Effectiveness of Different Sterilization Methods on Clinical Orthodontic Materials

Background Orthodontic appliances such as wires and brackets received from manufacturers come unsterilized and may be contaminated with various microorganisms before being used in the mouth. In this study, we evaluated and identified the bacterial contamination on orthodontic appliances along with the disinfecting efficacy of ultraviolet (UV) light and various sterilization methods. Methods Different orthodontic appliances were obtained from manufacturers divided into 5 sterilization methods and a control group (control, UV, dry heat and steam autoclave, ethyl alcohol, and 2% glutaraldehyde). Microbiological and DNA sequencing was performed on the appliances to identify the contaminated bacteria. Results Bacterial contamination identified on the orthodontic appliances were Staphylococcus aureus, Staphylococcus epidermidis, Lactobacilli, Klebsiella pneumoniae, Bacillus licheniformis, and Bacillus cereus. UV sterilization method effectively prevented the bacterial growth when compared to the control (unsterilized) orthodontic appliances. Conclusion We concluded that the orthodontic appliances received from the manufacturer showed bacterial contamination. All of the tested sterilization methods including UV light were effective in eliminating the bacterial contamination on the orthodontic appliances. Since UV light does not cause change in material properties and is cost effective with relative ease of use, its use in clinical practice for the disinfection of orthodontic appliances is suggested before placement in the mouth.