The study was planned to evaluate and compare the clinical success of prefabricated stainless steel crowns and zirconia crowns used in the primary molars.

The study will be carried out in healthy children aged 6-9 years with caries on more than one surface of the primary molars.

In this study, zirconia crowns will be compared with prefabricated stainless steel crowns in a randomized controlled manner. The study will be conducted in split-mouth to eliminate the effect of potential confounders. The obtained data will be analyzed using appropriate statistical methods.

Inclusion Criteria:

• Healthy children aged 6-9 years with caries on primary molars
• Children without systemic disease or developmental dental anomalies that may affect caries susceptibility.
• Children whose cooperation is 'positive' or 'absolutely positive' according to the Frankl behavioral scale (Frankl et al., 1962).
• Those with deep dentin caries that do not extend to the pulp in the teeth to be treated
• The molars will be treated with a crown indication.
• Presence of symmetry of the primary molar to be treated in the opposite arch.
• The molar to be treated is in occlusion with the antagonist.
• Presence of caries on at least two surfaces of the molars to be treated.
• Absence of spontaneous pain, abscess, mobility, interradicular lesion in the tooth to be treated
• Patients whose parents and themselves agree to participate in the treatment

Exclusion Criteria:

• Children whose treatment cannot be continued on the dental chair due to cooperation
• Molars that will soon be exfoliated, 1/2 of the root has been resorbed
• The presence of bruxism
• The presence of erosion or attrition-related wear on the opposing molar
• The patient does not come to the control appointment or does not want to continue to the research
• Have allergy to local anesthetic, nickel or chromium
• Complications during treatment.