Loss of connective tissue attachment in the marginal periodontium of the mouse following blockage of eruption.

Abstract

In an attempt to investigate which factors are involved in modulating the degradation of periodontal ligament carried into the supra‐alveolar region during the eruption of continuously growing teeth, the lower right incisor of the mouse was restrained from erupting by pinning it to its alveolar process. Animals were killed at time intervals varying from one hour up to nine months after pinning and their lower jaws processed for microscopic examination and histometric measurements.It was observed that, following blockage of eruption, progressive loss of connective tissue attachment occurred in the marginal periodontium throughout the entire experimental period. Loss of attachment and concomitant apical migration of the junctional epithelium apparently were neither related to eruption nor to plaque‐related inflammatory changes. These regressive features were not seen, atleast not to the same extent, in a comparable experiment involving molar teeth which are not subject to a rapid continuous eruption. Although in the latter teeth some lime‐related loss of connective tissue attachment was noted, its overall rate was, on the average, less than one fifth of that calculated for the pinned incisors.It is concluded that changes of the attachment level in the marginal periodontium of the incisor are caused by local intrinsic factors possibly connected with epithelium‐connective tissue interactions near the apical termination of the junctional epithelium.