Influence of Different Enamel Shades and Thickness on Chroma and Value of Dentin Vita Shade: An in vitro Comparative Assessment Study.

BACKGROUND: The aim of the present study is to determine the influence of different enamel shades of various thickness on chroma and value of vita shade of dentin. MATERIALS AND METHODS: Three enamel composite resin shades (Enamel white, grey and neutral) and one dentin shade (A 2) from A melogen Plus (Ultradent) was used. Ninety Enamel disk specimens of 0.5, 0.75 and 1 mm thickness and 10 mm in diameter for each shade and 90 dentin disk specimens of 2 mm in thickness and 10 mm in diameter was used for the study. The spectrophotometric values of the dentin shade with and without enamel specimens were recorded and the values were converted to CIEL*a*b values. RESULTS: Statistical analysis was done using Pearson correlation coefficients to verify the effect of thickness on Chroma and value, and the significance was evaluated by one-way ANOVA and Tukey post hoc test. Two way ANOVA and Tukey post hoc was done to verify the variation within the groups. Results revealed a significant positive correlation between thickness and chroma and a negative correlation between thickness and value. There was a statistically significant variation in between the groups. CONCLUSION: All groups produced a significant increase in chroma with increase in thickness of enamel shade upto a thickness of 0.75 mm after which the behavior of each shade was erratic. Hence, the optimum thickness would be 0.75 mm. All groups produced a significant decrease in value with increase in thickness of enamel shade. Enamel white produced the greatest reduction in value, enamel neutral the least and enamel grey demonstrated an intermediate result. CLINICAL SIGNIFICANCE: There is a need to have a knowledge of the effect on chroma and value when dentin is layered with different enamel shades, it is also important to understand the effect of these enamel shades at different thicknesses to better control the color and reproduce esthetic simulating natural teeth.

A comparative evaluation of antimicrobial efficacy and flow characteristics of two epoxy resin-based sealers-AH plus and Perma Evolution: An in vitro study.

AIM OF THE STUDY: Bacteria that persist at the time of obturation increase the possibility of persistent apical periodontitis. An ideal sealer should be able to kill these remaining bacteria that are present on the dentinal walls as well as inside the dentinal tubules. This could be possible if a sealer has antimicrobial properties with optimum flow characteristics. Hence, the aim of this in vitro study was to assess the antimicrobial efficacy of epoxy resin-based sealer: AH Plus and Perma Evolution against Enterococcus faecalis on the 1st, 3rd, 5th, and 7th day and also to compare the flow characteristics of both epoxy resin-based sealers. MATERIALS AND METHODS: E. faecalis ATCC 35550 strain was used to assess the antibacterial efficacy of sealers by agar-diffusion test (ADT) and direct-contact test (DCT). Flow characteristics of sealers were measured according to the ADA specification no. 57. RESULTS: In ADT, Perma Evolution sealer showed larger zone of inhibition than AH plus on the 1st, 3rd, 5th, and 7th day, and in DCT, both sealers were equally effective in inhibiting E. faecalis growth on the 1st, 3rd, 5th, and 7th day. Flow test showed no significant difference between Perma Evolution and AH Plus sealer. CONCLUSION: Both the tested sealers were equally effective against E. faecalis up to 7 days of incubation period. Considering flow properties, both the tested sealers showed optimum flow as per the ADA specification no. 57.

The efficiency of root canal disinfection using a diode laser: in vitro study.

AIMS: The aim of this study is to verify the disinfection of diode laser, following chemo-mechanical procedures against Enterococcus fecalis. MATERIALS AND METHODS: Crowns of 30 extracted premolar teeth were sectioned at the cemento- enamel junction. The canals were shaped using step-back technique to K-file #40. The teeth were randomly assigned to three groups and placed into nutrient broth containing bacterial suspension of Enterococcus fecalis. Group A received no laser radiation. Specimens of group B and C were treated with diode laser (Sirona) with energy set at 1.5 and 3 W, respectively. After laser irradiation, the teeth were placed in vials, which contained 2 mL of the nutrient broth. The vials were incubated at 37°C for 24 h. Grown colonies were identified by standard methods. STATISTICAL ANALYSIS USED: Statistical analysis used was the nonparametric Kruskal-Wallis test, with comparison using the Bonferroni methods of means. RESULTS: Higher mean CFU/mL is recorded in Group A (without laser disinfection) followed by Group B (with 1.5 W laser disinfection) and Group C (with 3 W laser disinfection), respectively. The difference in CFU/mL between the three groups is found to be statistically significant ( P < 0.001). CONCLUSIONS: The results of this research show that the 980 nm diode laser can eliminate bacteria that has immigrated into dentin, thus being able to increase the success rate in endodontic therapy.