A comparison of 2- and 3-dimensional mandibular superimposition techniques against Björk's structural superimposition...

Area of Science:

• Orthodontics and Dental Anthropology
• Craniofacial Development and Growth

Background:

• Assessing mandibular growth rotation is crucial for understanding facial development.
• Various two-dimensional (2D) and three-dimensional (3D) superimposition methods exist, but their accuracy varies.

Purpose of the Study:

• To compare the accuracy of different 2D and 3D superimposition methods for assessing mandibular growth rotation relative to the cranial base.
• To evaluate method agreement across different vertical facial patterns and time intervals.

Main Methods:

• Cone-beam computed tomography (CBCT) scans from 70 growing patients were analyzed.
• Three superimposition methods (2D-M1, 3D-M1, 3D-M2) were compared against Björk's structural method.
• Statistical analyses included Lin's concordance correlation coefficient, Bland-Altman limits of agreement, and the Bradley-Blackwood test.

Main Results:

• The 3D-M2 method demonstrated high concordance (0.965) with Björk's method, superior to 2D-M1 (0.924) and 3D-M1 (0.695).
• Bland-Altman analysis and the Bradley-Blackwood test indicated superior agreement and reliability for the 3D-M2 method.
• The 3D-M2 method's accuracy was consistent across all vertical facial types and time intervals.

Conclusions:

• The 2D-M1 and 3D-M1 methods are not recommended for CBCT analyses with time intervals exceeding 3 years.
• The 3D-M2 method provides a reliable and accurate assessment of mandibular growth rotation, comparable to established structural methods.
• This validated 3D method is suitable for diverse patient populations and longitudinal studies in orthodontics.