Diagnosis and Treatment Planning
The treatment records for one patient are used here as an example of the advanced diagnostic facilities provided by systems such as Onyx Ceph (Image Instruments Ltd., Chemnitz, Germany). The treatment of most of the cases presented in subsequent chapters was planned using the methodology described below.
An 18-year-old patient presented for an orthodontic evaluation. She had undergone previous orthodontic treatment involving removal of two upper first premolars to align the upper canines. Post-treatment records following the first orthodontic treatment showed a left-sided unilateral crossbite as an initial sign of maxillary deficiency. In addition, she had a reduced overjet and overbite, which was at risk for worsening with further growth given the patient’s class III tendency. The current records showed a bilateral crossbite and anterior edge-to-edge relationship as a result of the previous treatment and additional craniofacial growth.
The patient’s chief complaint was a protruding chin, which was accentuated by a maxillary deficiency. After initial decompensation, it became clear that the underlying class III malocclusion should ideally be treated with an orthognathic approach ( Fig. 4.5 : 21, 22).
After superimposition of the cephalogram and the clinical photograph, a prediction tracing was obtained with a “visualized treatment objective” (VTO). Analysis of the three-dimensional models allowed further planning in this case.
Case Study 4.1 (Fig. 4.5)
Patient: F. K., female, age 18.
Diagnostic records: models, panoramic radiograph, lateral cephalometric radiograph, intraoral/extraoral photographs.
Main findings: class III malocclusion due to mandibular excess and relapse after previous orthodontic treatment, combined with residual craniofacial growth.
Treatment aims: combined orthodontic surgical treatment to improve the profile and the stability of the treatment result.
Appliances: self-ligating brackets, Hybrid RPE (see p. 135).
Archwire sequence: 0.012 round wire, superelastic; 0.016 round wire, superelastic, 0.016 × 0.022 superelastic, 0.018 × 0.025 superelastic and 0.019 × 0.025 stainless-steel archwires.
Alternative treatment strategy: opening of spaces in the upper jaw for later replacement of the previously extracted upper first pre-molar teeth (14 and 24), or alternatively extraction of two corresponding premolars in the lower jaw for further dental compensation.
Active treatment time: 11 months.
Retention: three-dimensional retention.
Errors and risks:
It might be prudent to consider a non-extraction approach for the upper jaw when planning treatment for growing patients with a class III malocclusion on a class III skeletal base. Particularly when undertaken in the upper jaw, extractions only often lead to poor treatment outcomes. Maxillary extractions alone are generally not indicated for class III cases.