Influence of Surface Preparation Methods on Fracture Behavior of Nanohybrid and Monochromatic Composite Resins: A Stereomicroscopic Analysis

OpenAlex İngilizce

Objective: This study investigates the effect of different surface preparation methods on the fracture behavior of nanohybrid and monochromatic composite resins. Materials and Methods: Sixty extracted anterior teeth were embedded in acrylic and divided into two groups to be restored with monochromatic composite resin (Omnichroma, Tokuyama, Japan) and nanohybrid composite resin (Essentia, GC, Japan). Each group was subdivided based on roughening method: acid-etched control, thick/medium-grit disc and Er,Cr: YSGG laser. All teeth were restored using universal adhesive system, subjected to 5000 thermal cycles, and stored in distilled water at 37°C for 24h. Shear bond strength were measured using a universal testing machine (Shimadzu Corp., Kyoto, Japan), modes of failure were evaluated using a stereomicroscope (Leica-M27.5, Leica Microsystems, Germany). The data were analyzed using IBM SPSS V23. Yates Correction and Monte Carlo Corrected Fisher's Exact Test were used to examine the relationship between composites, surface preparation techniques and fracture types. The significance level was set at p<0.05. Results: Surface roughening improved the bond strength. Adhesive fractures were predominant in most groups, except in the Er,Cr: YSGG laser-treated samples, where mixed fractures were more common. There was no statistically significant difference between composites, fracture types (p=1) or between surface preparation techniques and fracture types (p=0.235). Conclusion: Surface preparation methods such as acid etching and mechanical roughening resulted in higher adhesive failure rates, while laser etching led to more mixed failures. Laser etching is a minimal invasive technique with promising results but requires further research to optimize its clinical application.