Double-Hinged Rapid Palatal Expander
1. The 2-hinged rapid maxillary expander is oriented perpendicular to the intermaxillary suture and is soldered to the molar and premolar bands. Two anterior extension arms (.040 wire) extend bilaterally from the premolar bands toward central incisors. The anterior extension arms are sandblasted before cementation. After cementation of the expander, the anterior extension arms are bonded to the anterior teeth with composite resin. Please note that the resin overlying the anterior extension arms should be thick enough to endure the constriction force from the expander. One day after cementation, the 2-hinged expander is activated according to the protocol of Alt-RAMEC. Each turn of the screw is 0.25 mm. Four turns is 1.0 mm. Turning toward the throat is expansion, and turning toward central incisors is constriction.
2. Alt-RAMEC or “Alternate Rapid Maxillary Expansions and Constrictions” of the maxilla is as follows.
This is a protocol for loosening the maxilla through alternate weekly rapid expansions and constrictions of maxilla. It takes 7-9 weeks to loosen the maxilla. You should be able to see the mobile or loosening maxilla while holding patient’s head with one hand and rocking his/her maxilla up and down with another hand. Also ask patient’s feel of his/her mobile maxilla.
Alt-RAMEC is as follows:
4 turns a day for one week (expansion)
4 turns a day backward for one week (constriction)
Repeat this for 6 more weeks. Ask mom to turn twice in the morning and twice in the evening.
Always keep the expander opened. An expanded maxilla allows a greater amount of maxillary protraction than a constricted maxilla. The expanded space between central incisors could be saved for relieving anterior crowding or for compensating dental effects, such as the proclined maxillary incisors due to the protraction.
3. Start protraction right after Alt-RAMEC & continue for approximately 6 to 7 months.
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