298 - Congenital Unilateral Lower Lip Palsy and Its Impact on Smiling

Introduction: Congenital unilateral lower lip palsy (CULLP), an uncommon congenital anomaly of the depressor anguli oris, is found in 0.6% of newborns with left side predominance (80%). CULLP is characterized by unilateral lower lip depression during crying or smiling while the face remains symmetric at rest. Notably, it can mimic other forms of facial palsy in children.

Case Report: 7-year-old male presented to pediatric dentist for routine care. The pediatrician was monitoring an asymmetry in the lower lip that was becoming more noticeable when smiling. Facial symmetry was observed at rest, and a neurological assessment revealed lower left lip weakness with normal sensation. End-to-end occlusion of left lateral incisors and perioral dermatitis were observed. The child was referred to pediatric plastic surgery for treatment options.

Conclusion: Recognizing CULLP is important to differentiate it from other facial palsies that may affect oral function or be associated with systemic diseases and syndromes.

 

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