A patient presents with an abnormally large mandibular tooth that appears to have two crowns joined at the base. On counting the teeth, the patient has a NORMAL total tooth count. What is the diagnosis?

Correct answer: A. Gemination

• A. CORRECT. GEMINATION is an attempt by ONE tooth germ to divide into two, resulting in a large tooth with double or bifid crown and a single root, but the tooth count remains NORMAL because it is one tooth germ. FUSION involves the union of TWO separate tooth germs, resulting in a reduced tooth count (one fewer tooth than expected). If count is normal → GEMINATION.
• B. Macrodontia is simply an abnormally large tooth — it does not have a bifid or double crown appearance.
• C. Taurodontism is characterized by an enlarged pulp chamber extending into the roots — the crown size may appear normal. It is not associated with a bifid crown.
• D. Fusion reduces the total tooth count by one (two tooth germs unite to form one tooth). If the count is normal, fusion is ruled out.