Three-Dimensional Evaluation of Clear Aligners Versus Fixed Orthodontic Treatment of Lower Anterior Crowding: A Randomized Clinical Trial
Phase: NA
Conditions: Pathological Resorption of External Root
Sponsor: Haidy Fekry

 
Three-Dimensional Evaluation of Clear Aligners versus Fixed 
Orthodontic Treatment of Lower Anterior Crowding: A 
randomized clinical trial 
        A Proposal 
Submitted to the Faculty of Dental Medicine for Girls, Al- Azhar University in 
Partial Fulfillment of the Requirement for Master Degree 
In 
Orthodontics 
          
By 
Haidy Fekry khairy Elsayed 
BDS 2014 faculty of dentistry Al mansoura university 
Dentist at Ministry of Health 
Orthodontic department  
Faculty of Dental Medicine for Girls 
Al-Azhar University 
1443H- 2022G 
Date  1/4/2022 
 
Code 
ORTHO-109-2-I 

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Supervisors 
 
Prof. Dr. Samir Abdo Ibrahim 
Professor and Head of Orthodontic Department 
Faculty of Dental Medicine for Girls 
Al-Azhar University 
Cairo, Egypt 
 
 
Dr. Sara M. Hosny El_kabbany 
Lecturer at Orthodontic Department 
Faculty of Dental Medicine for Girls 
Al-Azhar University, 
Cairo, Egypt 
 
Dr.Nora Abd El Gawad Mohamed 
Lecture of oral Medicine, Periodontology,  
Oral Diagnosis and Oral Radilogy 
Faculty of Dental Medicine, Girls, 
Al-Azhar University 
Cairo, Egypt 
 
 

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Introduction 
Orthodontic treatment is one of the most essential and effective ways to 
make individual smile in to radiant and more attractive smile. Influence of 
appearance in personal and orthodontist lives have led to a considerable interest 
among the adult population seeking orthodontic treatment in the last few year. 
Clear aligner’s technique (CAT) is the new age of aesthetic orthodontic 
treatment methods developed especially for adults who are very self-conscious 
of how they appear. 
  
A beautiful and attractive smile is known to have a positive effect on 
individuals. It also improves self-confidence, communicative success, careers, 
and private life. Thus, smile design aims to give a beautiful, healthy, ideal smile 
through a combination of medicine and art.(1) 
 
 The etiology of malocclusion can be broadly categorized under either 
hereditary, environmental, or a combination of both factors. Exploring the 
etiology of malocclusion is imperative for selecting the most appropriate 
treatment approach as well as the most appropriate retention device. Crowding 
and spacing are considered the most common manifestations of malocclusion (2-
4) 
Dental crowding can be defined as a disparity in the relationship between 
the tooth size and jaw size which result in the imbrications and rotation of teeth. 
Tooth size-arch length discrepancy (TSALD) is a well-defined means of 
assessing dental crowding . The factors that may predispose to crowding of 
teeth are large sized teeth, small bony bases or the combination of the above 
two, or as the result of an evolutionary trend towards a reduced facial skeletal 
size without a corresponding decrease in tooth size.(5) 
Mandibular crowding can be resolved by interproximal reduction (IPR) 
or proclination of the mandibular labial segment. Excessive proclination can 

4 
 
cause poor esthetics, gingival recession, and unstable results. It is important to 
ascertain how much proclination an individual orthodontic appliance 
produces.(6) 
 Newer wires and innovations in the bracket systems have simplified and 
reduced the time span of the aligning stage. One such innovation is Nickel 
titanium (NiTi) wires with the advantages of super elasticity, torsional strength, 
stress constancy, physiological compatibility, shape memory, dynamic 
interference, and wear resistance hysteresis.(7)  
Influence of appearance in personal and orthodontist lives have led to a 
considerable interest among the adult population seeking orthodontic treatment 
in the last few years. The clear aligners therapy is the most aesthetic treatment 
nowadays. The frequency of malocclusions in adults is equal to or greater than 
that observed in children and adolescents . (8-9)  
The history of clear aligners is back to 1945, when Dr. H. D. Kesling first 
proposed a clear, vacuum-formed tooth-positioning appliance for minor tooth 
movement. It was a labor-intensive process that required manually repositioning 
teeth reset in wax, and a clear vacuum-formed retainer was made for every tooth 
movement in a series of stages until the teeth were aligned. This technique was 
capable of minor tooth alignment. However, the amount of labor required for 
the task precluded its use on a wide scale, particularly for correction of more 
complex malocclusions (10).  
The workflow for clear aligner therapy traditionally uses a single intraoral 
impression or digital scan to generate multiple digital setups. These setups are 
then 3-dimensionally (3D) printed as a series of dental models onto which clear 
plastic aligners can be manufactured through thermoforming(11).  
Aligners are indicated for patients with mild to moderate crowding, 
spacing, non-skeletal constricted arches and in relapsed cases after fixed 

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appliance therapy.  In addition, patients with nickel allergies are good 
candidates for clear aligners, since traditional brackets and wires contain some 
component of nickel in stainless steel. Also, due to the aligners being removable 
by concept, less oral hygiene maintenance issues are likely to be encountered, 
making patients with special needs good candidates for such appliances. (12-14) 
When treatment with aligners was compared to that involving fixed 
orthodontic appliances in adult populations, several studies showed that the use 
of aligners resulted in significantly poorer outcomes, whereas others 
demonstrated near equal efficacy of the two treatment approaches. The previous 
studies were based on treatment of adults with varying ranges of malocclusion 
severity, using earlier generations of aligner technology. (15-19) 
Despite over 15 years of commercial availability and many millions of 
cases treated worldwide, very little research has assessed how clear aligners 
achieve their results.(20) 
For this reason, this study will be conducted using CBCT  to assess the 
effects of orthodontic treatment with clear aligners, as compared to that with 
NITI arch wires in the treatment of lower anterior teeth crowding. 
 
 
 
 
 
 
 
 

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Aim of the study  
The present study will be performed to: 
    Evaluate and compare clear aligners versus fixed orthodontic treatment of 
lower anterior crowding with the use of  CBCT within maximum 6 months or 
until correction of lower anterior crowding whichever is nearest to occur. 
 
 
 
 
 
 
 
 
 
 
 
                                          
 
 
 
 

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Subjects and methods 
Patients with lower anterior crowding will be collected from Orthodontic 
Clinic and Faculty of Dental Medicine for Girls, Al-Azhar University.  
Study design: Randomized Clinical Trial. 
  
Randomization will be done by using Microsoft Office Excel 2007 . 
patients information  will be entered into a computer ,then the computer 
randomly assigns the patients to two groups that helping to prevent bias. 
  
Control group (n=10) patients will receive  a conventional therapy with 
fixed appliances  and  the investigational  group (n=10) will receives the new 
treatment therapy by using clear aligners for the treatment of mild to moderate 
lower anterior crowding. 
Eligibility criteria: 
Inculsion criteria(21): 
1.Adult female patients (CVMI  stage 6).  
2.Patients with mild to moderate lower anterior crowding. 
3. Healthy compliant and motivated patient. 
4.No missing of any tooth except wisdom teeth. 
Exclusion criteria(21): 
1. Previous orthodontic treatments. 
2. Any systemic or bone diseases. 
3. Pregnant and lactating patient. 
4. Prosthetic replacement in lower anterior teeth. 
5.periodontitis with pocket depth more than 5 mm. 

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Method: 
The following record will be taken for each patient before delivery 
appliance: 
 Upper and lower orthodontic cast.  
 CBCT. 
 Intraoral and extraoral photography. 
Treatment groups: 
Group (A): Patients will be treated with conventional fixed orthodontic 
treatment in lower anterior crowding.  
Group (B): Patients will be treated with clear aligner therapy in lower 
anterior crowding. 
Sample size calculation: 
Based on Bhatia (21) and Using G power statistical power Analysis  
program (version 3.1.9.4) for sample size determination, A total sample size 
(n=20; subdivided to 10 in each group) will be sufficient to detect a large effect 
size  (d) ranging from 1.32 to 1.4, with an actual  power (1-β error) of 0.8 (80%) 
and a significance level (α error) 0.05 (5%) for two-sided hypothesis test.  
Ethical approval: 
The research protocol approved by ethical committee of Faculty of Dental 
Medicine, girls, Al-Azhar University, (P-OR-22-01). The steps of the procedure 
will be explained to the patients / parents and an informed consent will be 
signed .      
References 

9 
 
1.Turpin D L. Orthodontic treatment and self-esteem. Am J Orthod Dentofacial 
Orthop. 2007; 131: 571–2. 
2.McKeever A. Genetics versus environment in the etiology of malocclusion. 
Br Dent J. 2012;8:527-8. 
3.Amini F, Borzabadi-Farahani A. Heritability of dental and skeletal 
cephalometric variables in monozygous and dizygous Iranian twins. Orthod 
Waves. 2009;68:72-9. 
4.Proffit WR, Fields HW. Sarver DM. Contemporary Orthodontics. 6 th ed. St. 
Louis: Elsevier; 2018. 
5.Warren JJ, Bishara SE, Yonezu T. Tooth size-arch length relationships in 
the deciduous dentition: a comparison between contemporary and historical 
samples. Am J Orthod Dentofacial Orthop. 2003;123;614-9. 
6.Pandis N, Polychronopoulou A, Makou M, Eliades T . Mandibular dental 
arch changes associated with treatment of crowding using self-ligating and 
conventional brackets. Eur J Orthod. 2010;32:248–53. 
7.Rucker BK, Kusy RP. Elastic flexural properties of multistranded stainless 
steel versus conventional nickel titanium archwires. Angle Orthod. 
Aug.2002;72: 302-9 
8.Vijayaalakshmi LG, Sumathifelicita A. Clear Aligners in Orthodontics. 
International Journal of Management, IT & Engineering. 2017; 7: 484-7. 
9.Alikhani M, Alansari S, Hamidaddin MA, Sangsuwon C, Alyami B, 
Thirumoorthy SN et al. Vibration paradox in orthodontics: Anabolic and 
catabolic effects. PLoS ONE. 2018; 13: 19-6540. 
10.Al-Sabbagh, Rabab ,Nour Al-Obaid. Diagnosis and management of 
crowding of teeth by clear aligners: A case report. 2019 ; 5: 326-30.‏ 
11.Jindal P ,Juneja M ,Siena FL ,Bajaj D ,Breedon P. Mechanical and 

10 
 
geometric properties of thermoformed and 3D printed clear dental aligners. Am 
J Orthod Dentofacial Orthop. 2019;156:694-701. 
12.Boyd R.L. Esthetic Orthodontic Treatment Using the InvisalignTM Appliance 
for Moderate to Complex Malocclusions. J Dental Education.2001;72:948-67. 
13.Joffe L.Current Products and Practice InvisalignTM: early experiences. J 
Orthod.2003;30: 348–52. 
14.Acar Y.B, Kovan A.I, Atesx M . How Efficient Are Clear Aligners? Clear 
Aligners v/s Traditional Orthodontic Treatment; A Systematic Review: Turkish 
J Orthod. 2015;27:106–10. 
15.Pavoni C ,Lione R ,Lagana G ,Cozza P. Self-ligating versus Invisalign: 
analysis of dentoalveolar effects. Ann Stomatol .2011; 2: 23–7 . 
16.Djeu G ,Shelton C ,Maganzini A. Outcomes assessment of Invisalign and 
traditional orthodontic treatment compared with the American Board of 
Orthodontics objective grading system. Am J Orthod Dentofacial Orthop. 2005; 
128: 292–8 . 
17.Gu J ,Tang JS , Skulski B . Evaluation of Invisalign treatment effectiveness 
and efficiency compared with conventional fixed appliances using the Peer 
Assessment Rating Index Am J Orthod Dentofacial Orthop. 2017; 151: 259–66. 
18.Li W,Wang S,Zhang Y. The effectiveness of the Invisalign appliance in 
extraction cases using the ABO model grading system: a multicenter 
randomized controlled trial. Int J Clin Exp Med. 2015; 8: 8276–82. 
19.Hennessy J,Garvey T,Al-Awadhi EA. A randomized clinical trial 
comparing mandibular incisor proclination produced by fixed labial appliances 
and clear aligners. Angle Orthod. 2016; 86: 706–12. 
20.Djeu G, Shelton C, Maganzini A. Outcome assessment of Invisalign and 
traditional orthodontic treatment compared with the American Board of 

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Orthodontics objective grading system. Am J Orthod Dentofacial Orthop. 
2005;128:292–8. 
21.Bhatia S ,Singh G ,Izhar A ,Goyal V ,Singh R ,Gupta N . To Evaluate and 
Compare the Aligning Efficiency of Clear Aligners and Nickel Titanium Arch 
Wires In Unraveling Lower Anterior Crowding - A Prospective Study J of 
Contemporary Ortho,2019; 3: 20-25. 
 
 
 
 
 
 
 
 
 
 
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