固定矯正治療におけるアンカースクリューの有無によるアンカース失調の比較評価：クラスI顎骨抜歯デザインにおける有限要素解析

The study used finite element analysis (FEA) to assess and quantify anchorage loss during simultaneous retraction and intrusion with or without anterior mini-implants under different forces.

CBCT scans of a skeletal Class I patient were used. Mimics Research 18.0 was used to construct a maxilla 3D model from scans. FEA was done with ANSYS 2024 R2 employing a model with bilateral mini-screws and a control model without mini-screws. Each model received a 100g retraction force and additionally vertical intrusive forces 90 g, 120 g, and 150 g in model 2. Both models were limited to the superior maxilla and had appliance component glued connections.

FEA indicated that simultaneous intrusion and retraction enhanced maxillary first molar anterior displacement. The least displacement (6.24E-06 mm) occurred in model without mini-implants, while maximum displacement (6.86E-06 mm) in model with bilateral mini-implants with highest intrusive force.

This study showed that conventional retraction without intrusive forces minimizes anchorage loss. With increasing force magnitude of intrusion, anterior molar displacement also increases.