Pacific Coast Society of Orthodontists Bulletin Summer 2017 - 64

Presentation Summary

Case #3: 7-Year-Old Male
 Diagnosis: Class II Division 1 malocclusion
with mandibular retrusion, excess overjet
and overbite, mild spacing, and lower incisor
proclination.
 Treatment rendered: Bionator treatment for
two years, followed by comprehensive orthodontic treatment with fixed appliance.
 Treatment progress: Treatment with removable functional appliance for two years
improved the A-P molar relationship. Overjet
was overcorrected to an edge-to-edge incisal
relationship together with an improvement
in overbite.
 At age 13, the remaining dental malocclusion
and excessive overbite were corrected with
comprehensive orthodontic treatment with
fixed appliance.
Advantages of Fixed Functional Appliances
 Appliance is fixed to the dentition, so no
patient compliance is necessary.
 Treatment is applied continuously for 24
hours a day, so treatment time is shorter.
 Possibilities of fossa remodeling.
Questions to Be Addressed Regarding Class II
Orthopedic Treatment
 Can we stimulate mandibular growth and
retain it after completion of growth? Can
this be done with functional appliances?
 Can we restrain maxillary growth? There is
anatomical difference between mandibular
and maxillary growth as the mandible simply
grows at the condyle, but the maxilla is composed of multiple sutures.
Animal studies have shown that protrusion of
the mandible can stimulate proliferation of
condylar cartilage that may eventually lead to

additional mandibular growth. However,
this does not mean that the mandible will be
larger at the end of the growth period. Some
prospective clinical trials have demonstrated that
functional appliances can modify growth, while
others reported that it is limited to dentoalveolar
changes. Another study by Marisco et al. conducted randomized clinical trials and concluded
that functional appliances increased mandibular
length but did not influence the Class II pattern
to a clinically significant degree, with no forward
positioning of mandible. Therefore, it is important to pick the type of Class II patients with
forward and upward mandibular growth for
effective use of functional orthopedics.
Does Age Make a Difference in Functional
Appliance Treatment?
According to a study by Ghislanzoni and Franchi,
headgear works best before the peak of the
growth spurt because maxillary growth depends
on sutural growth. However, if you want to accelerate mandibular growth, it should be done during the peak pubertal growth period. In addition,
dental compensation increased during prepeak
and postpeak growth periods, but it was minimal
during the peak growth period. Therefore, Dr.
Ngan recommends functional appliances such
as Herbst or MARA be used during the growth
peak to allow minimal dental compensation and
maximum orthopedic changes. The treatment
then needs to be retained, with the mandible in
a forward position, for the permanent teeth to
erupt into a more Class I molar relationship and
interdigitation.
Dr. Ngan does not have any conflicts of interest
or commercial interests. 

PCSO Bulletin  Summer 2017

Table of Contents for the Digital Edition of Pacific Coast Society of Orthodontists Bulletin Summer 2017