Shear Bond Strength of Nanocomposites to Dentin Substrate Treated with Er:YAG Laser Followed by Two Different Bonding Systems

Abstract

Background and Aim: Preparation of tooth structure by laser systems produces a surface with different characteristics. Therefore, selecting an appropriate bonding system is necessary to achieve the maximum bond strength. The aim of this study was to compare the bond strength of Adper Single Bond 2 adhesive and Single Bond Universal to dentin prepared by bur or laser. Materials and Methods: In this experimental study, 48 third molars were collected. The enamel was abraded by wet grinding to achieve flat surfaces of dentin. Samples were divided into 4 groups. Group 1: bur preparation + Single Bond Universal adhesive, Group 2: bur preparation + Adper Single Bond 2, Group 3: Er:YAG laser preparation + Single Bond Universal adhesive and Group 4: Er:YAG laser + Adper Single Bond 2. Nanocomposites were bonded to the samples. The shear bond strength was measured. Failure mode was evaluated under a stereomicroscope. Data were analyzed using twoway ANOVA. The level of significance was considered as 0.05. Results: The shear bond strength of the laser group was significantly lower than that of bur group (P<0.001). No significant difference was observed in shear bond strength regarding the type of adhesive used (P>0.05). The failure mode in all groups was mainly mixed. Conclusion: Preparation of dentin by Er: YAG laser decreased the bond strength in comparison to diamond bur preparation. The type of adhesive did not affect the bond strength, regardless of the preparation method.

Influence of Low-Level Laser Modification and Adhesive Application Mode on the Bonding Efficiency of Universal Adhesives to Er:YAG Laser-Ablated Dentin

“…Still, the bond strength was significantly lower than that in the bur-prepared groups. 15 In a recent study, Shadman et al found a similar deterioration in the SBS of SU, used in both self-etch and etch-and rinse-modes, to dentin in Er,Cr:YSGG lased dentin groups using 4 W and 5 W output powers than bur-prepared groups, even after 500 thermocycles. 16 Although the results of these two recent studies are in accordance with the SBS of our results, none of these investigations examined the effect of using LMM after LCM.…”

“…The contradiction of these results can be attributed to the difference in laser type and parameters used. 15,16 However, the influence of LMM dentin surface modification after laser cutting on the bond strength and bond durability was not previously addressed in the literature.…”

“…[9][10][11] Although the bond strength of ER and SE adhesives to laser-ablated substrates was extensively tested in the literature, only a few studies evaluated the bonding performance of universal adhesives (UAs) to laser-ablated dentin using low or high powers. [12][13][14][15][16] Universal dental adhesives are known as "multi-mode" adhesives that can be applied in etch-and-rinse (ER), self-etch (SE), or selective-etching modes, depending on the clinical situation. Mild UAs proved their ability to achieve a significantly strong bond to dentin, which owes to the presence of functional monomers as a principal ingredient, which plays a major and unique role in chemical adhesion to dentin.…”

“…12 Furthermore, some studies have reported that LCM causes deterioration of the bond strength of UA. 15,16 However, the impact of adding LMM and/ or the acid-etching step on the bond strength before the application of UA has scarcely been tackled in literature.…”