Significance of Mechanical Stress on the Development of Periodontal Lesions in Lathyritic Rats

¹ University of Pennsylvania, School of Dental Medicine, Department of Pathology, Philadelphia, Pennsylvania

The relative significance of mechanical stress and the degree of maturity of the connective tissues of the periodontal ligament in the manifestation of the morphologic changes produced by BAPN was studied by the administration of BAPN to suckling, weanling, young adult, and aging rats. The maxillary right molars of all rats, with the exception of the suckling rats, were removed. In all age groups, microscopically recognizable lesions were absent from the periodontal ligament in all cases in xhich mechanical stress was not exerted upon this ligament during the period of administration of BAPN. These observations suggest that in experimental lathtlyrisn mechanical stiress plays an iimiportant role in the manifestation of the morphologic changes of the periodontal ligament and that in lathyritic animals there is no difference in the response to mechanical stress of periodontal connective tissues exhibiting varying degrees of maturity at the beginning of the administration of BAPN.

In the absence of mechanical stress BAPN does not cause microscopic alterations indicative of an interference with the differentiation and morphogenesis of the epithelial and connective-tissue components of the molar tooth buds and with the production of dentin.