An investigation into the effects of Light Emitting Diode (LED) mediated photobiomodulation on root resorption and the rate of orthodontic tooth movement

Application of a constant 150g orthodontic force will be applied to the first premolar teeth for a period of 4 weeks (using orthodontic fixed braces) which are, and are not also exposed to daily Light Emitting Diode light of 850nm wavelength using an FDA approved device for this purpose (OrthoPulse - Biolux Research [Vancouver Canada]). This force will be applied to the first premolar on BOTH sides of the mouth, the only difference between the sides will be that one is exposed to daily 10minute exposures of light from the device in a single 10 minute application, which is self administered by the patient each day using the easy-to-use device (OrthoPulse). These devices are modified by the manufacturer to "sham" or "deactivate" one side of the light emitting diodes so as to only expose a single side to light. The patient and investigator will be unaware of which side is deactivated. An instructional video and personal 1 to 1 instruction on how to do use the device will be given to the patient at the commencement of the trial by the investigator who is a second year specialist orthodontic resident. Adherence will be monitored using a smartphone app which tracks device usage by downloading usage data from each participant's individual device. After 4 weeks of constant 150g of orthodontic force and daily usage of the device throughout, the first premolar teeth will be extracted simultaneously by the same investigator, under Local Anaesthesia (these extractions are a necessary part of the patients treatment) and examined under a Micro-CT (computer tomography) scanner to investigate root resorption changes on the root surfaces and determine whether there are any differences between the left side extracted tooth, and the right side tooth. After the above extractions are carried out, the space left behind will be closed orthodontically (using braces) by moving the adjacent teeth (canine and second premolar) toward each other until completely closed (approximately 8 weeks). During this orthodontic space closure phase, the patient will again use the device once per day, every day, for the entire 8 weeks. This is to investigate whether the application of light has any positive or negative effect on the rate of tooth movement. The rate of movement will be measured both clinically with digital calipers, and also by taking periodic impressions/moulds of the patients teeth (every 2 weeks - 5 impressions in total) and measuring the distance each tooth has moved throughout time. This data will be recorded for both the left and right sides, and compared.