RESUMO
The effects of tooth brushing could affect the long-term esthetic outcome of composite restorations. This study evaluated the effect of two different emission spectrum light-curing units on the surface roughness, roughness profile, topography and microhardness of bulk-fill composites after in vitro toothbrushing. Valo (multiple-peak) and Demi Ultra (single-peak) curing lights were each used for 10s to polymerize three bulk-fill resin composites: Filtek Bulk Fill Posterior Restorative (FBF), Tetric EvoCeram Bulk Fill (TET) and Surefil SDR Flow (SDR). After 30,000 reciprocal strokes in a toothbrushing machine, the roughness profile, surface roughness, surface morphology, and microhardness were examined. Representative SEM images were also obtained. When light-cured with the Demi Ultra, SDR showed the most loss in volume compared to the other composites and higher volume loss compared to when was light-cured with Valo. The highest surface roughness and roughness profile values were found in SDR after toothbrushing, for both light-curing units tested. FBF always had the greatest microhardness values. Light-curing TET with Valo resulted in higher microhardness compared to when using the Demi Ultra. Confocal and SEM images show that toothbrushing resulted in smoother surfaces for FBF and TET. All composites exhibited surface volume loss after toothbrushing. The loss in volume of SDR depended on the light-curing unit used. Toothbrushing can alter the surface roughness and superficial aspect of some bulk-fill composites. The choice of light-curing unit did not affect the roughness profile, but, depending on the composite, it affected the microhardness.
Assuntos
Resinas Compostas/efeitos da radiação , Lâmpadas de Polimerização Dentária , Escovação Dentária/efeitos adversos , Análise de Variância , Resinas Compostas/química , Dureza/efeitos dos fármacos , Dureza/efeitos da radiação , Cura Luminosa de Adesivos Dentários/métodos , Teste de Materiais , Microscopia Confocal , Microscopia Eletrônica de Varredura , Polimerização , Reprodutibilidade dos Testes , Propriedades de Superfície/efeitos dos fármacos , Propriedades de Superfície/efeitos da radiação , Fatores de TempoRESUMO
El objetivo del presente estudio fue demostrar que los efectos del blanqueamiento dental con Ozono sobre el esmalte son de menor duración en comparación con el Peróxido de Carbamida. Veintidós dientes bovinos fueron divididos en tres grupos: Control y dos grupos experimentales (Peróxido de Carbamida- PC y Ozono - Oz). Los dientes del grupo control no fueron blanqueados y se almacenaron en saliva artificial 24 horas antes. Los dientes de los grupos experimentales fueron expuestos a una aplicación diaria del agente blanqueador por una semana. Después de cada aplicación los dientes se almacenaron en saliva artificial, la que se removió cada tres días. En la superficie vestibular se levantó un bloque de resina a los 0, 1, 7, 14, y 21 días después del blanqueamiento, 24 horas después se midió la fuerza de adhesión. Los datos se analizaron con el test de ANOVA y el post test de Tukey (α=0.05) Los resultados mostraron que existe una diferencia estadísticamente significativa en 0 y 1 días después de realizado el blanqueamiento en ambos grupos, luego de una semana la fuerza de adhesión del grupo Oz fue similar a la del control; mientras que los valores del grupo PC fueron bajos incluso después de tres semanas.
The objective of this study was to demonstrate that effects of ozone bleaching on enamel bond strength have a shorter duration in comparison with carbamide peroxide. Twenty two bovine teeth were divided in three groups: Control and two experimental groups (Carbamide Peroxide-CP and Ozone-OZ). Teeth of control group were not submitted to bleaching and were stored in artificial saliva solution at 37° C for 24 hours. Teeth of experimental groups were exposed to one daily application of the bleaching agent for one week. After each treatment teeth were stored in artificial saliva solution, which was changed every three days. A resin composite block was built-up with Stae and Glacier 0, 1, 7, 14, 21 days post bleaching and microtensile bond strength (µTBS) was carried out 24 hours after adhesive-composite application. Data were analyzed by ANOVA and Tukey post hoc test (α=0.05). Results showed that bond strength were significantly different 0 and 1 day after both bleaching treatments. After one week post-ozone bleaching, bond strength returned to that of the untreated control group. Values for CP group were not suitable even three weeks post-bleaching.