Dentoalveolar development in subjects with normal occlusion. A longitudinal study between the ages of 5 and 31 years
Department of Orthodontics, The Sahlgrenska Academy, University of Gothenburg, Sweden
Address for correspondence Professor Birgit Thilander, Department of Orthodontics, The Sahlgrenska Academy, University of Gothenburg, Box 450, SE-405 30 Göteborg, Sweden E-mail: birgit.thilander{at}odontologi.gu.se
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The aim of the present study was to examine dentoalveolar development in subjects with an ideal (normal) occlusion. The material comprised 436 study casts of 189 male and 247 female subjects of Swedish origin between the ages of 5 and 31 years with no history of orthodontic treatment. Tooth width, and arch length, width, and depth, as well as palatal height were measured. The data were analysed with a Student's t-test.
The results verified that continuous changes of the dental arches occur from the primary until the adult period, with individual variations. This change could be interpreted as a biological migration of the dentition, resulting in anterior crowding especially in the mandible, even in subjects with congenitally missing third molars.
The occlusion should be regarded as a dynamic rather than a stable interrelationship between facial structures. This natural development has to be considered in orthodontic treatment planning as well as in assessment of stability following orthodontic treatment. A continuous increase of palatal height up to adulthood seems to be an effect of a slow continuous eruption of the teeth. This finding is also of significance in explaining the infraposition of implant-supported crowns.