Effect of Two Different Impression Techniques on Fit Accuracy of Cad/Cam Post and Core Restorations (In Vitro Study)

Abstract

INTRODUCTION:Endodontically treated teeth restoration is a challenging dental procedure. Restored teeth failure threshold is mainly related to posts to root canals adaptation. OBJECTIVE: To examine the consequence of using two different intracanal impression techniques on the accuracy of fit of CAD/CAM hybrid ceramic post and core restorations. MATERIALS AND METHODS: Twenty mandibular first premolars were chosen then endodontically treated and prepared for receiving post and core restorations. The specimens were randomized into two equal groups: CAD/CAM post and core restorations for group I were obtained by scanning the auto polymerizing acrylic resin pattern. For group II polyvinylsiloxane impressions of the post space were scanned. Post and core restorations were milled and cemented on their respective teeth. All of the 20 specimens were then sectioned longitudinally and the post and core adaptation were evaluated using the stereomicroscope. RESULTS: With the impression scanning technique, the overall space that was made between the canal walls and posts ranged between 72.93 -135.62 μm, with a mean value of 96.21 ± 18.44 μm, whereas with the acrylic pattern scanning technique, the space ranged between 105.57 -126.91 μm, with a mean of 115.52 ± 7.51 μm. CONCLUSIONS: For the manufacture of hybrid ceramic post and core restorations, the impression scanning technique achieved better fit and higher accuracy than the acrylic pattern scanning technique.