Biomedical subjects
Publications and source records attributed to I Gedalia.
Daily topical application of 2% NaF on hamster molars for 4 days in vivo, followed by acidulation (grapefruit beverage, pH 3.3) resulted in a lower caries rate than NaF followed by water application. Fluoride uptake was somewhat higher, but not significantly so in the acidulated group.
The effectiveness of topical 2% sodium fluoride applied with and without 10% strontium chloride pretreatment was compared in patients complaining of tooth hypersensitivity. In addition the radiopacity of 2% sodium fluoride and 25% strontium chloride treated dentin was studied in vitro. Reduction of sensitivity to cold and mechanical stimuli was evaluated during a period of 3 months by pain scoring in the exposed cervical dentin of homologous teeth on the two sides of the jaws. There was a significant decrease in the sensitivity of the exposed cervical dentin after treatment with sodium fluoride solution with or without pretreatment with strontium chloride solution. At the end of the experimental period the combined strontium and fluoride treatment was found to be more effective than that of fluoride alone in reducing sensitivity to cold. The increase in radiodensity of dentin samples immersed in strontium chloride was statistically significant, while there was no significant increase in density for the samples immersed in sodium fluoride solutions. A mineralization process is possibly the effective means by which fluoride or strontium diminishes sensitivity of dentin.
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The effect of local application of low fluoride concentrations on the healing of experimental bone-radii fractures in 20 rabbits was examined. No external fixation was required after the osteotomy and gelfoam being used as a medium for fluoride application. Histologic mineral and mechanical strength measurements were carried out on the healing callus. There were no significant changes in the ashpercentage and the fluoride concentration of the ash between the experimental and control callus. A significantly higher percentage of ossified tissue was found in the fluoride treated callus. The breaking strength was found to be significantly higher in the bone fractures treated with fluoride, whereas there was no notable difference between the surface areas. It is postulated that the greater amount of ossified tissues, the differences in organization of the bone trabecules, and/or an improved mineral crystallinity may be responsible for this result.
A single application of fluoride to the epiphysis of the femur induced accelerated bone formation. The additional bone gave rise to a stability effect on the implant inserted in the femur as expressed by an increased dislodgement force required.
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The effect of the local application of fluoride on the healing process of experimental calvarial defects in rats was studied. A total of 172 male rats, 6 weeks old, weighing 100 to to 160 gm, were used in the experiments. Two standard defects, each approximately 2.8 mm in diameter, were drilled through the parietal bones on either side of the sagittal suture. In one half of the rats that were operated on, a 20-minute topical application of 2% acidulated (0.1 M H3PO4) NaF solution was used. The control rats underwent the same local treatment with saline solution. Groups of 9 to 13 rats were killed at 4, 5, 7, 9, and 12 weeks after the operation. Radiographs of each calvarium demonstrated the healing area in the bone. Linear bone apposition was measured from histological sections. Fluoride content was determined in ashed calvaria with an Orion electrode. The results indicate that all fluoride-treated groups had increased bone gain compared with the control group. The histological examination revealed no major differences in the structure, number, and size of the cells of the newly formed bone in either group. The mean fluoride concecreased until completion of the experiment.
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Accumulation of dental plaque for 3 and 7 days respectively was determined by calculating the difference between the postcollection and precollection weights of enamel slabs attached to orthodontic bands cemented to the upper first molars of 3 subjects. Pretreatment of the enamel slabs with amine-fluoride or -chloride respectively-at an equivalent amine concentration-prevented plaque deposition on the slabs, whereas pretreatment with sodium monofluorophosphate was less effective. The fluoride concentrations of all fluoride-pretreated enamel slabs were similar. No convincing demonstration of significant differences between the treatments could be predicted in view of the discrepancy in results at the 3- and 7-day test periods.
The effect of combined administration of chlorhexidine and fluoride in the drinking water of hamsters on plaque and caries prevention was studied. Plaque indices of the hamsters receiving chlorhexidine either alone or simultaneously with fluoride were significantly lower than those of the control and fluoride only treated hamsters. The type of plaque indices used in this investigation was area scores. The necessity of quantitatively assessing plaque by several parameters was emphasized. The degrees of caries of the experimental groups were significantly lower than of the control group during the cariogenic diet regime. The anticariogenic effect of chlorhexidine and fluoride at low concentrations each provided simultaneously with a cariogenic diet, was confirmed. The differences in caries rate between the experimental groups were not significant. No additive effect on the cariostatic action of chlorhexidine and fluoride was observed when both reagents were applied simultaneously due probably to the low F concentration in the drinking water. The results did not show a direct quantitative relationship between plaque and caries.
The effect of the osteogenic capacity of fluoride on autogenous iliac cancellous bone and marrow transplants was studied in experimentally created periodontal defects. Eight dogs, 2 years old, weighing between 10 to 15 kg each, were used. The right side of the upper jaw served for creation of the experimental (fluoride-treated) pockets and the left side for the control (saline-treated) pockets. Fluoride treatment was carried out by a single topical application of a high concentration of fluoride in the periodontal defects and by application of a low concentration of fluoride to the bone marrow transplants. Intraoral periapical radiographs were taken immediately after implantation, and at time of sacrifice. Changes during bone healing were assessed histologically and by radioopacity measurements. The newly formed bone in the control and fluoride-treated areas did not differ in quality. Radioopacity in the experimental defects was significantly higher in comparison with that found in the control areas. The increase was probably due to greater bone formation in the fluoride-treated defects. The difference decreased with the duration of the healing intervals. Cementum was deposited in both control and experimental sites.
1. Daily rinsing with water does not prevent plaque accumulation and leads to increased levels of gingival inflammation. 2. Toothbrushing or mouth rinsing with sodium fluoride alone decreases plaque accumulation and improves gingival health. 3. The combined method (toothbrushing and rinsing with sodium fluoride) is the most effective. Confirmation of the above results and conclusions requires additional experiments carried out over a longer period of time.
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