One Abutment at One Time Concept for Platform-Switched Morse Implants: Systematic Review and Meta-Analysis

Abstract The aim of this systematic review and meta-analysis was to compare the peri-implant vertical bone loss of immediate loading of implant crowns using the one abutment at one time (AOT) protocol and implants with abutment removal (AR). This systematic review with meta-analysis was reported according to the PRISMA statement, with guidance from the Cochrane Collaboration Handbook. A total of 103 publications were identified in the PubMed database and reference lists of examined articles. After the screening of titles and abstracts, the eligibility of eight full-text articles was assessed. Five studies published between 2010 and 2015 were included in the meta-analysis. There was less peri-implant vertical bone loss at implants using an AOT protocol than at implants using AR protocol (WMD -0.19, 95% CI -0.26 to -0.13; p<0.0001; random-effects model). In conclusion, the use of the AOT protocol with platform-switched Morse implants results in less bone loss than do AR procedures, but this effect may not be clinically relevant. The preservation of marginal bone level achieved with the AOT protocol may not enhance the aesthetics. These results should be interpreted with caution.

Resumo O objetivo desta revisão sistemática e meta-análise foi comparar a perda óssea vertical em implantes de carga imediata usando o protocolo de um pilar em um único momento (AOT) e implantes com remoção de pilar (AR). Esta revisão sistemática com meta-análise foi relatada de acordo com a declaração PRISMA, com orientação do Cochrane Collaboration Handbook. Foram identificadas 103 publicações na base de dados PubMed e nas listas de referência dos artigos examinados. Após a triagem de títulos e resumos, avaliou-se a elegibilidade de oito artigos de texto completo. Cinco estudos publicados entre 2010 e 2015 foram incluídos na meta-análise. Houve menos perda óssea vertical peri-implante em implantes usando o protocolo AOT do que nos implantes usando o protocolo AR (WMD -0,19, 95% IC -0,26 a -0,13; p <0,0001, modelo de efeitos aleatórios). Em conclusão, o uso do protocolo AOT com implantes Cone Morse associados a pilares com plataforma switching resulta em menos perda óssea do que os procedimentos AR, mas esse efeito pode não ser clinicamente relevante. A preservação do nível ósseo marginal alcançado com o protocolo AOT pode não melhorar a estética. Estes resultados devem ser interpretados com cautela.

Influence of different abutment diameter of implants on the peri‑implant stress in the crestal bone: A Three‑dimensional finite element analysis ‑ In vitro study.

Purpose of the Study: The study was designed to evaluate and compare stress distribution in transcortical section of bone with normal abutment and platform switched abutment under vertical and oblique forces in posterior mandible region. Materials and Methods: A three‑dimensional finite element model was designed using ANSYS 13.0 software. The type of bone selection for the model was made of type II mandibular bone, having cortical bone thickness ranging from 0.595 mm to 1.515 mm with the crestal region measuring 1.5 mm surrounding dense trabecular bone. The implant will be modulated at 5 mm restorative platform and tapering down to 4.5 mm wide at the threads, 13 mm long with an abutment 3 mm in height. The models will be designed for two situations: (1) An implant with a 5 mm diameter abutment representing a standard platform in the posterior mandible region. (2) An implant with a 4.5 mm diameter abutment representing platform switching in the posterior mandible region. Force application was performed in both oblique and vertical conditions using 100 N as a representative masticatory force. For oblique loading, a force of 100 N was applied at 15° from the vertical axis. von Mises stress analysis was evaluated. Results: The results of the study showed cortical stress in the conventional and platform switching model under oblique forces were 59.329 MPa and 39.952 MPa, respectively. Cortical stress in the conventional and platform switching model under vertical forces was 13.914 MPa and 12.793 MPa, respectively. Conclusion: Results from this study showed the platform switched abutment led to relative decrease in von Mises stress in transcortical section of bone compared to normal abutment under vertical and oblique forces in posterior mandible region.

Comparison of strain generated in bone by "platform-switched" and "non-platform-switched" implants with straight and angulated abutments under vertical and angulated load: A finite element analysis study.

Purpose: The aim of this study was to evaluate the microstrain exhibited by bone around immediately loaded, platform-switched, and non-platform-switched implants under vertical and angled loading using a finite element analysis (FEA) and also to evaluate whether platform-switched implants evoke a better response than non-platform-switched implants on a mechanical basis. Materials and Methods: Three-dimensional finite element study was undertaken to model and analyze an immediate loaded situation. FEA was chosen for this study since it is useful in determining the stress and strain around the dental implant. Bone responses to vertical and angulated loads on straight and angulated abutments (platform-switched and non-platform-switched abutments) were evaluated. Results: Non-platform-switched abutments tend to exhibit a lower tensile stress and compressive stress but higher microstrain value (conducive to higher chance of bone resorption) than platform-switched abutments. Ideal bone remodeling values of microstrain (50-3000 μϵ) were exhibited by platform-switched straight abutments under vertical load and angled load (with an abutment-implant diameter difference of 1 mm). Conclusion: In spite of the obvious advantages, the practice of immediate loading is limited due to apprehension associated with compromised bone response and a higher rate of bone loss around an immediately loaded implant. The mechanical basis for the concept of "platform switching" in immediately loaded situation is analyzed in this context. The results of this limited investigation indicated that the ideal values of microstrain (50-3000 microstrain) can be exhibited by platform switching of dental implants (with an abutment-implant diameter difference of 1 mm) and can be considered as a better alternative for prevention of crestal bone loss when compared to non-platform-switched implants.