Guided tissue regeneration around dental implants in immediate extraction sockets: comparison of resorbable and nonresorbable membranes.

This study was performed to compare the efficacy of guided tissue regeneration (GTR) around dental implants immediately placed into extraction sockets by resorbable of nonresorbable membranes. Mandibular P2, P3, and P4 of four adult beagle dogs were extracted bilaterally, and buccal standard defects were created and measured. Eighteen commercially pure titanium Steri-Oss implant fixtures were placed into the fresh extraction sockets. Four implants were untreated controls, four implants received polytetrafluoroethylene (e-PTFE, Gore-Tex) membranes, five implants received collagen membranes (ParaGuide), and five implants received polyglactin 910 mesh (Vicryl). After 14 weeks, clinical measurements were taken and the dogs were sacrificed and all specimens retrieved for histologic and histomorphometric evaluation. The average gain in bone height was 2.1 mm for untreated control sites, 3.3 mm for Gore-Tex sites, 3.8 mm for collagen sites, and 1.3 mm for polyglactin 910 sites. The greatest gain in bone height and volume was seen for two sites that received Gore-Tex membranes and remained covered for the entire evaluation interval. The results of this study indicate that Gore-Tex and collagen membrane produced good results for GTR around implants immediately placed into extraction sockets. Since collagen membrane does not cause obvious infection and does not need the surgical reentry for membrane removal, it can be a valid alternative to Gore-Tex membrane to improve bone regeneration around dental implants, while polyglactin 910 mesh seems not suitable to be used as GTR membrane in immediate implantation for its high infection rate.