The 20 Principles of the Alexander Discipline, Volume 3. R.G. "Wick" Alexander

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Fig 1-5 The mandibular first molar brackets are angulated to 0 degrees.

      • Archwires: A reverse curve of Spee is placed in both archwires.

      • Elastics: Anterior and buccal box elastics should be used.

      • Squeezing exercises: The patient should be taught squeezing exercises to improve occlusal forces. The patient should also be advised to chew gum to encourage such occlusal forces.

      • Extractions: Extractions may be necessary, depending on the specific conditions of the case.

       Reference

      1. Parks L. Masticatory exercise as an adjunctive treatment for hyperdivergent patients. Angle Orthod 2007;77:457–462.

       Case 1-1

      Overview

      Although a conscientious practitioner can learn from every case treated, certain cases stand out as especially educational when the patients display unique conditions and then respond to treatment in unexpected ways. Such a patient was a 16-year-old girl who presented with an extremely high-angle, Class III skeletal pattern (Figs 1-6a to 1-6c). Dentally, she had a Class III molar relationship, a right posterior crossbite, and an anterior open bite of 4 mm (Figs 1-6d to 1-6h). She had a mandibular arch length discrepancy of 5 mm. Figures 1-6i and 1-6j show the pretreatment cephalometric tracing and panoramic radiograph. Because she was near adulthood, maxillofacial surgery was considered, but because it was a borderline case, the treatment objectives would have a chance to be successful without surgery.

      Examination and diagnosis

      This 16-year-old girl had an extremely vertical skeletal pattern (SN-MP of 49 degrees), a transversely constricted maxilla, a dental open bite (4 mm), and a tongue thrust. Skeletal surgery (three-piece maxillary osteotomy) was discussed, but we agreed to attempt nonsurgical and nonextraction treatment first.

      Treatment plan

      Initially, a fixed palatal expander was used. The patient was instructed to turn the appliance every other day because of potential discomfort. She was also asked to squeeze her teeth together as often as possible. Rather than wear a face mask, she would wear Class III vectored elastics.

      Evaluation

      Unexpectedly, the rapid palatal expander (RPE) created a 3-mm diastema between the central incisors and increased the open bite by another 5 mm (Figs 1-6k to 1-6m). The buccal tipping of the molars caused premature cusp contacts, thus creating a larger open bite. The good news was that this situation was temporary.

      Discussion

      After transverse expansion, the next goal was to create a normal occlusion. This was accomplished with Class III vectored box elastics (Figs 1-6n to 1-6r), squeezing exercises, and tongue control. Significant interproximal enamel reduction was performed on the mandibular anterior teeth. The combination of these factors controlled IMPA. Finishing wires (17 × 25 SS) were then placed on both arches (Figs 1-6s to 1-6w), followed by finishing elastics 7 months later (Figs 1-6x to 1-6bb). Figures 1-6cc to 1-6ll show the posttreatment results.

      Long-term stability

      Open bite malocclusions are difficult enough to maintain in the long term, but when a Class III nongrowing skeletal pattern is added to the mix, the challenge is even greater. The patient continues with her tongue exercises and sleeps in a wraparound retainer (which has a small hole in the anterior part of the acrylic for her tongue).

      Interestingly, the occlusion improved with time (Figs 1-6mm to 1-6ww). My assumption as to why is that the final occlusion is in a stable position and the oral and intraoral muscular tissues are functioning normally.

       Case 1-1

Figs 1-6a to 1-6c Pretreatment facial views showing a Class III tendency profile.

Figs 1-6d to 1-6f Pretreatment intraoral views. The patient has a 4-mm open bite and Class III molar relationships.

Figs 1-6g and 1-6h Pretreatment occlusal views.

Fig 1-6i Pretreatment cephalometric tracing.

Fig 1-6j Pretreatment panoramic radiograph.

Fig 1-6k Frontal intraoral view after expansion with an RPE.

Figs 1-6l and 1-6m Occlusal views after expansion.

Figs 1-6n to 1-6p Intraoral views 14 months into treatment: maxillary and mandibular 17 × 25 TMA archwires; lateral box Class III elastics are begun.

Figs 1-6q and 1-6r Occlusal views 14 months into treatment.

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