Early management of skeletal open bite with spring-loaded and magnetic bite blocks

The purpose of this study was to evaluate the effects of spring-loaded and magnetic bite blocks in growing individuals with skeletal open bites. The sample consisted of patients between 8 and 13 years of age randomly divided into two groups. One group was treated with spring-loaded bite blocks while the other received treatment with magnetic bite blocks. Further, a group matched for age, sex, and mandibular plane angle served as a control. The treatment effects were evaluated clinically and cephalometrically and by electromyographic (EMG) examination of the masseter and temporalis muscles after 8 months. Both appliances showed significantly (P<.05) favorable orthopedic effects. The spring-loaded bite blocks closed the existing open bite by 3.3 mm on average with a significant maxillary incisor extrusion and molar intrusion. Magnetic bite blocks produced an average of 4.9 mm of open bite closure with significant intrusion of the molars in both arches. Overall, both appliances significantly enhanced condylar growth, altered it to a more anterosuperior direction, and produced significant true forward mandibular rotation. Significant increases in masseter and temporalis muscle activity at rest and maximum clenching were noted in both groups, which could be a positive factor in retaining the achieved result. After 10 months of retention with passive bite blocks, cephalograms indicated only an insignificant relapse.