Comparison of Patient-Reported Comfort Between Two Clear Aligner Trimming-Line Designs: A Split-Mouth Study (COMFORT-ALIGN)
20 août 2026 mis à jour par: 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.
Aperçu de l'étude
Statut
Complété
Les conditions
Intervention / Traitement
Description détaillée
- 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.
Type d'étude
Observationnel
Inscription (Réel)
70
Contacts et emplacements
Cette section fournit les coordonnées de ceux qui mènent l'étude et des informations sur le lieu où cette étude est menée.
Lieux d'étude
-
-
Sibiu County
-
Sibiu, Sibiu County, Roumanie, 550027
- Aorys Clinic
-
-
Critères de participation
Les chercheurs recherchent des personnes qui correspondent à une certaine description, appelée critères d'éligibilité. Certains exemples de ces critères sont l'état de santé général d'une personne ou des traitements antérieurs.
Critère d'éligibilité
Âges éligibles pour étudier
- Enfant
- Adulte
- Adulte plus âgé
Accepte les volontaires sains
Oui
Méthode d'échantillonnage
Échantillon non probabiliste
Population étudiée
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.
La description
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)
Plan d'étude
Cette section fournit des détails sur le plan d'étude, y compris la façon dont l'étude est conçue et ce que l'étude mesure.
Comment l'étude est-elle conçue ?
Détails de conception
Cohortes et interventions
Groupe / Cohorte |
Intervention / Traitement |
|---|---|
|
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.
|
Que mesure l'étude ?
Principaux critères de jugement
Mesure des résultats |
Description de la mesure |
Délai |
|---|---|---|
|
Per-item patient-reported frequency (0-2) for the supragingival versus juxtagingival design
Délai: 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
|
Mesures de résultats secondaires
Mesure des résultats |
Description de la mesure |
Délai |
|---|---|---|
|
Total patient-reported discomfort score per design (0-40)
Délai: 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
|
Collaborateurs et enquêteurs
C'est ici que vous trouverez les personnes et les organisations impliquées dans cette étude.
Parrainer
Les enquêteurs
- Chercheur principal: EMILIA (PRODEA) RUSU, George Emil Palade University of Medicine, Pharmacy, Sciences, and Technology of Targu Mures, 38 Gheorghe Marinescu Street, 540139 Targu Mures, Romania
- Chaise d'étude: 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
Publications et liens utiles
La personne responsable de la saisie des informations sur l'étude fournit volontairement ces publications. Il peut s'agir de tout ce qui concerne l'étude.
Publications générales
- 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.
Dates d'enregistrement des études
Ces dates suivent la progression des dossiers d'étude et des soumissions de résultats sommaires à ClinicalTrials.gov. Les dossiers d'étude et les résultats rapportés sont examinés par la Bibliothèque nationale de médecine (NLM) pour s'assurer qu'ils répondent à des normes de contrôle de qualité spécifiques avant d'être publiés sur le site Web public.
Dates principales de l'étude
Début de l'étude (Réel)
1 juillet 2026
Achèvement primaire (Réel)
7 août 2026
Achèvement de l'étude (Réel)
7 août 2026
Dates d'inscription aux études
Première soumission
16 juin 2026
Première soumission répondant aux critères de contrôle qualité
16 juin 2026
Première publication (Réel)
22 juin 2026
Mises à jour des dossiers d'étude
Dernière mise à jour publiée (Réel)
21 août 2026
Dernière mise à jour soumise répondant aux critères de contrôle qualité
20 août 2026
Dernière vérification
1 août 2026
Plus d'information
Termes liés à cette étude
Mots clés
Termes MeSH pertinents supplémentaires
Autres numéros d'identification d'étude
- COMFORT-ALIGN-ORTHO
- 3885/2025 (Autre identifiant: Ethics Committee for Scientific Research, UMFST Targu Mures)
Plan pour les données individuelles des participants (IPD)
Prévoyez-vous de partager les données individuelles des participants (DPI) ?
OUI
Description du régime IPD
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.
Délai de partage IPD
Beginning 6 months after publication of primary study results.
Critères d'accès au partage IPD
Upon reasonable request to the corresponding author (PI); requests reviewed within 30 days.
Type d'informations de prise en charge du partage d'IPD
- PROTOCOLE D'ÉTUDE
- SÈVE
Informations sur les médicaments et les dispositifs, documents d'étude
Étudie un produit pharmaceutique réglementé par la FDA américaine
Non
Étudie un produit d'appareil réglementé par la FDA américaine
Non
Ces informations ont été extraites directement du site Web clinicaltrials.gov sans aucune modification. Si vous avez des demandes de modification, de suppression ou de mise à jour des détails de votre étude, veuillez contacter register@clinicaltrials.gov. Dès qu'un changement est mis en œuvre sur clinicaltrials.gov, il sera également mis à jour automatiquement sur notre site Web .