Bond Strength of Bulk-Fill Resin Repairs: Impact of Surface and Adhesive Protocols

Samuel Eleutério Paiva Sousa; Fiorella Elizabeth Arévalo Tarrillo; Maria Paula Novaes Camargo Manna; Sandra Ribeiro de Barros da Cunha; Maria Ângela Pita Sobral

doi:10.15517/4tjc3431

Although repair is a conservative approach that preserves healthy tooth structure, there is still no consensus on the most effective surface treatment and adhesive protocol for repairing aged bulk-fill composite resin restorations. The objective of the study was to evaluate the effect of diamond bur roughening and aluminum oxide (Al2O3) sandblasting as surface treatments combined with different adhesive protocols on the repair bond strength (BS) of aged bulk-fill composite resin.150 Filtek™ One resin discs were thermocycled (5,000 cycles of 5°/55°C) and divided into three surface treatment groups (n=50): no treatment (NT), roughening with diamond bur (B), and sandblasting with Al2O3 (Al). Each group was further subdivided according to five adhesive protocols (n=10): no adhesive (NA), Adper Single Bond 2 (SB), Single Bond Universal (SBU), Silane + Adper Single Bond 2 (S+SB), and Silane (S). Three Bulk Fill resin cylinders were fabricated for each specimen to simulate repair, followed by micro-shear bond strength testing and fracture pattern analysis after 24-hour storage in deionized water. Two-way ANOVA and Tukey's test (α=0.05) were applied. When B or Al was applied, only NA showed inferior results. No statistical differences were found between B/SB, B/SBU, B/S+SB, and B/S, as well as between Al/SB, Al/SBU, Al/S+SB, and Al/S. Al/SBU showed higher bond strength than B/SBU. The most frequent fracture patterns for B and Al were cohesive and mixed, while for NT, it was adhesive. Surface treatment with B or Al, combined with an adhesive protocol, improved bond strength. Surface treatment is crucial for bulk-fill composite resin repair, enhancing bond strength with adhesive systems, with or without silane. A universal adhesive containing silane is as effective as adhesive-silane combinations, offering superior bond strength on Al2O3 blast-treated surfaces. Aunque la reparación es un enfoque conservador que preserva la estructura dental sana, no existe consenso sobre el tratamiento de superficie ni el protocolo adhesivo más eficaz para restauraciones de resina compuesta bulk-fill. Este estudio evaluó el efecto del asperizado con fresa diamantada y del arenado con óxido de aluminio (Al2O3, combinados con distintos protocolos adhesivos, sobre la resistencia de unión de reparación (BS) de resina compuesta bulk-fill envejecida. Se fabricaron 150 discos de resina Filtek™ One, sometidos a termociclado (5.000 ciclos de 5°/55 °C) y divididos en tres grupos de superficie (n=50): sin tratamiento (NT), asperizado con fresa diamantada (B) y arenado con Al2O3 (Al). Cada grupo se subdividió según cinco protocolos adhesivos (n=10): sin adhesivo (NA), Adper Single Bond 2 (SB), Single Bond Universal (SBU), Silano+Adper Single Bond 2 (S+SB) y Silano (S). Se fabricaron tres cilindros de resina Bulk Fill por espécimen para simular la reparación. Luego se evaluó BS mediante microcizallamiento y se analizó el patrón de fractura tras 24 horas de almacenamiento en agua. Los datos se analizaron mediante ANOVA de dos vías y prueba de Tukey (α=0,05). Con B o Al, solo NA mostró resultados inferiores. No se observaron diferencias significativas entre B/SB, B/SBU, B/S+SB y B/S, ni entre Al/SB, Al/SBU, Al/S+SB y Al/S. Al/SBU presentó mayor BS que B/SBU. Los patrones de fractura más frecuentes para B y Al fueron cohesivos y mixtos, mientras que para NT predominó el adhesivo. En conclusión, el tratamiento de superficie con B o Al, combinado con un protocolo adhesivo, mejora la BS. El tratamiento de superficie es clave para la reparación de resina compuesta bulk-fill, potenciando la eficacia de los sistemas adhesivos con o sin silano. Un adhesivo universal es tan eficaz como la combinación adhesivo-silano, ofreciendo mayor BS en superficies tratadas con arenado de Al2O3.

Bond Strength of Bulk-Fill Resin Repairs: Impact of Surface and Adhesive Protocols

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