Orthopedic appliances are those appliances through which growth could be modified.
Growth modification in skeletal Class III malocclusion can be achieved by inhibition or redirection of mandibular growth and/or stimulation of maxillary growth by traction.
Extra oral appliance is an example of this orthopedic correction.
The preferred treatment for children having skeletal Class III malocclusion with retruded maxilla is the anterior movement of the maxilla where bone is added at the posterior sutures.
This can be accomplished with Delaire face mask that obtains anchorage from the forehead and chin or one of its modifications as, the suborbital face mask that obtains its anchorage from the zygomatic bones and chin.
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The face mask exerts a protraction force on maxillary splints that makes the upper arch as a single unite.The maxillary splints may be removable incorporating hooks in the canine-premolar region, cemented, or bonded, but the later causes hygiene problems and should be avoided.
An extra oral force of approximately 400 - 600 gm per side is applied by daily change of elastics that directed 30˚ downward to pull the maxilla in a downward and forward direction, to compensate for the vertical maxillary deficiency that accompanies most cases with maxillary deficiency.
It is worn for 14 hours per day.Controversy surrounds it’s optimum treatment timing: effective only during early mixed dentition, under 8 years, effective in both age groups up to 12 years, effective in both age groups in spite of being more significant during early mixed dentition, and others claimed that it protrudes the maxillary bone under 8 years while only pulls the maxillary teeth forward to compensate for skeletal malocclusion in children above 9 years.
Open Journal of Stomatology
Hussein N. Al-Khalifa