American Journal of Orthodontics and Dentofacial Orthopedics
Original articleAirborne particles produced during enamel cleanup after removal of orthodontic appliances☆
Section snippets
Material and methods
Six patients with full maxillary and mandibular fixed orthodontic appliances were seen over a period of 2 days (3 patients per day) for appliance removal and enamel cleanup. The orthodontic brackets were removed with debonding pliers, and the bands on the first permanent molars were removed with debanding pliers. In each case, the brackets had initially been bonded to the acid-etched enamel with Transbond XT (3M Unitek, Monrovia, Calif), a light-cured, filled, diacrylate bonding agent, and the
Results
The results of this initial analysis can only be considered semiquantitative. Scanning electron microscopic images are shown in Fig 1, Fig 2; EDX spectra of selected particles (marked O and X in Fig 2) are shown in Figure 3. EDX spectra of Transbond XT and Ketac-Cem are shown in Figure 4. The scanning electron microscopic images show that there is great variation in the size, shape, and composition of the particles produced during enamel cleanup. The observed particles ranged from 2 μm up
Discussion
From this study, it would seem that at the time of bracket and band removal, when a tungsten carbide bur in a slow-speed handpiece is used, a wide range of particle sizes can be produced. Importantly, some particles are in the PM2.5 category. Larger particles and some of those in the PM2.5 category will be deposited in the upper respiratory tract. Those deposited in the trachea, bronchi, and terminal bronchioles will be cleared within 1 to 2 days in a healthy person by the mucociliary action of
Conclusions
Under the conditions of this in vivo experiment, both PM10 and PM2.5 particles are produced during enamel cleanup after orthodontic fixed appliance therapy. These particles were consistent with the composition of the fillers and matrix of the diacrylate bonding agent and glass polyalkenoate band cement. Traces of enamel and, surprisingly, of the tungsten carbide bur were also found to be present. The significance of these findings to the health of the patient, operator, and staff is unknown and
Acknowledgements
The authors thank Professor Roy Richards and Dr Tim Jones (Cardiff University) for their assistance.
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Submitted, March 2003; revised and accepted, June 2003.