Efficacy of a 10‐ <scp>MDP</scp> ‐Containing Cleaner on the Bond Strength to Saliva Contaminated Dentin

OBJECTIVES: To evaluate the effect of saliva contamination and a 10-MDP-containing cleaner (Katana Cleaner; Kuraray Noritake, Japan) on the shear bond strength (SBS) of an ultra-mild universal adhesive applied in self-etch mode to human dentin. MATERIALS AND METHODS: Mid-coronal dentin of extracted molars was prepared with standardized smear layers and assigned to four groups: control (SU), saliva-contaminated (C + SU), cleaner-treated (K + SU), and saliva-contaminated plus cleaner-treated (C + K + SU). Each group was evaluated either after 24 h storage or after artificial aging by 20,000 thermal cycles (designated "+A"). SBS was measured using a universal testing machine, failure modes were classified, and dentin surfaces were examined by SEM. Data were analyzed with three-way and one-way ANOVA and Bonferroni post hoc tests (α = 0.05). RESULTS: SBS ranged from 9.69 ± 6.03 MPa (C + SU + A) to 16.98 ± 6.53 MPa (SU + A). Saliva contamination significantly reduced SBS after aging (p = 0.002). The cleaner had no significant effect on immediate or long-term bond strength, and aging alone was not statistically significant. Failures were predominantly adhesive at dentin (63.3%). SEM analysis revealed partial collagen exposure with cleaner or adhesive use, but smear plugs remained intact. CONCLUSIONS: Saliva contamination compromised the long-term performance of the universal adhesive. The 10-MDP-containing cleaner did not restore bond strength but also did not adversely affect bonding to dentin. CLINICAL SIGNIFICANCE: Saliva contamination is a critical factor that compromises the durability of adhesive restorations and should be strictly avoided. When contamination occurs, decontamination agents that do not adversely affect tooth structure or interfere with adhesion may be useful. The 10-MDP-containing cleaner tested in this study was safe for dentin and showed a trend toward mitigating the effects of saliva contamination, although it did not fully restore bond strength.