Influence of surface moisture condition on the bond strength to dentin of etch-and-rinse adhesive systems

Abstract

Aim: To evaluate the immediate microtensile bond strength (µTBS) of three two-step etch-andrinse adhesive systems applied under different dentin surface moisture conditions. Methods: Class V cavities were prepared in seventy-two bovine incisors. Each tooth was randomly allocated into three groups, according to the adhesive system used: Single Bond 2 (SB), Prime & Bond 2.1 (PB) and XP Bond (XPB). Each group was divided in three subgroups, according to the dentin moisture condition: over-wet, moist and dry (n=8). For the moist subgroups the adhesive was applied as to the manufacturer's instructions; for the over-wet ones, without drying the cavity after the rinsing procedure; and for the dry subgroups, drying the surface for 20 s. The teeth were restored with Filtek Z-250 and stored in distilled water (24 h); next, each restoration was sectioned in beam-shaped specimens which were stored for 24 h at 37 °C. Each specimen was submitted to µTBS test (EMIC), and data were analyzed using two-way ANOVA and Tukey test (p<0.05). Results: There was a statistically significant interaction between the adhesive system type and the dentin surface moisture condition (p=0.003). SB and XPB presented higher bond strength in the moist dentin condition, and PB showed high µTBS values in the dry substrate. Conclusions: The moisture condition influenced the bond strength between the adhesives and dentin. SB performed better in the moist condition, whereas PB and XPB showed satisfactory bond strength in the moist and in the dry substrates. The over-wet dentin condition only impaired bond strength to SB and XPB.

Effect of dentin moisture and bonding strategies on micro-tensile bond strength using two chemically different universal adhesives

“…This higher water content in P&BU is linked to a increased water content on the dentin surface (wet), this might explain why P&BU has a lower binding strength value than SBU 30,35 . The previous results agree with the study done by Münchow et al 36 which showed that Prime & Bond 2.1 having the same amount of water content in its composition as P&BU had decreased micro-tensile bond strength when used on wet dentin surface.…”

“…These outcomes could be attributed to the fact that over-drying of the dentin surface collapsed the fibrils of the collagen matrix, limiting penetration of monomers inside the dentinal collagen network 36 . In wet dentin surface, it's possible that too much water diluted the adhesive ingredient, making the hybrid layer porous 36 .…”

Cytotoxicity of contemporary resin‐based dental materials in contact with dentin

“…For CLA, a similar behavior was observed: lower cell viability was observed when dentin was present. A possible explanation relies on the fact that dentin moisture could have affected the degree of C=C conversion (29), especially due to the hydrophobic nature of Variolink II components. The reduced C=C conversion could increase the release of unreacted monomers and, consequently, the cytotoxicity exerted on HaCaT cells.…”

Bond strength of a universal bonding agent and other contemporary dental adhesives applied on enamel, dentin, composite, and porcelain

“…Adhesive bonding in dentistry is a process dependent on several factors, such as the type of substrate [1], type of adhesive substance(s) [2], humidity of the environment [3,4], and operator's ability in performing the bonding procedure [5]. With regard to the dental substrates, adhesive procedures are usually performed to achieve bond to dental enamel and dentin.…”