Color changes induced by light curing of resin composites

Color changes that occur after the light-activation of resin composites should be understood. Objective: To evaluated the influence of light-curing devices on the color of resin composites immediately after light-activation and after one-week, at 37ºC, into water storage. Material and methods: Three A2-shade composites (Z100, Z250, and Z350), and four light-curing devices (three halogens and one LED) were evaluated. Seventy-five cylindrical specimens were light-activated for 20s. CIE-Lab color was analyzed using a spectrophotometer. Color changes between uncured and immediately light-activated materials (∆E1), and between immediately light-activated and one-week-37˚C-water-stored materials (∆E2) were obtained. Data were evaluated by two-way Anova, followed by Tukey test (α = 0.05). Results: For ∆E1, composites (p = 0.0008), lights (p = 0.015), and the interaction (p = 0.017) were significant. Z100 showed the smallest value (3.08 ± 1.73). The halogen 210 mW/cm2device showed the smallest ∆E1(3.09 ± 1.25), while the LED 200mW/cm2showed the highest value (4.94 ± 2.37). For ∆E2, composites (p = 0.00016), lights (p < 0.0001), and the interaction effect (p = 0.0002) were significant. Z350 showed the smallest value (2.24 ± 1.17). The halogen 400mW/cm2device showed the smallest ∆E2(2.15 ± 2.15), while the halogen device 525mW/cm2showed the highest value (4.45 ± 2.15). Conclusion: The color of resin composites change significantly from the uncured to the cured and water-aged phases

Avaliação da capacidade de dissolução tecidual de diferentes soluções de hipoclorito de sódio em tecido conjuntivo e muscular de ratos

 Objetivo: analisar a capacidade de dissolução tecidual de diferentes soluções de hipoclorito de sódio em tecido conjuntivo e muscular esquelético de ratos. Metodologia: foram obtidos 60 fragmentos de tecido conjuntivo (dorso) e muscular esquelético (língua) de ratos da linhagem Wistar, que foram submetidos à ação solvente das soluções de hipoclorito de sódio comercializadas, prontas para uso, Hipoclor 1%, HW 1% e 2,5%, Limpa Bem 2,5% e soluções manipuladas nas mesmas concentrações. O tempo de dissolução foi cronometrado. O método de titulometria com iodo foi utilizado para confirmação do teor de cloro ativo das soluções utilizadas. Resultados: a análise estatística revelou diferença não significante entre os dois diferentes tecidos (p0.05) e apresentou diferença significante (pConclusão: ambos tecidos podem ser utilizados para a verificação da capacidade de dissolução tecidual do hipoclorito de sódio e que esta obedece uma relação diretamente proporcional a concentração do teor de cloro ativo.Palavras-chave: Dissolução Tecidual; Hipoclorito de Sódio; Preparo do Canal Radicular

Influence of antimicrobial solutions in the decontamination and adhesion of glass-fiber posts to root canals

AbstractObjective This study evaluated the effect of root canal disinfectants on the elimination of bacteria from the root canals, as well as their effect on glass-fiber posts bond strength.Material and Methods Fifty-three endodontically treated root canals had post spaces of 11 mm in length prepared and contaminated with E. faecalis. For CFU/ml analysis, eight teeth were contaminated for 1 h or 30 days (n=4). Teeth were decontaminated with 5% NaOCl, 2% CHX, or distilled water. As control, no decontamination was conducted. After decontamination, sterile paper points were used to collect samples, and CFU/ml were counted. For push-out, three groups were evaluated (n=15): irrigation with 2.5% NaOCl, 2% CHX, or sterile distilled water. A bonding agent was applied to root canal dentin, and a glass-fiber post was cemented with a dual-cured cement. After 24 h, 1-mm-thick slices of the middle portion of root canals were obtained and submitted to the push-out evaluation. Three specimens of each group were evaluated in scanning electron microscopy (SEM). Data were analyzed with one-way ANOVA and Dunnett’s T3 test (α=0.05).Results The number of CFU/ml increased from 1 h to 30 days of contamination in control and sterile distilled water groups. Decontamination with NaOCl was effective only when teeth were contaminated for 1 h. CHX was effective at both contamination times. NaOCl did not influence the bond strength (p>;0.05). Higher values were observed with CHX (

Adhesion of Endodontic Sealers to Human Root Dentine Submitted to Different Surface Treatments

Objective: To evaluate the adhesion of the endodontic sealers Epiphany, Apexit Plus, and AH Plus to root canal dentin submitted to different surface treatments, by using the push-out test. Methods: One hundred twenty-eight root cylinders obtained from maxillary canines were embedded in acrylic resin, had the canals prepared, and were randomly assigned to four groups (n = 32), according to root dentin treatment: (I) distilled water (control), (II) 17% EDTAC, (III) 1% NaOCl and (IV) Er:YAG laser with 16-Hz, 400-mJ input (240-mJ output) and 0.32-J/cm(2) energy density. Each group was divided into four subgroups (n = 8) filled with Epiphany (either dispensed from the automix syringe supplied by the manufacturer or prepared by hand mixing), Apexit Plus, or AH Plus. Data (MPa) were analyzed by ANOVA and Tukey's test. Results: A statistically significant difference (p < 0.01) was found among the root-canal sealers, except for the Epiphany subgroups, which had statistically similar results to each other (p > 0.01): AH Plus (4.77 +/- 0.85), Epiphany/hand mixed (3.06 +/- 1.34), Epiphany/automix syringe (2.68 +/- 1.35), and Apexit Plus (1.22 +/- 0.33). A significant difference (p < 0.01) was found among the dentin surface treatments. The highest adhesion values were obtained with AH Plus when root dentin was treated with Er: YAG laser and 17% EDTAC. Epiphany sealer presented the lowest adhesion values to root dentin treated with 17% EDTAC. Conclusions: The resin-based sealers had different adhesive behaviors, depending on the treatment of root canal walls. The mode of preparation of Epiphany (automix syringe or hand mixing) did not influence sealer adhesion to root dentin

Undergraduates&apos; opinion after 5-year experience with rotary endodontic instruments

Abstract Introduction: Dentistry evolution in the past few years has revolutionized daily practice in some specialties. One of these revolutions has occurred in Endodontics due to the advancement of rotary techniques for root canal preparation and its subsequent incorporation into the teaching of Dentistry undergraduates. Objective: The aim of this study was to report a 5-year experience on the undergraduate laboratorial and clinical use of rotary endodontic preparation at a private university. Material and methods: Data survey was performed by using a questionnaire composed of nine objective questions; the questionnaire was answered by the undergraduates. Results: The results showed a positive acceptance regarding the undergraduate teaching of the rotary technique (94.7%). The following advantages were highlighted: faster root canal preparation (91.6%) and reduction of patient&apos;s stress (80.9%). Conclusion: It can be concluded that the experience with the two undergraduate groups was excellent due to the high acceptance level of the new technique by the students