Mandibular Gradual Deviation Caused By Improper Orthodontic Appliance

Mandibular deviation with crossbite is a common orthodontic issue affecting both function and aesthetics. A 4-year-old patient underwent MRC appliance therapy for anterior crossbite in a dental clinic. After one year, the crossbite was incompletely corrected, but the mandibular asymmetry became more noticeable. The patient presented with facial asymmetry, mandibular deviation to the left side, and a concave facial profile. No joint clicking bilaterally, but asymmetric mandibular mobility. The patient presented in mixed dentition with left-sided anterior and posterior crossbite, maxillary midline deviation to the right, mandibular midline deviation to the left, Class III molar relationship on both sides. Orthodontic treatment was primarily divided into two phases. The first phase corrected mandibular deviation. The second phase involved maxillary expansion, mandibular repositioning, and Class III intermaxillary elastics traction was applied on bilateral to correct crossbite. The total treatment duration was approximately 10 months, achieving normal overbite and overjet with essentially aligned dental midlines. The face is grossly symmetrical. This case report highlights the importance of strict adherence to orthodontic appliance indications in clinical practice. Early orthodontic treatment aims to intercept developing malocclusions during childhood growth phases, rectify skeletal and dental abnormalities, establish a healthy foundation for permanent dentition. The orthodontist should select the appropriate appliance after comprehensive consideration of the child's developmental status, with careful follow-up monitoring to implement systematic and sequential treatment.