Three-dimensional finite element analysis of cement flow in abutment margin-crown platform switching / 北京大学学报(医学版)

OBJECTIVE@#To analyze the cement flow in the abutment margin-crown platform switching structure by using the three-dimensional finite element analysis, in order to prove that whether the abutment margin-crown platform switching structure can reduce the inflow depth of cement in the implantation adhesive retention.@*METHODS@#By using ANSYS 19.0 software, two models were created, including the one with regular margin and crown (Model one, the traditional group), and the other one with abutment margin-crown platform switching structure (Model two, the platform switching group). Both abutments of the two models were wrapped by gingiva, and the depth of the abutment margins was 1.5 mm submucosal. Two-way fluid structure coupling calculations were produced in two models by using ANSYS 19.0 software. In the two models, the same amount of cement were put between the inner side of the crowns and the abutments. The process of cementing the crown to the abutment was simulated when the crown was 0.6 mm above the abutment. The crown was falling at a constant speed in the whole process spending 0.1 s. Then we observed the cement flow outside the crowns at the time of 0.025 s, 0.05 s, 0.075 s, 0.1 s, and measured the depth of cement over the margins at the time of 0.1 s.@*RESULTS@#At the time of 0 s, 0.025 s, 0.05 s, the cements in the two models were all above the abutment margins. At the time of 0.075 s, in Model one, the gingiva was squeezed by the cement and became deformed, and then a gap was formed between the gingiva and the abutment into which the cement started to flow. In Model two, because of the narrow neck of the crown, the cement flowed out from the gingival as it was pressed by the upward counterforce from the gingival and the abutment margin. At the time of 0.1 s, in Model one, the cement continued to flow deep inside with the gravity force and pressure, and the depth of the cement over the margin was 1 mm. In Model two, the cement continued to flow out from the gingival at the time of 0.075 s, and the depth of the cement over the margin was 0 mm.@*CONCLUSION@#When the abutment was wrapped by the gingiva, the inflow depth of cement in the implantation adhesive retention can be reduced in the abutment margin-crown platform switching structure.

Peri-implant bone level assessment of early loaded dental implants submitted to different prosthetic protocols: a case report / Avaliação do nível ósseo peri-implantar de implantes dentários com carregamento antecipado submetidos a protocolos protéticos diferentes: relato de caso

Aim: The present split-mouth case report aims to describe the clinical and radiographic long-term outcomes of the implant rehabilitation of two mandibular premolars in which the digital workflow was used to apply different prosthetic protocols. Case description: A female 42-year-old patient with the absence of both mandibular second premolars was submitted to guided surgery for the placement of platform-switching Grand Morse connection implants. Digital workflow was used for implant and prosthetic planning, applying early loading protocol 21 days after surgery. The implant on the right side received the final abutment at the time of surgery (without loading), whereas the implant on the left side had a healing abutment placed, which was replaced by a temporary abutment and then by a final abutment. Two months after surgery, both implants had final ceramic restorations delivered. The patient was followed clinically and radiographically for 30 months, presenting excellent hard and soft tissue outcomes, with bone level changes lower than 2mm for both implants. Conclusion: The use of digital workflow and early loading, made the present implant-supported rehabilitation predictable, safe and time-efficient, resulting in total patient satisfaction. Peri-implant bone level was observed to be stable after early loading protocol for both platform-switching connection implants inserted, despite the prosthetic protocol applied.(AU)

Objetivo: O presente relato de caso de boca dividida tem como objetivo descrever os resultados clínicos e radiográficos a longo prazo da reabilitação com implante de dois pré-molares inferiores em que o fluxo de trabalho digital foi usado para aplicar os conceitos de "one abutment-one time" em uma das reabilitações e troca de componente no outro. Descrição do caso: Paciente do sexo feminino, 42 anos, com ausência de ambos os segundos pré-molares inferiores, foi submetida à cirurgia guiada para colocação de implantes de conexão Grand Morse plataforma-switching. Foi utilizado fluxo de trabalho digital para planejamento de implante e prótese, aplicando protocolo de carga antecipada 21 dias após a cirurgia. O implante do lado direito recebeu o componente protético definitivo no momento da cirurgia (sem carga), enquanto o implante do lado esquerdo recebeu um cicatrizador, que foi substituído por um pilar provisório e depois por um componente definitivo. Dois meses após a cirurgia, ambos os implantes tiveram restaurações cerâmicas finais entregues. A paciente foi acompanhada clínica e radiograficamente por 30 meses, apresentando excelentes resultados de tecidos duros emoles, com alterações do nível ósseo inferiores a 2mm para ambos os implantes. Conclusão: O fluxo de trabalho digital e carregamento precoce, tornou a presente reabilitação implantossuportada previsível, segura e eficiente em termos de tempo, resultando em total satisfação do paciente. O nível ósseo peri-implantar foi observado como estável após o protocolo de carregamento inicial para ambos os implantes de conexão plataforma-switching inseridos, independente do protocolo protético aplicado. (AU)

Clinical application of platform switching implants in maxillary anterior region / 口腔疾病防治

Objective@#To evaluate the application effect of the platform switching implants in maxillary anterior region, to explore the effect of platform switching technology on the surrounding tissues. @*Methods@# 55 patients with 60 single maxillary anterior implants were divided into two groups: platform-switching implants group (Ankylos), 25 patients with 28 implants; butt-joint implants group (Nobel Replace), 30 patients with 32 implants. The patients received follow-up care more than 1 and 2 year after the final setting of the prosthesis, at which time periapical radiographs were taken. The marginal bone level around the implant and Pink Esthetic Score (PES) were measured for comparison. @* Results @#The average marginal bone changes of platform-switching implants after 1 year and 2 year were (-0.41 ± 0.36) mm and (-0.55 ± 0.33) mm respectively; and the ones of butt-joint implants were (-1.77 ± 0.54) mm and (-1.82 ± 0.61) mm. The average PES of platform- switched implants after 1 year and 2 year were 10.43 ± 1.37 and 10.32 ± 1.21 respectively; the ones of butt-joint implants were 9.21 ± 0.97 and 9.16 ± 0.95. There were significantly differences of marginal bone changes and PES between both groups (P < 0.05).@*Conclusion @#Platform switching implant in the maxillary aesthetics area is more effective in preserving the surrounding bone tissue and aesthetic effect.

Three-dimensional finite element analysis of platform switched implant

PURPOSE: The purpose of this study was to analyze the influence of the platform switching concept on an implant system and peri-implant bone using three-dimensional finite element analysis. MATERIALS AND METHODS: Two three-dimensional finite element models for wide platform and platform switching were created. In the wide platform model, a wide platform abutment was connected to a wide platform implant. In the platform switching model, the wide platform abutment of the wide platform model was replaced by a regular platform abutment. A contact condition was set between the implant components. A vertical load of 300 N was applied to the crown. The maximum von Mises stress values and displacements of the two models were compared to analyze the biomechanical behavior of the models. RESULTS: In the two models, the stress was mainly concentrated at the bottom of the abutment and the top surface of the implant in both models. However, the von Mises stress values were much higher in the platform switching model in most of the components, except for the bone. The highest von Mises values and stress distribution pattern of the bone were similar in the two models. The components of the platform switching model showed greater displacement than those of the wide platform model. CONCLUSION: Due to the stress concentration generated in the implant and the prosthodontic components of the platform switched implant, the mechanical complications might occur when platform switching concept is used.

Assessment of Marginal Bone Loss around Platform-Matched and Platform-Switched Implants - A Prospective Study

Abstract The aim of the present study was to perform a software-assisted radiographic assessment of the effect of platform-switching on marginal bone loss (MBL) around dental implants. Forty patients requiring a dental implant in non-grafted partially edentulous mandibles were enrolled and categorized into implants receiving a platform-matched abutment (control group) or implants with a platform-switched abutment (test group). Standardized digital periapical radiographs were taken at the time of implant placement (T0), at implant loading (T1) and 1-year after functional loading (T2). Software-assisted radiographic assessment of the MBL horizontal, vertical and area changes was performed and compared between time intervals (T1-T0, T2-T1 and T2-T0). Mean radiographic horizontal MBL (hMBL) and vertical MBL (vMBL) from implant placement to 1-year after implant loading (T2-T0) were significantly increased around platform-matched when compared to platform-switched abutments (1.04 mm vs 0.84 mm, p<0.05) and (0.99 mm vs 0.82 mm, p<0.05), respectively. Additionally, bone loss area (BLa) was greater (0.77 mm2 vs 0.63 mm2; p<0.05) for platform-matched compared to platform-switched abutments. Platform-switching has a positive impact upon the amount of bone modeling after loading implants with internal hexagon connection.

Resumo O objetivo do presente estudo foi realizar uma avaliação radiográfica assistida por computador do efeito da plataforma reduzida sobre a perda óssea marginal (MBL) ao redor de implantes. Quarenta pacientes que necessitavam um implante em mandíbulas parcialmente edêntulas não enxertadas foram selecionados e divididos em implantes que receberam pilares de plataforma igualada (grupo controle) ou implantes com pilares de plataforma reduzida (grupo teste). Radiografias periapicais digitais padronizadas foram realizadas no momento da instalação do implante (T0), carregamento do implante (T1) e 1 ano após carregamento funcional (T2). Avaliação radiográfica assistida por computador da MBL horizontal, vertical e mudanças de área foi realizada e comparada entre os intervalos de tempo (T1-T0, T2-T1 e T2-T0). A média radiográfica da MBL horizontal (hMBL) e da MBL vertical (vMBL) do momento da instalação do implante até 1 ano após carregamento (T2-T0) foram significativamente aumentadas ao redor dos pilares de plataforma igualada quando comparado com os pilares de plataforma reduzida (1,04 mm vs 0,84 mm, p<0,05) e (0,99 mm vs 0,82,mm, p<0,05), respectivamente. Além disso, a área de perda óssea (BLa) foi maior (0,77 mm2 vs 0,63 mm2; p<0,05) para plataforma igualada comparada com pilares de plataforma reduzida. Plataforma reduzida tem um impacto positivo na remodelação óssea após carregamento de implantes com conexão interna hexagonal.

Implantes de diâmetro reduzido (< 3 mm) para reabilitação oral de espaços edêntulos atrésicos em pacientes adolescentes ­ relato de caso com acompanhamento de um ano / Reduced diameter dental implants (< 3 mm) for oral rehabilitation of edentulous atresic spaces

Reabilitações estéticas em áreas anteriores com limitação de espaço mesiodistal tornam-se um desafio. Entretanto, implantes dentários de diâmetros reduzidos (< 3 mm) têm sido utilizados nestes casos. Este relato de caso apresenta a utilização de dois implantes de diâmetro reduzido (2,8 mm) e conexão morse no tratamento de agenesia de laterais superiores. Após planejamento cirúrgico-protético, os implantes foram restaurados imediatamente e acompanhados por um período de um ano. Dentro das limitações deste trabalho, sugere-se que implantes de diâmetro reduzido podem ser utilizados com sucesso para a restauração imediata de laterais superiores, oferecendo um bom perfil de emergência protética e estética para dentes estreitos.

Esthetic rehabilitations in the anterior zones with limited mesiodistal spaces are a great challenge. However, dental implants with reduced diameters (< 3 mm) with a morse taper connection have been used in cases os lateral incisor agenesis. After a detailed surgical-prosthetic planning, the dental implants were immediately restored and followed-up for one year. Within the limits of this paper, it can be suggested that narrower dental implantes can be used with success in such situations, providing a good emergence profile and esthetics to for narrower dental spaces.

Biomecânica da união dente-implante com plataforma restauradora reduzida, sistema de retenção tipo cone morse e roscas quadradas: uma análise por elementos finitos / Biomechanics of tooth-implant union with restorative platform reduced, restraint system morse cone type and square threads: a finite element analysis

Objetivou-se, a partir do Método dos Elementos Finitos, avaliar a biomecânica da união dente-implante e implante-implante, além de estabelecer uma análise qualitativa com achados fotoelásticos prévios. Foram planejados quatro modelos tridimensionais: dois Modelos Teste (dentes unidos a implantes) e dois Modelos Controle (a mesma condição, porém implanto suportada). Os implantes (ANKYLOS® - Dentsply) apresentaram conexão cônica, roscas quadradas e pilares Switching. Suas dimensões, ângulos externos e pilares protéticos foram obtidos a partir de um projetor de perfil. Já, dentes e próteses, a partir da visão direta, tiveram suas formas externas construídas em plataforma CAD (SOLIDSWORKS). O suporte alveolar foi configurado como um retângulo (68/30/15 mm). Todos os pilares foram posicionados no suporte alveolar, conforme os modelos físicos pré-existentes, gerando modelos sólidos. O ligamento periodontal consistiu de uma camada de 0,25 mm de espessura em poliéter (Impregum Soft, 3M Espe). Os modelos de dentes foram produzidos em dentina, pilares e implantes em titânio puro, próteses em liga Níquel-Cromo (Ni-Cr), e o suporte alveolar em resina fotoelástica (Araldite® - Produtos Químicos Ciba S/A do Brasil). As propriedades da resina foram obtidas por meio de ensaio de tração. Carga pontual, vertical e estática, de 150 N, foi aplicada. Os resultados destes ensaios evidenciaram menor concentração de tensão no aspecto cervical de implantes do grupo teste. Ao se confrontar tais achados com os fotoelásticos anteriormente obtidos, foi possível estabelecer uma relação direta entre as áreas mais solicitadas para os modelos de prótese fixa (PF) de três elementos. Concluiu-se que, para as condições estudadas ¿ conexão cônica, roscas quadradas e restauração com Plataforma Switching ¿, unir dentes a implantes parece ser uma terapia clínica viável, sugerindo, inclusive, ser mais favorável que a união de implantes entre si. Além disso, a partir da afinidade positiva entre os achados das duas técnicas, pôde-se considerar validados os modelos matemáticos de prótese fixa de três elementos

The goal of this study was to evaluate, from the Finite Element Method, the biomechanics of implant-tooth union and implant-implant and to establish a qualitative analysis with previous photoelastic findings. Four three-dimensional models were planned: two Test Models (teeth attached to implants) and two Control Models (the same condition, however implant supported). The implants (ANKYLOS® - Dentsply) showed conical connection, square threads and Switching pillars. Their dimensions, external angles and abutments were obtained from a profile projector. Already, teeth and dentures, from direct view, had their external forms built in CAD platform (SOLIDSWORKS). Alveolar support wasconfigured as a rectangle (68/30/15 mm). All the pillars were placed in the alveolar support, as the pre-existing physical models, generating solid models. The periodontal ligament consists of a layer of 0.25 mm thick in polyether (Impregum Soft, 3M Espe). The models of teeth trumped up of dentin, abutments and implants of pure titanium, prosthetics of Nickel-Chrome (Ni-Cr) alloy and alveolar support in photoelastic resin (Araldite® - Chemicals Ciba S/A of Brazil). The resin properties were obtained by traction tests. Punctual and vertical static load of 150 N was applied. The results of these tests showed lower concentration of tension in the cervical aspect of the test group implants. When comparing these findings with the photoelastic previously found, it was possible to establish a direct relation between the areas most requested for fixed prosthesis (FP) models of three elements. It was concluded that, for the studied conditions tapered connection, square threads and Platform Switching restoration , joining teeth implants seems to be a viable clinical therapy, suggesting, inclusive, to be more favorable than to join implants each other. Moreover, from the positive affinity between the findings of the two techniques, it was possible to consider validated the mathematical models of fixed prosthesis of three elements

Narrow-diameter implants with conical connection for restoring the posterior edentulous region / 대한악안면성형재건외과학회지

BACKGROUND: The objective of this retrospective study was to show results from platform-switched narrow-diameter implants in the posterior edentulous region, which we followed up for more than 1 year after functional loading. METHODS: Ninety-eight narrow implants were inserted into 66 patients. After healing, fixed implant-supported prostheses were delivered to the patients, and Periotest and radiographic examinations were performed. After the first year of loading, the implant outcome was again evaluated clinically and radiographically using the Periotest analysis. Crestal bone loss and Periotest values (PTVs) were used to evaluate the effect of surgery, prosthesis, implant, and a host-related factor. A general linear model was used to statistically detect variables statistically associated with crestal bone loss and Periotest value. RESULTS: We followed up on the implants over 1 to 4 years after loading; their survival rate was 100%, and pronounced differences from PTVs were noted among jaw location, bone quality, and loading period. No difference was detected in bone loss among the variables studied. Bone loss after functional loading was 0.14 ± 0.39 mm. The stability value from the Periotest was −3.29 ± 0.50. CONCLUSIONS: Within the limitations of this study, judicious use of platform-switched narrow implants with a conical connection must be considered an alternative for wide-diameter implants to restore a posterior edentulous region.

Clinical study of the influence on marginal bone levers when open healing of implants with platform ;switching / 实用医学杂志

Objective The study examined the influence on marginal bone levers at implants which implants were assigned to open healing and implant-abutment connection restored according to a platform-switching concept. Methods One implant were placed in the first molar of mandible of 48 patients , randomly assigned to open (OH) or submerge (SH) healing. Standardized radiographs were obtained after implant surgery, when implant transfer and crown mounting, and 6 ,12 and 24 months after implants restoration, then evaluated for implant-bone-lever alterations(ΔIBL). Results After 6 months after implants restoration,ΔIBL were (-0.25 ± 0.08)mm mm(OH)and (-0.26 ± 0.12)mm(SH). After 12 months follow-up, ΔIBL were (-0.29 ± 0.13)mm (OH)and (-0.31 ± 0.14) mm(SH), and after 24 months later, ΔIBLwere (-0.34 ± 0.15)mm(OH)and (-0.33 ± 0.11)mm (SH). Conclusions Platform-switched implants showed very limited peri-implant bone-lever alterations. The healing-mode neither affected the total amount nor the temporal patterns of ΔIBL.

Clinical effect observation of Dentium implant completed by once procedure / 中国基层医药

Objective To observe and evaluate the clinical effect of Dentium planting system by once procedure.Methods A total of 45 patients who had 55 Dentium implants implanted were followed up for one year. Permanent restorations were finished 12 weeks after once procedure.Clinical effects were evaluated through clinical and imaging examination.Results Through the 55 Dentium implants of 45 patients,the success rate was 100%.All patients were satisfied with aesthetics and occlusal function.Conclusion Dentium implant completed by once procedure is safe and reliable with once procedure on clinical application.Both the survival rate and successful rate of implants were 100%.High degree of satisfaction from patients was achieved.Both bone tissue and soft tissue are well preserved.This system can obviously reduce bone resorption and improve aesthetic effect.

Periointegración / Periointegration

Se busca entender cuáles son las respuestas biológicas que se dan en diferentes etapas de la implantología, centrando la atención en la influencia de la tecnología en la formación del ancho biológico. Se analiza cómo fue evolucionando la ciencia en la búsqueda de mejores respuestas y cuáles serán los factores decisivos para que la tecnología influencie a la biología y poder aproximarse cada vez más a lo natural.

The aim of this paper is to understand the biological responses at the different stages of implantology, with a focus on the influence of technology in the formation of the biological width. It presents a study of the evolution of science towards better responses and the determining factors for technology to influence biology, which allow us to get closer to what is natural.

Effect of Mechanical Cycling on Screw Torque in External Hexagon Implants with and without Platform Switching

This in vitro study evaluated the effect of mechanical cycling on the torque of retaining screw in external hexagon implants with platform switching (PS), regular platform (RP) and wide platform (WP). A total of 30 specimens were equally divided into 3 groups: PS, PR and WP. Each specimen was prepared with implants: 3.75 x 10 mm for RP group and 5.0x10 mm for PS and WP groups and its respective abutment with 32 Ncm torque. All groups were subjected to 106 cycles with 100 N (corresponding to about 40 months of chewing). The results were obtained with the reverse torque of each specimen and data were evaluated using ANOVA and Tukey test (p<0.05). The PS group showed statistically significant difference in screw removal torque (30.06±5.42) compared with RP (23.75±2.76) and WP (21.32±3.53) (p<0.05) groups; the RP and WP groups showed no statistically significant difference between them. It was concluded that the PS group showed higher reverse torque value, suggesting lower susceptibility of the abutment screw loosening.

Este estudo in vitro avaliou o efeito da ciclagem mecânica no torque dos parafusos de retenção em implantes de hexágono externo com plataforma switching (PS), plataforma regular (RP) e plataforma larga (WP). Foram utilizados 30 corpos de prova divididos em 3 grupos equitativamente: PS, RP e WP. Cada corpo de prova foi preparado com implantes: 3,75x10 mm para o grupo RP e 5,0x10 mm para os grupos PS e WP, e seu respectivo abutment com o torque de 32 Ncm. Todos os grupos foram submetidos a 106 ciclos com 100 N de força (o que corresponde a aproximadamente 40 meses de mastigação). Os resultados foram obtidos com o torque reverso de cada espécime e os dados foram avaliados com ANOVA comparado com o teste de Tukey (p<0,05). O grupo PS apresentou diferença estatisticamente significante no torque de remoção do parafuso (30,06±5,42) comparado com os grupos RP (23,75±2,76) e WP (21,32±3,53) (p<0,05); os grupos RP e WP não apresentaram diferença estatisticamente significante entre si. Concluiu-se que o grupo PS apresentou maior valor de torque reverso sugerindo menor susceptibilidade de afrouxamento do parafuso de fixação do abutment.

Influencia del Diseño Micro y Macroscópico de la Región Cervical del Implante en la Preservación de Hueso Marginal Perimplantario: Una Revisión Sistemática / Influence of the Micro and Macroscopic Implant Neck Design in the Preservation of Marginal Bone Level: A Systematic Review

El objetivo de esta revisión sistemática fue evaluar los distintos diseños en el cuello del implante (pulido o tratado, con o sin intercambio de plataforma, o con o sin microespiras) y su posible influencia en la pérdida del hueso marginal periimplantario. Se llevo a cabo una revisión sistemática siguiendo la metodología PICO del Centro de Medicina Basada en la Evidencia de la Universidad de Oxford. La pregunta dirigida a la consecución de los objetivos fue: ¿Es el diseño del cuello del implante un factor crítico en la conservación del hueso marginal periimplantario? Se emplearon MeSH keywords específicos en las bases de datos Pubmed y Cochrane. Tres revisores independientes se pusieron de acuerdo en los estudios finalmente incluidos, obteniendo un índice de concordancia kappa de 0,88. De estos, se realizó una evaluación crítica del nivel de evidencia y también del riesgo de sesgo de los RCT mediante la Herramienta Cochrane. Se consultaron 445 artículos por título, incluyendo finalmente un total de 16 artículos a texto completo. La heterogeneidad de estos estudios impidió realizar un meta-análisis. No se encontró evidencia de que una determinada configuración del cuello del implante sea mejor que otra en la conservación del hueso marginal periimplantario y sin embargo, parece que una posición apico-coronal yuxtaósea del cuello pulido del implante respecto a la cresta ósea receptora pudiera ser crítica a ese respecto. No se encontró suficiente evidencia sobre la efectividad de las diferentes configuraciones de la región cervical del implante en la preservación del hueso marginal periimplantario. Son necesarios estudios clínicos controlados y aleatorizados a largo plazo para valorar los efectos de dichas modificaciones.

The aim of this systematic review was to assess whether different implant neck designs (polished or coated, with or without platform switching, either with or without microthreads) influence marginal bone resorption. A systematic review was conducted following the PICO methodology of the Centre for Evidence-Based Medicine of Oxford University. The question to the achievement of objectives was: Is the design of the implant neck a critical factor in the preservation of marginal bone levels? Specific MeSH keywords were used in the Pubmed and Cochrane databases. Three independent reviewers agreed on the studies ultimately included finding a concordance kappa index of 0.86. Of these articles, acritical evaluation of the level of evidence was performed and also the risk of bias of the RCT using the Cochrane tool. Four hundred forty-five items were reviewed by title, eventually including a total of 16 full-text articles. Heterogeneity of these studies made impossible the performance of a meta-analysis. No evidence that a particular configuration of the implant neck was better than another in preserving the peri-implant marginal bone was found, and yet it seems that an apico-coronal position juxta-osseous of the smooth neck of the implant relative to the bone crest could be decisive. Not enough evidence was found on the effectiveness of different configurations of the cervical region of the implant in the periimplant marginal bone preservation. More randomized controlled trials are needed to assess long-term effects of such modifications.

Influence of platform switching versus platform matching on the marginal bone resorption around im-plant:A Meta-analysis / 实用口腔医学杂志

Objective:To evaluate the effects of platform switching and platform matching system on the marginal bone resorption a-round implant.Methods:Randomized controlled trials (RCTs)that compared marginal bone loss around platform-switched implants with platform matched prostheses were selected from PubMed,EMbase,CBM,CNKI and other electronic databases supplemented by hand search and retrospective collection of literature published or unpublished between 1 991 -201 4.The literature based on inclusion and exclusion criteria was screened by 2 revieweres independently,the quality of the included studies was evaluated,the data were extracted using RevMan 5.2 software for Meta-analysis.Results:1 4 studies with 1 331 implants were included.Meta-analysis showed that peri-implant bone resorption in the platform switching group was significantly less than that in the platform matching group[MD =-0.51 ,95% CI:(-0.72 -0.30),P 0.45 mm (unilateral)was more favorable to implant marginal bone preservation.Conclusion:The present data suggest that platform-switched technology is more conducive to implant bone preservation than platform-matched method.

“Platform switching”: Serendipity.

Implant dentistry is the latest developing field in terms of clinical techniques, research, material science and oral rehabilitation. Extensive work is being done to improve the designing of implants in order to achieve better esthetics and function. The main drawback with respect to implant restoration is achieving good osseointegration along with satisfactory stress distribution, which in turn will improve the prognosis of implant prosthesis by reducing the crestal bone loss. Many concepts have been developed with reference to surface coating of implants, surgical techniques for implant placement, immediate and delayed loading, platform switching concept, etc. This article has made an attempt to review the concept of platform switching was in fact revealed accidentally due to the nonavailability of the abutment appropriate to the size of the implant placed. A few aspect of platform switching, an upcoming idea to reduce crestal bone loss have been covered. The various methods used for locating and preparing the data were done through textbooks, Google search and related articles.

Reabilitação da mandíbula edêntula com implantes e coroas metalocerâmicas isoladas implantossuportadas: relato de caso clínico com sistema CAD/CAM / Rehabilitation of the edentulous mandible using single-tooth, implant-supported metal-ceramic crowns: case report with CAD/CAM system

A forma mais comum de reabilitação de mandíbulas edêntulas com implantes osseointegrados é a prótese total fixa parafusada tipo protocolo de Brånemark, na qual os implantes são esplintados. Este relato de caso clínico apresenta uma forma alternativa de reabilitação total de mandíbulas edêntulas, com 14 implantes cone-morse e coroas totais metalocerâmicas isoladas. Foram discutidos aspectos referentes ao planejamento, com ênfase no planejamento virtual, na necessidade de disponibilidade óssea para realização deste tipo de tratamento, nas facilidades de higienização desta modalidade de reabilitação, nas considerações biomecânicas do caso, sobretudo quanto aos possíveis riscos em manter os implantes isolados, na seleção adequada dos implantes e dos componentes protéticos, nos benefícios do conceito de platform switching incorporados aos implantes cone-morse, nos cuidados necessários de manutenção, entre outros aspectos. A técnica é extremamente delicada em todas as suas etapas, sobretudo nas fases de planejamento e cirúrgica, visando a excelência do posicionamento dos implantes, para permitir a utilização de componentes protéticos pré-fabricados (munhões universais retos) sem a necessidade de usinagem. Este tipo de reabilitação mandibular mostrou-se muito eficiente, apresentando como principais vantagens a estética otimizada, a facilidade de higienização, o aspecto emocional muito favorável e uma extrema satisfação da paciente.

The most common treatment type for edentulous mandible is the full-fixed prosthesis according to the Branemark protocol with splinted dental implants. This case report presents an alternative option with cone Morse implants, straight universal abutments, and single metal-ceramic crowns. Aspects such as virtual implant planning, bone availability, biomechanical risks for single-tooth implants, prosthetic component selection, platform-switching, and maintenance are discussed, among others. The technique is very delicate in each step, particularly at surgery and three-dimensional implant positioning for pre-fabricated prosthetic components (straight universal abutments) without previous modifications. This kind of mandibular rehabilitation was very efficient and has the advantages of esthetics, easy cleaning, favorable emotional aspects and good patient satisfaction.

Influence of the implant-abutment connection design and diameter on the screw joint stability

PURPOSE: This study was conducted to evaluate the influence of the implant-abutment connection design and diameter on the screw joint stability. MATERIALS AND METHODS: Regular and wide-diameter implant systems with three different joint connection designs: an external butt joint, a one-stage internal cone, and a two-stage internal cone were divided into seven groups (n=5, in each group). The initial removal torque values of the abutment screw were measured with a digital torque gauge. The postload removal torque values were measured after 100,000 cycles of a 150 N and a 10 Hz cyclic load had been applied. Subsequently, the rates of the initial and postload removal torque losses were calculated to evaluate the effect of the joint connection design and diameter on the screw joint stability. Each group was compared using Kruskal-Wallis test and Mann-Whitney U test as post-hoc test (alpha=0.05). RESULTS: The postload removal torque value was high in the following order with regard to magnitude: two-stage internal cone, one-stage internal cone, and external butt joint systems. In the regular-diameter group, the external butt joint and one-stage internal cone systems showed lower postload removal torque loss rates than the two-stage internal cone system. In the wide-diameter group, the external butt joint system showed a lower loss rate than the one-stage internal cone and two-stage internal cone systems. In the two-stage internal cone system, the wide-diameter group showed a significantly lower loss rate than the regular-diameter group (P<.05). CONCLUSION: The results of this study showed that the external butt joint was more advantageous than the internal cone in terms of the postload removal torque loss. For the difference in the implant diameter, a wide diameter was more advantageous in terms of the torque loss rate.

Implant crest module: A review of biomechanical considerations.

The success of dental implants has long been established through various studies with a particular emphasis laid on an implant design. Crest module is that portion of a two-piece metal dental implant, designed to hold the prosthetic components in place and to create a transition zone to the load bearing implant body. Its design, position in relation to the alveolar crest, and an abutment implant interface makes us believe that, it has a major role in integration to both hard and soft tissues. Unfortunately, in most clinical conditions, early tissue breakdown leading to soft tissue and hard tissue loss begins at this region. Early crestal bone loss is usually highest during the first year after placement ranging from 0.9 to 1.6mm and averaged 0.05-0.13mm in the subsequent years . Various hypotheses have been stated to reason it however, none has been proved convincingly. In light of this, various attempts have been made to overcome this undesirable bone loss, by varying an implant design, the position, surgical protocol, and the prosthetic options. Irrespective of an implant system and designs that are used, crestal bone loss of up to the first thread is often observed. The purpose of this review is to look into the various designs and treatment modalities, which have been introduced into the crest module of an implant body to achieve the best biomechanical and esthetic result.

Reabilitação da maxila edêntula com implantes e coroas metalocerâmicas CAD/CAM isoladas implantossuportadas: relato de caso / Rehabilitation of the edentulous maxilla using single-tooth, implant-supported CAD/CAM metalloceramic crowns: case report

A forma mais comum de reabilitação de maxilas totalmente edêntulas com implantes osseointegrados é a prótese total fixa parafusada tipo protocolo de Brånemark, na qual os implantes são esplintados. Este relato de caso clínico apresenta uma forma alternativa para reabilitação de maxilas edêntulas com 14 implantes de conexão cone-morse, pilares retos e coroas totais metalocerâmicas isoladas, com infra-estruturas em titânio, empregando-se a tecnologia CAD/CAM. Neste trabalho foram discutidos aspectos referentes ao planejamento, com ênfase ao planejamento virtual, à necessidade de disponibilidade óssea, às facilidades de higienização, biomecânica (possíveis riscos em manter os implantes isolados), à seleção adequada dos implantes e dos componentes protéticos, aos benefícios do conceito de platform switching, às facilidades de confecção das infra-estruturas em titânio pela tecnologia CAD/CAM, entre outros aspectos. Este tipo de reabilitação maxilar mostrou-se muito eficiente, apresentando como principais vantagens a estética melhorada, a facilidade de higienização, o aspecto emocional muito favorável e a satisfação do paciente.

Oral rehabilitation of completely edentulous maxillary arch has been represented by splinted osseointegrated implants according to classic Brånemark protocols. This case report presents an alternative approach with 14 cone-morse connection type implants, universal abutments, and single ceramic-veneered titanium frameworks using the CAD/CAM technology. All aspects regarding to the virtual treatment planning, bone availability, easiness of cleaning, biomechanics (non-splinted units), adequate implant and prosthetic component selection, the benefits of platform-switching mode, titanium framework fabrication using CAD/CAM technology, among others, are discussed as well. This modality demonstrated efficacy, improved esthetics and hygiene, also with a more favorable emotional aspect and patient satisfaction.

Crestal bone preservation: A review of different approaches for successful implant therapy.

The level of bone crest surrounding the implant is of utmost significance to determine osseointegrated implant success, as preservation of marginal bone height is highly important for long-term dental implant survival. Various approaches have been described in the literature to prevent the crestal bone loss, including platform switching, non-submerged approach, scalloped implants, implant design modifications, progressive loading, immediate implant placement, etc. The purpose of this paper is to review all the possible methods to preserve the crestal bone, when each method should be used and their success rates in an attempt to address this complex problem of crestal bone resorption. "PubMed" and "Google Scholar" were used to find out any studies involving platform switching concept from 1990 up to 2009. Twenty-four studies involving methods for preservation of crestal bone were evaluated, which included 26% studies on platform switching, 22% on non-submerged approach, 17% on scalloped implants, 13% on progressive loading and 22% on immediate implant placement. Crestal bone preservation should be thought of starting from the design of the implant to be placed. The technique to be followed in a given case will depend upon the density of bone, force factors by the patient, bone volume and amount of soft tissues, etc. The best possible method or the combination of the methods should be used to preserve the crestal bone for the long-term success of the implants.