Comparative evaluation of effect of auxiliary retentive features on retention of complete cast crowns in teeth with adequate and inadequate crown height. An invitro study.

This study was done to evaluate the retention of complete cast crowns in teeth with adequate and inadequate crown height and to evaluate the effects of auxiliary retentive features on retention from of complete cast crowns. Thirty-six extracted human maxillary first premolars were obtained. In one group teeth were prepared to a constant height of 3.5 mm and in the second group teeth were prepared to a constant height of 2.5 mm. Each group was further subgrouped into three. In the first subgroup teeth were prepared conventionally, second subgroup proximal grooves were incorporated and in the third subgroup proximal boxes were incorporated. Tensional forces required to dislodge each cemented casting from its preparation was used for comparison of retention quality. These results were then subjected to an analysis of variance (ANOVA). The retention of crown in tooth with adequate crown height were statistically highly significant (P < 0001), compared to inadequate crown height and in boxes compared to grooves and conventional preparation.