RESUMO
BACKGROUND: The efficacy of human freeze-dried bone (h-FDB) as particulate vs block forms as a proper onlay augmented bone graft material to accommodate implants is undetermined. PURPOSE: To evaluate osseointegration and new bone formation at implants placed in FDB blocks (BL group) and those at the adjunction of particulate FDB (PR group). MATERIALS AND METHODS: Twelve pairs of h-FDB blocks were stabilized bilaterally to the calvaria of 12 rabbits. Twenty-four SLA implants were placed at the remodeled grafted blocks, 4 months later. A circumferential gap was created around one implant in each pair and packed with particulate h-FDB. Section biopsies were obtained at 2-month post implant placement (6 months post-block grafting). Bone-to-implant contact (BIC) and bone-area fraction (BAF) were histomorphometrically calculated. RESULTS: The mean BIC was 34.4% and 33.5% for the BL and PR groups, respectively. The mean BAF was 23.9% and 26.4% for the corresponding groups, respectively. Osseointegration and newly formed bone were evident mostly between the threaded portions of the implants in proximity to the host rabbit calvaria compared to its cervical neck. CONCLUSION: The particulate and the cancellous block h-FDB forms yielded similar BIC and BAF outcome. Full revascularization/revitalization is questioned.
Assuntos
Implantação Dentária Endóssea , Implantes Dentários , Animais , Transplante Ósseo , Liofilização , Humanos , Osseointegração , Osteogênese , CoelhosRESUMO
PURPOSE: To assess the extent of osseointegration with rough-surface implants and new bone formation (NBF) within human freeze-dried bone blocks (h-FDB) grafted over rabbit calvaria. MATERIALS AND METHODS: A total of 18 rectangular h-FDB blocks were stabilized bilaterally to the calvaria of nine New Zealand rabbits by two mini titanium screws each. A total of 18 rough-surface implants (5.0 × 6.0-mm) were placed, 9 simultaneously (immediate placement [IP]) on one side and 9 at 3 months after block grafting (delayed placement [DP]) on the contralateral side. At 12 weeks after the second surgical procedure, block biopsies were harvested and processed for histologic analysis. Morphometric measurements consisted of bone-to-implant contact (BIC) and the extent of NBF from the calvarial surface and outward into the block. A paired t test was applied for statistical analysis. RESULTS: All h-FDB blocks were integrated, and the implants showed clinical stability. Histologically, the BIC was primarily between the apical end of the implants and the host rabbit calvaria. Bone growth between the implant threads was minimal and inconsistent among all animals. Morphometric measurements showed that the mean BIC of the IP and DP implants with the blocks was 10.50% ± 5.99% and 23.06% ± 9.58%, respectively (P < .001). NBF was observed primarily in the cancellous compartment of the block adjacent to the recipient calvarial bed. The extent of NBF into the block around the IP and DP implants was 9.95% ± 8.41% and 12.90% ± 11.07%, respectively (P = 0.2). CONCLUSION: In this model, a significantly lower BIC was demonstrated when implants were placed simultaneously with h-FDB block grafting compared to those placed in a two-stage mode. However, both techniques showed limited osseointegration.
RESUMO
OBJECTIVES: Clinico-pathological evaluation of bisphosphonate (BP)-related osteonecrosis of jaws, comparison between oral (PO) and intravenous (IV) BPs and histomorphometric analysis of associated actinomyces. STUDY DESIGN: Retrospective clinical and histomorphometric analysis. Data on background, clinical, treatment and follow-up were analyzed. Actinomyces colonies were identified by typical filamentous colony morphology, Gram, and PAS stains. Colony density and relative colony surface area were measured. RESULTS: Fifty-two patients were included, 37 (71.2%) IV, 15 (28.8%) PO BPs. with a mean duration of 2.33 and, 4.33 years respectively. One hundred percent of cases exhibited actinomyces colonization. The relative colony surface area was significantly higher in PO treatment (P = .024), with no differences in density, healing time or antibiotic treatment periods. High frequency of diabetes mellitus (60% PO cases) and corticosteroid treatment (25% of cases) were recorded. CONCLUSION: Infection with actinomyces is a common denominator in BP-related osteonecrosis of the jaws (BRONJ), regardless of administration route. Diabetes and corticosteroid treatment seem to be important contributing factors for BRONJ.
