Case report of severe unilateral posterior scissors bite in children treated with clear aligners

Posterior scissors bite is a clinically common severe malocclusion, which often leads to impaired masticatory function, unilateral mastication habit and progressive facial asymmetry. This case report presented an 8-year-old boy with severe unilateral posterior scissors bite in mixed dentition, who received early interceptive orthodontic treatment with bracket-free clear aligners combined with alternating intermaxillary traction. The treatment procedures included staged expansion of dental arch width, uprighting of severely lingually inclined molars, and complete correction of posterior scissors bite. Due to poor patient compliance, treatment was interrupted and occlusal relapse occurred; thus, the traction protocol was revised and resumed. During the whole course, standardized tooth tapping training was applied to control posterior vertical height and prevent mandibular clockwise rotation. After systematic treatment, the posterior scissors bite was completely corrected, accompanied by significant improvements in dental arch morphology, dental midline alignment, anterior overjet and overbite.

For strictly indicated cases, clear aligners combined with alternating intermaxillary traction can effectively correct severe unilateral posterior scissors bite in children, with the advantages of low discomfort and superior esthetic performance, which is worthy of clinical promotion. Nevertheless, high patient compliance must be emphasized in complex pediatric cases to avoid occlusal relapse caused by treatment interruption.