DTIN0210

DeNtaltribuNe|april-June, 2010 trends &applications 27 correctional appliances—irre- spective of whether these use the Herbst splint or canted plane principle—have the same problem and the same undesir- able side effects. There is a risk of protrusion of the lower frontal teeth and/or distalisation of the upper molars. By means of passive stabilisation with the aid of two miniscrews (Figs. 7 and 8), these effects can be readily avoided. Orthognathic surgery After surgical intervention to relocate or reposition the jaw (for orthodontic or trauma- tological reasons), it is impor- tant to maintain a stable correla- tion between bone fragments and the jaw in the postoperative phase. This promotes healing and prevents relapse. The occlusion appliance is fixed intraorally, using intermaxi- lliary elastic or wire ligatures, depending on the situation. It is essential to use the appro- priate fixing options, whether this is a splint (Schuchardt splint) or a multi-bracket appli- ance. Where these are really only needed in one jaw or jaw section, the question arises of whether, in the era of the miniscrew, it is necessary to involve the other jaw in the stabilisation of the surgical effect. If miniscrews are used in the opposing jaw (Fig. 9), the same effect is achieved— but with considerably less restriction from the point of view of the patient. Pre-prosthetics It is the aim of pre-prosthetic orthodontics to position the teeth optimally for the subse- quent prosthesis. This can include intrusion, uprighting, and the opening or closing of gaps, amongst other tech- niques. As this series and many other publications have already shown, miniscrews are particu- larly useful in this context. Miniscrews can also be used as anchoring elements for a provisional prosthesis. Where teeth are missing (particularly the second canines, Fig. 10a) and the growth phase is not yet completed, the fitting of an intermediate prosthesis is problematic. As an alterna- tive, particularly where addi- tional anchorage is required, miniscrews can be used. A longer screw (8 or 10 mm) can be inserted in the centre of the dental ridge (Fig. 10b). There should be at least 1 mm of bone to the mesial and distal sides of the mini- screw. The hole for the insertion of a miniscrew (1.6 mm) should thus be at least 2.6 mm. A provi- sional crown can then be mounted onto the head of the miniscrew. If necessary, a bracket can be fixed to this crown (Fig. 10c). Outlook The clinical use of miniscrews supports a wide range of tasks. Dental repositioning that was previously deemed impossible becomes achievable, whilst possible repositioning tech- niques are improved and sup- ported. In order to achieve this, miniscrews alone are not sufficient; an appropriate range of equipment is also necessary. Several suppliers of mini- screws offer, in addition to screws and insertion tools, a number of devices that facili- tate the use of miniscrews. The fifth part of this series will focus on the wide range of useful auxiliaries that are available. Editorial Note: The next edition of Dental Tribune India will feature part V of this article. DT Dr. Björn Ludwig Am Bahnhof 54 56841 Traben-Trarbach, Germany Tel.: +49 65 41 81 83 81 Fax: +49 65 41 81 83 94 E-mail: bludwig@ kieferorthopaedie-mosel.de About the author