Bonding effectiveness of a new universal simplified adhesive on dentin

Objectives: Multimode adhesives have been recently introduced in the market. The aim of this in vitro study was to investigate the bond strength created by a new adhesive system (AdheSE One F experimental, Ivoclar-Vivadent) with different application mode: etch-and-rinse or self-etch compared to Scotchbond Universal (3M ESPE). Microtensile bond strength test (µTBS) was performed both at baseline and after storage in artificial saliva for 6 months. The hypothesis tested was that the microtensile bond strength (µTBS) and the nanoleakage interfacial expression are not affected after 24h and 6 months in artificial saliva when the adhesive was applied either following an etch-and-rinse or a self-etch technique.

Methods: Human molars were cut to expose middle/deep dentin and assigned to one of the following bonding systems (N=10): (G1) AdheSE One F experimental self-etch mode, (G2) AdheSE One F experimental etch-and-rinse mode, (G3) Scotchbond Universal self-etch mode. Specimens were processed for µTBS test in accordance with the non-trimming technique and µTBS was performed after 24h or 6 months of storage in artificial saliva at 37°C. Data were analyzed by one-way ANOVA (p=0.05) and Tukey’s post-hoc. Additional specimens (N=3) were similarly processed and examined to assay interfacial nanoleakage expression.

Results: µTBS (MPa±SD) at time 24h: (G1) 34.1±10.4^aA, (G2) 33.3±6.1^aA, (G3) 33.7±9.9^aA; at time 6 months: (G1) 27.2±5.1^bA; (G2) 24.6±3.6^bA; (G3) 27.6±8.8^bA. At baseline all adhesives demonstrated comparable μTBS values to dentin and similar nanoleakage distribution. Storage in artificial saliva for 6 months significantly reduced the bond strength of all groups irrespective of application technique compared to immediate bond strength and increased interfacial nanoleakage expression.

Conclusion: Reductions of the bond strength and the increased nanoleakage phenomena were observed for all groups after 6 months irrespective from the application mode. Further in vivo studies are needed to assess the clinical behavior of new “multi mode” simplified adhesives.