Cranial base characteristics in anteroposterior malocclusions: A meta-analysis

Area of Science:

• Orthodontics and Dental Anthropology
• Craniofacial Morphology Research

Background:

• Sagittal discrepancies in occlusion, classified as Class I, II, or III, are common orthodontic concerns.
• Understanding the underlying skeletal morphology, particularly cranial base characteristics, is crucial for diagnosis and treatment planning.

Purpose of the Study:

• To systematically investigate and compare cranial base dimensions and angles in individuals with different types of malocclusions (Class I, II, and III).
• To provide a quantitative synthesis of existing evidence on cranial base morphology in relation to sagittal discrepancies.

Main Methods:

• A comprehensive electronic literature search was conducted across major databases (PubMed, Embase, Web of Science, Cochrane Library).
• A meta-analysis using fixed- or random-effect models was performed to calculate weighted mean differences and 95% confidence intervals for cranial base measurements.
• Included studies analyzed anterior, posterior, and total cranial base length, as well as cranial base angle.

Main Results:

• Class III malocclusion was associated with significantly reduced anterior and total cranial base length compared to Class I and Class II.
• Class II malocclusion demonstrated significantly greater anterior and total cranial base length compared to Class I.
• Cranial base angle was significantly smaller in Class III and Class II malocclusions compared to Class I, and also smaller in Class III compared to Class II.

Conclusions:

• Significant differences in cranial base morphology exist among different sagittal malocclusion classes.
• Class III malocclusions are characterized by smaller cranial base lengths and angles, while Class II malocclusions present with larger cranial base lengths compared to Class I.