ABSTRACT
OBJECTIVES: To evaluate the effects of 10% carbamide peroxide (CP) with two different thickeners, carbopol (CPc) and natrosol (CPn), on color variation (CV), tooth sensitivity (TS), and cytotoxicity (CC). METHODS: Seventy subjects were distributed into the CPc or CPn groups (n = 35), in a parallel group, randomized, controlled, single-blind clinical trial. Bleaching gels were used by volunteers for 4 h daily for 2 weeks. Color evaluation was performed using a reflectance spectrophotometer, before bleaching treatment (BT), immediately after the first and second weeks of BT, and 1 week and 1 month after BT ended. TS was evaluated using two pain scales, before, during, and after BT. CC was evaluated using MTT after exposure of MDPC-23 cells to the bleaching gels for 4 h. Epoxy replicas of the subjects teeth were made before and after BT and analyzed using a scanning electronic microscope. The data was analyzed using statistical methods. RESULTS: CV and TS showed similar variation between both bleaching gels (p ≤ 0.05). None of the protocols affected cellular metabolism or the surface morphology of enamel. CONCLUSIONS: Bleaching gels with carbopol and natrosol as thickening agents produced similarly effective tooth bleaching and TS, but did not cause cytotoxicity. CLINICAL RELEVANCE: Natrosol could be an alternative as a thickener used in bleaching gels due to its similar bleaching effect and TS when compared with Carbopol.
Subject(s)
Acrylic Resins/chemistry , Carbamide Peroxide/chemistry , Dentin Sensitivity , Tooth Bleaching Agents/chemistry , Tooth Bleaching , Animals , Cell Line , Color , Female , Gels , Humans , Male , Mice , Peroxides , Single-Blind Method , Young AdultABSTRACT
OBJECTIVES: Evaluate the effect of different storage conditions on bleached enamel using Knoop microhardness (KHN) and colour variation. METHODS: Forty-eight tooth blocks were divided into four groups (n=12), based on storage media (SM): purified water (PW), artificial saliva (AS), natural saliva (NS), in situ (IS). Three whitening sessions were carried out using 35% hydrogen peroxide, with a week interval. Colour and KHN measurements were taken before the samples were placed in the SM (t1), after 24h in the SM (t2), and after 24h at the end of the bleaching treatment (t3). Two extra samples from each group were analysed using a scanning electron microscope (SEM). KHN results were analysed by PROC-MIXED and Tukey-Kramer test (α=0.05), and colour changes were evaluated using ΔL, Δa, Δb, ΔE between the different times Δ1(t1-t2), Δ2(t2-t3) using the Kruskal-Wallis test and Dunn's test (α=0.05). RESULTS: Significant statistical difference was noted in KHN at t3, with the lowest values found for PW. As for colour analysis in ΔE2 and Δb2, IS showed values that were statistically lower when compared to AS. Likewise, there were differences between PW and AS in relation to IS when evaluating ΔL2. In addition, NS showed similar values to IS. CONCLUSIONS: The storage conditions had different effects on the physical properties of bleached enamel. NS was the only SM that showed similar behaviour to IS. CLINICAL SIGNIFICANCE: NS proved an effective SM in the protection and recovery of damage caused by bleaching and is a viable SM for in vitro studies.
Subject(s)
Dental Enamel/chemistry , Dental Enamel/drug effects , Hydrogen Peroxide/chemistry , Tooth Bleaching Agents/chemistry , Tooth Bleaching , Adult , Animals , Cattle , Color , Dental Enamel/ultrastructure , Female , Hardness , Humans , In Vitro Techniques , Male , Peroxidase/chemistry , Preservation, Biological , Saliva/chemistry , Saliva, Artificial/chemistry , Temperature , Time Factors , Water/chemistry , Young AdultABSTRACT
O objetivo deste artigo foi verificar a qualidade de três câmaras escuras e de três filmes radiográficos disponíveis comercialmente, analisando digitalmente a densidade base e velamento (DBV) e o contraste. Foram utilizados 72 filmes radiográficos periapicais, marcas Agfa®, Dentix® e Kodak®, divididos em quatro grupos submetidos a diferentes dispositivos de processamento. Os filmes foram processados, digitalizados e analisados no software Image Tool®. No filme Agfa®, ocorreu diferença estatisticamente significante na DBV em relação aos grupos. No Dentix®, a DBV e o contraste do grupo controle diferiram de forma significante. No Kodak®, a DBV permaneceu constante em todos os grupos. A DBV do filme Kodak® permaneceu constante em todas as câmaras escuras, ao contrário dos outros filmes. O contraste dos três filmes radiográficos sofreu alteração.
