Influence of Universal Adhesives With or Without Silane Compared to One‐Step and Two‐Step Silane Agents on Bond Strength to Lithium Disilicate

Objective To evaluate the microshear bond strength (μSBS) to lithium disilicate achieved with universal adhesives (with and without silane) compared with one‐step and two‐step silanes, immediately (IM) and after thermocycling (TC). Chemical interaction (CI) was also assessed. Material and Methods Lithium disilicate blocks were randomly assigned to nine groups ( n = 10) according to surface treatment (silane‐free [ALB; AllBond Universal] and silane‐containing [AMU; Ambar Universal APS Plus, SBU; Scotchbond Universal Plus] universal adhesives, one‐step [PPR; Porcelain Primer, PRO; Prosil, CPR; Ceramic Primer], or two‐step silanes [BIS; Bis‐Silane, EXP; experimental silane, SIL; Silano Mais]). After hydrofluoric acid etching, treatments were applied and resin cement cylinders bonded. μSBS was measured after 24 h or 10,000 thermocycles. CI was analyzed by micro‐Raman spectroscopy. Data were evaluated using two‐way ANOVA and Bonferroni tests ( α = 0.05). Results Surface treatment, evaluation time, and their interaction significantly influenced μSBS ( p < 0.001). IM, two‐step silanes, PPR, and AMU showed higher μSBS, whereas the silane‐free universal adhesive demonstrated lower values. After TC, SIL, BIS, PPR, and AMU maintained higher μSBS. Raman analysis demonstrated comparable CI for AMU and SBU compared with one‐ and two‐step silanes. Conclusions Bond strength was influenced by pretreatment strategy and aging. Two‐step silanes were more consistent, although selected simplified systems achieved comparable performance. Clinical Significance Two‐step silanes remain the most predictable option; however, certain silane‐containing universal adhesives and specific one‐step silanes may offer simplified alternatives when durability limitations are considered.