RESUMO
Abstract The aim of this study was to evaluate the effect of different glass fiber posts (GFPs) diameters on the push-out bond strength to dentin. Forty unirradicular human teeth were endodontically treated and used for cementation of GFPs (White Post DC, FGM) with different diameters (n=10): P1 - ø 1.6 mm coronal x 0.85 mm apical; P2 - ø 1.8 mm coronal x 1.05 mm apical; P5 - ø 1.4 mm coronal x 0.65 mm apical; and PC - customized post number 0.5 with composite resin (Tetric Ceram A2, Ivoclair Vivadent). All GFPs were cemented into the root canal using a dual-curing luting composite (Variolink II, Ivoclar Vivadent). One slice (1.7 mm) of each root third of cemented GFP (cervical, middle, and apical) was submitted to push-out testing. Failure modes of all specimens were classified as: adhesive failure between resin cement and post; adhesive failure between dentin and resin cement; cohesive failure within resin cement, post or dentin; and mixed failure. The data were analyzed with two-way ANOVA and Tukey's test (a=0.05). The highest bond strength values were presented for the P2 and PC groups. There was no statistically significant difference between the GFP thirds in each group. The groups P2, P5, and PC showed predominantly adhesive failure. For P1, the most prevalent type of failure was adhesive between resin cement and post. It may be concluded that a glass fiber post that is well adapted to the root canal presents higher bond strength values, regardless of GFP third.
Resumo O objetivo neste estudo foi avaliar o impacto de diferentes diâmetros de pinos de fibra de vidro (PFVs) na resistência de união à dentina. Quarenta dentes humanos unirradiculares foram tratados endodonticamente e utilizados para cimentação de PFVs (White Post DC, FGM) com diferentes diâmetros (n=10): P1 - ø 1,6 mm coronal x 0,85 mm apical; P2 - ø 1,8 mm coronal x 1,05 mm apical; P5 - ø 1,4 mm coronal x 0,65 mm apical; e PC - pino número 0,5 individualizado com resina composta (Tetric Ceram A2, Ivoclair Vivadent). Todos os PFVs foram cimentados no canal radicular usando cimento resinoso dual (Variolink II, Ivoclar Vivadent). As raízes foram seccionadas em três secções (cervical, média e apical) e submetidas ao teste push-out. Os modos de falha de todos os espécimes foram classificados em falha adesiva entre o cimento resinoso e pino, falha adesiva entre dentina e cimento resinoso, falha coesiva no cimento resinoso, pino ou dentina e falha mista. Os dados foram analisados com ANOVA two-way e teste de Tukey (a=0,05). Os maiores valores de resistência da união foram apresentados para os grupos P2 e PC. Não houve diferença estatisticamente significante entre os terços dos PFVs cimentados na raiz para cada grupo. Os grupos P2, P5 e PC apresentaram predominantemente falha adesiva entre a dentina e o cimento resinoso. Para o grupo P1, o tipo de falha mais prevalente foi a adesiva entre cimento resinoso e pino. Pode-se concluir que o pino de fibra de vidro bem adaptado ao canal radicular apresentou os maiores valores de resistência da união, independentemente do terço dos PFVs.
Assuntos
Humanos , Técnica para Retentor Intrarradicular , Colagem Dentária , Teste de Materiais , Cimentos de Resina , Cavidade Pulpar , Dentina , VidroRESUMO
AIM: To evaluate the push-out bond strength (BS) of direct anatomic posts (DAPs) and conventional fiber posts (CFPs) cemented with different luting agents in different thirds of flared root canals. MATERIALS AND METHODS: A total of 60 human single-rooted canine teeth were transversally sectioned 16 mm from the radicular apex. After endodontic treatment, canals were flared with diamond burs. Samples were divided into six groups according to post type and luting agent: DAP and RelyX U100 (RXU); DAP and RelyX ARC (RXA); DAP and RelyX Luting 2 (RXL); CFP and RXU; CFP and RXA; CFP and RXL. Roots were sectioned transversely into six 1-mm-thick slices. The push-out test was performed and failure modes were observed. RESULTS: The DAP groups (7.23 ± 2.05) showed highest BS values (p < 0.05) when compared with CFP (5.93 ± 1.76). RelyX U100 (8.17 ± 1.70) showed higher BS values (p < 0.05) than RXA (6.46 ± 1.38), and RXL (5.10 ± 1.65) showed the lowest values. Bond strength on the apical third was statistically lower (p < 0.05) than that on the other thirds of the root canals. There was a predominance of adhesive failure for all groups. CONCLUSION: The DAPs improved retention in flared root canals, and RXU was the most effective luting agent. The apical third showed the lowest BS values. CLINICAL SIGNIFICANCE: The relining procedure of fiber posts with composite and the proper selection of luting resin cement are important for increasing bonding effectiveness in flared root canals.