Kuster R, Ingervall B
Orthodontic Clinic, University of Bern, Switzerland.
Eur J Orthod. 1992 Dec;14(6):489-99. doi: 10.1093/ejo/14.6.489.
The treatment of anterior skeletal open bite was studied in two groups of children. The children of one group wore a removable spring-loaded bite-block in the lower jaw for one year. The bite-block exerted an intrusive force on the upper and lower posterior teeth. The children of the other group were treated for 3 months with bite-blocks with repelling magnets. These bite-blocks were cemented on the posterior teeth of both jaws. The effects of treatment were monitored by measurement of the bite-force (group with spring bite-blocks only), by electromyographic recording of the activity of the temporal and masseter muscles, and by X-ray cephalometry. Recordings were made before, during, and at the end of the treatment, and at a follow-up observation. The bite-force increased during the first months of treatment, but was then unchanged. The activity of the masseter muscle during maximal bite also increased in the first part of the period of treatment with a spring bite-block. In the group treated with magnetic bite-blocks, there was an increase in the resting activity of the masseter muscle and in the chewing activity of the anterior temporal muscle. The effects of the treatment on bite and facial morphology were less marked in the group with spring bite-blocks than in the group with magnetic bite-blocks, with an average improvement of the overbite of 1.3 mm with the spring bite-block therapy. In the group with magnetic bite-blocks, the average improvement in overbite was 3 mm. This was thought to be due to anterior rotation of the mandible and increased eruption of the incisors. The mandibular rotation was a result of intrusion of the upper and lower posterior teeth and possibly also increased mandibular growth. A follow-up of the cases treated with magnetic bite-blocks revealed a tendency for the beneficial effects of the treatment to relapse which possibly could be counteracted by a long phase of active retention.
在两组儿童中对前牙骨骼性开牙合的治疗进行了研究。一组儿童在下颌佩戴可摘式弹簧加载咬块一年。该咬块对上下后牙施加垂直向力。另一组儿童使用带有排斥磁铁的咬块治疗3个月。这些咬块粘结在上下颌的后牙上。通过测量咬合力（仅弹簧咬块组）、颞肌和咬肌活动的肌电图记录以及X线头影测量来监测治疗效果。在治疗前、治疗期间、治疗结束时以及随访观察时进行记录。咬合力在治疗的最初几个月增加，但随后保持不变。在使用弹簧咬块治疗期间的第一阶段，最大咬合力时咬肌的活动也增加。在使用磁性咬块治疗的组中，咬肌的静息活动和颞肌前部的咀嚼活动增加。弹簧咬块组的治疗对咬合和面部形态的影响不如磁性咬块组明显，弹簧咬块治疗使覆牙合平均改善1.3毫米。在磁性咬块组中，覆牙合平均改善3毫米。这被认为是由于下颌骨向前旋转和切牙萌出增加所致。下颌骨旋转是上下后牙垂直向压低以及可能下颌骨生长增加的结果。对使用磁性咬块治疗的病例进行随访发现，治疗的有益效果有复发的趋势，这可能可以通过较长阶段的积极保持来抵消。
