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

ABSTRACT

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.