TREATMENT EFFECTS
OF R-APPLIANCE IN VERTICAL GROWING PATIENTS-CASE SERIES
division I malocclusion. An electronic search
in literature will reveal copious researches
about functional appliances and their effects
on mandible (14, 16, 18, 19). During treatment
with functional appliances, it has been claimed
that forward growth of the maxilla may be
inhibited (5, 22, 23). Some studies have
reported that the mandibular incisors procline
or advance significantly during functional
appliance treatment (24, 25, 29, 30, 31). In
the R-appliance group the mandible was
positioned anteriorly for construction bite. The
lingual shield of R-appliance was fabricated
with less undercut relief. The undercut relief
should be reduced to the extent that it does
not irritate the patient (32); however, it should
be reduced enough to cause mild trauma. To
avoid this trauma all patients were recurrently
instructed to posture the mandible forward.
This posturing became habitual as patients
naturally adopted a comfortable position. In
addition, the discomfort caused by reduced
relief changed patient’s compliance into an
unconscious one in the long run. Since the
patient moves the mandible forward the
protractor muscles are activated and retractor
muscles are deactivated. The activation of
protractor muscles would keep mandible
forward while the retractor muscles wouldn’t
have any significant role to pull it back. This
active protrusion has a favorable effect on the
growth and remodeling of the mandible (33).
In addition, this activation prevents headgear
effect on maxillary complex and flaring of
the lower incisors. Lack of reflex of retractor
muscles on the mandible would cause a slight
uprighting of the lower incisors.
In this study, the increase of Jarabak index
is indicative of the efficacy of R-appliance in
treatment of vertical growth pattern patients
suffering from Class II malocclusion division 1.
This was achieved by increasing the thickness
of the connection between lingual and buccal
shields which would act as a posterior bit plate.
Conclusion:
The following conclusions can be drawn on the
basis of this study’s findings:
1- R-appliance resulted in forward positioning of
the mandible in Class II division I patients with vertical
growth pattern.
2- R-appliance did not cause any proclination
of lower incisor; moreover, it even reduced their
flaring.
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