MH cortical screws, a revolutionary orthodontic TADs design

MH cortical screws were designed to combine the advantages of thick mini-implants with the versatility of micro-screws while avoiding the disadvantages of both.

An MH cortical screw (MH is an abbreviation for the author's name) was made from titanium material. The screw has a 3 mm-long amphora-shaped shank of 2 mm thickness at its thinnest and 3 mm at its thickest part. Uniform 4 mm diameter threads blend into a 1 mm cutting tip. An external hexagonal head with side retentive ligature holes and a central hole for attachments was fabricated on a saucer-shaped gingival collar. Multiple attachments have been prepared for amending to the central hole.

The shank design allowed cortical plate retention. The uniform threads and the amphora design provided maximum primary and secondary stability, respectively. The self-drilling tip allowed for a flapless technique, while the hexagonal head with side holes facilitated screwdriver control and allows for ligature wire anchorage. Cleats and buttons facilitated the use of elastics and springs, together with bracket-heads and eyelets for titanium molybdenum alloy and nickel-titanium wires inclusion. Adjustable hooks and chains provided versatility of line of action. Cover screws to retain extra-tissue mini-plates applied skeletal anchorage and long-term retention with flapless manipulations.

MH cortical screws are a novel and important introduction to orthodontic anchorage. They combine primary and secondary stability with avoidance of root damage together with insertions into attached gingiva only. Multiple and versatile attachments allow for the application of biomechanical techniques according to the clinician's preferences. Extra-tissue mini-plates facilitate maximum anchorage for skeletal control and long-term retention without surgery.