Detail reproduction, contact angles, and die hardness of elastomeric impression and gypsum die material combinations

Purpose: This study compared surface detail parameters, interfacial contact angles, and die hardness for some combinations of elastomeric impression a nd die materials. Materials and Methods: Representative polyvinyl siloxanes , polyether, polysulfide, and reversible hydrocolloid impression materials and Type IV, Type V, and resin reinforced-Type IV die materials were evalua ted using a factorial design. For the evaluation of surface detail reproduc tion, the width of the thinnest continuous line observed and the visually o bserved shape of the thick line were determined from samples formed using a master die conforming to American Dental Association specification 19. The contact angle of freshly mixed die material on the set impression was meas ured using a contact angle goniometer. Finally, hardness of the die materia l was determined. After conversion of the data to ranks if necessary, 2-way analysis of variance with Ryan-Einot-Gabriel-Welsch (REGWQ) multiple compa rison tests where appropriate were used to determine statistical significan ce. Results: The thinnest continuous line demonstrated statistically signif icant impression material effects, and the observed shape of the thick line showed both statistically significant impression material and die material effects. For both contact angle and die hardness, a statistically signific ant interaction between the impression and die materials was found. Conclus ion: Although statistically significant differences in each property were f ound, no specific combination of impression and die materials was identifie d as superior to another for all surface properties studied.