The effects of mouth rinses on the color stability of resin-based restorative materials.

OBJECTIVE: The aim of this study was to assess the color stability of three direct resin-based restorative materials: IPS Empress Direct (Ivoclar Vivadent, Schaan, Liechtenstein), Nano-filled composite (Filtek Z 350 XT, 3 M ESPE, St. Paul, MN, USA), and Nano-hybrid composite (Tetric Evo Ceram, Ivoclar Vivadent, Schaan, Liechtenstein) upon immersion into the following three mouth rinses: Antiseptol (Kahira Pharmaceuticals and Chemical Industries Co. Cairo-Egypt), Flucal (Alexandria Co. Pharmaceuticals Alexandria, Egypt), and Listerine (Johnson & Johnson, UK). MATERIALS AND METHODS: Ninety disc-shaped, 12 mm × 1 mm specimens were divided into three groups according to the type of direct resin-based restorative material used. The specimens were randomly subdivided into three different subgroups (N = 10) in terms of immersion medium. Color change was evaluated prior to and after immersion into the mouth rinses for 24 hours by spectrophotometry (Shimadzu, UV-3101 PC Shimadzu Corporation. Kyoto, Japan). RESULTS: Data were statistically analyzed using two-way analysis of variance (ANOVA) to assess the color stability of the restorative materials. The post hoc Scheffe's test was applied to clarify pair-wise statistical significance. Results with p-values < 0.05 were considered statistically significant. IPS Empress Direct (ΔE = 1.48) exhibited more favorable stability than the other tested composite resins, Filtek Z 350 X (ΔE = 3.05) and Tetric Evo Ceram (ΔE = 10.35). The immersion media elicited a significant effect on the color stability of the tested, resin-based restorative materials, where Flucal elicited the most significant color change, followed by Listerine and Antiseptol, which elicited the least significant color change. CONCLUSIONS: Within the limitation of this laboratory study, the following conclusions could be drawn: (1) The composite structure, namely the resin formulation, which includes the filler size and type of photo-initiator, has a direct impact on its susceptibility to stain by external agents; (2) Mouth rinses can be considered stainable solutions; (3) The chemical formulation of individual mouth rinses can significantly control their ability to stain. CLINICAL SIGNIFICANCE: Patient use of mouth rinses should be subject to dental supervision to control their adverse effects on the aesthetic quality of the restoration. Knowing the composition of the restorative material is important, as is its polymerization cycle and the promotion of adequate surface texture in order to select the appropriate material for each clinical application, and to use it in an effective way to promote its best properties.

Effect of 16% carbamide peroxide bleaching gel on enamel and dentin surface micromorphology and roughness of uremic patients: an atomic force microscopic study.

OBJECTIVES: To investigate the effect of 16% carbamide peroxide bleaching gel on surface micromorphology and roughness of enamel and root dentin of uremic patients receiving hemodialysis using atomic force microscopy (AFM). METHODS: A total of 20 sound molars were collected from healthy individuals (n=10) and uremic patients (n=10). The roots were separated from their crowns at the cemento-enamel junction. Dental slabs (3 mm x 2 mm x 2 mm) were obtained from the buccal surface for enamel slabs and the cervical third of the root surface for dentin slabs. Dental slabs were then flattened and serially polished up to #2500-grit roughness using silicon carbide abrasive papers. Half of the slabs obtained from healthy individuals and uremic patients were stored in artificial saliva and left without bleaching for control and comparison. The remaining half was subjected to a bleaching treatment using 16% carbamide peroxide gel (Polanight, SDI Limited) 8 h/day for 14 days and stored in artificial saliva until AFM analysis was performed. Statistical analysis of the roughness average (Ra) results was performed using one-way ANOVA and Bonferroni post hoc multiple comparisons test. RESULTS: The micromorphological observation of bleached, healthy enamel showed exaggerated prism irregularities more than non-bleached specimens, and this observation was less pronounced in bleached uremic enamel specimens with the lowest Ra. Bleached healthy dentin specimens showed protruded peritubular dentin and eroded intertubular dentin with the highest Ra compared to bleached uremic dentin. CONCLUSIONS: The negative effects of the bleaching gel on uremic tooth substrates are less dramatic and non-destructive compared to healthy substrates because uremia confers different micromorphological surface changes.