***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 In this prospect i ve clinical study , we assessed the relative speed of archwire changes , comparing self-ligating brackets with conventional elastomeric ligation methods , and further assessed this in relation to the stage of orthodontic treatment represented by different wire sizes and types . METHODS The time taken to remove and ligate  archwires for 131 consecutive patients treated with either self-ligating or conventional brackets  was prospect ively assessed . The study was carried out in the orthodontic department of a district general hospital in the United Kingdom . The main outcome measure was the time to remove or place elastomeric ligatures or open/close self-ligating brackets for 2 matched groups of fixed appliance patients : Damon2 self-ligating bracket ( SDS Ormco , Orange , Calif ) and a conventional mini-twin bracket ( Orthos , SDS Ormco ) . The relative effects of various wire sizes and material s on ligation times were investigated . The study was carried out by 1 operator experienced in the use of self-ligating and conventional brackets . RESULTS The Damon2 self-ligating system had a significantly shorter mean archwire ligation time for both placing ( P < .001 ) and removing ( P < .01 ) wires compared with the conventional elastomeric system .  Ligation of an archwire was approximately twice as quick with the self-ligating system . Opening a Damon slide was on average 1 second quicker per bracket than removing an elastic from the mini-twin brackets , and closing a slide was 2 seconds faster per bracket . This difference in ligation time between the Damon2 and the conventional mini-twin brackets became more marked for larger wire sizes used in later treatment stages . CONCLUSIONS The type of bracket and the size of wire used are statistically significant predictors for speed of ligation and chairside time . The self-ligating system offered quicker and arguably more efficient wire removal and placement for most orthodontic treatment stages 
    Output:
    
Major and Brauchli showed no significant differences in torque expression of active and passive SL brackets .
Conventionally ligated brackets presented with highest torque expression compared to SL brackets .
Minor difference was recorded in a torque expression of active and passive SL brackets .