Optical properties of esthetic temporary cements and final restoration color.

BACKGROUND: Opaque cements can be esthetically unfavorable and alternative translucent materials have been developed. The aim of this study was to evaluate the color interference of a new translucent cement compared with conventional materials, in association with interim restoration with different thickness and shades. METHODS: Bis-acryl composite disks were prepared in 2 thicknesses (1.2 mm, 0.6 mm) and 3 shades (A3.5, A2, bleached) to simulate the restorations. Cementation over dentin disks was performed with 1 translucent cement (Provicol QM Aesthetic; VOCO), 2 conventional cements (Provicol; VOCO, Temp-Bond NE; Kerr Dental), and 1 transparent liquid (polyethylene glycol 400). The difference between the color of the specimens cemented with the transparent liquid and that of the specimens cemented with each cement was calculated (ΔEab). The data were analyzed using 3-way analysis of variance and Tukey tests (5%). RESULTS: Significant differences were observed for all factors and some interactions (P < .05). For Provicol QM Aesthetic, the shade and thickness did not influence the ΔEab. For Provicol and Temp-Bond NE, the lighter and thinner the specimen, the higher the ΔEab. Only Provicol QM Aesthetic had smaller means than the perceptibility threshold. Temp-Bond NE and Provicol had higher values than the acceptability threshold for some combinations. CONCLUSIONS: The highly translucent cement had less color interference than the conventional materials. The thickness and resin shade only affected the results for the opaque cements. The thinner specimens and the lighter shades had higher color interference. PRACTICAL IMPLICATIONS: The use of a more translucent cement can produce a smaller color interference on the esthetic outcome of interim restorations.

Efficacy of Bracket Adhesive Remnant Removal by a Fluorescence-Aided Identification Technique with a UV Light Handpiece: In Vitro Study.

Objective: This study aims to analyze the fluorescence-aided identification technique efficacy on adhesive remnant removal from the enamel surface after orthodontic bracket debonding. Materials and Methods: Forty-five extracted human upper central incisors were divided into 3 groups (n = 15) according to the kind of adhesive for bracket bonding and the use or absence of near UV light for remnant removal: BF/UV- fluorescent adhesive/UV light, BF/0-fluorescent adhesive/no UV light, and TB/0-nonfluorescent adhesive/no UV light. For all teeth, 100% of the adhesive used remained on the enamel surface after debonding. Fifteen dentists performed adhesive removal on the enamel surface using a carbide bur. The specimens were analyzed by a stereomicroscope, and the adhesive remnant percentage from each specimen was calculated. The time used by each dentist to perform the removal was recorded. The data were analyzed by one-way ANOVA and Tukey's test. Results: Significant differences were observed among groups for adhesive remnant (p=0.0008) and for time (p=0.0001). The means of adhesive remnant were BF/UV (5.84), BF/0 (34.37), and TB/0 (37.02). The mean times necessary to remove adhesive were BF/UV (1 min 40 s), BF/0 (3 min 03 s), and TB/0 (2 min 46 s). For the BF/UV group, significantly lower values of adhesive remnants and time for debonding were found (p < 0.05). Conclusion: The fluorescence-aided identification technique significantly reduced the amount of adhesive remnant, and the time necessary to perform this clinical procedure.

Viscosity modulation of resin composites versus hand application on internal adaptation of restorations.

OBJECTIVE: To compare the effect of the injection of viscosity modulated resin composites versus hand application without modulation, on the internal adaptation of different material to the gingival wall of class II preparations. MATERIALS AND METHODS: Class II cavities were created on mesial and distal surfaces of 60 extracted human molars, resulting on 120 tooth preparations (n = 120). The preparations were restored with four resin composites: VIS-VisCalor (Voco); GRA-GrandioSO (Voco); FIL-Filtek One Bulk Fill (3 M/ESPE); and SON-SonicFill (Kerr). Each composite was applied by two different techniques: by hand (H) or assisted (A). For the hand technique, the material was placed into the preparation using a spatula. For the assisted technique, the resin composite was heated up to 65 °C (for VIS, GRA, and FIL) or sonicated (for SON) and injected into the preparation. After the restorative procedures, the teeth were completely demineralized to allow the restoration removal. The total area of the gingival wall and the area occupied by interfacial defects of adaptation (TDA) were measured by optical microscopy and digital software. The percentage of the area occupied by the defects (%TDA) in relation to the total area was calculated. The data were analyzed by two-way ANOVA and Tukey tests. RESULTS: Significant differences were observed for the application technique (p = 0.0403) and for the materials (p = 0.0184), as well for the interaction between them (p = 0.0452). The mean (standard deviation) of %TDA and results of Tukey test for the interaction were as follows: SON/H - 1.04(0.75)a; VIS/A - 2.01(0.92)a; VIS/H - 3.62(0.99)b; GRA/A - 6.23(3.32)b; FIL/H - 7.45(3.31)bc; GRA/H - 9.21(4.53)c; SON/A - 11.26(4.04)a; FIL/A - 17.89(5.08)d. CONCLUSION: The injection of heated resin composites improves the adaptation to the walls in relation to the hand technique for VisCalor and GrandioSO but worsens for Filtek One. Sonic vibration increases the number of interfacial defects for SonicFill. CLINICAL RELEVANCE: The physical modulation of the resin composite viscosity can improve or worsen the material adaptation to the walls of class II restoration. It had a positive impact for VisCalor and GrandioSO but a negative for Filtek One and SonicFill.

Efficacy of S-PRG filler varnishes on enamel caries remineralization.

OBJECTIVES: To evaluate the remineralizing effect of varnishes containing different concentrations of S-PRG filler or sodium fluoride on enamel caries lesions. METHODS: Enamel specimens were obtained from bovine incisors, flattened and polished. Half of the surface was protected, and artificial caries lesion was created in the unprotected area. They were assigned into six groups (n=20) according to the varnish applied: four containing S-PRG filler with different concentrations (10%, 20%, 30% and 40% w/w), one containing 5% sodium fluoride (5%NaF) as positive control, and one without treatment as a negative control (NC). Varnishes were applied on specimen's caries-affected surface and removed after 24 h. Varnish application and pH cycling (8 days) were performed twice. Cross-sectional microhardness was measured (10-100 µm depth). Knoop microhardness percentage (KHN%) of caries affected/treated area in relation to the sound enamel area at the same depth was calculated. The area under the curve (AUC) and the ΔAUC were also calculated. Statistical analysis was performed by two-way ANOVA for KHN% and one-way ANOVA for ΔAUC, followed by Tukey test (α=5%). RESULTS: Significant differences were found for the factors "treatment" (p=0.0001) and "depth" (p=0001). For the factor "treatment", the results of the Tukey test were: NC-62.2(10.3)a, 10%S-PRG-69.2(9.3)b, 20%S-PRG-71.8(9.7)bc, 30%S-PRG-74.5(9.4)c, 5%NaF-79.6(8.7)d, 40%S-PRG-85.6(8.4)e. In relation to ΔAUC, significant differences were observed among the groups (p=0.0001) and better results for 40% S-PRG and 5%NaF. CONCLUSIONS: The varnish containing 40% S-PRG fillers was the most effective to promote the enamel caries remineralization, followed by the one containing 5% sodium fluoride. CLINICAL SIGNIFICANCE: The varnish containing 40% of S-PRG fillers represents an alternative for initial enamel caries remineralization, since it was more effective than the conventional 5% NaF based product.

Efficacy of S-PRG filler containing varnishes on enamel demineralization prevention.

This study evaluated the efficacy of S-PRG vanishes on preventing enamel demineralization. Bovine enamel specimens were obtained, polished and the baseline Knoop microhardness was evaluated. Specimens were stratified into six groups (n = 15), according to the varnish applied: S10-experimental varnish containing 10% of S-PRG fillers, S20-20% of S-PRG fillers, S30-30% of S-PRG fillers; S40-40% of S-PRG fillers; PC (positive control)-5% of NaF; NC (negative control)-no treatment was performed. Half of enamel surfaces were protected to work as a control and varnishes were applied over the unprotected area. A demineralizing pH-cycling was performed, and surface and cross-sectional microhardness were measured. The percentage of microhardness of the treated area was calculated comparing with the untreated area. Statistical analysis was performed by one-way ANOVA and Tukey's test (p = 5%). All experimental S-PRG varnishes protected against demineralization in relation to no treatment, but S40 was the most effective on the surface. For all depths, S30 and S40 were superior in enamel demineralization prevention than other S-PRG filler concentrations and 5% NaF. It was concluded that S-RPG filler containing varnishes were effective to prevent enamel demineralization. The higher concentrated products were more effective than 5% sodium fluoride on surface demineralization prevention.

Influência do tipo de agente espessante e da viscosidade nas propriedades do gel clareador a base de peróxido de hidrogênio / Influence of thickener kind and hydrogen peroxide gel viscosity on the properties of the hydrogen peroxide gel

O estudo avaliou como o agente espessante e a viscosidade de um gel de peróxido de hidrogênio a 35%, podem influenciar o efeito clareador e as reações químicas que ocorrem dentro da camada de gel. Foram utilizados 540 dentes incisivos bovinos, dos quais 270 foram designados para obtenção de discos de esmalte e dentina para análise da cor. Os outros 270 dentes foram usados para as mensurações realizadas no gel. Géis clareadores experimentais (peróxido de hidrogênio 35% e pH 6.5) foram preparados com cinco agentes espessantes (CAR­ Carbopol; SA­ Salcare, ARI­ Aristoflex, CMC­ Carboximetilcelulose, AER­ Aerosil), para a obtenção de géis com viscosidades baixa (B - 50.000 cP), média (M - 250.000 cP) e alta (A ­ 1.000.000 cP). Além disso, três grupos controle foram preparados: CP (Controle positivo) - solução de peróxido sem espessante, CC (Controle comercial) - Whiteness HP (FGM); CN (Controle negativo) ­ água ultrapura. Os géis foram aplicados sobre o esmalte por 45 min. Foi avaliada a mudança de cor dos dentes, alterações na concentração de peróxido, pH e concentração de radicais livres. Os dados dos grupos experimentais foram analisados estatisticamente com ANOVA a 2 fatores (ESPESSANTE x VISCOSIDADE) e teste de Tukey. A comparação com os grupos controle foi realizada com o teste de Dunnett (a = 5%). Para todas as mensurações realizadas, a ANOVA mostrou diferenças significativas para os dois fatores (p <0,05). Para a mudança de cor (ΔE*ab), os resultado do teste de Tukey foram: ESPESSANTE - CMC 2.80(0.78)a, SA 2.81(0.8)a, AER 3.13(0.8)ab, CAR 3.24(1.05)ab, ARI 3.32(0.89)b; VISCOSIDADE - A 2.90(0.78)a, M 3.02(0.84)b, B 3.27(1.0)c. Para a concentração de peróxido os resultados foram: ESPESSANTE - CMC -4.86(1.85)a, AER -3.79(1.36)b, SA - 3.53(0.74)b, ARI -3.48(1.21)b, CAR -2.5(1.40)c; VISCOSIDADE - A -4.41(2.16)a, M - 3.26(0.91)b, B -3.23(0.92)b. Para o pH os resultados foram: ESPESSANTE - SA - 13.87(3.05)a, CAR -12.62(2.72)b, ARI -5.82(2.41)c, AER -4.94(1.42)d, CMC - 4.43(1.68)e; VISCOSIDADE - A -9.22(5.82)a, M -8.8(4.88)b, B -6.99(2.34)c. Para os radicais livres, os resultados foram: ESPESSANTE - SA 4.93a, CAR 6.83b, ARI 10.88c, AER 16.48d, CMC 29.76e; VISCOSIDADE - A 11.27a, M 13.82b, B 16.24c. A diferença significativa entre CN e os géis experimentais mostram a validação da metodologia e a eficiência do efeito clareador observado. A semelhança entre CC e géis experimentais demostram a capacidade de clareamento esperada para tal produto. Mediante esses resultados, podemos concluir que: o tipo de agente espessante e a viscosidade do gel clareador influenciam significativamente na interação do produto com o substrato dental e consequentemente na alteração de cor(AU)

The study evaluated how the thickening agent and the viscosity of a 35% hydrogen peroxide gel can influence the chemical reactions occurring inside the gel layer. 540 bovine incisors were used, from which 270 were used for color evaluation. The other 270 bovine incisors were used for gel changing evaluation. Experimental bleaching gels (hydrogen peroxide 35% and pH 6.5) were prepared using five thickening agents (CAR­ Carbopol; SA­ Salcare, ARI­ Aristoflex, CMC­ Carboxymethylcellulose, AER­ Aerosil), which were added to produce gels with low (L - 50.000 cP), medium (M - 250.000 cP) and high (H ­ 1.000.000 cP) viscosities. In addition, three control groups were prepared: PC (Positive Control) ­ a hydrogen peroxide solution; CC (Commercial Control) ­ Whiteness HP, FGM; NC (Negative Control) ­ purified water. The bleaching gels were applied for 45 minutes over the specimens. The evaluation were performed for color change, and concentration change of peroxide, pH and free radicals. Data were statistically analyzed with two-way ANOVA (THICKNER AND VISCOSITY) and Tukey Test. For control groups comparison Dunnett test was used ( = 5%). Significant differences were observed for both factors for all measurements performed (p <0,05). For color change (ΔE*ab) Tukey Test results were: THICKNER - CMC 2.80(0.78)a , SA 2.81(0.8)a , AER 3.13(0.8)ab, CAR 3.24(1.05)ab, ARI 3.32(0.89)b ; VISCOSITY - H 2.90(0.78)a , M 3.02(0.84)b , L 3.27(1.0)c . The results for peroxide concentration for THICKNER - CMC -4.86(1.85)a , AER -3.79(1.36)b , SA -3.53(0.74)b , ARI -3.48(1.21)b , CAR -2.5(1.40)c ; VISCOSITY - H -4.41(2.16)a , M -3.26(0.91)b , L -3.23(0.92)b . The results for pH for THICKNER - SA -13.87(3.05)a , CAR -12.62(2.72)b , ARI -5.82(2.41)c , AER -4.94(1.42)d , CMC -4.43(1.68)e ; VISCOSITY - H -9.22(5.82)a , M -8.8(4.88)b , L - 6.99(2.34)c . The results for free radicals for THICKNER - SA 4.93a , CAR 6.83b , ARI 10.88c , AER 16.48d , CMC 29.76e ; VISCOSITY - H 11.27a , M 13.82b , L 16.24c . The difference between NC and experimental groups certify the methods used and the efficiency of bleaching results. The similarity between CC and experimental groups results demonstrate the achievement of the expected bleaching result. Based on the results, it can be concluded that: The thickening agent and the gel viscosity significantly influence the product interaction with the dental structure and consequently on dental color(AU) ,