Repair Bond Strength of Composite Resin to Aged Resin and Glass-Matrix CAD/CAM Ceramic Materials Using Two Different Repair Systems

Abstract

This study evaluates the repair bond strength of resin-matrix and glass-matrix CAD/CAM ceramic materials based on two repair systems. Thirty specimens measuring 2.5 mm in thickness were prepared from Crystal Ultra (CU), Vita Enamic (EN), Lava Ultimate (LU), Cerasmart (CS), and Vitablocs Mark II (VM2) materials and aged for 5000 thermal cycles. Specimens were randomly allocated into three groups: control, Monobond-S (MS) primer, and Monobond Etch & Prime (MEP). Composite resin (Tetric N Ceram) (5 mm in diameter and 2 mm thick) was packed and light-cured onto treated specimen surfaces. Subsequently, the specimens’ shear bond strength (SBS) was evaluated, and failure modes was recorded. Statistical analysis was performed using factorial ANOVA and Tukey’s post hoc tests (a = 0.05). The factorial ANOVA revealed significant interactions between the material type and repair system, which was significant (p < 0.01). The highest and lowest SBS were obtained for CU (27.09 ± 1.11) and VM2 (4.30 ± 0.59) in MS and control groups, respectively. In all the groups, CU demonstrated higher SBS, whereas VM2 demonstrated lower SBS. There were no significant differences in SBS between EN and LU, and CS and CU in all the study groups (p > 0.05). The Monobond-S repair system provided non-significantly higher SBS compared to the MEP systems, except for VM2 and LU materials. The new resin-matrix CAD/CAM material demonstrated the highest SBS compared to the other materials for both conventional and MEP repair systems. Both repair systems showed clinically acceptable bond strength and allowed for successful repair of the resin-matrix ceramic materials.

Influence of surface treatments and adhesive protocols on repair bond strength of glass‐matrix and resin‐matrix CAD/CAM ceramics

“…As one of the surface treatments, AL is especially recommended for resin‐matrix ceramics as it removes the smear layer after milling, creates a clean surface for micromechanical retention, 22 and increases the surface area by roughening 13,14,19,33,39 . Roughening also increases the surface energy and wettability of the restorative materials, hence micromechanical interlocking and bond strength increases 23,33 .…”

“…The reliable and durable bonding of different materials to each other has long been a goal in the field of dentistry. To ensure adequate bond strength between inert restorative materials and resin composites, it is recommended to employ mechanical or chemical surface treatments 13–20 . These treatments aim to enhance the bonding capability by modifying the surface properties of the restorative materials.…”

“…As a result, Monobond Etch and Prime (MEP; Ivoclar Vivadent AG, Schaan, Liechtenstein) is introduced as a revolutionary self‐etching ceramic primer that can mildly etch with ammonium polyfluoride and silanize simultaneously with trimethoxypropyl methacrylate to increase bond strength 30–32 . Use of MEP is suggested especially for glass ceramics, but due to the disadvantages of sandblasting mentioned above, researchers also conducted studies on MEP's efficiency on resin‐matrix ceramics and found promising results which further should be investigated 14,16 . Researchers also reported that adhesive systems should be applied after surface treatments to enhance the repair bond strength 11,33 .…”

“…There are limited studies analyzing the effect of MEP and UA applications on the repair performance of CAD/CAM blocks, and the results are contradictory 14,30,33,35,36 . Several studies have presented differing perspectives on the performance of MEP compared to HF with silane application on glass ceramics 6,30,36 .…”

“…While certain reports indicate that MEP achieves comparable bond strength to HF with silane, others suggest that HF in conjunction with silane yields greater bond strength than MEP 6,30,36 . Some studies advocate for the preference of MEP for both glass ceramics and resin‐matrix ceramics, whereas others suggest that it enhances bond strength for specific resin‐matrix ceramics but may not yield similar success for other types of resin‐matrix ceramics 4,14 . In addition, considering UA, certain investigations reported that they increase the bond strength of resin‐matrix ceramics and zirconia, whereas some reported that they do not perform a repair bond strength as robust as that achieved with the material‐specific primer for glass–ceramics and alloys 33,35 .…”