Prospective study on the augmentation of the maxillary sinus with calcium sulfate: histological results.

BACKGROUND: The main goal of the sinus elevation procedure is the formation of vital bone to allow the tissue integration of endosseous implants to support prosthetic restorations in the edentulous posterior maxilla. The ideal graft material is yet to be found. The present study investigated the histologic results of a sinus augmentation procedure performed with calcium sulfate as the grafting material. METHODS: The clinical trial consisted of 2 groups: a first (control) group of 12 patients (15 sinuses) in which the material was carefully placed but not stratified. In the second (test) group, 45 patients (50 sinuses) were treated by modifying the application. The calcium sulfate was putty-like in consistency and placed as it hardened in layers, avoiding fluid contamination. The histologic samples were collected, either at 9 months, at the uncovering procedure (for implants placed simultaneously with grafting material), or at 6 months at the time of implant insertion (for implants placed at a later stage). RESULTS: The augmentation procedure resulted in good, new tissue formation within the sinuses when clinically and radiographically evaluated. The technique used in the test group produced a reduction in the graft shrinkage during healing, therefore slowing down the material resorption rate. Histologically, new bone formation with progressive lamellar maturation was found in both groups. Some particles produced by calcium sulfate resorption were still present after 6 months in the test group specimens, but no longer detectable after 9 months. Samples from the control group showed a mean histomorphometric bone density of 34.25% +/- 10.02, while samples from the test group showed a mean value of 55.54% +/- 19.82. CONCLUSIONS: The results of this study indicate that calcium sulfate appears to be an effective material for sinus augmentation, yielding vital bone suitable for implant integration. In addition, the technique used in the test group seemed to improve the quality and quantity of bone formation.

Short-term healing following the use of calcium sulfate as a grafting material for sinus augmentation: a clinical report.

Because of the frequent lack of bone in the posterior maxilla, sinus augmentation has become a commonly practiced treatment modality. Many different materials have been used for augmenting the sinus, and the ideal graft is yet to be found. The present article reports the results of sinuses grafted with calcium sulfate in 2 patients. Bone biopsies were harvested 9 months after the augmentation procedure. In the first patient, 3 titanium threaded-cylinder implants were placed in the grafted area after 9 months, while in the second, 1 acid-etched, screw-shaped titanium implant was placed simultaneously with the graft. Light microscopic evaluation revealed new bone formation with ongoing remodeling and progressive lamellar maturation in the specimens. No remnants of the alloplastic material were detectable in any section, either within the bone or in the medullary tissue. When reevaluated at the uncovering procedure, the implants were radiographically and clinically judged to be osseointegrated. These observations suggest that, when used in the appropriate form and with the proper technique, calcium sulfate is a promising graft material for sinus augmentation, producing adequate quantity and quality of new bone for implant placement.