Integration of Bone Substituting Biomaterials in Atrophic Posterior Maxilla. Summary of the Doctoral Thesis

Abstract

In order to assess the integration of porous bioceramic bone substitutes into the posterior edentulous atrophic maxilla after maxillary sinus floor augmentation surgical procedures, a dental cone beam computed tomographic scanning of implantation area was performed, before and after integration of the biomaterial, in order to determine the radiodensity; as well as a morphological and immunohistochemical examination of residual alveolar ridge and bone/biomaterial hybrid. A database of patient examinations, treatments and post-operative observations was developed for registration purposes and for computerized analysis of the patients’ survey. The questionnaire study included 148 sinus lift patients with 294 dental implants. CB computed scans of 24 patients were analyzed before the implantation of the bone substitute biomaterials and 6-8 months after the surgeries. A histological and immunohistochemical examination of bone trepan biopsy was performed on 17 patients before biomaterial grafting and on 14 patients after sinus lift surgical procedure. When analysing the questionnaire results of 148 patients, an insigni-ficant number of post-operative complications (1%) was observed, as well as the loss of dental implants (4%). Cone beam radiographic densitometry of grafting site showed radiodensitometrically denser sinus lift site when compared to residual alveolar bone area, where radiodensitometric density has increased during this period, however this increase was not statistically significant. Biomaterial/tissue hybrid grafts in majority of cases six to eight months after grafts show biomaterial osseointegration without inflammation and connective tissue proliferation. The amount of bone morphogenetic protein, transforming growth factor beta, bone extracellular matrix proteins osteopontin and osteocalcin, degrading enzyme metalloproteinase 9, heat shock protein 70, antimicrobial protein defensin containing structures in trepan-biopsy samples before grafting and after sinus lift show no statistically significant differences. The amount of osteoprotegerin-containing structures in grafts after biomaterial placement was statistically significantly higher than in atrophic alveolar ridge before the surgical procedure. The relative frequency of apoptotic cells in grafts shows large individual variations without any statistical significance before and after grafting.