xml: <clinical_study>
    <!-- This xml conforms to an XML Schema at:
      https://clinicaltrials.gov/ct2/html/images/info/public.xsd -->
    <required_header>
      <download_date>ClinicalTrials.gov processed this data on September 20, 2023</download_date>
      <link_text>Link to the current ClinicalTrials.gov record.</link_text>
      <url>https://clinicaltrials.gov/ct2/show/NCT05968625</url>
    </required_header>
    <id_info>
      <org_study_id>UNIVERSITI MALAYA</org_study_id>
      <secondary_id>UMG013E-2023</secondary_id>
      <nct_id>NCT05968625</nct_id>
    </id_info>
    <brief_title>3D-Printed Vs Thermoformed Retainers: Comparison of Post-Treatment Stability, Changes in Mechanical Properties and Patients' OHRQoL</brief_title>
    <official_title>Post-Treatment Stability, Changes in Mechanical Properties and Patients' OHRQoL Of Direct 3D-Printed Retainers Versus Thermoformed Retainers: An Open-label Randomized Controlled Trial</official_title>
    <sponsors>
      <lead_sponsor>
        <agency>University of Malaya</agency>
        <agency_class>Other</agency_class>
      </lead_sponsor>
    </sponsors>
    <source>University of Malaya</source>
    <oversight_info>
      <has_dmc>No</has_dmc>
      <is_fda_regulated_drug>No</is_fda_regulated_drug>
      <is_fda_regulated_device>No</is_fda_regulated_device>
    </oversight_info>
    <brief_summary>
      <textblock>
        Following completion of orthodontic treatment, prolonged retention with either part-time or&#xD;
        full-time wear of retainers is crucial in preventing relapse. Clear thermoformed retainers&#xD;
        (TFR) are easy to fabricate and popular among orthodontic patients. With the advent of&#xD;
        digital orthodontics and the development of biocompatible photopolymerizable resin, it is now&#xD;
        possible to fabricate direct 3D-printed retainers.&#xD;
  &#xD;
        The aim of this study is to determine and compare the post-treatment stability of dentition,&#xD;
        changes in thickness and mechanical properties of the retainers, and oral health-related&#xD;
        quality of life (OHRQoL) of patients wearing direct 3D-printed retainers and conventional&#xD;
        thermoformed retainers over a retention period of 6 months.&#xD;
      </textblock>
    </brief_summary>
    <detailed_description>
      <textblock>
        Primary Objective:&#xD;
  &#xD;
        1. To determine and compare the post-treatment stability for direct 3D printed retainers&#xD;
        (3DPR) and conventional TFR (TFR) at baseline (T0), 3 months (T1) and 6 months (T2).&#xD;
  &#xD;
        Secondary Objectives:&#xD;
  &#xD;
          1. To determine and compare the thickness and mechanical properties for 3DPR and TFR after&#xD;
             6 months of usage.&#xD;
  &#xD;
          2. To determine and compare the OHRQoL of patients wearing 3DPR and TFR at T0, T1 and T2.&#xD;
  &#xD;
        Sample size calculation:&#xD;
  &#xD;
        Sample size calculation is based on the study done by Kumar &amp; Bansal (2011) which compared&#xD;
        the effectiveness of two different removable retainers on stability. With an effect size of&#xD;
        1.127, α = 0.05, and power = 0.80. Using G*Power version 3.1.9.7 software, the total number&#xD;
        of samples is n = 22 (11 subject per group). This number is increased by 30% to account for&#xD;
        the dropout rate to produce the final sample size, n = 30 (15 subjects per group).&#xD;
  &#xD;
        Methodology:&#xD;
  &#xD;
        Subjects who have completed their orthodontic treatment (fulfil the inclusion and exclusion&#xD;
        criteria) and are ready for debond, will be invited to participate in the research and&#xD;
        consecutively recruited, between April 2023 until September 2023, in the Postgraduate&#xD;
        Orthodontic Clinic, Dental Specialists and Research Tower, Faculty of Dentistry, Universiti&#xD;
        Malaya, Malaysia. Patient information sheets and consent forms will be issued to the subjects&#xD;
        that fulfil the criteria. Only consented respondents will be recruited.&#xD;
  &#xD;
        All 30 subjects will be randomly allocated (simple randomization with 1:1 allocation) to&#xD;
        either the TFR group or the 3DPR group by using number generated list provided by&#xD;
        www.random.org . The randomization will be performed by the main supervisor, who is not&#xD;
        involve in the treatment, data collection and data analysis of the research. The operator&#xD;
        will be concealed from the group allocation. The allocation will be revealed to the operator&#xD;
        on the day of debond appointment with a opaque white envelope.&#xD;
  &#xD;
        All the subjects will undergo the same standard debond process. and receive a post debond&#xD;
        thermoformed retainers within 24 hours which they are required to part-time for every night&#xD;
        (8-12 hours).&#xD;
  &#xD;
        The subjects will be reviewed after 1 week (T0) for scanning of teeth with Trios 3 intraoral&#xD;
        scanner. The interventional retainers (TFR or 3DPR) will be issued after 2 weeks. The&#xD;
        subjects are instructed to wear the retainers part-time (8-12 hours) for every nights. A&#xD;
        pamphlet that contains detailed information on the care of retainers will also be provided to&#xD;
        every subject. All the subjects will be reviewed after 3 months (T1) and at 6 months (T2)&#xD;
        after wearing the interventional retainers.&#xD;
  &#xD;
        The primary outcome is to assess the post-treatment stability after part time wear of the&#xD;
        retainers for a period of 6 months. The subject's upper and lower dentition will be scanned&#xD;
        by using intraoral scanner at T0, T1, and T2. The measurements will be performed digitally&#xD;
        using 3Shape orthodontic analyzer software. Overjet, overbite, intermolar width, and little&#xD;
        irregularity index will be measured.&#xD;
  &#xD;
        OHIP-14 questionnaire will be given to the participants to answer during T0, T1 and T2. All&#xD;
        the retainers will be retrieved at T2 to undergo mechanical test.&#xD;
  &#xD;
        Statistical Analysis:&#xD;
  &#xD;
        The data collected will be entered into SPSS software (version 26.0). i. Chi-square tests&#xD;
        will be used to compare baseline characteristics between the 2 groups.&#xD;
  &#xD;
        ii. Repeated measures ANOVA or paired t-test will be used to determine the mean differences&#xD;
        in post treatment stability, thickness of retainers, mechanical properties of retainers and&#xD;
        OHIP-14 scores at different time intervals. The p-value will be set to less than 0.05.&#xD;
  &#xD;
        iii. Two samples independent t test will be used to compare the post-treatment stability,&#xD;
        changes in thickness, mechanical properties, and OHIP-14 scores between TFR and 3DPR group.&#xD;
        The p-value will be set to less than 0.05.&#xD;
  &#xD;
        iv. Shapiro-Wilk tests will be referred, and non-parametric tests will be performed for&#xD;
        skewed data.&#xD;
  &#xD;
        Data will be analyzed following the intention-to-treat analysis.&#xD;
      </textblock>
    </detailed_description>
    <overall_status>Recruiting</overall_status>
    <start_date type="Actual">March 28, 2023</start_date>
    <completion_date type="Anticipated">October 2024</completion_date>
    <primary_completion_date type="Anticipated">May 2024</primary_completion_date>
    <phase>N/A</phase>
    <study_type>Interventional</study_type>
    <has_expanded_access>No</has_expanded_access>
    <study_design_info>
      <allocation>Randomized</allocation>
      <intervention_model>Parallel Assignment</intervention_model>
      <intervention_model_description>Direct 3D-printed retainers</intervention_model_description>
      <primary_purpose>Screening</primary_purpose>
      <masking>Single (Outcomes Assessor)</masking>
      <masking_description>This is a single-blinded study, where the statistician that analyzes the data is blinded. The subjects are impossible to blind due to subtle differences in the physical appearance of both appliances.&#xD;
  Blinding of the operator will not be possible due to the differences in clinical procedures involved in fabrication of TFR and 3DPR.</masking_description>
    </study_design_info>
    <primary_outcome>
      <measure>Post-treatment stability</measure>
      <time_frame>6 months</time_frame>
      <description>The subject's upper and lower dentition will be scanned by using intraoral scanner at T0, T1, and T2. The measurements will be performed digitally using 3Shape orthodontic Analyzer software (3Shape A/S, Copenhagen, Denmark). Measurements: Overjet (mm), Overbite (mm), Intermolar width (mm), and little irregularity index (mm). All the measurements are in millimetres.</description>
    </primary_outcome>
    <secondary_outcome>
      <measure>Changes in thickness of retainers</measure>
      <time_frame>6 months</time_frame>
      <description>Measurements of changes in thickness (mm) will be performed by the principal investigator by using an electronic digital thickness gauge with a resolution of 0.01 mm and accuracy of ±0.02 mm, which will be calibrated before each use.</description>
    </secondary_outcome>
    <secondary_outcome>
      <measure>Changes in hardness of retainers</measure>
      <time_frame>6 months</time_frame>
      <description>The extra sets of retainers (5 sets from each group) at T0 and the retrieved retainers (5 sets from each group) at T2 of each group will be tested. The hardness that will be determined is Vickers hardness in Megapascal (MPa). A universal hardness testing machine (DUH-211S, Shimadzu, Kyoto Japan) will be used to determine the hardness.</description>
    </secondary_outcome>
    <secondary_outcome>
      <measure>Oral Health Impact Profile -14 (OHIP-14)</measure>
      <time_frame>6 months</time_frame>
      <description>This research will use the validated Modified short version of the OHIP-14 for Malaysian adults with questions that are relevant to subjects wearing removable retainers. Responses to each item will be scored on a five-point Likert scale measuring from never (score 0) to very often (score 4). The OHIP-14 questionnaire will be given to the participants to answer during T0, T1 and T2.</description>
    </secondary_outcome>
    <number_of_arms>2</number_of_arms>
    <enrollment type="Anticipated">30</enrollment>
    <condition>Orthodontic Retention</condition>
    <arm_group>
      <arm_group_label>Thermoformed retainers (TFR)</arm_group_label>
      <arm_group_type>Experimental</arm_group_type>
      <description>Thermoformed retainers are constructed from an Erkodur blank (ERKODENT® Erich Kopp GmbH, Pfalzgrafenweiler, Germany) with 1.0 mm in thickness, following the manufacturer's instructions.</description>
    </arm_group>
    <arm_group>
      <arm_group_label>Direct 3-D printed retainers (3DPR)</arm_group_label>
      <arm_group_type>Experimental</arm_group_type>
      <description>Private dental laboratories directly print the retainers using a NextDent 3D printer and NextDent ortho Flex resin. Thickness of 0.80mm</description>
    </arm_group>
    <intervention>
      <intervention_type>Device</intervention_type>
      <intervention_name>Thermoformed retainers</intervention_name>
      <description>conventional thermoformed retainers fabricated on stone models.</description>
      <arm_group_label>Thermoformed retainers (TFR)</arm_group_label>
    </intervention>
    <intervention>
      <intervention_type>Device</intervention_type>
      <intervention_name>3D-printed retainers</intervention_name>
      <description>3D-printed retainers fabricated directly by DLP printer.</description>
      <arm_group_label>Direct 3-D printed retainers (3DPR)</arm_group_label>
    </intervention>
    <eligibility>
      <criteria>
        <textblock>
          Inclusion Criteria:&#xD;
  &#xD;
            -  Fixed appliance treatment in both arches and indicated for VFR in the retention phase&#xD;
               as part of their original treatment plan.&#xD;
  &#xD;
            -  No intention to relocate within the study period; able to attend the three-monthly&#xD;
               review appointments for half a year.&#xD;
  &#xD;
          Exclusion Criteria:&#xD;
  &#xD;
            -  Single-arch or sectional fixed appliances.&#xD;
  &#xD;
            -  Space dentition.&#xD;
  &#xD;
            -  Hypodontia requiring tooth replacement on the retainer as a temporary measure.&#xD;
  &#xD;
            -  Previous treatment with maxillary expansion.&#xD;
  &#xD;
            -  Indicated for fixed retainer or double retention regime (such as VFRs fitted over&#xD;
               fixed retainers).&#xD;
  &#xD;
            -  Premature debond from the original fixed appliances course.&#xD;
  &#xD;
            -  Cleft lip and/or palate; or orthognathic cases.&#xD;
  &#xD;
            -  Learning difficulties and inability to read written instructions/ questionnaire in&#xD;
               English or Malay&#xD;
        </textblock>
      </criteria>
      <gender>All</gender>
      <minimum_age>18 Years</minimum_age>
      <maximum_age>N/A</maximum_age>
      <healthy_volunteers>Accepts Healthy Volunteers</healthy_volunteers>
    </eligibility>
    <overall_official>
      <last_name>Associate Professor Dr. Saritha Sivarajan</last_name>
      <role>Study Director</role>
      <affiliation>Faculty of Dentistry, Universiti Malaya</affiliation>
    </overall_official>
    <overall_contact>
      <last_name>Dr. Boo Hui Shan</last_name>
      <phone>+60102705306</phone>
      <email>17080312@siswa.um.edu.my</email>
    </overall_contact>
    <overall_contact_backup>
      <last_name>Associate Professor Dr. Saritha Sivarajan</last_name>
      <phone>+6037967 4802</phone>
      <phone_ext>4562</phone_ext>
      <email>saritha@um.edu.my</email>
    </overall_contact_backup>
    <location>
      <facility>
        <name>Orthodontic Postgraduate Clinic, Faculty of Dentistry, Universiti Malaya.</name>
        <address>
          <city>Kuala Lumpur</city>
          <state>Wilayah Persekutuan</state>
          <zip>50603</zip>
          <country>Malaysia</country>
        </address>
      </facility>
      <status>Recruiting</status>
      <contact>
        <last_name>Dr. Boo Hui Shan</last_name>
        <phone>+60102705306</phone>
        <email>17080312@siswa.um.edu.my</email>
      </contact>
      <contact_backup>
        <last_name>Associate Professor Dr. Saritha Sivarajan</last_name>
        <phone>+60379674802</phone>
        <phone_ext>4562</phone_ext>
        <email>saritha@um.edu.my</email>
      </contact_backup>
    </location>
    <location_countries>
      <country>Malaysia</country>
    </location_countries>
    <reference>
      <citation>Williams A, Bencharit S, Yang IH, Stilianoudakis SC, Carrico CK, Tufekci E. Effect of print angulation on the accuracy and precision of 3D-printed orthodontic retainers. Am J Orthod Dentofacial Orthop. 2022 Jan;161(1):133-139. doi: 10.1016/j.ajodo.2021.01.020.</citation>
      <PMID>35012743</PMID>
    </reference>
    <reference>
      <citation>Rowland H, Hichens L, Williams A, Hills D, Killingback N, Ewings P, Clark S, Ireland AJ, Sandy JR. The effectiveness of Hawley and vacuum-formed retainers: a single-center randomized controlled trial. Am J Orthod Dentofacial Orthop. 2007 Dec;132(6):730-7. doi: 10.1016/j.ajodo.2006.06.019.</citation>
      <PMID>18068589</PMID>
    </reference>
    <reference>
      <citation>Naeem OA, Bencharit S, Yang IH, Stilianoudakis SC, Carrico C, Tufekci E. Comparison of 3-dimensional printing technologies on the precision, trueness, and accuracy of printed retainers. Am J Orthod Dentofacial Orthop. 2022 Apr;161(4):582-591. doi: 10.1016/j.ajodo.2021.03.016.</citation>
      <PMID>35337648</PMID>
    </reference>
    <reference>
      <citation>Kumar AG, Bansal A. Effectiveness and acceptability of Essix and Begg retainers: a prospective study. Aust Orthod J. 2011 May;27(1):52-6.</citation>
      <PMID>21696115</PMID>
    </reference>
    <reference>
      <citation>Kessler A, Hickel R, Reymus M. 3D Printing in Dentistry-State of the Art. Oper Dent. 2020 Jan/Feb;45(1):30-40. doi: 10.2341/18-229-L. Epub 2019 Jun 7.</citation>
      <PMID>31172871</PMID>
    </reference>
    <reference>
      <citation>Jindal P, Juneja M, Siena FL, Bajaj D, Breedon P. Mechanical and geometric properties of thermoformed and 3D printed clear dental aligners. Am J Orthod Dentofacial Orthop. 2019 Nov;156(5):694-701. doi: 10.1016/j.ajodo.2019.05.012.</citation>
      <PMID>31677678</PMID>
    </reference>
    <reference>
      <citation>Etemad-Shahidi Y, Qallandar OB, Evenden J, Alifui-Segbaya F, Ahmed KE. Accuracy of 3-Dimensionally Printed Full-Arch Dental Models: A Systematic Review. J Clin Med. 2020 Oct 20;9(10):3357. doi: 10.3390/jcm9103357.</citation>
      <PMID>33092047</PMID>
    </reference>
    <reference>
      <citation>Cousley RR. Introducing 3D printing in your orthodontic practice. J Orthod. 2020 Sep;47(3):265-272. doi: 10.1177/1465312520936704. Epub 2020 Jul 6.</citation>
      <PMID>32627658</PMID>
    </reference>
    <reference>
      <citation>Cole D, Bencharit S, Carrico CK, Arias A, Tufekci E. Evaluation of fit for 3D-printed retainers compared with thermoform retainers. Am J Orthod Dentofacial Orthop. 2019 Apr;155(4):592-599. doi: 10.1016/j.ajodo.2018.09.011.</citation>
      <PMID>30935614</PMID>
    </reference>
    <reference>
      <citation>Can E, Panayi N, Polychronis G, Papageorgiou SN, Zinelis S, Eliades G, Eliades T. In-house 3D-printed aligners: effect of in vivo ageing on mechanical properties. Eur J Orthod. 2022 Jan 25;44(1):51-55. doi: 10.1093/ejo/cjab022.</citation>
      <PMID>33950232</PMID>
    </reference>
    <reference>
      <citation>Al-Moghrabi D, Salazar FC, Pandis N, Fleming PS. Compliance with removable orthodontic appliances and adjuncts: A systematic review and meta-analysis. Am J Orthod Dentofacial Orthop. 2017 Jul;152(1):17-32. doi: 10.1016/j.ajodo.2017.03.019.</citation>
      <PMID>28651764</PMID>
    </reference>
    <reference>
      <citation>Al-Moghrabi D, Littlewood SJ, Fleming PS. Orthodontic retention protocols: an evidence-based overview. Br Dent J. 2021 Jun;230(11):770-776. doi: 10.1038/s41415-021-2954-7. Epub 2021 Jun 11.</citation>
      <PMID>34117437</PMID>
    </reference>
    <reference>
      <citation>Thickett E, Power S. A randomized clinical trial of thermoplastic retainer wear. Eur J Orthod. 2010 Feb;32(1):1-5. doi: 10.1093/ejo/cjp061. Epub 2009 Oct 14.</citation>
      <PMID>19828592</PMID>
    </reference>
    <reference>
      <citation>Saub R, Locker D, Allison P. Derivation and validation of the short version of the Malaysian Oral Health Impact Profile. Community Dent Oral Epidemiol. 2005 Oct;33(5):378-83. doi: 10.1111/j.1600-0528.2005.00242.x.</citation>
      <PMID>16128798</PMID>
    </reference>
    <reference>
      <citation>Mohd Tahir N, Wan Hassan WN, Saub R. Comparing retainers constructed on conventional stone models and on 3D printed models: a randomized crossover clinical study. Eur J Orthod. 2019 Aug 8;41(4):370-380. doi: 10.1093/ejo/cjy063.</citation>
      <PMID>30321319</PMID>
    </reference>
    <verification_date>September 2023</verification_date>
    <study_first_submitted>July 17, 2023</study_first_submitted>
    <study_first_submitted_qc>July 26, 2023</study_first_submitted_qc>
    <study_first_posted type="Actual">August 1, 2023</study_first_posted>
    <last_update_submitted>September 5, 2023</last_update_submitted>
    <last_update_submitted_qc>September 5, 2023</last_update_submitted_qc>
    <last_update_posted type="Actual">September 8, 2023</last_update_posted>
    <responsible_party>
      <responsible_party_type>Principal Investigator</responsible_party_type>
      <investigator_affiliation>University of Malaya</investigator_affiliation>
      <investigator_full_name>DR BOO HUI SHAN</investigator_full_name>
      <investigator_title>Principle Investigator, Doctorate (Orthodontics) Postgraduate Student</investigator_title>
    </responsible_party>
    <keyword>Thermoformed retainers</keyword>
    <keyword>3D-printed retainers</keyword>
    <keyword>vacuum-formed retainers</keyword>
    <keyword>Post-treatment stability</keyword>
    <keyword>Orthodontics</keyword>
    <patient_data>
      <sharing_ipd>No</sharing_ipd>
    </patient_data>
    <!-- Results have not yet been posted for this study                                          -->
  </clinical_study>
  
  
text: download date: ClinicalTrials.gov processed this data on September 20, 2023
  link text: Link to the current ClinicalTrials.gov record.
  url: https://clinicaltrials.gov/ct2/show/NCT05968625
  org study id: UNIVERSITI MALAYA
  secondary id: UMG013E-2023
  nct id: NCT05968625
  lead sponsor: 
  has dmc: No
  is fda regulated drug: No
  is fda regulated device: No
  Following completion of orthodontic treatment, prolonged retention with either part-time or
        full-time wear of retainers is crucial in preventing relapse. Clear thermoformed retainers
        (TFR) are easy to fabricate and popular among orthodontic patients. With the advent of
        digital orthodontics and the development of biocompatible photopolymerizable resin, it is now
        possible to fabricate direct 3D-printed retainers.
  
        The aim of this study is to determine and compare the post-treatment stability of dentition,
        changes in thickness and mechanical properties of the retainers, and oral health-related
        quality of life (OHRQoL) of patients wearing direct 3D-printed retainers and conventional
        thermoformed retainers over a retention period of 6 months.
  Primary Objective:
  
        1. To determine and compare the post-treatment stability for direct 3D printed retainers
        (3DPR) and conventional TFR (TFR) at baseline (T0), 3 months (T1) and 6 months (T2).
  
        Secondary Objectives:
  
          1. To determine and compare the thickness and mechanical properties for 3DPR and TFR after
             6 months of usage.
  
          2. To determine and compare the OHRQoL of patients wearing 3DPR and TFR at T0, T1 and T2.
  
        Sample size calculation:
  
        Sample size calculation is based on the study done by Kumar & Bansal (2011) which compared
        the effectiveness of two different removable retainers on stability. With an effect size of
        1.127, α = 0.05, and power = 0.80. Using G*Power version 3.1.9.7 software, the total number
        of samples is n = 22 (11 subject per group). This number is increased by 30% to account for
        the dropout rate to produce the final sample size, n = 30 (15 subjects per group).
  
        Methodology:
  
        Subjects who have completed their orthodontic treatment (fulfil the inclusion and exclusion
        criteria) and are ready for debond, will be invited to participate in the research and
        consecutively recruited, between April 2023 until September 2023, in the Postgraduate
        Orthodontic Clinic, Dental Specialists and Research Tower, Faculty of Dentistry, Universiti
        Malaya, Malaysia. Patient information sheets and consent forms will be issued to the subjects
        that fulfil the criteria. Only consented respondents will be recruited.
  
        All 30 subjects will be randomly allocated (simple randomization with 1:1 allocation) to
        either the TFR group or the 3DPR group by using number generated list provided by
        www.random.org . The randomization will be performed by the main supervisor, who is not
        involve in the treatment, data collection and data analysis of the research. The operator
        will be concealed from the group allocation. The allocation will be revealed to the operator
        on the day of debond appointment with a opaque white envelope.
  
        All the subjects will undergo the same standard debond process. and receive a post debond
        thermoformed retainers within 24 hours which they are required to part-time for every night
        (8-12 hours).
  
        The subjects will be reviewed after 1 week (T0) for scanning of teeth with Trios 3 intraoral
        scanner. The interventional retainers (TFR or 3DPR) will be issued after 2 weeks. The
        subjects are instructed to wear the retainers part-time (8-12 hours) for every nights. A
        pamphlet that contains detailed information on the care of retainers will also be provided to
        every subject. All the subjects will be reviewed after 3 months (T1) and at 6 months (T2)
        after wearing the interventional retainers.
  
        The primary outcome is to assess the post-treatment stability after part time wear of the
        retainers for a period of 6 months. The subject's upper and lower dentition will be scanned
        by using intraoral scanner at T0, T1, and T2. The measurements will be performed digitally
        using 3Shape orthodontic analyzer software. Overjet, overbite, intermolar width, and little
        irregularity index will be measured.
  
        OHIP-14 questionnaire will be given to the participants to answer during T0, T1 and T2. All
        the retainers will be retrieved at T2 to undergo mechanical test.
  
        Statistical Analysis:
  
        The data collected will be entered into SPSS software (version 26.0). i. Chi-square tests
        will be used to compare baseline characteristics between the 2 groups.
  
        ii. Repeated measures ANOVA or paired t-test will be used to determine the mean differences
        in post treatment stability, thickness of retainers, mechanical properties of retainers and
        OHIP-14 scores at different time intervals. The p-value will be set to less than 0.05.
  
        iii. Two samples independent t test will be used to compare the post-treatment stability,
        changes in thickness, mechanical properties, and OHIP-14 scores between TFR and 3DPR group.
        The p-value will be set to less than 0.05.
  
        iv. Shapiro-Wilk tests will be referred, and non-parametric tests will be performed for
        skewed data.
  
        Data will be analyzed following the intention-to-treat analysis.
  allocation: Randomized
  intervention model: Parallel Assignment
  intervention model description: Direct 3D-printed retainers
  primary purpose: Screening
  masking: Single (Outcomes Assessor)
  masking description: This is a single-blinded study, where the statistician that analyzes the data is blinded. The subjects are impossible to blind due to subtle differences in the physical appearance of both appliances.
  Blinding of the operator will not be possible due to the differences in clinical procedures involved in fabrication of TFR and 3DPR.
  measure: Post-treatment stability
  time frame: 6 months
  description: The subject's upper and lower dentition will be scanned by using intraoral scanner at T0, T1, and T2. The measurements will be performed digitally using 3Shape orthodontic Analyzer software (3Shape A/S, Copenhagen, Denmark). Measurements: Overjet (mm), Overbite (mm), Intermolar width (mm), and little irregularity index (mm). All the measurements are in millimetres.
  measure: Changes in thickness of retainers
  time frame: 6 months
  description: Measurements of changes in thickness (mm) will be performed by the principal investigator by using an electronic digital thickness gauge with a resolution of 0.01 mm and accuracy of ±0.02 mm, which will be calibrated before each use.
  measure: Changes in hardness of retainers
  time frame: 6 months
  description: The extra sets of retainers (5 sets from each group) at T0 and the retrieved retainers (5 sets from each group) at T2 of each group will be tested. The hardness that will be determined is Vickers hardness in Megapascal (MPa). A universal hardness testing machine (DUH-211S, Shimadzu, Kyoto Japan) will be used to determine the hardness.
  measure: Oral Health Impact Profile -14 (OHIP-14)
  time frame: 6 months
  description: This research will use the validated Modified short version of the OHIP-14 for Malaysian adults with questions that are relevant to subjects wearing removable retainers. Responses to each item will be scored on a five-point Likert scale measuring from never (score 0) to very often (score 4). The OHIP-14 questionnaire will be given to the participants to answer during T0, T1 and T2.
  arm group label: Thermoformed retainers (TFR)
  arm group type: Experimental
  description: Thermoformed retainers are constructed from an Erkodur blank (ERKODENT® Erich Kopp GmbH, Pfalzgrafenweiler, Germany) with 1.0 mm in thickness, following the manufacturer's instructions.
  arm group label: Direct 3-D printed retainers (3DPR)
  arm group type: Experimental
  description: Private dental laboratories directly print the retainers using a NextDent 3D printer and NextDent ortho Flex resin. Thickness of 0.80mm
  intervention type: Device
  intervention name: Thermoformed retainers
  description: conventional thermoformed retainers fabricated on stone models.
  arm group label: Thermoformed retainers (TFR)
  intervention type: Device
  intervention name: 3D-printed retainers
  description: 3D-printed retainers fabricated directly by DLP printer.
  arm group label: Direct 3-D printed retainers (3DPR)
  criteria: 
  gender: All
  minimum age: 18 Years
  maximum age: N/A
  healthy volunteers: Accepts Healthy Volunteers
  last name: Associate Professor Dr. Saritha Sivarajan
  role: Study Director
  affiliation: Faculty of Dentistry, Universiti Malaya
  last name: Dr. Boo Hui Shan
  phone: +60102705306
  email: 17080312@siswa.um.edu.my
  last name: Associate Professor Dr. Saritha Sivarajan
  phone: +6037967 4802
  phone ext: 4562
  email: saritha@um.edu.my
  facility: 
  status: Recruiting
  contact: 
  contact backup: 
  country: Malaysia
  citation: Williams A, Bencharit S, Yang IH, Stilianoudakis SC, Carrico CK, Tufekci E. Effect of print angulation on the accuracy and precision of 3D-printed orthodontic retainers. Am J Orthod Dentofacial Orthop. 2022 Jan;161(1):133-139. doi: 10.1016/j.ajodo.2021.01.020.
  PMID: 35012743
  citation: Rowland H, Hichens L, Williams A, Hills D, Killingback N, Ewings P, Clark S, Ireland AJ, Sandy JR. The effectiveness of Hawley and vacuum-formed retainers: a single-center randomized controlled trial. Am J Orthod Dentofacial Orthop. 2007 Dec;132(6):730-7. doi: 10.1016/j.ajodo.2006.06.019.
  PMID: 18068589
  citation: Naeem OA, Bencharit S, Yang IH, Stilianoudakis SC, Carrico C, Tufekci E. Comparison of 3-dimensional printing technologies on the precision, trueness, and accuracy of printed retainers. Am J Orthod Dentofacial Orthop. 2022 Apr;161(4):582-591. doi: 10.1016/j.ajodo.2021.03.016.
  PMID: 35337648
  citation: Kumar AG, Bansal A. Effectiveness and acceptability of Essix and Begg retainers: a prospective study. Aust Orthod J. 2011 May;27(1):52-6.
  PMID: 21696115
  citation: Kessler A, Hickel R, Reymus M. 3D Printing in Dentistry-State of the Art. Oper Dent. 2020 Jan/Feb;45(1):30-40. doi: 10.2341/18-229-L. Epub 2019 Jun 7.
  PMID: 31172871
  citation: Jindal P, Juneja M, Siena FL, Bajaj D, Breedon P. Mechanical and geometric properties of thermoformed and 3D printed clear dental aligners. Am J Orthod Dentofacial Orthop. 2019 Nov;156(5):694-701. doi: 10.1016/j.ajodo.2019.05.012.
  PMID: 31677678
  citation: Etemad-Shahidi Y, Qallandar OB, Evenden J, Alifui-Segbaya F, Ahmed KE. Accuracy of 3-Dimensionally Printed Full-Arch Dental Models: A Systematic Review. J Clin Med. 2020 Oct 20;9(10):3357. doi: 10.3390/jcm9103357.
  PMID: 33092047
  citation: Cousley RR. Introducing 3D printing in your orthodontic practice. J Orthod. 2020 Sep;47(3):265-272. doi: 10.1177/1465312520936704. Epub 2020 Jul 6.
  PMID: 32627658
  citation: Cole D, Bencharit S, Carrico CK, Arias A, Tufekci E. Evaluation of fit for 3D-printed retainers compared with thermoform retainers. Am J Orthod Dentofacial Orthop. 2019 Apr;155(4):592-599. doi: 10.1016/j.ajodo.2018.09.011.
  PMID: 30935614
  citation: Can E, Panayi N, Polychronis G, Papageorgiou SN, Zinelis S, Eliades G, Eliades T. In-house 3D-printed aligners: effect of in vivo ageing on mechanical properties. Eur J Orthod. 2022 Jan 25;44(1):51-55. doi: 10.1093/ejo/cjab022.
  PMID: 33950232
  citation: Al-Moghrabi D, Salazar FC, Pandis N, Fleming PS. Compliance with removable orthodontic appliances and adjuncts: A systematic review and meta-analysis. Am J Orthod Dentofacial Orthop. 2017 Jul;152(1):17-32. doi: 10.1016/j.ajodo.2017.03.019.
  PMID: 28651764
  citation: Al-Moghrabi D, Littlewood SJ, Fleming PS. Orthodontic retention protocols: an evidence-based overview. Br Dent J. 2021 Jun;230(11):770-776. doi: 10.1038/s41415-021-2954-7. Epub 2021 Jun 11.
  PMID: 34117437
  citation: Thickett E, Power S. A randomized clinical trial of thermoplastic retainer wear. Eur J Orthod. 2010 Feb;32(1):1-5. doi: 10.1093/ejo/cjp061. Epub 2009 Oct 14.
  PMID: 19828592
  citation: Saub R, Locker D, Allison P. Derivation and validation of the short version of the Malaysian Oral Health Impact Profile. Community Dent Oral Epidemiol. 2005 Oct;33(5):378-83. doi: 10.1111/j.1600-0528.2005.00242.x.
  PMID: 16128798
  citation: Mohd Tahir N, Wan Hassan WN, Saub R. Comparing retainers constructed on conventional stone models and on 3D printed models: a randomized crossover clinical study. Eur J Orthod. 2019 Aug 8;41(4):370-380. doi: 10.1093/ejo/cjy063.
  PMID: 30321319
  responsible party type: Principal Investigator
  investigator affiliation: University of Malaya
  investigator full name: DR BOO HUI SHAN
  investigator title: Principle Investigator, Doctorate (Orthodontics) Postgraduate Student
  sharing ipd: No