Facemask(FM) is an orthopedic appliance with extraoral and intraoral anchoring units used in treatment of maxillary retrognathia. Aim of this study was to assess effects of tooth-supported FM application via fixed orthodontic appliances on craniofacial structures with finite element stress analysis.

A model was constructed on maxillary teeth with Roth brackets (0.018″slot), 0.018″x0.025″ stainless steel archwire, and crimpable hooks placed distal to upper lateral incisors. The scenario included application of FM with 350 g force, forming 30° angle with occlusal plane. Stress distributions and displacements on craniofacial bones, sutures, intraoral anchoring unit and maxillary teeth were evaluated.

High stress distributions were observed in anterior maxilla, pterygomaxillary region, zygomatic arch, and frontal process of zygomatic bone. Zygomaticotemporal, zygomaticofrontal, pterygomaxillary sutures and intraoral anchoring unit showed high stress distributions too. Stresses along maxillary teeth were not uniform, declaring increased stress distributions at the anterior region, but tended to decrease to posterior. Forward displacement was observed in all landmarks and counterclockwise rotation of maxilla and dentition were observed vertically. Narrowing in maxillary dental arch was observed.

Tooth-supported FM application over the brackets created stresses on craniofacial bones and sutures. Increased stress distribution were evident at the anterior maxillary region close to the force application points. Displacements were observed in all directions, drawing special attention to transversal narrowing and counterclockwise rotation of maxilla. In this respect, clinical attention should be made during FM application anchored from fixed braces, with either using rigid archwires or supporting mechanics with transpalatal arches.