Comparative evaluation of flow profile of commercially available vinyl polysiloxane impression materials - An in-vitro study.

Background: Flow characteristics of vinyl polysiloxane (VPS) impression materials are important determinants in the selection of impression materials for the fabrication of accurate indirect restorations. Aims: : The purpose of this study was to determine the flow of three commercially available VPS impression materials at different time intervals using a shark fin device (3M ESPE, Seefeld, Germany). Study Setting and Design: This in-vitro study was carried out at the prosthodontics department of a dental institution. Methods and Material: The height of the shark fin produced by each impression material determined the rate of flow. Statistical Analysis: The data were analysed using one-way analysis of variance (ANOVA) and post-hoc Tukey's test (p-0.05). Results: : Shark fin height of group A VPS impression material was significantly higher at 30 and 120 seconds compared to group B and group C VPS impression materials. Shark fin height produced by group B VPS impression materials at 60 and 90 seconds was significantly higher than the group C VPS impression material but non-significant compared to group A. At 120 seconds, there was no significant difference in the shark fin heights of all the tested materials. Conclusion: All the materials exhibited adequate flow characteristics within clinically acceptable limits.

Instructional Design for Assessment of Dental Esthetic Treatment Needs in a Indian Undergraduate School: A Randomised Controlled Trial.

In the recent years esthetic dentistry has been the area of focus amongst the public. Esthetics is an important dimension in dental practice and the upcoming dentists need to be enabled to demonstrate their competencies for an efficient clinical outcome. The purpose of this study was to institute a cultural change within traditional didactic dental education towards student centred learning to cope up with the accelerating pace of medical technological change and achieving positive impact on patient care and patient satisfaction. Intervention that was considered for the project included David Merrill's first principles of instruction. A randomized controlled trial was conducted with all the students from four cohorts of final year dental undergraduate students, divided into an intervention group (n = 40) and a control group (n = 40). A professional assessment questionnaire is used to evaluate the relationship between the students and professional's assessment of esthetic treatment needs. The results of the study indicated that the ranking of the most and least noticeable dental features differed significantly (p = 0.0061) between the intervention and non intervention group and the indicates the intervention group to be in better agreement with professional assessment than the non intervention group of students with z value of 2.7435. The relative agreement between intervention group of undergraduate students and the professional assessment of esthetic treatment need shows the importance of intervention of Merrill's first principles of instruction in learning, emphasising the significance of PBL and therefore indicating a positive impact on successful esthetic treatment for patients.