The aim of the current study is to evaluate fresh-frozen human bone allografts (FHBAs) used in vertical ridge augmentation clinically and by computed tomography, and to analyze the resulting bone formation and graft resorption. Sixteen FHBAs were grafted in the maxillae and mandibles of 9 patients. The FHBAs, which were provided by the Musculoskeletal Tissue Bank of Marilia Hospital (Unioss), were frozen at -80°C. After 7 months, dental implants were placed and bone parameters were evaluated. Vertical bone formation was measured by computerized tomography before (T0) and at 7 months (T1) after the surgical procedure. Bone graft resorption was measured clinically from a landmark screw head using a periodontal probe. The results were analyzed by Student's t-test. Significant differences existed in the bone formation values at T0 and T1, with an average change of 4.03 ± 1.69 mm. Bone graft resorption values were 1.0 ± 0.82 mm (20%). Implants were placed with varying insertion torque values (35-45 Ncm), and achieved primary stability. This study demonstrates that FHBAs promote satisfactory vertical bone formation with a low resorption rates, good density, and primary implant stability.

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Regeneration of periodontal and alveolar ridge defects utilizing membranes is a well-established procedure in reconstructive surgery. Biomaterial characteristics and membrane design employed in guided tissue regeneration (GTR) techniques play an important role in good results. The purpose of this histologic experimental study in rats was to compare the use of two physical barriers in the osteopromotion by using GTR principles in bone defects created in tibias. Fifteen animals divided into 3 groups were used: group I (non-porous polytetrafluoroethylene (PTFE) barrier), group II (coral hydroxyapatite (HA) blocks), and group III (defects that received no physical barrier). Histological examination showed varied amounts of newly formed bone beneath both types of barriers. The non-porous PTFE barrier showed better results than the HA group. The results of this study suggest that bone regeneration can be successfully enhanced by a submerged membrane technique.

<p><strong>Objective</strong>: The aim of this study was to compare the response of bone tissue in osteotomy under piezosurgery using a CVD tip in rat parietal bone in contrast with the standard protocol using low-speed tungsten burs. <strong>Material and Methods</strong>: A bone defect model was created in parietal bone of 20 male Wistar rats using CVD tip and drill. Five animals were sacrificed after 3, 7, 14 and 28 days and the bone containing the defects was submitted to the histologic and histomorphometric analysis. The results of histomorphometry were statistically analyzed using RM ANOVA with a significance level of α = 0.05. The results were still subjected to Tukey's multiple comparison test. <strong>Results</strong>: The results showed statistically significant difference (p &lt;0.05) between the two types of treatment in the analyzed periods. Piezosurgery promoted slower and more precise cut with less bone loss and less bleeding during surgery, promoting conditions for a faster repair compared to the traditional method of osteotomy, fewer inflammatory cells, faster bone formation, cleaner surgical wound in the experimental group in all periods. <strong>Conclusion</strong>: It was concluded that the use of CVD tip in piezosurgery was proven to be valid for osteotomy, with more precise cuts, less tissue damage, fewer pronounced inflammatory response and faster bone formation in the early periods when compared with low-speed tungsten burs.</p>

<p><strong>Objective:</strong> The aim of this study was to evaluate the effectiveness of platelet rich plasma with and without autogenous bone graft in the bone repair of surgical defects in rabbit tibias. <strong>Materials and Methods:</strong> In this research, 25 adult male rabbits were used. Two defects have been performed in each tibia, divided into four groups: control (C = defect naturally left to heal by clot formation), autogenous (A = bone defect + autogenous graft), PRP (PRP = bone defect + PRP) and autogenous + PRP (PRPA = bone defect + autogenous graft + PRP). All the defects were covered with a dPTFE membrane. Five other animals were sacrificed at 15, 30, and 60-day postoperatively. The pieces containing the defects were processed for histological and histomorphometric analysis. Other five animals were sacrificed after 30 and 60 days and submitted to biomechanical analysis, and all the specimens were sent to the radiographic evaluation of optical density. <strong>Results: </strong>The biomechanical, radiographic, and histomorphometric results showed larger resistance, optical density, and improving bone formation in the groups A and PRPA when compared with the groups C and PRP. <strong>Conclusion: </strong>This study showed there was not an improvement in the radiographic, mechanical, and bone formation parameters when PRP was used individually or associated to the autogenous bone graft.</p>

Objective: This study aimed evaluating histologically and histomorphometrically the response of the conjunctive tissue face to the implant of chlorhexidine chips in the subcutaneous tissues of rats. Study Design: In this research 35 male rats Wistar were used to analyze the biocompatibility and the degradation process of chlorhexidine chip. In each animal, it was made 2 incisions for subcutaneous implantation of chlorhexidine chip (test group) and a polytetrafluorethylene membrane (control group). The morphological changes in subcutaneous implantations were assessed after 1, 3, 5, 7, 10, 14, 21 days. The data were submitted to Friedman nonparametric test to analyze the comparisons among observation periods and to allow the comparison among groups. Results: Differences were found in the analysis of the inflammatory response when comparing the tested materials (p values ≤ 0.05). In test group was observed hemorrhage, edema and intense inflammatory infiltrate predominantly neutrophilic around material. From 3-day and subsequent periods was verified granulation tissue externally at this infiltrate. From 10-day on was observed crescent area of degradation of chlorhexidine chip, associated with neutrophilic and macrophagic infiltrate, that maintained until 21-day. In the control group, moderate inflammatory infiltrate was observed initially, predominantly polymorphonuclear, edema and granulation tissue 3-day period. The inflammatory infiltrate was gradually replaced for granulation tissue, culminating in a fibrous capsule. Giant multinucleate cells situated at contact interface with the coating was examined since 3-day and persisted until 21-day. Conclusion: The chlorhexidine chip induces an intense acute inflammatory response at subcutaneous tissue of rats. Therefore, at conditions of this study was not biocompatible.