Effects of orthodontic tooth movement on dental pulp condition

Orthodontic and dentofacial orthopaedic treatment is very common. Almost half of the children in developed world require a form orthodontic treatment during growth and development, which includes movements of teeth and jaws into correct positions with possible dental pulp involvement. Orthodontic tooth movement can endanger the vitality of the dental pulp. Loss of dental pulp vitality leads to pulp necrosis. Infection of the necrotic dental pulp could result in local complications such as odontogenic infections, formation of odontogenic cysts and resorption of dental and surrounding hard tissues and eventual tooth loss. The complications of dental pulp necrosis can cause long-term disability and loss of life quality and can be a significant burden for the national healthcare system. Studies into the effects of orthodontic tooth movement on dental pulp exhibit conflicting results. Because of ethical considerations and difficult execution most of the studies on human subjects didn’t include control group or control measurements; therefore, their quality of evidence was low, with high risk of bias. Furthermore, more quality evidence is required demanding in-depth research. The proposed study will the first clinical trial to comprehensively evaluate several indicators of pulpal vitality using repeatable state-of-the-art means on a large number of patients. Research goals are: ·        To measure the parameters of dental pulp vitality before, during and after active orthodontic tooth movement ·        To compare and correlate parameters of dental pulp between golden standard of clinical dental pulp sensitivity test (electro vitality and cold tests) and state of art diagnostic tools for pulp vitality (dental pulp oxygenation assessment via pulse oximetry, blood flow assessment via Laser-Doppler Flowmetry) ·        Dental pulp tissue status assessment using Magnetic resonance imaging (MRI) which is a state–of–the-art sensitive and non-invasive imaging method, which allows imaging of soft dental and periodontal tissues state unlike the any other available methods (x-ray, CT scan, ultrasound). ·        To measure and compare the effects of different types of active orthodontic tooth movement on the vitality of the dental pulp in its relation to the selected orthodontic risk factors  Research project proposal is based on the association between clinical and basic medical research science in the area of dental pulp physiology of men. Participants in pubertal growth period will be included in a prospective clinical research. The included participants will have orthodontic treatment plan of active orthodontic space closure in the lateral (transcanine) part of the lower dental arch using a preadjusted fixed orthodontic appliance. Active orthodontic forces will be used in a controlled manner to treat extraction spaces (because of severe dental crowding), tooth agenesis or extractions/tooth loss due to other of clinical conditions Covariates, which might influence pulpal reactions to orthodontic tooth movement such as speed of movement, length of residual space, type of tooth and force used will be controlled. Dental pulp will be monitored before, during and after the orthodontic treatment using conventional and contemporary means. To monitor the dental pulp sensitivity, vitality tests, Laser Doppler flowmetry and MRI scan of the will be used. MRI scan will be performed on a clinical 3T whole-body MRI system (TX Achieva, Philips, Netherlands) with a maximal gradient strength of 80 mT/m and with the use of a 32-channel receive head coil. Multi-spin echo (MSE) method will be used to obtain a series of T2 weighted sequences. T2 weighted images will be employed for T2 calculations of T2 relaxation time. MRI slices, which will optimally show the dental pulp contents of the teeth next to the residual space will be chosen.