RESUMO
PURPOSE: To evaluate the peri-implant soft and hard tissue adaptation at implants with different modified surfaces and configurations. MATERIALS AND METHODS: Six Beagle dogs were used. Mandibular premolars and first molars were extracted bilaterally. After 3 months, full-thickness flaps were elevated, and two different types of trans-mucosal implants (ICX-Gold®, Medentis Medical GmbH, Dernau, Germany and SLActive®, Institute Straumann, Bern, Switzerland) and two different surfaces were randomly installed in the distal regions of one side of the mandible. Abutments were applied, and a nonsubmerged healing was allowed. After 1 month, the procedures were performed in the other side of the mandible, and after a further month, the animals were sacrificed, biopsies were collected, and ground sections prepared for histological examination. RESULTS: Similar results in marginal bone and soft tissues dimensions were observed after 1 month of healing at the two implant systems used, and no major changes could be observed after 2 months of healing. After 1 month, the percentage of new bone was 69.0% and 68.8% at ICX-Gold and SLActive surfaces, respectively. After 2 months, the percentage of new bone was 67.8% and 71.9% at ICX-Gold Medentis and SLActive surfaces, respectively. No statistically significant differences in osseointegration were found. CONCLUSION: The two implant systems used resulted in similar osseointegration after 1 and 2 months of healing.
Assuntos
Implantes Dentários , Gengiva/fisiologia , Mandíbula/fisiologia , Osseointegração/fisiologia , Cicatrização/fisiologia , Animais , Planejamento de Prótese Dentária , Cães , Gengiva/ultraestrutura , Mandíbula/ultraestrutura , Modelos Animais , Distribuição AleatóriaRESUMO
PURPOSE: The aim of this study was to evaluate bone regeneration at surgically created dehiscence buccal defects at implants placed immediately into extraction sockets (IPIES) of small dimensions filled with autogenous bone or deproteinized bovine bone mineral (DBBM) associated with a collagen membrane. MATERIALS AND METHODS: Eight Labrador dogs were used and implants were placed immediately into the extraction sockets of the second premolar. The buccal wall was subsequently removed to create a standardized defect, 4 mm wide coronally, 2 mm wide apically, and 6 mm high. Autogenous bone particles (AB) or DBBM granules were used to fill the defects. All surgical sites were subsequently covered by a resorbable collagen membrane and a non-submerged healing was allowed. After 4 months, the animals were euthanized and bone blocks harvested and processed for histomorphometric analysis. RESULTS: The bony crest at the buccal aspect (C) was located 2.3 ± 0.8 mm and 1.7 ± 0.7 mm apically to the implant shoulder (IS) at the AB and DBBM sites, respectively. The coronal levels of osseointegration at the buccal aspect (B) were located 2.7 ± 0.7 mm and 2.2 ± 1.0 mm apically to IS at the AB and DBBM sites, respectively. At the AB sites, the peri-implant mucosa was located 4.3 ± 0.9 mm, 4.7 ± 0.9 mm, and 2.0 ± 1.6 mm coronally to C, B, and IS, respectively. The corresponding values at the DBBM sites were 4.3 ± 0.6 mm, 4.8 ± 0.6 mm, and 2.5 ± 0.8 mm, respectively. No statistically significant differences were found. CONCLUSIONS: The treatment of surgically created buccal defects at IPIES sites using Bio-Oss® (Geistlich Biomaterials, Wolhusen, LU, Switzerland) or autogenous bone, concomitantly with a collagen membrane, engenders bone regeneration to a similar extent after 4 months of healing.
Assuntos
Regeneração Óssea , Substitutos Ósseos , Implantes Dentários , Carga Imediata em Implante Dentário , Alvéolo Dental/fisiologia , Animais , Bovinos , Colágeno , Cães , Modelos Animais , Mucosa Bucal/fisiologia , Mucosa Bucal/cirurgia , Alvéolo Dental/cirurgia , Transplante AutólogoRESUMO
OBJECTIVE: To compare peri-implant tissue healing at implants installed in sites prepared with conventional drills or a sonic device. MATERIAL AND METHODS: In six Beagle dogs, the mandibular premolars and first molars were extracted bilaterally. After 3 months, full-thickness muco-periosteal flaps were elevated and recipient sites were prepared in both sides of the mandible. In the right side (control), the osteotomies were prepared using conventional drills, while, at the left side (test), a sonic device (Sonosurgery(®)) was used. Two implants were installed in each side of the mandible. After 8 weeks of non-submerged healing, biopsies were harvested and ground sections prepared for histological evaluation. RESULTS: The time consumed for the osteotomies at the test was more than double compared to the conventional control sites. No statistically significant differences were found for any of the histological variables evaluated for hard and soft tissue dimensions. Although not statistically significant, slightly higher mineralized bone-to-implant contact was found at the test (65.4%) compared to the control (58.1) sites. CONCLUSIONS: Similar healing characteristics in osseointegration and marginal hard tissue remodeling resulted at implants installed into osteotomies prepared with conventional drills or with the sonic instrument (Sonosurgery(®)).
Assuntos
Implantação Dentária Endóssea/métodos , Osteotomia/métodos , Procedimentos Cirúrgicos Ultrassônicos/métodos , Cicatrização/fisiologia , Animais , Biópsia , Cães , Desenho de Equipamento , Mandíbula/cirurgia , Osteotomia/instrumentação , Retalhos Cirúrgicos , Extração Dentária , Procedimentos Cirúrgicos Ultrassônicos/instrumentaçãoRESUMO
OBJECTIVE: To compare peri-implant soft- and hard-tissue integration at implants installed juxta- or sub-crestally. Furthermore, differences in the hard and soft peri-implant tissue dimensions at sites prepared with drills or sonic instruments were to be evaluated. MATERIAL AND METHODS: Three months after tooth extraction in six dogs, recipient sites were prepared in both sides of the mandible using conventional drills or a sonic device (Sonosurgery(®)). Two implants with a 1.7-mm high-polished neck were installed, one with the rough/smooth surface interface placed at the level of the buccal bony crest (control) and the second placed 1.3 mm deeper (test). After 8 weeks of non-submerged healing, biopsies were harvested and ground sections prepared for histological evaluation. RESULTS: The buccal distances between the abutment/fixture junction (AF) and the most coronal level of osseointegration (B) were 1.6 ± 0.6 and 2.4 ± 0.4 mm; between AF and the top of the bony crest (C), they were 1.4 ± 0.4 and 2.2 ± 0.2 mm at the test and control sites, respectively. The top of the peri-implant mucosa (PM) was located more coronally at the test (1.2 ± 0.6 mm) compared to the control sites (0.6 ± 0.5 mm). However, when the original position of the bony crest was taken into account, a higher bone loss and a more apical position of the peri-implant mucosa resulted at the test sites. CONCLUSIONS: The placement of implants into a sub-crestal location resulted in a higher vertical buccal bone resorption and a more apical position of the peri-implant mucosa in relation to the level of the bony crest at implant installation. Moreover, peri-implant hard-tissue dimensions were similar at sites prepared with either drills or Sonosurgery(®).
Assuntos
Perda do Osso Alveolar/patologia , Reabsorção Óssea/patologia , Implantação Dentária Endóssea/métodos , Implantes Dentários , Mandíbula/cirurgia , Animais , Biópsia , Dente Suporte , Implantação Dentária Endóssea/instrumentação , Cães , Osseointegração , Extração DentáriaRESUMO
PURPOSE: N-butyl-2-cyanoacrylate (NB-Cn) is an alternative method for onlay graft fixation and might be efficient for preserving the graft volume. Our aim was to analyze the gene expression and mineralized tissue variations of calvarial bone grafting fixed in the mandible with either NB-Cn or a titanium screw (TiS). MATERIALS AND METHODS: New Zealand rabbits had bilateral calvarial grafts fixed at both sides of the mandible with either NB-Cn or a TiS. The rabbits were sacrificed at 4 and 8 days, and micro-computed tomography analysis was performed. For molecular analysis, the gene expression of interleukin-6, interleukin-10, and tumor necrosis factor-α was assessed. Quantification using real-time polymerase chain reaction was performed. Statistical analysis was performed using the paired Student t test (P < .05). RESULTS: Bone graft fixation with NB-Cn promoted superior volume and density preservation. The percentage of mineralized tissue at the center portion and border of the graft was very similar (NB-Cn, 50.6% ± 8.3% and 50.3% ± 10.6%, respectively) and superior than in the TiS group (32.5% ± 3.5% and 33.8% ± 6%, respectively). Genes from the NB-Cn group were upregulated compared with those in the TiS group at the initial phases of bone healing (4 days), with the profile reversed at the 8-day point. At day 8, the osteoclastogenesis-related genes were upregulated in the TiS group. CONCLUSIONS: Onlay bone grafts fixed with screws induced more inflammation during the initial remodeling process than did NB-Cn. The differences in the incorporation into the host bed suggest that the use of adhesives for graft fixation will promote superior volume and density preservation.
Assuntos
Parafusos Ósseos , Transplante Ósseo/métodos , Embucrilato/uso terapêutico , Mandíbula/cirurgia , Animais , Autoenxertos/transplante , Materiais Biocompatíveis/química , Densidade Óssea/fisiologia , Remodelação Óssea/fisiologia , Transplante Ósseo/instrumentação , Calcificação Fisiológica/fisiologia , Imageamento Tridimensional/métodos , Interleucina-10/análise , Interleucina-6/análise , Masculino , Osteoclastos/patologia , Coelhos , Distribuição Aleatória , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Tempo , Titânio/química , Fator de Necrose Tumoral alfa/análise , Cicatrização/fisiologia , Microtomografia por Raio-XRESUMO
OBJECTIVES: To evaluate the influence on osseointegration of Deproteinized bovine bone mineral (DBBM) particles used to fill defects of at least 1 mm around implants having no primary contact with bone. MATERIAL AND METHODS: Premolars and first molars were extracted bilaterally from the mandible of six Labrador dogs. After 3 months of healing, mucoperiosteal full-thickness flaps were elevated, and one recipient site was prepared in the molar region of each hemi-mandible to place implants. These were installed with a deliberate circumferential and periapical space to the bone walls of 1.2 mm. All implants were stabilized with passive fixation plates to maintain the implants in situ and without any contact with the implant bed. The control sites were left to be filled with coagulum, while at the test sites, the residual gap was filled with DBBM. After 3 months of submerged healing, the animals were sacrificed. Ground sections were prepared and analyzed histomorphometrically. RESULTS: Mineralized bone-to-implant contact was 4.0% and 3.9% for control and test sites, respectively. The width of the residual defects was 0.48 mm and 0.88 mm at the control and test sites, respectively. The percentage of implant surface covered by a layer of dense connective tissue of 0.12 mm of width on average was 84.9% and 88.5% at the control and test sites, respectively. CONCLUSION: A minor and not predictable degree of contact or distance osteogenesis was obtained on the implant surface when primary contact of the implant surface with the implant bed had deliberately been avoided. DBBM grafting of the artificial gap did not favor osseointegration. Neither did it enhance the ability to bridge the gap with newly formed bone in an artificial defect wider than 1 mm.
Assuntos
Implantação Dentária Endóssea/métodos , Minerais/farmacologia , Osseointegração , Animais , Bovinos , Implantes Dentários , Planejamento de Prótese Dentária , Cães , Mandíbula/cirurgia , Osteogênese , Propriedades de Superfície , Retalhos Cirúrgicos , Extração Dentária , CicatrizaçãoRESUMO
OBJECTIVE: To compare immediate and staged approach implant placement in circumferential defects treated with deproteinized bovine bone mineral (DBBM); hidroxyapatite/tricalcium phosphate (HA/TP); autogenous bone (Ab); and coagulum (Cg); upon implant stability, osseointegration and alveolar crest maintenance. MATERIALS AND METHODS: Six dogs underwent extractions of lower premolars, bilaterally. Twelve weeks later four bone defects (6 mm wide/4 mm long) were drilled at one side and randomly filled with DBBM; HA/TP; Ab; and Cg, respectively, and left to heal (staged approach). Eight weeks later one implant (Osseospeed(™) , AstraTech) was placed in experimental sites. At the same session four defects were drilled on contra-lateral side and implants were inserted immediately after biomaterials grafting (immediate approach). Animals were euthanized 8 weeks later. Implant stability was measured by resonance frequency analysis (RFA) at installation and after sacrifice. Ground sections were prepared for bone contact (BIC); bone area (BA); distance implant shoulder-bone crest (IS-C); distance implant shoulder first bone contact (IS-B); and areas occupied by soft tissue. RESULTS: The BA and BIC were superior in the staged approach. The Cg exhibited higher BIC and BA as compared with other materials at the total implant body (P = 0.004 and 0.012, respectively). The DBBM, HA/TP and Ab groups rendered similar BA and BIC. The immediate approach resulted in less crest resorption compared to staged approach. The biomaterials did not affect the IS-C and IS-B measurements. Particles area tended to be higher in DBBM group than HA/TP (P = 0.15), while soft tissue infiltrate was higher in DBBM group when used in the immediate approach (P = 0.04). The RFA indicated gain in stability in the staged approach (P = 0.002). The correlation test between RFA vs. BIC and BA demonstrated inferior stability for DBBM group in immediate approach (P = 0.01). CONCLUSIONS: Implants placed in healed defects resulted in better stability as a consequence of higher BIC and BA. The Cg alone rendered increased BIC compared to other materials in both approaches. Immediate approach should be preferable to staged approach in terms of alveolar crest maintenance. The BIC and BA values did not vary between micro and macro-threads in this experimental model. Implants installed in sites filled with DBBM in immediate approach were less stable.
Assuntos
Substitutos Ósseos/farmacologia , Proteínas do Esmalte Dentário/farmacologia , Implantação Dentária Endóssea/métodos , Implantes Dentários , Hidroxiapatitas/farmacologia , Mandíbula/cirurgia , Minerais/farmacologia , Osseointegração , Perda do Osso Alveolar/prevenção & controle , Animais , Transplante Ósseo/métodos , Cães , Carga Imediata em Implante Dentário , Masculino , CicatrizaçãoRESUMO
AIM: To evaluate the healing at implants with a moderately rough surface placed and stabilized in recipient sites of dimensions deeper and larger than that of the implants to avoid any contact between parent bone and the implant. MATERIAL & METHODS: In six Labrador dogs, premolars and first molars were extracted bilaterally in the mandible. After 3 months of healing, mucoperiosteal full-thickness flaps were elevated and the premolar area of the alveolar bony crest was selected. Three recipient sites were prepared to place three implants. One implant was used as control. The other two were placed in recipient sites which left a circumferentially and periapical prepared defect of 0.7 mm (small) and 1.2 mm (large), respectively. All implants were stabilized with passive fixation plates to maintain the implants stable and without any contact with the implant bed. After 3 months of submerged healing, the animals were sacrificed. Ground sections were prepared and analyzed histomorphometrically. RESULTS: The BIC% was 5.3% and 0.3% for implants placed in small and large defect sites, respectively, whereas it was 46.1% for control implants. The differences were statistically significant. The width of the residual defects was 0.4 and 0.5 mm at the small and large defects, respectively. An approximately 0.09 mm layer of dense connective tissue (DCT) rich in fibers and fibroblast-like cells was observed adherent to the implant surfaces. The percentage of implant surface covered by DCT was 92.8% and 95.6% at the small and large defects, respectively. CONCLUSION: Osseointegration was observed at the test sites, and the dimensions of the defects influenced the outcomes. However, the degree of osseointegration at both small and large defects was very low compared with the control sites.
Assuntos
Implantação Dentária Endóssea/métodos , Implantes Dentários , Osteogênese , Animais , Planejamento de Prótese Dentária , Cães , Mandíbula/cirurgia , Osseointegração , Propriedades de Superfície , Titânio , Extração Dentária , CicatrizaçãoRESUMO
AIM: To evaluate the effect of a space-maintaining device fixed to the lateral wall of the maxillary sinus after the elevation of the sinus mucosa on bone filling of the sinus cavity. MATERIAL AND METHODS: Immediately after the elevation of the maxillary sinus Schneiderian membrane accomplished through lateral antrostomy in four monkeys, a titanium device was affixed to the lateral sinus wall protruding into the sinus cavity to maintain the mucosa elevated without the use of grafting material. The healing of the tissue around the implants was evaluated after 3 and 6 months. Ground sections were prepared and analyzed histologically. RESULTS: The void under the elevated sinus membrane, originally filled with the blood clot, was reduced after 3 as well as after 6 months of healing of about 56% and 40.5%, respectively. In seven out of eight cases, the devices had perforated the sinus mucosa. The formation of mineralized bone and bone marrow amounted to about 42% and 69% after 3 and 6 months, respectively. The connective tissue represented about 53% and 23% of the newly formed tissue after 3 and 6 months, respectively. CONCLUSIONS: New bone formation was found below the devices. However, shrinkage of the newly formed tissue was observed both after 3 and 6 months of healing. Hence, the space-maintaining function of the devices used in the present study has to be questioned.
Assuntos
Seio Maxilar/cirurgia , Mucosa Nasal/cirurgia , Procedimentos Cirúrgicos Pré-Protéticos Bucais/instrumentação , Levantamento do Assoalho do Seio Maxilar/métodos , Animais , Cebus , Masculino , Osteogênese , Retalhos Cirúrgicos , Técnicas de Sutura , TitânioRESUMO
AIM: To evaluate the integration of implants installed using a surgical guide in augmented sites with autologous bone or deproteinized bovine bone mineral (DBBM) blocks, concomitantly with a collagen membrane. MATERIAL AND METHODS: Mandibular molars were extracted bilaterally in six Labrador dogs, the buccal bony wall was removed, and a box-shaped defect was created. After 3 months, flaps were elevated, a bony graft was harvested from the ascending ramus, and secured to the lateral wall of the defect by means of screws. In the left mandibular side, a DBBM block was fixed into the defect. A resorbable membrane was applied at both sides, and the flaps were sutured. After 3 months, flaps were elevated, and a customized device was used as surgical guide to prepare the recipient sites in the interface between grafts and parent bone. One implant was installed in each side of the mandible. After 3 months, biopsies were harvested, and ground sections were prepared for histologic evaluation. RESULTS: One autologous bone block graft was lost before implant installation. The width of the alveolar crest at the test sites (DBBM) was 5.4 ± 1.2 mm before, 9.4 ± 1.2 mm immediately after grafting, and 9.3 ± 1 mm at implant installation. At the control sites (autologous bone), the corresponding values were: 5.2 ± 1, 9 ± 1.2, and 8.7 ± 0.9 mm, respectively. All implants installed were available for histologic evaluation (n = 5). The autologous bone grafts, rich in vessels and cells, were integrated in the parent bone, and only little non-vital bone was found. The BIC% was 56.7 ± 15.6% and 54.2 ± 13.2% at the buccal and lingual aspects, respectively. At the test sites, the DBBM appeared to be embedded into connective tissue, and very little newly formed bone was encountered within the grafts. The BIC% was 5.8 ± 12.3% and 51.3 ± 14.2% at the buccal and lingual aspects, respectively. CONCLUSIONS: Autologous bone blocks used to augment the alveolar bony crest horizontally allowed the complete osseointegration of implants installed after 3 months of healing. However, similar blocks of DBBM did not promote osseointegration, although the installed implants were stable owing to the osseointegration in the sites of the parent bone.