Maxillary Sinus Elevation by Crestal Window: Influence of 3D Sinus Size on Bone Regeneration-A Retrospective Clinical and Histologic Evaluation.

This evaluation correlates maxillary sinus 3D morphology with bone regeneration. In 39 patients with crestal bone ≤ 2 mm, mineralized human bone allografts were used to augment the sinus floor through the crestal window sinus elevation approach. CBCT was used to measure the buccopalatal diameter (BPD), mesiodistal diameter (MDD), and hemi-ellipsoidal volume (Vh) in all sinuses. A bone core biopsy sample was taken at implant placement (4 to 5 months after sinus augmentation). Microradiographs of methacrylate-embedded sections were used to evaluate the amounts of bone, residual graft, and soft tissue. All 51 implants placed in the 39 patients successfully osseointegrated. A linear regression analysis showed that as BPD, MMD, and Vh increased, the amount of bone gain decreased and the amount of soft tissue increased (P < .05). The amount of residual graft was little affected by sinus morphology. Microradiographic data were grouped into four different sinus types (from small to great) using BPD and Vh medians. The best amount of bone formation was achieved in the narrow and short sinus type, while no great differences were found in the remaining three sinus types. Understanding of 3D sinus cavity morphology, especially the buccopalatal diameter and mesiodistal dimensions, is fundamental for achieving the best possible sinus augmentation outcomes.

Maxillary Sinus Floor Augmentation with Porcine-Apatite Xenograft: A Prospective Case Series Study.

This study clinically and histologically evaluated the outcome of a porcineapatite xenograft used to elevate the maxillary sinus floor in a severely atrophic ridge. A two-stage crestal window sinus elevation protocol was conducted in 24 patients with crestal bone ≤ 2 mm. Highly porous porcine carbonate apatite moistened with saline solution was placed in the elevated sinus cavity as the sole grafting material. Bone core biopsy samples were taken at 6, 9, and 12 months after sinus augmentation surgery (at implant placement). Treatment outcomes were assessed using microCT (µCT) and histologic analysis. Statistical analysis was performed using nonparametric Kruskal-Wallis test, followed by post-hoc Dunn multiple comparison test. At 6 months after implant placement, all implants achieved good primary stability (insertion torque ≥ 30 Ncm) and successfully osseointegrated. The residual graft amount (mean ± SE) was low (11.91% ± 1.99%) at 6 months and further decreased (6.11% ± 2.64%) by 12 months. On the contrary, the amount of new bone detected was 18.94% ± 4.08% at 6 months and was significantly (P < .05) increased (40.16% ± 5.27%) at 12 months. Histologic assessment revealed osteoclasts actively resorbing the graft as well as osteoblasts actively forming new bone. In the severely atrophic maxilla, the porcine-apatite xenograft promotes new bone formation while being slowly absorbed. Within the limited sample size, the porcine-apatite xenograft seems to be a good graft material for crestal window sinus augmentation.

Cortical Versus Cancellous Solvent-Dehydrated Bone Allograft for Alveolar Ridge Preservation: A Histologic Study.

Allografts have been routinely used for immediate grafting of extraction sites as modalities of alveolar ridge preservation (ARP). Solvent-dehydrated bone allograft (SDBA), which is commonly utilized for socket grafting, exists in the form of cortical and cancellous particles. This study aims to provide a histologic comparison of cortical and cancellous SDBA for ARP. A total of 35 extraction sockets were allocated to receive either a cortical (17 sites) or cancellous (18 sites) SDBA, followed by application of a resorbable collagen wound dressing in both groups. At approximately 4 months, a bone core biopsy sample was obtained during implant placement. Histomorphometric assessment was then conducted to compare the differences between both forms of SDBA. Within its limitations, a higher percentage of vital bone was observed in the cortical bone group compared to the cancellous bone group (28.6% vs 20.1%, respectively, P = .042), while there was a lack of statistically significant differences among other fractions of the bone biopsy sample (residual graft particles and nonmineralized tissues such as connective tissue or other components).

Topographic Assessment of Calcified Material After Sinus Floor Augmentation.

PURPOSE: This study aimed to topographically examine the healing of mineralized human bone allograft in sinus augmentation. MATERIALS AND METHODS: Thirty-two patients with crestal bone height ≤ 2 mm who required sinus augmentation were recruited for the study. A mixture of 80/20 cortical/cancellous mineralized human bone allografts were used to augment the sinus floor using a crestal window approach. A bone core biopsy specimen was taken at the time of implant placement, 6 months after surgery. Microradiographs of methacrylate-embedded sections were split into five longitudinal sectors (crestal to sinusal) to topographically assess the bone, graft, and fibrous tissue amount. RESULTS: All implants were osseointegrated 3 months later without any adverse effects. The polynomial (degree 2) of results (all with great correlation coefficient, P < .01) gave rise to a polynomial curve of graft percentage with a maximum at sector 4 (presinusal), a bone percentage with a minimum between sectors 3 and 4, and a fibrous tissue percentage with a maximum between sectors 3 and 4. CONCLUSION: Based upon topographic analysis, mineralized human bone allograft is capable of achieving adequate vertical bone height for implant placement. The need for a topographic analysis to assess the outcomes of sinus augmentation is emphasized.

Crestal Window Sinus Lift and Its Long-Term Clinical Outcomes.

Sinus augmentation has been shown to be an effective methodology to augment a deficient maxillary sinus. However, there are many techniques a clinician can choose from. Historically, lateral window or crestal osteotome approaches were the most frequently discussed techniques. In this paper, a sinus floor elevation technique with crestal window sinus lift was proposed to treat cases of extremely atrophic maxillae (remaining bone height ≤ 2 mm). A crestal window is opened for the sinus membrane to be detached from the bony walls. After the proper elevation and membrane detachment, human particulated allografts were placed via the crestal access window to elevate the sinus membrane. Primary closure was then achieved, and after 6 to 9 months of healing, implant placement was performed. From the long-term clinical outcome that was obtained, the authors concluded that crestal window sinus lift is a procedure with predictable outcomes for lifting a maxillary sinus floor less than 2 mm thick, with an average elevation height of 11.73 mm.