Treatment outcomes of preformed metal crowns placed with the conventional versus hall techniques: One-year randomized controlled trial results.

BACKGROUND

Preformed metal crowns (PMCs) have been used for decades to restore carious primary molars as they are extremely durable restorations. PMCs are delivered either by the traditional conventional technique (CT) or the more conservative Hall technique (HT)

OBJECTIVES

Assess the CT and the HT of PMC placement with regards to clinical outcomes and restoration survival after 12-months of the PMC restoration. The study also aimed to evaluate the occlusal vertical dimension (OVD) resolution following PMC placement by the HT.

METHODOLOGY: This study was designed as a non-inferiority, primary care-based, two-arm parallel group, randomized controlled trial. Eighty carious primary molars indicated for PMC restoration were randomly assigned into the CT and HT treatment groups. Standardized procedural techniques were followed in both the treatment groups to restore the carious primary molars with PMCs.

RESULTS

After 12-months of PMC placement, 73 of the 80 initially recruited trial participants returned for follow-up assessment. The clinical outcomes of all the PMC-restored teeth in both the CT and HT treatment groups were recognized as 'Successful' with none of the treated teeth experiencing any 'Major' or 'Minor' failures. All the PMC-restored primary molars in the CT and HT groups were functionally present at the 12-month follow-up (100% survival rate). The average increase in OVD immediately after crown placement by the HT was 1.18±0.68 mm. OVD reverted to its pre-treatment values within one-month of the PMC placement with no significant difference in OVD measurements at baseline and one-month after the HT PMC placement (P = 0.32).

CONCLUSIONS

Clinical success outcomes and restoration survival rates were similar for both the CT and HT of PMC placement.

CLINICAL SIGNIFICANCE: The non-invasive HT of placing PMCs to restore carious primary molars is a viable alternative to the traditional CT.