Microtensile Bond Strength of Adhesive Systems in Different Dentin Regions on a Class II Cavity Configuration

Abstract

The aim of this study was to evaluate microtensile bond strength (µTBS) of self-etch and etch-and-rinse adhesives systems compared in different dentin regions (central-CD or proximal-PD) in a class II cavity configuration. A class II (mesial-oclusal-distal) cavity configuration was simulated on 20 extracted human third-molars (4 mm wide/3 mm deep). Etch-and-rinse adhesive (Scotchbond Multi Purpose, n=5, SBMP and Optibond FL, n=5, OPFL) and self-etch adhesives (Clearfil SE Bond, n=5, CSE and Optibond XTR, n=5, OPXTR) were applied. Class II restorations were performed by incremental technique and photo-activated (Bluephase/G2). Samples were sectioned to beam shape (1 mm² cross-section), placed on Geraldeli's device for µTBS test (0.5 mm/min cross-head speed). Fracture patterns were analyzed on stereomicroscope and classified as cohesive-resin, adhesive, mixed/resin or mixed/dentin. Samples (n=4) were prepared for scanning electron microscope observation. Data were submitted to one-way ANOVA with Split-Plot arrangement and Tukey's test (α=0.05). There were no statistically significant differences among SBMP, OPFL, CSE and OPXTR on CD (p>0.05). However, on PD for SBMP and OPFL, µTBS values were significantly lower compared to CSE and OPXTR (p<0.05). In all groups, mixed failure pattern was more frequently observed, except for SBMP/CD (adhesive). In class II type cavity configuration, PD location negatively influenced bond strength of etch-and-rinse adhesive systems. Opposite to self-etching adhesives, which presented higher bond strength values compared to etch-and-rinse adhesives in PD.

Assessment of Bonding Effectiveness of Adhesive Materials to Tooth Structure using Bond Strength Test Methods: A Review of Literature

“…5 ). The resulting slabs are composed of an upper half of resin composite and a lower half of dentin, using an ultrafine diamond bur; the cross-sectioned area at the bonded interface should be reduced to form an hour-glass shape to ensure maximum stress development at that region [ 25 ].…”

“…Pashley et al ., [ 53 ] examined the shear bond strengths to superficial, intermediate, and deep dentin with four dentin bonding systems and confirmed higher bond strengths in superficial dentin and progressively lower bond strengths in deep dentin. This was attributed either to differences in chemical composition of tested adhesives or regional differences in wetness (dentin permeability) [ 25 ]. Shear bond strength results were known to decrease with increased dentin depth and permeability [ 54 ].…”

Does Adhesive Layer Thickness and Tag Length Influence Short/Long-Term Bond Strength of Universal Adhesive Systems? An In-Vitro Study

“…The SEM is an effective analytical test to evaluate the resin-dentin interfaces, but with some limitations such as the artefacts (fracture or gap) at the dentin-adhesive interface caused by the different preparation steps [7]. However, one of the limitations of this study is that the bond strength of the tested adhesives was evaluated in vitro by the SBS test on flat dentin surfaces; this neglects an important clinical factor, which is the effect of C-factor [29]. In this study, the samples were tested using the SBS test because it is easier to prepare and no sectioning preparations (stick of 1 mm 2 ) are required to perform the experiment.…”

“…All the measures for the evaluation of the tag penetration were performed in correspondence of the center of the composite-cylinder in order to prevent the effect of tubules position (density and diameter). Tubules diameters and density increase from the dentinenamel junction to central dentin area [29].…”