Effect of Low-Level Laser Therapy on Stability During Retention Phase.

The biggest problem in the orthodontic process is the pain and the long duration of treatment, which is also generally divided into 2 phases, namely the orthodontic tooth movement (OTM) and the retention phase. In recent decades, low-level-laser therapy has gained attention because it is non-invasive, inexpensive, relieves pain and has no significant adverse effects. Low-level-laser therapy (LLLT) has been proved to effectively induce and accelerate the remodeling process of alveolar bone by increasing the number of osteoblasts and osteoclasts. Therefore, LLLT is widely used in OTM to accelerate tooth displacement, but there are few studies and limited evidence on the stability whether it can strengthen and shorten the retention stage to avoid relapse. Thus, the purpose of this study is to investigate the stability after orthodontic treatment by observing the substantial influence of low-level-laser as during retention phase.Research Question(s)1. Does the low-level laser treatment can enhance stability and shorten retention time after orthodontic treatment or not will be demonstrated through 3 aspects：The Incisor Irregularities Index between laser and control group after application of LLLT at debond (0), 6 and 12 months of retentionThe interarch dimension: intercanine width, intermolar width, interpremolar width, arch length between laser and control group after application of LLLT at debond (0), 6 and 12 months of retentionThe overjet and overbite between laser and control group after application of LLLT at debond (0), 6 and 12 months of retentionObjectiveGeneral:The goal of this study is to investigate the stability in retention phase after application of LLLT during leveling and alignment with fixed appliances.Specific:To compare the Incisor Irregularities Index between laser and control group after application of LLLT at debond (0), 6 and 12 months of retentionTo compare the interarch dimension: intercanine width, intermolar width, interpremolar width, arch length between laser and control group after application of LLLT at debond (0), 6 and 12 months of retention To compare the overjet and overbite between laser and control group after application of LLLT at debond (0), 6 and 12 months of retention

Inclusion Criteria:1.Patient treated with laser and non-laser application during orthodontic treatment as in previous study2.The patient presents with mild to moderate crowding malocclusion with extraction of all 1st premolars and using conventional brackets3.The treatment of fixed appliances involving both arches4. Patients wearing vacuum formed retainers.5. Patients are compliance towards retainer wear with no history of retainer lost6. All permanent teeth erupted except for third molars.Exclusion Criteria:1.Age less than 18 years old2.Active caries and Periodontal disease3.Use any long-term use of analgesics or drugs that affect the function of the central nervous system.4. Non-compliance patients in term of wearing retainersWithdrawal criteria:1.Any patient who would like to withdraw from the experiment can do without their treatment being compromised.2.Patients who do not comply with the retainer requirements during the retention phase will be considered an automatic withdrawal from the research and their data will not be accepted.