Comparison of Patient-Reported Comfort Between Two Clear Aligner Trimming-Line Designs: A Split-Mouth Study (COMFORT-ALIGN)
20 augustus 2026 bijgewerkt door: Emilia Rusu, George Emil Palade University of Medicine, Pharmacy, Sciences and Technology of Targu Mures
Comparison of Patient-Reported Comfort Between Supragingival and Juxtagingival Clear Aligner Trimming-Line Designs: A Cross-Sectional, Within-Subject Split-Mouth Study
- The trimming-line design of clear aligners (supragingival versus juxtagingival) is a routine clinical decision whose influence on patient-reported comfort has not been established; available evidence on aligner comfort derives almost exclusively from comparisons with fixed appliances.
- This observational, cross-sectional study compares two clear aligner trimming-line designs with respect to patient-reported comfort: a supragingival design, whose edge rests on the marginal gingiva, and a juxtagingival design, whose edge follows the gingival contour without covering it. Because the two designs sit differently against the gingival soft tissue, they may be experienced differently during wear.
- Participants are patients already wearing one trimming-line design on one dental arch and the other on the contralateral arch; each participant thus serves as their own control. After a minimum of four weeks of wear, participants complete a 20-item questionnaire once, rating the frequency of defined oral experiences for the maxillary and mandibular arch separately on a three-point ordinal scale (0 = none, 1 = occasional, 2 = frequent).
- The questionnaire is anonymous; the design worn on each arch is identified from which of two identical forms a participant completes. Responses for the two designs are compared within each participant. The study evaluates whether trimming-line design is associated with differences in patient-reported comfort.
Studie Overzicht
Toestand
Voltooid
Interventie / Behandeling
Gedetailleerde beschrijving
- BACKGROUND AND RATIONALE
- Clear aligner therapy is an established modality in contemporary orthodontics. At the gingival margin, aligners are commonly trimmed according to one of two trimming-line designs, supragingival or juxtagingival. While the biomechanical and periodontal implications of trimming-line geometry have received attention, its influence on patient-reported outcomes remains uncharacterized. Available evidence on the comfort and oral health-related quality of life associated with aligner therapy derives predominantly from comparisons between aligners and fixed appliances, rather than from comparisons among aligner design parameters. The present study was designed to address this gap by evaluating whether trimming-line design is associated with differences in patient-reported comfort.
- THE TWO TRIMMING-LINE DESIGNS
- The supragingival design presents a straight marginal edge extending approximately 2 mm onto the marginal gingiva, in contact with the gingival surface without entering the gingival sulcus. The juxtagingival (festooned) design follows the scalloped contour of the gingival margin and terminates at the free gingival margin without overlying the gingiva. Both designs are fabricated from the same tri-layer thermoplastic aligner material (CA Pro, SCHEU-DENTAL GmbH, Iserlohn, Germany; CE-marked).
- STUDY DESIGN AND POPULATION
- This is an observational, cross-sectional, within-subject (split-mouth) study. Participants are patients in active clear aligner treatment who wear the two trimming-line designs, one per dental arch, prescribed as part of their orthodontic care. Each participant concurrently wears both designs and serves as their own control; the unit of comparison is the dental arch within the participant. Eligibility requires a minimum of four weeks of wear of the two designs. The planned enrollment is 70 participants.
- STUDY INSTRUMENT AND ADMINISTRATION
- The study instrument is a 20-item questionnaire developed for this study. The items address the functional and soft-tissue dimensions of aligner wear, including speech and phonation, mucosal and gingival sensation, retention and insertion, foreign-body sensation, and salivation and taste, corresponding to the oral surfaces in contact with the aligner margin. Each item is rated for frequency of occurrence during wear on a three-point ordinal scale (0 = none, 1 = occasional, 2 = frequent) and is answered separately for the maxillary and mandibular arch. The questionnaire is administered once, online, and is anonymous; no personal or identifying data are collected. Participants are aware that they are wearing two distinct trimming-line designs but are not informed which design corresponds to which arch, in order to limit response (expectation) bias.
- DESIGN ALLOCATION AND ANALYSIS
- The trimming-line design allocated to each arch varies among participants. Two identical questionnaire forms are employed: one is completed by participants in whom the maxillary arch carries the supragingival design (mandibular juxtagingival), and the other by participants with the reciprocal allocation. The form completed thereby encodes the arch-to-design correspondence without recourse to a participant identifier or any identifying data, preserving anonymity. Responses are classified by design accordingly, and supragingival and juxtagingival responses are compared within each participant. The primary analysis is an item-level comparison between designs using a paired non-parametric test (Wilcoxon signed-rank, two-sided, alpha = 0.05), supplemented by descriptive statistics (frequencies, means, standard deviations). A pre-specified secondary analysis compares the per-design total score (range 0 to 40), with assessment of internal consistency (Cronbach's alpha).
- RELATIONSHIP TO THE RESEARCH PROGRAM
- This study is the patient-experience component of a coordinated doctoral research program of four parallel split-mouth investigations of clear aligner trimming-line design (periodontal status, subgingival microbiota, optical stability, and patient-reported comfort); findings are interpreted alongside the companion studies at the group level.
Studietype
Observationeel
Inschrijving (Werkelijk)
70
Contacten en locaties
In dit gedeelte vindt u de contactgegevens van degenen die het onderzoek uitvoeren en informatie over waar dit onderzoek wordt uitgevoerd.
Studie Locaties
-
-
Sibiu County
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Sibiu, Sibiu County, Roemenië, 550027
- Aorys Clinic
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-
Deelname Criteria
Onderzoekers zoeken naar mensen die aan een bepaalde beschrijving voldoen, de zogenaamde geschiktheidscriteria. Enkele voorbeelden van deze criteria zijn iemands algemene gezondheidstoestand of eerdere behandelingen.
Geschiktheidscriteria
Leeftijden die in aanmerking komen voor studie
- Kind
- Volwassen
- Oudere volwassene
Accepteert gezonde vrijwilligers
Ja
Bemonsteringsmethode
Niet-waarschijnlijkheidssteekproef
Studie Bevolking
Adolescent and adult patients (aged 15 years or older) in active orthodontic treatment with clear aligners, including finishing (refinement) aligners, in whom a supragingival trimming-line design is worn on one dental arch and a juxtagingival design on the contralateral arch.
Eligible participants have worn the two designs for at least four weeks at the time the questionnaire is completed.
Recruitment is conducted at a single orthodontic practice.
Beschrijving
Inclusion Criteria:
- Adolescent or adult patient (aged 15 years or older)
- Active orthodontic treatment with clear aligners, including finishing (refinement) aligners
- Wearing two clear aligners with different trimming-line designs, one per dental arch: a supragingival design on one arch and a juxtagingival design on the contralateral arch
- At least 4 weeks of wear of the two designs at the time of questionnaire completion
- Good treatment compliance
- Willing and able to complete the online questionnaire and provide the required consent
Exclusion Criteria:
- Mixed orthodontic treatment (aligners combined with fixed appliances)
- Pre-existing neurological, cognitive, or speech disorders
- Systemic conditions affecting the oral cavity (e.g., xerostomia, mucosal disorders)
Studie plan
Dit gedeelte bevat details van het studieplan, inclusief hoe de studie is opgezet en wat de studie meet.
Hoe is de studie opgezet?
Ontwerpdetails
Cohorten en interventies
Groep / Cohort |
Interventie / Behandeling |
|---|---|
|
Group/Cohort (1): Split-mouth participants (both trimming-line designs)
Patients wearing the supragingival trimming-line design on one dental arch and the juxtagingival design on the contralateral arch, who completed the comfort questionnaire after at least four weeks of wear.
|
Clear aligner edge covering approximately 2 mm of marginal gingiva (straight cut), worn on one dental arch.
Clear aligner edge following the scalloped gingival contour, terminating at the free gingival margin without covering the gingiva, worn on the contralateral arch.
|
Wat meet het onderzoek?
Primaire uitkomstmaten
Uitkomstmaat |
Maatregel Beschrijving |
Tijdsspanne |
|---|---|---|
|
Per-item patient-reported frequency (0-2) for the supragingival versus juxtagingival design
Tijdsspanne: Day 28 (+/- 2 days) after the start of wear of the two designs
|
For each of the 20 questionnaire items (each rated 0 = no, 1 = occasionally, 2 = frequently, recorded separately for the two dental arches), the response associated with the supragingival design is compared with the response associated with the juxtagingival design within each participant, using a paired non-parametric test (Wilcoxon signed-rank, two-sided, alpha 0.05).
Responses are also summarized descriptively (frequencies, means, standard deviations).
|
Day 28 (+/- 2 days) after the start of wear of the two designs
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Secundaire uitkomstmaten
Uitkomstmaat |
Maatregel Beschrijving |
Tijdsspanne |
|---|---|---|
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Total patient-reported discomfort score per design (0-40)
Tijdsspanne: Day 28 (+/- 2 days) after the start of wear of the two designs
|
Pre-specified secondary analysis.
For each participant, the 20 item scores associated with each design are summed to a total from 0 (no reported discomfort) to 40 (maximum reported frequency across all items); the supragingival and juxtagingival totals are compared within participants (Wilcoxon signed-rank, two-sided, alpha 0.05).
Internal consistency of the total score is assessed (Cronbach's alpha).
|
Day 28 (+/- 2 days) after the start of wear of the two designs
|
Medewerkers en onderzoekers
Hier vindt u mensen en organisaties die betrokken zijn bij dit onderzoek.
Onderzoekers
- Hoofdonderzoeker: EMILIA (PRODEA) RUSU, George Emil Palade University of Medicine, Pharmacy, Sciences, and Technology of Targu Mures, 38 Gheorghe Marinescu Street, 540139 Targu Mures, Romania
- Studie stoel: LUMINITA LAZAR, DDS, PhD, George Emil Palade University of Medicine, Pharmacy, Sciences, and Technology of Targu Mures, 38 Gheorghe Marinescu Street, 540139 Targu Mures, Romania
Publicaties en nuttige links
De persoon die verantwoordelijk is voor het invoeren van informatie over het onderzoek stelt deze publicaties vrijwillig ter beschikking. Dit kan gaan over alles wat met het onderzoek te maken heeft.
Algemene publicaties
- Jaber ST, Hajeer MY, Burhan AS, Latifeh Y. The Effect of Treatment With Clear Aligners Versus Fixed Appliances on Oral Health-Related Quality of Life in Patients With Severe Crowding: A One-Year Follow-Up Randomized Controlled Clinical Trial. Cureus. 2022 May 30;14(5):e25472. doi: 10.7759/cureus.25472. eCollection 2022 May.
- Zhang B, Huang X, Huo S, Zhang C, Zhao S, Cen X, Zhao Z. Effect of clear aligners on oral health-related quality of life: A systematic review. Orthod Craniofac Res. 2020 Nov;23(4):363-370. doi: 10.1111/ocr.12382. Epub 2020 May 13.
- Rusu EP, Lazar AP, Erhan BL, Bud E, Pacurar M, Lazar L. Clear Aligner Therapy and Marginal Edge Design: Clinical and Laboratory Evidence on Periodontal and Biological Outcomes-A Scoping Review. Dent J (Basel). 2026 Feb 24;14(3):130. doi: 10.3390/dj14030130.
- Crego-Ruiz M, Jorba-Garcia A. Assessment of the periodontal health status and gingival recession during orthodontic treatment with clear aligners and fixed appliances: A systematic review and meta-analysis. Med Oral Patol Oral Cir Bucal. 2023 Jul 1;28(4):e330-e340. doi: 10.4317/medoral.25760.
- Tunca Y, Kaya Y, Tunca M, Keskin S. Comparison of anxiety, pain, and quality of life in individuals with mild or moderate malocclusion between conventional fixed orthodontic treatment versus Invisalign: a randomised clinical trial. BMC Oral Health. 2024 May 17;24(1):576. doi: 10.1186/s12903-024-04335-1.
- Alajmi S, Shaban A, Al-Azemi R. Comparison of Short-Term Oral Impacts Experienced by Patients Treated with Invisalign or Conventional Fixed Orthodontic Appliances. Med Princ Pract. 2020;29(4):382-388. doi: 10.1159/000505459. Epub 2019 Dec 17.
- Di Spirito F, D'Ambrosio F, Cannata D, D'Anto V, Giordano F, Martina S. Impact of Clear Aligners versus Fixed Appliances on Periodontal Status of Patients Undergoing Orthodontic Treatment: A Systematic Review of Systematic Reviews. Healthcare (Basel). 2023 May 6;11(9):1340. doi: 10.3390/healthcare11091340.
- Nakornnoi T, Srirodjanakul W, Chintavalakorn R, Santiwong P, Sipiyaruk K. The biomechanical effects of clear aligner trimline designs and extensions on orthodontic tooth movement: a systematic review. BMC Oral Health. 2024 Dec 20;24(1):1523. doi: 10.1186/s12903-024-05274-7.
Studie record data
Deze datums volgen de voortgang van het onderzoeksdossier en de samenvatting van de ingediende resultaten bij ClinicalTrials.gov. Studieverslagen en gerapporteerde resultaten worden beoordeeld door de National Library of Medicine (NLM) om er zeker van te zijn dat ze voldoen aan specifieke kwaliteitscontrolenormen voordat ze op de openbare website worden geplaatst.
Bestudeer belangrijke data
Studie start (Werkelijk)
1 juli 2026
Primaire voltooiing (Werkelijk)
7 augustus 2026
Studie voltooiing (Werkelijk)
7 augustus 2026
Studieregistratiedata
Eerst ingediend
16 juni 2026
Eerst ingediend dat voldeed aan de QC-criteria
16 juni 2026
Eerst geplaatst (Werkelijk)
22 juni 2026
Updates van studierecords
Laatste update geplaatst (Werkelijk)
21 augustus 2026
Laatste update ingediend die voldeed aan QC-criteria
20 augustus 2026
Laatst geverifieerd
1 augustus 2026
Meer informatie
Termen gerelateerd aan deze studie
Trefwoorden
Aanvullende relevante MeSH-voorwaarden
Andere studie-ID-nummers
- COMFORT-ALIGN-ORTHO
- 3885/2025 (Andere identificatie: Ethics Committee for Scientific Research, UMFST Targu Mures)
Plan Individuele Deelnemersgegevens (IPD)
Bent u van plan om gegevens van individuele deelnemers (IPD) te delen?
JA
Beschrijving IPD-plan
The study collects anonymous questionnaire responses, with no participant code or identifying data; the trimming-line design per arch is derived from which of two identical forms a participant completed.
A minimal de-identified dataset (per-design total discomfort scores) will be made available upon reasonable request to the corresponding author following publication.
Companion-study data are not linked.
IPD-tijdsbestek voor delen
Beginning 6 months after publication of primary study results.
IPD-toegangscriteria voor delen
Upon reasonable request to the corresponding author (PI); requests reviewed within 30 days.
IPD delen Ondersteunend informatietype
- LEERPROTOCOOL
- SAP
Informatie over medicijnen en apparaten, studiedocumenten
Bestudeert een door de Amerikaanse FDA gereguleerd geneesmiddel
Nee
Bestudeert een door de Amerikaanse FDA gereguleerd apparaatproduct
Nee
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