Effects of fluoride on dental pulp of young rabbits

Fluoride has been adopting as an anticariogenic agent for many years. Many histologic experiments with the effect of fluoride were made on dental hard tissue, but little is known about its effect on dental pulp. We made histopathological tests on dental pulp of rabbits during administration of fluoride. In this study, 24 young New Zealand rabbits aged 7 days were used. The experimental group (N = 20) was given two intraperitoneal injections of sodium fluoride that contained approximately 7 mg F/kg body mass. The control group (N = 4) was injected with an equivalent volume of normal saline. At the thirteenth day after the final injection, the mandibles were collected and processed according to routine histologic methods. Selected sections were stained with hematoxylin and eosin stain. The mandibular incisor pulp was microscopically examined. The following results were obtained. In the experimental group, histopathologic alterations were observed in the pulp, with loss of palisading of the odontoblastic layer. Slightly elongated swollen odontoblasts were found which showed hydropic alterations. Dilatation and hyperemia of blood vessels were also noted. This dose affected deciduous root resorption and changes in secretory ameloblasts; and also appeared to disturb the dental pulp. The present observations of initial reactions in the pulp following intraperitoneal injection of fluoride are considered suitable as a basis for detailed discussion of histopathologic implications.