PMC8714327_01
(a, b) Preoperative view of patient's smile.
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The patient, a 47-year-old woman, visited a private dental practice in Sao Pablo (Brazil), complaining of "a large exposure of the gums when smiling." After an extraoral, labial, periodontal, and radiographic evaluation, the presence of a marked subnasal depression, in which the upper lip lodged during a spontaneous smile, was found (Figures 1(a) and 1(b)). In addition to this, gingival exposure extending from the maxillary molar on one side of the mouth to the one on the opposite side was also found during the spontaneous smile (Figure 1(a)).
(a) Cone-beam computed tomography scan was performed to evaluate the subnasal depression and to plan the PMMA block. (b-g) Planning of the PMMA block in a 3D planning software according to the defect geometry. (h) Printed PMMA block.
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A cone-beam computed tomography (CBCT) scan was performed to evaluate alveolar bone anatomy (subnasal depression) and plan the position, size, and shape of the PMMA block (Figure 2(a)). The digital planning also allowed planning of the long term the screw positions to prevent the screws from interfering with roots or vital structures (Figures 2(b)-2(e)). The digital planning was forwarded to us for evaluation and was consistent with our expectations (Figures 2(e)-2(g)). After confirmation of the design and approval for production, the PMMA (Formslab) block was printed according to the digital data provided by using a 3D printer (Objet V260) (Figure 2(h)).
(a, b) View of subnasal depression. (c-e) The PMMA block was fixed with two titanium-based bone graft fixation screws. (f) The gingival flap was repositioned with vertical mattress sutures.
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This allowed access to the subnasal depression and the anterior nasal spine (Figures 3(a) and 3(b)). One screw was fixed between teeth 11 and 12 and the other between teeth 22 and 23 (Figures 3(c)-3(e)). Finally, the gingival flap was repositioned with vertical mattress sutures using 6-0 nylon (Figure 3(f)).
(a, b) Six months later: postoperative view of patient's smile.
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Six months after the surgery, the patient revealed a more harmonious smile than before, with reduction in gingival exposure and new support for and repositioning of the upper lip (Figures 4(a) and 4(b)).