Background and Objectives: Low-intensity laser therapy (LILT) has been studied in many fields of dentistry, but to our knowledge, this is the first time that its effects on orthodontic movement velocity inhumansare investigated.
Study Design/Patients and Methods: Eleven patients were recruited for this 2-month study. One half of the upper arcade was considered control group (CG) and received mechanical activation of the canine teeth every 30 days.
The opposite half received the same mechanical activation and was also irradiated with a diode laser emitting light at 780 nm, during 10 seconds at 20 mW, 5 J/cm2, on 4 days of each month. Data of the biometrical progress of both groups were statistically compared.
Results: All patients showed significant higher acceleration of the retraction of canines on the side treated with LILT when compared to the control.
Conclusions: Our findings suggest that LILT does accelerate human teeth movement and could therefore considerably shorten the whole treatment duration. Lasers Surg. Med. 35:117–120, 2004. 2004 Wiley-Liss, Inc.
Key words: diode laser; orthodontic tooth movement; bone remodeling; canine retraction
Orthodontic treatment has its importance based on esthetic and functional rehabilitation of the masticatory system. Because it is the result of orthodontic forces promoting the remodeling of alveolar bone tissue, the movement should be as slight as possible, in order to prevent collateral effects such as bone necrosis or root resorption.
From the patients’ point of view, accelerating the teeth movement is desirable, because the treatment duration, frequently months or even years, is considered very long. Literature shows some methods to stimulate bone remodeling such as drug injections , electric stimulation , and ultrasound application . These methods depend on injections, that could be associated to discomfort and pain, or a sophisticated apparatus that demands applications for a long term to achieve its therapeutic effects. Lowintensity laser therapy (LILT) is simple to perform and uses inexpensive equipments that can be utilized for several different treatments in the clinical practice of orthodontics such as in reduction of post adjustment pain  or in the treatment of traumatic ulcers promoted by the appliance in the oral mucosa . Some reports have suggested that LILT is able to accelerate teeth movement in animals by increased midpalatal suture expansion in rats with formation of better quality bone  and augmented production of differentiated osteoclasts . Given the problems in extrapolating results and parameters from animal research to human practice, trials in humans are essential. To the best of our knowledge, effects of biomodulation promoted by LILT to acceleratehumanteeth movement have never been reported.
The aim of this innovative study was to analyze the effects of 780-nm diode laser irradiation on human canines’ retraction during an orthodontic movement with a healthy tissular response, by the measurement of the biometrical progress. A higher retraction velocity could decrease treatment time and therefore treatment costs.
PATIENTS AND METHODS
Eleven Caucasian patients of both genders, with age ranging from 12 to 18 years, were attended at a private office. They all had a clinical indication for extracting both first maxillary (upper) premolars, because there was not enough space for a complete alignment or presence of biprotrusion. For each patient, this diagnosis was based on a standard orthodontic documentation with photographs, model cast, cephalometric, panorama, and superior premolar periapical radiographies. The following criteria were observed for selection of the patients: they should appear to have an adequate nutrition, with no signals of systemic illnesses and the patient should not be under medical treatment that could interfere in the orthodontic movement like ingestion of analgesics, anti-inflammatory medicine, or antibiotics.
The patients and each legal responsible were informed about the risks and benefits of the procedures performed and they consented to participate in this study.