Bonding States of In Vitro Class 2 Direct Resin Composite Restoration Applied by Various Incremental Techniques

• Published in: Materials Vol. 14; no. 20; p. 6037
• Main Authors: Okada, Misato, Maeno, Masahiko, Nara, Yoichiro
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 13-10-2021; MDPI
• Subjects: Adhesives; Bond strength; Bonding strength; Clinical medicine; Composite materials; Cyclic loads; Dentin; Dentistry; Failure analysis; Light; Mechanical properties; Physical properties; Polymer matrix composites; Resins; Restoration; Weibull modulus; United States > US; Japan
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma14206037

Incremental techniques are always required for clinical cases of deep and/or large cavities restored with resin composite materials. The purpose of this study was to examine the bonding states of class 2 direct resin composite restoration applied by various incremental techniques after cyclic loading to simulate the intra-oral environment to define the appropriate technique. Three types of resin composites, namely, bulk-fill (B), flowable (F), and conventional resin composite (C), were applied to standardized class 2 cavities by incremental techniques with single- or bi-resin restoratives. After cyclic loading, the micro-tensile bond strength (μ-TBS) of the dentin cavity floor was measured. The Weibull modulus and Weibull stress values at 10%/90% probability of failure were analyzed. Single-resin incremental restorations with B or F and bi-resin incremental restorations with F + B and F + C demonstrated superior μ-TBS (quantitative ability), bonding reliability, and durability (qualitative ability) compared with the single-resin restoration with C (as control). Furthermore, F + B and F + C restoration yielded an excellent performance compared with the single-resin restorations with B, F, and C. In particular, the F + C restoration, which indicates not only the maximum mean µ-TBS, but also the highest values of the Weibull parameters, may be the optimal restoration method, including the esthetic benefits.