Superimposition of virtual models using palatal rugae and maximum habitual intercuspation.

INTRODUCTION: The superimposition of 3 dimensions (3D) digital models has been increasingly used for evaluating dental changes resulting from orthodontic treatment, and different superimposition techniques have been described. Although the maxilla has areas with greater stability for superimposition, such as the palatal rugae, there is still no reliable method for superimposing models of the lower arch. OBJECTIVE: Therefore, this article aims to describe a technique for superimposing virtual models. METHODS: To evaluate pre- and post-orthodontic treatment changes, the Geomagic Qualify 2013 software (3D Systems®, Rock Hill, South Carolina, USA) was used, with reference points in the maxilla, including the rugae and a reference area in the palate and midpalatal raphe. The lower arch was superimposed using the maximum habitual intercuspation (MHI) model as reference. RESULTS AND CONCLUSION: 3D models superimposition using palatal rugae and MHI occlusion seems to offer satisfactory results in the interpretation of clinical changes at different follow-up moments in terms of development and/or orthodontic treatment.

Superimposition of virtual models using palatal rugae and maximum habitual intercuspation

ABSTRACT Introduction: The superimposition of 3 dimensions (3D) digital models has been increasingly used for evaluating dental changes resulting from orthodontic treatment, and different superimposition techniques have been described. Although the maxilla has areas with greater stability for superimposition, such as the palatal rugae, there is still no reliable method for superimposing models of the lower arch. Objective: Therefore, this article aims to describe a technique for superimposing virtual models. Methods: To evaluate pre- and post-orthodontic treatment changes, the Geomagic Qualify 2013 software (3D Systems®, Rock Hill, South Carolina, USA) was used, with reference points in the maxilla, including the rugae and a reference area in the palate and midpalatal raphe. The lower arch was superimposed using the maximum habitual intercuspation (MHI) model as reference. Results and Conclusion: 3D models superimposition using palatal rugae and MHI occlusion seems to offer satisfactory results in the interpretation of clinical changes at different follow-up moments in terms of development and/or orthodontic treatment.

RESUMO Introdução: A sobreposição de modelos digitais em três dimensões (3D) tem sido cada vez mais utilizada como forma de avaliar as alterações dentárias decorrentes do tratamento instituído, e diferentes técnicas de sobreposição têm sido descritas. Apesar de a maxila apresentar áreas de maior estabilidade para sobreposição dos modelos, como as rugas palatinas, ainda não existe um método confiável para a sobreposição da arcada inferior. Objetivo: O presente artigo tem como objetivo descrever uma técnica de sobreposição de modelos virtuais. Métodos: Para avaliar as alterações pré e pós-tratamento ortodôntico, foi usado o software Geomagic Qualify 2013 (3D Systems®, Rock Hill, Carolina do Sul, EUA) , utilizando pontos de referência na maxila na região das rugas palatinas e uma área de referência na zona do palato e rafe palatina mediana. Já a arcada inferior foi sobreposta utilizando o modelo em máxima intercuspidação habitual (MIH) como referência. Resultados e Conclusão: A sobreposição de modelos utilizando as rugas palatinas e a oclusão em MIH parece oferecer resultados satisfatórios na interpretação das alterações clínicas entre momentos diferentes de acompanhamento, seja do crescimento/desenvolvimento e/ou resultados do tratamento ortodôntico.

Three-dimensional regional displacements after mandibular advancement surgery: one year of follow-up.

PURPOSE: To evaluate the association of 3-dimensional changes in the position of the condyles, rami, and chin at splint removal and 1 year after mandibular advancement surgery. PATIENTS AND METHODS: This prospective observational study used preoperative and postoperative scans of 27 subjects presenting with a skeletal Class II jaw relationship with a normal or deep overbite. An automatic technique of cranial base superimposition was used to assess the positional and/or remodeling changes in the anatomic regions of interest. The displacements were visually displayed and quantified using 3-dimensional color maps. The positive and negative values of surface distances in the color maps indicated the direction of the displacements. Pearson correlation coefficients and a linear model for correlated data were used to evaluate the association between the regional displacements. RESULTS: The postoperative adaptations in the chin position between splint removal and 1 year after surgery were significantly negatively correlated with changes in the borders of the posterior ramus (left, r = -0.73, P ≤ .0001; and right, r = -0.68, P = .00) and the condyles (left, r = -0.53, P = .01; and right, r = -0.46, P = .02), indicating that these structures tended to be displaced in the same direction. Even though the mean condylar displacement with surgery was less than 1 mm, individual displacements greater than 2 mm with surgery were observed for 24% of the condyles. The condylar displacements were maintained at 1 year after surgery for 17% of the condyles. CONCLUSIONS: The surface distance displacements indicated that the postoperative adaptations at different anatomic regions were significantly related.

Orthodontic management of a patient with impacted and transposed mandibular canines.

This patient report describes the treatment of a 10-year-old female with complete transposition of her impacted mandibular canines and lateral incisors. The patient had a Class I occlusion, and her mandibular lateral incisors were in crossbite with the maxillary central incisors. The treatment objectives were to create space for the impacted canines and align them with the incisors, one of which was extracted. After treatment, the appearance of the patient's teeth was improved, the occlusion was preserved, and overjet and overbite were corrected.