Sunil Mishra1, Ramesh Chowdhary. 1. Department of Maxillofacial Prosthodontics and Implantology, Dental College Azamgarh, Azamgarh, Uttar Pradesh, India.
Abstract
AIM: The present study is an in vitro study to evaluate the linear dimensional accuracy of commercially available polyvinyl siloxanes of varying viscosities using different impression techniques. METHODS: Different impression techniques used were: (a) putty wash, with a two-step technique with polyethylene spacer, using a stock tray; (b) putty wash, with a one-step technique, using a stock tray; (c) single-mix technique, utilizing medium viscosity in a custom tray; and (d) multiple-mix technique, utilizing a heavy- and low-viscosity combination in a custom tray. For each technique, 10 impressions were made of a metallic maxillary dentulous master model. RESULTS: The result of this study dictates that a heavy- and low-viscosity combination, double-mix technique in a custom tray produced an accurate result in all dimensions, followed by the single-mix technique, utilizing medium viscosity in a custom tray, and the putty wash two-step technique with polyethylene spacer, using a stock tray. Group 2 putty wash, one-step, simultaneous technique produced the least accurate result in all dimensions. CONCLUSION: The putty wash two-step techniques were found to be as accurate as the multiple-mix technique, utilizing a heavy- and low-viscosity combination in a custom tray, and the single-mix technique, utilizing medium viscosity in a custom tray. Making custom trays is time consuming and costly.
AIM: The present study is an in vitro study to evaluate the linear dimensional accuracy of commercially available polyvinyl siloxanes of varying viscosities using different impression techniques. METHODS: Different impression techniques used were: (a) putty wash, with a two-step technique with polyethylene spacer, using a stock tray; (b) putty wash, with a one-step technique, using a stock tray; (c) single-mix technique, utilizing medium viscosity in a custom tray; and (d) multiple-mix technique, utilizing a heavy- and low-viscosity combination in a custom tray. For each technique, 10 impressions were made of a metallic maxillary dentulous master model. RESULTS: The result of this study dictates that a heavy- and low-viscosity combination, double-mix technique in a custom tray produced an accurate result in all dimensions, followed by the single-mix technique, utilizing medium viscosity in a custom tray, and the putty wash two-step technique with polyethylene spacer, using a stock tray. Group 2 putty wash, one-step, simultaneous technique produced the least accurate result in all dimensions. CONCLUSION: The putty wash two-step techniques were found to be as accurate as the multiple-mix technique, utilizing a heavy- and low-viscosity combination in a custom tray, and the single-mix technique, utilizing medium viscosity in a custom tray. Making custom trays is time consuming and costly.
Authors: Michael S McCracken; David R Louis; Mark S Litaker; Helena M Minyé; Thomas Oates; Valeria V Gordan; Don G Marshall; Cyril Meyerowitz; Gregg H Gilbert Journal: J Prosthodont Date: 2017-01-11 Impact factor: 2.752