Mechanical Fatigue Analysis of PEEK as Alternative to Zirconia for Definitive Hybrid Abutments Supporting All-Ceramic Crowns.

PURPOSE: The aim of this study was to inspect the mechanical fatigue behavior of an implant-supported restorative system using polyether ether ketone (PEEK) and yttria partially stabilized zirconia polycrystals (YZ) as materials for customized definitive implant-supported hybrid abutments, supporting two types of all-ceramic restorations: translucent zirconia (TZ) and lithium disilicate (LD) monolithic crowns. MATERIALS AND METHODS: Forty Morse taper implants were included in epoxy resin. Titanium intermediary abutments were placed, and the specimens were randomly allocated into four groups (n = 10) according to the customized hybrid abutment material (PEEK or YZ) and the monolithic crowns (TZ or LD) representing a maxillary central incisor crown. The specimens were subjected to a mechanical fatigue test (step-stress analysis) by means of an initial 200-N load for 5,000 cycles and subsequent increase of 50 N (step-size) at each 10,000 cycles, until failure occurred. The load at failure and number of cycles until failure were recorded; survival probabilities and specimen displacement were calculated for each step. The failure pattern was evaluated, and the Weibull modulus was obtained for each condition. RESULTS: Fatigue of both types of crowns was not influenced by the abutment material (LD-PEEK = LD-YZ; TZ-PEEK = TZ-YZ). In the PEEK abutment, the values obtained in the LD and TZ crowns showed no statistical difference; however, in the YZ abutment, the TZ crown presented a load at failure value that was statistically higher than that for LD. Failure pattern analysis revealed a higher prevalence of crown fracture for LD groups, while screw/implant platform fractures were shown for TZ groups. CONCLUSION: YZ and PEEK hybrid abutments promoted similar fatigue levels regardless of the crown materials, TZ crowns promoted a higher fatigue level than LD ones when associated with YZ abutments, and LD crowns promoted a similar fatigue level to TZ ones when associated with PEEK custom abutments. Higher prevalence of crown fractures was shown for LD and screw/implant platform fractures for TZ groups.

Collagen vs expanded polytetrafluorethylene membranes during guided-bone regeneration simultaneous with implant placement: a systematic review / Membranas de colágeno vs politetrafluoretileno expandido para regeneração óssea guiada simultânea à colocação de implante: uma revisão sistemática

Purpose: This systematic review evaluated the influence of the membrane type (resorbable collagen or non-resorbable expanded polytetrafluorethylene; e-PTFE) on the guidedbone regeneration associated to implant placement. Methods: Any type of clinical study or literature review was searched at MEDLINE/PubMed and Cochrane databases. Two independent reviewers screened titles/abstracts of articles and the full-text of potentially eligible studies. When data was available, pairwise meta-analysis was performed using random statistical model. Results: Nine studies met the inclusion criteria, considering 685 implants in 360 patients. Vertical bone regeneration did not differ with the use of the two membranes in 8 of the 9 studies included. Meta-analysis did not show either greater vertical bone gain or vertical bone loss after regeneration with any of the membranes. The results have shown a tendency of higher bone gain in horizontal guided-bone regeneration with nonresorbable e-PTFE membranes (reported by 2 of 3 studies). All studies clearly showed that both membranes were effective in increase bone volume. There was no clear tendency of any of the two membranes in cause more complications. Conclusion: resorbable collagen and nonresorbable e-PTFE membranes are similarly effective in vertical guided-bone regeneration; however, horizontal guided-bone regeneration seems to benefit with the use of non-resorbable ones. Both membranes showed to be effective in guided-bone regeneration and similar in regards to complications(AU)

Objetivo: Esta revisão sistemática avaliou a influência do tipo de membrana (colágeno reabsorvível ou politetrafluoretileno expandido não reabsorvível; e-PTFE) na regeneração óssea guia associada à colocação do implante. Métodos: Qualquer tipo de estudo clínico ou revisão de literatura foi pesquisada nas bases de dados MEDLINE / PubMed e Cochrane. Dois revisores independentes examinaram títulos / resumos de artigos e o texto completo de estudos potencialmente elegíveis. Quando os dados estavam disponíveis, a meta-análise pareada foi realizada usando modelo estatístico aleatório. Resultados: Nove estudos preencheram os critérios de inclusão, considerando 685 implantes em 360 pacientes. A regeneração óssea vertical não diferiu com o uso das duas membranas em 8 dos 9 estudos incluídos. Meta-análise não mostrou maior ganho ósseo vertical ou perda óssea vertical após a regeneração com qualquer uma das membranas. Os resultados mostraram uma tendência de maior ganho ósseo na regeneração óssea guiada horizontal com membranas de e-PTFE não reabsorvíveis (relatadas por 2 de 3 estudos). Todos os estudos mostraram claramente que ambas as membranas foram eficazes no aumento do volume ósseo. Não houve uma tendência clara de qualquer uma das duas membranas em causar mais complicações. Conclusão: o colágeno reabsorvível e as membranas não-reabsorvíveis de PTFE-e são igualmente eficazes na regeneração óssea guiada vertical; no entanto, a regeneração óssea guiada horizontal parece se beneficiar com o uso das membranas não reabsorvíveis. Ambas as membranas mostraram-se eficazes na regeneração óssea guiada e similares em relação às complicações(AU)

Aumento do rebordo alveolar maxilar usando osso autógeno associado ao osso heterógeno particulado ­ relato de caso / Maxillary alveolar ridge augmentation using autogenous and heterogeneous bone grafts ­ case report

O objetivo deste relato de caso foi demonstrar que o uso de osso autógeno associado ao enxerto alógeno e membranas de lenta reabsorção é uma alternativa confiável em procedimentos de regeneração óssea alveolar. Uma paciente do sexo feminino, com 47 anos de idade, foi encaminhada para reabilitação com implantes dentários em região anterior de maxila. A espessura de osso na região era delgada, com menos de 2 mm. O aumento de tecido foi realizado por meio de regeneração óssea tecidual. Os blocos de osso autógeno foram coletados do ângulo da mandíbula e modelados conforme o sítio receptor. Os blocos foram fixados com parafusos e os espaços foram preenchidos com osso autógeno particulado associado ao enxerto alógeno (Bio Oss®). Uma membrana de lenta reabsorção (Bio Guide®) foi utilizada para cobrir o leito receptor. A ferida foi coberta usando o tecido mucoperiosteal. Aos seis meses, um novo exame radiográfico foi solicitado para planejar os implantes a serem instalados e verificou-se aumento entre 7,53 mm até 10,73 mm. Nenhuma exposição foi observada. Após isso, os implantes foram instalados com auxílio de guia cirúrgico. Os acompanhamentos pós-cirúrgicos revelaram estabilidade dos implantes com excelente osseointegração e área satisfatoriamente reconstruída. O uso de enxertos autógenos continua sendo alternativa adequada de regenerações, especialmente quando associadas aos ossos alógenos e membranas de lenta reabsorção (AU).

The aim of this case report was to demonstrate that the use of autogenous bone graft associated with deproteinized bovine bone and slow absorption membrane is a reliable alternative for maxillary alveolar bone regeneration. Female patient, 47-year-old was referred for implant placement in the maxillary anterior region. The alveolar bone width at the region was thin, with less than 2 mm. The tissue augmentation was accomplished using bone regeneration. The autogenous bone blocks were collected from the mandible angle and shaped according to the receiving site. The blocks were fixed with screws and gaps filled with a mixture of particulate autogenous bone and deproteinized bovine bone (Bio-Oss®). A slow absorption membrane (Bio-Guide®) was used to cover all regenerated site. The wound was closed using a vestibular mucoperiosteal flap. At 6 months, a new radiographic exam was requested to plan the implants to be placed and it was verified new bone width, with measures between 7.53 mm and 10.73 mm. No exposure was observed. After that, the implants were placed by the aid of a surgical guide. The postoperative follow-up revealed that the implants were stable with excellent osseointegration and the surgical area was satisfactorily reconstructed. The use of autogenous bone grafts is still an adequate alternative to alveolar regeneration, especially when associated to deproteinized bovine bone graft and slow reabsorption membrane (AU).