DTIN0210

Clinical examples (2) Repositioning individual teeth The uprighting of molars The straightening of mesially tipped (2nd ) molars in a full denti- tion represents a therapeutic challenge. The treatment is fur- ther complicated if the tooth is not only tipped but also partly impacted.Thepresenceofanon- erupted third molar does not simplify the process (Fig. 1a). When planning the required appliance, it is important to con- sider whether it is necessary, for example, to reshape the entire dental arch (Figs. 1a–d) or just upright the tipped tooth. If miniscrews with bracket heads are used, it is possible to employ a special NiTi uprigh- ting spring (such as the Memory Titanol spring, FORESTADENT). A standard multi-bracket appli- ance can be used to reshape thedentalarch.Atthesametime, a second force element can be applied with the aid of a minis- crew and an uprighting spring (Figs. 1b–d). This avoids the loss of anchorage that inevitably occurs when only an uprighting spring is fixed to the multi- bracket appliance (Fig. 2). The straightening of an individual tooth may become necessary for periodontological, prosthetic or orthodontic reasons. This is a very simple procedure if a mini- screw and uprighting spring are used, and the appliance re- mains invisible to the observer. The tooth need only be fitted with an appropriate attachment system that makes it possible to fix this to the uprighting spring. Depending on how the spring is set, it is even possible to achieve intrusion/extrusion of the tooth. This form of treatment is inexp- ensive for the patient and the orthodontist will find it highly effective. Alignment of retinated teeth The alignment of retained or displaced teeth, particularly in the case of canines, is one of the most common forms of sur- gical intervention in the field of orthodontic techniques. Numer- ous appliances are available— rubber bands, springs, ortho- dontic chains—that are effective to a greater or lesser extent. All these mechanisms have the same underlying problem: the neighbouring teeth must be used—directly or indirectly—to provide an anchorage, so that the required traction forces can be applied. Ideally, the neigh- bouring teeth will offer the greater resistance so that only the retained tooth moves. Realis- tically, however, both compo- nents tend to move towards each other. In the worst-case scena- rio, only the group providing anchorage is displaced from its original position. This can occur if there is ankylosis of the reti- nated tooth, something that is difficult to evaluate during initial examination. If an attempt is made to move an ankylosed canine towards insufficient den- tal anchorage, the result will be the worst-case scenario. This can lead to an open bite in the region of the anterior teeth and premolars. Miniscrews provide the definitive form of anchorage for the alignment of displaced teeth (Figs. 3a–c). If sufficient space is available, brackets will not be needed in the initial phase of treatment. Skeletal adjustments Palatine suture expansion Rapid palatal expansion (RPE) is one of the most effective and DeNtaltribuNe|april-June, 2010 trends &applications 25 Fig. 2: The uprighting spring fixed to the main arch not only affects the molars, but also causes displacement of the premolars (loss of anchorage). (Photo: Prof. Dominguez, São Paulo, Brasil). Figs. 3a–c: The alignment of a displaced canine using a miniscrew. After the canines have been exposed, they are attached to a bracket by means of a miniscrew (a). After removal of the screw, the dental arch can be reshaped using a conventional technique (b, c). Figs. 4a–e: Obtaining additional transverse space by means of ‘hybrid RPE’. The initial diagnosis is an asymmetrical narrow jaw with insufficient space for tooth 13 (a). After fixture of the brackets, two miniscrews (OrthoEasy) were inserted during the same session (b). The hybrid RPE appliance was attached to the miniscrews and molar bands using laboratory abutments (FORESTADENT; c). The diastema shows the effect of the appliance after ten days’ use (d). Status after transverse expansion and concurrent reshaping of the dental arch (e). Fig. 5: The hybrid RPE appliance with adjuvant anterior hooks for the attachment of a Delaire mask. Figs. 1a–c: Figs. 1a–d: The uprighting of a second molar with simultaneous reshaping of the dental arch. The problem is clearly visible in the X-ray. The uprighting spring is fixed to a miniscrew (a, b). Status after five months without reactivation of the arch section (c, d). Miniscrews—a focal point in practice Six-part series by Dr Björn Ludwig, Dr Bettina Glasl, Dr Thomas Lietz, & Prof. Jörg A. Lisson—Part IV