Evaluation of Treatment Duration of En-masse Versus Two Steps Retraction in Patients Having Maxillary Protrusion: A Randomized Clinical Trial
Phase: NA
Conditions: Bimaxillary Protrusion
Sponsor: Future University in Egypt

 
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Evaluation of treatment duration of En-masse versus 
Two steps Retraction in Patients having Maxillary 
Protrusion :  
A Randomized Clinical Trial 
 
 
 
Protocol submitted for the partial fulfillment of Masters’ degree in 
Orthodontics  
Faculty of Oral and Dental Medicine, Future University in cairo 
Submitted by 
 Aya Ahmed El Ashwal 
B.D.S. Misr International University, 2012 
 (2019) 
 
 
 
 
 
 

 
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Funding: 
 No sources of funding to be declared. 
Roles and responsibilities: 
Principal investigator: 
Aya A. El Ashwal, BDS, will be responsible for applying the sample recruitment, 
clinical procedures of both interventions that will be carried out, follow up of 
patients, data management, results interpretation and writing the thesis as well as 
protocol registration. 
Main supervisor:  
Dr. Nagwa El Mangoury, BDS, MSc, PhD - Department of Orthodontics and 
Dentofacial Orthopedics – Future University. Helped in developing the idea of the 
research, will help in interpretation of results and drawing conclusions. 
Co-supervisor:  
Dr. Faten H.K. Eid, BDS, MSc, PhD, professor - Department of Orthodontics and 
Dentofacial Orthopedics – Cairo University. Helped in setting the study design, will 
help in follow up of patients, creating analysis, interpretation of results and drawing 
conclusions and help writing thesis and supervision. 
Co-supervisor:  
Dr. Heba M. Dehis, BDS, MSc, PhD, Lecturer - Department of Orthodontics and 
Dentofacial Orthopedics – Cairo University. Will be responsible for implementation of 
random sequence generation, as well as allocation concealment. Additionally, will help 

 
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in follow up of patients, interpretation of results, drawing conclusions, as well as 
writing Thesis and protocol registration. 
All authors contributed to refinement of the study protocol. 
Committees: 
• Orthodontics Department Council 
• College Board Committee 
• Ethics Committee 
 
 

 
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Introduction 
Statement of the problem:  
Several orthodontic techniques have been used to treat patients with 
bimaxillary protrusion as well as class II division 1 cases. To resolve this problem 
extraction of first premolars and retraction of the anterior teeth is usually done, 
thus improve esthetics and lips competence. It is still debatable which technique is 
superior to the other, Two-step retraction (retraction of canine first followed by 
retraction of all four incisors) versus en masse retraction (retraction of the canines 
and incisors as one unit) (1) both techniques can be done by implementing either 
friction or frictionless mechanics.  
Rationale for carrying out the trial: 
In order to achieve patient satisfaction and shortest treatment duration, there 
is no gold standard guidelines which technique achieves the most efficient results 
at the shortest period of time of retraction. The first premolars are usually the main 
choice of extraction in bimaxillary protrusion cases, maximum anchorage of the 
posterior teeth become of great importance for two reasons; first to retract the 
anterior teeth to their greatest extent and second to increase the chances of 
correcting the profile maximum retraction of anterior teeth into the extraction 
space and retraction is the ideal treatment choice. (2,3)  
Space closure can be achieved by two methods either the two-steps (4) or by 
en-masse technique. A debate was raised between the two methods regarding 
friction mechanics.  

 
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         It has been recommended that two steps techniques  would provide less load 
on the posterior teeth thus minimal anchorage loss but on the other hand, separate 
canine retraction followed by incisors retraction would take longer time than 
closing it in a single step and it is aesthetically unacceptable (5) for some patient as 
there is a space after canine retraction and it persists up until the full retraction of 
anterior segment, for these reasons en-masse retraction is expected to be superior 
treatment option as retraction will be done by one step (6).  
          Nowadays, Orthodontists prefer using the en-masse technique because of its 
simplicity and the extraction space will be closed in one step so better aesthetics. 
But theoretically this technique may provide more loads on posterior segment so 
more risk of anchorage loss. 
          In general orthodontic treatment takes long time especially in extraction 
cases by average two years treatment time (7). So the longer treatment duration, 
the greater risks on the dentition by a way of root resorption (8), periodontal 
disease and enamel decalcifications (9). Thus, reduction of the treatment duration 
is of prime concern to both the patient as well as the orthodontist. 
For many years, practitioners have been looking for an efficient force system 
that can close extraction spaces quickly, aesthetically, accurately, and effectively. 
It was determined that both were effective methods for retraction (10). However, 
there is no evidence which technique offers shorter treatment duration with best 
retraction and space closure.  
Space closure can be done with two forms of mechanics: Friction or 
Frictionless mechanics, so knowing well biomechanics of force system is of great 
importance to close the extraction space without anchorage loss of posterior 
segment and avoiding any adverse effects on teeth roots. 

 
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Accordingly, the aim of the current randomized clinical trial (RCT) is to 
evaluate duration of en-masse retraction versus two steps retraction in adult patient 
having maxillary protrusion using friction mechanics. In addition to recording 
effects on root  resorption and anchorage loss for both techniques. 
Literature Review:
 
            Improvement in esthetic and facial profile is the main target of patients who 
seek orthodontic treatment to fulfill their satisfaction (11). Several approaches have 
been implemented to achieve the treatment that will result in proper mechanics 
with an increased rate of tooth movement.  However, extraction cases take time to 
be completed. Long treatment time to patients and orthodontics is one of 
drawbacks. Multiple studies have been conducted to evaluate the potency of 
different retraction methods.  
The review of literature will be discussed under the following titles: 
1- En masse retraction and two steps retraction 
2- Friction Mechanics 
3- 3D digital model scanning and its reliability 
 
 
 
 
 
 
 
 

 
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1) En masse retraction and two steps retraction 
 
          Heo W. et al. 2007 (12) compared the amount of anchorage loss of the 
maxillary posterior teeth and amount of retraction of the maxillary anterior teeth 
between en masse retraction and two-step retraction of the anterior teeth, 30 
female adult patients with Class I malocclusion and lip protrusion that needed 
maximum posterior anchorage. There were no significant differences in the 
degree of anchorage loss of the maxillary posterior teeth between the two 
groups. Bodily and mesial movements of the upper molars occurred in both 
groups. Approximately 4 mm of the retraction of the upper incisal edges resulted 
from 1 mm of anchorage loss in the upper molars in both groups. 
 
 
      Rizk MZ et al. 2018 (13) conducted a systematic review and meta-analysis 
to evaluate the the effectiveness of en masse and two-step retraction methods 
during orthodontic space closure regarding anchorage preservation and anterior 
segment retraction and to assess their effect on the duration of treatment and root 
resorption. An electronic search for potentially eligible randomized controlled 
trials and prospective controlled trials was performed in five electronic databases 
up to July 2017. The process of study selection, data extraction, and quality 
assessment was performed by two reviewers independently. A narrative review 
is presented in addition to a quantitative synthesis of the pooled results where 
possible. They conclude that Both en masse and two-step retraction methods are 
effective during the space closure phase. The en masse/miniscrew combination is 
superior to the two-step/conventional anchorage combination with regard to 
anchorage preservation and amount of retraction. Limited evidence suggests that 

 
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anchorage reinforcement with a headgear produces similar results with both 
retraction methods. Limited evidence also suggests that en masse retraction may 
require less time and that no significant differences exist in the amount of root 
resorption between the two methods.  
 
      Khlef HN et al. 2019 (14) carried out a systematic review and meta-analysis 
To evaluate the efficacy of accelerated and non-accelerated methods of en-masse 
retraction of the upper anterior teeth in terms of skeletal, dental, and soft-tissue 
variables, as well as the duration of retraction or overall orthodontic treatment. 
An electronic search of PubMed and nine other major databases for randomized 
controlled trials (RCTs) and clinical controlled trials (CCTs) was performed 
between January 1990 and April 2018. There is a weak to moderate evidence 
that using accelerated and non-accelerated methods would improve the facial 
profile and lead to similar skeletal corrections so according to the quality of 
evidence, there is a need for more well-conducted RCTs, and more work to be 
oriented towards en-masse retraction with the use of other acceleration methods. 
 
2) Friction Mechanics 
 
Barlow and Kuala 2008 (15) carried out a systematic review concerning 
the factors that affect the efficiency of closing an extraction space using sliding 
mechanics. Ten prospective clinical trials that compare the rates of closure under 
different variables and focus only on sliding mechanics were selected. The 
results showed that the clinical research was supported by laboratory results, 
where NiTi coil springs produce a more consistent force and a faster rate of 
closure when compared with active ligatures as a method of force delivery to 

 
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close extraction space. Moreover elastomeric chains was found to produce 
similar rates of closure compared to Ni-Ti Springs. Finally arch wire size has no 
effect on the rate of closure, although the larger wire sizes control tipping more 
effectively. 
 
Kanuru RK et al. 2014 (16)  carried out clinical study to investigate the 
amount of space closure by movement of canines into the extraction spaces using 
four brands of elastomeric power chains (EPCs) by intraoral application with 
pre-adjusted appliance for 6 weeks, namely the Ormco, 3M Unitek, Rocky 
Mountain, and Highland, which were closed-link with five loops delivering less 
than or equal to 250 g were used. The rates of canine retraction were measured 
between the attachment points on the canine bracket hook and first molar hook 
using a Mitutoyo Digital Vernier Caliper at the time of first application, after 3 
weeks of use, and at the end of 6 weeks of use, and were subjected to statistical 
calculations. Although all brands of the EPCs produced space closure of canines, 
it was observed that not much of a significant difference existed among the 
products tested. 
Chaudhari and Tarvade 2015 (17) compared the clinical effectiveness of 
nickelt titanium (NiTi) closed coil spring and elastomeric chain on the rate of 
space closure, taking into account the anterior retraction and the anchorage loss. 
Forty patients undergoing orthodontic treatment for bimaxillary proclination 
were randomly selected after first premolar extraction. They were then allocated 
to two groups: NiTi closed coil spring group versus Elastomeric chain group, 
with 20 candidates in each group. The results of the study showed that faster 
space closure with significant anchorage loss was achieved using NiTi closed 
coil spring compared to the elastomeric chain.  

 
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Al muzian et al. 2017 (18) conducted meta‐analysis to explore the 
effectiveness of nickel titanium closing springs and elastomeric power chains 
(EPC) in orthodontic space closure and to assess the adverse periodontal effects, 
cost efficiency and patient‐centred outcomes between both of these methods, and 
they concluded that both of NiTi closing springs and elastomeric chains are 
efficient force delivery systems in closing extraction space with space closure 
being the resultant of anterior teeth retraction, anchorage loss or combination. 
 
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3) 3D digital model scanning and its reliability       
El-Beialy and Mostafa Y.A.  2010 (19) compared the accuracy of dental 
measurements taken with calipers on 34 orthodontic plaster dental casts to those 
from computed tomography scans of the same dentition. The mesiodistal widths 
of teeth, arch widths, arch lengths, arch perimeters, and palatal depths were made 
with the calipers on a plaster cast. The patients were also scanned with computed 
tomography, and measurements were made digitally with 3DD, a 3-dimensional-
based dental measurements program. The results showed high correlation 
between the conventional method and the 3DD in all the 3 planes of space. Thus, 
3D dental measurement programs (such as the one used in this study) can be a 
valid alternative to conventional stone dental models. 
Kim et al. 2016 (20) analysed the accuracy of Bolton analysis obtained 
from digital models scanned with Ortho Insight (3D) laser scanner system in 
comparison to those obtained from cone beam computed tomography (CBCT) 

 
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images and traditional plaster models. CBCT scans and plaster model’s scans 
were obtained from fifty patients. Botlon ratios were calculated with the Ortho 
Insight 3D laser scanner software, CBCT scans were imported and analyzed 
using AVIZO software and plaster models were measured with a digital caliper. 
Laser scanned digital models were found to be highly accurate compared to 
physical models and CBCT scans for assessing the spatial relationship of dental 
arches for orthodontic diagnosis. 
 
 
 
 
 
 
Database search: 
A search was performed on electronic databases (PubMed, Cochrane library). 

 
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Aim of the study 
A-PICOS format: 
Population: 
Adolescent and adult orthodontic patients requiring first premolars extraction. 
Intervention: 
En-masse retraction using sliding mechanics (friction) with mini screws used as 
anchorage. 
Comparator: 
Two-steps retraction using sliding mechanics (friction) with mini screws used as 
anchorage. 
Outcome measure: 
 
Outcome Name 
Measuring Tool 
Measuring Unit 
Primary 
Outcome 
Duration of space 
closure 
Dental digital Model 
Records of visits  
 
 
- Scanned digital models in (mm) 
o Models taken every month 
o Analysed using 3 Shape 
Software 
- computerized record system of 
the recruited patient (months, 
days, years) 
 
 

 
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Secondary 
Outcomes 
Anchorage loss 
Digital models 
- Linear measurement in mm 
 
 
Pain 
Pain scoring sheets 
given to patients 
- VAS scoring from 1-10(Fig 1) 
 
B-Research question: 
Will en-masse retraction offer shorter treatment duration compared to two steps 
retraction, in patients having maxillary protrusion? 
 
 

 
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Objectives of the study 
Research hypothesis: 
The null hypothesis (H0) of this research is that there’s no difference between both 
en-masse and two steps techniques on duration of retraction during en-masse and 
two steps retraction following 1st premolar extraction. 
Primary objective: 
Evaluating the duration of En-masse and two steps retraction using friction 
mechanics. 
Secondary objectives: 
Assessing the amount of anchorage loss, pain and discomfort during retraction. In 
addition to this, of anterior teeth will be measured following en-masse and two 
steps retraction using friction mechanics. 
Study design: 
This is a randomized clinical trial with two arms parallel group, and 1:1 allocation 
ratio. In one group, will receive frictional mechanics during En masse retraction, 
while the other group will receive frictional mechanics during two steps retraction. 
The duration of retraction will then be compared between both interventions. 
 
 

 
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Material and Methods 
I) 
Participants, Interventions, and Outcomes 
A] Study Setting: 
The study will be performed in the clinic of the Orthodontic Department at the 
Faculty of Oral and Dental Medicine, Future University in Egypt. The recruited 
sample would be from the Egyptian urban and rural population. 
B] Eligibility criteria: 
 Inclusion criteria: for the participants include the following: 
 
1. Age range (14-24) 
2. Adolescent & Adult patients (both genders) 
3. Patients with maxillary protrusion requiring first premolars extraction 
(Bimaxillary Protrusion or Class II division 1 cases) as confirmed from 
lateral cephalometric, pre-treatment records & from clinical examination. 
4. Patients with fully erupted permanent teeth (not necessarily including the 
third molar). 
5. Cases requiring maximum anchorage during retraction.  
6. Minimal crowding 2-3 mm. 
 Exclusion Criteria: for the involved subjects included: 
 
1. Patients suffering from any systemic diseases interfering with tooth 
movement. 
2. Patients with extracted or missing permanent teeth. (Except for third 
molars). 
3. Patients with badly decayed teeth.  
4. Patients with any parafunctional habits (i.e. Bruxism, tongue thrusting, 
mouth breathing, etc…). 
5. Patients with previous orthodontic treatment. 
 

 
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*American Orthodontics  
* Jeil  Miniscrews 
C] Interventions: 
 
➢ Medical History Questionnaire: 
For every patient, to exclude the presence of any systemic condition 
interfering with orthodontic treatment.  
 
➢ Clinical Examination: 
Oral structures will be examined to identify caries, fracture or 
missing teeth.  Gingival tissues will be carefully examined for any 
gingivitis, periodontitis, recession, or lesions. 
 
➢ Diagnosis 
Check the potential patient to fulfill the previously mentioned 
inclusion criteria. Every participant will be asked to sign an informed 
consent about the study. Full set of records (study models, panorama 
radiograph and lateral cephalometric radiographs, photos) will be 
taken for every patient as part of the routine procedure for treatment 
of patients in the clinic of the Orthodontic Department, Future 
University in Egypt. 
 
➢ Clinical Procedure: 
 
After taking pre-treatment records, every patient will receive: 
 
• 
Miniscrews will then be placed in the upper arch between the second 
premolar and first molar. 
• 
The patient will be referred for extraction of first premolars. 

 
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• 
Anchorage will be secured, followed by Leveling and alignment for the 
bonded and banded teeth through following the wire sequence: 0.014 
NiTi, 0.016×0.022 NiTi and 0.017×0.025 StSt.  
• 
Bonding of all teeth except for first premolars and banding/bonding the 
first and second molars will be done using Roth prescription brackets 
(0.022 x 0.028 slot)*. 
• 
After leveling and aligning is completed (right before retraction), the 
patient will be referred for the uptake of pre-intervention records for en 
masse group (Impression for models, photos extra oral and intra oral and 
pain questionnaire). 
• 
For two step group canine retraction will take place on a 0.017×0.025 
StSt arch wire, once canine retraction stage is completed, the patient will 
be referred for the uptake of pre-intervention records. 
➢ Acquisition of pre-intervention records: 
• 
Alginate impressions will be taken before retraction (without the arch 
wire in place) followed by digital scanning of produced models. 
• 
Photos (Extra and intra oral). 
• 
Pain questionnaire distributed with explanatory session on it. 
➢ Begin of Retraction: 
 
• 
Crimpable hooks added to the arch wire (0.017”x0.025” Stainless steel) 
distal to the lateral incisor passing near the center of resistance of the 
anterior segment. 
• 
A ligature wire extending between the second premolar and miniscrews 
will be used for proper anchorage control. 

 
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• 
Retraction will start on a 0.017”x0.025” Stainless steel wire using 
elastomeric chain (force applied will be 200 g per side) (24) extending 
between the crimpable hooks and the molar hooks. 
• 
The force will be measured by a force gauge and reactivated every 4 
weeks maintaining constant force of retraction all over the retraction 
phase. 
 
➢ 
Follow up visits 
 
Patients will be asked to attend for follow up sessions every 4 weeks for: 
• 
Evaluation of miniscrews stability. 
 
• 
Replacement of the power chain to maintain a force of 200 gm per side for 
en masse group and 160 gm per side for two step group. 
 
• 
Impression taking to asseses amount of space closure. 
 
• 
Recording the pain scoring sheet. 
➢ Criteria for discontinuing or modifying the allocated intervention: 
 
In cases of prolonged swelling or pain related to the miniscrew, the patient 
will be given strict oral hygiene measures and may wait for three weeks 
before the beginning of retraction. 
In cases of loose or broken miniscrews, the screw will be removed and 
replace the miniscrew after total resolution of the inflammation. 
In case of non compliant patients. 
 

 
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 Post-retraction Questionnaire: 
 
 The patients of both groups will be asked to fill in questionnaires regarding 
their experience with their allocated technique, during the whole retraction 
period from day of extraction till the end of retraction. 
 Retraction records 
 
Following en-masse and two steps retaction, patients will be referred to the 
same radiology center to acquire the final cone-beam CT to assess the 
movement and inclination of anterior teeth. 
The final dental model will be used to assess the rate of retraction and molar 
anchorage loss achieved throughout the study. 
 
Criteria of ending the retraction 
• Class I canine relation 
• Normal overjet 
• Balanced facial profile 
• Closing extraction space 
 
 Material Used 
 
• American Orthodontics Brackets, Roth prescription, 22 slot size. 
• American Orthodontics Elastomeric power chains 
• American Orthodontics Elastomeric O-ties  
• American Orthodontics Ligature wire. 

 
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• Miniscrew, 8 mm length x 1.6mm diameter TAD (Jeil).  
• American Orthodontics Arch wires.  
• American Orthodontics Molar bands/tubes.  
D] Outcomes 
Primary outcome: is to monitor the Duration of space closure during en-masse 
and two steps retraction. All outcomes will be assessed as the difference between  
T0 at the start of retraction and T1 after complete space closure. 
 
Secondary outcomes: is to monitor the changes in the anterior teeth position 
(final anterior teeth tip, torque and vertical position), anchorage loss, presence 
of any root resorption and pain associated with the different methods used for 
retraction.  
E] Participant timeline: 
1. The principle investigator will screen the potential patients through careful 
clinical examination of patients at the orthodontic department, Faculty of 
Oral and Dental Medicine, Future University in Egypt.  
2. All recruited patients should fulfil the previously mentioned inclusion and 
exclusion criteria.  
3. Every participant will be asked to sign an informed consent before the 
beginning of the study.  
4. After patient's enrolment, each participant will be asked for pre-intervention 
records to ensure proper diagnosis.  
5. The principle investigator will randomly allocate the patients to one of the 
intervention groups.  

 
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6. Anchorage will be secured by placement of miniscrew, followed by 
extraction of the first premolar. 
7. Active intervention will begin after proper levelling and alignment of the 
upper arch.  
8. The principle investigator will take pre-retraction records for every 
participant T0.  
9. Power chain is used for anterior segment retraction.  
10. Each patient will come every 4weeks for follow up visit, for appliance 
activation and uptake of impression for interim records + monitoring of 
recording the VAS sheet. 
11. After complete space closure, the principle investigator will take post-
retraction records for each participant T1.  
12. Every patient will fill up a questionnaire regarding his experience during 
treatment.  
13. The principle investigator will continue the normal treatment and achieve 
proper finishing for every patient after the end of the study. 
 

 
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Screening of patients seeking 
orthodontic treatment at the 
orthodontic department outpatient 
Patient enrollment 
Pre-intervention records 
Concealed Allocation 
Miniscrewplacement , extraction, 
leveling and alignment.  
En masse group 
Two steps group 
Activation of PC  
Acquisition of post-retraction 
Patient questionnaire 
Data collection and management 
Recruitment 
Preparatory phase 
Interventions 
Follow up visits 
End of study 
Eligibility criteria and 
informed consent  
Average 9 months 
After complete 
retraction 
Dropouts and missed 
data recorded 
Monthly follow up visits 
for activation 
Pre-retraction record 
Missed appointment 
records 

 
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F] Sample size calculation: 
Our sample size calculation is based on a previous study comparing the effect of 
En masse versus two-steps using friction and frictionless mechanics24. Using PS 
software output, we are planning a study of a continuous response variable from 
independent Group I and Group II subjects with 1 Group I(s) per Group II subject. 
In a previous study the response within each subject group was normally 
distributed with standard deviation 0.76. If the true difference in the Group II and 
Group I means is 1.0, we will need to study 10 Group II subjects and 10 Group I 
subjects to be able to reject the null hypothesis that the population means of the 
Group II and Group I are equal with probability (power) 0.8. The Type I error 
probability associated with this test of this null hypothesis is 0.05. Considering 
drop out a sample size 15 per group is appropriate. 
G] Recruitment strategy:  
The principal investigator will recruit the patients from the clinic of Orthodontic 
department, Faculty of Oral and Dental Medicine- Future University in Egypt.  
Screening of patients will continue until the total number of participants for the 
study is collected.  
II) Assignment of interventions: 
A] Sequence generation:  
The supervisor of the study will apply Computer generated random numbers to 
randomly assign patients to group A (En-masse) or B (two steps) using Microsoft 
Office Excel 2007 sheet. The patient numbers will be written in the first column 
and the supervisor will select function RAND to generate the randomization 

 
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number in the second column. These numbers will be sorted according to the 
randomization number so the first column numbers will be randomly distributed.  
 
B] Allocation concealment mechanism:  
The Co-supervisor of the study (Dr. Heba M. Dehis) will write the randomization 
numbers of the patients on opaque white papers folded three times to form sealed 
envelopes and store it inside a box. The codes for randomization will be securely 
held at the secretary’s office.  
 
C] Implementation:  
At the time of intervention, the main operator will send the patient to the 
secretary’s office. Then, the assigned employee will open the box and ask the 
patient to select one envelope. The main operator will contact the supervisor to 
know the order and then the main operator will allocate each patient to assign each 
participant for the corresponding intervention either (En-masse or two steps group) 
according to the list of codes of randomization.  
Assignment to either intervention will occur before levelling and alignment stage.  
 
D] Blinding:  
Blinding of the operators:  Blinding will not be possible for the operators during 
the application interventions and during the follow up visits. The principal operator 
is responsible for assigning subjects to interventions according to the concealed 
allocation, appliance activation at follow up visits, dental impressions and 
acquisition of dental casts.  
Blinding of the outcome assessors:  It is a single blinded study, therefore, only 
the outcome assessors will be blind. The patients name will be sealed from pre and 

 
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post radiographs and study models. Then two assessors will carry out, blindly and 
independently, the measurements and analysis of the study. 
III) Data collection, management and analysis: 
 
A] Data collection methods:  
 
Primary outcomes: 
1. Total Retraction Duration: to assess the timing of antero-posterior movement 
of anterior teeth and first molars, the principle investigator will take study models 
for every participant monthly during the follow up visits. Then will digitize the 
models and identify the landmarks, reference lines and planes on the pre, interim 
and post-retraction digital dental models for measurements reading. Also, by 
identifying the landmarks, reference lines and planes using CBCT taken before and 
after the completion of retraction. 
 
Secondary outcome:  
 
1.  Anchorage loss: will be accessed by the principal investigator via CBCT taken 
before and after the completion of retraction by identifying the landmarks, 
reference lines and planes, then will interpret the measurements in degrees and 
millimeters. 
2. Pain: Each patient will fill a questionnaire regarding his treatment experience in 
a VAS scoring from 1-10. The questionnaire will include several questions related 
to oral hygiene, pain and discomfort experienced throughout the trial. 
 
 

 
26 
 
B] Data management:  
A colleague outside the research team will enter the data and organize it in excel 
sheets in the computer of the orthodontic department.  
Data will include all photographs, models, radiographs and filled questionnaire.  
 
C] Statistical Analysis:  
• The principle investigator will be responsible for the extraction of the required 
data from the CBCT taken before and after retraction as well as the study models 
taken at every follow up visit. The data will be sent to a specialized statistician.  
• The specialized statistician will be responsible for the statistical analysis of the 
study by:  
 
1. Presenting the data as mean, standard deviation (SD) and Standard error (SE) 
values.  
2. Using Paired t-test to compare between the friction and the frictionless group of 
retraction as well as to compare between the pre-and post -treatment data for each 
group.  
3. Using Anova test to determine the rate of anterior segment retraction.  
4. Statistically evaluate the patient acceptance for both techniques.  
• For this study, the specialized statistician will use IBM11 SPSS12 Statistics 
Version 20 for Windows to perform the required statistics.  
• The significance level will be P ≤ 0.05. Highly significant variables are detected 
when P value is less than 0.01.  
 
 

 
27 
 
Assessors Reliability:  
• To achieve high reliability for measurements, the supervisor will choose a well-
experienced inter-examiner during the study.  
• A training session will be provided for the examiners to ensure standard 
measurements techniques.  
• Each examiner will complete the measurements on a model and will repeat the 
procedure after one week to assess the intra- and inter-examiner reliability.  
• The supervisor will compare the measurements of the two assessors for 
disagreement with a difference of more than one millimeter.  
• The supervisor will evaluate the amount of variation in measurements among and 
between examiners to test the performance of each assessor.  
• The examiner with less reliability will receive additional training but will be 
replaced during the study.  
• The specialized statistician will calibrate the intra and inter-examiner reliability 
for the measurements of the study by the Intra-class correlation coefficient (ICC). 
The closer the ICC to 1.0, the higher reliability between assessors. According to 
Fleiss:" ICC values between 0.7 and 0.9 represent good reliability." The kappa 
scores between study examiners will be calculated, a range of 0.60-0.80 will 
represent acceptable reliability.  
 
IV) Method Monitoring:  
A] Data Monitoring: An independent Data Monitoring Committee (DMC) will 
monitor the results of the study. The Committee will include the trial’s supervisors, 
who will periodically review the trial data and identify the need for any 
adjustments or modifications during the study.  

 
28 
 
 
B] Interim Analysis: no interim analysis will be performed during the study.  
 
C] Harm: The main operator will document and report any harms or unwanted 
effects during the study intervention to the trial supervisors. Also any unpleasant 
experience will be reported by the patient in the final questionnaire at the end of 
the retraction. The main operator will be responsible for the management of any 
adverse effects or unfavorable side effects resulting from the appliance. 
 
D] Auditing: The supervisor will follow up and review the different interventions 
and resulting data. And he will periodically follow up the trial progress including 
recruitment of patients, allocation of participants to study groups; adherence to 
interventions and reporting of harms. A meeting with the senior supervisor will be 
set every 3 months to monitor the progress of the study and the need for any 
adjustments. 
 
V) Ethics and dissemination:  
A] Research Ethics Approval:  
The Ethical committee in Future University, Egypt will review the protocol before 
they approve it. The research Ethics committee will evaluate the different 
interventions of the study to ensure its ethical validity and the potential benefits to 
the participants. 
B] Protocol amendments:  
The main investigator will be responsible to complete a formal amendment in case 
of any modifications or adjustments to protocol that may affect the conduct of the 
study, as changes in the study design or intervention procedures. The Orthodontics 

 
29 
 
department, Faculty of Oral and Dental Medicine, Future University in Egypt and 
the Ethics Committee will approve such amendment before proceeding in the 
study. 
C] Consent:  
The main investigator will be in charge for detailed explanation and elaboration of 
the different steps of the study interventions for each patient. Then will ask every 
participant to sign a written consent before they begin treatment. The consent will 
be written in Arabic.  
D] Confidentiality:  
The main investigator will store any personal information about the participants 
collected during the study separately from study records in locked files in areas 
with only access to the supervisors responsible for auditing and analysis. Also, will 
keep the files in the Department Of Orthodontics, Faculty of Oral and Dental 
Medicine, Future University and will identify all the reports, data and 
administrative forms by a coded ID number to maintain participant confidentiality. 
Participant information won't be used outside the study except with written 
permission of the participant.  
E] Declaration of interests:  
No financial interests are to be declared by the supervisors and the principle 
operator. This study is a part of a Masters’ degree in Orthodontics, Faculty of Oral 
and Dental Medicine, Future University and it is self-funded by the principal 
investigator.  
F] Access to data:  
The supervisors and the principal investigator will only have access to the data of 
the study. All the data will be secured by a password to maintain confidentiality. 

 
30 
 
No other parties are allowed to assess the results until the study is terminated and 
the conclusions are revealed.  
 
G] Ancillary and post-trial care:  
Any complication associated with the intervention will be managed by the 
principal operator. Then the two group of patients will continue their regular 
orthodontic treatment according to the treatment plan described for each case. 
H] Dissemination Policy:  
The trial results will be available to the participants, health care professionals and 
the public by publication of the study in high quality national and international 
journals. The principal investigator will present a copy of the thesis at the Faculty 
of Oral and Dental Medicine, Future University library and will distribute 
additional copies among the main universities in Egypt. 
 
 
 
 
 
 
 
 
 
 
 

 
31 
 
 
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