Growth period of an individual is an ideal period for the treatment of desired orthopaedic effects of skeletal jaw discrepancies. It has been reported that a deficiency in maxillary arch width is associated with Class II malocclusion.Skeletal maxillary constriction treated with rapid palatal expansion appliance has been widely reported in literature, however, other possible indications of this technique have also been proposed in addition to its prime objective of correction of posterior cross bite.¹,²

Haas³ opined that all Class II division 1 and Class division 2 patients present mandibular functional retrusion and that with Class II division 1 group the retrusion was due to constriction of maxillary dental arch, especially between the canines. It has been reported that skeletal Class II malocclusion with retrognathic mandible have benefited immensely with spontaneous forward positioning of the mandible facilitated by the widening of the constricted maxilla.^{4, 5}

This case report illustrates the treatment of a skeletal Class II malocclusion with an orthognathic maxilla and retrognathic mandible with Angles’ Class II division 1 subdivision malocclusion with maxillary constriction and severe maxillary and mandibular tooth size-arch length discrepancy. Initial treatment with rapid palatal expansion appliance to correct the maxillary constriction to promote spontaneous forward positioning of the mandible and subsequent orthodontic treatment with fixed appliance therapy resulted in a remarkable change in the patient’s dentofacial esthetics.

The soft tissue frontal and profile improved dramatically. (Figure 7a-b). The bilateral posterior crossbite was corrected. The severe increase in overjet of about 13mm was effectively reduced to 3mm and the severe deep bite was also corrected (Figure 7c,Figure 7d). Fixed maxillary and mandibular lingual retainers were given. (Figure 7e, Figure 7f). Post orthodontic treatment, normal root inclinations of the teeth and normal alveolar bone levels was observed. (Figure 8).

Figure 7a. Post-treatment extra-oral-Frontal

Figure 7b. Post-treatment extra-oral-Smiling

Figure 7c. Post-treatment intra-oral-Frontal

Figure 7d. Post treatment intra-oral – Right

Figure 7e. Post-treatment intra-oral-Upper occlusal

Figure 7f. Post-treatment intra oral-Lower occlusal

Figure 8. Post-treatment panoramic radiograph

Post treatment lateral cephalometric radiograph was taken to assess the treatment changes. (Figure 9). The changes in maxilla in the anteroposterior direction was insignificant, however an increase in the length of the mandible measured from Condylion (Co) to Gnathion (Gn) and an increase in anterior facial height was observed. Maxillary incisors were retracted dramatically by 8mm and the mandibular incisors were proclined by 3mm to camouflage the skeletal class II malocclusion.(Table 1). Effective expansion of the maxillary constriction as an end-of treatment goal was achieved. (Figure 10a,Figure 10b).

Figure 9. Post-treatment lateral cephalometric radiograph

Figure 10a. Pre aexpansion - maxillary arch

Figure 10b. Post expansion - maxillary arch

Bilateral posterior cross bite with severe skeletal Class II malocclusion is a routinely encountered malocclusion in an orthodontic practice. The probable causes for skeletal posterior crossbite could be hereditary, airway obstruction, non-nutritive sucking habits, lowered tongue position, and early loss of primary teeth. The skeletal malocclusion in the case reported had an orthognathic maxilla and retrognathic mandible with severe maxillary constriction. Some authors are of the opinion that functional appliances have no real effect on mandibular length ⁶,⁷ while others believe that mandibular growth can be increased with functional appliance treatment ^{8, 9, 10}. However, Wendling¹¹was of the opinion that a spontaneous correction of some Class II malocclusions is favoured with initial rapid palatal expansion. It has been reported in the literature that in the Class II, division 1 group, the retrusion was due to constriction of the maxillary dental arch and that in such cases, it is important to expand the maxillary arch to obtain a permanent orthopedic effect on the maxilla by releasing the mandible to move anteriorly. Literature reports too point to a strong correlation of deficient maxillary arch width and Class II malocclusion.¹²,¹³In compliance with this tenet banded Hyrax was used to expand the maxilla to permit spontaneous forward positioning of the mandible. The rapid maxillary expansion appliance widens the intermaxillary suture and increases basal bone width ^{14, 15, 16, 17}as also causes an increase in dental arch perimeter¹⁸ as had been observed in the treated case too. Post treatment cephalometric analysis revealed an increase in length of the mandible with no orthopaedic functional device given to jump the mandible. This could most probably have been attributed to the widening of the constricted maxilla with the banded rapid maxillary expansion appliance that promoted the mandible to express normal growth in an anterior direction. However mandibular growth was not sufficient enough to correct the severe anteroposterior skeletal discrepancy but the dentoalveolar compensation was maximized. The increased overjet of 13 mm was reduced to 3mm at the end of treatment most probably attributed to retroclination of the maxillary anteriors and proclination of the mandibular incisors. The mesial movement of the mandibular arch observed in this patient was favourable for the reduction in the increased overjet in compliance to the observation by Voudouris et al ¹⁹who too found mesial movement of the mandibular arch in both experimental animals and human subjects. The increased overbite was reduced to normal overbite by the flattening of the curve of Spee. A two-phase treatment therapy was instrumental in reducing the severity of the skeletal jaw discrepancy. The increase in lower anterior facial height could have been attributed to the effects of the banded rapid palatal expansion appliance that caused an initial downward and forward movement of the maxilla, together with a downward and backward rotation of the mandible. The initial increase in the anterior facial height is a temporary occurrence as long term follow-up of cephalometric analyses have shown a reversal back to normal and therefore concerns about using rapid maxillary expansion in patients with vertical growth patterns or an extremely convex facial profile are not substantiated.²⁰

The end of treatment result showed a good improvement in the transverse, anteroposterior, and vertical dimensions with markedly improved dentofacial esthetics.

A combination therapy of a banded rapid palatal expansion appliance and orthodontic treatment with pre adjusted edgewise appliance therapy was instrumental in the correction of a severe skeletal Class II malocclusion with an orthognathic maxilla and retrognathic mandible. This two-phase therapy resulted in a dramatic improvement of the facial and smile esthetics with good occlusal interdigitation that enhanced the patient’s speech, personality and self-esteem.