Peg-Shaped Lateral Incisors
The most common anomaly in tooth shape in the anterior of the secondary dentition is the peg-shaped (or cone-shaped) lateral incisor, occurring in 1-2% of the population. The tooth is generally conical in shape, broadest cervically, and tapers toward the incisal to a blunt point. Several studies of the identical twins seem to indicate that missing and peg-shaped lateral incisor teeth may be varied expressions of the same generic trait. A most unusual occurrence is that of peg-shaped maxillary central incisor. Peg-shaped teeth develop from one facial lobe (instead of the three facial lobes normally present on anterior teeth).
Woelfel & Scheid. Dental Anatomy: Its Relevance to Dentistry. 6th Ed. 2002.page 331