Effect of cannabidiol oil on the color stability of resin composites.

PURPOSE: To evaluate the influence of cannabidiol (CBD) oil on the color stability of resin composites. METHODS: Three different resin composites were chosen to prepare 90 disk-shaped specimens. The specimens were randomly selected to compose two test groups (classic CBD or chocolate CBD) and one control group (distilled water) for a 14-day test. Two-way ANOVA was used to evaluate the influence of the CBD oil on the color stability of the three resin composites. Tukey post-hoc test (HSD) was used to determine the statistical difference among the groups. RESULTS: ANOVA indicated statistically significant differences among the storage solutions, resin composite, and their correlations (P< 0.001). HSD indicated significant differences among resin composites after staining. No difference was noticed between the color change of the specimens immersed in classic CBD or chocolate CBD. Color differences of the resin composites were related to the hydrophilic/hydrophobic nature of the resin matrix. CLINICAL SIGNIFICANCE: CBD oil affected the color stability of all the examined resin composite specimens. Considering the obtained results, appropriate guidance should be provided to patients to prevent potential color alteration owing to the usage of CBD oil.

Selección de color y reproducción en Odontología Parte 3: Escogencia del color de forma visual e instrumental

n este tercer y último artículo, estudiaremos los dos métodos de observación utilizados en la clínica odontológica: visual e instrumental. Para esto serán descritos las principales escalas e instrumentos utilizados en la selección cromática. También serán observadas las semejanzas y diferencias existentes entra la reproducción del color por técnica directa (con resinas compuestas) o por técnica indirecta (con sistemas cerámicos). Al final del artículo el lector podrá reconocer las indicaciones, ventajas y limitaciones de cada método.

n this third and final article, we will study the two methods of observation used in dental practice: visual and instrumental. The main scales and instruments used in color selection will be described. The similarities and differences between color reproduction by direct technique (composite resins) or by indirect technique (ceramic systems) will also be observed. At the end of the article the reader will be able to recognize the indications, advantages and limitations of each method.

Color stability of shade guides after autoclave sterilization.

This study evaluated the influence of 120 autoclave sterilization cycles on the color stability of two commercial shade guides (Vita Classical and Vita System 3D-Master). The specimens were evaluated by spectrophotometer before and after the sterilization cycles. The color was described using the three-dimensional CIELab system. The statistical analysis was performed in three chromaticity coordinates, before and after sterilization cycles, using the paired samples t test. All specimens became darker after autoclave sterilization cycles. However, specimens of Vita Classical became redder, while those of the Vita System 3D-Master became more yellow. Repeated cycles of autoclave sterilization caused statistically significant changes in the color coordinates of the two shade guides. However, these differences are considered clinically acceptable.

Translucency of value resin composites used to replace enamel in stratified composite restoration techniques.

BACKGROUND: The translucency of enamel shade is a crucial property that affects the color of a layered restoration. OBJECTIVE: This study evaluated the translucency of high-, medium-, and low-value resin composites (4 Seasons, Ivoclar Vivadent, Schaan, Liechtenstein) used to replace enamel in stratified composite restoration techniques. MATERIALS AND METHODS: The color specimens with 12 mm in diameter and various thicknesses (0.5, 1.0, 1.5, 2.0, 3.0, 4.0 mm) were measured after polymerization on a reflection spectrophotometer over white and black backgrounds to calculate the translucency parameter (TP). The statistical analysis of TP was accomplished using two-way analysis of variance (p < 0.05). Significant differences were revealed by the Tukey's Honestly Significant Difference post hoc test. RESULTS: Translucency of the value composite resins was influenced by the value and thickness. Color of value resin composites was dependent on the background contrast at the evaluated thicknesses. CONCLUSIONS: High-value composite resins were more translucent than medium-value composites, which were more translucent than low-value composites. The translucency decreased as the thickness of the specimens increased. CLINICAL SIGNIFICANCE: The results suggest that special attention should be paid to the thickness of the increment of value composite resins when reproducing translucency of natural tooth enamel.

Opalescence of bleached teeth.

OBJECTIVES: To evaluate the influence of tooth bleaching on the opalescence properties of enamel. METHODS: Color of 38 specimens was determined by colorimetric analysis before and after bleaching in the reflectance and transmittance modes. The results were described as CIELab color coordinates. The Opalescent Parameter (OP) was calculated as the difference in yellow-blue color coordinate (CIE Δb*) and red-green color coordinate (CIE Δa*) between the reflected and transmitted colors. RESULTS: Mean OP value of the specimens was 18.9 (±1.6) before bleaching and 16.1 (±1.0) after bleaching. CONCLUSIONS: Bleaching decreases the OP of the specimens (p>0.001). OP decrease was correlated with differences in b* color coordinate in the transmittance mode.

Resinas compostas para esmalte clareado podem diminuir a luminosidade do substrato nas técnicas restauradoras estratificadas / Marginal integrity analysis through three-dimensional scanner in silorane-based composites

Por meio de análise espectrofotométrica, este estudo avaliou a influência cromática de resinas compostas para esmalte clareado em substrato de resina composta para dentina A2. Sessenta e cinco corpos de prova foram confeccionados e divididos em um grupo controle (GC) e quatro grupos teste (G+cor da resina), da seguinte forma: a) GC, formado por resina para dentina (n=5); b) GXXL, formado por resina para dentina e resina para esmalte clareado XXL (n=15); c) GXL, formado por resina para dentina e resina para esmalte clareado XL (n=15); d) GL, formado por resina para dentina e resina para esmalte clareado L (n=15); e) GM, formado por resina para dentina e resina para esmalte clareado M (n=15). O incremento de resina para dentina acrescentou a espessura única de 2mm, enquanto o incremento de resina para esmalte clareado apresentou três diferentes espessuras, originando, em cada grupo teste, três subgrupos (S): a) S1, 1,2mm; b) S2, 0,8mm; c) S3, 0,4mm. A análise estatística foi realizada com ANOVA, que revelou diferenças significantes na luminosidade dos corpos de prova, conforme demonstrado por comparações feitas por meio do teste de Dunnett. Das quatro resinas para esmalte avaliadas apenas uma elevou a luminosidade do substrato. A aplicação dessas resinas provocou, em todos os grupos teste, alterações cromáticas consideradas clinicamente inaceitáveis (∆3>3,3).

The aim of this study was to perform a spectrophotometric analysis of chromatic influence of composite resins for bleached enamel on a A2-shaded composite resin substrate. Sixty five specimens were distributed in a Control Group (GC = dentin composite resin) and four test groups (GC + enamel composite shade) as following: a) GC, A2 shaded dentin composite resin (n=5); b) GXXL. GC and a composite for bleached enamel (XXL) (n=15); c) GXL, GC and a composite for bleached enamel (XL) (n=15); d ) GL, GC and a composite for bleached enamel (L) (n=15); e) GM, GC and a composite for bleached enamel (M) (n=15). The thickness of the dentin composite was 2,0mm, while the enamel composite presented three different thicknesses, originating three subgroups for each group (1.2mm, 0.8mm, and 0.4mm, i.e., S1, S2, and S3, respectively). Two-way ANOVA and Dunnett’s test for individual comparisons revealed statistically significant differences for luminosity. Only enamel composite increased the substrate luminosity. The application of bleached enamel composite resins resulted in clinically unacceptable chromatic changes in all test groups (Δ3>3.3).

Chromatic influence of value resin composites.

The current study evaluated the chromatic influence of high, medium and low value composites on a dentin composite substrate (A2 shade) using spectrophotometric analysis. The specimens were divided into the following four groups: a) control (CG), entirely composed of dentin composite (n = 5); b) high value (GHV), dentin composite and high value composite (n = 20); c) medium value (GMV), dentin composite and medium value composite (n = 20) and d) low value (GLV), dentin composite and low value composite (n = 20). The dentin composite was 2.0 mm thick and the value composite was added in four different thicknesses, dividing the groups into four subgroups: S1 = 1.0 mm, S2 = 0.8 mm, S3 = 0.6 mm and S4 = 0.4 mm. The results were determined using the CIELAB system and differences in brightness of the specimens were analyzed using two-way ANOVA. Significant differences were found between different value resin composites, thicknesses and interactions, as revealed by the Tukey's test (HSD). Adding value composite produced lower brightness, and a gray shade was observed, compared to the control, regardless of the value or thickness of the primary composite. Eleven of the 12 subgroups presented clinically unacceptable chromatic changes, except when the 0.4 mm thickness of high value composite was used.