Enhancement of Osseointegration of Implants Placed into Extraction Sockets of Healthy and Periodontally Diseased Teeth by Using Graft Material, an ePTFE Membrane, or a Combination

Background: Advanced periodontal disease as well as failed endodontic teeth are the most common reasons for tooth removal and simultaneous implant placement. Purpose: To determine whether the addition of a bone substitute graft material and/or a guided bone regeneration membrane added to the site of an immediately placed implant would increase the development of lamellated bone, particularly in the presence of bone defects. Materials and Methods: Four treatment modalities associated with the immediate placement of hydroxyapatite-coated endosteal screw implants into extraction sockets of healthy (C/H) and periodontally diseased teeth (T/PD) were tested. Five dogs with healthy teeth and five dogs with naturally occurring periodontitis were chosen for the study. Each dog received eight implants after extraction of four mandibular and four maxillary premolars. Four implants were submerged for 3 months and four for 6 months. The implants were either inserted alone (subgroup A); surrounded by a GORETEX® membrane (subgroup B; W.L. Gore & Associates Inc., Flagstaff, AZ, USA); surrounded by PepGen P-15® (Dentsply Friadent CeraMed Dental Co. Denver, CO, USA) at coronal area (subgroup C); or surrounded by a combination of graft material and the ePTFE membrane (subgroup D). Implants in group A were osseointegrated in both C/H and T/PD groups with similar bone-implant contact ratios (BICRs). Results: ePTFE membrane significantly improved the BICR of the 6-months implants, whereas graft material significantly increased the BICR at 3 months and maintained the gain thereafter. The graft material and membrane combination further improved the BICR and significantly increased lamellated bone in crestal bone of all implants. Conclusions: This study provides experimental evidence in support of use of graft material with immediately placed implants, particularly in presence of bone defects that initially reduce the BICR such as in periodontitis. Adding an ePTFE membrane to graft material resulted in a greater replacement of woven bone by lamellated bone. Clinical trials in humans are recommended as a follow-up of this experimental study.