CATEGORY AUSTRALASIAN DENTIST 61 CLINICAL therapy are the following: extraction of the impacted canine, shifting the maxillary midline towards the facial midline and achieve a class I occlusion in the posterior segments. The extraction of tooth 12 was necessary due to severe root destruction. Extrusion of the upper canine was unsuccessful. The ankylotic process did not allow for any root movement. Unfortunately, the upper canine had to be extracted (Figs 9, 10). Ortho therapy, however, managed to fix the occlusal and midline issues to a very reasonable extent (Fig. 11). The minimal occlusal discrepancies were further suspected to prosthodontic treatment. The extraction of the upper canine, combined with previous extraction of the lateral incisor led to a significant defect in the left maxillary region (Figs 12, 13). Despite efforts to persuade the patient to undergo bone regeneration procedures, which could lead to possible implant positioning, the patient rejected this type of treatment. His decision was further supported by the fact, that the most reliable post-ortho splinting can be done with fixed restorations, which will lead to this teeth preparation anyhow. Therefore, as a final treatment, a fixed partial denture was indicated for the teeth 15 to 25. Teeth 13 to 25 were prepared according to standard preparation guidelines for metal-free zirconia crowns. Tooth 14, which was intact but still not in a perfect occlusal contact, received occluso-vestibular veneer (made out of glass ceramic). Finally, tooth 15 also got a crown preparation, due to its big previous composite restoration. Heavy chamfer is a suggested preparation demarcation type for metal-free crowns and bridges (Fig. 14). The teeth were scanned using the Trios 4 intraoral scanner (3Shape, Denmark). Ultrapack size 000, combined with Viscostat Clear (both from Ultradent, USA) were used as retraction cords. Impression processing and further CAD-modeling was done in the Dental System Premium software (3Shape, Denmark). Special attention was paid to the bone defect, which had to be reconstructed using gingiva elements (Fig. 15). The Patient’s low smile line works in his favour in this matter. The temporary restoration was milled out of PMMA resin (Telio CAD, Ivoclar Vivadent, Liechtenstein) in the milling unit (PrograMill DRY, Ivoclar Vivadent, Liechtenstein). The appearance of the new teeth was a challenge for the patient. As they are splinted, they had to be wider (Fig.16). In addition, the minimal residual open bite required the teeth to be longer. After some time, however, the restoration was well adapted and appeared to aesthetic the patient (Fig. 17). The temporary bridge was luted with Telio Link, which is a composite temporary cement (Ivoclar Vivadent, Liechtenstein). For the final restoration a high-strength metal-free material was needed. lt has to withstand high forces, which lateral movements develop during lower jaw guidance. The mechanical challenges were even more challenging due to a missing lateral incisor, which made the edentulous area bigger. lt was concluded to do a longspan multi-unit bridge with 8 units, from tooth 13 to 25 to ensure no post-ortho teeth movement and appropriate force resisting. In addition, teeth 14 and 15 were left as single-tooth restorations. Fig. 9: Extraoral picture during ortho treatment. The low smile line works to patient’s benefit. Fig. 12: Extraoral picture after ortho treatment. The width of the edentulous area is smaller. Fig. 14: Tooth preparation for metalfree restorations (15, 13-25 zirconia ceramic crowns, 14lithium disilicate glass ceramic veneer). Fig. 16: Close up extraoral picture of the temporary restoration. Fig. 13: Intraoral picture after ortho treatment. Note the diastemas between the upper right anterior teeth, which enabled the lateral incisors with to be aligned. Fig. 15: CAD-design of the restorations, including pink aesthetics. Fig. 17: Intraoral picture of the temporary restoration. Fig. 10: Intraoral picture during ortho treatment. A large gap can be seen after the extraction of both the upper canine and the upper lateral incisor. Fig. 8: Profile picture during ortho treatment. Note the visible midline correction. Fig. 11: Profile picture after ortho treatment. The midlines are now closely aligned.
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