The effects of time elapse, desinfection solutions and preservation places on dimensions of Duralay acrylic pattern

There is a wide clinical application of Duralay acrylic resin pattern for direct post and core fabrication. As the effect of time elapse, desinfection solution and preservation places is not studied together, this study was designed to evaluate the interaction of these variables on dimensions (length, coronal and apical diameters) of duralay acrylic resin patterns. Methods & Materias: In this in vitro and quasi experimental study 36 duralay patterns fabricated in simulation method were used. Then patterns were categorized in one of the 3 groups of glutaraldehyde, sodium hypochloride and control. Each group of 12 patterns was divided in the two groups of preservation places (wet and dry). Patterns were measured in time intervals of 0, 1, 3, 6, 9, 24 hours. The 3 dimensions of length and apical and coronal diameter were measured with digital micrometer with 10 microten accuracy. Statistical analysis demonstrated that coronal and apical diameters differ significantly by the effect of time elapse and disinfection solutions and preservation places (P<0.005). Coronal diameter demonstrated significant difference as the effect of time elapse. (P<0.005) Significant differences were not noted between wet or dry preservation places. Glutaraldehyde caused contraction and sodium hypochloride caused expansion of duralay patterns. The mechanism of this different effect was not understood. It was observed that linear dimensional change of duralay acrylic patterns didn’t follow a linear correlation formula for prediction of duralay changes and the best time for casting. Different effects of desinfection solution on casting and cementation stages must be evaluated to achieve better evidence and clinical relevance.