JCO Interviews Dr. Thomas Weimert on Airway Obstruction in Orthodontic Practice
No one likes to remove orthodontic brackets in the middle of treatment, but that can be necessary if a patient needs magnetic resonance imaging (MRI). This Pearl describes the use of a single intraoral scan for both an Essix* temporary retainer to hold the teeth and an indirect rebonding transfer tray to replace the brackets in the same positions.
SERGIO HERNAN VALVERDE MONTALVA, DDS, MS
Associate Editor for Pearls
Indirect Rebonding Transfer Tray Following Magnetic Resonance Imaging
Stainless steel brackets and wires cause distortion and artifacts during an MRI of the head and neck, resulting in images of poor diagnostic quality.1 Therefore, any fixed appliances are usually removed prior to an MRI study.1
Debonding and rebonding of orthodontic brackets during active treatment is time-consuming.2 Moreover, if the initial bonding required a setup, or if the treatment phase involved finishing bends, the previous bracket positions must be precisely reproduced.
Further treatment delays can be avoided by delivering a temporary Essix retainer to be worn until the rebonding appointment. This Pearl demonstrates how a single intraoral scan can be utilized for both the Essix retainer and an indirect rebonding transfer tray. The retainer prevents tooth movements with nightly wear, and the transfer tray enables rebonding of the same brackets in unaltered positions.
Technique
The technique is illustrated on a 26-year-old female patient with agenesis of the lower central incisors (A). The treatment plan included extraction of the upper second premolars and lower deciduous incisors. Space closure was almost complete, but fixed appliances were still needed to manage anterior torque and to achieve a good posterior occlusion in conjunction with elastics. At this point, the patient was referred for an MRI of the head and neck area.
After the archwires were removed, an intraoral scan was performed using a scanning spray** (B), which is designed to avoid the inaccuracies that can be caused by reflections on metal, as well as to make the tooth surfaces more easily scannable (C).3
The comfortable Essix retainer preserved the tooth positions while the fixed appliances were off. Because the digital scan was most distorted in the area of the bracket hooks, the transfer tray was designed to be cut off at the level of the gingival bracket wings. After the bracket bases were sandblasted, the indirect rebonding was performed under dry-field conditions to obtain a perfect adhesion (F).
FOOTNOTES
- *Registered trademark of Dentsply Sirona Orthodontics Inc., Sarasota, FL; www.essix.com.
- **Trademark of VITA Powder Scan Spray, VITA Zahnfabrik, Bad Säckingen, Germany; www.vita-zahnfabrik.com.
- ***Trademark of Bay Materials LLC, Fremont, CA; www.zenduradental.com.
REFERENCES
- 1. Hasanin, M.; Kaplan, S.E.F.; Hohlen, B.; Lai, C.; Nagshabandi, R.; Zhu, X.; and Al-Jewair, T.: Effects of orthodontic appliances on the diagnostic capability of magnetic resonance imaging in the head and neck region: A systematic review, Int. Orthod. 17:403-414, 2019.
- 2. Poorsattar-Bejeh Mir, A. and Rahmati-Kamel, M.: Should the orthodontic brackets always be removed prior to magnetic resonance imaging (MRI)? J. Oral Biol. Craniofac. Res. 6:142-152, 2016.
- 3. Kang, S.J.; Kee, Y.J.; and Lee, K.C.: Effect of the presence of orthodontic brackets on intraoral scans, Angle Orthod. 91:98-104, 2021.
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DR. PAOLO ALBERTINI -
DR. ENRICO ALBERTINI -
DR. ZUCCHINI -
MR. GRANDI -
DR. LOMBARDO
Drs. Paolo Albertini and Zucchini are Research Fellows, Dr. Enrico Albertini is a Visiting Professor, and Dr. Lombardo is Professor and Chairman, Department of Orthodontics, University of Ferrara, Ferrara, Italy. Mr. Grandi is a Laboratory Technician, Bologna, Italy. Dr. Paolo Albertini is also in Private Practice, Via Livatino 9, 42124 Reggio Emilia, Italy. E-mail him at dr.paoloalbertini@gmail.com.
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