A randomised controlled trial of three aesthetic full-coronal restorations in primary maxillary teeth

This randomised clinical trial (RCT) compared the clinical outcomes of three aesthetic full-coronal restorations (composite strip crowns, pre-veneered stainless steel crowns (SSCs) and pre-fabricated primary zirconia crowns) in carious and traumatised primary maxillary incisors.

One hundred and twenty nine teeth in 39 children aged between 3 to 5 years were included. Children were randomly assigned to one of three treatment groups using a permuted block randomisation technique with a total of 43 teeth in each group. After trainee calibration, restorations were placed and evaluated after 6 months. Outcomes evaluated were restoration failure, tooth wear of opposing teeth and gingival health.

The retention rate was highest for zirconia crowns (100%) followed by pre-veneered SSCs (95%). Strip crowns were the least retentive (78%). Zirconia crowns showed low grade abrasion in four opposing teeth. Teeth restored with resin composite and pre-veneered SSC showed an increase in mean gingival index score, while corresponding values decreased in zirconia crowns.

Resin composite strip crown is a highly sensitive technique leading to lower retention rate. Pre-veneered stainless steel crowns showed increased incidence of facial veneer fracture. Zirconia crowns are highly retentive and biocompatible but cause low grade of abrasion of their opposing natural dentition at the 6-month follow-up.