T 1 he cast dowel and core has been successfully used as a foundation for the restoration of nonvital teeth for many years. Lack of retention, structural failure of the dowel itself, or fracture of the remaining tooth structure are probable causes for clinical failure. Retention is dependent on several factors including dowel length, diameter, shape, surface irregularity, and cementation medium.‘” Parallel-sided, cylindrical dowels of maximum length containing surface irregularities or serrations appear to offer the greatest retention.3,5 Increasing both the diameter and depth of channels in dentin to maximize retention of a dowel also increases the risk of lateral perforation and fracture of the remaining tooth structure. Structural failure of the dowel includes fracture and distortion, depending on the physical properties of the metal. The structural durability may be altered by changing the diameter or shape of the dowel or by selecting a metal that exhibits improved physical properties. Recently base metal alloys have been suggested for cast dowels and cores.‘n8 The physical properties and comparatively low cost offer advantages over the gold alloys. In addition, the development of the resin-bonded, electrolytically etched cast metal technique and the introduction of dentinal bonding agents offer the potential for increasing the retention of dowel restorations.‘.” This study compared the retention of electrolytically etched, cast base metal dowels cemented with a resin cement, with and without the use of a dentinal bonding agent, to cast gold alloy dowels cemented with zinc phosphate cement. The effect of reducing dowel length on retention was also evaluated.