The role of bleaching agents (e.g., hydrogen peroxide) in tooth bleaching is quite well-described in a few literature studies and considered as the option choice for those desiring brighter teeth, but alternative methods have emerged to fulfill the desire of patients in a faster, easier, and cheaper way. In this context, whitening over-the-counter (OTC) products are available in several vehicles, such as toothpaste, rinses, gums, paint-on varnishes, and strips, but their effectiveness in terms of bleaching is questioned. This review aimed to describe their mode of action, whitening effectiveness, and harmful effects associated with the indiscriminate use of these products. Dentifrices usually present a combination of abrasives that can induce damage to the tooth surface without evidence of promoting real bleaching. The same was found for rinses, which might present a low pH, with an erosive potential. Charcoal has been included in the composition of these products to improve their whitening effect but there is no evidence supporting it. Regarding strips, they present hydrogen peroxide in a variety of concentrations and are the only OTC products able to promote bleaching. Despite the vehicle, an indication for the use of these products should be made after a careful individual diagnosis of the etiology of the dental staining, considering that most of them seem to be effective only in removing extrinsic stains or preventing their formation over enamel. Also, their indiscriminate use might induce damage and deleterious effects over tooth tissues or gingival tissues. The dentist should be aware of the composition and mode of action of each individual product as they change according to the composition and the vehicle used to recommend the best mode of usage. Still, there is no sound evidence that any of the described OTC products promote a better bleaching effect than the products indicated for a professional.
This study compared the bond strength of a composite repair made with a bulk fill composite and a conventional one using different surface treatments. Specimens were prepared as truncated cones (bases: 4 mm × 2 mm, height: 4 mm) using a bulk fill (OBFa: Filtek One) or a conventional resin (FTKa: Filtek Z250) (n = 66). They were artificially aged (10,000 cycles, 5°C–55°C, 30 sec) and subdivided according to surface treatments: NT—no treatment (control), Abr—abrasion with a diamond tip, and sand—sandblasting with aluminum oxide (50 μm). Treatments were performed over the smaller diameter surface, followed by adhesive (Scothbond Universal) application. A new specimen with similar dimensions was constructed over it using either the OBF or the FTK, totaling 12 groups (n = 11). Bond strength was assessed by tensile test. The data were submitted to two-way ANOVA separately for OBFa and FTKa, followed by Tukey’s test ( p < 0.05 ). For the aged OBFa groups, there was significant differences for composite type and surface treatment, with higher values of bond strength when repaired with the same material (OBFa/OBF > OBFa/FTK), and sandblasting and bur abrasion presented higher values compared to the control group (NT). For the aged FTKa groups, there were no differences for the composite or surface treatment. Therefore, the bulk fill resin composite tested present better repair performance when the same composite was used, while the conventional resin composite was less influenced by the material and the surface treatment performed.
Objective: To evaluate the color stability and degree of conversion of light-cured resin cement with different activator-initiator systems using LED lights with different wavelengths (polywave x monowave). Materials and Methods: Sixteen resin cement samples were made using a circular silicone matrix (7 mm diameter, 0.5 mm thickness) for each of the following tested materials: Variolink Esthetic LC (Ivoclar, color Light+); RelyX Veneer (3M ESPE, color A1); Filtek Z350XT flow resin (3M ESPE, color A1); Allcem Veneer APS (FGM, color A1); NX3 Light cure (Kerr, color A1). Half of the samples were photocured with a monowave LED light (Elipar Deep Cure), and the other half with a polywave LED light (Valo Grand). The initial color of each cement was measured using a high translucency ceramic sample simulating ceramic venner. Color measurements were performed with a reflectance colorimetric spectrophotometer and the data was collected according to the CIE L* a* b* system in two steps. The degree of conversion was measured using an infrared spectrometer by Fourier transform (FTIR / ATR) using the absorbance method. Statistical analysis was performed using ANOVA repeated measures and Tukey’s post hoc tests (p <0.05). Results: For the color analysis, there were no significant differences between the cement related to time versus light curing (p = 0.084) and also related to time versus cement versus light curing (p = 0.142). Among the factors, there was only a statistically significant difference for the type of cement (p <0.01). In contrast, for the photocuring device (p = 0.504) and the interaction between them (p = 0.738), there was no significant difference. For the degree of conversion analysis (DC), it showed a statistically significant difference for both factors, resin cements (p <0.01) and light curing units (p <0.01). Conclusion: The color stability of RelyX cement is low compared to other cements, while Variolink cement presented the best degree of the conversion value.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.