Impact of self-adhesive resin cements on shear bond strength to CAD/CAM silicate ceramics

BACKGROUND: The bond strength between self-adhesive resin cements (SARCs) and computer-aided design/computer-aided manufacturing (CAD/CAM) ceramics is crucial for restoration durability, yet data on the aging effects of different SARCs remains limited. OBJECTIVES: The aim of the study was to evaluate the shear bond strength (SBS) and failure modes of various SARCs on 2 CAD/CAM silicate ceramics after thermal aging. MATERIAL AND METHODS: A total of 360 samples from 2 ceramics (CEREC Tessera™ HT (CTS group); IPS Empress CAD LT (IEC group)) were treated with hydrofluoric acid (HF) and bonded with 6 SARCs: G-CEM ONE™ (GCO); Maxcem Elite™ (MXC); Nexus™ Universal (NXU); SpeedCEM® Plus (SPC); RelyX™ Universal (RLX); and PANAVIA™ SA Cement Universal (PSA). The samples underwent water storage (24 h, 37°C) or thermal aging (30 days, 20,000 cycles, 5-55°C). The shear bond strength and failure modes were measured, with the bonding interfaces being assessed via scanning electron microscopy (SEM). A multifactorial analysis of variance (ANOVA) was applied for the statistical analysis. RESULTS: Significant differences were identified in aging (F = 117.64, p < 0.001), ceramic types (F = 28.91, p < 0.001) and among SARCs (F = 34.79, p < 0.001). The highest SBS post-aging was found with IEC+GCO (24.92 ±2.90 MPa) and CTS+MXC (21.68 ±3.16 MPa), while the lowest SBS was recorded with CTS+PSA (6.22 ±4.31 MPa). Failure modes shifted from cohesive to mixed after thermocycling. CONCLUSIONS: All tested SARCs bond effectively to CAD/CAM ceramics, with GCO and PSA being recommended for IEC ceramics, and MXC for CTS ceramics to optimize bond strength.