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Individual variation in tooth-size/ arch-length changes from the primary to permanent dentitions
Samir E Bishara1, Jane R Jakobsen
1Orthodontic Department, College of Dentistry, University of Iowa, Iowa City 52242, USA. sbishara@msn.com
World Journal of Orthodontics
|June 20, 2006
Summary
Dental arch length and tooth size relationships show significant individual variation between primary and permanent dentitions. Approximately half of individuals change their relative tooth-size/arch-length ranking from childhood to adolescence.
Area of Science:
- Orthodontics and Dental Development
- Craniofacial Growth and Morphology
Background:
- Understanding tooth-size/arch-length relationships is crucial for predicting and managing orthodontic treatment needs.
- Longitudinal data on the stability of these relationships from primary to permanent dentition are essential for early diagnosis.
Purpose of the Study:
- To assess individual variations in maxillary and mandibular tooth-size/arch-length relationships.
- To compare these relationships between the primary dentition (mean age 4.0 years) and the permanent dentition (mean age 13.3 years).
Main Methods:
- Longitudinal study of 59 subjects (32 males, 27 females) with clinically acceptable occlusions.
- Measurement of mesiodistal tooth diameters and arch length parameters in both primary and permanent dentitions.
- Analysis of 60 dental parameters to evaluate changes in tooth-size/arch-length relationships.
Main Results:
- Nearly half of the subjects (49%) maintained their relative tooth-size/arch-length ranking between dentitions.
- A slightly higher proportion (51%) experienced a change, becoming more or less favorable in the permanent dentition.
- The probability of maintaining the same ranking was similar for the maxillary (49%) and mandibular (51%) arches.
Conclusions:
- Individual variability in tooth-size/arch-length relationships is significant, with about half of children experiencing changes.
- Subjects with less favorable primary dentition relationships had a 50% chance of improvement in the permanent dentition.
- Findings highlight the dynamic nature of dental arch development and have clinical implications for orthodontic assessment.
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