***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: INTRODUCTION Self-ligating orthodontic brackets rely on clips , rather than ligatures , to hold the archwire in place . It is unknown whether replacing ligatures with clips affects the adherence of Streptococcus mutans . The aim of this research was to evaluate whether self-ligating brackets have an advantage over conventional brackets as determined by the adherence of S mutans . METHODS The sample consisted of 50 esthetic brackets , divided into 3 experimental groups and 2 control groups of 10 brackets each . Two experimental groups were active self-ligating brackets ( QuicKlear ; Forestadent , Pforzheim , Germany ; and In-Ovation C ; Dentsply GAC , Bohemia , NY ) ; the other was a passive self-ligating bracket ( Damon 3 ; Ormco , Glendora , Calif ) . The 2 control groups were conventional brackets ( Mystique ; Dentsply GAC ; and Clarity ; 3 M Unitek , Monrovia , Calif ) . The brackets were r and omly bonded to the canines , first and second premolars , and first and second molars in the m and ibular left hemiarch of 10 male participants . Biofilm was collected from the tooth surfaces before bonding and from the brackets on day 21 and placed in Petri dishes containing Mitis salivarius agar . The brackets were removed on day 28 and examined by using scanning electron microscopy . Statistical analysis , analysis of variance , and the Tukey correction with a P value of 0.05 were used . RESULTS The greatest numbers of colonies were found in an active self-ligating bracket group ( In-Ovation C ) , and the fewest colonies were in a conventional bracket group ( Clarity ) . The largest colonies formed on active self-ligating brackets . In the slot , the greatest formation was in a control group ( Mystique ) . CONCLUSIONS Self-ligating esthetic brackets do not promote greater or lesser S mutans colonization when compared with conventional brackets . Differences were found to be related to the material composition of the bracket INTRODUCTION Enamel decalcification is a common problem in orthodontics . The objectives of this r and omized clinical study were to enumerate and compare plaque bacteria surrounding 2 bracket types , self-ligating ( SL ) vs elastomeric ligating ( E ) , and to determine whether adenosine triphosphate (ATP)-driven bioluminescence could be used for rapid assessment of bacterial load in plaque . METHODS Patients ( ages , 11 - 17 years ) were bonded with SL and E brackets  in 14 maxillary and 12 m and ibular arches by using a split-mouth design . Recall visits were at 1 and 5 weeks after bonding . Plaque specimens were assayed for oral bacteria and subjected to ATP-driven bioluminescence determinations with a luciferin-based assay . RESULTS In most patients , teeth bonded with SL attachments had fewer bacteria in plaque than did teeth bonded with E brackets . At 1 and 5 weeks after bonding , the means for SL vs E brackets were statistically lower for total bacteria and oral streptococci ( P < 0.05 ) . ATP bioluminescence values were statistically correlated to the total oral bacteria and oral streptococci , with correlation coefficients of 0.895 and 0.843 , respectively . CONCLUSIONS SL appliances promote reduced retention of oral bacteria , and ATP bioluminescence might be a useful tool in the rapid quantification of bacterial load and the assessment of oral hygiene during orthodontic treatment OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity Abstract . Aim : The purpose of the present study was to investigate the composition and to assess the microhardness and structure of asreceived , retrieved , and recycled stainless steel brackets . Material s and Methods : New , used , and recycled br and - , slot size- , and prescription-matched appliances were subjected to scanning electron microscopy ( SEM ) , energy dispersive ( EDS ) electron probe micro analysis , metallographic analysis , and Vickers microhardness testing . Elemental analysis was performed on r and omly selected bulk material base and wing areas . Basic metal content and microhardness results were statistically analyzed using a two-way ANOVA and the Tukey test , with treatment ( asreceived , retrieved , and recycled ) and bracket region ( base , wing ) serving as discriminating variables ( α = 0.05 ) . Results : The results showed that there was no alteration in the bulk composition of the brackets among the three conditions . In contrast , differences were noted between bracket base and wing with respect to elemental composition among all groups , implying that the base and wings were manufactured from different alloys . The metallographic etching identified no difference in grain structure between the bracket base and wing components for all groups , regardless of treatment . Vickers microhardness demonstrated significant differences in hardness between base and wing for all groups and between recycled and retrieved states for the wing component . Zusammenfassung . Ziel : Das Ziel dieser Studie war die Untersuchung der Zusammensetzung und die Bestimmung der Mikrohärte und Struktur von fabrikneuen , gebrauchten und recycelten Stahlbrackets . Material und Method en : Neue , gebrauchte und recycelte Brackets , die von einem Hersteller stammten und in Slotgröße und Vorprogrammierung übereinstimmten , wurden der Rasterelektronenmikroskopie ( SEM ) , der energiedispersiven Röntgenmikroanalyse ( EDS ) , der metallographischen Analyse und dem Vickers-Mikrohärtetest unterzogen . Eine elementare Analyse wurde an zufällig ausgewählten Bracketbasen und -flügeln durchgeführt . Die Ergebnisse der elementaren metallischen Best and teile und der Mikrohärte wurden statistisch mithilfe einer zweifaktoriellen Varianzanalyse ( ANOVA ) und eines Tukey-Tests untersucht , wobei die Vorbeh and lung ( fabrikneu , gebraucht und recycelt ) und die  Bracketregion ( Basis , Flügel ) als diskriminierende Variablen dienten ( α = 0,05 ) . Ergebnisse : Die Ergebnisse zeigten , dass i m Bereich der Bracketbasen keine Veränderungen zwischen den drei Gruppen festzustellen waren . Es wurden hingegen Unterschiede zwischen Bracketbasis und -flügel hinsichtlich der elementaren Zusammensetzung in allen Gruppen beobachtet . Dies impliziert , dass Basen und Flügel aus verschiedenen Legierungen hergestellt wurden . Die metallographische Ätzung ergab bei allen Gruppen keinen Unterschied in der Kornstruktur der Bracketbasen und -flügel , ungeachtet ihrer Vorbeh and lung . Die  Mikrohärte  nach Vickers zeigte bei allen Gruppen signifikante Unterschiede bezüglich der Härte zwischen Basis und Flügel sowie zwischen recycelten und gebrauchten Flügelkomponenten 
    Output:
    
Friction force increased after intraoral aging in most of the studies .
However , there is lack of good quality evidence in this research area .
Conclusions Brackets present increased surface roughness after clinical use , and consequently increased coefficient of friction ( COF ) and Friction Force .