Changes in dentofacial structures in untreated Class II division 1 and normal subjects: a longitudinal study

Area of Science:

• Orthodontics
• Craniofacial Development
• Dentofacial Anthropology

Background:

• Class II division 1 malocclusion is characterized by specific dentofacial discrepancies.
• Understanding longitudinal changes in untreated individuals is crucial for establishing normative growth patterns.

Purpose of the Study:

• To longitudinally compare dentofacial structure changes from deciduous to permanent dentition in untreated Class II division 1 and normal subjects.
• To identify specific developmental differences between these groups over time.

Main Methods:

• Longitudinal cephalometric analysis of 65 untreated subjects.
• Data collected at three developmental stages: deciduous, mixed, and permanent dentition.
• Comparison of cross-sectional and longitudinal growth trends.

Main Results:

• No significant longitudinal differences in growth trends between groups, except for upper lip protrusion.
• Cross-sectionally, mandibular length differed in earlier stages but normalized later, suggesting catch-up growth.
• Significant differences in total change included greater maxillary/mandibular lengths in normal subjects and increased convexity in Class II subjects.

Conclusions:

• Longitudinal dentofacial growth patterns are largely similar between untreated Class II division 1 and normal individuals.
• Class II division 1 subjects exhibit increased skeletal and soft tissue convexity by the permanent dentition stage.
• Upper lip protrusion is a key distinguishing feature in untreated Class II division 1 individuals.