Efecto de diferentes condiciones y modos de aplicación sobre la fuerza de unión de los adhesivos a la dentinaEffect of different conditions and modes of application on bond strength of adhesives to dentine / Effect of different conditions and modes of application on bond strength of adhesives to dentine

Objective: To evaluate the microtensile bond strength in different dentine conditions (etched-E, non-etched-N, dry-D and wet-W) of a multimode adhesive (Scotchbond Universal-SU, 3M/ESPE) and a total etching adhesive (Ambar-AB, FGM) using a sonic device (Smart Sonic Device-SD, FGM). Material and methods: In this in vitro study, ninety six sound extracted human molars were divided into 12 groups (n=8) according to different dentine conditions and adhesive systems. Enamel was removed and the middle dentine surfaces were polished. Each adhesive system was applied according to the different dentine conditions, and composite resin blocks were incrementally built up and stored for 24 hours. Specimens were sectioned into sticks and bond strength data were analyzed with the Kruskal-Wallis test and Mann-Whitney U tests. Results: No effects of sonic application and were observed. In general, AB showed lower results compared to the SU. E and N conditions did not statistically affect the bond strength of SU groups. Dry dentine presented statistically superior bond strength values when compared to wet dentine for SU/E/SD group. Conclusion: Adhesion of dry dentine with multimode adhesive system may be superior to wet dentine with sonic application. The modes of application had no influence in bond strength of studied adhesives.

Objetivo: Evaluar la resistencia de la unión microtensil en diferentes condiciones de dentina (grabado-E, sin grabado-N, seco-D y húmedo-W) de un adhesivo multimodo (Scotchbond Universal-SU, 3M/ESPE) y un adhesivo de grabado total (Ambar-AB, FGM) utilizando un dispositivo sónico (Smart Sonic Device-SD, FGM). Material y Métodos: En este estudio in vitro, noventa y seis molares humanos extraídos sanos se dividieron en 12 grupos (n=8) de acuerdo con diferentes condiciones de dentina y sistemas adhesivos. Se eliminó el esmalte y se pulieron las superficies centrales de la dentina. Cada sistema adhesivo se aplicó de acuerdo con las diferentes condiciones de dentina, y los bloques de resina compuesta se acumularon de forma incremental y se almacenaron durante 24h. Las muestras se seccionaron en barras y los datos de resistencia de la unión se analizaron con la prueba de Kruskal-Wallis y la prueba de U de Mann-Whitney. Resultado: No se observaron efectos de la aplicación sónica. En general, AB mostró resultados más bajos en comparación con el SU. Las condiciones E y N no afectaron estadísticamente la fuerza de unión de los grupos SU. La dentina seca presentó valores de fuerza de adhesión estadísticamente superiores en comparación con la dentina húmeda para el grupo SU/E/SD. Conclusión: La adhesión de la dentina seca con un sistema adhesivo multimodo puede ser superior a la dentina húmeda con aplicación sónica. Los modos de aplicación no tuvieron influencia en la resistencia de la unión de los adhesivos estudiados.

Influence of different light-curing units in surface roughness and gloss of resin composites for bleached teeth after challenges.

The aim of this study evaluates the surface roughness and gloss of resin composites for bleached teeth, using different modes of light curing and photoinitiators after challenges. Eighty discs were made with Filtek Z350XT (camphorquinone) and Vit-l-escence (camphorquinone, amine and lucerin-TPO). Forty disks were light cured by a monowave LED and forty with a polywave LED. Roughness and gloss analysis were made. The specimens were exposed to brushing and hydrochloric acid (HCl) and analyzed again. The data were analyzed by two-way ANOVA analysis of variance for repeated measures, considering each challenge separately. Afterwards, Tukey test was applied for multiple comparisons (p ≤ 0.05). All resins had a significant increase in roughness after brushing with polywave device and only Vit-l-escence presented significant increased after HCl. Regarding the surface gloss, no influence on light-curing units was found for all resins after toothbrushing and after HCl for Vit-l-escence. All resins showed significant decrease in gloss after the challenges. The type of LED device did not influence the roughness and surface gloss of resin composites for bleached teeth after the challenges.

Fracture resistance of Class II glass-ionomer cement restorations.

PURPOSE: To investigate in vitro the effect of retentive grooves, GIC type and insertion method on the fracture resistance of Class II glass-ionomer cement (GIC) restorations. METHODS: Premolars were divided into 12 groups (n = 10) according to three variables: retentive grooves [presence (PR) or absence AR)], GICs type [Ketac-Molar (KM), Fuji VIII (F8) and RelyX Luting (RX)], and insertion method [syringe injector (SI) or spoon excavator (SE)]. The specimens were subjected to fracture resistance test. Data were submitted to three-way ANOVA and multiple comparisons were performed using a Tukey test (P < 0.05). RESULTS: Mean fracture resistance values (Kgf) +/- standard deviations (SD) were: KM (PR+SI) = 65.66 +/- 2.5; KM (PR+SE) = 62.58 +/- 2.1; KM (AR+SI) = 57.11 +/- 1.9; KM (AR+SE) = 51.94 +/- 2.3; F8 (PR+SI) = 63.05 +/- 2.1; F8 (PR+SE) = 60.12 +/- 2.3; F8 (AR+SI) = 55.11 +/- 1.9; F8(AR+SE) = 49.20 +/- 1.6; RX (PR+SI) = 50.99 +/- 2.4; RX (PR+SE) = 48.81 +/- 2.5; RX (AR+SI) = 45.53 +/- 2.6; RX (AR+SE) = 41.88 +/- 3.0. Statistically significant differences were observed among all the groups tested (P = 0.001). There was significant difference when pooled means for GIC type were compared with retentive grooves (P = 0.01) and when pooled means for retentive grooves were compared with insertion method (P = 0.01).