Deformation of crowns during cementation

• Published in: The Journal of prosthetic dentistry Vol. 64; no. 5; pp. 601 - 609
• Main Authors: Wilson, Peter R., Goodkind, Richard J., Delong, Ralph, Sakaguchi, Ronald
• Format: Journal Article
• Language: English
• Published: United States Mosby, Inc 01.11.1990
• Subjects: Acid Etching, Dental; Analysis of Variance; Cementation; Crowns; Dental Cavity Preparation; Dental Stress Analysis; Dentistry; Denture Design; Gold Alloys - chemistry; Stainless Steel; Stress, Mechanical; Surface Properties; Viscosity; Zinc Phosphate Cement - chemistry
• ISSN: 0022-3913; 1097-6841
• DOI: 10.1016/0022-3913(90)90136-Z

Deformation of crowns during cementation was investigated by a simple loading system of defined crowns with silicone fluids as cements. Deformation of the crowns was measured by long strain gauges that encircled the cervical margins. Die spacing was simulated by etching the die. Venting was simulated by removing a small screw. Deformation of the crowns was decreased by decreasing the viscosity of fluid, increasing the thickness of the crowns, and venting. Etching the die decreased the seating times of the crowns, but did not alter the level of deformation. Terminal cementation with zinc phosphate cement confirmed the presence of crown deformation during cementation. The results have consequences for bonded and all-ceramic crowns, and explain several clinical phenomena. It is suggested that low viscosity cements, low seating forces, and die spacing be used to decrease the deformation of crowns during seating. The importance of passive fitting of the crown to the tooth is stressed.