Peg-shaped maxillary lateral incisors are most strongly associated with which other finding?

Correct answer: C. Impacted (palatally displaced) maxillary canines

• A. Impacted central incisors are usually caused by a local obstruction — supernumerary tooth, odontoma, or trauma to the primary predecessor.
• B. Impaction of mandibular second premolars relates to crowding and early loss of the second primary molar.
• C. CORRECT. A peg-shaped or congenitally absent maxillary lateral incisor is a well-established marker for PALATALLY DISPLACED MAXILLARY CANINES. The guidance theory explains why: the erupting canine normally uses the distal root surface of the lateral incisor as a guide, and when that root is short, malformed or missing, the canine loses its guide and deflects palatally. Palatal displacement is also part of a broader genetic pattern of dental anomalies that includes peg laterals, hypodontia, infraoccluded primary molars and small teeth.
• D. Third molar impaction is chiefly a matter of arch length and retromolar space, not lateral incisor form.

Note: The clinical consequence is a screening rule: in any child with a peg or absent lateral incisor, palpate for the canine bulge from around age 9–10. Absent bulge by age 10–11 warrants radiographic localisation, because interceptive extraction of the primary canine can redirect the permanent canine in a substantial proportion of cases.