Digital application of three-dimensional diagnosis and treatment with a virtual articulator.

OBJECTIVE: The purpose of this article was to introduce a method for the digital application of three-dimensional (3D) diagnosis and treatment with a virtual articulator and 3D data. CLINICAL CONSIDERATION: With the use of cone-beam computed tomography (CBCT) and intraoral and facial scans, we can create a virtual articulator and evaluate the mandibular position in maximum intercuspation and centric-related occlusion for the patient with an unstable occlusion and temporomandibular disorders (TMD). Based on this, we treated a case using a digital mandibular position indicator (MPI) and fabricated a stabilization splint using a 3D printer. This approach eliminates the traditional impression or model mounting process and the analog face bow transfer. Furthermore, the design of the stabilization splint is accomplished using software. CONCLUSIONS: The approach outlined in this article offers the potential for a digital diagnosis and treatment process by seamlessly integrating CBCT, intraoral scans, and facial scans with a high degree of accuracy. This may enhance precision in diagnosis and treatment planning, especially for patients with complicated TMD, in addition to facilitating effective communication with orthodontic patients who require thorough attention. CLINICAL SIGNIFICANCE: Utilizing a virtual articulator and digital MPI for the occlusal evaluation of patients with TMD and unstable occlusion makes it possible to diagnose and analyze the occlusal condition accurately. This approach also allows for precision and efficiency in treatment.

Orthodontic treatment of an open bite after splint therapy for a patient with idiopathic condylar resorption.

In the treatment of orthodontic patients with idiopathic condylar resorption, symptoms of temporomandibular joint disorders and constantly changing occlusions caused by an instability of mandibular position make it difficult for orthodontists to confirm definitive orthodontic diagnosis and treatment plans. Therefore, these patients' temporomandibular joint (TMJ) structures need to be stabilized with splint therapy before active tooth movement to identify and maintain the true mandibular position. For some idiopathic condylar resorption patients, orthognathic surgery can cause further resorption on the vulnerable condyles of the mandible; thus, effective orthodontic camouflage treatment after joint stabilization should be considered. During the orthodontic camouflage treatment, adverse loads on the TMJ structures, which could change the position of condyles, should be avoided, and TMJ-friendly mechanics must be applied.

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.

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.

Orthodontic treatment for a patient with anterior open bite and severe condylar resorption.

A 23-year-old woman with condylar resorption and a skeletal Class II pattern and anterior open bite were treated with 4 premolar extractions and temporary skeletal anchorage devices in both maxillary and mandibular arches. Before the start of orthodontic treatment, her unstable condylar position was stabilized with a stabilization splint for 6 months. Sequential evaluation of her condylar position was performed using a mandibular position indicator. The total active orthodontic treatment time was 30 months. After treatment, her occlusion, soft tissue profile, and unstable jaw position were significantly improved. Posttreatment records after 36 months showed excellent results with a good, stable occlusion.

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.

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.