To evaluate through histological and histomorphometric analysis of human biopsies the guided bone regeneration (GBR) potential of allograft, xenograft, and alloplastic materials in combination with resorbable membranes in sockets following extraction.  This randomized controlled clinical trial comprised three experimental groups and one negative control group (n=8). Thirty-two patients were randomized and pos-extraction sockets received either an allograft (human cancellous bone, freeze dried, DIZG, Berlin), xenograft (BioOss; Geistlich Biomaterials, Switzerland), or alloplast (biphasic calcium sulphate, Bondbone, MIS) graft material, while sockets of the negative control group were left empty for spontaneous healing. At re-entry after three months, bone core biopsies of the treated sites were obtained using a 3.2 mm trephine drill. Bone samples were histologically processed for histomorphometric, qualitatively and quantitatively, analyses with respect to percentages of new vital bone, graft particle content, soft tissue, and bone marrow. Statistical analyses were performed through Kruskal-Wallis test, and  p -values were recalculated using Monte Carlo permutation tests ( p <0.05). All three groups presented bone volume suitable for the placement of a dental implant. The xenograft yielded significantly less amount of vital bone in comparison to the allograft and alloplast groups. Comparing the percentage of residual graft particles, there was a significantly greater amount in the xenograft group in contrast to the allograft and alloplast. Similarly, a significant amount of soft tissue (as a function of percentage) was observed within the xenograft group relative to the other groups. No significant differences were detected in the percentage of residual graft particles between the allograft and alloplast groups. Additionally, there was  no significant differences observed in vital bone percentage between the allograft, alloplast and control groups. Regarding the evaluation of bone marrow percentage, the only significant difference detected was between the xenograft and the alloplast material. All studied bone substitute materials exhibited bone apposition and adequate properties for their efficient use in alveolar ridge preservation procedures. Of the three grafting materials, allograft evidenced the greatest GBR potential with the highest percentage of vital bone and the lowest percentage of residual graft particles, while xenografts presented the lowest GBR potential after three months in vivo.

Background : Implant-supported restorations using morse tapper implants have been a reliable restorative option with high success rates.However, longitudinal evaluation of those restoration with Brazilian implant brands must be analyzed. This study was to evaluate the success rate, peri-implantitis and bone loss around morse tapper implants after 8 years under functional loading. Two hundred and two implants were placed in 44 subjects, radiographic evaluation at 2, 12, 36, 60 and 96 months.Aim/Hypothesis : The aim of this longitudinal prospective study was to evaluate the success rate, the incidence of peri-implantitis and peri-implant bone loss means around morse tapper implants with sandblasted and acid-etched surfaces after 8 years under functional loading.Material and Methods : Two hundred and two implants ranging between 3.5-5.5 mm of diameter and 7-13 mm length were placed in 44 subjects with mean age of 50.12 years. Radiographic evaluation was performed by intra-oral radiographies at 2, 12, 36, 60 and 96 months.Demographical data as abutment type, history of periodontitis, smoking and implant loss was also evaluated and associated with clinical parameters.Results : Eight implants were lost during the entire period reaching a success rate of 96.63%. The peri-implant bone loss ranged between 0.86; 0.39 mm at first 2 months to 1.10; 0.77 mm after 96 months, that was statistically significant after 12 months. The incidence of periimplantitis (probing depth higher or equal to 5 mm, bleeding on probing and or suppuration, and bone loss > 3 mm) was of 3.96%. History of periodontitis, smoking and abutments with less than 1.0 mm neck distance were positively correlated with peri-implantitis ( P < 0.01). Conclusion and Clinical Implications: Within the limits of this longitudinal study, it could be concluded that the morse tapper implant system using platform switching present high indexes of success rate, low bone loss and peri-implantitis incidence, at least up to the period of 8 years of evaluation