A reliable method for evaluating upper molar distalization: Superimposition of three-dimensional digital models

Abstract

ObjectiveThe aim of this study was to evaluate the reliability of measurements obtained after the superimposition of three-dimensional (3D) digital models by comparing them with those obtained from lateral cephalometric radiographs and photocopies of plaster models for the evaluation of upper molar distalization.MethodsData were collected from plaster models and lateral cephalometric radiographs of 20 Class II patients whose maxillary first molars were distalized with an intraoral distalizer. The posterior movements of the maxillary first molars were evaluated using lateral cephalometric radiographs (group CP), photocopies of plaster models (group PH), and digitized 3D models (group TD). Additionally, distalization and expansion of the other teeth and the degrees of molar rotation were measured in group PH and group TD and compared between the two groups.ResultsNo significant difference was observed regarding the amount of molar distalization among the three groups. A comparison of the aforementioned parameters between group PH and group TD did not reveal any significant difference.Conclusions3D digital models are reliable to assess the results of upper molar distalization and can be considered a valid alternative to conventional measurement methods.

Three-dimensional analysis of tooth movements after palatal miniscrew-supported molar distalization

“…25 The conventional method to measure the amount of movement of the molars and incisors from distalization is to use lateral cephalometric radiographies and dental cast photocopies. 26 Cephalometric radiographs involve radiation and may cause errors in landmark identification because of superimpositions of symmetrical anatomic structures. 27 Three-dimensional evaluations cannot be performed alone in either method; therefore, these 2 methods should be used in combination.…”

“…It is possible to make a reliable and an accurate 3D evaluation of tooth movements with digital models alone. 26 It is reported that pretreatment and posttreatment digital models can be reliably aligned without the need for a reference plane using reverse engineering software and the best-fit mathematical superimposition method. 17 This method uses the iterative closest point algorithm and needs stable regions on different models for superimposition.…”

“…It was reported that using digital models to evaluate dental changes after distalization treatment is reliable and has minor measurement differences when compared with conventional superimposition methods. 26 With this method, the movement of each tooth over the arch can be analyzed in all 3 planes of the space and measurements can be performed frequently, since digital models do not involve radiation.…”

Three-dimensional evaluation of the maxillary dentoalveolar changes with three different intraoral distalization systems: Jones Jig, Distal Jet and First Class

“…The angle formed by the intersection of these two lines was evaluated. 24 An increase of the angle indicated a distal rotation of the molar during treatment, and the decrease a mesial rotation.…”

“…following an adapted method previously described. 24 A frontal plane, perpendicular to the sagittal plane, and passing through the most anterior point of the incisive papilla was constructed by the software on the digitized models to determine the sagittal changes presented by the incisors, canines, premolars and molars 24 ( Fig. 2A).…”