Comparative evaluation of the effect of degree of convergence and surface area on the retentive force of titanium crowns cemented with various adhesive luting agents on extracted human teeth – A laboratory study

Introduction: The retention of base metal crowns and noble metal crowns cemented with various luting agents is well documented. However, little emphasis was given to the degree of convergence and surface area of tooth preparation. Aim and Objective: A study was planned to analyze the effect of the degree of convergence and surface area of the tooth preparation on the retention of titanium crowns with various adhesive luting agents. Materials and Methods: Forty-five caries-free extracted human premolars were obtained. They were divided into three groups according to the degree of convergence and further subdivided based on the type of luting agents used. The teeth were prepared with an angle of convergence of 5°, 10°, and 15° with a flat occlusal surface using K9 crown finishing installation, complete. Light body copper band impressions were made to determine the surface area. Titanium crowns thus obtained were sandblasted, ultrasonically cleaned, and cemented using Panavia F, Calibra, and Glass Ionomer Cement. Results: Results showed that Panavia F was the best luting agent exhibiting maximum retentive force to dislodge the crown in a vertical direction using the universal tensile testing machine at a cross-head speed of 1 mm/min. Conclusion: The force required to dislodge the titanium crown from the prepared tooth was maximum for Panavia F on 5°, 10°, and 15° angle of convergence at 65.23 kgf, 48.52 kgf, and 40.14 kgf. Retentive force values drastically reduced as the degree of convergence increased. There was a reduction in the surface area due to an increase in the taper.