Epithelial reattachment after gingivectomy in the rat.

It is known that an epithelial reattachment occurs a few days after gingivectomy. Depending upon the surgical procedure and the animal species used, different times have been proposed to obtain a complete reattachment. Nevertheless, it is not known whether there is a correlation between the time required and the sequence of morphologic events involved in this process. To investigate this matter, gingivectomies were performed in the maxillary molars of rats. Specimens were taken 1 to 14 days after the operation and processed for light and electron microscopy. The new junctional epithelium appeared at the 5th day, but the earliest signs of reattachment complex formation were evident at the 8th day. Rudimentary hemidesmosomes and lamina lucida appeared in epithelial cells bordering remnants of fibrin. Anchoring filaments that formed between the earliest hemidesmosomes and the subjacent fibrin crossed the lamina lucida. Simultaneously, segments of lamina densa appeared. At the 11th day insertion of tonofilaments into the attachment plaques and insertion of anchoring filaments in the lamina densa were observed. At the 14th day, full development of the reattachment complex was evident.