engleski

Longitudinal changes of dental arch shape during adolescence and occurrence of late mandibular incisor crowding

Introduction: Occurrence of late crowding in the mandibular incisor region is a common request for orthodontic treatment. Various theories about its aetiology have been proposed throughout the years. Dental arch width and length change during lifetime, due to facial growth and development of dentition and could be one of the factors contributing to late mandibular crowding. Objective: To assess the relation between late mandibular crowding and changes in dental arch shape during adolescence. Materials and Methods: The sample included 71(48% female) orthodontically untreated subjects, recalled for check-up every three years, from the Nittedal growth study, Norway. Patients` plaster casts at the age of 12, 15, 18 and 21 were analysed. Measurements included anterior arch length, anterior width, posterior width and the Little index. The ratio between anterior arch length and anterior width was measured to evaluate the dental arch shape. Results: The increase in Little index (p<0.001) and change in dental arch shape (p<0.001) was observed during development in adolescence. The dental arch became more squared-shaped with age. Changes were mostly due to the significant decrease in anterior arch length (p<0.001). The anterior arch width did not demonstrate significant changes over time. No differences in gender were observed. The amount of mandibular incisor crowding did not show a linear relation with changes in dental arch shape. Conclusion: Mandibular incisor crowding increases and changes in dental arch shape do occur during adolescence, however, no linear relation is observed among these two phenomenons.

late crowding, dental arch shape

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