Original article
Airborne particles produced during enamel cleanup after removal of orthodontic appliances

https://doi.org/10.1016/S0889-5406(03)00623-1Get rights and content

Abstract

Airborne particles can be produced during enamel cleanup after the removal of fixed orthodontic appliances. Particles with an aerodynamic diameter of less than 2.5 μm, known as PM2.5, can reach the alveoli of the lungs. The aim of this experiment was to qualitatively determine whether such particles are produced during enamel cleanup at the end of orthodontic treatment. Particles were collected and examined under a scanning electron microscope. Aerodynamic diameters of the particles ranged from approximately 2 to 30 μm. X-ray analysis confirmed not only the presence of components of the adhesives being removed, but also tungsten from the bur and tooth enamel. In conclusion, inhalable particles can be produced during enamel cleanup at the completion of orthodontic treatment. Further investigation is required to determine the clinical significance of such particles, how their production can be minimized, and whether even smaller, fine or ultrafine, particles are produced.

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.

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