ABSTRACT
Guided bone regeneration (GBR) is a well-established and generally predictable method for repairing alveolar ridge defects and preparing edentulous sites for implant placement. Standard GBR involves filling the space underneath a membrane with autogenous bone or a mixture composed of autogenous bone particles and allogeneic bone tissue or heterologous biomaterials. The use of a barrier membrane for GBR has sometimes been associated with complications, however - reportedly involving exposure, infection, and collapse - and the non-resorbable types of membrane seem to be involved more often than the resorbable solutions. Such complications may be severe enough to defeat the object of the GBR procedure. A non-resorbable high-density polytetrafluoroethylene (d-PTFE) membrane has recently been designed specifically for use in bone-augmentation procedures that seems to assure a good bone regeneration process even when the membrane is exposed to the oral cavity. This case report describes an exposure of a d-PTFE membrane occurring after a maxillary GBR procedure and how it was overcome successfully, enabling implants insertion.
ABSTRACT
The surface characteristics of dental implants play an important role in the osseointegration process. Over the years implant surfaces have been subjected to different treatments, including turning, plasma spraying, coating, sand blasting, acid etching, and anodization. FBR coating is a fully resorbable calcium phosphate (CaP) coating made of brushite, obtained by electrochemical deposition on titanium plasma-sprayed (TPS) implants; this bioactive layer may be totally resorbable in 6-12 weeks and once the FBR coating has been resorbed, the newly formed bone is in contact with the roughness of the TPS surface. Human biopsy of immediately-loaded implants is certainly the most definitive means of determining the occurrence of osseointegration. In this case series the histologic and histomorphometric features of the bone-implant interface are analyzed and discussed in 3 immediately restored implants, retrieved from human subjects at 8, 10 and 12 weeks, respectively. All 3 implants were osseointegrated, with a bone to implant contact (BIC) ranging from 54.4% to 70.1%. The FBR coating was resorbed and replaced by new bone. Osteoconduction was especially noticeable between the implant threads, where the pristine bone was removed during implant bed preparation. The results suggest that the resorption window of 6-12 weeks for the CaP coating seems to be confirmed at least in the human mandible, and that immediately loaded FBR-coated implants placed in the posterior mandible can achieve osseointegration within 6-12 weeks of loading.
