In vitro comparison of marginal and internal fit between stainless steel crowns and esthetic crowns of primary molars using different luting cements

BACKGROUND: This study was to assess and compare the marginal and internal fit of stainless steel crowns (SSCs) with those of preveneered SSCs and zirconia crowns using different luting cements. MATERIALS AND METHODS: In this in vitro study, 36 primary first molars were divided into three groups (n = 12) each prepared to receive different crowns (SSCs, preveneered SSCs, or zirconia crowns). Each group was further subgrouped (n = 4) according to the luting cement (resin cement, glass ionomer cement [GIC], or resin-modified GIC [RMGIC]). After cementation, the teeth were sectioned in the buccolingual direction to assess the marginal and internal fit. The results were analyzed using ANOVA and Bonferroni statistical tests. The level of significance was set at P < 0.05. RESULTS: Zirconia crowns, especially those cemented with resin cement, were associated with the lowest marginal and internal gap width. Regardless of the luting cement, no significant difference was observed between all three crowns tested in terms of marginal gap (P > 0.05); however, zirconia crowns cemented with resin cement had significantly lower internal gap than preveneered SSCs and SSCs cemented with resin cement. In addition, those cemented with RMGIC had significantly lower internal gap than preveneered SSCs cemented with that cement (P < 0.05). CONCLUSION: Zirconia crowns cemented with resin cement were the most accurately fitted internally, while marginally, they were not significantly different from the rest of crown-luting cement combinations tested.