***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 Our aim was to prospect ively assess in-vivo color alterations of natural teeth associated with fixed orthodontic treatment . METHODS Twenty-six consecutive patients were treated with fixed appliances bonded with a chemically cured or a light-cured resin  with a split-mouth design . The spectrophotometric data of a st and ardized labial circular area of all teeth were recorded , before bracket bonding and after debonding and cleaning procedures . The color parameters of the Commission Internationale de l'Eclairage-L∗ , a∗ , and b∗ ( lightness , red/green , and blue/yellow)-were measured for each adhesive and type of tooth , and the corresponding color differences ( ΔE ) between the interval groups were calculated . The effect of these parameters on color was assessed with 3-way mixed analysis of variance ( ANOVA ) and the Bonferroni comparisons test ( α < 0.05 ) . RESULTS Orthodontic treatment was associated with changes in color parameters . The L∗ values decreased ( P < 0.001 ) , whereas the a∗ and b∗ values increased ( P < 0.001 ) at the end of treatment . All measured types of teeth demonstrated significant color changes ( ΔE ) ; their mean differences ranged from 2.12 to 3.61 ΔE units . Chemically cured resin was associated with greater color changes than light-cured composite . CONCLUSIONS The color of natural teeth is changed in various ways after fixed orthodontic treatment The purpose of this study was to examine the effects of ultrasonic orthodontic bracket removal and cleanup and compare them with conventional debonding and cleaning of the enamel surfaces with burs and polishing disks . The amount of enamel loss and time for bracket removal and clean-up were also addressed . Thirty extracted human premolars were collected . The teeth were r and omly placed in one of the three debonding groups : debonding with orthodontic pliers and enamel clean-up with finishing burs and polishing disks ( group 1 ) , debonding with orthodontic pliers and ultrasonic clean-up of the enamel surface ( group 2 ) , and ultrasonic debonding enamel clean-up ( group 3 ) . The teeth were stored for 48 hours in 100 % humidity before bracket removal . All brackets were then removed . Polyvinyl siloxane impressions were made before and after bracket removal . Direct measurements of the teeth in micrometers were made at all steps . An additional 30 teeth were similarly prepared , and the brackets were debonded and cleaned-up as in the three groups previously described . The total time for bracket removal and enamel clean-up for each group was recorded in seconds . ( ABSTRACT TRUNCATED AT 250 WORDS The purpose of this study was to evaluate enamel colour alteration of five different orthodontic bonding adhesives by means of digital measurements after exposure to photoageing in order to simulate discolouration of adhesives in vivo . Seventy-five non-carious premolars were r and omly divided into five equal groups . The brackets were bonded with five different adhesives ( Transbond XT , Eagle Bond , Light Bond , Blugloo , Unite ) and subjected to artificial accelerated photoageing for 24 hours . The enamel surfaces were colourimetrically evaluated before bonding , following debonding and cleaning with a tungsten carbide bur , after polishing with Stainbuster , and after photoageing of the debonded enamel surface . The Commission Internationale de l'Eclairage(CIE ) colour parameters ( L*a*b * ) were recorded and colour differences ( DeltaE ) were calculated . The results were statistically analyzed using the Kruskall-Wallis test . Further investigation among subgroups was performed using Dunn 's multiple correlation test ( P < 0.05 ) . The clinical detection threshold for DeltaE value was set at 3.7 units . DeltaE values between the first and second measurements showed an increase in the Transbond XT , Eagle Bond , and Light Bond groups . The highest DeltaE value was 1.51 + /- 1.15 in the Transbond XT group . No clinical ly significant DeltaE value was observed . Colour changes of orthodontic bonding systems induced by photoageing can not be clinical ly observed . Polishing with Stainbuster eliminates enamel surface roughness , which may improve light reflection 
    Output:
    
The studies review ed suggested that orthodontic treatment alters the original color of enamel , and both adhesive systems and resin-removal methods can contribute to this change .
Conclusion There is no strong evidence from this review that orthodontic treatment with fixed appliances alters the original color of enamel .