Background and purpose: The prevalence of maxillary missing lateral incisor (MMLI) is 1-2% which is responsible for 20% of all missing teeth. Increased knowledge about causes and clinical manifestations of cases with this situation can be helpful for diagnosis and treatment planning. The aim of the present study was to determine dental and skeletal features of patients with missing maxillary lateral incisors.

Materials and methods: The material consisted of pre-treatment dental casts and cephalograms of 26 patients with unilateral or bilateral MMLI. The following parameters were measured on dental casts: the maxillary and mandibular intercanine width (ICW) and intermolar width (IMW), overjet, overbite, missing or anomalous of other teeth. Parameters that were measured on cephalogram included: SNA, SNB and ANB angle and Wits. The parameters were finally compared to a control group with normal occlusion using paired t-test.

Results: Eight subjects with MMLI had bilateral missing and in 18 subjects with unilateral missing, 66.67% (n=12) had lateral missing on the right side. MMLI was associated with other anomalies or congenital tooth absence in 12 subjects. The overject was significantly lower compared to that in the control group (P=0.05) and upper and lower ICW were smaller. Both ANB angle and Wits significantly decreased in this group (P=0.05). 

Conclusion: Absence of maxillary lateral incisor was highly correlated with other tooth anomalies. Most of patients with this situation had skeletal and dental Class III tendency.