Rapid Palatal Expansion on Children
With a narrow maxilla in presence or not of a posterior crossbite on a child under the age of 12, the dentist has many options from slow maxillary development with a removable appliance, a Quad-helix or else. But the dentist may also consider a rapid palatal expander (RPE) with a fixed appliance like a Hyrax or a Haas. Often when the patient is young, the maxillary molars are under erupted with short clinical crowns. This normally makes the insertion of bands more difficult and some clinicians will opt for a bonded RPE.
My appliance of choice in such cases will be a modified bonded Haas that will incorporate colored lines on the palatal cusps of the upper posterior teeth and buccal molar tubes placed in the acrylic mesial to the molars, mesial molar to facilitate access to the tube (Figure 1); the molar tubes should be as parallel as possible to the line joining the palatal cusps of the posterior teeth. Most of the litterature suggest a 6 month retention phase when the desired transverse has been reached and the molar tubes will become usefull in that 6 month period. The front teeth can be bracketed for alignment with a sectional wire and once aligned, a wire can go from the molar tubes to the front teeth, either a straight SS wire (Mulligan style) or a utility arch to manage and control the position of the upper incisors. With the bonded appliance in place, the clinician has a strong posterior anchorage and can now either intrude, extrude, protrude or retract the upper incisors with total 3D control during that 6 month retention phase, a good way tho use this retention period.