Influence of different catilever extensions and glass or polyamaramid reinforcement fibers on fracture strength of implant-supported temporary

Abstract

In long-term oral rehabilitation treatments, resistance of provisional crowns is a very important factor, especially in cases of an extensive edentulous distal space. The aim of this laboratorial study was to evaluate an acrylic resin cantilever-type prosthesis regarding the flexural strength of its in-balance portion as a function of its extension variation and reinforcement by two types of fibers (glass and polyaramid), considering that literature is not conclusive on this subject. Each specimen was composed by 3 total crowns at its mesial portion, each one attached to an implant component (abutment), while the distal portion (cantilever) had two crowns. Each specimen was constructed by injecting acrylic resin into a two-part silicone matrix placed on a metallic base. In each specimen, the crowns were fabricated with either acrylic resin (control group) or acrylic resin reinforced by glass (Fibrante, Angelus) or polyaramide (Kevlar 49, Du Pont) fibers. Compression load was applied on the cantilever, in a point located 7, 14 or 21 mm from the distal surface of the nearest crown with abutment, to simulate different extensions. The specimen was fixed on the metallic base and the force was applied until fracture in a universal test machine. Each one of the 9 sub-groups was composed by 10 specimens. Flexural strength means (in kgf) for the distances of 7, 14 and 21 mm were, respectively, 28.07, 8.27 and 6.39 for control group, 31.89, 9.18 and 5.16 for Kevlar 49 and 30.90, 9.31 and 6.86 for Fibrante. Data analysis ANOVA showed statistically significant difference (p<0.05) only regarding cantilever extension. Tukey's test detected significantly higher flexural strength for the 7 mm-distance, followed by 14 and 21 mm. Fracture was complete only on specimens of non-reinforced groups.

Effect of polyester fiber reinforcement on the mechanical properties of interim fixed partial dentures

“…The bis-acrylic provisional material was the strongest (flexural strength, compressive strength, degree of deflection, and elastic modulus), followed by heat-polymerized PMMA and cold-polymerized PMMA. The study was in accordance with many different studies regarding polymer reinforcement with fibers (Colán Guzmán et al, 2008, Didia et al, 2010, Eisenburger et al, 2008, Fahmy and Sharawi, 2009, Geerts et al, 2008, Hamaza et al, 2004; Kamble and Parkhedkar, 2012, Uzun et al, 1999, Zortuk et al, 2008). This study also correlated with many previous studies of nonreinforced interim FPDs showing that polyester fibers significantly improved the mechanical properties of the material (Haselton et al, 2002, Nejatidanesh et al, 2006, Rosentritt et al, 2004).…”

Fixed partial dentures in an up to 8-year follow-up

“…The use of ultrahigh molecular weight polyethylene (UHMWP) fibers is based on the improvement of the composite resin mechanical properties and behaviour 6,19,24 . This improvement depends on the fiber direction and pre-treatment.…”

“…Over the past decades, new developments in resin technology and patient demand for toothcolored restorations led to an increased use of resin-bonded fiber-reinforced fixed partial dentures (inlay FPDs) to replace a single missing tooth, as reported in several studies 1 , 4 , 13 , 24 , 31 . The use of ultrahigh molecular weight polyethylene (UHMWP) fibers is based on the improvement of the composite resin mechanical properties and behaviour 6 , 19 , 24 . This improvement depends on the fiber direction and pre-treatment.…”

Avaliação de dois diferentes planejamentos de próteses totais fixas implantossuportadas, comparando as técnicas de fabricação das infraestruturas: tecnologia <i>CAD-CAM</i>, fundição convencional e barra articulada

“…Em contrapartida, é percebido menor volume de artigos comparando outros problemas biomecânicos destas próteses mais extensas, como a perda de torque dos parafusos protéticos e a fratura dos componentes da prótese. Este tipo de pesquisa é feito mais comumente em próteses unitárias ou com extensões menores, além de muitas vezes só avaliarem os pilares e/ou infraestruturas sem o recobrimento estético final (Hecker e Eckert, 2003;Moris, 2011;Pedroso e Silva, 2012;Colán Guzmán et al, 2008;Faenza et al, 2013;Chong et al, 2014).…”

“…Os autores concluíram que quanto maior a extensão do cantilever menor é a força necessária para induzir uma fratura neste tipo de infraestrutura. Em outro estudo, autores concluem que a resistência flexural de próteses temporárias implantossuportadas aumenta com a redução do comprimento cantilever(Colán Guzmán et al, 2008). Em outro estudo comparando infraestruturas de zircônia com cantilever, os autores concluíram que quando o carregamento ocorreu à distância de 7mm do último implante, as próteses precisaram de maior quantidade de carga para fraturar do que quando aplicada carga a 10mm(Chong et al, 2014).…”