Conception or design of the study; Data acquisition, analysis or interpretation; Writing the article; Critical revision of the article; Final approval of the article; Overall responsibility: MAA, BQS.
Historically, whether for research purposes or clinical monitoring, orthodontic evaluation of dental movements has been done using plaster study models and two dimensional (2D) radiographs. However, new frontiers for the diagnosis, planning and outcome assessment of orthodontic treatments have arisen, due to the revolutionary digital tools which enable a three dimensional (3D) computerized analysis of dental movements by means of digital models. However, the software for 3D analysis are often costly, resulting in limited access to orthodontists. The present study aims to describe, through a clinical case presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics, a method for the superimposition of maxillary digital models using an open-source software to evaluate dental movements.
Historicamente, a avaliao ortodntica da movimentao dentria, seja com finalidade de pesquisa, seja para monitoramento clnico, tem sido feita por meio de modelos de estudo em gesso e radiografias em duas dimenses (2D). Entretanto, com o desenvolvimento da Ortodontia digital, novas fronteiras para o diagnstico, planejamento e avaliao dos resultados dos tratamentos ortodnticos tm surgido. Os modelos digitais possibilitam uma anlise computadorizada da movimentao dentria nas trs dimenses (3D); porm, os softwares usados para as anlises 3D geralmente so onerosos e de limitado acesso aos clnicos. O presente artigo visa descrever um mtodo de sobreposio de modelos 3D da arcada dentria superior utilizando um software de livre acesso para avaliar a movimentao dentria, ilustrado por um caso clnico apresentado ao Board Brasileiro de Ortodontia e Ortopedia Facial.
Excellence in Orthodontics depends on the careful diagnosis and evaluation of treatment results. Models and its measurements should be obtained at different time-points, and compared, in order to assess and to quantify changes associated with the orthodontic treatment. Current methods for assessing dentofacial changes along the orthodontic treatment are based on the comparison of photographs taken at different time-points, superposition of cephalograms, and also direct measurements of plaster models. Indubitably, the most commonly used method for assessing tooth movement is the superimposition of serial cephalometric radiographs. However, there are some limitations and disadvantages of two-dimensional (2D) radiographic methods, such as exposition of the patient to ionizing radiation, the overlapping of bilateral anatomical structures, the magnification of the images, impairing the identification of reference landmarks and consequently tracing errors.1,2
Three-dimensional (3D) assessment of the dental and occlusal changes during an orthodontic treatment has been classically performed by the analysis of plaster models. Over recent years, plaster models have been progressively replaced by digital models.3 Digital models have many advantages when compared to traditional ones. They do not require physical storage space, present lower cost of acquisition, and are not prone to aging degradation, breakage or loss. Intra-oral scanning (which directly generates computerized digital archives of dental arches) and the scanning of old plaster models have now gained interest by orthodontist for the model analysis and diagnosis.4 The accuracy of digital models has been validated, and is considered adequate.5
The advent of digital models opened up the possibility of evaluating dental movements by superimposing models at two or more time-points, which was not possible with traditional plaster models. Thus, 3D evaluation of teeth movements is now a reality. For such purpose, it is necessary to select intraoral reference structures for the registration (3D superimposition).6,7
While the use of fiduciary lan