Effect of Bleaching Protocols on the Microhardness and Surface Roughness of Composite Resins with Different Filler Architectures: An In Vitro Study
Tallennettuna:
| Tekijät: | , , |
|---|---|
| Aineistotyyppi: | artículo original |
| Tila: | Versión publicada |
| Julkaisupäivä: | 2026 |
| Kuvaus: | The rising clinical demand for tooth bleaching necessitates a comprehensive understanding of its impact on pre-existing restorations. This study aimed to evaluate the effect of two bleaching protocols on the microhardness and surface roughness of four composite resins with distinct filler architectures. Thirty-six discs were manufactured for each composite resin: microhybrid (Opallis), submicron (Brilliant EverGlow), nanofilled (Filtek™ Z350 XT), and nanohybrid (Tetric® N-Ceram). Specimens were randomly assigned (n=12) to two bleaching protocol-35% hydrogen peroxide (HP) and 10% carbamide peroxide (CP)-and a control group (distilled water). A total of 144 discs were evaluated for microhardness and 144 for surface roughness. Data were analyzed using Wilcoxon, Kruskal-Wallis, and Mann-Whitney U tests with Bonferroni correction, as well as the Scheirer-Ray-Hare test (α=0.05). Bleaching protocols significantly altered surface properties (p<0.001), indicating that the bleaching effect is highly dependent on the specific material structure. A significant interaction was observed between the bleaching agent and filler architecture (p<0.01). The microhybrid resin (Opallis) exhibited the highest reduction in microhardness (∆ VHN: 36.2) and the greatest increase in roughness (∆ Ra: 0.40 µm) under 35% HP, exceeding the clinically acceptable threshold of 0.2 µm for biofilm accumulation. Conversely, the nanofilled architecture (Filtek™ Z350 XT) maintained structural and topographical stability, showing no significant differences compared to the control group (p>0.05), regardless of the protocol. Nanohybrid and submicron resins demonstrated intermediate levels of degradation. The surface stability of resin composites is determined by a synergistic interaction between the bleaching protocol and filler architecture, with microhybrid structures being the most susceptible. Bleaching with 35% HP was more deleterious than 10% CP. The nanofilled architecture provides superior resilience to oxidative stress. |
| Maa: | Portal de Revistas UCR |
| Organisaatio: | Universidad de Costa Rica |
| Repositorio: | Portal de Revistas UCR |
| Kieli: | Inglés |
| OAI Identifier: | oai:portal.revistas.ucr.ac.cr:article/5796 |
| Linkit: | https://revistas.ucr.ac.cr/index.php/rOdontos/article/view/5796 |
| Sanahaku: | Tooth bleaching; Hydrogen peroxide; Carbamide peroxide; Resin composites; Surface properties; Hardness tests; Microhardness; Filler architecture. Blanqueamiento dental; Peróxido de hidrógeno; Peróxido de carbamida; Resina compuesta; Propiedades superficiales; Pruebas de dureza; Microdureza; Arquitectura de relleno. |