Presence of third molars in orthodontic patients from northern Greece

Third molars (M3s) can be present or absent in the oral cavity. Their presence is characterized by the considerable variability in eruption timing, the level of eruption, and their angular positions. In addition, as they are the last teeth to develop, they are most frequently impacted. Many complications, such as caries and distal root resorption of the adjacent second molar teeth or late crowding of the anterior teeth, have been attributed to the presence of M3s, which may compromise the results of orthodontic treatment. The development stage of the M3s has been explored by several authors in different populations. According to Massler et al1 M3 calcification starts at 7–10 years of age, calcification of the crown is completed at 12–16 years of age, and eruption begins at 17–21 years of age. Garn et al2 reported that the age limit for M3 genesis is 13 years, while Richardson3 suggested that M3 genesis may occur up to the age of 16 years old. In Japanese and Israeli populations,4,5 it is reported that calcification of M3s begins at approximately 8 years and that the average age for completion of the M3 crowns is 12 years, while in Spanish children the onset of mandibular M3 formation was observed at very variable ages, ranging from 5.86 to 14.66 years.6 To date, the causes of agenesis of one or more M3s are essentially unknown. Several mechanisms have been suggested, such as physical disruption of the dental lamina and the absence of an epithelial signal to the ectomesenchyme,7 the failure of a tooth bud to reach a critical size,8 or more proximately, to receive the signaling to continue development.9 Space limitation and crowding are also involved in the agenesis of M3s10 as well as racial variations in facial growth, jaw size, and tooth size.11 The aim of this descriptive study was to investigate the presence of M3s in a group of orthodontic patients with permanent dentition from northern Greece. The presence of M3s in each jaw, according to sex, and their relationships were also investigated. It was considered worthwhile to explore the status of M3s in this population and to compare the obtained data with the results of previous studies conducted on American, European, and Asian patients.