Adhesive Systems as an Alternative Material for Color Masking of White Spot Lesions: Do They Work?

PURPOSE: To evaluate the color masking effect of infiltration treatment of artificial white spot lesions (AWSL) using a dedicated resin in comparison to different adhesive systems. MATERIALS AND METHODS: Enamel/dentin specimens were obtained from bovine incisors and baseline color was assessed using a reflectance spectrophotometer, according to the CIE L*a*b* system. AWSL were produced using a buffered acid solution and a new color evaluation was performed. The specimens were divided into 8 groups: control: artificial saliva changed daily for 7 days; IC: infiltrating resin Icon; EC: EquiaCoat; FU: Futurabond U; SBU: Single Bond U; SBMP: Scotchbond MP; OB: OptibondFL; BF: Bioforty. After the treatments, the color was evaluated again and the values for the parameters ΔL (change in lightness), Δa (change in chroma), Δb (change in hue), and ΔE (general color difference) were calculated in relation to baseline. Data were analyzed by one-way ANOVA and Tukey's tests. RESULTS: After treatment, ANOVA showed significant differences for all parameters (p = 0.001). Tukey's test showed the greatest lightness reduction (ΔL) for the IC group, followed by EC, FU, and SBU. The SBMP, OB, and BF groups were similar to the control. For Δb values, all groups showed differences in relation to the control, with no differences between them. In relation to ΔE, all groups showed differences in relation to the control (ΔE = 5.24), with no significant differences between them. ΔE values after application of all resinous materials were lower than the threshold of 3.7, indicating effective color masking. CONCLUSIONS: The Icon infiltrant produced a greater lightness reduction of white lesions (ΔL). For general color difference (ΔE), all the resinous materials tested were able to color mask artificial AWSL.

Comparison of different dentin pretreatment protocols on the bond strength of glass fiber post using self-etching adhesive.

INTRODUCTION: This study compared the influence of different irrigants with and without ultrasound or laser irradiation on the bond strength of glass fiber posts using a self-etching adhesive in a supplementary dentin pretreatment. METHODS: Ninety bovine incisor roots were divided into 3 groups according to the irrigant tested: 2% chlorhexidine (CHX) (n = 30); 2.5% sodium hypochlorite (NaOCl) (n = 30), and saline solution (control) (n = 30). Each group was randomly divided into 3 subgroups according to the supplementary dentin pretreatment: ultrasound, Nd:YAG laser, and nonsupplemented (control). A self-etching adhesive system (Futurabond DC; VOCO GmbH, Cuxhaven, Germany) was used, and the glass fiber posts were cemented with dual-cure epoxy-based luting agent (Bifix QM, VOCO GmbH). All roots were sectioned transversely, and the push-out test was performed. Failure mode analysis was also evaluated. RESULTS: Bond strength decreased significantly after the use of 2.5% NaOCl in all root thirds (P < .05). CHX showed no difference in the mean bond strength value compared with saline solution (P > .05). The supplementary dentin pretreatment using the Nd:YAG laser or ultrasound did not improve the bond strength values for both NaOCl and CHX (P > .05). Moreover, the apical third exhibited the lowest mean bond strength values (P < .05). Analysis indicated that the predominant failure mode was the mixed type. CONCLUSIONS: Regardless of the irrigant used, the supplementary dentin pretreatment with ultrasound or laser irradiation showed no improvement in bond strength. Also, the use of NaOCl decreased the bond strength of glass fiber posts using a self-etching adhesive system, whereas CHX preserved it.