PMC9637473_01
Clinical workflow for an occlusal vertical dimension increase in a patient showing worn dentition. ((a) and (b)) Pre-operative intra-oral occlusal photographs showing signs of cervical abrasion/erosion, slight misalignment in the upper anterior, and mild crowding in the lower-anterior areas: aesthetics appears negatively affected. (c) Panoramic X-ray image showing the pre-operative initial condition. (d) A pre-operative temporomandibular joint (TMJ MRI) scan was taken, with the patient in maximum intercuspation, showing healthy and balanced condyle-disc-fossa relationship both on the left and right side. (e) A second TMJ MRI scan was taken with patient dressing resin posterior fixed splints in order to check the TMJ status in the new mandibular position.
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The intra-oral examination revealed extensive tooth wear involving anterior and posterior teeth on both upper and lower arches, signs of cervical abrasion/erosion, slight misalignment in the upper anterior, and mild crowding in the lower-anterior areas (Figures 1(a) and 1(b)). As showed by the pre-operative panoramic X-ray image, teeth 1.7, 2.5, 2.7, 3.4, and 4.4 were missing, while teeth 1.5 and 1.6 had been previously replaced by implant-supported fixed dental prostheses (Figure 1(c)). Best, The Netherlands) with 6-channel dS Flex M surface coil. T1-weighted sagittal sequences with a 2 mm slice thickness were obtained for each TMJ. Both condyles appeared well centered within the glenoid cavities, in an anterior-superior position against the slope of the articular eminences (Figure 1(d)). Comparing the two MRIs, the condylar position appeared substantially unchanged in respect to the articular fossa (Figure 1(e)), which confirmed that the proposed OVD increase could be safely considered within the limits of a pure rotation.
Sectional clear aligner therapy and final restorations. (a) 3D alignment simulation through ClinCheck software showing attachments bonded on teeth 1.1, 1.3, 1.4, 2.1, 2.2, 2.3, 2.4, and 4.3 and interproximal enamel reduction required on teeth 1.3, 2.3, 2.4, and 2.6. ((b)-(d)) Post-operative occlusal and frontal views. The main movements achieved after the clear aligner therapy were: derotation on teeth 1.1, 1.3, 1.4, 2.2, 2.3, and 4.3; tipping increase on tooth 2.1; torque increase on tooth 2.2.
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AZ, USA) was performed. A digital impression was acquired by means of an intra-oral scanner (iTero, Align Technology) and sent to the manufacturer for the 3D alignment simulation through the ClinCheck software (Align Technology; Figure 2(a)). After the approval, aligners were received, and attachments were bonded on teeth 1.1, 1.3, 1.4, 2.1, 2.2, 2.3, 2.4, and 4.3, respectively. After one week, the patient was recalled to collect post-operative clinical photographs (Figures 2(b), 2(c), and 2(d)).