Editor’s Summary and Q&A



Editor's Summary and Q&A




American Journal of Orthodontics and Dentofacial Orthopedics, 2010-01-01, Volume 137, Issue 1, Pages 12-13, Copyright © 2010 American Association of Orthodontists


Introduction

Our aim was to compare the time required to complete the alignment of crowded maxillary anterior teeth (canine to canine) between Damon MX (Ormco, Glendora, Calif) and In-Ovation R (GAC, Central Islip, NY) self-ligating brackets.

Methods

Seventy patients from the first author's office were included in this randomized controlled trial by using the following inclusion criteria: nonextraction treatment on both arches, eruption of all maxillary teeth, no spaces in the maxillary arch, no high canines, maxillary irregularity index greater than 4 mm, and no therapeutic intervention planned involving intermaxillary or other intraoral or extraoral appliances including elastics, maxillary expansion appliances, or headgear. The patients were randomized into 2 groups: the first received a Damon MX bracket; the second was bonded with an In-Ovation R appliance, both with a 0.022-in slot. The amount of crowding of the maxillary anterior dentition was assessed by using the irregularity index. The number of days required to completely alleviate the maxillary anterior crowding in the 2 groups was investigated with statistical methods for survival analysis, and alignment rate ratios for appliance type and crowding level were calculated with the Cox proportional hazard regression. An analysis of each protocol was performed.

Results

No difference in crowding alleviation was found between the 2 bracket systems. Higher irregularity index values were associated with the increased probability of delayed resolving of crowding.

Conclusions

The use of passive or active self-ligating brackets does not seem to affect treatment duration for alleviating initial crowding.


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Editor's Summary and Q&A Nikolaos Pandis , Argy Polychronopoulou and Theodore Eliades American Journal of Orthodontics and Dentofacial Orthopedics, 2010-01-01, Volume 137, Issue 1, Pages 12-13, Copyright © 2010 American Association of Orthodontists Introduction Our aim was to compare the time required to complete the alignment of crowded maxillary anterior teeth (canine to canine) between Damon MX (Ormco, Glendora, Calif) and In-Ovation R (GAC, Central Islip, NY) self-ligating brackets. Methods Seventy patients from the first author's office were included in this randomized controlled trial by using the following inclusion criteria: nonextraction treatment on both arches, eruption of all maxillary teeth, no spaces in the maxillary arch, no high canines, maxillary irregularity index greater than 4 mm, and no therapeutic intervention planned involving intermaxillary or other intraoral or extraoral appliances including elastics, maxillary expansion appliances, or headgear. The patients were randomized into 2 groups: the first received a Damon MX bracket; the second was bonded with an In-Ovation R appliance, both with a 0.022-in slot. The amount of crowding of the maxillary anterior dentition was assessed by using the irregularity index. The number of days required to completely alleviate the maxillary anterior crowding in the 2 groups was investigated with statistical methods for survival analysis, and alignment rate ratios for appliance type and crowding level were calculated with the Cox proportional hazard regression. An analysis of each protocol was performed. Results No difference in crowding alleviation was found between the 2 bracket systems. Higher irregularity index values were associated with the increased probability of delayed resolving of crowding. Conclusions The use of passive or active self-ligating brackets does not seem to affect treatment duration for alleviating initial crowding. Editor's summary In the last decade, several new appliance systems have been developed; among the more prominent are passive and active self-ligating brackets. For most of these appliances, evidence supporting their marketed characteristics is lacking. Thus far, most prospective and randomized clinical trials demonstrated no difference between conventional and self-ligating brackets for the rate of tooth movement. The purpose of this study was to compare the time required to complete the alignment of crowded maxillary anterior teeth (canine to canine) between passive and active self-ligating brackets. Seventy patients were included in this randomized controlled trial (RCT), with their selection based on the following criteria: nonextraction treatment plan, fully erupted dentition, no spacing in maxillary arch, no high canines, an irregularity index greater than 4 mm, no extraoral appliances or elastics, and no maxillary expansion appliances. The active self-ligating group was bonded with the Roth prescription In-Ovation R bracket, and the passive self-ligating group received the high-torque version of the Damon MX bracket. The amount of crowding was assessed with Little's irregularity index. Archwire sequence was the same for both treatment groups: 0.014-in Damon arch form copper-nickel-titanium followed by 0.016 × 0.025-in Damon archform copper-nickel-titanium. The 70 patients who met the inclusion criteria were randomized to receive either an active or a passive self-ligating appliance. The time for alignment of the maxillary 6 anterior teeth only for each patient was calculated in days. The conclusions of this RCT were consistent with the results of other studies and provide an additional piece of what is becoming a complex but useful picture. Active and passive self-ligating brackets did not show a difference in treatment duration for correcting maxillary anterior crowding, although the degree of crowding did. The type of movement and the ligation mechanism of self-ligating brackets does not seem to affect duration of treatment. Table I Demographic and clinical characteristics of sample Total (n = 70) mean or % SD Damon MX (n = 35) mean or % SD In-Ovation R (n = 35) mean or % SD P value ∗ Demographic characteristics Age (y) 13.8 1.8 13.8 1.8 13.8 1.7 NS Sex (%) Girls 58.6 60.0 57.0 NS Boys 41.4 40.0 43.0 Clinical characteristics Crowding (irregularity index, mm) 7.5 2.1 8.0 2.1 7.0 2.0 NS Angle class (%) I 48.6 51.4 45.7 NS II 47.1 42.9 51.4 III 4.3 5.7 2.9 NS, Not significant. ∗ P value for comparison of group means by t test or differences in proportions by chi-square test and Fisher exact test. Table II Treatment time to alignment by wire system and crowding severity Total Mean time to alignment (d) Minimum (d) Median (d) Maximum (d) P value ∗ Wire system Damon MX 33 107.1 56 99 175 NS In-Ovation R 33 95.0 54 92 161 Total 66 101.0 54 95.5 175 NS, Not significant. ∗ P value based on the log-rank test for equality of survivor functions. Q & A Turpin: What was the most difficult aspect of this study to manage? Eliades: The first author, who handled all patient flow and associated treatment and logistics, had to deal with precise data collection and diligent follow-up of the patients in treatment. This task required dedication and meticulous recording of treatment sequences and details to ensure the reliability of the analysis. Turpin: As a researcher, is it more rewarding to conduct an in-vivo RCT than a lab-bench type of study with no patient involvement? Eliades: Laboratory investigations are far easier to handle compared with clinical trials, particularly RCTs. In-vitro studies offer the option of examining various effects on properties of appliances and materials as well as identifying the mechanisms underlying these effects. Nonetheless, the actual clinical performance of materials and techniques cannot be assessed in vitro because of several issues pertinent to the simulation of clinical conditions and the intraoral environment. Therefore, retrieval analyses and RCTs are the state-of-the-art methods of research for material alterations in vivo and clinical efficiencies, respectively. Turpin: Recognizing signs of enthusiasm with this type of study design, what is your next study likely to examine? Eliades: We are completing an RCT on the retention of the treatment outcome and relapse with various appliances and techniques. This follows up previous articles on the topic and will complete the picture of the multi-faceted influence of various ligation types on efficiency, bond strength, periodontal condition, root resorption, dental changes, and force levels with self-ligation brackets. Read the full text online at: www.ajodo.org , pages 12.e1-12.e6.

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