Frequency of Congenitally Missing Permanent Teeth in Japanese Children

Abstract

Congenitally missing permanent teeth (CMPT) is one of the most frequent anomalies in dentistry. CMPT affects not only the occlusal relationships within the maxilla and mandible, but also the total occlusion. In addition CMPT can lead to future skeletal and facial problems. The purpose of this study was to estimate the nation-wide frequency of (CMPT) in Japanese children. Prior to beginning this epidemiological study, the authors obtained permission for the investigation from the ethics committee of Kagoshima University Graduate School of Medical and Dental Sciences (June 25^th, 2007).Seven pediatric clinics at dental colleges or universities and several private pediatric clinics participated in this study. The sample consisted of 15,544 pediatric dental patients (7,502 males and 7,502 females). Data were collected from longitudinal dental X-rays, orthopantomograms, and some dental models to determine CMPT (excluding 3^rd molars) within 6 months. All patients were judged to be over 7 years of age if they had all their permanent teeth in the dental films. In cases where it was difficult to judge the kind of tooth or its location, the committee members from all 7 colleges/universities reached a consensus on the number of missing teeth and their locations on a case by case basis.A total of 1,568 subjects (10.09%) were diagnosed with CMPT. Of these, 685 were males (9.13%),and 883 were females (10.98%). Differences between the maxilla and the mandible were seen in 4.37% of males and 7.58% of females. Differences between the right and left sides were seen in 0.11% of males and 0.14% of females. The most common missing tooth was the lower second premolar ; missing in 2.96% of adolescents, 2.64% of males (1.32% both sides) and 3.31% of females (1.72% on the right side and 1.59% on the left side). In descending order the next most common missing teeth were the mandibular lateral incisors, the maxillary second premolars, and the upper lateral incisors.