Localized bone augmentation with cortical bone blocks tented over different particulate bone substitutes: a retrospective study.

PURPOSE: To assess the efficacy of a block tenting technique for reconstruction of vertical or horizontal alveolar ridge defects. MATERIALS AND METHODS: Patients who underwent a block tenting graft technique between 2005 and 2010 were analyzed retrospectively. Intraoral bone blocks (ramus, chin, or tuberosity) or allogeneic blocks were fixed at 4 mm from the deficient area, and the gap was filled with bone substitutes, with or without plasma rich in growth factors (PRGF). Implants were placed simultaneously or 4 to 5 months postgrafting. Patient demographic information, amount of width/height augmentation after 4 to 5 months of healing, complications, and contributing factors were gathered and analyzed. RESULTS: One hundred two patients were enrolled. Among the horizontal augmentations, the greatest width increase was achieved in the anterior maxilla (4.31±0.93 mm). The average height increase in the vertically augmented regions was greatest in the posterior maxilla (5.75±2.22 mm). Mean horizontal augmentation was the greatest with ramus (3.65±0.65 mm) and allogeneic materials (3.97±0.79 mm). The greatest vertical gain was achieved with tuberosity blocks (4.25±3.06 mm) and a combination of allogeneic/autogenous bone particles (3.90±1.05 mm). Application of PRGF showed no appreciable effect. The most common primary complications of surgery were hematoma and inflammation. The most common complication in the anterior maxilla was hematoma. Inflammation was the most common complication associated with ramus grafts, while hematoma occurred most often in cases with chin and tuberosity grafts. Total graft failure occurred in 13 patients, mainly associated with the allogeneic blocks. Most patients were followed for 11 to 38 months. Five of 237 inserted implants failed to osseointegrate. CONCLUSION: The block tenting technique might be effective for localized ridge augmentation and may reduce the amount of autograft required from donor sites.

Sinus augmentation using human mesenchymal stem cells loaded into a beta-tricalcium phosphate/hydroxyapatite scaffold.

OBJECTIVE: Implant placement in the posterior maxilla may often be contraindicated because of insufficient bone volume and presence of the maxillary sinus. In these situations, sinus floor augmentation frequently has been proposed as the best treatment. This clinical study was based on the hypothesis that the clinical effectiveness of adult mesenchymal stem cells (MSCs) loaded to the biphasic scaffold. METHODS: In this report, the clinical and radiographic results are presented on 6 consecutively treated patients using MSCs in combination with biphasic hydroxyl apatite/ beta-tricalcium phosphate (HA/TCP) for sinus elevation. All the patients in the study had less than 3 mm initial bone height in the posterior maxillary area (IBH). MSCs were cultured and expanded from bone marrow aspirate for each patient. Three months after sinus elevation, radiographic evaluation was performed for the patients and the secondary bone height was measured (SBH(1)). In the second stage surgery, 30 implants were placed. Trephine bur was used as a pilot drill and a core biopsy was obtained from each implant site. Prosthetic rehabilitation of the patients was performed after 4 months. Secondary bone height was measured 9 months after implant placement (SBH(2)). RESULTS: Of 30 implants, 28 (93%) were considered clinically successful. Two implants were removed due to mobility at the time of surgical exposure. Histologic evaluation of the biopsy specimens revealed numerous areas of osteoid and bone formation HA/TCP, with no evidence of inflammatory cell infiltrate. Mean bone regenerate was 41.34%. Clinically, no complications were observed, and all implants were considered clinically osseointegrated after 4 months. Mean bone height was measured 3 and 12 months after sinus grafting (mean of SBH(1)= 12.08 mm and mean of SBH(2)= 10.08 mm). CONCLUSIONS: These clinical and histological findings suggest that sinus grafting with HA/TCP in combination with MSCs provide a viable therapeutic alternative for implant placement. The findings suggest that the addition of MSCs to bone derivative/substitute materials may enhance bone formation in the maxillary sinus area. Of course more studies with the control groups are needed for the evaluation of this method as a clinical solution for the patients.

The effect of a constant electrical field on osseointegration after immediate implantation in dog mandibles: a preliminary study.

PURPOSE: The long time span between insertion of implants and functional rehabilitation often inconveniences patients. Accelerating bone growth around dental implants can shorten this time span. This in vivo study evaluated the effect of a constant electrical field on bone growth around dental implants. MATERIALS AND METHODS: Four mongrel dogs were used in this study. Sixteen dental implants were placed immediately after extraction of the first premolar and molar teeth. A constant electrical field (CEF) generator was placed in the mucoperiostal pouch created from the subperiostral dissection under the inferior border of the dog's mandible and connected to the experiment side fixtures. CEF provided 3 V of electrical potential during osseointegration. Histologic sections were stained with hematoxylin-eosin and observed under light microscopy. The sections were analyzed histomorphometrically to calculate the amount of newly formed bone. Statistical analysis was performed with SPSS 11.0 computer software (alpha= 0.05). RESULTS: At the end of the first stage of the osseointegration (90 days) CEF group sections showed enhanced growth of the trabeculae compared with the control group. Statistical analysis revealed significant differences between experimental and control groups. Bone contact ratio was statistically significant in the experimental group (p= 0.001). An increase in the local bone formation and bone contact ratio was observed with direct electrical stimulation of the implant and the bone area around the implant. CONCLUSION: Minimal direct electrical current, which can produce an electrical field around the implant, can increase the amount of bone formation and decrease the time of osseointegration.