Management of the transverse dimension (expansion) with microscrews (TADS)

Resumen

An effective alternative for the correction of the skeletal transverse maxillary deficiency is through expansion with the use of Microscrews or temporary skeletal anchorage devices (TADS). With this technique we can perform separation or disjunction of the midpalatal suture so the maxillary processes may separate to correct the transverse maxillary discrepancy in relation to the lower arch without dentoalveolar compensation. This means that pure bone expansion will be performed avoiding dental and/or alveolar compensations that may be deceiving regarding the amount of expansion required for the correction or alignment of the arches. Two or four microscrews are placed directly bilaterally on the palate so that afterwards an acrylic plate with expansion screw is cemented over the microscrews and this in turn rests or leans on the palatal mucosa avoiding direct contact with the tooth crowns to prevent dentoalveolar inclinations and thus perform a purely bony expansion. Hyrax and Hass-type expansion screws were used and rapid palatal expansion was performed with two activations per day. This type of expansion may be orthopedic or surgically assisted. The technique is simple, inexpensive, accurate and with a high rate of effectiveness, but defi nitely requires knowledge of anatomy, physiology and of course mechanical basis for treatment success.

Key words: Skeletal transverse defi ciency, microscrews, Hyrax-type screw and Hass-type screw, disjunction of the suture.