Repair of Aged Polymer-Based CAD/САМ Ceramics Treated with Different Bonding Protocols

Purpose: To compare the microtensile bond strength (pTBS) of different CAD/САМ polymer-based ceramics to a repair composite resin using various bonding protocols. Materials and Methods: Three different CAD/САМ polymer-based ceramics (LAVA Ultimate [LU], 3M ESPE; VITA Enamic [VE], VITA Zahnfabrik; and CeraSmart [CS], GC) were used. Ceramic slices were obtained and subjected to thermal cycling between 5°C and 55°C for 5,000 cycles with a 30-second dwell time. The samples were randomly separated into the following groups: universal adhesive (UB); hydrofluoric acid (HF); sandblasting (SN); HF + UB; HF + ceramic primer (PR) + adhesive (GB); SN + UB; and SN + PR + GB. The repair composite resin (G-aenial Universal Flo, GC) was applied to the samples and subjected to re-aging between 5°C and 55°C for an additional 5,000 cycles. Parallel sections were removed from the specimens, and multiple beam-shaped micro sticks (1.0 mm × 1.0 mm × 10 mm) were prepared for each group. Subsequently, the µTBS test was performed, and the obtained data were statistically analyzed via one- and two-way analysis of variance and Tukey post hoc tests. Scanning electron microscopy (SEM) analysis was also performed. Results: Significant differences were found among the experimental groups (P < .05). The µTBS values of the UB bond groups were higher than those with the GB bond. The effect of pretreatment on pTBS (η_P² = 0.556) was more significant than ceramic type (η_P² = 0.481), and this result was supported by the SEM images. Conclusion: Pretreatment before application of universal adhesive is still needed to repair hybrid ceramic restorations with composite resins. Int J Prosthodont 2021;34:357–364. doi: 10.11607/ijp.6660