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Table of Contents   
ORIGINAL ARTICLE  
Year : 2022  |  Volume : 33  |  Issue : 1  |  Page : 52-57
Comparative evaluation of duration of extraction space closure and degree of root resorption with conventional and self-Ligation brackets


1 Dental Officer, Department of Orthodontics and Dentofacial Orthopedics, Government Dental Center, Nagaland, India
2 Department of Orthodontics and Dentofacial Orthopedics, Mansarovar Dental College, Bhopal, India
3 Department of Orthodontics and Dentofacial Orthopedics, ESIC Dental College and Hospital, Rohini, New Delhi, India
4 Department of Orthodontics and Dentofacial Orthopedics, Bharati Vidyapeeth (Deemed to be University) Dental College and Hospital, Navi Mumbai, Maharashtra, India

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Date of Submission03-Dec-2021
Date of Decision21-Apr-2022
Date of Acceptance25-Apr-2022
Date of Web Publication09-Aug-2022
 

   Abstract 


Introduction: Determination of difference between conventional and passive self-ligating brackets (SLBs) in respect of extraction space closure, patient perception and root resorption. Material and Methods: Eighty patients were divided into four groups of 20 each with age-sex-matched control using a simple randomisation technique and allocation concealment with a closed opaque envelope method. Group 1 consisted of conventional brackets with Connecticut New Archwire (CNA) wire mushroom loop, group 2 consisted of conventional brackets with TAD (AbsoAnchor, Korea) supported retraction, group 3 consisted of passive SLB with CNA archwires (Libral Traders, India) mushroom loop and group 4 consisted of passive SLB brackets with TAD (AbsoAnchor, Korea) supported retraction. The rate of retraction, root resorption and patient satisfaction were assessed. All conventional brackets (Orthox, USA) and passive SLBs (CaptainOrtho, India) had 0.018 Roth prescriptions with a slot size of 0.018 × 0.025. Results: Retraction was the fastest in group 2 with a mean of 1.266 ± 0.14 mm/4 week and a duration of 23.40 weeks. Similarly, group 4 showed the most sluggish movement with a mean of 1.182 ± 0.80 mm/4 weeks with a total duration of 25 weeks; howeverdifferencesce among groups were not statistically significant (P = 0.470). Conclusion: SLBs have advantage of better patient comfort, less pain and reduced chairside time. Though the present study found increased treatment duration with SLB along with friction mechanics, refuting the previous claims of reduced friction with SLBs, however, the difference was not statistically significant and results have to be extrapolated with caution and experience considering other advantages of SLBs.

Keywords: CNA mushroom loop, passive self-ligating brackets (PSBs), root resorption, TAD

How to cite this article:
Maurya RK, Bhardwaj P, Singh H, Mishra HA. Comparative evaluation of duration of extraction space closure and degree of root resorption with conventional and self-Ligation brackets. Indian J Dent Res 2022;33:52-7

How to cite this URL:
Maurya RK, Bhardwaj P, Singh H, Mishra HA. Comparative evaluation of duration of extraction space closure and degree of root resorption with conventional and self-Ligation brackets. Indian J Dent Res [serial online] 2022 [cited 2022 Oct 4];33:52-7. Available from: https://www.ijdr.in/text.asp?2022/33/1/52/353526



   Introduction Top


Self-ligating brackets (SLBs) gained popularity in past few years with conflicting evidence of having reduced chairside time, low friction, better hygiene and comfort in comparison with conventional brackets. Miles and Fleming reported weak evidence supporting SLBs except for chairside time.[1],[2] Nieto reported lower friction with SLBs in comparison with conventional.[3] Turnbull and Birnie found that type of bracket and size of wire were strong predictors for speed of ligation and chairside time.[4] Whereas, Pandis and Scott and coworkers have not reported any significant difference in root resorption with conventional or SLBs.[5],[6] Aras et al.[7] have reported lesser root resorption with SLBs. The panoramic, intraoral periapical radiographs and cone-beam computed tomography (CBCT) have been used to assess the post orthodontic root resorption. Pandis et al.[5] and Scott et al.[6] reported importance of panoramic radiograph in localisation of root resorption with lesser radiation, availability and cost factors over CBCT.

The shortened treatment durations have been reported by using temporary anchorage devices (TADs).[8] Differential loop moments have also transformed its mechanics with improved metallurgy from stainless steel to titanium-based alloys.[9] Newer TMA-based archwires such as Connecticut New Archwire, CNA (Ortho Organizers Calif) have not only revolutionised frictionless biomechanics by using mushroom-shaped loops instead of conventional 'T' or 'keyhole loops' for achieving more predictable orthodontic treatment outcome but also reduced patients pain and post-operative root resorption.[9]

Accelerated orthodontic treatment using non-invasive modalities has been reported with varied success rates, however, the faster treatment is often associated with added side effects.[10],[11],[12],[13],[14] Present study proposed to accelerate orthodontic treatment by using advantages of SLBs/conventional brackets in various combinations with TAD and improved metallurgy in friction vis-a-vis frictionless retraction mechanics. Hence, null hypothesis was formulated that there would be no difference between conventional brackets and SLBs in respect of treatment duration, patient perception and root resorption either with friction or frictionless mechanics.


   Material and Method Top


The present study was conducted as a randomised controlled trial in tertiary care dental hospital after institutional ethical clearance vide certificate number 05/IEC/ADCRR/2017. The trial was registered with CTRI vide trial number CTRI/2019/02/017647. Eighty patients (48 male, 32 female) (mean age: 16.17 ± 4.8) matching inclusion and exclusion criteria were selected after informed and written consent. The article is being reported as per CONSORT-2010 extension.

Sample size calculation

The sample size of 80 patients was calculated based on an α value of 0.05 and a β of 0.2 to achieve 80% of power and variance of 0.9 and the effect size was considered moderate (0.5) as per Cohen coefficient for primary variable as the rate of space closure.[8]

Selection criteria

Inclusion criteria

  1. Angle's Class I type 2 or Class II div 1 requiring extraction of the first premolar
  2. Symmetrical upper and lower arches.


Exclusion criteria

  1. Syndromic or patients with deformity and asymmetry.
  2. Periodontally compromised dentition.


Sample Distribution [Figure 1]
Figure 1:(a) Group I (Conventional Bracket with CNA Loop) (b) Group II (Conventional Bracket with TADs adjunct) (c) Group III (SLBs with CNA Loop) (d) Group IV (SLBs with TADs adjunct)

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Eighty patients were divided into 20/group as described below.

Group 1: Conventional Roth metal bracket with CNA wire mushroom loop, Group 2 Conventional Roth metal brackets with TAD supported closed coil retraction springs, Group 3 Passive SLB with CNA wire mushroom loop and Group 4 Passive SLB brackets with TAD supported closed coil spring retraction springs.

The randomisation and treatment allocation

A stratified block randomisation was used to ensure that the samples for the four treatment techniques were well balanced for sex, angle class and starting age. After randomisation to treatment technique, each patient was randomly assigned to care by one member of a panel of four clinicians.[10] Treatment procedure was carried out by principal investigator. Study was carried out with 'Intention to treat' all patients.

Blinding

Blinding was done at randomisation and result assessment level using a team of experienced orthodontist who were not part of direct patient intervention for patient randomisation and data recording and analysis.

All essential diagnostic records consisting of plaster study models, digital models, photographs, lateral cephalogram and orthopantomograms (OPG) were obtained pre-treatment, pre-retraction and post retraction. Radiographs were taken with NEWTOM machine (Giano Italy). All plaster models were scanned for 3-D digital models using CeraMill and MindTM (Amann Girrbach, Austria) and standardised with 1:1 calibration.

The treatment plan for patients included extraction of maxillary or mandibular first premolars to allow for maximum retraction. All conventional brackets (Orthox, USA) and passive SLBs (CaptainOrtho, India) had 0.018 Roth prescriptions with a slot size of 0.018 × 0.025 inches. En-masse space closure was carried out with mushroom-shaped retraction loop fabricated in 0.017 × 0.025 inches CNA archwires (Ortho Organizers Calif) with 25–30-degree α and 35–40-degree β in group 1 and 3.[9] Posted 0.016 × 0.022 stainless steel (Libral Traders, India) wires with a mild curve of Spee, 9 mm NiTi closed coil spring (Forestadent, Germany) and 1.4 × 8 mm mini-implant (AbsoAnchor, Korea) were used in their respective groups between the maxillary second premolars and first molar.

The space closure was quantified using digital Vernier caliper (AEROSPACE, China) to 0.1 mm from mesial bracket of canine to distal surface of molar tube at T1 (before starting of retraction) and T2 (after completion of space closure) intraorally and reconfirmed on plaster and digital models. The rate of retraction was calculated in 'mm/4' as follows: ([T1-T2]/number of weeks to close entire space) × 4. The closure of space was also differentially expressed by quantifying the amount of movement in molars and incisors against a stable reference plane in vertical and horizontal planes [Figure 2]. OPG at T1 and T2 was used to assess root resorption using the index described by Levander and Malmgren.[12] All the measurements were done by two independent orthodontists who were blinded to the treatment mechanics.
Figure 2: Measurement of (a) extraction space closure, (b) Anchorage loss and (c) Root resorption

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Patient's pain perception and satisfaction were assessed using visual analogue score (VAS) rating scale of 1 to 10 through 'Pain rating scale software', where 1 was considered to be 'no pain' and 10 as 'intolerable pain'. All patients were instructed to record their pain response after each visit as VAS1 (on following evening of loop or coil spring activation), VAS2 (3rd day of appointment of loop or coil activation) and VAS3 (28th day of appointment of loop or coil activation).

Statistical analysis

Data was analysed with Statistical Package for the Social Sciences (SPSS) version 21(IBM Inc, USA). Kolmogorov–Smirnov tests showed normal distribution of data. Thirty percent of randomly selected measurements were repeated to rule out inter- and intra-observer variability after 3 weeks of initial measurement (intra-class correlation coefficient = 0.88 to 0.91). Inter-observer variability was calculated according to Dahlberg's formula. The repeated measurements of space closure and root resorption were tested for the Kappa coefficient of agreement. The descriptive statistics of mean differences, standard deviations and standard errors were calculated for all variables. One-way analysis of variance (ANOVA) was used for comparison of groups. Inter-group difference was assessed by Tukey's HSD post hoc test. Root resorption grading was assessed using Kruskal–Wallis test. Tests of significance were two-tailed, and the minimum level of significance was set at P < 0.05 [Table 1].
Table 1: Descriptive Statistics of Samples, Variables and Outcomes

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   Results Top


The rate of retraction was the fastest in group 2 with a mean rate of 1.266 ± 0.14 millimetre (mm)/4 weeks and duration of 23.40 weeks. Similarly, group 4 showed the most sluggish movement with a mean rate of 1.182 ± 0.80 mm/4 weeks with a total duration of 25 weeks, however, difference among groups was not statistically significant. (P = 0.470) [Table 1] and [Table 2].
Table 2: Level of significance of rate of retraction, root resorption and pain

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Upper central incisors showed significant difference at inter-group level in sagittal plane (P = 0.0000) with significant difference between group 1 and 2 (P = 0.012), group 1 and 3 (P = 0.00), group 1 and 4 (P = 0.00), group 2 and 3 (P = 0.00) and group 2 and 4 (P = 0.00). Lower central incisors also showed significant difference at inter-group level in sagittal plane (P = 0.0001) with significant difference between group 1 and 2 (P = 0.010), group 1 and 4 (P = 0.001) and group 3 and 4 (P = 0.010) [Table 3].
Table 3: Level of significance of inter and intra-group incisors and molar movement

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Upper central incisors showed significant difference at inter-group level in vertical plane (P = 0.0000) with significant difference between group 1 and 3 (P = 0.004), group 1 and 4 (P = 0.000), group 2 and 4 (P = 0.00), group 3 and 4 (P = 0.000). Lower central incisors also showed significant difference at inter-group level in vertical plane (P = 0.0000) with significant difference between group 1 and 2, group 1 and 3, group 1 and 4 (P = 0.000) and group 2 and 3 (P = 0.02) [Table 3].

Upper permanent first molars migrated mesial maximum in group 2 by 2.2 mm, and lowest in group 1 with 1.7 mm, revealed no significant difference in the sagittal plane (P = 0.0758). Lower molars showed significant differences among the groups with maximum mesial migration in group 1 and minimum in group 4 with significant difference between group 1 and 4 (P = 0.01) [Table 3].

Upper molars showed significant difference in vertical plane at inter-group level with significant difference between group 1 and 2 (P = 0.0019), group 1 and 3 (P = 0.00), group 2 and 3 (P = 0.00), group 2 and 4 (P = 0.03) and group 3 and 4 (P = 0.000). Lower molars also showed a significant difference in vertical plane at inter-group level with a significant difference between group 1 and 2, group 1 and 3, group 1 and 4, group 2 and 3, and group 3 and 4 (P = 0.00) [Table 3].

Post extraction space closure comparison of OPG revealed grade II level root resorption among all four groups. The Kruskal–Wallis test showed root resorption non-significant between groups (P < 0.864) [Table 2].

The pain perception at VAS1 revealed group 3 had a least painful experience with a mean VAS score of 4.4 ± 1.07, and group 2 had the most painful experience with a mean score of 5.5 ± 1.17. (P = 0.342) The pain perception at VAS2 score revealed group 3 had a least painful experience with a mean of 4.4 ± 1.07 and group 2 had a most painful experience with a mean score of 5.5 ± 1.17. (P = 0.09) The pain perception at VAS3 score revealed group 3 had a least painful experience with a mean score of 4.4 ± 1.07 and group 2 had the most painful experience with a mean score of 5.5 ± 1.17. Intergroup comparison did not reveal any statistically significant difference between groups (P = 0.053) [Table 2].


   Discussion Top


The present study compared conventional and SLBs with different combinations of space closure mechanics for reducing treatment duration, root resorption and better patient experience.

Randomisation was achieved by stratified block randomisation and treatment allocation using the sealed closed opaque envelope method. This helped every group act as age-sex-matched control against each other. The intra-oral, plaster study model, 3-D model, lateral cephalogram and OPG and were evaluated by four independent observers by preserving blinding.

Miles and Fleming reported insufficient strong evidence regarding superiority of SLBs over conventional brackets except for modest saving in chairside time.[1],[2] Nieto et al.[3] reported reduced treatment duration, friction, better oral hygiene and less chairside time. Turnbull and Birnie also showed that type of bracket and the size of wire are strong predictors for speed of ligation and chairside time.[4] Present study, however, demonstrated that SLB bracket system had slower rate of retraction when used either by friction or frictionless mechanics in comparison with conventional bracket though the result was not statistically significant.

Kuroda et al.[15] and Al-Sibaie et al.[16] reported no difference with two-step retraction versus en-mass retraction. Xu also reported en-mass retraction of upper anterior teeth using differential moments and TADs. Present study found that upper and lower molars migrated less in SLBs groups in comparison with their respective counterpart in conventional bracket system, which signifies better anchorage control with SLBs mechanics.

Davoody et al.[9] compared differential moments using CNA-based mushroom loop archwires and mini-screws assisted NiTi coil spring in anchorage control, reported greater anterior torque control in the differential moments group. Present study found significant difference among retraction of incisors in all four groups with a maximum in SLBs with TADs. This could be possibly due to low friction in SLBs as has been claimed in the past. However, further studies are required to confirm the finding.

Present study measured the rate of space closure by measuring the distance from mesial of canine bracket to distal of 1st molar tube as molar tubes and canine brackets were found to be a stable landmark. These landmarks were easy to replicate and less influenced by the subjectivity associated with rounding of cusp tips or poorly defined cusp tips, which could have caused intra- and inter-observer variability. Our study used plaster models, digitally scanned 3-D models and a direct intraoral measurement method simultaneously to evaluate the rate of extraction space closure, and found no significant measurement difference. Similar findings have been reported in the study by Nugrahani, Jazaldi and Noerhadi et al.[17] The present assessment was done on trial basis for the first time in our centre, which can subsequently pave way for phasing out of plaster models, thus saving material, space and time.

Liu and Guo compared the CBCT and OPG for assessment of tooth length and concluded the CBCT superiority over OPG.[18] Pandis et al.[5] had also reported satisfactory use of panoramic radiograph among the localisation of root resorption and showed the associated advantages of lesser radiation, availability and cost. Present study used root resorption assessment index proposed by Levander and Malmgren.[13] The index was found to be more simple, reliable and had added advantage of assessing entire dentition simultaneously on single OPG, against multiple IOPAs.

Makhlouf et al.[19] evaluated the amount of tooth movement and root resorption with friction versus frictionless mechanics and found no significant difference in root resorption among 'T' Loop and Niti coil spring group. Differences in modulus of elasticity between stainless steel and beta titanium have also been reported by Gupta et al.[20] as a cause of root resorption in orthodontics. The abovementioned studies were with either SLBs versus conventional brackets, or friction versus frictionless mechanics. Present study tried to combine all variables together and found grade 2 resorption. This could be due to the low LDR of CNA archwire and controlled force of 150 gm utilised for TADs supported NiTi coil springs.

For the subjective assessment of pain, previous studies reported reliability and reproducibility of VAS as a pain measurement tool.[10],[11] Hence, this study also utilised VAS method by using pain rating scale software available in the android software platform. With easy availability of cell phones, this software-based VAS analysis was found to be more accurate as data were recorded as per the schedule and archiving was easily retrievable.

Though the findings of the study were able to answer the research question to a certain extent, additional research involving a larger sample size is warranted to validate the outcomes.


   Conclusion Top


The present study found increased treatment duration with SLB along with friction mechanics, refuting the previous claims of reduced friction with SLBs; however, the difference was not statistically significant and results have to be extrapolated with caution and experience considering other advantages of SLBs such as better patient comfort, less pain and reduced chairside time.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

This paper is based on research grant sanctioned for AFMRC Project Number 4737/2016 vide O/o DGAMFS letter number 15965/4737/2016/DGAFMS/DG-3B dated 17 Oct 2016.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

1.
Miles PG. Self-ligating vs conventional twin brackets during en-masse space closure with sliding Mechanics. Am J Orthod Dentofacial Orthop 2007;132:223-5.  Back to cited text no. 1
    
2.
Fleming PS, DiBiase TA, Lee RT. Self-ligating appliances: Evolution or revolution?. J Clin Orthod 2008;42:641-51.  Back to cited text no. 2
    
3.
Nieto M, Barrera JP, González EJ, Parra IL, Rodríguez AC. Comparison of resistance to sliding produced by self-ligating brackets and conventional brackts ligated with conventional elastomeric ligature and low-friction ligatures. Rev Fac Odontol Univ Antioq 2012;23:192-206.  Back to cited text no. 3
    
4.
Turnbull NR, Birnie DJ. Treatment efficiency of conventional vs self-ligating brackets: Effects of archwire size and material. Am J Orthod Dentofacial Orthop 2007;131:395-99.  Back to cited text no. 4
    
5.
Pandis N, Nasika M, Polychronopoulou A, Eliades T. External apical root resorption in patients treated with conventional and self-ligating brackets. Am J Orthod Dentofacial Orthop 2008;134:646-51.  Back to cited text no. 5
    
6.
Scott P, DiBiase AT, Sherriff M, Cobourne MT. Alignment efficiency of Damon3 self-ligating and conventional orthodontic bracket systems: A randomized clinical trial. Am J Orthod Dentofacial Orthop 2008;134:470.e1-8.  Back to cited text no. 6
    
7.
Aras I, Unal I, Huniler G, Aras A. Root resorption due to orthodontic treatment using self-ligating and conventional brackets: A cone-beam computed tomography study. J Orofac Orthop 2018;79:181-90.  Back to cited text no. 7
    
8.
Upadhyay M, Yadav S, Patil S. Mini-implant anchorage for en-masse retraction of maxillary anterior teeth: A clinical cephalometric study. Am J Orthod Dentofacial Orthop 2008;134:803-10.  Back to cited text no. 8
    
9.
Davoody AR, Posada L, Utreja A, Janakiraman N, Neace WP, Uribe F, et al. A prospective comparative study between differential moments and miniscrews in anchorage control. Eur J Orthod 2013;35:568-76.  Back to cited text no. 9
    
10.
Xu TM, Zhang X, Oh HS, Boyd RL, Korn EL, Baumrind S. Randomized clinical trial comparing control of maxillary anchorage with 2 retraction techniques. Am J Orthod Dentofacial Orthop 2010;138:e541-9.  Back to cited text no. 10
    
11.
Sculz Altman DG, Moher D. CONSORT 2010 Statement: Updated guidelines for reporting parallel group randomised trial. BMC 2010;340:c332.  Back to cited text no. 11
    
12.
Lavender EM, Malmgren O, Evaluation of the risk of root resorption during orthodontic treatment: A study of upper incisors. Eur J Orthod 1988;10:30-8.  Back to cited text no. 12
    
13.
Maurya RK, Gupta A, Singh H, Thakkar S, Mishra H. Effects of 'low light laser' and 'light emitting diode' mediated 'photo-bio-dynamic' therapy on clinical & biomechanical efficiency of orthodontic mini-implants- A randomized control trial. J Clin Orthod 2017;51:259-69.  Back to cited text no. 13
    
14.
Maurya RK, Singh H, Sharma P, Kapoor P, Jain U, Mitra R. Effects of low-level laser and low intensity pulsed ultrasound therapy on orthodontic treatment duration and associated pain perception-A prospective split-mouth controlled clinical trial. J Clin Orthod 2019;53:156-62.  Back to cited text no. 14
    
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Kuroda S, Yamada K, Deguchi T, Kyung HM, Takano-Yamamoto T. Class II malocclusion treated with miniscrew anchorage: Comparison with traditional orthodontic mechanics outcomes. Am J Orthod Dentofac Orthop 2009;135:302-9.  Back to cited text no. 15
    
16.
Al-Sibaie S, Hajeer MY. Assessment of changes following en-masse retraction with mini-implants anchorage compared to two-step retraction with conventional anchorage in patients with class II division 1 malocclusion: A randomized controlled trial. Eur J Orthod 2014;36:275-83.  Back to cited text no. 16
    
17.
Nugrahani F, Jazaldi F, Noerhadi NAI. Comparison of conventional study model measurements and 3D digital study model measurements from laser scanned dental impressions. J Phys Conf Ser 2017;884:012060.  Back to cited text no. 17
    
18.
Liu Y, Guo HM. Comparison of root resorption between self-ligating and conventional brackets using cone-beam CT. Shanghai Kou Qiang Yi Xue 2016;25:238-41.  Back to cited text no. 18
    
19.
Makhlouf M, Aboul–Ezz A, Fayed MS, Hafez H. Evaluating the amount of tooth movement and root resorption during canine retraction with friction versus frictionless mechanics using cone beam computed tomography. Open Access Maced J Med Sci 2018;6:384-8.  Back to cited text no. 19
    
20.
Gupta G, Singh RK, Relhan A, Singh G, Goyal A. Comparison of apical root resorption encountered during maxillary incisor retraction using stainless steel boot loop and TMA boot loop – A case series. Orthodontic Journal of Nepal 2016;6:45-8.  Back to cited text no. 20
    

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Correspondence Address:
Dr. Harsh Ashok Mishra
Associate Professor, Department of Orthodontics and Dentofacial Orthopedics, Bharati Vidyapeeth (Deemed to be University) Dental College and Hospital, Navi Mumbai, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijdr.ijdr_1127_21

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