Bovine Dentin as a Substitute for Human Dentin: Bond Strength Tests on Sound and Eroded Substrate

<b>Objectives:</b> Investigating and comparing the micro-tensile bond strength (µTBS) of etch-and-rinse (ER) or self-etch (SE) adhesives on sound (s) and eroded (e) human (H) and bovine (B) dentin. <b>Methods:</b> Twenty-four human and bovine teeth were divided into eight groups (<i>n</i> = 6) and coronally ground down, exposing their dentin. Two groups of human (HeER + HeSE) and bovine teeth (BeER + BeSE) were subjected to erosive challenges (citric acid (pH 2.7), 10 × 2 min per day for five days, and stored in artificial saliva). Groups HsER + HeER and BsER + BeER were treated with an etch-and-rinse adhesive (OptiBond FL), and groups HsSE + HeSE and BsSE + BeSE were treated with a self-etch adhesive (OptiBond All-in-One), followed by buildups with a composite restorative material. After seven days of storage in tap water, µTBS was determined and failure type analysis was performed. Data were evaluated using two-way ANOVA and Tukey's post hoc tests at a level of significance of α = 0.05. <b>Results:</b> Using etch-and-rinse adhesive, sound human dentin (HsER) showed the significantly highest µTBS (<i>p</i> < 0.05) compared to eroded human (HeER) and sound and eroded bovine dentin (BsER + BeER). For sound human and bovine specimens (HsSE + BsSE), there was no significant difference (<i>p</i> ≥ 0.05) in µTBS when self-etch adhesive was applied, as well as in the eroded specimens (HeSE + BeSE). <b>Conclusions:</b> Within the limitations of this study, it can be concluded that for the etch-and-rinse approach, it is not recommended to substitute human dentin with bovine dentin. When using the specific self-etch adhesive used in the present study, bovine dentin can be used to substitute human dentin, as they showed comparable µTBS.