The human mouth is divided into four dental quadrants: upper right, upper left, lower left, and lower right. Each quadrant in the primary dentition contains five teeth—two incisors (central and lateral), one canine (cuspid), and two molars—totaling 20 baby teeth. Notably, primary dentition does not include premolars. These teeth begin erupting around 6 months of age, following a predictable sequence: central incisors, lateral incisors, first molars, canines, and finally second molars, usually co