Effectiveness of denture cleansers on flexible denture base resins in the removal of stains colored by food colorant solution: An in vitro study.

Aim: The aim of the study was to compare the efficiency of three denture cleansers (Valclean, Polident and Clinsodent) in removal of turmeric stains from flexible denture base resins. Settings and Design: In vitro - comparative study. Materials and Methods: A total of 45 specimens of flexible denture base resins were fabricated and subjected to baseline colour measurements using spectrophotometer. Specimens were stained with turmeric and colour measurements of stained specimens were made. All the stained specimens were divided into three groups (n = 15) for removal of stains with three denture cleansers: Valclean, Polident, Clinsodent and colour measurements of cleansed specimens were made. The colour measurements (ΔE) values obtained were collected and statistical analysis was done. Statistical Analysis Used: One-way ANOVA (Analysis of Variance), Tukey's post hoc test. Results: One way ANOVA test revealed that the mean colour difference of three groups were statistically different with P value < 0.001. A further Tukey post hoc test revealed that the Valclean group had lesser mean scores than Polident and Clinsodent group. Conclusion: It was concluded that Valclean showed statistically significant greater stain removal efficiency than Polident followed by Clinsodent.

Comparative evaluation of enamel wear against monolithic zirconia and layered zirconia after polishing and glazing: An in vitro study.

Aim: The aim of this study was to compare the wear behavior of human tooth enamel opposing monolithic zirconia and layered zirconia after glazing and polishing by a two-body wear mechanism using a wear simulator. Settings and Design: This In-vitro study was done in Department of Prosthodontics, Sri Sai College of Dental Research, Vikarabad. Materials and Methods: Zirconia specimens were divided into four groups (n = 15), Group monolithic glazed zirconia (MG), Group monolithic polished zirconia (MP), Group zirconia layered with E. max ceram and glazed (LG), Group zirconia layered with E. max ceram and polished without glaze (LP). Sixty human premolar teeth were subjected to wear test against the zirconia specimens using a Pin on Disc wear tester under a constant load of 5 kg (49 N) at 30 rpm for 10,000 cycles. The loss of enamel was recorded before and after the wear test and mean loss of height of tooth enamel after 10,000 cycles of wear was measured with a profile projector. The surface characteristics of all the four group zirconia specimens were evaluated qualitatively with scanning electron microscope. Statistical Analysis Used: One way ANOVA, Tukey Post hoc. Results: One-way analysis of variance test revealed that the mean loss of enamel of four groups was statistically different with P < 0.001. A further Tukey post hoc test revealed that the MP group had lesser mean scores than group LP, MG, and LG. Conclusion: It was concluded that MP caused less wear to opposing natural teeth, and polished surfaces of both monolithic and layered zirconia showed less tooth wear compared to glazed surfaces of monolithic and layered zirconia.

Evaluation of flexural strength of Zirconia using three different connector designs: An in vitro study.

AIM: The aim of this study is to evaluate the flexural strength of zirconia using three different connector designs under vertical and oblique loads. SETTING AND DESIGN: Invitro - analytical study. MATERIALS AND METHODS: For simulating zirconia fixed partial prosthesis, a specimen with three octagonal cylinders connected with each other was designed. Each face of the octagon was 3.75 mm ± 0.1 mm, and the total width was 9 mm ± 0.1 mm with a standard connector area of 10 mm2 at cross-section. Three different connector designs, i.e., round, oval, and triangular were milled. Universal testing machine was used to test flexural strength with vertical and oblique forces. STATISTICAL ANALYSIS USED: Intergroup comparison of flexural strength was made using Descriptive statistics (1) one-way ANOVA, Bonferroni's post hoc test (2) Kruskal-Wallis test. The confidence interval was set at 95%, P < 0.05 was considered statistically significant for both the tests. RESULTS: The highest flexural strength was observed in the triangle connector with vertical forces and lowest with oblique forces. CONCLUSIONS: Triangle connector design proved to be better than round and oval connectors on the application of vertical loads. Round connector design proved to be better than triangle and oval connector on application of oblique loads.