field program, based on systematic plaque control, on caries and gingivitis was tested during a 3-year period on 1,100 schoolchildren. Once every 3rd week the children were given oral hygiene instructions, professional toothcleaning and fluorides topically delivered by specially trained dental nurses. The children of a control group of approximately the same number of pupils, participated in a preventive program consisting of mouthrinsings once every 2nd week with a 0.2% sodium fluoride solution. The children of the third and fourth grades were, at the start of the experiment, selected as reference groups and then continuously examined once every year. At the end of the trial the mean reduction of surfaces haboring plaque and units with gingival inflammation was 59% and 73%, respectively. The reduction in caries increment was 51%.

A Field trial on the Caries preventive effect of a New Dentifrice containing NaF and synthetic zeolite

A new fluoride dentifrice was used on 335 school children for one year and its clinical effect on caries prevention was estimated by means of comparison with the results obtained from a placebo group of 315 children of a neighboring village of similar socioeconomic status and with so close a caries susceptibility at the initial base line examination that the caries extent or prevalence was 1.90 DMFT or 69.9% at the test village, Okura, and 1.98 DMFT or 69.5% at the control village, Sakegawa. NaF and synthetic zeolite were included 0.2% and 45.0% in the test dentifrice but not in the placebo. The fluoride ion activity of test dentifrice decreased somewhat immediately after preparation, but 78% of the initial activity still remained even when it was kept for 60 days at 40°C. The Children brushed their teeth twice a day for one year. The children in the test village showed 38.0% reduction in caries increment on the smooth surfaces and 11.9% reduction in the pits and fissures. These reductions were statistically proved to be significant at the 0.1% and 5% level respectively.

Some statistical aspects of a clinical study on dental caries in children

A significant reduction in caries increment was obtained from dentifrices containing 0.4 per cent stannous fluoride and 0.76 per cent sodium monofluorophosphate, compared to a placebo. The trial was conducted on children aged 12–14 yr over a test period of 2 yr and whole mouth recording was used (150 surfaces/subject). Subsequent analyses showed that partial recording of subjects may be utilized in such trials. Nine methods of partial recording were compared; the most promising involved the examination of 66 surfaces/subject on teeth 4, 5, 6 and 7 in each quadrant and the use of two radiographs/subject compared with four or five required by other methods. The efficiency of stratification and covariance was compared in this trial where some loss of subjects occurred. When the loss of complete replicates exceeded 5 per cent, the single classification analysis of covariance with initial DMFS as a covariate was more efficient than the randomized block analysis of complete replicates where the replicates were formed by stratifying for sex, school, examiner and initial DMFS. No evidence was obtained to suggest that carious lesions develop more slowly or remain stationary longer at a certain stage in the presence of fluorine. The proportion of lesions classified as “smooth decalcified” or “rough decalcified” which reverted to intact was similar in the three treatment groups. The number of errors and wrong diagnoses varied considerably in different parts of the mouth. The error rate, that is the number of errors, reversals, and wrong diagnoses/DMF surface at the final examination, varied from 5 per cent in teeth 4, 5, 6 and 7, to 10 per cent in teeth 1, 2 and 3. The distribution of the residuals of DMFS increment was not normal. However, with the large sample size used in this experiment, the effect of the operation of the Central Limit Theorem was sufficient to make transformation unnecessary.