Although the Jasper Jumper is becoming a widely accepted orthodontic a
ppliance, no quantitative guidelines exist for therapy. The purpose of
this investigation was to describe the orthopedic and orthodontic cha
nges associated with Jasper Jumper therapy. A sample of 31 consecutive
ly treated Class II patients was collected from three orthodontic prac
titioners who were using the same procedures and methods. Lateral ceph
alograms were taken immediately before appliance placement and immedia
tely after appliance removal (mean interval of 0.4 years). The sample
was case matched to untreated controls based on age, sex, and mandibul
ar plane angle. The cephalograms were superimposed using anterior cran
ial base, maxillary, and mandibular reference structures to distinguis
h between growth/displacement and tooth movement. The results show tha
t the majority of Class II correction was due to dental, rather than s
keletal change. The maxilla underwent significant posterior displaceme
nt. The maxillary incisors retroclined and the maxillary molars tipped
distally. Clockwise or backwards rotation was evident for the mandibl
e. The mandibular incisors proclined significantly and the mandibular
molars translated and tipped mesially. Jasper Jumper therapy is a valu
able procedure for the correction of Class II dental malocclusions. Li
ke all other treatment modalities, there are both indications and cont
raindications for its use.