One-stage horizontal guided bone regeneration with autologous bone, anorganic bovine bone and collagen membranes - 3-year follow-up from a prospective study

Background Oral prosthetic rehabilitations based on osseointegrated implants have become a valid treatment option to restore edentulous ridges, with several factors involved in implant therapy success. Of these, bone volume at implant insertion is a key factor for predictable long term results. In particular, atrophies within class III present a medium horizontal defect, which complicates the correct placement of regular implants without thread exposure. Aim/Hypothesis To present the medium-term results of one-stage guided bone regeneration (GBR) using autologous bone and anorganic bovine bone, placed in layers, in association with resorbable collagen membranes, for the reconstruction of horizontal bony defects. Material and Methods This study was designed as a prospective clinical study. Partially edentulous patients, having less than 6.0 mm and more than 4.0 mm of residual horizontal bone width were selected and consecutively treated with simultaneously implant installation and bone regeneration by using 2.0 mm of autologous bone and 2.0 mm of anorganic bovine bone that was placed in layers and then covered with a resorbable native collagen membrane. Outcome measures were implant and prosthesis failures, any complications, peri-implant marginal bone level changes, probing pocket depth (PPD) and bleeding on probing (BOP). Results In total, 45 consecutive patients (20 male, 25 female) with a mean age of 52.1 years each received at least one GBR procedure, with contemporary placement of 63 implants. At the 3-year follow-up examination, no patient had dropped out and no deviation from the original protocol had occurred. No implant or prosthesis failed. In six patients (13.3%) the collagen membrane was slightly exposed 1–2 weeks after bone reconstruction. Mean marginal bone loss experienced between initial loading and 30 months afterwards was 0.60 ± 0.20 mm (95% CI 0.54–0.66). The mean BOP values measured at the definitive restoration delivery were 1.23 ± 0.93, while at 3 years they were 1.17 ± 0.78. The difference was not statistically significant (−0.06 ± 0.76+ P = 0.569). The mean PPD values measured at the definitive restoration delivery were 2.62 ± 0.59 mm, while at 3 years they were 2.60 ± 0.54 mm. The difference was not statistically significant (−0.03 ± 0.62+ P = 0.765). Conclusions and Clinical Implications Within the limitations of the present study, the use of a 2.0 mm layer of particulated autologous bone on the implant threads, and a 2.0 mm layer of anorganic bovine to cover the resorbed ridge, in combination with the resorbable collagen membrane, seems to be a viable treatment option for the reconstruction of horizontal bony defects.