Unilateral Angle II in functional lateralities

Area of Science:

• Orthodontics and Dental Anthropology
• Neuroscience and Developmental Biology

Background:

• Unilateral Angle II malocclusion is a common dental issue.
• Functional lateralization (eye, hand, foot dominance) may influence craniofacial development and occlusion.
• Understanding these relationships is crucial for diagnosing and treating malocclusions.

Purpose of the Study:

• To investigate the prevalence of unilateral Angle II malocclusion in children based on their functional sidedness (true right-sided vs. non-right-sided).
• To compare the symmetry of occlusal relationships between functionally right-sided and non-right-sided children.
• To explore the potential link between lateralized functions and the development of malocclusion.

Main Methods:

• A cross-sectional study of 1423 American children (mean age 8.5 years).
• Dental casts were used to assess sagittal occlusal relationships (Angle I, II right, II left).
• Hand, foot, and eye preferences were recorded at age 4.

Main Results:

• Unilateral Angle II right malocclusion occurred in 9% and Angle II left in 6.5% of the general population.
• In moderate non-right-sided children, Angle II right prevalence was 17% (vs. 3% for Angle II left).
• True right-sided children exhibited greater occlusal symmetry (85% bilateral Angle I or II) compared to non-right-sided children (80%), with statistically significant differences (P < 0.02).

Conclusions:

• Functional sidedness is associated with occlusal symmetry and malocclusion prevalence.
• Asymmetries in neurocranium, cranial base, and masticatory apparatus likely play a role.
• Normal symmetric occlusion may involve compensatory growth, challenging early orthodontic intervention in suspected unilateral Angle II cases.