***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVE : Low-level laser therapy ( LLLT ) has been promoted for its beneficial effects on tissue healing and pain relief . However , according to the results of in vivo studies , the effectiveness of this modality varies . Our purpose was to assess the putative effects of LLLT on healing using an experimental wound model . DESIGN AND SETTING : We used a r and omized , triple-blind , placebo-controlled design with 2 within-subjects factors ( wound and time ) and 1 between-subjects factor ( group ) . Data were collected in the laboratory setting . SUBJECTS : Twenty-two healthy subjects ( age = 21 + /- 1 years , height = 175.6 + /- 9.8 cm , mass = 76.2 + /- 14.2 kg ) . MEASUREMENTS : Two st and ardized 1.27-cm(2 ) abrasions were induced on the anterior forearm . After wound cleaning , st and ardized digital photos were recorded . Each subject then received LLLT ( 8 J/cm(2 ) ; treatment time = 2 minutes , 5 seconds ; pulse rate = 700 Hz ) to 1 of the 2 r and omly chosen wounds from either a laser or a sham 46-diode cluster head . Subjects reported back to the laboratory on days 2 to 10 to be photographed and receive LLLT and on day 20 to be photographed . Data were analyzed for wound contraction ( area ) , color changes ( chromatic red ) , and luminance . RESULTS : A group x wound x time interaction was detected for area measurements . At days 6 , 8 , and 10 , follow-up testing revealed that the laser group had smaller wounds than the sham group for both the treated and the untreated wounds ( P < .05 ) . No group x wound x time differences were detected for chromatic red or luminance . CONCLUSIONS : The LLLT result ed in enhanced healing as measured by wound contraction . The untreated wounds in subjects treated with LLLT contracted more than the wounds in the sham group , so LLLT may produce an indirect healing effect on surrounding tissues . These data indicate that LLLT is an effective modality to facilitate wound contraction of partial-thickness wounds The split-mouth design is a popular design in oral health research . In the most common split-mouth study , each of two treatments are r and omly assigned to either the right or left halves of the dentition . The attractiveness of the design is that it removes a lot of inter-individual variability from the estimates of the treatment effect . However , already about 20 years ago the pitfalls of the design have been reported in the oral health literature . Yet , many clinicians are not aware of the potential problems with the split-mouth design . Further , it is our experience that most statisticians are not even aware of the existence of this design . Since most of the critical remarks appeared in the oral health literature , we argue that it is necessary to introduce the split-mouth design to a statistical audience , so that both clinicians and statisticians clearly underst and the advantages , limitations , statistical considerations , and implication s of its use in clinical trials and advise them on its use in practice OBJECTIVE The aim of this study was to investigate the effect of low-level laser therapy ( LLLT ) on reducing post-adjustment orthodontic pain  via evaluation of gingival crevicular fluid ( GCF ) composition changes at the level of prostagl and in-E(2 ) ( PGE(2 ) ) and visual analogue scale ( VAS ) . BACKGROUND DATA LLLT has been found to be effective in pain relief . PGE(2 ) has the greatest impact on the process of pain signals and can be detected in GCF in order to investigate the response of dental and periodontal tissues in a biochemical manner . MATERIAL S AND METHODS Nineteen patients ( 11 females and 8 males ; mean age 13.9 years ) were included in this study . Maxillary first molars were b and ed and then a r and omly selected first molar at one side was irradiated ( λ820 nm ; continuous wave ; output power : 50 mW ; focal spot : 0.0314 cm(2 ) ; exposure duration : 5 sec ; power density : 1.59 W/cm(2 ) ; energy dose : 0.25 J ; energy density : 7.96 J/cm(2 ) for each shot ) , while the molar at the other side was served as placebo control . The GCF was collected from the gingival crevice of each molar to evaluate PGE(2 ) levels , before b and placement , 1 and 24 h after laser irradiation . Pain intensity was analyzed at 5 min , 1 h , and 24 h after b and placement by using VAS . RESULTS Although no difference was found in pain perception at 5 min and 1 h , significant reduction was observed with laser treatment 24 h after application ( p<0.05 ) . The mean PGE(2 ) levels were significantly elevated in control group , whereas a gradual decrease occurred in laser group . The difference in PGE(2 ) levels at both 1 and 24 h were statistically significant between two groups ( p<0.05 ) . CONCLUSIONS The significant reductions in both pain intensity and PGE(2 ) levels revealed that LLLT was efficient in reducing orthodontic post-adjustment pain INTRODUCTION Pain control during orthodontics is an important aspect of patient compliance . The aim of this prospect i ve , r and omized , double-blind clinical trial was to compare the pain control effectiveness of acetaminophen ( 650 mg ) with ibuprofen ( 400 mg ) taken 1 hour before separator placement in adolescents . METHODS The patients recorded their discomfort on a 100-mm visual analog scale during several activities ( teeth not touching , chewing , and fitting back teeth together ) and by selecting words adapted from the McGill Pain Question naire at 5 time intervals : immediately before separator placement , immediately after separator placement , 2 to 3 hours later , at bedtime , and on awakening the next morning . The patients ( n = 33 ) were r and omly assigned to the ibuprofen group or the acetaminophen group . A repeated- measures ANOVA was performed as a function of time and treatment group . RESULTS Pain increased immediately after separator placement , lessened , and then increased to a peak the next morning . The most commonly selected words to describe pain were " annoying , " " sore , " and " tight . " There was no significant difference in pain at any time after separator placement regardless of the medication taken . CONCLUSIONS Acetaminophen and ibuprofen produced no significant differences in pain after separator placement patients undergoing any form of dental treatment , to the extent that 77 % of a patient population reported some degree of pain from a visit to the dentist.1 Pain following orthodontic adjustments appears to be equally prevalent.2 - 10 Jones and Chan showed that compliance with orthodontic treatment may be predicated on the amount of initial pain and discomfort experienced.5 Other studies indicate that plaque control may suffer as a result of the pain associated with orthodontics.7,11 Although analgesics have been found to reduce such discomfort , in most cases they do not totally eliminate it.12 - 15 Moreover , some patients may be allergic to these agents , and one report suggested that nonsteroidal anti-inflammatory drugs may adversely affect the rate of tooth movement.14 Patients who do not respond to or elect not to use pharmacological therapy have had few practical alternatives . Some orthodontists recommend chewing on gum or a plastic wafer immediately after adjustments.16 Proffit suggested that lower force levels could reduce pain,17 but Lim and colleagues showed that pain or discomfort was still experienced by most patients even when “ physiologic and light forces ” were used.18 Recently , there have been major developments in the underst and ing of pain mechanisms and of new approaches to the management of pain.19 Low-level laser therapy has been shown to produce analgesic effects in many clinical applications , including orthodontics.18 Transcutaneous electrical nerve stimulation ( TENS ) is another non-pharmacological , non-invasive method of reducing post-orthodontic adjustment pain.20,21 Vibratory stimulation , a classic noninvasive and non-medicinal method of reducing pain , could also be effective in orthodontic patients .21 - 26 The orthodontic application of this method was first investigated by Dr. Powers on a patient with a history of painful post-adjustment episodes during closure of a wide maxillary midline diastema with elastic chain . After placing a new elastic chain , Dr. Powers observed that gentle vibration of the maxillary central incisors produced two effects : the blanching of the tissue between and above the incisors was quickly reversed , and the previous level of pain did not occur OBJECTIVE To analyze the effect of low-level laser therapy ( LLLT ) on perception of pain after separator placement and compare it with perceptions of control and placebo groups using a frequent irradiation protocol . MATERIAL S AND METHODS Eighty-eight patients were r and omly allocated to a laser group , a light-emitting diode ( LED ) placebo group , or a control group . Elastomeric separators were placed on the first molars . In the laser and LED groups , first molars were irradiated for 30 seconds every 12 hours for 1 week using a portable device . Pain was marked on a visual analog scale at predetermined intervals . Repeated measure analysis of variance was performed for statistical analysis . RESULTS The pain scores of the laser group were significantly lower than those of the control group up to 1 day . The pain scores in the LED group were not significantly different from those of the laser group during the first 6 hours . After that point , the pain scores of the LED group were not significantly different from those of the control . CONCLUSIONS Frequent LLLT decreased the perception of pain to a nonsignificant level throughout the week after separator placement , compared with pain perception in the placebo and control groups . Therefore , LLLT might be an effective method of reducing orthodontic pain INTRODUCTION The purpose of this study was to clinical ly evaluate the effect of low-level laser therapy ( LLLT ) as a method of reducing pain reported by patients after placement of their first orthodontic archwires . METHODS The sample comprised 60 orthodontic patients ( ages , 12 - 18 years ; mean , 15.9 years ) . All patients had fixed orthodontic appliances placed in 1 dental arch ( maxillary or m and ibular ) , received the first archwire , and were then r and omly assigned to the experimental ( laser ) , placebo , or control group . This was a double-blind study . LLLT was started in the experimental group immediately after placement of the first archwire . Each tooth received a dose of 2.5 J per square centimeter on each side ( buccal and lingual ) . The placebo group had the laser probe positioned into the mouth at the same areas overlying the dental root and could hear a sound every 10 seconds . The control group had no laser intervention . All patients received a survey to be filled out at home describing their pain during the next 7 days . RESULTS The patients in the LLLT group had lower mean scores for oral pain and intensity of pain on the most painful day . Also , their pain ended sooner . LLLT did not affect the start of pain perception or alter the most painful day . There was no significant difference in pain symptomatology in the maxillary or m and ibular arches in an evaluated parameter . CONCLUSIONS Based on these findings , we concluded that LLLT efficiently controls pain caused by the first archwire OBJECTIVE To test the hypothesis that there is no difference in the pain associated with orthodontic force application after the application of local CO(2 ) laser irradiation to the teeth involved . MATERIAL S AND METHODS Separation modules were placed at the distal contacts of the maxillary first molars in 90 patients in this single-blinded study . In 60 of these patients ( 42 females and 18 males ; mean age = 19.22 years ) this was immediately followed by laser therapy . The other 30 patients ( 18 females and 12 males ; mean age = 18.8 years ) did not receive active laser irradiation . Patients were then instructed to rate their levels of pain on a visual analog scale over time , and the amount of tooth movement was analyzed . RESULTS Significant pain reductions were observed with laser treatment from immediately after insertion of separators through day 4 , but no differences from the nonirradiated control side were noted thereafter . No significant difference was noted in the amount of tooth movement between the irradiated and nonirradiated group . CONCLUSIONS The hypothesis was rejected . The results suggest that local CO(2 ) laser irradiation will reduce pain associated with orthodontic force application without interfering with the tooth movement The aim of this study was to evaluate the efficacy of diode superpulsed low-level laser therapy ( SLLLT ) in reducing  experimentally induced orthodontic pain . Overall , 120 subjects ( 23.01 ± 1.39 years ) were enrolled for a clinical trial . Subjects were r and omly assigned to upper ( U , N = 60 ) or lower ( L , N = 60 ) jaw groups . All subjects received 4 elastomeric separators mesial and distal to the upper ( U group ) or lower ( L group ) right first molar and bicuspids . Each subject of the U and L groups was r and omly assigned to laser ( Ul , N = 20 and Ll , N = 20 ) , placebo ( Up , N = 20 and Lp , N = 20 ) or control ( Uc , N = 20 and Lc , N = 20 ) sub-groups . Subjects in laser groups received a single GaAs diode SLLLT application ( 910 nm , 160 mW , beam diameter of 8 mm , applied for 340 s ) immediately after placing orthodontic separators . Placebo groups received a simulated SLLLT and controls did not receive any ther 
    Output:
    
It was concluded that the use of diode LLLT for orthodontic pain appears promising .
However , due to method ological weaknesses , there was insufficient evidence to support or refute LLLT ’s effectiveness .