A Histopathological Study on the Role of Periodontal Ligaments in Reattachment Process

Abstract

The main purpose of this investigation was to compare the healing process and the type of soft tissue attachment after periodontal surgery in two conditions of root surfaces exposed by bone removal.
In this investigation, four healthy adult monkeys were used. Before surgical phase, healthy periodontium was established by professional cleaning three times a week for a month.
Full thickness gingival flaps were raised and buccal alveolar bone plates were removed by dental chisel within an area extending 2mm mesio-distally, 3mm vertically.
In forty-three exposed root surfaces, residual periodontal fibers and root cementum were preserved, and in forty surfaces, they were removed by root planing.
Two, four, eight and twelve weeks after surgery, the monkeys were killed and examined histometrically.
The results were as follows:
1) In the fiber preserving group, epithelial downgrowth could not be observed 2, 4, 8 or 12 weeks after surgery. But in the fiber removal group, apparent epithelial downgrowth was observed from 4, 8 and 12 weeks, in spite of little gingival inflammation. Twelve weeks after sugery, the difference between them was about 0.5mm on the average.
2) In the fiber preserving group, functionally oriented connective tissue reattachment was observed in proportion of about 70 pecent in the range of measurement from 2 to 12 weeks.
It was considered due to the effect of fiber splicing.
But in the fiber removal group of 2 and 4 weeks materials, much more parallel collagen adhesion to root surfaces was observed. In 8 and 12 weeks after surgery, functionally oriented fibrous attachment increased as a formation of new cementum.
3) The results of statistical analyses revealed that the amount of functionally oriented connective tissue reattachment is correlated to residual periodontal fiber 2 and 4 weeks after surgery, but 8 and 12 weeks, correlated to the amount of new cementum formation.
4) A side-result obtained from this investigation was the tendency that epithelial downgrowth occured along smooth root surfaces, rarely on rough root surfaces.