Tricortical versus bicortical anchorage in a double-screw tandem skeletal expander and a single-screw maxillary anchorage rapid palatal expander: A finite element analysis.

Objective: This study aims to employ finite element method (FEM) analysis to compare the differences between bicortical and tricortical anchorage of the posterior miniscrews in a single-screw miniscrew-assisted rapid palatal expansion (MARPE) and a double-screw tandem skeletal expander (TSE) under open and closed suture conditions. Methods: A cone beam computed tomography of the human skull of a 21.5-year-old female was utilized as a model for creating a FEM analysis. Simulations involved the insertion of four palatal miniscrews: two anterior ones with bicortical anchorage and two posterior ones (one with bicortical and another with tricortical anchorage), under open and closed suture conditions in a single-screw MARPE and double-screw TSE, resulting in a total of eight different simulation configurations. Evaluation parameters include total deformation (mm), Von Mises stress (MPa), and strain for each miniscrew body. Results: Tricortical anchorage of the posterior miniscrews provides greater anchorage, higher stress, and deformation on the anterior miniscrews in single-screw MARPE. Tricortical anchorage combined with a double-screw TSE promotes a more even distribution of force and stress on miniscrews under open suture conditions, leading to a parallel midpalatal suture opening along its entire length and height. Conclusions: FEM analysis revealed favorable midpalatal suture opening with equal force distribution and less stress when posterior tricortical anchorage in conjunction with double-screw TSE is applied.

Comparison of the accuracy of digital face scans obtained by two different scanners.

OBJECTIVES: To compare the degree of accuracy of the Face Hunter facial scanner and the Dental Pro application for facial scanning, with respect to both manual measurements and each other. MATERIALS AND METHODS: Twenty-five patients were measured manually and scanned using each device. Six reference markers were placed on each subject's face at the cephalometric points Tr, Na', Prn, Pog', and L-R Zyg. Digital measurement software was used to calculate the distances between the cephalometric reference points on each of the scans. Geomagic X Control was used to superimpose the scans, automatically determining the best-fit alignment and calculating the percentage of overlapping surfaces within the tolerance ranges. RESULTS: Individual comparisons of the four distances measured anthropometrically and on the scans yielded an intraclass correlation coefficient index greater than .9. The t-test for matched samples yielded a P value below the significance threshold. Right and left cheeks reached around 60% of the surface, with a margin of error between 0.5 mm and -0.5 mm. The forehead was the only area in which most of the surface fell within the poorly reproducible range, presenting values out of tolerance of more than 20%. CONCLUSIONS: Three-dimensional scans of the facial surface provide an excellent analytical tool for clinical evaluation; it does not appear that one or the other of the measuring tools is systematically more accurate, and the cheeks are the area with the highest average percentage of surface in the highly reproducible range.

Early class III treatment with hybrid rapid palatal expander combined with facemask.

BACKGROUND: Class III patients are characterized by a deficiency of the maxilla and/or a prognathism of the mandible and require early treatment. DIAGNOSIS: This case report describes the treatment of a 5-year-old patient with a skeletal class III relationship, a significant mandibular symphysis deviation towards the right side and a different height of the mandibular angles. MANAGEMENT AND OUTCOME: The patient was treated with rapid maxillary expander combined with miniscrew, facemask and aligners. A functional and aesthetic occlusion in an improved facial profile was established at the end of the orthodontic treatment. Pre-treatment, post-treatment and one year retention records for the patient are presented. DISCUSSION: Class III patients require early treatment in order to optimize the traditional expander effects; subsequently hybrid anchorage allowed to maximize skeletal advancement. In addition, loss of space for the erupting teeth and dento-alveolar tipping were avoided. The good results of the phase I treatment and of the active retainer meant that a complex case would become relatively simple at the phase II treatment.