Q. Why use a maxillary expansion appliance (MEA) in all mixed dentition cases?

A. Aside from a few cases that do not require maxillary expansion, such as Class I spacing, the treatment of the majority of mixed dentition cases requires using a maxillary expansion appliance (MEA). This is because treatment of every class of malocclusion (I, II, and III) is facilitated by an increase in maxillary transverse dimension. Furthermore, the MEA is a rigid appliance that provides solid anchorage to the maxillary permanent 1st molars for the correction of anterior open bite or deep overbite cases. Stabilizing the molars prevents iatrogenic side effects such as distal tipping of the molars.

Q. Why use a two-banded appliance instead of the traditional four-banded one for maxillary expansion?

A. The two-banded appliance is preferred over the more traditional four-banded one because it is as effective* and more flexible. A major problem of the four-banded expander is the inability to adjust it, which can lead to unwanted side effects. For instance, it can over-expand the anterior portion of the buccal segments, while the posterior teeth need more expansion. The two-banded appliance has adjustable arms that can be moved away from the buccal segments on either side as maxillary expansion progresses, making it possible to expand symmetrically.  

*Lamparski DG Jr, Rinchuse DJ, Close JM, Sciote JJ. Comparsion of skeletal and dental changes between 2-point and 4-point rapid palatal expanders. AJODO 123:321-8, 2003.

Q. Why expand the mandibular arch?

A. Expansion of mandibular arch is needed because of the following:

• It re-adapts the position of the mandibular permanent 1st molars to the expanded position of the maxillary molars. Without mandibular expansion, maxillary expansion of about 8 mm or more moves the maxillary molars past the mandibular occlusal table, creating a buccal crossbite condition. Dentoalveloar expansion of mandibular arch prevents this from occurring, and provides the opportunity for additional maxillary expansion of up to 12 mm or more in patients that would benefit from it.

• Expansion of mandibular arch provides the needed space for alignment of lower incisors and eliminates the need for extraction of primary or permanent teeth in cases of arch length deficiency.

Q. Does it become visually noticeable when the maxilla is expanded excessively (beyond 10-12mm)?

A. Expansion of the maxilla can temporarily result in the upper arch appearing over-expanded, particularly in the deciduous canine areas. This visual effect resolves within 2 months after the adjustable arms of the MEA are moved away from the deciduous canines. After the upper arch has been bonded with brackets and the primary teeth are aligned, the mesially extended arms of the MEA can be removed with a carbide burr. This allows the maxillary arch to assume its optimal shape.

Q. Is bonding of primary molars and canines necessary?

A. Yes, particularly if the treatment objective is to avoid a 2nd phase of treatment. Bonding of the primary molars and canines addresses the dentoalveolar component of malocclusion, i.e. deficient space, overjet, open bite and overbite.

Q. When are the primary teeth bonded?

A. Roughly 2-3 months into the treatment or when the expansion phase is nearly completed. Bonding of the deciduous teeth can be done sooner if maxillary expansion causes an excessive diastema between the permanent incisors. Usually both maxillary and mandibular arches are bonded simultaneously. Bonding of the mandibular arch is postponed in deep overbite cases to allow time for bite-opening to take effect.  The decision to bond one arch or both arches can also be left to the patient. Primary teeth that are loose should be left to exfoliate and not bonded.   

Q. What does the term “E-I tips” refer to?

A. “E” refers to extrusion and “I” represents intrusion. E tips are employed for correction of anterior open bites and I tips are used in the treatment of deep overbite cases.
The E-I tips provide the most convenient, painless and quick method for extrusion and intrusion of permanent incisors. To facilitate extrusion, E tips are applied during bonding of the brackets on the maxillary and/or mandibular 1st primary molars and canines.  Accordingly, the brackets are bonded at a slightly rotated/tilted position so that the mesial side of the slot is pointed towards occlusal surface. Once a resilient arch wire, i.e. Nickel-Titanium, is tied into the brackets, it will gently extrude the permanent incisors. Conversely, intrusion of the permanent incisors is accomplished by bonding the brackets on the primary 1st molars and canines at a slightly tipped angle so the mesial side of the slot is facing more gingival than the distal side. An arch wire that is employed in such a configuration will cause intrusion of the permanent incisors.

Q. For how long are the Primary teeth bonded/bracketed?

A. Roughly 4-5 months to allow for leveling and alignment, correction of open bite or deep overbite, and development of adequate space for eruption of the permanent teeth in each quadrant (25 mm minimum).

Q. What kind of brackets are used for bonding to the primary teeth?

A.One can use bicuspid brackets to bond to primary teeth. However, they have the adverse effects of not conforming well to primary teeth, being more difficult to employ E-I tips with, and being painful when debonded. “Debra” brackets are a preferable option to bicuspid brackets, as they are specifically designed for bonding to the primary teeth. In addition to their better fit, they provide E-I rotational flexibility, and ease of removal when the primary teeth are wiggly.

Q. When are the MEA and LLA removed?

A. The MEA is removed when a) the maxillary permanent incisors are well aligned with 1-2mm of additional space between the lateral incisors and primary canines, b) the maxillary permanent molars are over-expanded to account for the decompensation of their buccal tipping, and c) when a rigid rectangular steel arch wire, i.e., .017 x .025” can be inserted in a 2x4 configuration upon removal of the primary tooth brackets.
Likewise, the LLA can be removed once lower incisor alignment is complete. At this time the brackets on the deciduous teeth are debonded and a rectangular stainless steel arch wire is engaged in a 2x4 configuration.

Q. Is overcorrection necessary in the treatment of mixed dentition cases?

A. Absolutely. It is particularly important to overcorrect maxillary expansion in the cases that maxillary molars are originally tilted buccally or are in lingual crossbite. We recommend an extra 25% of maxillary expansion. In Class III cases, we strive to achieve 3.5-4 mm of positive overjet at completion of treatment.

WARRANTY AND RETURN POLICY

Q. What is your return policy?

A. Within 90 days of the purchase date you can request a refund for any un-used product. Contact: sales@mdorthod.com Please include your order # to expedite the return.

Q. What is your warranty?

A. One Year from the date of purchase. If you find any defect or need assistance with your product, contact us at: info@mdorthod.com .

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