The purpose of this study is to evaluate and compare the clinical and radiographic performance of zirconia and composite strip crowns bonded on primary incisors

Zirconia and composite strip crowns will be placed on at least two primary incisor teeth, in a split mouth design. A caries-free primary incisor tooth will be used as control. 100 patients will be included in the study. The teeth will be randomized into two groups according to the crown type.

Group 1: Zirconia crown 2: Composite Strip Crown 3: Control tooth. Plaque index, gingival index, crown retention, presence of restoration failure, gingival margin extension, color match of the crowns and pulpal health of the teeth will be clinically evaluated at baseline and 1., 6., 12., 18., 24. months. The restorations will be evaluated radiographically at 6., 12. and 18. months. Intra-oral photos will be taken directly after treatment and at control appointments.

The data will be analysed statistically using Fisher's Exact Test and pearson's chi-square test; and Log-rank and the Kaplan-Meier will be used to estimate survival percentages.

Inclusion Criteria:

• Patients and parent of the patients who accept to participate and sign the informed consent
• Patients who have at least two primary maxillary incisor with caries that require crown restoration
• Teeth that have healthy lamina dura and periodontal ligament
• Teeth with no mobility and enough root length
• Patients that have good cooperation to the procedure

Exclusion Criteria:

• Patients and parent of the patients who don't accept to participate and sign the informed consent
• Teeth that are previously restored
• Patients who are uncooperative
• Teeth that doesn't have opposing primary incisors
• Patients who have bruxism or deep-bite
• Teeth that are close to be erupted
• Teeth that have vital or non-vital pulp therapy