الفهرس 
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Abstract
This in vitro study investigated the dimensional accuracy of different elastomeric interocclusal relationship recording materials (VPS impression material, Polyether impression material, VPS bite registration material and polyether bite registration material) using two techniques of registration: 1) triple tray technique 2) injection technique of different edentulous conditions (fully dentate, one tooth missing and two teeth missing).
In the present investigation, 6 custom made epoxy resin models (3 upper and 3 lower models) were fabricated and mounted on a semi-adjustable articulator and a fixed force of closure was used to standardize the load during closure of the two compartments.
The maxillary custom made models were scored on top with a fixed distance between X and Y of 22 mm and 3 different points of intersection were made to measure the distance between them. The mean value of the distance transferred to the testing samples was measured at time intervals of 1 hour and 24 hours for each sample.
Data were collected from all the tests previously done according to the sample grouping in the form of tables of mean and standard deviations. The collected data were statistically analyzed.
Statistical analysis was performed by Microsoft Office 2013 (Excel) and Statistical Package for Social Science (SPSS) version 2d to 30.
Data were presented as mean and standard deviation (SD) values.
The significant level was set at P ≤ 0.05. Kolmogorov-Smirnova and Shapiro-Wilk tests were used to assess data normality and data was assumed normally distributed. Mixed ANOVA was used to assess effect of time, material, technique, and edentulous span over accuracy of bite registration.
The results of this study showed that there is no statistically significant effect of the elastomeric recording materials on the percentage of dimensional accuracy.
The time factor showed a statistically significant effect over dimensional changes of recording material where after 24 hours materials showed a significant effect on dimensional changes.
As regarding to technique and span length, the results showed no significant effect on dimensional accuracy. Although in this study, injection technique with VPS bite registration material show less significant effect on dimensional changes.