Predictive factors for maxillary sinus augmentation outcomes: a case series analysis.

AIM: To determine the influence of different local and systemic factors on histologic, histomorphometric, and radiographic outcomes after maxillary sinus augmentation. MATERIALS AND METHODS: Fifty-two sinus augmentation procedures were performed. Grafting material consisted of a mixture of anorganic bovine bone (ABB) and autogenous bone. After 6 months, bone core biopsies were harvested from implant sites for histologic and histomorphometric analyses. Data regarding age, gender, type of edentulism, alcohol consumption, smoking habits, and history of periodontal disease were recorded and statistically analyzed. RESULTS: Histomorphometric analyses revealed the presence of 35.75% ± 16.42% of vital bone, 40.56% ± 16.23% of nonmineralized tissue, and 23.69% ± 18.23% of residual ABB particles. Radiographic vertical bone resorption inversely correlated with residual ABB. A significant difference in bone resorption patterns was observed for completely edentulous patients and for those with a history of periodontitis. Tobacco and alcohol negatively influenced vital bone formation after sinus augmentation. Implant and prostheses survival after 2 years of functional loading was not directly affected by patient's individual habits. CONCLUSION: Certain patient-related variables such as history of periodontitis, type of edentulism, or smoking/drinking habits play an important role in bone graft maturation after maxillary sinus floor elevation.

Effect of anorganic bovine bone to autogenous cortical bone ratio upon bone remodeling patterns following maxillary sinus augmentation.

INTRODUCTION: Maxillary sinus augmentation is a predictable implant site development technique, although several local and systemic factors may influence outcomes. The aim of this study was to evaluate healing patterns and bone remodeling activity following the use of two different graft mixtures for maxillary sinus augmentation. MATERIALS AND METHODS: Patients in need of maxillary sinus augmentation were randomly assigned to two different groups. A graft mixture using a 50% autologous bone (AB) to 50% anorganic bovine bone (ABB) ratio was used in group 1, while a 20% AB to 80% ABB ratio was utilized for group 2. After a 6-month healing period, bone core biopsies were harvested for histological, histomorphometrical, and immunohistochemical analyses. RESULTS: Twenty-eight subjects participated in this study. No statistically significant differences were found between groups in regards to vital bone and non-mineralized tissue proportions. Higher number of osteoid lines (18.05 ± 10.06 in group 1 vs. 9.01 ± 7.53 in group 2; P = 0.023) and higher cellularity, particularly regarding the number of osteocytes (631.85 ± 607.98 in group 1 vs. 219.08 ± 103.26 in group 2; P = 0.002), were observed in specimens from group 1. Differences in expression patterns of osteopontin and tartrate-resistant acid phosphatase were also detected between groups. CONCLUSION: AB to ABB ratio appears to influence bone remodeling patterns and cell content following maxillary sinus augmentation procedures. Similar proportion of vital bone was found in specimens obtained from both groups. More cellular presence was observed in samples containing higher proportions of AB.

The influence of the bucco-palatal distance on sinus augmentation outcomes.

BACKGROUND: Maxillary sinus augmentation is one of the most reliable implant site development options to increase vertical bone height. However, graft consolidation requires adequate angiogenesis and migration of cells involved in osteogenesis and bone remodeling. It is speculated that these biologic events are greatly determined by the dimensions of the maxillary sinus cavity. Hence, the purpose of this study is to assess the influence of the distance from the lateral to the medial wall of the maxillary sinus on the outcomes of sinus augmentation procedures. METHODS: A total of 25 patients in need of sinus augmentation were recruited for the study. After initial examination, customized radiographic and surgical guides were fabricated and a cone-beam computerized tomography scan was obtained per patient. The bucco-palatal distance (BPD) was measured at 8, 10, and 12 mm from the alveolar crest. Sinus grafting was performed by a lateral window approach using a particulated allograft material. Patients were followed-up for 6 months. At the time of implant placement, bone core biopsies were harvested using the radiographic-surgical guide. Sections of the bone cores at 8, 10, and 12 mm from the alveolar crest were histomorphometrically analyzed. The proportion of vital bone (%VB) was correlated with the BPD using a statistical model. RESULTS: Twenty-one patients underwent sinus augmentation for a total of 24 sinuses; however, the data analyzed contained only one sinus per patient. One sinus developed an infection after grafting, resulting in a 96% success rate for the sinus grafting procedure. Twenty sinuses were used in the final statistical analysis. Histomorphometric analysis revealed that mean %VB was 22.71 +/- 19.08, mean percent of remaining allograft was 23.39 +/- 20.85, and average percent of non-mineralized connective tissue was 53.90 +/- 13.23. Analysis of the correlation between %VB and BPD by linear regression, using the actual values of BPD showed a strong negative association (R(2) = 0.141; P <0.001). CONCLUSION: The findings suggest that the %VB formation after maxillary sinus augmentation is inversely proportional to the sinus BPD.

Histomorphometric comparison of maxillary pristine bone and composite bone graft biopsies obtained after sinus augmentation.

INTRODUCTION: Sinus grafting is a technique oriented to facilitate implant placement in posterior atrophic maxillae. Several modifications of the original technique and a wide variety of materials have been proposed; most of them associated with implant survival rates. However, the quality of the bone obtained after the application of certain grafting materials has not been fully elucidated yet. The aims of this multicenter study were to analyse histomorphometrical samples obtained 6 months after sinus grafting using a composite graft consisting of anorganic bovine bone (ABB)+ autologous bone (AB), and to compare these samples with maxillary pristine bone biopsies. MATERIAL AND METHODS: Ninety maxillary sinus augmentations were performed for delayed implant placement (N = 90) in 45 consecutive patients (test group). Bone cores were harvested 6 months after grafting for histomorphometric and ultrastructural study. Control pristine bone biopsies were taken from the posterior maxilla of 10 patients (control). Bone radiographic changes were assessed up to 24 months after implant loading. RESULTS: The total mean values after analysis of test cores revealed a proportion of 46.08 + or - 16.6% of vital bone, 42.27 + or - 15.1% of non-mineralized connective tissue, and 37.02 + or - 25.1% of the remaining ABB particles. Significant bone remodeling activities were noticed in sinus grafting samples when compared with pristine bone. A statistically significant difference was observed in the number of osteoid lines between two groups, with higher values in the test one (15.1 + or - 11.48% vs. 2.5 + or - 2.2%, P = 0.0005). Ultrastructural study showed that vital trabecular bone was in intimal contact with ABB particles. Radiographic analysis revealed that the higher the proportion of remaining ABB, the lower the total vertical resorption of the graft. CONCLUSION: Sinus grafting constitutes an excellent model for the study of de novo bone formation patterns and graft consolidation, when a combination of different bone substitutes is applied. The combination of ABB+AB yields highly satisfactory outcomes from both a clinical and a histologic perspective.