Three-dimensional finite element study of mandibular first molar distalization with clear aligner

Area of Science:

• Orthodontics
• Biomaterials Engineering
• Dental Mechanics

Background:

• Finite element analysis (FEA) is crucial for simulating complex biomechanical interactions in orthodontics.
• Understanding tooth movement with invisible appliances and micro-implant anchorage is essential for effective treatment planning.

Purpose of the Study:

• To construct a finite element model of the mandibular first molar with an invisible appliance.
• To explore dentition movement characteristics using micro-implant anchorage and varying initial positions of the mandibular first molar.

Main Methods:

• Cone beam computed tomography (CBCT) data used to create models of the mandible, teeth, periodontal membrane, and appliance.
• Two groups: non-anchorage and micro-implant assisted.
• Four working conditions based on initial molar-premolar distance (0-3 mm).

Main Results:

• Non-anchorage group: first molar moved distally, other teeth showed reverse movement.
• Micro-implant group: predominantly distal dentition movement, anterior teeth lingual movement; largest distal first molar displacement in condition 4 (3 mm gap).
• Increasing initial distal molar position enhanced distal molar and premolar movement, and anterior labial movement, while decreasing mesial second molar movement.

Conclusions:

• Micro-implants effectively preserve anterior anchorage and promote molar distalization.
• Micro-implants prevent undesirable mesial movement of the second molar.
• The initial position of the mandibular first molar significantly impacts the degree of distalization and overall tooth movement.