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

OBJECTIVE: To specify the effects of self-etching ceramic primer, Monobond Etch and Prime (MEP), and universal adhesive (UA) on repair bond strength between CAD/CAM blocks and resin composite. MATERIALS AND METHODS: Vita Mark II (VM), IPS e.max CAD (EMAX), Shofu Block HC (SHC), and Tetric CAD (TET) blocks were sliced and thermocycled. They were divided into four groups according to surface treatments (n = 24): control, sandblasting (AL), hydrofluoric acid etching (HF), and MEP application. SEM analysis assessed surface topography. Subdivided, specimens followed distinct adhesive protocols (n = 12): control (silane + adhesive [SA] or adhesive [A] only for MEP group) and UA. Microshear bond strength (µSBS) was measured following resin composite repair. Data were analyzed using two-way ANOVA and Tukey tests (p < 0.05). RESULTS: The µSBS of CAD/CAM blocks was significantly influenced by surface treatment type and adhesive protocol. The highest µSBS values for each block, considering surface treatment + adhesive protocol, were VM, HF + SA, or HF + UA; EMAX, MEP + A; and SHC and TET, AL + SA, or AL + UA. CONCLUSIONS: Except for EMAX, it was not the adhesive protocol that made the significant difference in bond strength for each CAD/CAM block, but the surface treatment. MEP + UA application on glass ceramics lowered µSBS values significantly, so it is not recommended in clinical conditions. CLINICAL SIGNIFICANCE: Repair is an essential therapeutic option, particularly in esthetic restorations, to swiftly repair the impaired esthetics caused by fracture. Repair protocol is dependent on the restorative material, and to have a reliable repair bond strength, the following surface treatment and adhesive protocol combinations are recommended for each CAD/CAM block: VM, HF + SA, or HF + UA; EMAX, MEP + A; and SHC and TET, AL + SA, or AL + UA.

Adhesive Performance of Resin Cement to Glass-Ceramic and Polymer-Based Ceramic CAD/CAM Materials after Applying Self-Etching Ceramic Primer or Different Surface Treatments.

Ensuring optimum bond strength during cementation is vital for restoration success, with the practicality of the process being crucial in clinical practice. This study analyzed the effect of a single-step self-etching ceramic primer (MEP) and various surface treatments on the microshear bond strength (µSBS) between resin cement and glass-ceramic or polymer-based ceramic CAD/CAM materials. Specimens were fabricated from leucite-based glass-ceramic (LEU), lithium disilicate glass-ceramic (LDC), resin nanoceramic (RNC), and polymer infiltrated ceramic network (PICN) (n = 160). They were then classified based on the surface treatments (n = 10): control (no treatment); sandblasting with Al2O3 (AL); etching with hydrofluoric acid (HF); and MEP application. Scanning electron microscopy was used to evaluate the surface topography. µSBS was measured after cementation and thermocycling procedures. Failure modes were examined with a stereomicroscope. Statistical analysis involved two-way analysis of variance and Tukey HSD tests with a significance level of 0.05. µSBS was significantly influenced by both surface treatment and CAD/CAM material type. The most enhanced µSBS values for each material, regarding the surface treatment, were: LEU and LDC, HF; RNC, AL; PICN, AL or HF. MEP significantly increased the µSBS values of CAD/CAM materials except RNC, yet it did not yield the highest µSBS values for any of them.

Effect of surface treatments and universal adhesive application on the microshear bond strength of CAD/CAM materials.

PURPOSE: The aim of this study was to evaluate the microshear bond strength (µSBS) of four computer-aided design/computer-aided manufacturing (CAD/CAM) blocks repaired with composite resin using three different surface treatment protocols. MATERIALS AND METHODS: Four different CAD/CAM blocks were used in this study: (1) flexible hybrid ceramic (FHC), (2) resin nanoceramic (RNC), (c) polymer infiltrated ceramic network (PICN) and (4) feldspar ceramic (FC). All groups were further divided into four subgroups according to surface treatment: control, hydrofluoric acid etching (HF), air-borne particle abrasion with aluminum oxide (AlO), and tribochemical silica coating (TSC). After surface treatments, silane was applied to half of the specimens. Then, a silane-containing universal adhesive was applied, and specimens were repaired with a composite, Next, µSBS test was performed. Additional specimens were examined with a contact profilometer and scanning electron microscopy. The data were analyzed with ANOVA and Tukey tests. RESULTS: The findings revealed that silane application yielded higher µSBS values (P<.05). All surface treatments were showed a significant increase in µSBS values compared to the control (P<.05). For FHC and RNC, the most influential treatments were AlO and TSC (P<.05). CONCLUSION: Surface treatment is mandatory when the silane is not preferred, but the best bond strength values were obtained with the combination of surface treatment and silane application. HF provides improved bond strength when the ceramic content of material increases, whereas AlO and TSC gives improved bond strength when the composite content of material increases.