[Bite jumping appliance with lower lip bumper].

The removable bite jumping appliance with lower lip bumper is a new orthodontic appliance designed to correct the abnormal habit of lower lip biting children with mentalis muscle hyperactivity. Upper anterior teeth protrusion, mandible retrusion, lower anterior teeth lingual collapse and anterior deep bite usually are found in association with this lower lip biting habit, especially in the mixed dentition period (7-12 yrs). The function of this appliance is similar to the partial functional appliance. It is made into two parts: upper removable plate with anterior inclined bite plane and lower lip bumper attached to the upper plate. Three cases are discussed and compared before and after treatment. Changes in both skeletal and dental pattern were recorded in the following aspects: increase in the posterior rotation of mandible (increased SN-MP), stimulation of forward growth of the mandible (the increase is SNB value overcomes the increase in SNA, through reduction ANB), retroclination of upper maxillary teeth (reduced 1-NA), proclination of lower anterior teeth (increased 1-NB), the reduction of overjet. Additionally, the normal position of the lower lip provided by this appliance effectively corrects the lip biting with mentalis muscle hyperactivity.