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Dental Tribune Asia Pacific Edition No. 1+2, 2017

at the gingival margin of aligner plastic (Figs. 4a & b).19–21, 23 The in- tention is to relieve the plastic to permit the application of bonded buttons or brackets on specific teeth to support orthodontic elas- tics or chains. These cuts can be placed wherever needed along the aligners on either buccal or lingual surfaces.Acommonscenariowould be punching holes in the buccal margin of plastic at the maxillary and mandibular first molars and canines to bond buttons to sup- port seating or box elastics (Fig. 5)23 or cutting a half-moon on both the lingual surface of the maxillary first molar and buccal surface of the mandibular first molar to facil- itate the use of a through-the-bite cross-bite elastic. In addition, the Hole Punch may be employed to simply clear plastic away from impinging gin- gival tissue anywhere along the aligners.23 The incisive papilla is a common location for this type of irritation that can be quickly resolved by clipping the plastic in that area for each tray in a series (Figs. 6a & b). Individualising aligners with accent pliers Two accent pliers round out the Clear Collection. These unique instruments were designed to enhance specific types of tooth movement by increasing plastic contact points in precise locations for individual teeth. The intent is to increase the predictability of tooth movements by creating shallow indents in the plastic to augment prescribed mechanical couples. Most importantly, these pliers are not heated. In addition, these indents may be produced to increasetheretentivenessofalign- ers or clear retainers in undercuts and at line angles. The Vertical Controlled rotations of teeth are often difficult to achieve with aligners,20, 25–27 as the computer- generated prescribed movement may not be translated accurately to the tooth. The first of the two ac- cent pliers is called the Vertical20, 24 and it is used to gently impress a vertical indent into the aligners in a specific location in the lingual and/or facial plastic for an individ- ual tooth (Figs. 7a & b). Rotating maxillary lateral incisors and ca- nines are often sites of these types of problems.20, 25–27 As an example, the rotated lateral incisors in Class II Division 2 malocclusions are dif- ficult to correct and typically require that overcorrection be designed into the aligners at the outset. If additional rotation is indicated, an indent can be placed in the plastic at the mesial line angle on the facial surface and the distal line angle on the lingual surface to create some extra force in the form of a rotational couple in a series of aligners.24 This may preclude the necessity of another round of refinement appliances to achieve the intended goal. If a composite attachment is in place on a specific tooth, the Vertical can be used at the right-angle contact of the aligner and the composite to sharpen the contact point in that location for more efficient transmission of force to the tooth (Fig. 8). The Horizontal The second accent instrument is the Horizontal19–21, 24 and it is pri- marily used to produce an indent to affect a change in tooth root ro- tation or torque.18, 24, 28, 29 A horizon- tal impression into the plastic at the gingival margin of the aligners will emphasise the force applied to torque the roots of individual teeth (Fig. 9a). These horizontal indents can also be placed at the right-angle junction of a compos- ite attachment and the tooth to enhance the contact, thereby in- creasing the effectiveness of the intended tooth movement and re- ducing the risk of lag as the plastic may slip away. Another option is to place horizontal indents at the marginal undercuts of the crown of the teeth to increase the reten- tiveness of aligners or retainers (Fig. 9b). Common applications: Beating aligner lag and bootstrap mechanics Besides facilitating the typical addition of inter-maxillary elas- tics for a variety of anchorage supports for tooth movement or intention to alter dentoalveolar compensation (i.e. Class II, Class III, resolving deep and open bites, ex- traction space closure, etc.19–24, 30–34 ), a common application for the Tear Drop and the Hole Punch is estab- lishing bootstrap mechanics.20, 23 For instance, a tooth or teeth may be lagging behind the prescribed movement, especially in terms of extrusion—the tooth may not be following along the projected path (Fig. 10). This may be due to in- adequate space created adjacent to each side of the tooth or lack of adequate contact on the tooth or attachment. Initially, Chewies Aligner Tray Seaters20, 23, 35 (another of our crea- tions from our private practice; DENTSPLY Raintree Essix) are rou- tinely used at each new aligner to assist in seating them on to the teeth (Fig. 11a), along with instruc- tions to massage the trays into place (use fingers to push the trays on to the teeth as though attempt- ing to stretch them over attach- ments and undercuts for the first few days). Despite those efforts, an air gap between the incisal edge of the teeth and the plastic may develop (Fig. 11b). It may be that inadequate space has been created prior to extrusion and the inter- proximal contacts thus cannot pass by each other (consider the widening taper towards the ante- rior incisal edges) and aligner lag or lack of tracking is the result. In these instances or in antici- pation thereof, a bootstrap set-up is prepared.20, 23 This consists of placing bonded buttons on the lingual surface of the offending tooth near the gingival margin by creating clearance for the button in the aligner plastic with the Hole Punch (Figs. 12a & b). On the facial surface of the same tooth there are two options: another button and a hole punch (Fig. 12c). The Tear Drop is used to create two elastic notches at the mesial and distal gingival embrasure spaces (Fig. 12d). A small-diameter orthodontic elas- tic is then applied to either the teardrop notches or the button on the facial surface of the tooth and stretched over the occlusal surface of the aligner to the lingual but- ton. In this scenario, the elastic is intended to more predictably ex- trude the tooth into the aligner to the prescribed position. Future view on aligners As demand by patients for more comfortable, hygienic and aesthetic treatments increases, the clear aligner market will re- spond with more advances and al- ternatives. In addition, orthodon- tists will learn to better push the envelope of applications by adding adjuncts to improve the effective- ness and ultimately the predicta- bility of treatments with aligners. Much like fixed appliances, the ability to individualise, accent and enhance clear aligner biomechan- ics reduces the known limitations of aligners and the associated clin- ical frustrations of the orthodon- tist. Managing alterations of series of aligner trays in real time (in- cluding the use of a Clear Collection prescription form;24 Fig. 13) pro- vides increased flexibility in the endeavour towards increased pre- dictability of aligner orthodontic outcomes. More details on the Clear Collection, treatment applications, downloadable publications (in- cluding the Clear Collection pre- scription form) and a series of instructional videos can be found on the Hu-Friedy website. 23 Ortho Tribune Asia Pacific Edition | 1+2/2017 ORTHO TRENDS International Expo nd 22 www.dentalsouthchina.com Area C of China Import and Export Fair Complex Organizer: Guangdong Int’l Science & Technology Exhibition Company Exhibitor Service Tel: 0086-20-83549150 Email: dental@ste.cn Visitor Service Tel: 0086-20-83561589 Email: dentalvisit@ste.cn Fax: 0086-20-83549078 Guangzhou Top Dental Show in China 行业盛事博览牙科 nd th March 2 -5 ,2017 AD Figs. 11a & b: Chewies Aligner Tray Seaters were developed as a kind of mini-tooth positioner for patients to clench in specific sites to encourage trays to seat and reduce the development of aligner lag.—Figs. 12a–d: Bootstrap mechanics are designed to extrude individual teeth into clear aligners with orthodontic elastics. (a & b) The Hole Punch is used to cut out a half-moon clearance for a bonded button on the lingual surface of a selected tooth. (c) The Tear Drop is used to place two elastic notches in the facial margin of the aligner at both the mesial and distal gingival embrasures. An elastic is then stretched from the dual notches, over the aligner, to the lingual button to generate an extrusive force. (d) A second option is to cut a second half-moon in the facial surface, bond a labial button and place the elastic from the labial to lingual surfaces over the aligner.—Fig.13: A Clear Collection prescription form is completed for each patient to indicate the instruments that will be required to customise each aligner in a series, along with the specific sites where they will be employed on each tooth. DrS.JayBowman is a diplomate of the Ameri- can Board of Orthodontics and a member of the Edward H.AngleSociety of Orthodontists. At the Association of Orthodontists (Singapore) Congress, he will be presenting a lecture titled “Creative adjuncts for clear aligners: Improving the predictability of aligner treatments”, among others. He main- tains a private specialty orthodontic practice in Portage in Michigan in the US. He can be contacted at info@ kalamazooorthodontics.com. 11a 11b 12d 12c 12b 12a 13

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