Comparative study between the SFS and LFS rotation as a possible morphogenic mechanism

Area of Science:

• Dentistry
• Orthodontics
• Craniofacial Biology

Background:

• Facial morphology varies significantly, with distinct patterns observed in individuals with reduced or increased lower facial height.
• The long face syndrome (LFS) and short face syndrome (SFS) represent extremes of facial skeletal patterns.
• Understanding the underlying skeletal dynamics is essential for accurate diagnosis and treatment planning.

Purpose of the Study:

• To analyze cephalometric differences between individuals with reduced and increased lower facial height.
• To investigate potential subtypes within the long face syndrome.
• To explore the role of mandibular rotation in facial skeletal patterns.

Main Methods:

• Cephalometric analysis of adult Caucasians with reduced (LFS) and increased (SFS) lower facial height.
• Comparison of linear and angular measurements between the two groups.
• Subtyping of the LFS group based on specific cephalometric parameters.

Main Results:

• The LFS group exhibited distinct subtypes: Subtype I (long ramus, increased angles) and Subtype II (short ramus, backward/downward mandibular rotation).
• Both LFS and SFS patterns can be explained by clockwise or counterclockwise mandibular rotation, respectively, in conjunction with the hyoid, tongue, pharynx, and cervical spine.
• The need to maintain upper airway patency may influence mandibular rotation in LFS.

Conclusions:

• The long face syndrome presents with at least two distinct cephalometric subtypes.
• Mandibular rotation, influenced by surrounding structures, plays a significant role in determining facial skeletal patterns.
• These findings provide insights into the complex etiology of facial growth variations.