Maxillary Lateral Incisor Agenesis in Relation to Overall Tooth Size

Objectives: Agenesis of maxillary lateral incisors is a frequent finding in orthodontic patients. This study evaluates the relationship of agenesis of the maxillary lateral incisor(s) to overall tooth size of the remaining teeth which could potentially result in compromised restorative treatment after orthodontic therapy. 

Methods: Forty sets of dental casts (21 females, 19 males - mean age 15.9 years), with missing maxillary lateral incisors (22 unilateral, 18 bilateral), were compared to the same number of casts from a control group matched for ethnicity, age and gender. A digital caliper was used the measure mesio-distal width for all maxillary and mandibular teeth, except second and third molars. The independent t-test and Mann-Whitney test were used to analyze the data for tooth-width measurements, and the Shrout-Winer test was used to determine the measurement reliability of the investigator.

Results: Male subjects in the test group had significantly smaller maxillary posterior teeth than the control group, with differences ranging from 0.28-0.78mm. Females showed significantly smaller maxillary anterior teeth, with differences ranging from 0.22-0.42mm. When present, the contralateral maxillary lateral incisor was significantly smaller (1.27mm) than the control group in male and female groups.

Conclusions: Orthodontic patients with agenesis of one or both maxillary lateral incisors tend to exhibit smaller maxillary posterior teeth in males, and smaller mandibular anterior teeth in females. Also, a higher incidence of smaller contralateral lateral incisors was found for the test group when only one lateral incisor was missing.