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 su pport prosthetic restorations in the edentulous posterior maxilla. The idea l graft material is yet to be found. The present study investigated the his tologic results of a sinus augmentation procedure performed with calcium su lfate 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 t reated by modifying the application. The calcium sulfate was putty-like in consistency and placed as it hardened in layers, avoiding fluid contaminati on. The histologic samples were collected, either at 9 months, at the uncov ering 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 tech nique used in the test group produced a reduction in the graft shrinkage du ring healing, therefore slowing down the material resorption rate. Histolog ically, new bone formation with progressive lamellar maturation was found i n both groups. Some particles produced by calcium sulfate resorption were s till present after 6 months in the test group specimens, but no longer dete ctable after 9 months. Samples from the control group showed a mean histomo rphometric bone density of 34.25% +/- 10.02, while samples from the test gr oup showed a mean value of 55.54% +/- 19.82. Conclusions: The results of this study indicate that calcium sulfate appear s to be an effective material for sinus augmentation, yielding vital bone s uitable for implant integration. In addition, the technique used in the tes t group seemed to improve the quality and quantity of bone formation.