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.

A cephalometric analysis of Class II dentate subjects to establish a formula to determine the occlusal plane in Class II edentate subjects: A neo adjunct.

PURPOSE: Occlusal plane (OP) differs considerably in participants with skeletal Class I and Class II participants. In this study, cephalometrics has been used to help in the determination of orientation of the OP utilizing the nonresorbable bony anatomic landmarks in skeletal Class II participants and an attempt has been made to predict and examine the OP in individuals with skeletal class II jaw relationship. MATERIALS AND METHODS: One hundred dentulous participants with skeletal Class II malocclusion who came to the hospital for correcting their jaw relationship participated in the study. Their right lateral cephalogram was taken using standardized procedures, and all the tracings were manually done by a single trained examiner. The cephalograms which were taken for the diagnostic purpose were utilized for the study, and the patient was not exposed to any unnecessary radiation. The numerical values obtained from the cephalograms were subjected to statistical analysis. Pearson's correlation of <0.001 was considered significant, and a linear regression analysis was performed to determine a formula which would help in the determination of orientation of the OP in Class II edentulous participants. RESULTS: Pearson's correlation coefficient and linear regression analysis were performed, and a high correlation was found between A2 and (A2 + B2)/(B2 + C2) with "r" value of 0.5. A medium correlation was found between D2 and (D2 + E2)/(E2 + F2) with "r" value of 0.42. The formula obtained for posterior reference frame through linear regression equation was y = 0.018* × +0.459 and the formula obtained for anterior reference frame was y1 = 0.011* × 1 + 0.497. It was hypothesized that by substituting these formulae in the cephalogram obtained from the Class II edentate individual, the OP can be obtained and verified. CONCLUSION: It was concluded that cephalometrics can be useful in examining the orientation of OP in skeletal Class II participants.

An In vitro Study to Evaluate the Effect of Eugenol-free and Eugenol-containing Temporary Cements on the Bond Strength of Resin Cement and Considering Time as a Factor.

AIMS AND OBJECTIVES: The aim of this study was to assess the outcome of eugenol-free and eugenol-containing cements on the bond strength of resin cement. MATERIALS AND METHODS: Dentin was exposed in five groups of extracted teeth (20 specimens each). In Group 1, specimens were not given temporary cementation. In Groups 2 and 3, specimens were given temporary restoration fixed with eugenol-free temporary cement for 7 and 14 days, respectively. In Groups 4 and 5, specimens were given temporary restoration fixed with eugenol-containing temporary cement for 7 and 14 days, respectively. Permanent cementation was done for all groups after specified period of time. Shear bond strength testing of specimens was carried under universal testing machine. The data were analyzed by SPSS for Windows (version 14) statistical package (SPSS Inc., Chicago, IL, USA). RESULTS: One-way analysis of variance test revealed that Group 1 specimens produced higher shear bond strength than Groups 2, 3, 4, 5 and the difference was statistically significant (P < 0.001). In Groups 2, 3, 4, and 5, no significant difference in shear bond strength was observed between provisional restoration with eugenol-containing zinc oxide cement and provisional restoration with eugenol-free zinc oxide cement (P = 0.095). CONCLUSION: The findings of this in vitro experiment lend no support to the common opinion that eugenol-containing cements should be avoided as temporary cement.

Versatility of PEEK as a fixed partial denture framework.

Materials used for fixed partial denture (FPD) frameworks have had properties of excellent strength, durability, and biocompatibility. Some of the materials which have been used till date include alloys, ceramics, and high-performance polymers such as zirconia, Ni-Cr, lithium disilicate, and so on. All these, though excellent, have their advantages and disadvantages. Hence, the search has always been on for a better material. One such material, which has made its foray into dentistry in the recent times, is polyetheretherketone (PEEK). It is a semicrystalline thermoplastic material. PEEK has an excellent chemical resistance and mechanical properties that are retained at high temperatures. The versatility of PEEK as a dental material for FPD framework was evaluated in this case report.

Evaluating the fracture toughness and flexural strength of pressable dental ceramics: an in vitro study.

The study was undertaken to evaluate the biaxial flexural strength, biaxial flexural strength after etching with 9 % HF acid and fracture toughness of three commonly used pressable all ceramic core materials. Ninety glass ceramic specimens were fabricated from three commercially available leucite based core ceramic material (1) Esthetic Empress, (2) Cergo, and (3) Performance Plus. Thirty discs of each material were divided into three groups of 10 discs each. Biaxial flexural strength (30 discs,) Biaxial flexural strength for samples treated with 9 % HF acid (30 discs) and fracture toughness (30 discs) were evaluated. Core material Performance Plus had the lowest biaxial strength of 124.89 MPa, Cergo had strength of 152.22 MPa and the highest value of 163.95 was reported for Esthetic Empress. For samples treated 9 % HF, Performance Plus had the lowest biaxial strength of 98.37 MPa, Cergo had strength of 117.42 MPa and the highest value of 143.74 was reported for Esthetic Empress. Core material Performance Plus had the lowest fracture toughness of 1.063 MPa, Cergo had strength of 1.112 MPa and the highest value of 1.225 was reported for Esthetic Empress. The results shows that Esthetic Empress had better mechanical properties compared to Cergo had Performance Plus in relation to the parameters tested.

Laser gingival retraction: a quantitative assessment.

BACKGROUND: Proper gingival retraction improves the prognosis of crowns and bridges with sub gingival finishlines.Use of lasers assists the operator to achieve proper retraction with good clinical results. AIMS: The present study was intended to assess the amount of lateral gingival retraction achieved quantitatively by using diode lasers. SETTINGS AND DESIGN: Study was carried on 20 patients attended to a dental institution that underwent root canal treatment and indicated for fabrication of crowns. MATERIAL AND METHODS: Gingival retraction was carried out on 20 teeth and elastomeric impressions were obtained. Models retrieved from the impressions were sectioned and the lateral distance between finish line and the marginal gingival was measured using tool makers microscope. Retraction was measured in mid buccal, mesio buccal and disto buccal regions. STATISTICAL ANALYSIS: The values obtained were used to calculate the mean lateral retraction in microns. RESULTS: Mean retraction values of 399.5 µm, 445.5 µm and 422.5µm were obtained in mid buccal, mesio buccal and disto buccal regions respectively. CONCLUSIONS: Gingival Retraction achieved was closer to the thickness of sulcular epithelium and greater than the minimum required retraction of 200um.