The present study will be done on children aged 3-9 years with extensive dental caries requiring full coverage restorations. A thorough clinical examination will be done for active dental caries using a plain dental mirror and explorer on the dental chair with optimal light, after which 45 primary teeth requiring crowns will be distributed randomly into three groups consisting of 15 participants in each: Group 1: Preformed Stainless-Steel crowns; Group 2: Preformed Zirconia crowns; Group 3: Preformed BioFlx crowns.

Informed consent will be obtained from parents or guardians of children participating in this study. Patients having extensive dental caries who require full coverage restoration will then be shortlisted, who will undergo either pulpotomy or pulpectomy procedure after which they will be randomly distributed into the above mentioned three groups for crown placement. The operator would be blinded to the type of the crown until the beginning of tooth preparation.

All the crowns will be clinically assessed by a single evaluator immediately after crown placement, at three months, six months and twelve months follow-up using United States Public Health Service (USPHS) criteria. The crown will be assessed for: the total time required for preparation, fitting and cementation; plaque accumulation; retention of the crown; tooth wear in opposing teeth; and radiographic findings.  The outcome assessor will be blinded at the data entry level to avoid bias. Also, at 12 months the parents will be asked to complete a simple six-item Likert scale questionnaire to evaluate their satisfaction with the procedure.