Three-dimensional imaging: The caseWestern Reserve University method

The goal of this project was to create a lifelike digital record of human dentofacial morphology. Traditionally, orthodontists have relied on a lateral and sometimes a frontal cephalometric radiograph, three facial and three intraoral photographs, and upper and lower dental study casts to capture the dentofacial morphology of their patients. Creating a unified digital record of dentofacial morphology requires all records to share the same space. Therefore, to be lifelike, all records should eventually be positioned within a computer (on-screen) representation of the three-dimensional (3D) space of the patient's head. This requirement necessitated that radiographic and facial surface morphology be rendered in 3D and that 3D study casts be converted to digital format. This article describes the Case Western Reserve University method for (1) rendering the lateral and frontal biorthogonal cephalogram pairs in 3D; (2) capturing the 3D surface of the human face; (3) converting the plaster dental cast data to a 3D digital record; and (4) integrating lateral and frontal radiographs, facial surface scans, and digital study models into a single 3D patient record. In addition, the creation of standard 3D cephalometric wireframes using the Bolton Standard subjects is described. Finally, two case reports are presented to show the use of this 3D digital record to analyze craniofacial hard and soft tissue changes brought about by Le Fort I maxillary advancement surgery. In the case reports, traditional cephalometric superimpositions are compared with 3D color-coded surface superimpositions of the preoperative and postoperative facial images. The advantages and disadvantages of this digital outcomes assessment method are discussed in this presentation of a model for the future 3D orthodontic patient record.