The Effect of Dental Enamel Pre-Etching for Self-Etching Adhesives According to their Primer pH: An In Vitro Bond Strength, Etching Pattern and Adhesive Failure Evaluation

Abstract

Dental enamel pre-etching before the application of a self-etching adhesive (SEA) has different effects depending on the pH of the adhesive acidic monomer, being not always beneficial. This study aimed to evaluate the shear bond strength (SBS), etching pattern, and fracture type of different acidity SEAs, with and without previous phosphoric acid etching. One-hundred-sixty bovine incisors were subjected to SBS testing with the following adhesive systems: Adper-Prompt-L-Pop (APLP) (strong acidity), Futurabond NR (FB), AdheSE One F (AD) (intermediary acidity) and Clearfil SE (CSE) (mild acidity), with and without previous phosphoric acid etching. Results were evaluated applying both ANOVA and Tukey’s test. Besides, forty bovine incisors were used to assess etching patterns using scanning-electron-microscopy (SEM). Adhesive failure was evaluated, classifying bond failure as one of five types. SBS averages were (MPa): without pre-etching: APLP (20.61±11.84), CSE (17.29±10.16), FB (11.44±6.99), AD (7.88±4.85) and with pre-etching: APLP (16.17±9.68), CSE (25.96±11.75), FB (20.12±9.39), AD (14,28±9.42). Different enamel etching patterns were observed depending on each SEA’s pH and whether the surface was pre-etched. Most fracture failures were adhesive type. Less than 10 % were cohesive type. SBS improves when mild and intermediary strength SEAs are pre-etched. However, it decreases when strong SEAs are pre-etched.

Impact of Different Etching Strategies on Margin Integrity of Conservative Composite Restorations in Demineralized Enamel

“…This may explain the superior margin integrity of composite restorations after pre-etching both sound and demineralized enamel with phosphoric acid. A recent study found that the effect of enamel pre-etching with phosphoric acid on the bond strength of self-etch adhesives differs according to the primer pH [ 38 ]. In their study, the authors observed a significant increase in enamel bond strength after pre-etching enamel with phosphoric acid when ‘mild’ or ‘intermediately strong’ adhesives were subsequently applied, but not when a ‘strong’, i.e., highly acidic, adhesive was used [ 38 ].…”

“…A recent study found that the effect of enamel pre-etching with phosphoric acid on the bond strength of self-etch adhesives differs according to the primer pH [ 38 ]. In their study, the authors observed a significant increase in enamel bond strength after pre-etching enamel with phosphoric acid when ‘mild’ or ‘intermediately strong’ adhesives were subsequently applied, but not when a ‘strong’, i.e., highly acidic, adhesive was used [ 38 ]. The adhesives used in the present study, iBond Self Etch (pH = 1.6–1.8) and Clearfil SE Bond (pH = 2.0), which benefited substantially from enamel pre-etching, fall into the group of ‘intermediately strong’ and ‘mild’ adhesives, respectively [ 39 ].…”

Assessment of enamel surface roughness and hardness with metal and ceramic orthodontic brackets using different etching and adhesive systems: An in vitro study

“…The trend of self-etch (SE) surface treatment requires less chair time owing to fewer clinical application steps ( Horiuchi et al, 2009 ). SE combines the etching and priming stages using an acidic monomer, eliminating the need for separate etching, rinsing, and drying steps ( Horiuchi et al, 2009 , Nicolas-Silvente et al, 2020 ).…”