Bond strength of two total-etching bonding systems on caries-affected and sound primary teeth dentin

Micro-shear Bond Strength of an Alternative Self-etch Application of "No Wait" Universal Adhesive to Caries-affected and Sound Dentin in Permanent and Primary Teeth

OBJECTIVE

This study aimed to compare the micro-shear bond strength (μSBS) of caries-affected dentin (CAD) and sound dentin (SoD) in primary and permanent teeth using an alternative self-etch application of "no wait" universal adhesive.

METHODS AND MATERIALS

Flat midcoronal dentin surfaces from 72 permanent third molars and 72 second primary molars were distributed randomly into 12 groups according to the substrate SoD and artificially-created CAD (pH cycling for 14 days) and the adhesive system (GLUMA Bond5, a two-step etch & rinse adhesive, GLUMA Bond, a one-step self-etch adhesive, and Tokuyama Universal Bond, a one-step self-etch adhesive) (n=12). Bonded dentin resin discs were put through micro-shear bond strength testing after 10,000 thermocycles. The results were evaluated using two-way ANOVA and the Bonferroni test with a significance level of α = 0.05.

RESULTS

When compared to SoD, the etch & rinse system's test results on artificially created CAD showed a statistically significant poorer bonding performance in both permanent and primary teeth in all groups (p<0.05). While the bond strengths of permanent teeth using total-etch adhesive on sound dentin were statistically significantly higher than those using Tokuyama Universal Bond adhesive (p<0.05), there was no significant difference in sound dentin in primary teeth (p>0.05).

CONCLUSIONS

The etch & rinse system performed the poorest of all adhesive systems on CAD. The Tokuyama Universal Bond's adhesive strength was similar in SoD and CAD on primary teeth. The use of Tokuyama Universal Adhesives can speed up restorative treatment in pediatric dentistry.

Assessment of Caries-Affected Dentin Adhesive Interface Treated with Contemporary Conditioning Techniques

Objective: The aim of this study was to assess shear bond strength (SBS) and failure analysis of adhesion of composite resin (CR) to caries-affected dentin (CAD) pretreated with the Er,Cr:YSGG (ECY) laser, photodynamic therapy (PDT), and etch and rinse (ER) used for cavity disinfection. Materials and methods: Methods used in this study included scanning electron microscopy (SEM), SBS analysis, failure analysis, and digital microscopy. The methods were adopted to assess bond integrity, CAD interface, smear layer, and hybridization. Thirty human third molars assessed clinically and having scores of 4 and 5 based on International Caries Detection and Assessment System (ICDAS) criteria were inspected. Infected dentin was removed. Dentin that was hard and stained pink was categorized as CAD. Ten samples were used in each group for pretreatment of CAD. Ten samples of healthy dentin [sound dentin (SD)] were collected separately and taken as controls. Samples were divided into the following groups: group 1: SD+ER; group 2: CAD+ER; group 3: CAD+ECY; and group 4: CAD+PDT after the pretreatment bonding agent was applied and the restorative procedure was performed using CR. Results: CAD conditioned with PDT before bonding to CR demonstrated the lowest SBS values (11.22 ± 0.77 MPa), whereas the highest SBS values were observed in the SD surface treated with ER (18.25 ± 1.22 MPa). In CAD and SD pretreated with ER, majority of failure modes were cohesive failure and admixed failure, whereas in CAD pretreated with PDT and the ECY laser, the adhesive failure mode was pertinent. Conclusions: The use of the ECY laser and PDT on CAD for cavity disinfection does not have potential for application in clinical settings as it decreases bond integrity of CR. Moreover, the ER pretreatment method for CAD and SD remains the gold standard.

Effect of adhesive mode and chlorhexidine on microtensile strength of universal bonding agent to sound and caries-affected dentins

Objective:

The main objective of this study is to assess the effect of the adhesive mode and chlorhexidine (CHX) on the microtensile strength of a universal bonding agent to sound and caries-affected dentins.

Materials and Methods:

Six intact third molars and six decayed third molars were sectioned to obtain two middle dentin specimens per tooth. Prime and Bond Elect Universal (Dentsply) was applied to specimens in two different modes: Etch-and-rinse (ER, phosphoric acid for 15s) and self-etch (SE, no phosphoric acid). 2% CHX (Cavity Cleanser, Bisco) was applied to both dentins for 30 s. Specimens were randomly assigned into eight groups (n = 3) according to the treatments applied to sound and caries-affected dentins: SE; ER; SE + CHX; and ER + CHX. All specimens were restored with TPH Spectra High Viscosity (Dentsply) composite resin and sectioned to obtain specimens of 0.8 ± 0.1 mm². The microtensile bond strength test was conducted at 1 mm/min. The data were statistically analyzed by ANOVA and multiple comparisons’ test (α = 0.05).

Results:

There was no significant difference between sound dentin and caries-affected dentin (P = 0.132). The highest bond strength was obtained with the application of the ER (31.81MPa). SE + CHX promoted the lowest bond strength with no statistical difference to ER + CHX (P > 0.05).

Conclusions:

ER mode for the universal bonding agent yielded the highest bond strength to sound and caries-affected dentins. CHX reduced the bond strength to both dentins regardless the application of phosphoric acid.

Clinical Significance:

The universal bonding agent increased the bond strength to sound and caries-affected dentins when applied by the ER mode.