Guided tissue regeneration: Comparison of bioabsorbable and non-bioabsorbable membranes. Histologic and histometric study in dogs
The purpose of this investigation was to examine the histologic and histometric response of two different bioabsorbable membranes made from a synthetic copolymer of glycoside and lactide. The membranes differed in configuration slightly and were designed to vary in their handling characteristics and resorption rates. The study was also designed to evaluate whether the two membranes were present and intact at one month, and whether the membranes were completely degraded at three and six months. Nine adult foxhound dogs were anesthetized and subjected to flap elevation. Class II buccal furcation defects were created on the second and fourth premolar teeth. The exposed root surfaces were thoroughly denuded of periodontal ligament and cementum, and notches were placed at the newly created bone level. One site received one type of bioabsorbable membrane (Type ~ and the other site received the alternate membrane type I0. The contralateral quadrant received expanded polytetrafluoroethylene (ePTFE) to serve as a control. Flaps were sutured slightly coronal to the membranes, and a broad-spectrum antibiotic was administered for three days. One month following this procedure a second surgical procedure was carried out in order to remove the ePTFE membrane. Three dogs were also sacrificed at this time. Half of the remaining dogs were sacrificed at three months and the remainder at six months. Experimental tissues were fixed and processed for sectioning Descriptive histology and histometric analysis were carried out.
Histologic analysis revealed differences in the degree of inflammation and rate and quality of healing between the bioabsorbable membrane and the ePTFE membrane at one month but not at three and six months. The one-month ePTFE specimen revealed new cementum with inserting collagen fibers and varying amounts of newly formed alveolar bone and no inflammatory cells. The bioabsorbable membranes showed scattered foreign-body giant cells in relation to early resorption of the membranes and connective tissue immaturity. The three- and six-month specimens revealed new cementum with inserting collagen fibers and new bone with both types of membrane treatments. There were, however, small remnants of the bioabsorbable membranes still present. Histometric measurements resulted in no major differences in healing between either of the bioabsorbable membranes or the ePTFE membrane. The authors conclude that similar results can be achieved in guided tissue regeneration procedures with either resorbable or nonresorbable barriers. [M.J.D.]
Caffesse, R.G., C.E. Nasjleti E.C. Morrison, and R. Sanchez, J Periodont, 65:583,1994