Which congenital tooth anomaly is MOST commonly missing (congenitally absent) in patients with ectodermal dysplasia or X-linked Duchenne syndrome?

Correct answer: B. Lateral incisors (#7 and #10) — most commonly missing permanent teeth overall

• A. Central incisors (#8 and #9) are very rarely congenitally missing — when they are, it suggests a significant syndrome.
• B. Correct. LATERAL INCISORS (maxillary) are the most commonly congenitally missing permanent teeth in the general population. In conditions associated with hypodontia (Duchenne syndrome, ectodermal dysplasia with X-linked inheritance patterns), lateral incisors (#7 and #10) are most frequently absent. Third molars are excluded from hypodontia counts.
• C. Second premolars (#20 and #29) are the second most commonly missing permanent teeth — but lateral incisors are first.
• D. Canines (#6 and #11) are rarely congenitally absent — they have the highest eruption priority.