Evaluation of rotational resistance, rotational and vertical discrepancy of three different elastomeric impression materials with open tray implant level impression on a special model

The purpose of this study was to comparatively evaluate the rigidity and accuracy of three different elastomeric impression materials with an open tray implant level impression technique. In Part, I of the study a total of thirty open tray implant level impressions were made with vinylpolysiloxane (n=10), polyether (n=10), and vinylsiloxanether (n=10) impression materials. Implant replicas were connected to the impression coping using a digital screw torque checker. The peak torque values were recorded indicating the maximum rigidity of each group. The mean values were obtained and statistically analyzed using one-way ANOVA and Post-hoc HSD test. In Part II of the study, a total of thirty impressions were made with vinylpolysiloxane (n=10), polyether (n=10), and vinylsiloxanether (n=10) impression materials similarly. Implant replicas were connected to the impression coping with 5 Nㆍcm torque for vinylpolysiloxane and polyether groups. A gentle hand tightening was given to the vinylsiloxanether group. The master casts were poured. Subsequently, linear angle and vertical distance were measured using a coordinate measuring machine. The mean values were obtained and statistically analyzed using one-way ANOVA, posthoc Tukey HSD, and independent t test. Vinylpolysiloxane showed the maximum rotational resistance followed by polyether and the least by vinylsiloxanether and were statistically significant (P<0.05). Polyether showed the least rotational discrepancy than the vinyl polysiloxane and vinylsiloxanether and was statistically significant (P<0.05). Vinylpolysiloxane showed the least vertical discrepancy than the vinylsiloxanether and polyether without any statistical significance (P>0.05). Among the elastomeric impression materials used in this study, vinylpolysiloxane showed the maximum rotational resistance, polyether showed the least rotational discrepancy and the vertical discrepancy of these three materials was not significant.