Exosome-loaded injectable hydrogel for repairing bone defects around implants / 中国组织工程研究

BACKGROUND:A large number of studies have confirmed that exosomes can promote osteogenesis and vascularization.However,simple exosome therapy has problems such as poor targeting,and the content of loaded molecules cannot reach the therapeutic concentration. OBJECTIVE:To load exosomes into injectable gluconolactone-sodium alginate β-tricalcium phosphate-polyethylene glycol hydrogel,and observe the effect of the hydrogel on peri-implant bone defect in vivo and in vitro. METHODS:Exosomes were extracted from bone marrow mesenchymal stem cells and wrapped in injectable gluconolactone-sodium alginate β-tricalcium phosphate-polyethylene glycol hydrogel.(1)In vitro experiment:The hydrogel loaded with exosomes and the hydrogel without exosomes were cocultured with endothelial progenitor cells,and exosomes uptake experiment,tubule formation experiment,cell proliferation,migration ability,and angiogenic gene detection were carried out.(2)In vivo experiment:Twelve male New Zealand white rabbits were used to prepare two standard implant cavities and corresponding bone defects in the long axis of one femur.A hydrogel loaded with exosomes was implanted in the bone defect after an implant was implanted in a cavity at the proximal end of the implant(experimental group),and an unloaded exosome hydrogel was implanted in the bone defect after an implant was implanted in a cavity at the distal end of the implant(control group).At 3,6 and 9 weeks after operation,bone defects with implants were removed and stained with hematoxylin-eosin staining and Masson staining.Simultaneously,osteogenic and angiogenic genes were detected at 9 weeks after operation. RESULTS AND CONCLUSION:(1)In vitro experiment:Exosomes could enter endothelial progenitor cells.The proliferation,migration,angiogenesis and gene(CD31,vascular endothelial growth factor and basic fibroblast growth factor)expression of endothelial progenitor cells in the hydrogel-loaded group were higher than those in the hydrogel-unloaded group(P<0.05).(2)In vivo experiment:Hematoxylin-eosin staining and Masson staining showed that at 3 weeks after operation,only a small amount of new bone was found in the two groups,and the material was partially degraded.At 6 weeks after operation,the amount of new bone in the two groups increased,and a large amount of new bone was found in the experimental group,with obvious calcium deposition.At 9 weeks after operation,compared with the control group,a large number of bone trabeculae thicker than mature were found in the experimental group,calcium salt deposition was more obvious,and a large number of osteoblasts were found around the bone trabeculae.The protein expressions of CD31,vascular endothelial growth factor,basic fibroblast growth factor,bone morphogenetic protein 2,type I collagen and osteocalcin in the experimental group were higher than those in the control group at 9 weeks after operation(P<0.05).(3)The exosome-loaded gluconolactone-sodium alginate β-tricalcium phosphate-polyethylene glycol hydrogel could promote the proliferation,migration and angiogenic differentiation of endothelial progenitor cells and promote the repair and regeneration of bone defects around implants.

Research progress on ubiquitin-specific proteases in regulation of bone remodeling / 口腔疾病防治

@#Maintaining bone homeostasis relies on the balance between bone remodeling involving bone resorption by osteoclasts and bone formation by osteoblasts under physiological conditions. An increasing number of studies have shown that the ubiquitin-proteasome system plays an important role in bone remodeling. The ubiquitination process is reversible through the action of deubiquitinase (DUB), and ubiquitin-specific proteases (USPs) are the largest of the DUB families. This article summarizes the mechanisms by which USPs regulate bone homeostasis, including USP4 and USP7, by affecting bone formation through signaling pathways such as Wnt/β-catenin and cylindromatosis (CYLD) and regulating bone resorption through signaling pathways such as nuclear factor-kappa B (NF-κB). In addition to affecting bone resorption and bone formation during bone reconstruction, the effect of USPs on bone is also reflected in the osteogenic differentiation of human periodontal membrane stem cells and implant bone binding. Future research should determine whether USPs have a greater regulatory effect on bone reconstruction and the specific mechanism of their regulatory effect to provide more approaches for the treatment of bone diseases.

Estabilidad y nivel óseo periimplantario de implantes postextractivos en pacientes de la tercera edad / Stability and peri-implant bone level of post-extractive implants in elderly patients

Introducción: Los implantes postextractivos acortan el tiempo en lograr la rehabilitación del paciente, resulta esta condicionante un factor esencial para devolver la calidad de vida en corto plazo a un adulto mayor y mejorar rápidamente su función masticatoria. Objetivo: Determinar los valores de estabilidad y la pérdida ósea periimplantaria en implantes postextractivos en pacientes de la tercera edad. Material y Método: Se realizó un estudio cuasi-experimental en 99 pacientes de la tercera edad en la Facultad de Estomatología ¨Raúl González Sánchez¨, 2017-2019. Bajo su consentimiento se colocaron 173 implantes postextractivos. Se determinó tipo de hueso de soporte, estabilidad primaria y secundaria según análisis de frecuencia de resonancia con Osstel Mentor. Se midió el nivel óseo periimplantario y la pérdida ósea hasta 12 meses de colocada la rehabilitación. Resultados: Se posicionaron mayoritariamente implantes en el sitio de implantación incisivo maxilar en 43,3 por ciento de los casos. Los valores promedio de estabilidad primaria y secundaria fueron 48 ISQ y 68 ISQ respectivamente. La pérdida ósea promedio tras un año de rehabilitación fue de 1,04±0,22mm. Conclusiones: Los implantes dentales postextractivos en pacientes de la tercera edad se insertaron preferentemente en el grupo incisivo maxilar y en hueso tipo D2, registraron una estabilidad primaria promedio moderada y una estabilidad secundaria promedio substancial. La pérdida ósea vertical periimplantaria exhibió valores semejantes a los implantes en zonas curadas y dentro del valor estandarizado para pérdida ósea periimplantaria para el primer año tras su colocación(AU)

Introduction: Post-extractive implants shorten the time in achieving the rehabilitation of the patient, being this condition an essential factor to restore the quality of life to elderly patients at short term. Objective: To determine the stability values and peri-implant bone loss in post-extractive implants in elderly patients. Material and Method: A cohort study was carried out in 99 elderly patients at Raúl González Sánchez Dental School of Havana from 2017 to 2019. Under the consent of the patients, 173 post-extractive implants were placed. Bone support type, and primary and secondary stability were determined on the basis of a resonance frequency analysis with Ostell Mentor®. The peri-implant bone level and peri-implant bone loss were measured until 12 months after rehabilitation. Results: Implants were mainly positioned in the maxillary incisive site in 43,3 percent of the cases. The average values of primary and secondary stability were 48 ISQ and 68 ISQ, respectively. The average bone loss after 12 months of rehabilitation was 1,04 ± 0,22 mm. Conclusions: Post-extractive dental implants were inserted preferably in the maxillary incisive site and in D2 bone type, registering moderated average values of primary stability and substantial average values of secondary stability. The peri-implant vertical bone loss exhibited implants with similar values than those in the healed areas and within the standardized value for peri-implant bone loss within the first year after implant placement(AU)

The influence of bone graft procedures on primary stability and bone change of implants placed in fresh extraction sockets / 대한악안면성형재건외과학회지

BACKGROUND: This study was to evaluate the effect of bone graft procedure on the primary stability of implants installed in fresh sockets and assess the vertical alteration of peri-implant bone radiographically. METHODS: Twenty-three implants were inserted in 18 patients immediately after tooth extraction. The horizontal gap between the implant and bony walls of the extraction socket was grafted with xenografts. The implant stability before and after graft procedure was measured by Osstell Mentor as implant stability quotient before bone graft (ISQ bbg) and implant stability quotient after bone graft (ISQ abg). Peri-apical radiographs were taken to measure peri-implant bone change immediately after implant surgery and 12 months after implant placement. Data were analyzed by independent t test; the relationships between stability parameters (insertion torque value (ITV), ISQ abg, and ISQ bbg) and peri-implant bone changes were analyzed according to Pearson correlation coefficients. RESULTS: The increase of ISQ in low primary stability group (LPSG) was 6.87 ± 3.62, which was significantly higher than the increase in high primary stability group (HPSG). A significant correlation between ITV and ISQ bbg (R = 0.606, P = 0.002) was found; however, age and peri-implant bone change were not found significantly related to implant stability parameters. It was presented that there were no significant peri-implant bone changes at 1 year after bone graft surgery. CONCLUSIONS: Bone graft procedure is beneficial for increasing the primary stability of immediately placed implants, especially when the ISQ of implants is below 65 and that bone grafts have some effects on peri-implant bone maintenance.

COLOCACIÓN DE IMPLANTE DENTAL CON RELLENO ÓSEO BIOGRAFT-G® EN HUESO CON TRAUMA DENTOALVEOLAR. REPORTE DE CASO / PLACEMENT OF DENTAL IMPLANTS WITH OSSEOUS FILLER (BIOGRAFT-G®) IN BONE WITH DENTAL ALVEOLAR TRAUMA. CASE REPORT

En la actualidad, para el odontólogo resulta un gran desafío poder restaurar la apariencia natural y la anatomía de dientes perdidos. En este trabajo se realiza el reporte de un caso clínico donde se restituye el incisivo central superior derecho, a causa de traumatismo dentomaxilofacial, por un implante Leader® combinado con el relleno óseo Biograft-G®. Se trata de una paciente de 19 años atendida en la consulta multidisciplinaria del Centro Nacional de Estomatología, La Habana, Cuba. La paciente portaba prótesis inmediata a causa de la pérdida del diente 11 por fractura de corona y raíz, con defecto óseo vestibular. A la paciente le ocurría fractura frecuente de la prótesis, viéndose afectada desde el punto de vista estético, social, psicoafectivo y funcional. Después de una evaluación multidisciplinaria y el consentimiento de la paciente, se procedió a la cirugía mediante la técnica de colgajo, colocación de implante Leader® y relleno con Biograft-G® para regenerar el defecto óseo, devolver contorno vestibular y lograr una rehabilitación definitiva. Con este tratamiento, la paciente obtuvo los resultados estéticos y funcionales deseados.

Today is a challenge to restore the natural appearance and anatomy of extracted teeth. In this paper we present a clinical case in which the right upper central incisor is restored, due to the presence of a dentomaxillofacial trauma, through a Leader® implant combined with Biograft-G® bone filler. The patient is a 19 year woman treated in the multidisciplinary consultation of the National Center of Stomatology, Havana, Cuba. The patient had an immediate prosthesis due to a fracture of the crown and root, with vestibular bone defect. The patient frequently fractured the prosthesis, which affected her in terms of aesthetics, social, psychological and functional incorporation. After a multidisciplinary evaluation and the patient's consent, the surgery was performed using the flap technique, the placement of the Leader® implant and the filling with Biograft-G® to regenerate the bone defect, to recover the vestibular contour and to achieve a definitive rehabilitation. With this treatment, the patient obtained the desired aesthetic and functional results.

Evaluation of implant-bone contact interface on active zinc coated implants / 国际生物医学工程杂志

Objective To evaluate the implant-bone interfaces on implants with active Zn coating in a rabbit model.Methods Pure titanium cylinder implants,fabricated by machining,were prepared by surface microarc oxidation (MAO).The MAO-Zn/Ca/P coated (experimental group) and the MAO-Ca/P coated (control group)implants were randomly placed in the rabbit mandible.The samples were harvested at 4 and 12 weeks postoperatively,histological analysis on the implant-bone interfaces of the two implants was performed,and the bone coverage was compared.Results The coatings of MAO presented micro-porous structure with dense and uniform features,in which size of micro-porous increased with zinc element.The histological examination of implant-bone contact interfaces showed that the bone tissues attached on the coatings increased with time.Further,the adhered bone tissue in the experimental group was thicker and denser and had a larger amount compared to that in the control group at 4 and 12 weeks postoperatively.The bone coverage in the experimental group (70.8％±13.6％) at 12 weeks postoperatively was significantly higher than that in the control group (55.9％±13.8％) (P＜0.05).The results of bone interface element showed that the apatite layer was precipitated at 12 weeks.Conclusion The addition of active zinc element can improve the biological activity of the coating,enhance the osteogenesis ability of the coating,and accelerate the osseointegration of implant-bone interfaces.

The Success Rate of Implants Placed in Reconstructed Alveolar Ridges Using Iliac Bone Graft Compared to Non-augmented Jaw.

Aim: This study is aimed to investigate the success rate and clinical outcome of placed implants in reconstructed alveolar ridges using iliac cortico-cancellus bone graft compared to normal nonaugmented alveolar ridge. Materials and Methods: In this clinical trial study, 30 patients who were selected and assigned in case and control groups. The case group included patients with severe alveolar bone loss, who needed bone grafting. The control group included patients with sufficient alveolar ridge and no need for bone grafting. The prosthesis was placed on implants after 3 to 8 months. Plaque index, bleeding, pocket depth, mobility, pain, pus secretion and bone loss were evaluated after 24 month. Data were analyzed by SPSS 13. P-value less than 0.05 was considered as significant. Results: Out of 30 patients, two were excluded due to their requirements. Totally 97 implants were placed in patients, which included 52 implants in control group and 45 implants in case group. All of the implants were successfully osseointegrated and loaded. There was no significant difference between the success of inserted implants between both groups (P=0.05). The mesial and distal bone losses were significantly more in patients without iliac bone graft (P=0.05). There was no statistically significant difference between measured outcomes including plaque, bleeding, pocket depth, mobility, pain, and pus secretion (P=0.05). Conclusion: Inserted implant in free non-vascularized iliac bone graft has high rate of success comapred to non-augmented alveolar ridges and has shown to be a reliable method for reconstruction of severe atrophic jaws.

Oral Implant Imaging: A Review

Selecting an appropriate implant imaging technique has become a challenging task since the advent of advanced imaging modalities, and many of these are used for implant imaging. On imaging, the modality should not only consider the anatomy but should also provide dimensional accuracy. Many dentists use the conventional method, mostly orthopantograph (OPG), in their routine practice of implant placement. However, because of the drawbacks associated with OPG, higher technologies, such as computed tomography (CT) and cone beam computed tomography (CBCT), are better accepted. These help improve image sharpness and reduce distortion. These techniques are not used widely due to the cost effect. Therefore, to decide on the type of imaging technique, all associated advantages and disadvantages should be considered, which will be broadly discussed in this review.

Reconstrução imediata de fenestração peri-implantar por meio de enxerto autógeno em bloco obtido do ramo mandibular / Immediate reconstruction of peri-implant fenestration with autogenous block grafts harvested from mandibular ramus

As fenestrações das paredes alveolares são relativamente comuns durante o procedimento cirúrgico para instalação de implantes. O objetivo do presente trabalho foi relatar um caso clínico de reconstrução de fenestração peri-implantar imediatamente após a instalação de implante osseointegrável, através de enxerto ósseo autógeno em bloco obtido do ramo mandibular. Paciente do sexo masculino procurou o Departamento de Cirurgia e Clínica Integrada para trocar sua prótese parcial removível classe IV de Kennedy por prótese parcial fixa implantossuportada. Foram instalados dois implantes nos espaços protéticos correspondente aos dentes 12 e 21. Houve uma fenestração peri-implantar da parede vestibular durante a instalação do implante correspondente ao dente 12, que foi reconstruídapor meio de enxerto autógeno em bloco obtido do ramo mandibular e fixado por meio de parafuso bicortical. Após seis meses de concomitante período de incorporação do enxerto ósseo autógeno e osseointegração, iniciou-se o processamento para confecção da prótese parcial fixa implantossuportada. Diante da reabilitação protética alcançada, concluiu-se que o enxerto ósseo autógeno obtido da área doadora ramo mandibular constitui uma alternativa segura e eficaz para reconstrução de defeitos peri-implantares em forma de fenestração óssea...

Alveolar wall fenestrations are common during implant placement. The aim of this paper is to report a case where a peri-implant bone fenestration was reconstructed immediately after implant placement by an autogenous mandibular bone block. A male patient was referred to the Department of Surgical and Integrated Clinics to substitute his Kennedy´s Class IV removable partial denture for an implantsupported fixed prosthesis. A peri-implant bone fenestration at the buccal wall was seen at the region of 12, being reconstructed by a mandibular bone block secured by a bicortical screw. Six months later the surgical procedures, an implant-supported complete fixed partial prosthesis was developed. The autogenous bone block harvested from the mandibular ramus was a safe alternative to reconstruct the peri-implant bone defect such as fenestration types...

Tomografia computadorizada por feixe cônico para identificação de defeitos ósseos peri-implantares quimicamente simulados em costelas bovinas frescas / Cone beam computed tomography for identification of peri-implant bone loss chemically simulated in fresh bovine ribs

O objetivo deste estudo foi avaliar a acurácia, sensibilidade, especificidade e concordância inter e intra-observador dos exames radiográficos: radiografia periapical digital indireta (RP) por meio de placas de fósforo e tomografia computadorizada por feixe cônico (TCFC) na detecção de defeitos ósseos peri-implantares quimicamente simulados com Ácido Perclórico a 70%. 80 implantes foram instalados em blocos de costela bovina. Os implantes foram divididos em 2 grupos (grupo controle e grupo teste), em seguida o grupo teste foi dividido em 2 subgrupos (G1 e G2). O grupo G1 foi exposto a 4h de ácido causando defeitos de aproximadamente 3-4 mm de profundidade e largura <=1 mm, enquanto o grupo G2 foi exposto a 12h . Posteriormente, as amostras foram submetidas a um sistema de Radiografia digital indireta por meio de placa de fósforo (CS 7600) e a dois diferentes tomógrafos, utilizando variados protocolos (iCAT Next Generation e 3D Accuitomo 170). Os observadores avaliaram as imagens em um programa de visualização independente (OsiriX MD) utilizando a ferramenta a 3D-RMP que permite explorar cortes axiais, coronais, sagitais, parassagitais e circunferenciais simultaneamente. Nas amostras avaliadas por radiografia periapical, os valores da ASC encontrados nas amostras com defeitos ósseo menores variaram entre 0,442 a 0,534; no iCAT Next Generantion, variaram entre 0,645 a 0.828 em dois protocolos diferente. No 3D Accuitomo 170, variaram entre 0.563 a 0.904, em protocolos diferentes. No grupo com defeito ósseos maiores os resultados foram superiores. Na radiografia periapical, os valores encontrados variaram entre 0,652 a 0,771; no iCAT Next Generation, variaram entre 0,708 a 0,946 em dois protocolos diferentes e no 3D Accuitomo 170, entre 0.628 a 0.962 em 4 protocolos diferentes...

The aim of this study was to test the accuracy, sensitivity, specificity, inter and intra-observer and area AZ values of two radiographic examinations: digital periapical radiographs and cone beam computed tomography (CBCT) in the detection of two sizes of peri-implant bone defects chemically simulated with Perchloric Acid 70%. PR and CBCT were performed in 80 dental implants installed in blocks of bovine rib. An indirect digital radiography system using smart phosphor plates (CS 7600) and two different CBCT scanners, using different protocols (iCAT Next Generation 3D Accuitomo 170) were evaluated. Observers evaluated the images in a separate DICOM viewer (OsiriX MD) using the 3D-RMP tool. This tool allows the visualization of axial, coronal, sagittal, cross-section and circumferential images. In samples evaluated by periapical radiography, the AZ values found in the samples with smaller bone defects ranged from 0.442 to 0.534; in iCAT Next Generantion, ranged from 0.645 to 0.828 in two different protocols. In the group with larger bone defect results were superior. In periapical, the values found ranged from 0.652 to 0.771; iCAT the Next Generation ranged from 0.708 to 0.946 in two different protocols and 3D Accuitomo 170, 0.628-0.962 in 4 different protocols...

Pesquisa a serviço da sociedade: área de concentração de Implantodontia do PPGO/UFSC / Scientific research for social benefits: oral Implantology at the PPGO/UFSC

Este manuscrito descreve as atividades desenvolvidas na PPGO/UFSC, concentradas em três linhas de pesquisa: 1) neoformação óssea peri-implantar; 2) engenharia tecidual; e 3) microbiologia aplicada à Implantodontia. Na linha um, diversos métodos analíticos quantitativos e qualitativos (SEM, AFM, FTIR, OCP, EIS, FEG-SEM) têm sido usados para investigação de diferentes intensidades de corrente elétrica na superfície do Ti-cp e Ti-6Al-4V, quando imersos em meios fisiológicos simulados, na adsorção de proteínas, proliferação celular com fibroblastos, queratinócitos e osteoblastos. Na linha dois, o desenvolvimento in vitro de um arcabouço poroso de PLGA e cerâmica bifásica, incorporado com sinvastatina, sera testado in vivo na resposta de fibroblastos gengivais provenientes de cultura primaria, em meio de cultura com plasma rico em plaquetas (PRP), depositado sobre matriz dérmica acelular e matriz de celulose bacteriana (BC). A linha três concentra a atuação com dois centros internacionais (Belgica e EUA) para a incorporação de compostos antibiofilme em polímeros biocompatíveis, e verificação da eficiência de um método de liberação prolongada de antibióticos incorporados em superfícies nanoestruturadas. Estes projetos devem resultar em melhoria de saúde aos pacientes e no desenvolvimento econômico e social da comunidade.

This paper describes the activities developed at PPGO/UFSC divided into three research lines: 1) peri-implant bone neoformation; 2) tissue engineering, and 3) microbiology applied to implant dentistry. On the first line, several quantitative and qualitative (SEM, AFM, FTIR, OCP, EIS, FEG-SEM) analytical methods have been used to investigate the different electric current intensities on Ti c.p. and Ti6Al4V implant surfaces when immersed into simulated physiological media, protein adsorption, cell proliferation with fibroblasts, keratinocytes, and osteoblasts. On the second line, the in vitro development of a 3D PLGA and biphasic ceramic, simvastatin-incorporated scaffold will be tested in vivo for gingival fibroblast response from primary culture in platelet-rich plasma (PRP) enriched vehicle over an acellular dermal (Sure- Derm) and bacterial cellulose matrix (BC). For line three, two international research centers (Belgium and USA) joined common efforts to incorporate polymer anti-biofi lm compounds and to verify the efficiency of a prolonged release method for antibiotics attached to nanostructured surfaces. All those projects must result in better health conditions and social and economic development of our community.

Study of heat transfer to the implant-bone interface induced by grinding of occlusal surface of implant gold prosthesis / 대한치과보철학회지

PURPOSE: The purpose of this study was to analyze temperature change along the implant-bone interface induced by grinding the occlusal surface of implant gold prosthesis and to compare the temperature generated by grinding of prosthesis with different cooling methods. MATERIALS AND METHODS: The experimental gold prostheses were fabricated with dental gold alloy and castable abutment. The prostheses had 3 cylindrical protrusions on the occlusal surface with 1mm in height. Temperature was measured using 16 thermocouple wires attached to the implant fixture surface and the fixture was embedded in an acrylic resin block inside the 37degrees C water bath. Cylinders were grinded for a period of 30 second with a low-speed handpiece with green stone point. One cylindrical protrusion was grinded without cooling, the second one was grinded with air blow, and the third one was grinded with water-spray. RESULTS: The mean maximum temperature was measured more than 47degrees C of the implant and the maximum temperature was measured at the cervical portion of the implant in the group without cooling. There was statistically significant difference between the group without cooling and the groups with cooling (P.05). CONCLUSION: The results of this study support that the grinding of implant gold prosthesis without cooling may damage the peri-implant tissue. The continuous use of air blow and water-spray adjacent to prosthesis during the grinding of implant gold prosthesis may prove to be beneficial for cooling of the implant.

Evaluación clínico-radiográfica del éxito y supervivencia de implantes dentales con tratamiento de superficie e implantes con superficie torneada / Clinical-radiographic success and survival with implants dental surface treatment and surface turned

El objetivo principal del estudio fue evaluar la influencia del tratamiento de superficie del implante en el éxito y supervivencia de estos. Se evaluaron 24 pacientes que presentaban un total de 74 implantes dentales oseointegrados, 19 con superficie torneada y 55 superficie RBM® (Lifecore® Biomedical, Chaska, Minn). Los resultados obtenidos fueron una tasa de supervivencia de 98.18% para los implantes de superficie RBM®, 100% para los de superficie lisa y para el total de implantes 98.65%. La tasa de éxito para los implantes de superficie lisa fue 63.16%, para los de superficie RBM® 70.91% y para el total de implantes 68.92%; sin encontrar diferencias estadísticamente significativas entre estas. La pérdida ósea fue 1.82mm para los implantes de superficie torneada y 1.34mm para los de superficie RBM®, encontrándose esta diferencia estadísticamente significativa. Los resultados obtenidos indican que los implantes con superficie RBM® a comparación de los implantes con superficie torneada, presentan ventajas con respecto a la pérdida ósea marginal. También se observó que la variable que mayor influencia ejerce sobre la pérdida ósea marginal y el éxito del implante es el momento de la carga.

The principal aim of our study was to evaluate the survival and success rate of implants with treated surface (RBM®) and machined surface implants. 24 patients treated with 74 dental implants were evaluated. 19 machined surface implants and 55 RBM® surface implants (Lifecore® Biomedical, Chaska, Minn). The results were a survival rate of 98.18 % for RBM® implants, 100% for machined or smooth surface and 98.65 % and for the whole of implants. The success rate for smooth implants was 63.16% for RBM® implants was 70.91% and for the whole of implants was 68.92%. These results were not significantly different. However, peri-implant bone loss was significantly different between smooth implants (1.82mm) and RBM® implants 1.34. The results indicate that implants RBM present advantages with regard to the marginal bone loss. Also was observed that the load time is the variable that major influence has on the marginal bone loss and the implant success.

Finite element analysis of peri-implant bone stresses induced by root contact of orthodontic microimplant / 대한치과교정학회지

OBJECTIVE: The aim of this study was to evaluate the biomechanical aspects of peri-implant bone upon root contact of orthodontic microimplant. METHODS: Axisymmetric finite element modeling scheme was used to analyze the compressive strength of the orthodontic microimplant (Absoanchor SH1312-7, Dentos Inc., Daegu, Korea) placed into inter-radicular bone covered by 1 mm thick cortical bone, with its apical tip contacting adjacent root surface. A stepwise analysis technique was adopted to simulate the response of peri-implant bone. Areas of the bone that were subject to higher stresses than the maximum compressive strength (in case of cancellous bone) or threshold stress of 54.8MPa, which was assumed to impair the physiological remodeling of cortical bone, were removed from the FE mesh in a stepwise manner. For comparison, a control model was analyzed which simulated normal orthodontic force of 5 N at the head of the microimplant. RESULTS: Stresses in cancellous bone were high enough to cause mechanical failure across its entire thickness. Stresses in cortical bone were more likely to cause resorptive bone remodeling than mechanical failure. The overloaded zone, initially located at the lower part of cortical plate, proliferated upward in a positive feedback mode, unaffected by stress redistribution, until the whole thickness was engaged. CONCLUSIONS: Stresses induced around a microimplant by root contact may lead to a irreversible loss of microimplant stability.

Avaliação da resistência a tração de diferentes enxertos em calvária de ratos / Evaluation of the tensile strength of different grafts in rat calvaria

A perda do osso alveolar como resultado de doença periodontal ou secundariamente à cirurgia são fontes de inúmeras complicações para os cirurgiões dentistas, e a solução para tal problema se baseiam em procedimentos regenerativos, que é realizada através de enxertos ósseos que estabelecem um arcabouço para a reparação tecidual, aumentando os tecidos ósseos nos defeitos resultantes de trauma ou cirurgias, preenchendo os alvéolos após extração para preservar a altura e espessura do rebordo alveolar e aumentando e/ou reconstruindo o rebordo alveolar. Este projeto tem como objetivo determinar a resistência à tração do osso neoformado com a utilização de diferentes biomateriais. Foram utilizados 60 animais divididos em 3 grupos. O grupo 1A (n=10): GenO; Grupo 1B (n=10): GenMix; Grupo1C (n=10): Bio-Oss; Grupo 2a (n=10): PerioGlas; Grupo 2b (n=10): Polímero de mamona e Grupo 3 (n=10): coágulo. Após 3 meses de nascimento os animais foram submetidos a anestesia intraperitonial e confecção de defeito não critico (3mm de diâmetro) na calvária dos animais, que foram preenchidos com os biomateriais correspondentes a cada grupo. Após 6 meses da cirurgia foi realizada a morte dos animais, os espécimes foram coletados e submetidos ao teste em uma máquina de teste universal. Observa-se que o grupo que obteve maior média de resistência à tração foi o grupo de polímero de mamona (10,932±4,529MPa). Consequentemente, obteve-se uma comparação descrescente na seguinte ordem: Coágulo (9,563±3,74MPa), Bio-Oss (8,706±4,087MPa), GenMix (8,587±3,602MPa), GenOx (7,709±2,416MPa), PerioGlas (7,185±6,837MPa), não notando-se diferença estatisticamente significante entre os grupos. Nas microscopias eletrônicas de varredura na maioria dos grupos observou-se presença de fibras colágenas ao redor do tecido ósseo neoformado e dos remanescentes de enxerto. Conclui-se que o material foi indiferente para o resultado final da resistência à tração, demonstrando uma...

The loss of alveolar bone as a result of periodontal disease or secondary to surgery are numerous sources of complications for the dentists, and the solution to this problem are based on regenerative procedures, which is conducted through bone grafts that provide a scaffold for tissue repair by increasing the bone tissues in the defects resulting from trauma or surgery, filling the alveoli after extraction to preserve the height and thickness and increasing the alveolar ridge and/or reconstructing the alveolar ridge. This project aims to determine the tensile strength of newly formed bone with the use of different biomaterials. We used 60 animals divided into three groups. Group 1A (n = 10): GenOx; Group 1B (n = 10): GenMix; Group 1C (n = 10): Bio-Oss; Groups 2a (n = 10): PerioGlas; Group 2b (n = 10): castor bean polymer; Group 3 (n = 10): clot. After 3 months of birth the animals were anesthetized intraperitoneally and making non critical defect (3mm diameter) in the calvaria of the animals, which were filled with biomaterials for each group. After 6 months of surgery was performed the animals' death, the specimens were collected and tested in a universal testing machine. It is observed that the group had a higher average tensile strength was the castor oil polymer group (10.932 ± 4.529 MPa). Consequently, we obtained a comparison descended in the following order: Clot (9.563 ± 3.74 MPa), Bio-Oss (8.706 ± 4.087 MPa), GenMix (8.587 ± 3.602 MPa), GenOx (7.709 ± 2.416 MPa), PerioGlas (7.185 ± 6.837 MPa), not noticing a significant difference between the groups. In scanning electron microscopies in most groups there was presence of collagen fibers around the newly formed bone and remaining graft. It is concluded that the material was irrelevant to the final result of the tensile strength, showing a good quality of materials used, both when comparing products as their source (xenogenic, polymeric or clot), or its origin of manufacture (national or imported).

Avaliação da resistência a tração de diferentes enxertos em calvária de ratos / Evaluation of the tensile strength of different grafts in rat calvaria

A perda do osso alveolar como resultado de doença periodontal ou secundariamente à cirurgia são fontes de inúmeras complicações para os cirurgiões dentistas, e a solução para tal problema se baseiam em procedimentos regenerativos, que é realizada através de enxertos ósseos que estabelecem um arcabouço para a reparação tecidual, aumentando os tecidos ósseos nos defeitos resultantes de trauma ou cirurgias, preenchendo os alvéolos após extração para preservar a altura e espessura do rebordo alveolar e aumentando e/ou reconstruindo o rebordo alveolar. Este projeto tem como objetivo determinar a resistência à tração do osso neoformado com a utilização de diferentes biomateriais. Foram utilizados 60 animais divididos em 3 grupos. O grupo 1A (n=10): GenO; Grupo 1B (n=10): GenMix; Grupo1C (n=10): Bio-Oss; Grupo 2a (n=10): PerioGlas; Grupo 2b (n=10): Polímero de mamona e Grupo 3 (n=10): coágulo. Após 3 meses de nascimento os animais foram submetidos a anestesia intraperitonial e confecção de defeito não critico (3mm de diâmetro) na calvária dos animais, que foram preenchidos com os biomateriais correspondentes a cada grupo. Após 6 meses da cirurgia foi realizada a morte dos animais, os espécimes foram coletados e submetidos ao teste em uma máquina de teste universal. Observa-se que o grupo que obteve maior média de resistência à tração foi o grupo de polímero de mamona (10,932±4,529MPa). Consequentemente, obteve-se uma comparação descrescente na seguinte ordem: Coágulo (9,563±3,74MPa), Bio-Oss (8,706±4,087MPa), GenMix (8,587±3,602MPa), GenOx (7,709±2,416MPa), PerioGlas (7,185±6,837MPa), não notando-se diferença estatisticamente significante entre os grupos. Nas microscopias eletrônicas de varredura na maioria dos grupos observou-se presença de fibras colágenas ao redor do tecido ósseo neoformado e dos remanescentes de enxerto. Conclui-se que o material foi indiferente para o resultado final da resistência à tração, demonstrando uma...

The loss of alveolar bone as a result of periodontal disease or secondary to surgery are numerous sources of complications for the dentists, and the solution to this problem are based on regenerative procedures, which is conducted through bone grafts that provide a scaffold for tissue repair by increasing the bone tissues in the defects resulting from trauma or surgery, filling the alveoli after extraction to preserve the height and thickness and increasing the alveolar ridge and/or reconstructing the alveolar ridge. This project aims to determine the tensile strength of newly formed bone with the use of different biomaterials. We used 60 animals divided into three groups. Group 1A (n = 10): GenOx; Group 1B (n = 10): GenMix; Group 1C (n = 10): Bio-Oss; Groups 2a (n = 10): PerioGlas; Group 2b (n = 10): castor bean polymer; Group 3 (n = 10): clot. After 3 months of birth the animals were anesthetized intraperitoneally and making non critical defect (3mm diameter) in the calvaria of the animals, which were filled with biomaterials for each group. After 6 months of surgery was performed the animals' death, the specimens were collected and tested in a universal testing machine. It is observed that the group had a higher average tensile strength was the castor oil polymer group (10.932 ± 4.529 MPa). Consequently, we obtained a comparison descended in the following order: Clot (9.563 ± 3.74 MPa), Bio-Oss (8.706 ± 4.087 MPa), GenMix (8.587 ± 3.602 MPa), GenOx (7.709 ± 2.416 MPa), PerioGlas (7.185 ± 6.837 MPa), not noticing a significant difference between the groups. In scanning electron microscopies in most groups there was presence of collagen fibers around the newly formed bone and remaining graft. It is concluded that the material was irrelevant to the final result of the tensile strength, showing a good quality of materials used, both when comparing products as their source (xenogenic, polymeric or clot), or its origin of manufacture (national or imported).

Influence of the adjacent periodontium and inter-implant distance on bone resorption around non-submerged implants: A retrospective clinical and radiographic study / 대한치주과학회지

The aims of the present study are firstly to investigate the amount of bone loss around non-submerged implants placed in the posterior region and secondly to investigate the relationship between inter-implant and implant-tooth distance and peri-implant bone loss. Thirty-one subjects with 60 implants were selected consecutively from the implant patient pool at the department of Chonbuk National University Hospital. To be included in the study subject, the implant should have been functioned more than 6 months after loading. Inter-implant and implant-tooth distance, distance between implant shoulder and the first bone contact with the implant(DIB) were measured from the scanning image of the radiograph of each implant. The result showed that; 1. inter-implant distance has a statistically significant relationship with DIB in Pearson correlation analysis. 2. the DIB at the implant facing surface of the implant was greater than that of tooth facing surface of the implant. Within limitation of this study, it is suggested to place an implant not too closely to adjacent implants, and the presence of a tooth adjacent to an implant may keep the level of tooth-facing surface of the implant. Further studies with a prospective design are needed to elucidate the relationship between bone changes and various dimensions around implants.

The effects of different implant diameter on stress distribution in implant-bone interface / 实用口腔医学杂志

Objective:To investigate the effects of different impl an t diameter on stress distribution in implant bone interface. Method: The stress and strain in implant bone interface for implants with di fferent diameter (3.0 mm,3.75 mm and 5.0 mm), and with 1.47 N loading mesiodist ally were analyzed by 3 dimesion finite element analysis method. Re sults:The Von mises stress (MPa)at cervix of the implants with the diameter (mm) of 3.0, 3.75 and 5.0 were 0.807,0.533 and 1.080;the alveolar bone displacement (?m) at the cervix of the implants 0.232,0.163 and,0.111 respe ctively. Conclusion: The implant with 3.75 mm diameter is more suitable for orthodontic anchorage.

Implant-bone interface remodeling of submerged and nonsubmerged implant denture in beagle dogs / 实用口腔医学杂志

Objective: To study the implant-bone interface remodelin g after loading of submerged and nonsubmerged implant denture.Methods: 8 adult beagle dogs were used to build the animal model. Submerged and nons ubmerged implants were implanted into the bilateral mandible. Fixed metal full c rown was used to carry out the submerged and nonsubmerged implant denture. The b eagle dogs were sacrificed by steps after loading of the dentures. HE staining t echnique was used to observe the dynamic remodeling process of implant-bone int erface.Results:2 weeks after loading of implant denture, a major ity of the implant surface attached to bone tissue directly, however, at the int erface, especially at the top of the screw thread, bone tissues were absorbed an d substituted by fibrous tissues. 4 weeks after loading, fine attachment was fou nd at the implant-bone interface and the previouly observed fibrous tissue at t he interface was gradually remodeled to form new bone. 8 weeks after loading, i mplant directly attached to bone tissues by osteo-interface, and the cellular c omponents and capillaries were decreased at the interface.12 weeks after loading , all implants attached to bone tissues by osteo-interface with high combinatio n level, typical Havers system was observed at the interface.No obvious differen ce in the interface remodeling was observed between the submerged and nonsubmerg ed implant denture. Conclusion:There is no distinct difference i n the implant-bone interface remodeling after the loading of submerged and nons ubmerged implant denture.

Evaluation of the Interfaces Between Implants And Regenerated Bone Using Bone Morphogenetic Protein and Demineralized Freeze-dried Bone

Various methods and graft materials have been used to fill in the defect adjacent to the implants and considered as clinically acceptable. But it is not clear whether the regenerated bone increases the implant-bone contact and supports the implant. The purpose of this study is to evaluate regenerated bone surrounding implants using bone morphogenetic protein(BMP) and demineralized freeze-dried bone(DFDB), and the interfaces between implants and regenerated bone. bBMP was extracted and partially purified from the bovine bone matrix using heparine chromatography. Demineralized freeze-dried bone was made from the dog. Inactive insoluble collagenous bone matrix(IBM) of dog was used as carrier of bBMP. Interfaces of titanium coated epoxy resin implants were processed for demineralized section for transmission electron microscopy(TEM) and those of screw type implants were for nondemineralized section for light and fluoromicroscopic examination. Implants were inserted in the inferior border of mandible of adult dogs and artificial bony defects (3x3x4mm) were made at the mesial and distal side of implants. Defects were filled with BMP(BMP group) and DFDB(DFDB group). For the fluoromicroscopic examination, the fluorescent dyes (oxytetracycline, calcein green, alizarin red) were injected 2, 4, 6, 8, 12 weeks after implantation. The experimental animals were sacrificed at the 6th and the 12th week and their mandible were extirpated and processed for examination with light microscopy, fluoromicroscopy and TEM. The obtained results were as follows : 1. By the light microscopic findings, the defects were filled with woven bone at the 6th week and compact bone at the 12th week, and the osseointegrations were seen in both groups. There was no histological difference between them. 2. On the basis of the histomorphometric analysis, BMP group (6th week: 40.25%, 12th week: 56.04%) had higher bony contact ratio than DFDB group (38.37%, 42.63%). There was significant difference between two groups at the 12th week (P<0.05). 3. The amount of bone formation in BMP group was more prominent than in DFDB group. Significant difference was noted among two groups at the 6th and the 8th week (P<0.05). 4. By the transmission electron microscopic findings, 0.4-2micrometer soft tissue layer was found in adjacent to the interfaces and over the collagen fibrils of bone at the 6th week. However, about 100nm amorphous layer was noted at the interface or collagen fibrils directly extended to the titanium surface at the 12th week. There was no significant difference between two groups. 5. These results suggest that BMP and DFDB can be used as good graft materials in the regeneration of bone adjacent to implant, and BMP is more valuable as a bone inducer than DFDB.