Clinical, Radiographic and Pathohistological Outcomes of Hydroxyapatite (HAp) Ceramics and Dental Implants in Atrophic Posterior Maxilla

Introduction. Implant based prosthodontic rehabilitation of patients with atrophic edentulous posterior maxilla has necessity in reinforcement of alveolar bone using different bone substitutes. It is important to evaluate late outcomes in integration of synthetic HAp as biomaterial in chemical composition close to main natural bone mineral component in elevated maxillary sinus floor and osseointegration of dental implants. Aim of the study. To evaluate clinical and radiological outcomes of one stage maxillary sinus floor augmentation with synthetic HAp granules and dental implant insertion, mineralization degree of residual bone and augmented sinus part, morphological analysis of biopsies from HAp/host tissue hybrid and residual alveolar bone was performed. Materials and methods. One stage maxillary sinus floor elevation with synthetic HAp granules and 147 SEMADOS (BEGO) dental implant insertions in 70 patients were included in this study. Clinical and radiograph analyzes by dental X-rays, digital orthopantomogramms, quantitative radiodensitometry after 3 and 5 years was done. Trephine biopsies of residual alveolar bone and elevated part of maxillary sinus 6 months after implantation was done in 30 cases. Results. During this period 6 implants (4.2%) were lost. We found the decrease of radiodensity in HAp augmentated maxillary sinus area and increase of radiodensity in the area of residual alveolar bone. In biopsies after 6 months biomaterial/host tissue hybrid consisted of small bone trabecules, fibrous tissue and granules of irregular shape without inflammatory cells. Slow degradation of HAp granules by activity of osteoclast like macrophages was observed. Conclusions. Osseointegration was lost in 4.2% of inserted in augmented maxillary sinus implants. Radiodensitometry showed decrease of optical density in augmented sinus part and increase in residual alveolar bone. In biopsies of host tissue/biomaterial hybrid was bone newformation, connective tissue and biodegradation of HAp granules by osteoclast like cells.