Shear bond strength of a RMGIC for orthodontic bracket bonding to enamel.

OBJECTIVE: To evaluate the shear bond strength (SBS) of a restorative resin-modified glass ionomer cement (RMGIC) for orthodontic bracket bonding. MATERIALS AND METHODS: One hundred twenty-one human teeth were randomly divided into 11 groups (n = 11) according to the surface treatment applied (H3PO4 ± Transbond Plus (TSEP) or Scotchbond Universal (SU)), and the adhesive used (Riva LC HV (RIVA), Fuji Ortho (FUJI), and Transbond XT (TXT)). For each sample, a metal button was bonded. SBS tests were performed at 1 week and debonded specimens were observed for failure modes determination. One-way ANOVA followed by Tukey's post hoc test was used to compare SBS differences and Fisher's exact test to analyze the failure modes (p < 0.05). RESULTS: TSEP + FUJI and H3PO4 + SU + TXT showed the highest SBS values while H3PO4 + TSEP + RIVA showed the lowest value. Cohesive failure and mixed failure were found in the groups with SU and TXT and adhesive failure in the other groups. DISCUSSION/CONCLUSIONS: The bonding of orthodontic attachments to enamel could be performed with any of the three materials studied. The use of a universal adhesive in the bonding protocol could optimize the adhesion values. Clinical studies would be needed to confirm the results obtained.

Touch-cure activation by marketed universal resin luting cements of their associated primer to dentin.

PURPOSE: The aim of this study was to investigate the dentin shear bond strength (SBS) and bonding interface of three recently developed "universal" resin luting cements based on different modalities. METHODS: The dentin SBS and interfacial analysis of three recently launched "universal" resin luting cements, namely, G-Cem One, RelyX Universal and Panavia SA cement universal, were studied. All bonding protocols, including the previous use of their dedicated primer or universal adhesive in touch-cure mode or light-cure mode were performed. Variolink Esthetic LC used in conjunction with Scotchbond Universal Plus was used as a control group. For each group (n = 9), 10 specimens were tested for dentin SBS and two were examined by scanning electron microscopy. SBS were analyzed by two-way ANOVA followed by Dunnett's test. RESULTS: SBS values showed that the three "universal" resin luting cements tested exhibit different adhesive behaviors. G-Cem One with its touch-cure activated primer had a greater SBS to dentin (25.5 MPa) than that of the control group (22.1 MPa). CONCLUSION: "Universal" resin luting cements have variable efficacy when used in self-curing mode. The touch-curing mode is also of concern but may show high potential for some formulations.

Flexural properties and dentin adhesion in recently developed self-adhesive bulk-fill materials.

PURPOSE: This study investigated the flexural properties, shear bond strength (SBS) and interface to dentin of three recently developed self-adhesive bulk-fill materials. METHODS: Bars of Surefil One (SO), Cention N (CN), Activa BioActive Restorative (AB) and EQUIA Forte HT Fil (EQUIA) were tested for flexural strength and flexural modulus in self-curing and light-curing modes. In addition, SBS to dentin was tested in specimens without pretreatment and after application of universal adhesive (Scotchbond Universal). EQUIA was used as the control material. RESULTS: The flexural properties were significantly better in light-curing mode for all materials except CN. CN had the highest SBS values after universal adhesive application (33.8 MPa), and SO had the highest SBS without pretreatment (20.9 MPa). CONCLUSION: The mechanical and adhesive properties of these new materials varied widely.