RESUMO
Missing and supernumerary teeth are considered as dental developmental anomalies. These anomalies may lead to problems and complications such as dental asymmetry, poor esthetics, midline shift, dental crowding, malocclusions, caries, diastema, ectopic eruption, impactions, delayed eruption, external root resorption as well as loss of adjacent tooth's vitality in some cases. The aim of this study was to investigate the prevalence of missing and supernumerary teeth in 3 to 5 years old kindergarten children of Tehran in 2005. This cross-sectional study was conducted by oral examination of 1000 children. Kindergartens were randomly selected in three major areas of Tehran province, namely Rey, Tehran-city and Shemiranat regions. Oral examination was carried out by counting the teeth under adequate lighting. The prevalence of supernumerary and missing teeth in this study was 0.3% and all the anomalies were observed in boys. All cases of supernumerary teeth were in maxilla. From the three cases with missing teeth, two cases were in the maxilla [83%] and one case in the mandible. The anomalies observed in two samples occurred unilaterally in the lateral incisors [67%].Since missing and supernumerary primary teeth may lead to problems in the permanent dentition, early diagnosis and continuous monitoring of successors seem to be necessary to avoid further problems and therefore complicated treatments