Two different designs of mini-screw assisted maxillary expanders, using FEM to analyse stress distribution in craniofacial structures and anchor teeth.

Objective: The objective of this study was to analyse the displacement, strain, and stress distribution of various craniofacial structures after applying maxillary expansion with two different bone-borne Haas-inspired miniscrew-assisted maxillary expander (BB HIMAME) and bone-tooth-borne miniscrew-assisted rapid palatal expander (BTB MARPE) using three-dimensional finite element analysis (3D FEA).

Material And Methods: two expanders including bone-anchored maxillary expander and bone tooth-borne were designed to simulate expansion in a 3D FEA. Expanders were activated transversely for 0.2mm. The stress distribution and displacement of various craniofacial structures and anchor teeth were calculated.

Results: The finding showed that the amount of stress in all sutures was greater in BB than BTB expander. The greatest stress was induced in the fronto-maxillary suture in the BB expander, which was 4.45MPa. While it was 0.7MPa in BTB. Anchor tooth showed tipping movement in BTB expander, although the crown and apex of the anchor tooth moved in the same direction with BB device.

Conclusions: It is recommended that the BB expander is used when bodily movement of anchor tooth is needed. BTB may serve as an effective modality for cases with low-quality bone conditions. BTB appliance creates some extent of tipping on anchor teeth.