AMERICAN JOURNAL OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS, cilt.1, ss.1-15, 2022 (SCI-Expanded)
•The minimum stress for the craniofacial
structures was in the alveolar 2 miniscrew assisted model.
•For
the alveolar 2 miniscrew assisted model, the largest displacement was at the
anterior maxilla.
•For
the 4 miniscrew supported model, the greatest displacement occurs in the
posterior maxilla.
This study aimed to compare the effects of 3 different bone-borne type
expansion appliances used in the surgically-assisted rapid palatal expansion
(SARPE) by finite element analysis.
Three different miniscrew-supported palatal expansion appliances were
modeled. Median and lateral osteotomies were performed without pterygomaxillary
suture separation. Model I consisted of a palatal expander with 2 miniscrews
placed 4 mm far from the midpalatal suture. In model II, 2 miniscrews were
located at the alveolar ridge between the first molar and the second premolar.
In model III, 4 miniscrews were placed as a combination of the first and second
models. Stress distributions and amount of displacements were evaluated with
Ansys software (version 19.2; Ansys, Canonsburg, Pa) for 5-mm expansion in a
symmetrical finite element analysis model to reflect the clinical situation.
SARPE simulation using miniscrew-assisted maxillary expanders for all
models showed a rotation and tipping of the maxilla. The largest displacement
was found for the anterior part of the palate in model II and the posterior
part in model III. Although a wedge-shaped expansion pattern was observed in
all models, this form was more prominent in model II. The highest stress value
(0.91 MPa) was measured in model I, and the lowest value (0.004 MPa) was
measured in model II for the anterior nasal spine region. The highest stress
value (0.51 MPa) was measured in model III, and the lowest value (0.12 MPa) was
measured in model II for the posterior nasal spine region. The lowest stress
values were measured in model II for all the craniofacial and maxillofacial
structures.
Among the models, the lowest stress distribution conditions for
craniofacial and maxillofacial structures were found in model II. The largest
displacement was found at the incisors and anterior part of the maxilla for
model II. The greatest displacement was found at the posterior region for model
III.