## 2 Case Report  
An adult female came to our clinic with complaints about the uncomfortable position of the lower jaw, which had been present for some months. The patient complained of fatigue of the masticatory muscles, increased tension and pain localized in the preauricular areas, and frequent headaches. Upon examination, no intra-articular noise was present when she opened her mouth. Mouth opening was full, straight, and without deviation or deflection. There were two white lines of skin at the corners of her mouth (classic hyperkeratotic dawn lines). Marked teeth wear on the occlusal surfaces of premolars and lower frontal teeth were observed (Figure 1). Metal-ceramic bridges and crowns were present on the elements 16-14, 26, 27, 35-37, 45-47 (Figure 2), and the dental examination showed that the endodontic therapies and implants present were in good condition. Diagnostic data and physical examination of the patient suggested the need of inter-occlusal splint treatment with mandibular repositioning, to reduce intra-articular pain. In this clinical case, a full digital workflow was used to design and build the device. The software used was Avantis3D (LLC Avantis3D, Bolshoy Boulevard, 42/1, Off 137/22, Skolkovo. 121205 Moscow, Russia). Full digital workflow to manufacture the splint was based on the following steps [20]:  
1. Import CBCT dicom data of the patient (taken in habitual occlusion), including the dentition and the right and left temporomandibular joints (TMJs) into Avantis3D software. Figure 1: Marked teeth wear on the occlusal surfaces: **(a)** upper occlusal view; **(b)** lower occlusal view. Figure 2: Cone beam computed tomography (CBCT) view of the orthopantomography. Matching of.stl files from intra-oral scans of dentition, with CBCT data. * Selection of condyles and TMJ fossa from CBCT data (Figure 3). * Mesh triangulation, to reproduce surfaces of condyles and articular fossa. * Calculation of intra-articular spaces width (in mm) (anterior, superior, and posterior spaces) executed by the software (Figure 4). * Virtual repositioning of the lower jaw obtained by normalizing intra-articular space width. * Virtual design of mandibular repositioning splint on the basis of mandibular repositioning. * Milling of the splint. * Insertion in the mouth. * Follow up. In the present clinical case, CBCT images revealed a narrowing of the posterior intra-articular space width, in respect to normal values established by [PERSON], that are: 1.7-2.7 mm for the anterior width; 3.1-3.9 mm for the superior height; and 3.4-4 mm for the posterior part) (Figures 3 and 4) [21, 22, 23]. The left condyle was repositioned by: \(-0.4\) mm in the transversal plane, 0.8 mm in the sagittal plane, and 0.9 mm in the vertical direction. The right condyle was repositioned by 0.4 mm, 1.2 mm, and 1.3 mm, respectively, in the three planes (Figure 4). The mandibular repositioning was automatically established by the software through a normalization of intra-articular space widths, and the exact position was visually adjusted by the clinician in the range of normal values. The software automatically established a virtual repositioning of the lower jaw and obtained normalizing posterior and superior intra-articular spaces. The new occlusal vertical dimension was then established by lower jaw rotation around a virtual hinge axis passing through the middle points of the condyles (Figure 5 evidences two red points that are the middle points of the condyles). The virtual rotation was established at 0.4 degrees (Figure 4) to obtain the normalization of superior and posterior space widths. The middle points of the condyles (represented as red points in Figure 5) are determined automatically by the software on the CBCT 3D reconstruction, connecting the right and left poles of each condyle, thus individuating the middle point of the major condylex axes. This full digital procedure provides a virtual repositioning of the lower jaw, visually and technically controlled by the clinician, aimed to unload the bilaminar zone in the two TMJs.