Different full-coverage crown materials are widely used in pediatric dentistry for the restoration of primary teeth with extensive substance loss. Since these restorations remain in close contact with gingival tissues for prolonged periods, they may influence periodontal health depending on their surface characteristics, marginal adaptation, and biological properties. The aim of this study was to evaluate the effects of stainless steel crowns (SSC), prefabricated zirconia crowns (PZC), and fiber-glass crowns (FGC) on periodontal health in children using both clinical periodontal parameters and gingival crevicular fluid (GCF) biomarkers, including IL-1β and MMP-8, within a split-mouth study design.