Creation of Digital Virtual Patient by Integrating CBCT, Intraoral Scan, 3D Facial Scan: An Approach to Methodology for Integration Accuracy.

ABSTRACT: The purpose of this paper was to introduce a method for creating a digital virtual patient by combining cone-beam computed tomography (CBCT), intraoral scan, and facial scan with a high accuracy of integration. CBCT scan, facial scan, and intraoral scan were obtained from initial visit. The virtual patient was created using the integration of these imaging modalities. Once the virtual patient was generated, digital workflow could be applied to initial patient consultation, diagnosis, treatment planning, virtual tooth setup, virtual treatment simulation, and post-treatment evaluation. integration of digital technology allows clinicians to improve diagnosis and treatment outcome. in addition, it allows for favorable patient communication. This technique eliminates the traditional impression process and complicated laboratory procedures for evaluating patient's occlusion during smile and habitual resting position. Based on this protocol, it is possible to create a digital virtual patient using CBCT, intraoral scan, and facial scan with a high accuracy of integration. it would be helpful for precision diagnosis and accurate treatment as well as favorable communication with patient.

Protocols for orthodontic treatment of patients with temporomandibular joint disorders.

Orthodontists often have trouble treating patients who have temporomandibular joint disorders because occlusion changes depend on the position of unstable condyles. This characteristic means the patients do not have definite criteria with which to make an accurate orthodontic diagnosis, so clinicians are unable to establish a reliable treatment plan. This article reports on the treatment of a patient with skeletal Class II relationship and condylar resorption. A stabilization splint was used before any active orthodontic tooth movement to stabilize her condylar position. Although the patient exhibited dramatically increased open bite and a retruded mandibular position after splint therapy, her occlusion and facial esthetics were resolved by orthodontic camouflage treatment with appropriate orthodontic mechanics after extraction of 4 premolars.

A digital approach to the evaluation of mandibular position by using a virtual articulator.

The purpose of this technique report was to describe a fully digital technique to evaluate the mandibular position both in centric relation occlusion (CRO) and maximal intercuspation position (MIP). The procedure transfers data relative to the position of the maxillary and mandibular dentition to a virtual articulator based on a single cone beam computed tomography (CBCT) image. A CBCT scan of the patient was obtained in CRO, and the maxillary and mandibular casts were scanned both in CRO and MIP with an intraoral scanner. The model CRO scan data were registered on the dental part of the CBCT image by using a virtual articulator program, and a virtual facebow transfer process and mounting was performed. The virtual articulator was positioned in the right and left condyle medial pole and right orbitale. The mandibular position was evaluated in CRO and MIP by superimposing the data of the mandible position in both CRO and MIP. A quantitative 3D measurement was obtained by using the grid function. Based on this protocol, it is possible to use a fully digital approach to transfer the position of a patient's maxillary dentition to a virtual articulator based on the data from a single CBCT scan and intraoral scans. This technique eliminates the traditional facebow transfer and mounting process and complicated laboratory procedures for evaluating mandibular positional changes in CRO and MIP.

Computerized ultrasonic axiographic evaluation of condylar movement in patients with internal derangement of the temporomandibular joint.

OBJECTIVES: To evaluate condylar movement during lateral excursion in individuals with internal derangement of the temporomandibular joint (TMJ) using ultrasonic axiography. MATERIALS AND METHODS: A total of 34 patients with internal derangement of the TMJ and 34 participants in the control group were examined. Mandibular functional movement was recorded by ultrasonic axiography. Three-dimensional condylar movement was measured in the working and balancing condyles. RESULTS: Significant differences in condylar movement were found between the two groups. In the group with internal derangement of the TMJ, the three-dimensional linear distances of the condylar path in a working condyle were greater than in the control group during lateral excursion. The speed of the balancing condyle in the returning path of lateral excursion was significantly greater in the group with internal derangement than in the control group. CONCLUSIONS: The results of the present study indicate that internal derangement of TMJ may affect the working and balancing condylar movements during lateral excursion.

Orthodontic Treatment Protocols for Patients with Idiopathic Condylar Resorption.

Treatment of orthodontic patients with idiopathic condylar resorption (ICR) is challenging for clinicians due to the continuous change of occlusion caused by the unstable condylar position and symptoms in the temporomandibular joint (TMJ). As an unstable condylar position can lead to confusion during orthodontic evaluation, stabilization of TMJ with splint therapy should precede orthodontic and/or orthognathic treatment. In this case report, a patient with Class II open bite and progressive condylar resorption was treated with an appropriate treatment protocol. Her condylar position was stabilized with a stabilization splint and her occlusion and facial esthetics were improved with intrusion of her maxillary posterior teeth after extraction of four premolars. Her occlusion was stable without recurrence of joint symptoms 2 years after active treatment.

Reproducibility of Facial Soft Tissue Thickness Measurements Using Cone-Beam CT Images According to the Measurement Methods.

The purpose of this study was to establish the reproducibility of facial soft tissue (ST) thickness measurements by comparing three different measurement methods applied at 32 landmarks on three-dimensional cone-beam computed tomography (CBCT) images. Two observers carried out the measurements of facial ST thickness of 20 adult subjects using CBCT scan data, and inter- and intra-observer reproducibilities were evaluated. The measurement method of "perpendicular to bone" resulted in high inter- and intra-observer reproducibility at all 32 landmarks. In contrast, the "perpendicular to skin" method and "direct" method, which measures a distance between one point on bone and the other point on skin, presented low reproducibility. The results indicate that reproducibility could be increased by identifying the landmarks on hard tissue images, rather than on ST images, and the landmark description used in this study can be used in the establishment of reliable tissue depth data using CBCT images.

Reproducibility of facial soft tissue thicknesses for craniofacial reconstruction using cone-beam CT images.

The purpose of this study was to evaluate the reproducibility of the soft tissue (ST) thicknesses at 31 landmarks using the cone-beam computed tomography (CBCT) images obtained from 20 adult subjects. Four observers carried out ST thickness measurements using Skull Measure software, and the inter- and intra-observer error rates were evaluated. Only five of 31 landmarks showed significant differences in recorded ST thickness between the observers. When excluding inexperienced observers, only one landmark showed a significant difference between the observers. Regarding the intra-observer reproducibility, the ST thickness measurements at three landmarks showed low correlation coefficients. The results of this study indicate that CBCT images can be used to measure ST thickness with high reproducibility. However, some landmarks need to be redefined to reliably measure ST thickness on CBCT images.