Connective tissue repair in circumferential periodontal defects in dogs following use of a biodegradable membrane.

A biodegradable polylactic acid membrane was evaluated for its ability to enhance periodontal regeneration. In 8 Labrador dogs, circumferential defects were created around the maxillary 1st premolars. The defects were combination "1-wall vertical and horizontal". A membrane was adjusted to cover the defect on one side of the jaw, while the contralateral tooth served as control without membrane. After 3 months, healing was evaluated histologically. The results demonstrated that the amount of connective tissue repair with newly formed cementum approximated 50% of the defect height for both test and control groups. Thus, no advantage to the use of membrane was found, which is contradictory to the findings of our previous dog study using the same biodegradable membrane. The possible reasons for this difference in results are discussed relative to suggested mechanisms for membrane effects in periodontal regeneration.