Osseointegration and Success in Hip Arthroplasty Acetabular Revision Using Structured Homologous Graft Average 9.6 Years Follow-up / Osteointegração e sucesso em revisão acetabular de artroplastia total de quadril com enxerto estrutural homólogo seguimento médio de 9, 6 anos

Abstract Objective To evaluate the clinical and radiographic results and survival of the acetabular revision surgery of total hip arthroplasty with cemented implant without the use of reinforcement ring, associated with structural homologous bone grafting. Methods A total of 40 patients (44 hips) operated from 1995 to 2015 were retrospectively analyzed. Radiographs were evaluated according to the classification of the acetabular bone defect, graft shape, and the presence of osseointegration. Cases were considered as failures when the migration of the implant was > 5 mm in any direction, and/or the progression of radiolucency lines around the acetabular component were > 2 mm. We verified the association of radiographic findings with cases of failure using statistical tests and analyzed survival using the Kaplan-Meier curve. Results Of the 44 hips, 45.5% of the acetabular defects were Paprosky type 3A and 50% were 3B. In 65% of the hips, the graft configuration was classified as Prieto type 1 and in 31% as type 2. No radiographic evidence of osseointegration was observed in 13.6% of the cases. We observed 9 (20.5%) reconstruction failures. A correlation was observed between reconstruction failure and the absence of radiographic signs of graft osseointegration. Conclusion We observed good clinic and radiographic results, with survival of 79.54% in a mean follow-up of 9.65 years. Also, there was an association between absence of radiographic signs of osseointegration of the structural graft and failure in this series of patients with large bone defects. The failures did not correlate with the severity of the acetabular bone defect, thickness, or graft configuration.

Resumo Objetivo Avaliarosresultadosclínicos, radiográficos e a sobrevida da cirurgia de revisão acetabular de artroplastia total de quadril com implante cimentado sem uso de anel de reforço, associado à enxertia óssea homóloga estrutural. Métodos Um total de 40 pacientes (44 quadris) operados de 1995 a 2015 foram analisados retrospectivamente. As radiografias foram avaliadas de acordo com a classificação do defeito ósseo acetabular, o formato do enxerto e à presença de osteointegração. Foram considerados casos de insucesso a migração do implante > 5 mm em qualquer direção e/ou a progressão de linhas de radioluscência em torno do componente acetabular > 2mm. Verificamos a associação dos achados radiográficos com os casos de falha utilizando testes estatísticos e analisamos a sobrevida utilizando a curva de Kaplan-Meier. Resultados Dos 44 quadris, 45,5% dos defeitos acetabulares eram Paprosky tipo 3A e 50%, 3B. Em 65% dos quadris, a configuração do enxerto foi classificada como tipo 1 de Prieto e em 31% como tipo 2. Não foi observada evidência radiográfica de osteointe-gração em 13,6% dos casos. Observamos 9 (20,5%) falhas de reconstrução. Foi observada correlação entre falha da reconstrução com a ausência de sinais radiográficos de osteointegração do enxerto. Conclusão Observamos bons resultados clínicos e radiográficos, com sobrevida de 79,54% em seguimento médio de 9,65 anos. Também houve associação entre ausência de sinais radiográficos de osteointegração do enxerto estrutural e falha nesta série de pacientes com grandes defeitos ósseos. As falhas não se correlacionaram com a severidade do defeito ósseo acetabular, espessura ou configuraçãodoenxerto.

Midterm Radiographic Results and Reoperations of Tantalum Trabecular Metal Cones in Knee Arthroplasties / Reoperações e resultados radiográficos de médio prazo do uso de cone de metal trabecular de tântalo nas artroplastias do joelho

Abstract Objective The management of bone loss represents a challenge in revisions of total knee arthroplasty (rTKA) and in complex primary total knee arthroplasties (TKAs). The purpose of the present study was to evaluate the midterm outcomes (5-year minimum follow-up) of knee reconstructions with tantalum trabecular metal (TM) cones on bone defects Anderson Orthopaedics Research Institute (AORI) 2 and 3. Materials and MethodsA retrospective analysis of the medical records of patients operated on between July 2008 and November 2014 was performed, collecting the following data: age, gender, laterality, body mass index, etiology of arthrosis, comorbidities, AORI classification of bone defects, causes for revision, readmissions, reoperations, perioperative and postoperative complications, radiographic signs of osteointegration, and maintenance of the TM support. Results A total of 11 patients with a mean follow-up of 7.28 years (standard deviation [SD] = 1.88; range = 5.12-10 years) was evaluated, with 1 patient operated upon for a primary arthroplasty, 6 for revision arthroplasties, and 4 for a second revision arthroplasty (re-revision). There were complications with the surgical wound, injury to the extensor mechanism and loosening of the femoral component in three of the patients that led to the necessity of four procedures due to complications with the surgical wound, injury to the extensor mechanism and loosening of the femoral component. Radiological signs of osteointegration of the trabecular cones were observed in all patients. We did not observe migration of the TM cones or the prosthetic components in the sample. Conclusion The tantalum metaphyseal cones were able to provide efficient structural support to prosthetic implants with radiographic signs of osteointegration in the medium term.

Resumo Objetivo O manejo da perda óssea representa um grande desafio em cirurgias de revisão de artroplastia do joelho (rATJ) e em artroplastias totais do joelho (ATJ) primárias complexas. O objetivo do presente estudo foi avaliar os resultados em médio prazo (seguimento mínimo de 5 anos) das reconstruções de joelho nas quais cones de metal trabecular (MT) de tântalo foram utilizados para tratamento de defeitos ósseos tipos 2 e 3, de acordo com a classificação proposta pela Anderson Orthopaedic Research Institute (AORI). Métodos Feita análise retrospectiva dos prontuários dos pacientes operados entre julho de 2008 e novembro de 2014, coletando-se os seguintes dados: idade, gênero, lateralidade, índice de massa corporal, etiologia da artrose, comorbidade, classificação AORI da falha óssea, causa da revisão da artroplastia total do joelho, reinternações, reoperações, complicações peri- e pós-operatórias, ocorrência de osteointegração radiográfica e manutenção da função de suporte do MT. Resultados Foram avaliados 11 pacientes com tempo médio de seguimento de 7,28 anos (desvio padrão [DP] = 1,88; variação = 5,12-10 anos), sendo que 1 paciente foi submetido a artroplastia primária, 6 a artroplastia de revisão e 4 a segunda revisão de artroplastia (re-revisão). Três pacientes necessitaram de quatro reoperações devido a complicações com a ferida operatória, a lesão do mecanismo extensor e a soltura do componente femoral. Sinais de osteointegração dos cones trabeculados foram observados em todos os pacientes. Não observamos migração do cone de MT ou dos componentes protéticos. Conclusão Os cones metafisários de tântalo foram capazes de prover suporte estrutural eficiente aos implantes protéticos com sinais radiográficos de osteointegração em médio prazo.

Integración de tres especialidades estomatológicas en el tratamiento protésico / Integration of three stomatological specialties in the prosthetic treatment

Los implantes dentales son una opción de restauración estética, funcional y armónica, cuya tasa de éxito es superior a 95 %. Se presenta el caso clínico de una paciente de 24 años de edad, atendida en la consulta de Ortodoncia de la Clínica Estomatológica Provincial Docente Mártires del Moncada de Santiago de Cuba, quien fue remitida desde el Servicio de Prótesis Estomatológica, con el fin de lograr el espacio adecuado para colocarle un implante, pues desde los 12 años de edad aproximadamente había perdido un diente a causa de caries. La restauración protésica mediante el implante dental proporcionó un excelente resultado.

Dental implants are an option of cosmetic, functional and harmonic repairs whose rate of success is higher than 95 %. The case report of a 24 years patient is presented. She was assisted in the Orthodontics Service of Mártires del Moncada Teaching Provincial Stomatological Clinic in Santiago de Cuba and was referred from the Stomatological Prosthesis Service, with the purpose of achieving the appropriate space to place an implant, because she had lost a tooth due to dental decay since she was approximately 12 years. The prosthetic repair by means of dental implant provided an excellent result.

Comparative Study of the Osteointegration of Irradiated and Non-irradiated Bone Grafts Used in Patients with Revision Hip Arthroplasty / Estudo comparativo da osteointegração de enxertos ósseos irradiados e não irradiados utilizados em pacientes com revisão de artroplastia do quadril

Abstract Objective To evaluate and compare the osteointegration of irradiated and nonirradiated frozen bone grafts used in 21 patients undergoing revision hip arthroplasty procedures with the Exeter technique. Methods A retrospective study of 21 patients undergoing revision hip arthroplasty with the Exeter technique using bone tissues treated or not with gamma radiation between 2013 and 2014. The patients were divided into two groups according to the use of grafts treated or not with ionizing radiation (gamma rays); as such, these groups were classified as irradiated or non-irradiated. The osteointegration results determined by radiographic analysis of these grafts were compared in the postoperative period of 6 and 12months. Results Comparing the graft osteointegration in all patients at 6 and 12months postoperatively, we noticed a significant difference in the radiographic evaluations in this period (p = 0.031). Out of the patients studied, 7 were from the irradiated group, and 14 belonged to the non-irradiated group. No statistically significant differences were observed (p = 0.804) regarding osteointegration when we compared the irradiated and non-irradiated groups. Conclusion There was no significant difference in the use of irradiated or nonirradiated grafts in revision hip arthroplasty procedures with the Exeter technique.

Resumo Objetivo Avaliar e comparar a osteointegração dos enxertos ósseos congelados irradiados e não irradiados utilizados em 21 pacientes submetidos a revisão de prótese do quadril pela técnica Exeter. Métodos Foi realizado estudo retrospectivo de 21 pacientes submetidos a revisão de artroplastia do quadril pela técnica Exeter comutilização de tecidos ósseos tratados ou não com radiação gama no período entre 2013 e 2014. Dividimos os pacientes em dois grupos, de acordo com o uso do enxerto tratado ou não com radiação ionizante (raios gama), que foram, portanto, classificados como: grupo irradiado e não irradiado. Os resultados da osteointegração por análise radiográfica destes enxertos foram comparados no pós-cirúrgico de 6 e 12 meses. Resultados Quando comparamos a osteointegração dos enxertos no pós-cirúrgico de 6 e 12 meses de todos os pacientes, notamos que houve diferença significativa entre as avaliações radiográficas neste período (p= 0,031). Dos pacientes estudados, 7 pertenciam ao grupo irradiado, e 14, ao grupo não irradiado. Não foram observadas diferenças estatisticamente significativas (p= 0,804) quando a osteointegração entre os grupos irradiados e não irradiados foi comparada. Conclusão Não houve diferença significativa no uso de enxerto irradiado e não irradiado nas revisões de artroplastias do quadril pela técnica Exeter.

MicroRNA-29a-3p regulates osteoblast differentiation and peri-implant osseointegration in a rat model of hyperlipidemia by modulating Frizzled 4 expression / 华西口腔医学杂志

OBJECTIVE@#This work aimed to study and identify the influence and target gene of microRNA-29a-3p (miR-29a-3p) in the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) in a high-fat environment in vitro and in vivo.@*METHODS@#1) In vitro: BMSCs were randomly allocated into two groups and were then induced to undergo osteogenic differentiation in a normal or high-fat environment. Next, a miR-29a-3p mimic/inhibitor was transfected into the two groups of cells. The mRNA expression levels of alkaline phosphatase (ALP), Runt related gene 2 (Runx2), and miR-29a-3p and the protein expression levels of ALP and Runx2 were detected before and after transfection through reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) and Western blot analyses. Moreover, Frizzled (Fzd) 4 was predicted as the target gene of miR-29a-3p by using an online database (Target Scan, MiRNA.org). The interactive relationship between miR-29a-3p and Fzd4 was confirmed through dual-luciferase assays. 2) In vivo: Rats were randomly divided into two groups and fed with a standard or high-fat diet. Titanium implants were grown in rats. Then, the expression levels of miR-29a-3p, ALP, and Runx2 were detected in bone tissues surrounding implants. Moreover, hard tissue sections were subjected to methylene blue-acid magenta staining and observed under microscopy to study bone formation around implants. In addition, miR-29a-3p-overexpressing lentiviral vectors were transfected into rats, and the expression levels of ALP, Runx2, and miR-29a-3p in bone tissues surrounding implants were detected at 3 and 10 days after transfection.@*RESULTS@#The expression levels of ALP, Runx2, and miR-29a-3p and the osteogenic differentiation of BMSCs were suppressed in high-fat groups in vitro and in vivo.@*CONCLUSIONS@#MiR-29a-3p plays a positive role in the regulation of BMSCs in a high-fat environment. It can increase ALP and Runx2 expression levels in bone tissues surrounding implants in hyperlipidemia models. This result implies that miR-29a-3p can promote implant osseointergration in a rat model of hyperlipidemia.

Research progress of porous tantalum in bone tissue engineering / 中国修复重建外科杂志

Objective : To review the basical research progress of porous tantalum in bone tissue engineering. Methods: The related basical research in fabrication, cytobiology, and surface modification of porous tantalum was reviewed and analyzed. Results: The outstanding physiochemical properties of porous tantalum granted its excellent performance in biocompatibility and osteointegration, as well as promoting cartilage and tendon tissue restoration. However, the clinical utilization of porous tantalum is somehow greatly limited by the complex and rigid commercial fabrication methods and extraordinary high cost. Along with the publication of novel fabrication and surface modification technology, the application of porous tantalum will be more extensive, the promotion in bone tissue regeneration will be more prominent. Conclusion: Porous tantalum has advantage in bone defect restoration, and significant breakthrough technology is needed in fabrication methods and surface modification.

Aspecto morfológico da interface entre o compósito, constituído de quitosana e polimetilmetacrilato, e a falha óssea de tíbia de coelhos / Morphological aspect of the interface between the composite, made of chitosan and polymethylmethacrylate, and bone failure of the rabbit tibia

As afecções ortopédicas com perda de tecido ósseo são um desafio não só na medicina veterinária mas também na medicina humana. Analisou a interface entre compósito, constituído de esferas de quitosana e polimetilmetacrilato em falha óssea (leito receptor) de tíbia de coelhos, por meio de técnica radiológica, avaliação macroscópica e pela microscopia eletrônica de varredura, em diferentes tempos. Foram utilizados 12 coelhos adultos da raça Nova Zelândia, divididos em quatro Grupos Experimentais (E1, n=3; E2, n=3; E3, n=3 e E4, n=3), que tiveram as falhas ósseas das tibiais direitas preenchidas com compósito, e avaliadas no pós-operatório imediato, aos 30, 60 e 90 e 120 dias. Dos compósitos implantados nas tíbias de coelhos, apenas dois permaneceram em seus leitos receptores, enquanto que os demais se encontravam encapsulados no tecido subcutâneo. As esferas de quitosana, presentes nas superfícies dos biomateriais implantados, que mantiveram contato direto com o leito receptor de tíbias de coelhos apresentavam-se preservadas e não integraram ao tecido ósseo. Diante disso, para melhor compreensão do comportamento da quitosana como substituto ósseo, novas pesquisas serão necessárias.(AU)

Orthopedic diseases with bone loss are challenging in both veterinary and human medicine. The aim of this investigation was to analyze and compare the reactions at the interface between the composite, made of chitosan and polymethylmethacrylate, and the bone defect (receptor site) of the rabbits tibia through radiological and microscopic techniques and by scanning electron microscopy, in different periods. Twelve adult New Zealand rabbits were divided into four experimental groups (E1, n=3; E2, n=3; E3, n=3 and E4, n=3), which had the right tibial bone defects filled with the composite, and evaluated in the immediate postoperative, 30, 60, 90 and 120 days. Composite implanted in the tibia of rabbits, only two remained in their beds receivers, while the remaining were encapsulated in the subcutaneous tissue. Spheres of chitosan present in the biomaterial that has been deployed and were in direct contact with the bone defect, were preserved, however, were not integrated into the bone tissue. Therefore, to understand the behavior of chitosan as a bone substitute, further research is needed.(AU)

Osteointegration of porous absorbable bone substitutes: A systematic review of the literature

Biomaterials' structural characteristics and the addition of osteoinductors influence the osteointegration capacity of bone substitutes. This study aims to identify the characteristics of porous and resorbable bone substitutes that influence new bone formation. An Internet search for studies reporting new bone formation rates in bone defects filled with porous and resorbable substitutes was performed in duplicate using the PubMed, Web of Science, Scielo, and University of São Paulo Digital Library databases. Metaphyseal or calvarial bone defects 4 to 10 mm in diameter from various animal models were selected. New bone formation rates were collected from the histomorphometry or micro-CT data. The following variables were analyzed: animal model, bone region, defect diameter, follow-up time after implantation, basic substitute material, osteoinductor addition, pore size and porosity. Of 3,266 initially identified articles, 15 articles describing 32 experimental groups met the inclusion criteria. There were no differences between the groups in the experimental model characteristics, except for the follow-up time, which showed a very weak to moderate correlation with the rate of new bone formation. In terms of the biomaterial and structural characteristics, only porosity showed a significant influence on the rate of new bone formation. Higher porosity is related to higher new bone formation rates. The influence of other characteristics could not be identified, possibly due to the large variety of experimental models and methodologies used to estimate new bone formation rates. We suggest the inclusion of standard control groups in future experimental studies to compare biomaterials.

Effects of high glucose on osteogenic differentiation of hBMSC / 口腔疾病防治

Objective@# To investigate the effects of different glucose concentration on the proliferation and osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSC) in vivo@*Methods@#Cultured with basal medium containing different glucose concentrations, CCK-8 cell proliferation was detected at 1, 4, 7, 10 days. The osteogenic differentiation of human bone marrow mesenchymal stem cells was observed at 7 d, which was induced by osteogenic differentiation medium with different concentration of glucose. The expressions of alkaline phosphatase (ALP), osteocalcin (OC) and collagen type I (Col-1) gene were detected by real-time fluorescence quantitative PCR. Mineralized nodule formation was displayed by calciumalizarin red staining on the seventh day.@*Results @#10 mM glucose stimulated proliferation of hBMSC, while the higher (>30 mM) inhibited the proliferation (P < 0.05); Osteogenic induction can induce osteogenic differentiation of hBMSC, but the increase of glucose concentration will decrease the formation of mineralized nodules of hBMSC, inhibit the expression of osteogenic marker genes ALP, OC and Col-1 (P < 0.05).@*Conclusion@#The expression of Col-1, ALP and OC in osteoblast was down-regulated by high glucose, and the hBMSC proliferation was inhibited. At the same time, high glucose can reduce the osteogenic mineralization ability of stem cells and indirectly affect bone formation and metabolism.

Principales factores causales del fracaso de los implantes dentale / Main factors provoquing dental implant failure

Se realizó un estudio descriptivo y transversal de 97 pacientes que asistieron al Servicio de prótesis de la Clínica Estomatológica Provincial Docente "Mártires del Moncada" de Santiago de Cuba desde septiembre de 2013 hasta igual mes de 2014, para identificar los principales factores causales del fracaso de los implantes dentales en ellos. Entre las variables analizadas figuraron: sexo, edad, tipo de prótesis y otras; entre las principales causas del fracaso sobresalieron la ausencia de osteointegración en el maxilar superior y los sectores posteriores en ambas arcadas, así como la pérdida de esa osteointegración en el puente fijo.

A descriptive and cross-sectional study of 97 patients that attended the Prosthesis Service of "Mártires del Moncada" Teaching Provincial Stomatological Clinic in Santiago de Cuba was carried out from September, 2013 to the same month in 2014, to identify the main factors provoquing dental implant failure. Among the analyzed variables we can mention: sex, age, prosthesis type and others; among the main causes of the failure there were: absence of osteointegration in the maxilla and the back sectors in both arches, as well as the loss of that osteointegration in the fixed bridge.

Integración de los aloinjertos óseos impregnados con alendronato. Estudio experimental / Alendronate-impregnated bone allograft integration. Experimental study

Introducción: El propósito de este estudio experimental es investigar la variabilidad en la reabsorción ósea de aloinjertos impregnados con alendronato respecto a aloinjertos sin impregnación con alendronato. Materiales y Métodos: Se utilizaron 18 conejos neozelandeses, divididos en dos grupos de 9 animales cada uno. Se trabajó sobre el fémur derecho, se realizó una ventana ósea y se colocó aloinjerto con alendronato local en el grupo I y aloinjerto sin alendronato en el grupo II. Todos fueron sacrificados a las 10 semanas del procedimiento inicial, y se valoró el fémur operado con anatomía patológica, radiografías de frente y de perfil, y tomografía axial computarizada. Se evaluaron la osteointegración, la vascularización y la calidad ósea. Resultados: El estudio histológico demostró mayor osteointegración en el grupo I que en el grupo II (p = 0,003), y fenómenos bien definidos de “acoplamiento” entre el tejido óseo receptor e injertado, leve actividad osteoclástica. En el grupo II, se observó menor acoplamiento óseo (osteointegración). La evaluación de la reabsorción ósea con radiografía y tomografía computarizada no reveló una diferencia estadísticamente significativa entre ambos grupos. En el grupo I, se observó mayor osteointegración del aloinjerto (p = 0,577; no significativo). Conclusión: Los resultados obtenidos en este trabajo experimental muestran que el alendronato local asociado a aloinjertos ayuda a mejorar la osteointegración de los aloinjertos, que es un método seguro, y que no se asocia a riesgos locales o sistémicos en conejos, aun en dosis elevadas.

Background: The use of allografts in bone reconstruction may be associated with an increased absorption of the latter, which may cause loss of stability and failure of reconstructions. The purpose of this experimental study was to investigate the variability in bone resorption in alendronate impregnated allografts versus non-impregnated allografts. Methods: Eighteen New Zealand rabbits were divided into two groups of nine animals each. We worked on the right femur; a bone window was performed and allografts were placed (with alendronate in group I and without alendronate in group II). All rabbits were sacrificed at 10 weeks after the initial procedure. Femur was evaluated with pathology, frontal and lateral radiographs and computed tomography. Osteointegration, vascularization and bone quality were evaluated. Results: No deaths or infections were reported, with 18 rabbits up to final analysis. histology showed better osteointegration in group I than group II (p = 0.003), with well-defined attachment between receptor bone tissue and low osteoclastic activity. In group II, we observed less osteointegration. Assessment of bone resorption with radiographs and computed tomography showed no statistically significant difference between both groups. Group I showed more osteointegration of the allograft (p = 0.577; not significant). Conclusions: Results of this experimental study show that allografts impregnated with alendronate help to improve the osteointegration. Also, it is a safe way and it is not associated with local or systemic risks in rabbits, even with high doses of alendronate.

Dor persistente, anormalidades sensitivas, lesão de nervo e perda do implante após cirurgia com implantes dentais: sugestão deabordagem clínica / Persistent pain, sensory abnormalities, nervous injury and loss of implantafter dental implant surgery: clinical approach suggestion

JUSTIFICATIVA E OBJETIVOS: Alterações de sensibilidade trigeminal podem levar à dor neuropática após manipulação cirúrgica. Essas queixas geram dúvidas. Primeiro:são reais? Pois, nem sempre há relação causal entre implante-nervo. Segundo: o implante deve ser removido? O objetivo deste estudo foi rever a literatura sobre o assunto.CONTEÚDO: A literatura é farta em informações sobre perdas de implantes relacionadas à osteointegração, mas são raros os estudos sobre perdas relacionadas à lesão de nervo ou à dor neuropática. O risco para longevidade de implantes é multifatorial. Contribuem: saúde do paciente,técnica cirúrgica, região receptora e ativação funcional,entre outros fatores. Dor é complicação com significativas implicações clínicas, psicológicas, sociais e legais; exigindo atenção especial aos pacientes, muitas vezes prolongada ou permanente. Atualmente a literatura especializada já é volumosa sobre prevalência de anormalidades sensitivas e lesão de nervo após procedimentos odontológicos. Em conjunto, essas informações sugerem conduta que inclua exame minucioso, interconsultas e adoção de medidas preventivas, curativas ou paliativas para o tratamentoda dor. A remoção do implante depende dessa análise,portanto, nem sempre é uma decisão simples.CONCLUSÃO: Informações sobre remoção de implantes dentais devido à dor ou lesão de nervo são escassas nem sempre homogêneas, porém já alertam de que essa decisão nem sempre é simples. Ela depende da adoção de medidas diagnósticas, algumas especializadas, incluindoos exames de imagem. Diagnóstico e tratamento precoceda lesão de nervo e da dor neuropática são benéficos ao paciente e têm importantes implicações éticas e legais.

BACKGROUND AND OBJECTIVES: Trigeminal sensitivity changes may lead to neuropathic pain after surgical handling. These complaints generate questions.First: are they real? Because a causal relationship between implant and nerve is not always present. Second: shouldthe implant be removed? This study aimed at reviewing the literature on the subject.CONTENTS: The literature is prodigal on information about loss of implants related to osteointegration, butthere are few studies on losses related to nerve loss or to neuropathic pain. The risk for implants longevity is multifactorial.Contributors are: patients' health, surgical technique, receptor region and functional activation, amongo ther factors. Pain is a complication with significant clinical,psychological, social and legal implications, requiring special attention to patients, very often prolonged or permanent. Currently, specialized literature is already voluminous about the prevalence of sensory abnormalities and nervous injury after dental procedures. Together,these pieces of information suggest an approach including detailed exams, inter consultations and the adoption of preventive, curative or palliative measures to treat pain. Implant removal depends on this analysis and it is not always a simple decision. CONCLUSION: Information about dental implants removal due to pain or nervous injury is scarce and notalways homogeneous, however it already calls the attention to the fact that such decision is not always simple. It depends on the adoption of diagnostic measures, some of them specialized, including image exams. Early diagnosis and treatment of nervous injury and neuropathic pain are beneficial to patients and have major ethic and legal implications.

Effects of bone marrow stromal stem cells on bone defect around the implant and osteointegration of implant-bone interface / 中国矫形外科杂志

[Objective]To investigate the effects of bone marrow stromal stem cells(MSCs) on the bone defect around the implant and the osteointegration of implant-bone interface.[Method]Fifteen healthy clean New Zealand rabbits were studied.MSCs were separated,cultured and induced to osteoblasts.Cancellous bone defects(0.6?1.2 cm)were created in bilateral femur condyle in rabbits.Titanium alloy columns(0.3?1.0 cm)were implanted into both defects.Tissue engineering bone was implanted around the left titanium alloy implant,but only hydroxyapatite ceramic in the right.The biological characteristics were evaluated by X-ray examination,SEM,energy dispersive X-ray analysis and histologic studies at 4,8,and 12 weeks postoperatively.[Result] X-ray examination showed the density of bone tissue around the implant was aequalis.The interspace between implant and bone was filled with lots of bone trabeculae in the experimental group at 12 weeks postoperatively.The density of bone tissue was inhomogeneous,and low-density umbra existed in the interspace in the control group.Energy dispersive X-ray analysis showed the content of the Ca and P in the experimental group was statistically higher than that in the control group at different time points(P0.05.The ratio of Ca to P became higher and reaching the peak level at 8 week.Histological study showed the bone defects around the implant were repaired by new mature bone in the left at 12 weeks postoperatively,while in the right no new bone was found at any time point.[Conclusion]The compounds of hydroxyapatite ceramic and osteoblasts induced by MSCs can repair the bone defect around the implant and improve the osteointegration of implant-bone interface.

Stability and Efficacy of Titanium in Osteointegration in a Rabbit Model

Osteointegration with titanium implant has become a highlight having titanium implant tightly fixed in the bone with prosthesis attaching over it. The procedure is relatively simple with no morbidity of donor site and ensues superior shape aesthetically. However, the stability of it has been in question, therefore an experiment was performed to study the actual stability and periosteal formation around the implant. This study presents a histomorphometric and biomechanical comparison of bone response between titanium and stainless steel placed in the tibia of 5 rabbits. Two implants were placed in tibia of rabbit; titanium implant in left and stainless steel implant as a control in right. As a titanium implant, Brnemark implant with depth of 4 mm and diameter of 3.75 mm which has actually been used in the reconstruction of ears was used, and the stainless steel was manufactured in the same way as titanium implant. After a healing period of 3 months, the average removal torque was 8.2 Ncm for the stainless steel implants and 26.5 Ncm for the titanium implant. Histomorphometric study revealed that the stainless steel screw demonstrated rough and irregular contact surface with partial formation of new bone and the titanium implant demonstrated smooth contact surface with a good formation of new bone. In conclusion, the results indicated that titanium surfaces achieved greater periosteal bone formation over stainless steel surfaces and provided enhanced mechanical interlocking.