Occlusal Morphology of Mandibular First Primary Molars in a Sample of Egyptian Children: A Cross-Sectional Study

Background: The occlusal morphology of primary teeth plays a crucial role in dental development, masticatory function, and long-term occlusal stability. Despite extensive documentation of morphological variations across populations, limited data exist on Egyptian children. This study aimed to investigate the occlusal morphological features of mandibular first primary molars in a sample of Egyptian children, addressing a critical gap in anthropological and clinical dental research. Methods: A cross-sectional study was conducted on 150 dental casts obtained from Egyptian children visiting the clinics of …… university. Standardized alginate impressions were poured in Type III dental stone and evaluated by three calibrated examiners. Key occlusal features: cusp number, groove configuration (Y-shaped or H-shaped), and outline morphology (oval, rhomboidal, or heart-shaped) were assessed. Statistical analysis was performed using SPSS 20®, with frequency distributions and chi-square tests for comparisons. Results: The most prevalent morphology was a 3-cusp arrangement with Y-shaped grooves (40.0%), followed by 4-cusps with H-shaped grooves (33.3%). Oval occlusal outlines predominated (50.0%), with rhomboidal (33.3%) and heart-shaped (16.7%) forms being less common. Significant differences were observed between occlusal outline shapes (p < 0.0001). The findings align partially with global trends but reveal distinct population-specific patterns, particularly the high prevalence of Y-shaped grooves and oval outlines. Conclusion: This study provides the first comprehensive analysis of mandibular first primary molar morphology in a sample of Egyptian children, highlighting unique traits with implications for clinical dentistry and anthropological research. The results underscore the importance of population-specific dental standards .