الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
The theory that a bracket system might influence treatment duration has been introduced, but it remains unsubstantiated by prospective evidence. However, the possible development of such an improvement would be of obvious value to both patient and clinician by reducing time commitments and limiting associated biologic risks.
In recent years, self-ligating brackets in particular the Damon system have attracted much attention and their use has increased considerably. Many advantages have been claimed, including reduced friction, reduction of generated forces and moments, less discomfort, more efficient tooth movement and sliding mechanics, greater arch expansion, constant arch-wire engagement, less chair side time, and reduced biostability. Although commercial and scientific interest has followed bracket developments, a lack of clinical evidence exists.
This study aimed at investigating bracket type-associated differences in terms of time needed for initial relief of irregularity and appointment numbers: conventional and passive self-ligating brackets.
Fifty Patients who met the inclusion criteria and consented to participate in the study were enrolled. The patients visiting the outpatient clinic of the Orthodontic Department, Faculty of Dentistry, Ain Shams University. They were randomly allocated to group A or group B. group A: 25 patients underwent fixed appliance therapy using conventional brackets and group B: 25 patients underwent fixed appliance therapy using passive self-ligating brackets.
Our study found no reduction in time needed for initial irregularity relieve using Damon self-ligating brackets when compared with conventional brackets, Time needed was shorter in Damon group (5.04 ± 1.30) than in conventional bracket group (5.05 ± 1.20) , however the difference was statistically insignificant (P=0.99).
Moreover our study found the difference in the number of visits between Damon self-ligating brackets when compared with conventional brackets was not statistically significant between both groups (P=0.86).
The main factor in this study that influenced the rate of alignment was the amount of initial irregularity, correlation between initial little irregularity index and rate of improvement revealed significant positive correlation between them in both groups. The rate of improvement was (0.96 ± 0.09) with little irregularity index 4 and increased to (1.17 ± 0.24) with little irregularity index 8.
Another factor in this study affected the rate of teeth alignment was the timing, as higher rates of improvement in the initial treatment months with deceleration of improvement rates as the months progress. The improvement percentage was 53% in first month which decreased to 0.3% in the seventh month in both groups.
We concluded that the claimed clinical performance and superiority of self-ligating brackets was not substantiated in this study as results demonstrate that bracket type selection has a negligible influence on initial irregularity relief .There was no statistically significant difference in the time required to correct mandibular crowding between passive self-ligating brackets and conventional brackets.
Cu NiTi wires appear to be the key elements in crowding relief rather than the type of bracket. Moreover, there was no significant difference in the comparison between both bracket types regarding the number of visits.
The factors in this study that influenced the rate of alignment was the amount of initial irregularity and the timing; as higher improvement rates were observed in the earlier months of treatment. Due to the paucity of randomized controlled studies addressing the aforementioned factors, further trials and meta-analyses will be required in order to reaffirm the credibility of the results from this study.
CONCLUSION
1. The claimed clinical performance and superiority of self-ligating brackets was not substantiated in this study as results demonstrate that bracket type selection has a negligible influence on initial irregularity relief. There was no statistically significant difference in the time required to correct mandibular crowding between passive self-ligating brackets and conventional brackets.
2. Moreover, there was no significant difference in the comparison between both bracket types regarding the number of visits.
3. The factors in this study that influenced the rate of alignment were the amount of initial irregularity and the timing; as higher improvement rates were observed in the earlier months of treatment.
4. Due to the paucity of randomized controlled studies addressing the aforementioned factors, further trials and meta-analyses will be required in order to reaffirm the credibility of the results from this study.