RESUMO
PURPOSE: The aim of this prospective study was to investigate the two-year outcomes following immediate loading of mono-cortically engaged implants. MATERIALS AND METHODS: Thirty healthy mandible edentulous patients with an average age of 67.3 years and presenting with sufficient bony ridge at the mandible symphysis were included in the study. Four Astra Tech, Ti-Oblast® implants were installed between the mental foramina using the mono-cortical anchorage technique. The primary stability of the implants was assessed by resonance frequency analysis (RFA). After uni-abutments were placed, a temporary bridge was constructed and fixed the same day. The definitive bridges were installed 6 weeks after implant surgery. Five of 120 placed implants were lost in four patients during the first 6 weeks and these patients were excluded from the follow-up. The changes in marginal bone level (n = 20) were evaluated in Brazilian and Swedish groups at baseline, 6 weeks, 6 months, 12 months and 24 months. The RFA (n = 30) was evaluated at baseline, 6 weeks, 6 months, 12 months and 24 months postoperatively. RESULTS: Compared with baseline measurements, the postoperative values for marginal bone level (6 weeks, 6 months, 12 months and 24 months) were significantly reduced (p < 0.05), while no differences were observed in the RFA analysis (12 months and 24 months). CONCLUSIONS: The immediate loading of mono-cortically engaged implants in the edentulous mandible is safe and predictable and implant stability remains excellent after 2-year follow-up.
Assuntos
Força de Mordida , Implantação Dentária Endóssea/métodos , Mandíbula/cirurgia , Boca Edêntula/cirurgia , Complicações Pós-Operatórias/fisiopatologia , Suporte de Carga/fisiologia , Idoso , Prótese Dentária Fixada por Implante , Prótese Parcial , Feminino , Seguimentos , Humanos , Masculino , Mandíbula/fisiopatologia , Boca Edêntula/fisiopatologia , Estudos ProspectivosRESUMO
The aim of the present study was to evaluate the effect of the placement of titanium granules in fresh extraction sockets on early bone formation. The mesial roots of the third maxillary premolars of five adult beagle dogs were removed. On one side of the maxilla (Test group) the fresh extraction socket was grafted with titanium granules, while the contra-lateral socket was left non-grafted (Control group). After 1 month of healing, the dogs were euthanized and biopsies were obtained. The healing tissues were described, and histometric measurements were performed to obtain the percentage area occupied by connective tissue, new mineralized bone, bone marrow, and biomaterial particles. After 1 month of healing the findings from the histological examination revealed the titanium graft to be well incorporated into the provisional connective tissue or newly formed woven bone. The histometric measurements showed, however, that less mineralized bone was formed in the Test group than in the Control group. The present study suggests that the use of titanium granules in fresh extraction sockets was conducive to new bone formation. The graft of titanium granules seems, however, to delay the early phase of the healing process.
Assuntos
Processo Alveolar/fisiologia , Consolidação da Fratura , Osteogênese/efeitos dos fármacos , Titânio , Processo Alveolar/anatomia & histologia , Animais , Bochecha/anatomia & histologia , Cavidade Pulpar/anatomia & histologia , Cavidade Pulpar/fisiologia , Cães , Tecido de Granulação/efeitos dos fármacos , Inflamação/patologia , Pós , Língua/anatomia & histologiaRESUMO
PURPOSE: The aim of the present study was to investigate the healing, integration, and maintenance of autogenous onlay bone grafts and implant osseointegration either loaded in the early or the delayed stages. MATERIALS AND METHODS: A total of 5 male dogs received bilateral blocks of onlay bone grafts harvested from the contralateral alveolar ridge of the mandible. On one side, the bone block was secured by 3 dental implants (3.5 mm x 13.0 mm, Osseospeed; AstraTech AB, Mölndal, Sweden). Two implants at the extremities of the graft were loaded 2 days after installation by abutment connection and prosthesis (simultaneous implant placement group); the implant in the middle remained unloaded and served as the control. On the other side, the block was fixed with 2 fixation screws inserted in the extremities of the graft. Four weeks later, the fixation screws were replaced with 3 dental implants. The loading procedure (delayed implant placement group) was performed 2 days later, as described for the simultaneous implant placement sites. The animals were sacrificed 12 weeks after the grafting procedure. Implant stability was measured through resonance frequency analysis. The bone volume and density were assessed on computed tomography. The bone to implant contact and bone area in a region of interest were evaluated on histologic slides. RESULTS: The implant stability quotient showed statistical significance in favor of the delayed loaded grafts (P = .001). The bone-to-implant contact (P = .008) and bone area in a region of interest (P = 0.005) were significantly greater in the delayed group. Nevertheless, no difference was found in terms of graft volume and density between the early loaded and delayed-loaded approaches. CONCLUSIONS: The protocol in which the implant and bone graft were given delayed loading allows for effective quality of implant osseointegration and stabilization, with healing and remodeling occurring in areas near the implant resulting in denser bone architecture.
Assuntos
Aumento do Rebordo Alveolar/métodos , Transplante Ósseo , Implantação Dentária Endóssea , Prótese Dentária Fixada por Implante , Osseointegração , Análise de Variância , Animais , Densidade Óssea , Parafusos Ósseos , Dente Suporte , Retenção em Prótese Dentária , Análise do Estresse Dentário , Cães , Masculino , Probabilidade , Estatísticas não Paramétricas , Fatores de Tempo , Tomografia Computadorizada por Raios X , VibraçãoRESUMO
BACKGROUND: Previous experimental studies on onlay bone graft integration have shown either advantages or disadvantages to the use of mechanical barriers. This indicates that the role played by the biologic properties of transplanted bone and membrane in graft revascularization and bone remodeling has not yet been established. The outcomes regarding osseointegration of titanium dental implants applied in such a condition are still contradictory. PURPOSE: The rabbit's radius model that is grafted onto the mandibular lower border and covered by membrane can reproduce a challenging experimental situation to preliminarily study the factors involved in osseointegration under deprived blood vessels source. MATERIALS AND METHODS: Fourteen New Zealand White rabbits had a 2.5-cm segment of the right radius osteoectomized and fixed onto the right mandibular lower border using titanium screws. Two screw-shaped titanium implants (2.5 mm wide yen 2.5 mm long) were installed 7 mm apart in the mid length of the grafted bone. In experimental sites, the graft with the implants and graft-host bone junction were covered by expanded polytetrafluoroethylene (e-PTFE) membrane; control sites were left uncovered. Eight animals from the experimental group and six animals from the control group were sacrificed at 6 and 24 weeks after surgery. Ground sections obtained from en bloc tissues containing graft, implants, and recipient bone were subjected to histologic evaluation and histomorphometric analysis (area occupied by the graft and bone-to-implant contact). RESULTS: The graft showed significantly more resorption after 24 weeks than at 6 weeks (p < or =.05) irrespective of the treatment (with or without membrane), although the amount of new bone was greater at 24 weeks in sites where a membrane was covering the graft. Compared with 6 weeks postoperatively, the bone-to-implant contact was considerably improved at 24 weeks (p < or =.05), and the membrane seemed beneficial for implant osseointegration when compared with unprotected sites (p .05). As a result of graft resorption, the amount of soft tissue was considerably expanded in sites beneath membrane, accompanied by a sustained process of trabecular bone deposition close to the barrier. CONCLUSIONS: Cortical onlay grafts covered by membrane demonstrated delayed remodeling, probably as a consequence of a hindered process of graft revascularization. Grafts covered by membrane might rely on previous host bone resorption both to become revascularized and to remodel. The findings that the membrane-protected grafts were most resorbed at 24 weeks might be attributable to better implant osseointegration, because the fixtures were exposed to greater mechanical stimulation in these sites. key words: bone regeneration, implant osseointegration, onlay bone-graft
Assuntos
Transplante Ósseo/fisiologia , Implantes Dentários , Membranas Artificiais , Osseointegração , Animais , Remodelação Óssea/fisiologia , Reabsorção Óssea/patologia , Parafusos Ósseos , Transplante Ósseo/patologia , Feminino , Sobrevivência de Enxerto , Mandíbula/patologia , Mandíbula/cirurgia , Modelos Animais , Neovascularização Fisiológica/fisiologia , Osteogênese/fisiologia , Politetrafluoretileno , Coelhos , Estatísticas não Paramétricas , Fatores de Tempo , Titânio , CicatrizaçãoRESUMO
BACKGROUND: Since the discovery of bone morphogenetic proteins (BMPs), the number of related studies has increased substantially, and more recent outcomes have cast encouraging perspectives on their use in reconstructive surgery. PURPOSE: The aim of the present review was to summarize the present knowledge about the use of BMPs in conjunction with dental implants based on the literature. MATERIALS AND METHODS: Scientific articles dealing with the use of growth factors and bone healing with or without dental implants were searched for on MEDLINE and critically scrutinized. RESULTS: Thirty-nine scientific reports formed the base for the present review. Whereas the osteoinductive capability of BMPs is well documented, studies on their effects in implant dentistry are still incipient. Preclinical and clinical studies did not show outstandingly good outcomes of the application of BMPs compared with conventional treatments or controls. CONCLUSIONS: The number of studies in the field of dental implantology in which BMPs have been used is still too small for establishing clinical protocols of their use in order to improve a recipient bone bed prior to implant placement or to enhance the integration process of an implant.