Introduction and Research Problem:

The aim of this project is to evaluate and compare two full coronal restorations on primary posterior molars over a period of 3, 6 and 12 months in terms of restoration failure, marginal integrity, proximal contact, secondary caries, occlusion and gingival response. The restorations types are Stainless Steel Crowns (SSC) and NuSmile Zirconia Crowns (Nu/ZR).

Materials and Methods:

Children attending the King Abdulaziz University, Faculty of Dentistry (KAUFD) clinics who need restorations will be screened for inclusion criteria till 120 teeth are recruited (60 teeth for SSC restorations and 60 for Nu/ZR restorations). Split mouth technique will be used to ensure equalizing variables for both groups, each patient will have side restored with SSC and the opposite side will be restored with Nu/ZR crowns.

Randomization will be done using Statistical Package for the Social Sciences (SPSS) software version 20.0 (Armonk, New York; International Business Machines Corporation (IBM Corp) for each age group separately with a uniform random variable generation. A simple descriptive statistics will be used for analysis and a T-Tests with Wilcoxon Signed-Rank will be used. Level of significance will be set at (α = 0.05) and level of confidence at (95%).

Inclusion Criteria:

• Age group of 4-8 years
• Free of any systemic disease
• Cooperative patient
• At least two matched bilateral carious primary molars
• Minimal of two surfaces of caries in the targeted tooth
• Written consent obtained from the parent/guardian

Exclusion Criteria:

• Any subject that does not fall under the inclusion criteria were excluded.