Comparison of Perforated 3D Printed Metal Fixed Mandibular Retainer Versus Conventional Fixed Bonded Retainer A Randomized Clinical Trial
Phase: NA
Conditions: Bond, Pair
Sponsor: Mariam Alaa

 
1 
 
 
 
Comparison of Perforated 3D Printed Metal Fixed Mandibular 
Retainer versus Conventional Fixed Bonded Retainer 
 A Randomized Clinical Trial  
 
تقييم سلك تثبيت الفك السفلي المعدني المثقب المطبوع ثالثي األبعاد مقابل سلك التثب يت
التقليدي
تجربة سريرية عشوائية 
 
 
Protocol submitted to  
Faculty of Dentistry, Cairo University 
for partial fulfillment of the requirements for the PhD Degree in 
Orthodontics 
 
By 
Mariam Alaa El Din Abdel Aziz 
BDS (2013), MSc (2020) 
 
1/11/2024 
 
 
 
 
Supervisors’ signature 
Head of department’s signature 
1- 
 
 
2- 
 
 
3- 
 
 
 
 
Date 
 
 
 
 
 
 
Code:  Orth 3-3-2 

 
2 
 
Protocol checklist 
Section and topic 
Item no. 
Checked item 
Reported 
on page No. 
Reviewer’s 
check 
I. Administrative information 
1 
Title 
  
 
2 
Protocol registration 
 
 
3 
Protocol version 
 
 
4 
Funding 
 
 
5 
Roles and responsibilities 
 
 
 
II. Introduction 
 
 
 
A) Background and Rationale 
6 a 
Research question  
 
 
Statement of the problem 
 
 
Rationale for carrying out the trial 
 
 
Review of literature 
 
 
6 b 
Choice of comparators 
 
 
B) Objectives 
7 
Aim of the study  
 
 
Hypothesis 
 
 
C) Trial design 
8 
Trial design 
 
 
 
III. Methods 
 
 
 
A) Participants, interventions 
& outcomes 
9 
Study setting 
 
 
10 
Eligibility criteria 
 
 
11 
Interventions 
 
 
12 
Outcomes 
 
 
13 
Participant timeline 
 
 
14 
Sample size 
 
 
15 
Recruitment 
 
 
B) Assignment of interventions 
16 
Allocation 
 
 
16 a 
Random sequence generation 
(Randomization) 
 
 
16 b 
Allocation concealment 
mechanism 
 
 
16 c 
Implementation 
 
 
17 
Blinding (masking) 
 
 
C) Data collection, 
management, and analysis 
18 
Data collection methods 
 
 
19 
Data management 
 
 
20 
Statistical methods 
 
 
D) Monitoring 
21 
Data monitoring 
 
 
22 
Harms 
 
 
23 
Auditing 
 
 
 
IV. Ethics and dissemination 
24 
Research ethics approval 
 
 
25 
Protocol amendments 
 
 
26 
Informed Consent  
 
 

 
3 
 
 
 
 
 
 
 
 
 
 
 
 
27 
Confidentiality 
 
 
28 
Declaration of interests 
 
 
29 
Access to data 
 
 
30 
Ancillary and post-trial care 
 
 
31 
Dissemination policy 
 
 
 
V. Appendices 
 
32 
Informed consent materials 
 
 
 
33 
Biological specimens 
 
 
 
VI. Statement of originality 
34 
Statement of originality 
 
 
VII. References 
 
 
 
 
 
 
Evidence based committee (Reviewers) 
 
Name 
Signature 
Date 
1. 
 
 
 
2. 
 
 
 
 
Research plan committee 
 
Name 
Signature 
Date 
1.  
 
 
 
2.  
 
 
 

 
4 
 
I. Administrative information: 
1. Title:  
Evaluation of 3D Printed Metal Fixed Mandibular Retainer versus Conventional Fixed 
Bonded Retainer :A Randomized Clinical Trial  
 
2. Protocol Registration:  
Trial will be registered in www.clinicaltrials.gov. 
 
3. Protocol version:  
2024, Protocol Number: 1. 
 
4. Funding:  
Self-funding. 
 
5. Roles and responsibilities: 
Mariam El-Sebaay, BDS (Principle Investigator): will be responsible for clinical work of the 
study, follow up the patients, writing the thesis, interpretation of results and drawing 
conclusions. 
Khaled Hazem BDS, MSc, PhD (main supervisor): helped in setting the study design, 
developing the idea of the research, will help diagnosis of the sample, interpretation of results 
and drawing conclusions. 
Amr Ragab El-Beialy, BDS, MSc, PhD (Co-supervisor): will help in carrying out the 
measurements twice to measure the intraobserver error. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
5 
II. Introduction: 
6. Background and rationale: 
              Achieving long-term stability of the orthodontic treatment is a significant challenge 
for many reasons such as age related changes or excessive arch expansion during orthodontic 
treatment especially in mandibular intercanine area1. Many studies have shown that long-term 
stability is problematic when retention is discontinued, with some degree of inevitable relapse 
inevitable2. Therefore, the use of long-term retention has been recommended because some 
patients would not tolerate minor irregularities of teeth3. Thus, fixed retainers can be used for 
long-term retention with minimal patient compliance4. 
             Although many studies have shown that fixed retainers are safe and compatible with 
periodontal health, there are several complications of fixed retainers. These complications 
include failure of bonded retainer which may occur due to debonding of the composite 
adhesive from the tooth, failure of the bond between the wire and the composite, or fracture of 
the retainer. Failure rates may be affected by clinical technique, the choice of retainer design 
and material, adhesive used and the location of the retainer5,6. Fixed retainers may also result 
in adverse periodontal effects such as inflammation, bone resorption or gingival health7. 
Moreover, unwanted tooth movements were also recognized with bonded retainers in situ 
Unwanted tooth movement with the retainer in situ8. 
            There is a lack of consensus among orthodontists regarding the optimal type of retainer 
wire regarding design and material9. The most commonly used materials for fixed retainers 
are either flexible multi-strand stainless steel wires bonded to all the anterior teeth, or thick 
monofilament stainless steel, cobalt-chromium or titanium-molybdenum wires bonded only on 
the canines. All multi-strand wires fulfil the criteria of having mechanical properties of the 
wire that allow physiological movement of included teeth while sufficiently splinting the teeth 
at the same time.; however, small diameter wires with fewer filaments are more susceptible to 
damage and have been reported to have increased failure rate due to lower bond strength and 
mechanical instability10. Retainers bonded only to canines are also easier to keep clean10. 
However, because they are not attached to the incisors, these teeth are more prone to 
movement11. Fibre-reinforced composite, fibre-reinforced plastic or even ceramic materials 
can be used. However, fibre-reinforced retainers are prone to greater failure rates due to a lack 
of flexibility unlike dead soft stainless steel wires12.More recently, monofilament nickel-
titanium wires constructed by CAD/CAM procedures have been described and are currently 
being investigated13. 
            Several studies were conducted to reach a reproducible technique with standard 
results; however, none have reached the most reliable technique because of the human factor 
that can’t be excluded and the evolution of different materials with various properties that can 
be used for fabrication of fixed retention wire. Digitization was recently introduced in 
orthodontic field with the evolution of 3D imaging & printing machinery. These new 
technologies offer superb accuracy as well as elimination of errors emerging from human 
variations. Intraoral scanner devices offer numerous applications in orthodontics such as 
digital storage of study models and advanced software for designing different designs of fixed 
retention wire, enabling fabrication of three dimensionally printed fixed lingual retention wire. 
Therefore, utilization of 3D imaging and metal printing techniques can help the orthodontist to 

 
6 
reach the most precise and reproducible design of lingual retention wire with more accurate 
and standard results. 
            Thus to overcome previously mentioned problems of conventional lingual retention 
wire, this study is conducted in an attempt to evaluate bond failure immediately and after 12 
months follow up of novel three dimensionally metal printed fixed retention wire compared to 
conventional lingual wire. 
Research question:  
Will the 3D metal printed retainer reduce the immediate bond failure and bond failure after 12 
months in patients with need of fixed bonded mandibular retainer, when compared to 
conventional fixed bonded mandibular retainer?  
Statement of the problem:  
 
Although different materials of mandibular fixed retainer were discussed in the literature, 
there is contradicting evidence regarding the bond failure of Titanium fixed metal retainer, 
whether immediate or after 12 months. Moreover, insufficient evidence is present regarding 
3D metal printed fixed mandibular retainers.  
Rationale for conducting the research: 
To evaluate and compare immediate bond failure, bond failure after 12 months, chair side 
time, plaque accumulation, wire breakage and post treatment relapse of the 3D metal printed 
mandibular retainer and conventional fixed metal retainer.  
Review of literature:  
Conventional Fixed Retention 
In 1973 Knierim introduced the direct bonded retainer14, which is still frequently used to 
prevent the relapse of crowding in the mandibular anterior region. In 1977, Zachrisson 
introduced the multistranded bonded lingual retainer, which, although varying in different 
shapes, has become the gold standard15. Various types of retainers have been described with 
wires of differing materials, properties and diameters, or using different types of composites 
for the adhesion or with fiber reinforcement. The primary problem of multi stranded lingual 
wires is their high failure rate. Studies indicate that 27.2% of bonded mandibular retainers and 
58.2% of bonded maxillary retainers fail during the retentive phase16. It has also been found 
that the plaque accumulation is more on the gingival aspect of the wire than on the incisal17. 
Ideally, fixed retainers should be flexible enough to allow some degree of physiologic 
movement of the retained teeth, hence, providing homeostasis to the periodontium as well as 
reducing tension within the composite bonding material18. However, multistranded wires are 
significantly more effective at maintaining incisor alignment19. Renkema et al. reported 90% 
of patients with a multistranded wire retainer to have perfect alignment of lower incisors after 
5 years of retention20. Patients with relapse experienced only 0.8 mm of relapse, on average. 
Later on, different designs and materials were introduced to overcome previously mentioned 
problems. There has been introduced fibreglass bonded to each tooth, using composite 
techniques, with acid etching of the enamel21. Although they were aesthetically acceptable and 
non-metallic, they showed a higher failure indicator in maintaining bonding to enamel, and 
their rigidity prevented physiological tooth mobility. Moreover, modified multi-loop fixed 
retainers were known as hygienic retainer due to their less damage to periodontal apparatus22.  
 
 

 
7 
3D Metal Printing of Fixed Retention Wire 
In recent years a new possibility is available for dental practitioners: CAD-CAM technology 
and 3D printing, which find their application in all aspects of orthodontics. Orthodontists are 
already familiar with several products that use 3D printers (i.e. invisible aligners), also known 
as additive manufacturing, 3D printing is a technology whereby sequential layers of material 
are layered on top of one another to form an object23. Two recent articles reported the 
fabrication of a custom lingual retainer cut from a nickel-titanium block with CAD/CAM 
technology and a CAD/CAM Zirconium bar as a bonded mandibular fixed retainer13,24 
In order to make a customized lingual retainer, a digital impression, generated by Intraoral 
Scanner, and its STL file are needed in the first place. Then the generated STL file will be 
elaborated by the software of the 3D printer and the final piece designed and printed. The 
main advantages to use digital impressions are essentially the higher comfort for the patient, 
the less working time needed, the relatively lower cost.  
CAD/CAM fixed retainers are considered a potential alternative to conventional multistranded 
wires, and are claimed to deliver utmost accuracy, and to reduce chair-time25. Furthermore, 
they seem to offer high predictability when limited bonding surface is available, as well as in 
anatomically demanding regions26. In addition, CAD/CAM fixed retainers might provide a 
very accurate passive fitting to the lingual tooth surface, which is critical as wire tension 
produced during bonding procedure can result in undesirable adverse effects over the long 
term, such as unexpected post-treatment tooth movements; unrelated to the initial 
malocclusion, caused by residual stress between the bonding points27. 
In 2012 Memotain—a new CAD/CAM fabricated lingual retainer wire made of custom-cut 
nickel-titanium was introduced as an alternative to multistranded lingual retainers. Memotain 
is a CAD/CAM fabricated lingual retainer made of 0.014 3 0.014-in rectangular nickel-
titanium28. The wire is highly flexible and custom cut to precisely adapt to the patient's lingual 
tooth anatomy. It was invented by an orthodontist, Pascal Schumacher. The name Memotain is 
a portmanteau from the combination of “memory” and “retainer” because of the uniqueness of 
using nickel-titanium for the lingual wire. Of particular interest is the potential for Memotain 
to provide minor tooth alignment. The idea of applying a nickel-titanium wire as an “active” 
lingual retainer was first reported by Liou et al in 200129. Memotain's precision fit and 
memory enable its use passively for tooth maintenance, as well as actively to retreat mild 
mandibular anterior crowding without the need for brackets. 
 
Explanation for choice of comparators:  
In the ongoing study, conventional metal mandibular fixed retainer will be the control group 
using multistrand dead soft stainless steel wire. Thus, a well-designed randomized clinical 
trial will be conducted to evaluate the immediate bond failure and bond failure during 12 
months of the 3D metal printed fixed retainer and conventional metal fixed retainer.  
 
 
 
 
 
 

 
8 
7. Objectives: 
Primary objective: 
To evaluate the immediate bond failure and bond failure during first 12 months after 
placement of 3D metal fixed retainer and conventional metal fixed retainer. 
Secondary objectives 
 To evaluate plaque accumulation after placement of each metal fixed retainer. 
 To evaluate chair side time of placement of each metal fixed retainer. 
 To evaluate wire breakage during 12 months of each fixed retainer. 
 To evaluate post treatment relapse of each fixed retainer 
  
PICOTs format:  
P: patient with the need of fixed bonded mandibular retainer after orthodontic treatment  
I: 3D printed perforated metal fixed retainer.  
C: conventional fixed bonded mandibular retainer  
O:  
 
Outcome Name 
Measuring Tool 
Measuring unit 
Primary 
Immediate 
Bond 
Failure 
Counting number of teeth 
debonded 
immediately 
after placement of wire 
Numerical 
Bond Failure during 
first 12 months 
Counting number of teeth 
debonded during first 12 
months of placement 
Numerical 
Secondary 
Chairside Time 
Digital stopwatch 
Seconds 
Wire Breakage 
Yes/No 
 
Plaque Accumulation 
Plaque Index 
Numerical 
Post treatment Relapse Little Irregularity Index 
Numerical 
T0: Immediate, T1: 3 month follow up, T2: 6 months, T3: 9 months and T4: 12 month follow 
up  
S: Randomized controlled clinical trial. 
 
Hypothesis:  
At the start of this study, it is assumed that there is no difference between 3D metal printed 
retainer and conventional metal fixed retainer regarding bond failure.              
 
8. Trial design: 
This trial is designed as an interventional, parallel, randomized, controlled trial with allocation 
ratio 1:1. It will be performed at Department of Orthodontics and Dentofacial Orthopedics 
outpatient clinic of the educational hospital of the Faculty of Dentistry, Cairo University. 
 
 
 
 
 

 
9 
III. Methods 
A) Participants, interventions & outcomes 
9. Study settings: 
 Source of patients: patients who finished their orthodontic treatment at the outpatient 
clinic of Orthodontic department, Faculty of Dentistry, Cairo University, Cairo 
government, Egypt. 
 Time: 2024-2025 The study will last for 12 months. 
 10. Eligibility criteria: 
All the recruited subjects will follow 
Inclusion criteria:  
1. Patients with properly finished orthodontic treatment. 
2. No sex predilection. 
3. The presence of 4 permanent mandibular incisors and 2 permanent mandibular canines. 
4. No active caries, restorations, fractures, or periodontal disease of previously mentioned 
teeth  
5. Patients with good oral hygiene. 
Exclusion criteria:   
1. Patients with no need of fixed mandibular retention. 
2. Enamel hypoplasia or hypocalcification of mandibular anterior teeth. 
3. Abnormal morphology of mandibular anterior teeth 
4. Periodontal disease that contraindicates fixed orthodontic retention. 
5. No or poor patient’s compliance & bad oral hygiene. 
6. Psychological problems. 
11. Interventions 
A) Treatment Group 
After finishing orthodontic treatment, mandibular metal fixed retention wire will be placed on 
lingual surface of mandibular anterior teeth for all patients. The key of modification is 
digitally designing fixed metal retainer which will be custom made for each patient, and 3D 
metal printing of the fixed retention wire using Riton Metal printer (Riton Additive 
Technology Company, China) instead of using generic metal wire for all patients. 
The sample selection and screening for inclusion of patients in clinical trial will be performed 
at clinic of Orthodontic department, Faculty of Dentistry, Cairo University. 
The following steps will be performed for each patient: 
Initial records: 
 Case History: Personal information, Medical & Dental History. 
 Study Model: An impression of upper & lower arches will be taken using condensation 
silicone elastomeric impression material in a metal tray with patient fully awake and 
without any anesthesia in a clinical setting.  
 Photographs: Standardized digital photographs (frontal, profile, oblique) will be taken 
with a Canon EOS 750D digital camera (Canon, Tokyo, Japan) for all patients. 
1. Scanning & designing fixed retention wire: 

 
10 
 The lower arches will be carefully scanned by intraoral 3D scanner of 3Shape Company 
(Copenhagen, Denmark) & 3D model will be used for making design of the metal fixed 
retention wire. 
2. Fabrication of fixed retention wire: 3D metal printing of fixed retention wire for 
patients of treatment group. Wires will be printed using 3d Printer Fast Speed Sls 
Metal Printer DUAL150 (Riton, China). The printer also allows the use of any kind of 
printing metal powder. 
3. Clinical application of fixed retention wire: 
 Teeth to be bonded are polished and etched.  
 Teeth isolation & moisture control are achieved. 
 Adhesive bond is applied to teeth (3M Unitek, Monrovia, California, USA) and light 
cured. 
 Placement of metal wire on prepared teeth carefully & ensure complete fitting of wire. 
 Start curing of flowable composite (3M Unitek, Monrovia, California, USA). 
 Chair side time will be recorded. 
 Number of teeth that will be debonded immediately after wire placement will be counted 
& recorded. 
4. 3 Months Follow up: Bond failure will be recorded every 3 months. 
5.  12 Months Follow up: Plaque index and Little irregularity index will be recorded 
together with bond failure or any wire breakage. 
 
B) Control Group 
 All patients of this group will follow same steps of fixed retention procedure as treatment 
group but the metal wire placed will be conventional fixed retention wire (Retainium, 
Reliance Orthodontics). 
 Chairside time will be recorded & number of debonded teeth after wire placement will be 
recorded.  
12. Outcomes: 
Primary outcomes: Immediate bond failure and bond failure during first 12 months after 
placement of 3D metal fixed retainer and conventional fixed metal retainer. 
Secondary outcomes: Chairside time, wire breakage, plaque accumulation and post treatment 
relapse of 3D metal printed fixed retainer and conventional fixed retainer. 
 
 
 
 
 
 
 
 
 

 
11 
13. Participant timeline 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
T1 
 
T2 
 
 
 
14. Sample size: 
Sample size calculated depending on a previous study30 (Nagani NI,  et al 2020) as 
reference. According to this study, the failure bond frequency in MSW was 31.41%.  while the 
bond failure in the other group was 5%, we will need to study 32 case in each group with 
probability (power) 0.8.   The Type I error probability is 0.05.  The chi-squared test was 
performed by P.S.Power 3.1.6.   
 
Total sample size = 32 per each group 
 
 
 
 
Patients Screening 
Randomization 
Treatment Group 
Control Group 
Taking another study models 
Evaluation of bond failure, wire breakage, plaque accumulation and post 
treatment relapse 
Initial records: Case History, Study Models, Intraoral & Extraoral Photographs & Scaling 
Intraoral Scanning of lower arches & making 
design of lower fixed retainer  
Counting number of teeth debonded 3 months after placement of wire 
3D metal printing of lower fixed retainer  
Recording plaque index &Bonding of fixed retention wires & Recording chairside time 
Counting number of teeth debonded immediately after placement of wire 

 
12 
15. Recruitment: 
 Patients will be selected from the outpatient clinic of the orthodontic Department – 
Cairo University 
 Consecutive sampling is done through screening of patients. This will continue until 
the target population is achieved. 
 Identifying and recruiting potential subjects is achieved through patient database. 
 
B) Assignment of interventions 
16. Allocation: 
16a. Randomization: 
It will be performed as 1:1 allocation. The sequence of the two groups (Conventional & 3D 
metal printed wires) will be done by computer generated random numbers. This will be done 
by using Microsoft Office Excel 2007 sheet. 
 
16b. Allocation concealment mechanism:  
Random numbers obtained by random sequence generation will be written on white papers, 
each paper will be kept in sealed envelope. Sealed envelopes will be kept in box at the 
secretary of orthodontic department office. 
 
16c. Implementation 
Implementation will be carried out in the secretary of the orthodontic department at the 
Faculty of Dentistry, Cairo University. 
 
17. Masking/blinding: 
 The statistician will not be blinded.   
 Assessor (other than the operator performing fixed retention) will carry out 
measurements blindly on study models. 
 Patients & Operator performing fixed retention will not be blinded as the operator 
knows the shape of the fixed retention wires. 
C) Data collection, management, and analysis: 
18. Data collection methods 
Bond Failure Outcomes: This will be assessed by counting the number of teeth debonded 
immediately after placement of wire and after 3, 6, 9 & 12 months. 
Chairside Outcomes:   This will be assessed via measuring chair side time of bonding fixed 
retention wire by digital stop watch, starting from etching of teeth ending up with complete 
curing of flowable composite balls. 
Plaque Accumulation Outcomes: This will be assessed via calculating score of plaque index 
before fixed retention wire placement and after its removal. 
Wire Breakage Outcomes: This will be assessed by reporting any wire breakage interdentally 
during 12 months follow up. 
Post Treatment Relapse Outcomes: This will be assessed by calculating little irregularity 
index before wire placement and during 12 months follow up. 

 
13 
19. Data management: 
All Data will be recorded, organized, tabulated and stored electronically in the computer and 
statistically analyzed. 
 
20. Statistical methods: 
Handling of numerical / quantitative variables: 
Numerical data will be explored for normality by checking the data distribution using 
Kolmogorov- Smirnov and Shapiro-Wilk tests. Data will be presented as mean & standard 
deviation. If data will be normally distributed comparison between 2 different groups will be 
performed by using Independent t-test, comparison between 2 related groups will be 
performed by using Paired t-test, while comparison between more than 2 groups will be 
performed by using One Way ANOVA test followed by Tukey`s Post Hoc test for multiple 
comparisons.  
If data will be non-parametric data comparison between 2 different groups will be 
performed by using Mann-Whitney test, comparison between 2 related groups will be 
performed by using Wilcoxon Signed Rank test, while comparison between more than 2 
groups will be performed by using Kruskal-Wallis test. 
Handling of categorial / qualitative variables: 
Data will be presented as frequency and percentages. All comparisons will be performed by 
using Chi square test. 
Statistical analysis: 
Data were collected, tabulated, and statistically analyzed using Microsoft Excel ® 
2016, Statistical Package for Social Science (SPSS)® Ver. 24. and Minitab ® statistical 
software Ver. 16.  
 
D) Data monitoring: 
21. Monitoring 
The results of the study will be monitored by Data Monitoring Committee that will be 
constituted o the trial’s supervisors (Dr. Khaled H and Dr. Amr B). Interim data will be 
presented periodically to the committee; the committee will advise the operator to pause the 
trial if the interim analysis showed that the patients are subjected to high risks due to the 
intervention. 
 
22. Harms 
If any harm happens to the patient before starting of treatment, it will be reported as unrelated. 
If it happens after, it will be recorded and reported. 
 
23. Audit 
In the present study, auditing will be done by the main and co-supervisors to assure quality of 
the research methods. 
 
 
 
 
 

 
14 
IV. Ethics and dissemination 
24. Research ethics approval 
This protocol will be reviewed, approved and agreed by CEBD [Center for Evidence Based 
Dentistry CU] Cairo University, Egypt and approved by ethical committees. 
 
25. Protocol amendments 
The Ethics Committee/IRB will be notified of any modifications of the protocol. 
 
26. Informed consent 
The trial will be explained to the patients and they will receive information sheets regarding 
main aspects of the trial. The principal investigator will obtain signed consent from the 
patients willing to participate in the trial. All information sheets and consent forms will be 
translated to Arabic. 
 
27. Confidentiality 
Personal information about participants will be acquired during the process of trial 
recruitment, eligibility screening, and data collection. All study related information will be 
stored securely at the study site. All participant information and data will be identified by a 
coded ID number just to keep the participant’s rights in confidentiality and will be stored in 
locked file cabinets in areas with limited access. Participants’ study information will not be 
released outside of the study without the written permission of the participant. 
 
28. Declaration of interest 
No Conflict of interests for the supervisors is present. There will be no declaration of interests 
for the supervisors and the principle operator.  
 
29. Access to data 
Only the supervisors and the principle operator will have access to study data. 
 
30. Post-trial care 
Patient follow up will be done during completion of orthodontic treatment in outpatient clinic 
of the orthodontic Department – Cairo University. 
 
31. Dissemination policy 
We are intending to disseminate the results of the trial in the library of the Faculty, in the 
Egyptian Dental Journal and in the Journals of Orthodontics. 
 
 
 
 
 

 
15 
V. Appendices 
32. Informed consent 
 
Human Subjects Application Form
 
   
 
Kindly fulfill the following: 
Research title:  Evaluation of 3D Printed Metal Fixed Mandibular Retainer versus 
Conventional Fixed Bonded Retainer: A Randomized Clinical Trial.  
Full name of the researcher(s): Mariam Alaa El-Din El-Sebaay 
Affiliation of the researcher(s): / 
Category of study:       Master        [     ]                  PHD/D       [  
   ]  
Others     [     ] 
Type of study design:    Randomized Clinical Trial 
Objective of the research: To evaluate immediate bond failure and bond failure after 
12 months of 3D printed metal fixed retainer. Moreover, to assess wire breakage, plaque 
accumulation, chair side time and post-treatment relapse of this novel 3D metal printed fixed 
retainer compared to conventional one. 
 
Steps of the research in short including the following: 
 Steps in short 
1. Patients Screening & Randomization. 
2. Scaling will be done to treatment and control groups 2 days before application of fixed 
retainers. 
3. Taking initial records for control & treatment groups: Case History, Study Models, 
Intraoral & Extraoral Photographs and Panoramic Radiograph. 
4. Scanning of lower arches & performing digital design of fixed retainer. 
5. 3D Metal printing of retainer for treatment group. 
6. Bonding of fixed retainer in patient’s mouth in treatment and control groups & 
Recording chairside time. 
7. Checking bond failure immediately following bonding of fixed retainer and after 3, 6 & 
9 months.  
8. After 12 months, assess bond failure, wire breakage, plaque accumulation and post 
treatment relapse. 
 Number of visits & follow up period     
1. First visit: taking records & scanning  
2. Second visit: bonding of fixed retention 
3. Third visit: after 12 months for assessment of plaque accumulation, wire breakage, 
bond failure and post treatment relapse. 
Direct benefit of the research to the human volunteer: Receiving suitable 
fixed orthodontic retention they need. 
The scientific interest and the desired public benefit of the research: 
1. Digital designing of fixed retention wire is expected to be more accurate as it will be 

 
16 
customized personally for the patient, thus, bond failure will be eliminated and 
therefore risk of relapse will be reduced. 
2. Perforated design of 3D metal printed fixed retainer is expected to decrease rate of 
bond failure on the long term, thus main problem of fixed retention will be solved. 
3. Metal printed fixed retention wire is expected to be more precise and accurate that 
conventional generic one. 
Side effects and the degree of risk and expected to occur and how to deal 
with them: Normal hazards of any orthodontic fixed retention as caries,and periodontal 
problems. Moreover, debonding of retainer may occur and if the patient did not fix it, relapse 
may occur. 
Patient's full knowledge of the research steps: Reading [ 
  ] Oral 
explanation [
  ] Other [  ] 
1. I have carefully reviewed and understood the purpose of conducting the research 
and the nature of this study, and I understand what is necessary to accomplish 
these procedures. 
2. The researcher has informed me of the possible therapeutic alternatives for this 
research. 
3. The researcher has informed me of all the possible risks of this research and how 
to deal with it. 
4. I agree to the imaging, recording, and all types of radiology to be performed in this 
study, on condition of anonymity. 
5. I have made an accurate report on my health history and informed the doctor of all 
kinds of health reactions or unusual allergies to medicines, food, insect bites, 
anesthetics, dust or any reactions that have occurred to me from any other 
substances, abnormal bleeding or any other related conditions for my health. 
6. I acknowledge that I am not involved in any other research from the beginning of 
this research until the end of this research and that I will inform the researcher if I 
enter any other research throughout the period of this research. 
7. I undertake to return the medical devices (instruments) used in the research in 
case of discontinuation or when the research is completed. 
After knowing the available information related to the research, the volunteer or 
the person in charge will be able to choose freely whether or not to subscribe. In 
case of approval, kindly fill out the data shown. The volunteer has the right to 
withdraw from the research without giving reasons anytime. 
  
The researcher in charge of the research undertakes to keep the information of 
the volunteer person confidential by participating in the research, stating the 
methods used, such as replacing names with code numbers or hiding facial 
features when photographing (etc.). 
                                                                                                                                   Signature:
                                                                                                                         Date: 
                                                   هذا البحث تمت موافقة اللجنه عليه برقم                                         
 
 
 
 

 
17 
 
33. Biological specimens 
Not applicable 
 
VI. Statement of originality 
34. Statement of originality 
 
The novelty of this research is based on applying 3D metal printing—a technique not yet 
utilized in the production of orthodontic retention wires. This method has the potential to 
transform the fabrication process, allowing for the creation of retention wires that are 
precisely customized to each patient while also enhancing mechanical properties and 
biocompatibility. 
The study seeks to overcome the limitations of traditional fixed retention wire, such as 
continuous bond failure, plaque accumulation, and long chairside time. The hypothesis is that 
3D-printed retention wires will provide retention stability and patient comfort better than 
existing methods. Thus, this research has the potential to redefine the approach to orthodontic 
retention, moving towards more efficient, customizable, and patient-specific solutions. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
18 
 
VII. References 
1- Sadowsky C, Schneider B J, BeGole E A, Tahir E. Long-term stability after orthodontic 
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Available from: http://dx.doi.org/10.1186/s12903-020-01167-7