The peg-shaped lateral incisor is one that has an incisal mesiodistal width of the tooth crown shorter than the cervical width. This can lead to aesthetic, orthodontic and periodontal problems for the patient.  The aim of this review was to assess the prevalence in relation to race, sex, population type and continent of origin.

The PubMed, Embase, Google Scholar, Cochrane Central Register of Controlled Trials, metaRegister of Controlled Trials, and OpenGrey databases were searched with no restrictions. Studies reporting the occurrence rate of peg-laterals were included. Screening and quality assessment of studies was conducted in duplicate. The overall pooled prevalence estimate was calculated with a random-effects model. An estimated risk ratio was used for sex comparison. The studies were divided into 4 main groups: Black, White, Mongoloid, and Indian.

• 30 articles were included from 17 countries describing 87,172 patients.
• The pooled overall prevalence of peg-laterals in this analysis was 1.8% (95% CI, 1.5-2.1)
• The occurrence rate of peg-laterals among Mongoloid subjects (3.1%; 95% CI, 1.9-4.3) was significantly higher than that of black (1.5%; 95% CI, 1.1-1.9) and white (1.3%; 95% CI, 1.0-1.6)
• The prevalence values for female subjects were significantly higher than for male subjects (risk ratio, 1.35; 95% CI, 1.13-1.61).
• The prevalence of unilateral peg-laterals (0.8%; 95% CI, 0.6-1.0) was found to be the same as for bilateral peg-laterals (0.8%; 95% CI, 0.5-1.1)
• Among those with unilateral peg-laterals, left-side ones (0.4%; 95% CI, 0.2-0.6) were twice as common as right-side ones (0.2%; 95% CI, 0.1-0.3).

The authors concluded

The prevalence of peg-shaped maxillary permanent lateral incisors varies by race, population type, and sex. The prevalence rates were higher among Mongoloid people, orthodontic patients, and women. Although the prevalence of unilateral and bilateral lateral incisors was the same, the left side was twice as common as the right side. Subjects with unilateral peg-shaped maxillary permanent lateral incisors might have a 55% chance of having lateral incisor hypodontia on the contralateral side.

Links

Hua F, He H, Ngan P, Bouzid W. Prevalence of peg-shaped maxillary permanent lateral incisors: A meta-analysis. Am J Orthod Dentofacial Orthop. 2013 Jul;144(1):97-109. doi: 10.1016/j.ajodo.2013.02.025. PubMed PMID: 23810051.