Proximal Contact Tightness of Zirconia Crowns: Digital Intraoral Scanning vs Conventional Impressions

Subjects will be randomly assigned in two groups using a computer generated randomization list. Allocated subjects in groups will be concealed in an envelope. All clinical procedures of crown preparation and cementation will be performed by a single clinician with standard crown preparation guidelines to minimize variability. After standardized tooth preparation for full coverage ceramic crowns, one group will receive conventional impressions using polyvinyl siloxane (PVS) material in trays and other group will be scanned using intra oral digital scanner. Crowns for both groups will be fabricated in the same dental laboratory under standardized conditions. Proximal and occlusal adjustments will be performed in the oral cavity before cementation at try in and crowns will be cemented using the same luting agent, GIC. After cementation proximal contact tightness will be assessed for the crowns by the digital force gauge at mesial and distal contacts and recorded for data compilation. The 0.05mm metal strip is inserted between the prosthesis and the adjacent natural tooth. The frictional force generated while removing the metal strip slowly in the buccal direction will be recorded on the screen of the customized digital force gauge. The frictional force generated will be considered equal to the proximal contact tightness and will be recorded in Newton (N). Proximal contact tightness will be recorded immediately after the crowns were cemented and at a recall after 10 days. These proximal contact tightness will be compared to see if there lies a significant difference in between the crowns fabricated from both impression techniques.