Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2017-02-07, 08:52:43 | version 1.38.0
22 Ortho Tribune Asia Pacific Edition | 1+2/2017 ORTHO TRENDS Creative adjuncts for clear aligners to improve predictability By Dr S. Jay Bowman, US The concept of clear aligners has grown in leaps and bounds inter- nationally since the introduction of Invisalign (Align Technology) in 1999. In the 1940s, Dr Harold Kesling first proposed the original theoretical basis for moving teeth with a series of retainers, but it took more than 50 years before computer technology made the idea workable. Although some of the initial excitement attending the idea that all patients could be treated without metal fixed orthodontic appliances wore off quickly, early adopters and innovators have worked diligently to improve and enhance clear aligner methods. Limitations of clear aligner treat- ment simply required some time and experience to discover, but ultimately resulted in a series of articles quantifying issues often experienced clinically.1–16 As patients’ and practitioners’ desires for aesthetic alternatives to fixed appliances continued to coalesce in the past decade, there have been a number of techno- logical and biomechanical ad- vancements that have led to an ever-increasing number of treat- ment application possibilities for aligners, including the expansion to treating teenagers.17, 18 In those endeavours, a series of articles were published suggesting innovative treatment options with various ad- juncts to clear aligners,19–21 includ- ing Hu-Friedy’s Clear Collection instruments (Fig. 1).22–24 Clear Collection As understanding of some of the limitations of clear aligner applications came to light, altera- tions to biomechanics, materials and treatment planning were in- troduced. The primary aims were to improve the predictability of specific tooth movements and to expand the scope of treatment to a wider variety of presenting malocclusions. A set of instruments were cre- ated specifically for clear aligners in order to enhance, accent and increase the spectrum of appli- cability and acceptability of this form of aesthetic orthodontic treat- ment. The Clear Collection consists of four instruments designed to individualise aligners to address specific treatment needs.23–24 The Tear Drop The Tear Drop instrument is used to add a notch or hook in the gingival margin of aligner plastic for the application of typical or- thodontic elastics.19–21, 23 The design of this cut-out is in the shape of a teardrop with the intent that the reservoir of the notch will keep an elastic in place on the aligner (Figs. 2a–c). In this manner, the aligner with elastics can be inserted into the mouth, reducing the fumbling and difficulty associated with at- tempting to put elastics into slits or notches after the aligner tray is already on the teeth. The Tear Drop cuts can be made anywhere along the aligner tray edges where elas- tics may be needed, such as inter- maxillary Class II, Class III or delta, or Class I intra-maxillary applica- tions, even involving the use of mini-screw anchors to support the elastic forces (Fig. 3).19, 21, 23 The Hole Punch The Hole Punch instrument is used to create a half-moon cut-out Figs. 6a & b: Areas of gingival impingement or irritation from clear aligners can be cleared using the Hole Punch to remove plastic.—Figs. 7a & b: The Vertical instrument produces a shallow indent in the plastic to accent rotational couples on individual teeth.—Fig.8: The indents from either the Vertical or the Horizontal pliers may be formed immediately adjacent to attachments to accent the contact point of plastic in the right angle between composite and tooth, with the intention of increasing the effectiveness of the attachment.—Figs. 9a & b: Adding root torque to specific teeth is enhanced by creating indents with the Horizontal pliers. The same tool may also be used to increase the retention of aligners or clear retainers.—Fig.10: Aligner lag or loss of tracking is a common occurrence, especially for maxillary lateral incisors, the least predictable tooth movement. The air gap is a symptom of ill-fitting aligners and may have a number of causes (e.g. poor compliance, insufficient space created for the tooth to follow and lack of surface area contact with plastic). Fig. 1: The Hu-Friedy Clear Collection consists of four instruments: the Tear Drop, Hole Punch, Vertical and Horizontal.—Figs. 2a–c: The Tear Drop is designed to cut a teardrop-shaped notch in the margin of clear aligners to retain orthodontic elastics for various applications.—Fig.3: Class II clear aligner treatment enhanced with Class II inter-maxillary elastics and Class I intra-maxillary elastics attached to mini-screw anchors to produce the intended vectors of force.—Figs. 4a & b: The Hole Punch is used to cut a half-moon of plastic at the aligner margin to clear the way for bonded buttons or brackets in order to connect orthodontic elastics or elastomeric chains.—Fig.5: Seating elastics used to improve posterior intercuspation in finishing aligner treatment. The Hole Punch cleared plastic to permit bonding of buttons for the inter-maxillary box elastics. 1 2a 2b 2c 5 4b 4a 3 6a 6b 7a 7b 8 9a 9b 10