Full coverage crowns for rehabilitation of MIH affected molars: 24 month randomized clinical trial

Teeth affected with severe molar incisor hypomineralization (MIH) require extensive restorations, which do not last for a long time and often require treatment in the form of onlays or full coverage restorations.

To evaluate and compare the clinical performance of zirconia, lithium disilicate, and cast metal crowns as full-coverage restorations on MIH-affected first permanent molars (FPMs).

60 MIH affected FPMs requiring full-coverage crowns were identified in children aged 8-15 years and were randomly allocated to the three treatment groups according to the type of full coverage restoration received using block randomization technique. After an adequate removal of the MIH defect and restoration with composite resin, the tooth preparation was done followed by fabrication of crown and its cementation using resin cement. The intergroup comparison was done on the basis of USPHS criteria, gingival, plaque scores, patient and parents acceptance through a visual analog scale to decipher their clinical performance at 6, 12, 24 months.

After 24 months, the crowns showed similar clinical success in terms of the criterias used to compare their clinical performance. The retention, marginal adaptation, relief from hypersensitivity, proximal contact, gingival health with no statistically significant difference among the three groups.

Based on the observations, Lithium disilicate, Zirconia and full cast metal crowns showed similar clinical success in rehabilitation of First permanent molars with severe MIH over 24 months of evaluation. The clinical success is not influenced by the material of the restoration. However, prospective studies with a longer follow-up are required to reach a more definitive conclusion.