A number of materials are available to protect the pulp from postoperative sensitivity. The effect of a calcium hydroxide liner and a dentinal desensitizing agent (potassium oxalate) on crown retention was investigated. Gold crowns were cemented on standardized crown preparations with zinc phosphate cement, glass-ionomer cement, or one of two resin cements. A tensile force was applied until separation occurred. The mean applied force at rupture varied greatly among the groups, indicating that the pulpal protection agent may have a distinct effect on the retention of cast restorations. In addition, other clinical factors, such as angle of convergence, crown height, and total surface area of the tooth should be considered.