Dental Tribune India Issue

trends &applications Dentaltribune|July-September, 201024 Therapeutic auxiliary elements Down in the jungle The number of dental suppliers worldwide that offer miniscrews has expanded to an estimated 45 and this number is still growing. Two trends are appar- ent from the range of products that are currently available. There are companies that supply miniscrews only in combination with the required insertion inst- ruments. However, miniscrews are only a means to an end where bone anchorage is concerned— an aspect that is far too often overlooked. This is because if the desired therapeutic outcome is to be achieved, appropriate auxiliary devices must also be used (eg springs, elastic chains, wires). For the purpose of a treat- ment, this means that a range of suppliers must be approached in Miniscrews—a focal point in practice Six-part series by Dr Björn Ludwig, Dr Bettina Glasl, Dr Thomas Lietz & Prof Jörg A. Lisson—Part V Figs. 3a–c: When a wire is to be bent at right angles in the screw slot (a), the edges at the point of crossover must be removed. This convenient detail is currently only found in the FORESTADENT OrthoEasy (b) and the tomaspin from DENTAURUM (c). Fig. 1: The wire ligature is appropriately activated and applies the required force for repositioning of the canine. (Photo: Dr Morea,Brazil) Fig. 2: The use of a square profile wire makes it possible to achieve very rigid (indirect) attachment. (Photo: Dr Böhm, Germany) order to obtain all the elements required for the actual proce- dure. A potential problem under these circumstances is that the miniscrews and the auxiliary elements may be incompatible. Very few suppliers of miniscrews also offer a complete system. Such a system consists of diag- nostic and therapeutic auxiliary products, in addition to minis- crews (Table 1). In the case of acompletesystem,itcanbeassu- med that the head of the mini- screw will be compatible with the auxiliary element. The build- ing-block principle can be used to construct an individually tailored appliance from the various elements. The greater the range of auxiliary elements that is available, the more freedom and flexibility these elements afford in a range of applications. Suppliersofminiscrewswho- se core business is the ortho- dontic sector usually also offer the necessary auxiliary products in their ranges. It is both con- venient and time-saving for the user when the appropriate prod- ucts are offered together or are available in sets. Auxiliary elements for direct chairside use These auxiliary elements can be divided into three main groups: • basic elements; • semi-finished elements; and • finished elements. Classification is determined by the extent to which the user has to process or manipulate the element before it can be used. Basic elements These consist solely of orthodon- tic wires (particularly wires with square profiles but also those with round profiles) of various grades and materials. The wires are used to fashion individual auxiliary elements, which can be more or less time-consuming depending on the type of appli- ance required. The wires (parti- cularly those made of stainless steel) are quite reasonably pri- ced. Round profile wires are mainly used as ligatures, in other words,simplyasfixingelements, but if appropriately twisted, they can also be used for traction purposes (Fig. 1). Three-dimen- sional monitoring of round pro- file wires is not possible as they offer little resistance to torque. Square profile wires, however, can be subjected to 3-D inspec- tion because they are torsion free & highly stable & provide (dependingontheirdimensions) for a very rigid attachment between miniscrew and appli- ance (Fig. 2). It is advisable to use a grade of wire that fills the slot of the miniscrew. In some cases, it may be nec- essary to bend a square profile wire. This can be advantageous in mesialisation when a hook can be provided on the pin for attaching a spring or elastic chain and for attachment to the main arch of the appliance. For this purpose, the wire should be bent at a right angle. Bent wires can also be used in another situation. A ligature or a drop of adhesive is used to fix a square profile wire in a miniscrew slot. Depending on the reciprocal forces and the quality of fixa- tion, the wire (square or round profile) can start to slip within the slot. This can readily be pre- vented by bending the wire, at least if a pin with a cross-slot is used (Fig. 3a). In these two situations, however, a grade of wire that fills the slot can only be used if the edges of the slot at the point of cross-over are removed. Of the 16 mini-screws with cross- slot bracket heads currently available, this convenient detail is only found in OrthoEasy (FORE-STADENT; Fig. 3b) and the tomas-pin (DENTAURUM; Fig. 3c). Semi-finished elements These auxiliary elements are generally components that are supplied in a functional form but must be adapted to individual requirements(Table2).Depend- ing on the type and material of the product, prices are in the moderate range and the time required for preparation is mini- mal. One example is the upright- ing spring (Fig. 4a), which can be used after only a few adjust- ments. Depending on how the spring is set, lower molars can be straightened and concomi- tantly intruded or extruded. This auxiliary product is particularly useful in pre-prosthetic proce- dures in which teeth need to be moved to provide an optimal baseline (Fig. 4b). Crimpable tubes to which square profile wire has been welded (Figs. 5a & b) can be used to attach minis- crews to a pre-existing MB (multi- bracket) appliance. If a fixed anchorage becomes necessary during treatment, this can be easily implemented using these wire elements without needing to remove the appliance or parts of it. During En Masse Retrac- tion, crimpable tubes with atta- ched wire can be used to fashion individual hooks (Fig. 6). These can thus be used to ensure that the traction force (provided by spring or elastic chain) is applied near the centre of resistance. There are three companies that offer pre-prepared wire elements, such as the L and U wires (FORESTADENT) and the tomas T wire (DENTAURUM). These elements facilitate the attachment of bands & brackets (Fig. 7a). The tomas T wire (Fig. 7b) with its three arms provides Companies supplying auxiliaries Name of the miniscrew DENTAURUM (Germany) tomas®-pin FORESTADENT (Germany) OrthoEasy® Mondeal (Germany) BENEFIT HDC (Italy) Spider Pin Micerium (Italy) M.A.S. Bio Materiales (Korea) Orthodontic Mini Implant Dentos (Korea) AbsoAnchor Jeil Medical (Korea) Dual-TopTM Anchor Screw Bio-Ray (Taiwan) A-1 IMTEC Corp. (USA) Ortho Implant Ormco (USA) VectorTASTM Table 1: There are at least 45 companies that manufacture or supply miniscrews. How- ever, only 11 of these offer auxiliary elements for use in orthodontic treatments that are compatible with their own screws.