الفهرس 
Class II division 1 Malocclusion
A randomized controlled clinical trial was performed.Only 14 pages are availabe for public view
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Abstract
The use of functional appliances in developing class II division 1
malocclusion is essential to produce desirable skeletal and dentoalveolar
changes. These appliances act by eliminating soft tissue dysfunction acting on muscles of tongue, lips and cheeks and simultaneously correct tooth and jaw position. If dental malocclusions occurring in mixed dentition period are managed timely, they can be reduced in severity or even removed. A wide variety of functional appliances has been introduced to treat developing calss II malocclusions by stimulation of mandibular growth. The available researches showed that short-term evidence indicates that the
activator (monobloc) appliances are effective in correcting Class II
malocclusion. The main disadvantages were complex construction, being
bulky, more prone to breakage and less significant effect on soft tissues
dysfunctions. Trainer for kids (T4K) was introduced by farell as a simple
treatment system that combines the easiness of use and the possible positive effects of myofunctional training appliances in the early treatment of Class II malocclusions.
The main aim of this study is to assess and compare the efficacy of
preorthodontic trainer versus monoblock in treatment of developing class II division 1 mixed dentition both clinically and radiographically. The present study was conducted on forty patients (17 males and 23 females) with class II division 1 malocclusion indicated for growth modification by functional appliances. All patients were healthy children at active growth period from 7 to 11 years with a mean of 9 years with overjet >4.5 mm and ANB angle greater than 4 degree. A total of 40 appliances were inserted; 20 T4K appliances for group I and 20 activator appliances for group II. All patients (except 2 lost during follow up period) were followed up clinically and radiographically for
9 months. Improvement in the skeletal Class II features was detected in both
groups. 37 patients were treated and only one patient torn his T4K.
Significant favourable skeletal changes were achieved with both
appliances assisted in correction of class II malocclusion skeletally in both groups but Activator was significantly more effective with greater increase in SNB angle and more reduction in ANB angle but no significant difference
for SNA angle. characteristic skeletal effects of activator were consistent
with many studies but skeletal effects of T4K were in accordance with some
studies and inconsistent with others.
For dentoalveolar changes, improvement of overjet in both groups was
reported due to lingual tipping of upper incisors indicated by decrease of upper incisor to SN planee angle measurments, mandibular incisors
proclination manifested by increased lower incisor to mandibular plane angle measurments and forward growth of the mandible. These changes are in
accordance with previous studies regarding the Activator and the Trainer which reported favourable dentoalveolar changes but were found favoring a greater amount of overjet correction with the activator appliances compared with T4K appliances.
Better soft tissue changes were achieved with T4K appliance as shown
by intergroup comparison. Greater significant improvement in interlabial
distance and upper lip length was evident in T4K group when compared to
activator group. The reason for better soft tissue changes in T4K group could
possibly be due to myofunctional training system incorporated in T4K
appliance and awareness of the lip seal problems during the initial training with the appliance.