The Implant Distal Jet.

M olar distalization for the treatment of Class II malocclusions has historically depended on patient compliance with intra-and extraoral auxiliaries. 1-5 In recent years, " non-compliance " devices such as the Distal Jet,* 6,7 Jones Jig,* 8 Pendulum,** 9 and repelling magnets 10 have been developed. The problem of anchorage loss during molar distaliza-tion with these appliances has not been solved, however , by using Nance palatal buttons or premolar anchorage arms. Bussick and McNamara found that the Pendulum produced an average 10.6° of distal molar tipping, and that the upper first premolars or deciduous first molars moved 1.8mm anteriorly, were extruded 1mm, and tipped 1.5° mesially. 11 Ghosh and Nanda noted 2.6mm of upper first pre-molar mesial movement and 1.7mm of extrusion. 12 Bolla and colleagues reported anchorage loss of 16-43% with the Pendulum, 26-55% with the Jones Jig, and 15-62% with the Distal Jet. 13 On average, the movement produced by the most common intraoral distalizing appliances was 71% molar distalization and 29% reciprocal anchorage loss. 13 Ngantung and colleagues confirmed that the anchorage support of the standard Distal Jet cannot completely resist the mesial reciprocal forces of molar distalization. 14 This article introduces an Implant Distal Jet (IDJ) that uses miniscrews to reduce or eliminate the loss of anchorage in Class II treatment. Appliance Design The IDJ is made with bilateral tubes embedded in a modified Nance acrylic palatal button, which is attached through supporting wires to the first premolars. If bilateral distalization is not needed , a unilateral tube can be used. A 240g nickel titanium open-coil spring is placed on each tube to generate a distal force against the first molars. 6,7 Skeletal anchorage is obtained by inserting Miniscrew Anchorage System*** (MAS) titanium miniscrews (Fig. 1) in the palatal interradicular