Do resin cements influence the cuspal deflection of teeth restored with composite resin inlays?

The aim of this study was to evaluate the influence of different resin cements on the cuspal deflection of endodontically treated teeth restored with composite resin inlays. Sixty upper premolars were randomly divided into five groups (n=12): 1 - sound teeth; 2 - cavity; 3 - Rely X ARC; 4 - RelyX Unicem; 5 - SeT. The teeth from groups 2, 3, 4 and 5 received a MOD preparation and endodontic treatment. Impressions were made with vinyl polysiloxane and poured using type IV die stone in groups 3, 4 and 5. Inlays with composite resin were built over each cast and luted with the resin cements. A 200 N load was applied on the occlusal surface, and cuspal deflection was measured using a micrometer. After 24 h, cuspal deflection was measured again using a 300 N load. The Student t-test showed that there was no statistically significant difference between the 200 N and 300 N occlusal loads only for the sound teeth group (p = 0.389) and the RelyX ARC group (p = 0.188). ANOVA and Tukey'test showed that the sound teeth had the lowest mean cuspal deflection, differing statistically from the other groups (p<0.05). The highest cuspal deflections were obtained in the SeT group and the cavity group, with no statistical difference between them. Intermediate values were obtained in RelyX ARC group and RelyX Unicem group, which differed statistically. The self-adhesive resin cements RelyX Unicem and SeT showed less capacity to maintain the stiffness of the tooth/restoration complex than the conventional resin cement RelyX ARC.

Do resin cements influence the cuspal deflection of teeth restored with composite resin inlays?

The aim of this study was to evaluate the influence of different resin cements on the cuspal deflection of endodontically treated teeth restored with composite resin inlays. Sixty upper premolars were randomly divided into five groups (n=12): 1 - sound teeth; 2 - cavity; 3 - Rely X ARC; 4 - RelyX Unicem; 5 - SeT. The teeth from groups 2, 3, 4 and 5 received a MOD preparation and endodontic treatment. Impressions were made with vinyl polysiloxane and poured using type IV die stone in groups 3, 4 and 5. Inlays with composite resin were built over each cast and luted with the resin cements. A 200 N load was applied on the occlusal surface, and cuspal deflection was measured using a micrometer. After 24 h, cuspal deflection was measured again using a 300 N load. The Student t-test showed that there was no statistically significant difference between the 200 N and 300 N occlusal loads only for the sound teeth group (p = 0.389) and the RelyX ARC group (p = 0.188). ANOVA and Tukey'test showed that the sound teeth had the lowest mean cuspal deflection, differing statistically from the other groups (p<0.05). The highest cuspal deflections were obtained in the SeT group and the cavity group, with no statistical difference between them. Intermediate values were obtained in RelyX ARC group and RelyX Unicem group, which differed statistically. The self-adhesive resin cements RelyX Unicem and SeT showed less capacity to maintain the stiffness of the tooth/restoration complex than the conventional resin cement RelyX ARC.

O objetivo deste estudo foi avaliar a influencia de diferentes cimentos resinosos na deflexao de cuspides de dentes tratados endodonticamente e restaurados com inlays em resina composta. Sessenta pre-molares foram divididos aleatoriamente em cinco grupos (n=12): grupo 1 - dentes higidos; 2 - cavidade; 3 - Rely X ARC; 4 - RelyX Unicem; 5 - SeT. Os dentes dos grupos 2, 3, 4 e 5 receberam preparos cavitarios MOD e tratamento endodontico. Foram realizadas moldagens com silicone por adicao nos grupos 3, 4 e 5, seguido de vazamento de gesso tipo IV. Inlays em resina composta foram construidas sobre os modelos de gesso, sendo as inlays cimentadas com os cimentos resinosos. Uma carga de 200 N foi aplicada na face oclusal, e a deflexao de cuspide foi medida usando um micrometro. Apos 24 h, a deflexao de cuspide foi medida novamente sob carga de 300 N. De acordo com o teste t-Student, nao houve diferenca estatistica na deflexao de cuspides apenas para o grupo dos dentes higidos (p = 0.389) e o grupo do RelyX ARC (p = 0.188) quando comparada as duas cargas. De acordo com ANOVA e o tese de Tukey, os dentes higidos tiveram a menor media de deflexao de cuspides, diferindo estatisticamente dos outros grupos (p<0.05). A maior deflexao de cuspides foi obtida com o grupo SeT e o grupo cavidades, nao diferindo estatisticamente entre si. Valores intermediarios foram obtidos para os grupos RelyX ARC e RelyX Unicem, diferindo estatisticamente entre si. Os cimentos resinosos autoadesivos RelyX Unicem e SeT mostraram menor capacidade de manter a rigidez do complexo dente/restauracao em comparacao com o cimento resinoso RelyX ARC.

Can ultrasound application influence the bond strength of self-adhesive resin cements to dentin?

The aim of this study was to evaluate the influence of ultrasound application on the bond strength of self-adhesives resin cements to dentin. Twenty-four third molars were randomly divided into 4 groups (n = 6/group): G1 - RelyX Unicem; G2 - Maxcem Elite; G3 - RelyX Unicem and ultrasound application; G4 - Marcem Elite and ultrasound application. Composite resin blocks were luted to flat dentin with a load of 500 g for 2 min, followed by light polymerization in G1 and G2. In G3 and G4, the ultrasound device was applied for 20 s on the composite resin block, followed by 500 g load for 1 min and 40 s, and light polymerization. After storage in distilled water at 37 degrees C for 24 h, six tooth/resin sets were cut parallel to the long axis of the tooth, in the x and y directions, with a cross section area of -0.80 mm2. Twenty-four specimens were obtained for each group and submitted to microtensile bond strength (microTBS) testing in a universal testing machine at 0.5 mm/min crosshead speed. According to two-way ANOVA, resin cement (p = 0.000) and cementation method (p = 0.002) were significant. Interaction was not significant (p = 0.676). According to Student's-t test (alpha = 0.05), the microTBS mean with ultrasound application (13.74 MPa) was statistically higher than without it (10.57 MPa). The microTBS mean of RelyX Unicem (13.95 MPa) was statistically higher than Maxcem Elite (10.36 MPa). The ultrasound application increased the microTBS of the RelyX Unicem and Maxcem Elite to dentin.