Effect of surface treatment with laser on repair bond strength of composite resin to ceramic

Abstract

Background: Small chipping or fracture of ceramic restorations may be repaired by composite
resin instead of replacing the restoration. This method is faster and cheaper compared to restoration
replacement. Several strategies have been suggested to obtain a high repair shear bond strength (SBS).
This study aimed to assess the efficacy of some new ceramic surface treatments (laser and universal
adhesive) to enhance the repair bond strength of composite resin to ceramic compared to the
conventional method.
Materials and Methods: This in vitro study evaluated 80 IPS Empress Esthetic ceramic plates
in eight groups (n = 10). The ceramic surface was polished with 320‑grit silicon carbide paper
under running water, rinsed with water spray for 10 s and dried. The samples were then divided
into two subgroups for mechanical surface preparation with hydrofluoric (HF) acid and Er: YAG
laser (2 W, 200 m J, 10 Hz, 10 s). Each group was divided into two subgroups for use/no use of
silane. The conventional or universal adhesive was then applied on the samples in each subgroup.
Composite cylinders were bonded to the ceramic surface using plastic tubes. The samples were
stored in distilled water at 37°C for 24 h and subjected to an SBS test. Data were analyzed using
one‑way ANOVA (P < 0.05).
Results: The interaction effect of variables on SBS was significant. Maximum SBS was noted in HF
acid + silane + conventional adhesive group (mean: 12.0481 MPa). Minimum SBS was noted in the
laser + conventional adhesive group (mean: 2.5766 MPa). Surface treatment with HF acid yielded
significantly higher SBS than laser (P < 0.001). The interaction effect of conventional/universal
adhesive and use/no use of silane on SBS was statistically significant.
Conclusion: The repair SBS was higher in groups treated with HF acid compared to laser. Ceramic
surface treatment with HF plus silane plus conventional adhesive yielded a higher SBS as well as
HF plus Universal adhesive. Thus, the application of silane as a separate step can be omitted in the
repair of ceramic restorations with universal adhesives.
Key Words: Bond strength, ceramic, laser, resin composite