Effect of maturation time and adhesive system on the shear bond strength and failure modes of Biodentine™ bonded with resin composite and glass ionomer cement

Objectives: This study aimed (1) to compare the shear bond strength (SBS) and failure modes of Biodentine™ (BD) specimens bonded with resin composite (RC) or high-viscosity glass ionomer cement (HVGIC) at different maturation times and (2) to compare the SBS of BD bonded with RC using different adhesive systems. Materials and Methods: Part I: A total of 120 BD specimens were bonded with either RC or HVGIC (n = 60 each), then divided into four groups (n = 15 each) based on BD maturation time: 12 min, 24 h, 48 h, and 1 week. Part 2: A total of 45 BD specimens matured for 24 h were bonded with RC using 3 adhesives (n = 15 each): (1) Single Bond Universal (SU) with self-etched technique (SU-SE), (2) Adper Single Bond 2 adhesive with etch and rinse technique (AS-ER), and (3) SU adhesive with etch-and-rinse technique (SU-ER). All specimens underwent pH cycling and thermocycling. SBS was measured using a universal testing machine, and failure modes were examined under a stereomicroscope. Results: BD bonded with RC showed significantly higher SBS than BD bonded with HVGIC at all BD maturation times (p < 0.05). No significant SBS differences were found within RC groups, except between the 24-h and 1-week. Cohesive failure predominated in RC specimens (70%), whereas adhesive failure prevailed in HVGIC specimens (71.7%). SU-ER had significantly higher SBS than SU-SE or AS-ER (p < 0.05). Conclusion: BD bonded with RC demonstrated higher SBS than BD bonded with HVGIC. The failure mode in the RC group was predominantly cohesive, whereas in the HVGIC group, it was primarily adhesive. These findings support the clinical applicability of immediate definitive RC placement over BD using a methacryloyloxydecyl dihydrogen phosphate-containing adhesive with an etch-and-rinse strategy.