Despite these advancements, it is still common to observe clinicians—especially at conferences—attempting to correct open bites primarily through anterior extrusion. Unfortunately, this method has a high tendency for relapse, and recurrence of the open bite is often seen after treatment. In contrast, when the correction is achieved through molar intrusion, the natural masticatory forces tend to support and maintain the closure, making relapse significantly less likely.^{6, 7}

It is important to emphasise that aligners are an ideal appliance for achieving vertical control. The physical thickness of the aligners, combined with occlusal forces during function, can aid in the intrusion of posterior teeth.^{8, 9}

After the 20^th aligner, we initiated the reset phase, pausing treatment to rescan the patient and replan the final phase. At this stage, crowding had been resolved, and the open bite had been closed, although additional posterior intrusion was still needed to establish a stable correct overbite. This mid-treatment refinement is crucial to ensure precise fit and continued accuracy of the aligners.

After the reset phase, which involved treatment with 12 aligner pairs, treatment continued with a focus on further maxillary posterior intrusion to fine-tune the vertical correction (Fig. 9). The second round of aligners targeted case finishing with the specific objectives of improving posterior intercuspation, achieving precise midline correction and enhancing sagittal relationships through posterior IPR and the bilateral use of Class III elastics (Fig. 10).

Final outcomes
After 18 months of treatment, including the reset phase and refinements, the patient exhibited significant extra-oral improvements, including a more harmonious smile arc, increased incisor display at rest and notable facial profile enhancement driven by effective mandibular auto-rotation (Fig. 11). Intra-orally, the results included Class I molar and canine relationships, proper alignment and levelling of both arches, an ideal overjet and overbite, and coinciding maxillary and mandibular midlines (Fig. 12).

Beyond the occlusal and aesthetic improvements, vertical control had delivered significant facial changes, including a shortening of the lower facial third, improved upper and lower lip support, and an advancement of the chin by 5 mm (Fig. 13). Importantly, all of these changes were achieved without exacerbating the initial root resorption, as confirmed by the final panoramic radiograph (Fig. 14). The final cephalometric radiograph and tracing confirmed the successful treatment outcome, showing clear evidence of mandibular auto-rotation and a shortened lower facial third, contributing to improved facial proportions (Fig. 15).

Moreover, the final virtual articular mounting demonstrated a precise match between the patient’s maximum intercuspation and true arc of closure. This alignment reflects the achievement of orthopaedic stability—a sine qua non for long-term dental health, functional occlusion and the stability of the treatment results (Fig. 16).

Case 2: Patient with a complex malocclusion and temporomandibular disorder signs and symptoms

A 23-year-old female patient presented with persistent signs and symptoms of temporomandibular disorder (TMD) as her chief complaint. After seeking multiple professional opinions, she came to our clinic for a third evaluation. The patient exhibited a symmetrical facial structure, a bimaxillary retrusive profile and a mildly increased lower facial third. On smiling, dental crowding became apparent (Fig. 17).

The active orthodontic treatment was carried out with 60 maxillary and mandibular aligners, delivered in phases: 30 aligner pairs or the initial phase, 18 aligners for the first refinement and 12 aligner pairs for the second refinement. In the final phase of treatment, 3⁄16 in., 4.5 oz intermaxillary elastics were prescribed to improve the Class II dental relationship and enhance final intercuspation. The total treatment time was 18 months, including periods where the patient wore Essix-type retainers between refinement phases.

Final outcomes
Extra-orally, enhanced smile aesthetics was achieved thanks to the maxillary arch expansion and resolution of crowding. There was also a shortening of the lower facial third, improved chin projection and enhanced lip support (Fig. 30).

Intra-orally, both arches showed improved shape (expanded by approximately 1.5 mm per side), well-aligned and levelled teeth, and resolution of the initial crowding. Class I molar and canine relationships were achieved bilaterally, as well as good final overjet and overbite. The maxillary incisors were proclined (U1–PP from 93° to 106°), and the mandibular incisors were slightly retruded (IMPA from 99.4° to 97.2°). The midlines were centred (Fig. 31).

The post-treatment panoramic radiograph showed good root parallelism and no worsening of the pre-existing root resorption or periodontal condition (Fig. 32). The final cephalometric radiograph and tracing showed that, although the patient retained a Class II skeletal pattern, the values had improved owing to mandibular auto-rotation (ANB from 6.9° after splint therapy to 4.4° at the end of treatment). This auto-rotation had also improved the vertical measurements between the end of splint therapy and the end of treatment: maxillary inclination (SN–OP) had decreased from 18.6° to 16.2°, Ricketts’ facial axis from 92.7° to 91.4° and Jarabak’s sum of angles from 392.0° to 387.6° (Fig. 33).

Finally, and most importantly, orthopaedic stability had been achieved, and there was no discrepancy between maximum intercuspation and centric occlusion (Fig. 34). There was also complete resolution of the TMD symptoms.

Case 3: Post-aligner treatment case with signs and symptoms of TMD

This case involves a 29-year-old female orthodontist who was completing a fellowship at our clinic. During her time with us, she began to suspect that her own symptoms might be related to her occlusion. Although she had previously undergone orthodontic treatment, she was now experiencing TMJ discomfort. After observing the successful treatment of several patients for similar TMJ issues, she approached us for a diagnostic evaluation of her own case.

Final outcomes
Extra-orally, two aspects are worth highlighting: the significant improvement in the smile, in that the patient no longer showed posterior gingiva, owing to intrusion of the maxillary posterior teeth; and the slimmer facial appearance, thanks to muscle relaxation and reduction in the size of the masseter muscles (Fig. 47). Intra-orally, Class I molar and canine relationships had been achieved, and the anterior open bite had been closed, resulting in proper overjet and overbite. The positive torque applied to the maxillary and mandibular posterior segments had improved the arch form. The maxillary incisors were proclined (U1–PP from 105° pretreatment to 112° post-treatment) and the mandibular incisors retroclined (IMPA from 98° pretreatment to 93° post-treatment; Fig. 48).

The final panoramic radiograph showed good root parallelism and confirmed that all treatment objectives had been met without root resorption or harm to periodontal health (Fig. 49). The final cephalometric radiograph and tracing confirmed the mandibular auto-rotation: a facial axis of 95° pretreatment to 97° post-treatment and an anterior facial height of 117.5 mm pretreatment to 115.9 mm post-treatment (Fig. 50).

Finally, the treatment concluded with orthopaedic stability (maximum intercuspation coincided with centric occlusion), as well as with improved condylar position and morphology. The patient was also completely free of TMD symptoms (Fig. 51).

Conclusion

Vertical control using aligners and mini-screws has proved to be highly effective for closing anterior open bites, producing stable long-term results. The use of an aligner system that incorporates the patient’s arc of closure into its planning software is particularly valuable for accurate planning of mandibular rotation and the precise positioning of the incisors. By utilising the arc of closure during treatment planning, we can avoid unnecessary back-and-forth movements, which typically lead to the use of more aligners, an increased number of refinements and longer treatment duration.