Regeneration of Standardized Mandibular Bone Defects Using Expanded Polytetrafluoroethylene Membrane and Various Bone Fillers

The purpose of this study was to evaluate the new bone formation and biodegradability of various bone fillers placed underneath a nonresorbable membrane (expanded polytetrafluoroethylene [e-PTFE]) in standardized defects in a beagle dog model. Mandibular premolars and first molars were extracted bilaterally in six adult female beagle dogs. Three months after the extractions, six rectangular defects (4 mm apicocoronally, 7 mm mesiodistally, and the entire width of the ridge buccolingually) were surgically created in the alveolar processes. All defects were covered with an e-PTFE membrane and stabilized buccally with stainless steel fixation screws. Five different bone fillers were placed under the membranes in a random configuration in each dog: autogenous bone, demineralized freeze-dried bone, anorganic bovine bone, tricalcium phosphate granules, and collagen sponge. One site in each animal was treated with the e-PTFE membrane alone. Following an 8-month healing period, a bone core was harvested from each grafted site using a trephine drill. Samples from each of the grafted sites were evaluated histologically and histometrically for their bone regenerative potential. The result of this study demonstrated a positive effect of bone fillers on bone regeneration when combined with a nonresorbable membrane; however, no significant differences were found between the various bone fillers in terms of their regenerative potential.