Influence of the mode of application of universal adhesive systems on adhesive properties to fluorotic enamel

Abstract

The objective of this study is to compare the resin-enamel bond strength (mμSBS), in-situ degree of conversion (DC), and the enamel-etching pattern (SEM/EDX) of universal adhesive systems when applied to sound and fluorotic enamel. Ninety-eight human molars were sectioned into 4 parts and divided into 24 groups according to 1) enamel surface (sound or fluorotic enamel), 2) adhesive system (Clearfil Universal Bond [CUB], Futurabond U [FBU], iBond Universal [IBU], and Scotchbond Universal [SBU]), and 3) application mode (etch-andrinse [ER], active self-etch [Active-SE], and passive self-etch [Passive-SE]). Specimens were stored at 37 °C, for 24 hours and tested at 1.0 mm/ min (μSBS). Enamel-resin interfaces were evaluated for in-situ DC. The enamel-etching pattern was evaluated under a SEM/EDX. Data from mμSBS and in-situ DC was analyzed using a three-way ANOVA and Tukey's test at 5 % level of significance. For all adhesives, the ER resulted in a statistically significant higher mean mμSBS than the passive-SE in both substrates (p < 0.001). For all adhesives, active-SE resulted in mean mμSBS (p > 0.31) and in-situ DC (p > 0.45) that were statistically similar to those obtained with the ERs in both substrates. A statistically significant, higher mean mμSBS and in-situ DC were obtained in sound enamel (p < 0.001) than in fluorotic enamel. In general, SBU showed higher mean values for mμSBS and in-situ DC compared to those of CUB and IBU (p < 0.001). ER and active-SE showed the deepest enamel-etching pattern in both substrates. A higher amount of fluor was observed in fluorotic enamel. The active application of universal adhesives in the SE-mode may be a viable alternative to increase the adhesive properties in sound and fluorotic enamel.

Effectiveness of sodium hypochlorite treatment on the bonding of four adhesive systems to fluorotic enamel

“…In the study, Waidyasekera et al found the total-etch system had greater adhesion strength than the self-etch system 23) . Cardenas et al showed the etch and rinse mode resulted in higher mean μSBS than the passive self-etch groups and more pronounced etching pattern than the self-etch mode in sound and fluorotic enamel for all universal adhesives 17) . So, we applied phosphoric acid to all samples to acquire good results and eliminate the interference caused by the phosphoric acid as a variable.…”

“…Although there were conclusions that good bonding results were obtained on hypomineralized and normal enamel after treatment of 5.25% NaOCl 11,14,15) , an article reported that NaOCl pretreatment had no statistical significance on the bonding strength of Adper™ Single Bond 2 adhesive before acid etching 16) . In recent years, several studies have found that the adhesion strength of fluorotic enamel was also related to adhesive systems 2,17) . Therefore, we speculate that NaOCl has different effects on enamel adhesion with different bonding systems.…”

Bond Strength Comparison Among 10-MDP-Containing and Non-10-MDP-Containing Adhesives in Different Degrees of Dental Fluorosis

“…In general, research on changes and alterations in dental adhesion focus on studies comparing healthy tooth surfaces against fluorosed tooth surfaces (27,(31)(32)(33)(34), surfaces such as zirconia (35), some more between fluorotic dentin surfaces (36,37). In the study conducted by Liu et al (38), it was determined that the use of the total etch adhesive system in different degrees of dental fluorosis resulted in improving the bond strength of enamel with mild fluorosis.…”

Update on Enamel Bonding Strategies

“…For example, doublelayer application of universal adhesives was reported to increase the enamel bond strength (106, 107), but not effective for 2-SEA (106). The active application of universal adhesives in the SE mode may be an alternative to increase the adhesive properties in the enamel (108,109). However, the active application of universal adhesives in the ER mode exhibited significantly lower bonding strength (110).…”