Objectives:This study was planned to evaluate the dimensional stability of elastomers during cold sterilization or immersion disinfection and also to evaluate the same, along with acrylic resin trays which are used in clinical practice.Materials and Methods:A study mold according to revised American Dental Association. Specification no. 19 was used. Polyether, polyvinyl siloxane (PVS) (heavy body), PVS (regular body) and Hydrophilic addition reaction silicon (medium body) were selected for study. 2% glutaraldehyde and 0.525% sodium hypochlorite were the disinfectants used. The study was divided into group-I and group-II. In group-I study, 24 specimens of each impression material were prepared. Eight immersed in 2% glutaraldehyde, eight in 0.525% sodium hypochlorite and rest eight allowed to dry bench cure. After 16 h, the specimens measured under Leica WILD stereomicroscope and dimensions compared with master die. In group II study, 24 specimens of the material with the least dimensional changes were prepared and adhered to 24 acrylic resin disks using tray adhesive. Same immersion procedure was followed as in group I. The data were analyzed by one-way ANOVA and Tukey's multiple tests.Results:Of four impression materials used, PVS (heavy body) was the most dimensionally stable, and Polyether was the least dimensionally stable in both the groups.Interpretation and Conclusion:Within the limitation of the study, PVS (heavy body) was most stable, and polyether was least stable of all the impression materials.

Background The most common complaint following cementation is the occurrence of post cementation sensitivity. The sensitivity to cold stimulus after cementation can be indicative of a gap present below the crown or a marginal gap connecting to opened tubules which emerge into the pulp. A pulp fluid outflow occurs as a result of the contraction of dentinal fluid in this gap which causes postoperative sensitivity. Thus luting agents should form complete seal between fabricated restoration and prepared tooth.Objectives The current study was conducted to clinically evaluate post-cementation hypersensitivity of bioactive luting cement in a randomized clinical control trial using resin modified glass ionomer cement RMGIC as the control.Methods According to standard tooth preparation protocol the teeth were prepared to receive Porcelain fused to metal PFM bridges on both sides of the mouth. PFM final restorations were cemented using Bioactive and RMGIC luting cement. Sensitivity was tested by using compressed airbiting pressure tests and cold water and was evaluated by using Schiff scale with 0-3 scores before cementation soon after cementation one week and three months post cementation.Results Almost all the patients responded to hypersensitivity at pre-cementation and baseline with compressed airbiting pressure tests and cold water. The sensitivity scores reduced over time one week and three months for both the luting agents.Conclusion Based on the results it can be concluded that the bioactive luting cement exhibited lesser sensitivity scores when compared to resin modified GIC luting cement.

Background: Wax-ball centric relation technique is a novel, fast, dentist and patient friendly method of registration of centric position during establishment of jaw relation. Objective: To compare Wax Ball centric registration technique with Gothic arch tracing and record the deviations in recording Wax Ball centric registration technique compared to Gothic arch tracing. Materials and Methods: In a Clinical setting, comparative clinical Trial was conducted among a random sample of 20 elderly patients aged 30-60 years old, centric relation was recorded and compared using Wax Ball and Gothic arch tracing methods. The deviations observed with Wax ball technique compared to Gothic arch tracing method were recorded. Cohen's Kappa test was applied to test the level of agreement between the techniques.Results: Out of the total 20 recordings of wax ball technique, 10 recordings showed deviations (Anterior -3, Posterior-7). The mean deviation was 0.6±0.5mm (Range 0-2mm). Mean anterior deviation was 1.16±0.7mm and mean posterior deviation was 0.92±0.34mm. There was fair agreement between the two methods. (66.66%-agreement, Cohen's Kappa value=0.39). Conclusion: Wax-ball centric relation technique could be a useful, fast and user-friendly method to record centric position.

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