Impression Technique / Tissue Retraction Combinations: Effect on Marginal Integrity of Fixed Prosthesis

The purpose of this study was to clinically assess the precision of margins reproduction using some impression techniques following application of different retraction materials. A PVS impression material with different viscosities and an injectable tissue retraction material were chosen to make impression using two impression techniques. Traditional retraction cord was used as a control. A number of patients requiring fixed prostheses were selected and a total of twenty impressions were obtained following tissue retraction with special trays. Impressions were made using different combinations of two impression techniques and two retraction materials, which resulted in four groups of five each. Margin integrity was evaluated subjectively with naked eyes and X10 stereomicroscope by three clinicians, according to an ordinal scale from 1-3 depending on the presence of emergence profile on the circumference of the margins (COM) of the prepared teeth. It was found, generally, that recorded margins did not differ significantly with variation. It can be concluded that using different combinations of tissue retraction materials and impression techniques show no significant clinical differences from each other.