Low-Level Laser Therapy: A Noninvasive Method of Relieving Postactivation Orthodontic Pain-A Randomized Controlled Clinical Trial.

INTRODUCTION: Pain is an unavoidable squeal of orthodontic treatment and it is known to decrease patient compliance and eventually affects treatment results. Numerous methods are available in literature to manage orthodontic pain after activation but they have their own limitations. This has led to exploring further options for management of pain. AIM: The aim of this study was to evaluate the effectiveness of low-level laser therapy (LLLT) in alleviating orthodontic pain after activation. MATERIALS AND METHODS: 20 subjects were randomly divided into an experimental and a control group. Each participant was given a retraction force of 200 gm/cm2/side. Subjects in the experimental group were exposed to low-level laser light at 980 nm and those in the control group were exposed to red LED light as placebo. The pain perceived after 0 hour, 1 hour, 3 hours, 48 hours, and 1 week of activation was recorded by patient using Visual Analog Scale. Statistical analysis was done using Mann-Whitney test. RESULTS: Results of the study showed that pain experienced by the subjects after orthodontic activation was higher in experimental group at T0 than in placebo group. At T1, T2, T4, and T5, the pain experienced by the subjects was less in the experimental group compared to the placebo group. Pain experienced by the subjects in the experimental group at T3 was significantly less as compared to those in the placebo group. CONCLUSION: A single dose of LLLT at 980nm, 2.5 W/cm2, and 600 J is effective in relieving orthodontic pain after activation.

Force Decay Characteristics of commonly used Elastomeric Chains on Exposure to various Mouth Rinses with different Alcohol Concentration: An in vitro Study.

AIM: The aim of this study was to test the effect of varying alcohol concentrations of various commercially available mouth-washes on force decay of elastomeric chains in prestretched and unstretched condition. MATERIALS AND METHODS: A total of five specimen groups were tested with a total sample size of 180 specimens. A specimen is described as a three-link, short module, clear elastomeric chain (3M Unitek, Ortho Plus, Ortho Organizer). The control and test groups were independently submerged in separate 37°C artificial saliva to simulate the oral conditions. Effects of different solution groups and time (initial, 1, 7, 14, 21, and 28 days) on three different elastomeric chains and force (cN) are analyzed with two-way analysis of variance; pair-wise comparisons are done by t-test. RESULTS: Higher mean force was recorded initially followed by 24 hours >7 days >14 days >21 days and 28 days respectively. The difference in mean force decay among the different time intervals was found to be statistically significant (p < 0.001). Among the different solutions, higher mean force was recorded in 21.6% alcohol mixture > Listerine 8.38% > Wokadine > alcohol mixture 8.38% > artificial saliva. CONCLUSION: In conclusion, alcohol-containing mouth rinses cause an increase in force decay of elastomeric chain over time. CLINICAL SIGNIFICANCE: These mouth rinses are commonly recommended during orthodontic treatment. The orthodontist can know better that the alcohol content of the mouth rinses and the structural and molecular modification results in the decay of elastomeric chain.

An in vitro Evaluation of Friction Characteristics of Conventional Stainless Steel and Self-ligating Stainless Steel Brackets with different Dimensions of Archwires in Various Bracket-archwire Combination.

AIM: The purpose of this research is to compare the frictional attributes of stainless steel conventional brackets and self-ligating stainless steel brackets with different dimensions of archwires. MATERIALS AND METHODS: The test was carried with two sets of maxillary brackets: (1) Conventional stainless steel (Victory Series), (2) stainless steel self-ligating (SmartClip) without first premolar brackets. Stainless steel, nickel-titanium (NiTi), and beta-Ti which are the types of orthodontic wire alloys were tested in this study. To monitor the frictional force, a universal testing machine (Instron 33R 4467) that comprises 10 kg tension load cell was assigned on a range of 1 kg and determined from 0 to 2 kg, which allows moving of an archwire along the brackets. One-way analysis of variance was used to test the difference between groups. To analyze the statistical difference between the two groups, Student's t-test was used. RESULTS: For Victory Series in static friction, p-value was 0.946 and for kinetic friction it was 0.944; at the same time for SmartClip, the p value for static and kinetic frictional resistance was 0.497 and 0.518 respectively. Hence, there was no statistically significant difference between the NiTi and stainless steel archwires. CONCLUSION: It is concluded that when compared with conventional brackets with stainless steel ligatures, self-ligating brackets can produce significantly less friction during sliding. Beta-Ti archwires expressed high amount of frictional resistance and the stainless steel archwires comprise low frictional resistance among all the archwire materials. CLINICAL SIGNIFICANCE: In orthodontics, frictional resistance has always had a major role. Its ability to impair tooth movement leads to the need for higher forces to move the teeth and it extends the treatment time which results in loss of posterior anchorage. Friction in orthodontics is related with sliding mechanics when a wire is moving through one or a series of bracket slots.