What maturational information is important for
of orthodontic head-gear treatment?
The 'Maturational Patient Report' supplied by GrowthTek clearly
assists and guides the clinician in formulating a well-timed treatment
plan. It is very important not to rely on chronologic age in
determining whether a head-gear appliance ( cervical or high-pull )
will benefit the patient.
The head-gear works best during periods of rapid growth when the
mandible is exhibiting a lot of downward and forward movement. In
this manner, the maxillary molars can be held 'in place' or moved
slightly distally as the mandible and lower molars establish a more
favorable positional relationship.
As you can see on the following chart, the period from SMI 1-3
represents an accelerating velocity period of development. The
period from SMI 4-7 represents a very high growth velocity
period and the period from SMI 8-11 represents a decelerating
As described in the background section of this web site, the amount of
maxillary and mandibular facial growth per unit of time ( growth rate )
is dependent on BOTH the maturational stage ( SMI ) and the
maturational level ( advanced vs. average vs. delayed ) of the patient.
The System of Skeletal Maturation Assessment employs a combination
of 23 stages SMIs and 14 levels of maturation, each combination of
which represents a different percentage of total maxillary and
mandibular growth completed and a different time period between
developmental periods and for the time of growth termination.
As seen on the following charts, the high velocity period of growth
( SMI 4-7 ) and the accelerating period of development ( SMI 1-3 )
demonstrate significantly more head-gear change than the decelerating
period of development ( SMI 8-11 ).
The Patient Maturational Report takes into consideration all of the
factors related to the maturational stage ( SMI ) and level, sex,
and race. The clinician can utilize this information in order to more
rationally devise an individualized treatment plan for the patient.
reference: Kopecky GR, Fishman LS. Timing of cervical headgear treatment
based on skeletal maturation. AJODO 1993;104:162-169.
Note: Please refer to the other questions in this 'Clinical Applications'
section of this web site for specific clinical information regarding
maturational timing of treatment. Also refer to the 'Background
Information' section of this web site for additional information.
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