This study aims to compare the clinical performance of Prefabricated Zirconia Crowns (PZCs) with that of Custom-made Zirconia Crowns (CZCs) using enhanced clinical protocols.

Young permanent molars presenting with gross caries, pulpal treatment or developmental defects often require full coverage restorations. Recently, the Prefabricated Zirconia Crowns (PZCs) have been introduced as a biocompatible and an aesthetically pleasant option with promising outcomes. However, it comes in specific sizes, limited shades and a significant tooth preparation is often required. Custom-made zirconia crowns (CZCs), fabricated using CAD/CAM technology may; offer a favorable aesthetic alternative by ensuring a controlled tooth reduction, precise fit, better aesthetics, and improved retention. Nevertheless, the current evidence concerning its use in young permanent molars remains limited. This study will be a randomised clinical trial that aims to compare the clinical performance of (PZCs) with that of (CZCs) for the restoration of badly carious/destructed young permanent molars in children aged 7-13. Patients will be randomised into two treatment groups using an online block randomisation technique (block size of 6) and sealed-envelope techniques. Clinical parameters: retention, fracture, gingival health and marginal integrity will be evaluated at 3-month, 6-month, and 12-month intervals. In addition, treatment duration, intraoperative patient comfort and immediate postoperative patient satisfaction will be evaluated and compared. The findings of this study are expected to provide evidence on the suitability of CZC for young permanent molars in children. The Null hypothesis is that there is no difference between the two types of crowns in terms of clinical performance and child acceptance.

Inclusion Criteria:

• Medically fit or with mild systemic illness (ASA I or II).
• Children who assent to take part in the study with a valid parental consent
• Children who have at least one first permanent molar requiring a full-coverage restoration (indications for placing a crown include: badly destructed/carious molars, or teeth affected by molar-incisor hypomineralisation (MIH))
• Maxillary or mandibular fully erupted first permanent molars, regardless of the stage of root development.
• A cooperative child that accepts dental treatment (Frankle Behaviour Rating Scale #3 or 4).
• Capable of attending all follow-up sessions.

Exclusion Criteria:

• Patients outside the required age range
• Parents/child not willing to participate.
• Medically compromised patients
• Partially erupted permanent first molars.
• Patients with severe malocclusion that prohibits the provision of crowns
• First permanent molars are not indicated for full coverage restorations.
• First permanent molars are indicated for extraction.
• Patients with bruxism or parafunctional habits.
• Uncooperative children (Frankle Behaviour Rating Scale #1 or 2)