PMC7077940_01
Pretreatment records (at 21 years and 3 months of age): A-I) extraoral and intraoral photographs; J) lateral cephalometric radiograph; K) panoramic radiograph; L-M) cone-bean computed tomography to assess the supernumerary teeth in the maxillary arch.
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Front and profile facial photographs showed a symmetrical face, convex profile and protruded and incompetent lips (Fig 1). Panoramic radiograph confirmed the absence of mandibular canines on both sides, and two midline supernumerary teeth were detected at the maxillary central incisors region (Fig 1K). Cone-beam computed tomography showed no pathological problems in the root structure of maxillary central incisors on either side (Figs 1L to 1M).
Series of intraoral photographs taken during treatment: A-D) start of treatment; E-H) molar intrusion; I-L) leveling of the maxillary arch; M-P) leveling of the mandibular arch; Q-T) space closure of the maxillary arch; U-X) detailing.
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After extraction of two supernumerary teeth, a transpalatal arch was inserted in the maxillary arch (Figs 2A - 2D). Two months after leveling and alignment, 0.016 x 0.022-in stainless steel (SS) archwire was installed to initiate the vertical anchorage control of the maxillary molars, using an elastomeric chain from the TADs to the segmental wires (Figs 2E - 2H). After 4 months of molar intrusion and bilateral maxillary first premolars extraction, the maxillary lingual brackets (STb , Ormco, Glendora, CA, USA) by indirect bonding system and the mandibular labial brackets (iPass , Dentaurum, Pforzheim, Germany) by direct bonding system were placed, then the alignment was initiated by inserting 0.014-in NiTi wires in both arches (Figs 2I - 2P).The wire size was increased to 0.016 x 0.022-in NiTi. For space closure and anterior teeth retraction of the maxillary arch, a loop mechanic with 0.017 x 0.025-in SS was used (Figs 2Q - 2T). Detailing and finishing were achieved using 0.016 x 0.022-in beta-titanium-molybdenum wire in both arches (Figs 2U - 2X). In the evaluation using a jaw movement recording system with six degrees of freedom (Gnathohexagraph System, version 1.31; Ono Sokki, Kanagawa, Japan), a smooth increase in the condylar movement was observed during protrusive or lateral excursion (Fig 5, Table 2).The interincisal distance on maximum opening without pain was maintained at 45 mm.
Posttreatment records (at 24 years and 2 months of age): A-I) extraoral and intraoral photographs; J) lateral cephalometric radiograph; K) panoramic radiograph.
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Compared to the pretreatment photographs, the posttreatment photographs showed retraction of the upper and lower lips, which subsequently improved the patient's facial profile and the relief of lip incompetence (Figs 3A-3I). Although the missing mandibular canines were substituted by mandibular first premolars, well-aligned arches and good interdigitation were achieved, with Angle Class I molar relation (Figs 3A-3I). The posttreatment panoramic radiograph showed acceptable root parallelism, with no significant root resorption, except for slight apical root resorption of the maxillary right second premolar (Fig 3K).
Superimposed pretreatment (black line) and posttreatment (red line) cephalometric tracings: A) superimposed on the sella-nasion plane at the sella; B) superimposed on the palatal plane at the ANS; C) superimposed on the mandibular plane at the menton.
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Superimposition of the pre- and posttreatment cephalometric tracings showed that the maxillary and mandibular incisors inclination was normalized (Fig 4).
Condylar movement and incisal paths recorded using a jaw movement recording system with six degrees of freedom. The red lines indicate the opening phase, and the blue lines indicate the closing phase: A) pretreatment, B) posttreatment.
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In the evaluation using a jaw movement recording system with six degrees of freedom (Gnathohexagraph System, version 1.31; Ono Sokki, Kanagawa, Japan), a smooth increase in the condylar movement was observed during protrusive or lateral excursion (Fig 5, Table 2).The interincisal distance on maximum opening without pain was maintained at 45 mm.
Post-retention records (at 26 years and 7 months of age): A-F) extraoral and intraoral photographs, G) lateral cephalometric radiograph, H) panoramic radiograph.
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Good facial aesthetics and acceptable occlusion were maintained after 29 months of retention (Figs 6 and 7).
Superimposed posttreatment (red line) and post-retention (green line) cephalometric tracings: A) superimposed on the sella-nasion plane at the sella; B) superimposed on the palatal plane at the ANS; C) superimposed on the mandibular plane at the menton.
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Good facial aesthetics and acceptable occlusion were maintained after 29 months of retention (Figs 6 and 7).