Marginal Biofilm Distribution and Periodontal Response to Supragingival and Juxtagingival Aligner Designs

NCT07642037 | Active Not Recruiting

• 1 other identifier: BIOFILM ALIGN-ORTHO
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

• This prospective, longitudinal, within-person (split-mouth) clinical study evaluates the influence of two clear aligner trimming-line designs on marginal soft-tissue biofilm distribution and periodontal tissue response over a six-month period.
• Two trimming-line designs are compared. The supragingival design has a straight, horizontal edge that extends approximately 2 mm onto the marginal gingiva, resting in direct contact with the gingival surface but not entering the gingival sulcus. The juxtagingival design follows the scalloped contour of the gingival margin and terminates at the free gingival margin, without covering the gingiva and without entering the sulcus.
• Each participant receives both designs simultaneously, one per dental arch, and therefore serves as their own control. The assignment of each design to an arch is determined by the treating clinician according to the orthodontic treatment indications and is not randomized.
• The primary outcome is the percentage of sites with bleeding on probing per arch at six months. Secondary outcomes are bleeding on probing at three months, mean probing depth, maximum probing depth, and the Turesky-Quigley-Hein plaque index, with three exploratory photographic soft-tissue variables describing marginal gingival plaque presence, vestibular interdental papilla plaque presence, and the marginal demarcation pattern. Clinical and photographic assessments are performed at baseline (before aligner delivery), at three months, and at six months.
• All aligners are fabricated from a tri-layer clear aligner material (CA Pro, SCHEU-DENTAL GmbH, Iserlohn, Germany) by a single orthodontic laboratory.

Conditions

Periodontal Diseases; Dental Plaque; Gingivitis

Keywords

clear aligner; trimming line; aligner trimming-line design; gingival margin; supragingival; juxtagingival; festooned margin; bleeding on probing; dental plaque; biofilm distribution; soft-tissue plaque; marginal gingiva; split-mouth; periodontal response; Turesky-Quigley-Hein plaque index; photographic assessment; marginal demarcation pattern

Outcome Measures

Primary Outcomes (1)

• Bleeding on probing at 6 months (percentage of sites per arch)

  Percentage of sites with bleeding on probing within each dental arch. Bleeding on probing is recorded as present or absent within approximately 10 to 15 seconds after gentle probing at six sites per tooth (mesiobuccal, mid-buccal, distobuccal, mesiolingual, mid-lingual, distolingual) using a calibrated periodontal probe. The percentage is calculated as the number of bleeding sites divided by the total number of scorable sites in the arch, multiplied by 100. The two arches within each participant are compared by trimming-line design. The primary endpoint is the within-person, between-arch difference at 6 months (T2), with baseline (T0) as the reference. The 3-month (T1) assessment is analyzed as a secondary, intermediate time point and does not contribute to the primary comparison.

  Baseline (T0, before aligner delivery) and 6 months (T2)

Secondary Outcomes (4)

• Bleeding on probing at 3 months (intermediate, percentage of sites per arch)

  3 months (T1)

• Mean probing depth (per arch)

  Baseline (T0), 3 months (T1), and 6 months (T2)

• Maximum probing depth (per arch)

  Baseline (T0), 3 months (T1), and 6 months (T2)

• Turesky-Quigley-Hein plaque index (per arch)

  Baseline (T0), 3 months (T1), and 6 months (T2)

Other Outcomes (3)

• Marginal Gingival Plaque Presence (MGPP%)

  Baseline (T0), 3 months (T1), and 6 months (T2)

• Vestibular Interdental Papilla Plaque Presence (VIPPP%)

  Baseline (T0), 3 months (T1), and 6 months (T2)

• Marginal Demarcation Pattern (MDP)

  Baseline (T0), 3 months (T1), and 6 months (T2)

Study Arms (2)

Supragingival Trimming-Line Design

EXPERIMENTAL

Dental arch fitted with a clear aligner trimmed with a supragingival straight-cut margin. The aligner edge extends approximately 2 mm onto the marginal gingiva, in direct contact with the gingival surface but without entering the gingival sulcus. Assigned to the arch with the greater planned intrusion; when planned intrusion is equal or absent on both arches, assignment follows a pre-specified alternating sequence in enrollment order.

Device: Supragingival aligner trimming-line

Juxtagingival Festooned Trimming-Line Design

ACTIVE COMPARATOR

Contralateral dental arch, within the same participant, fitted with a clear aligner trimmed with a juxtagingival festooned margin that follows the scalloped contour of the gingival margin and terminates at the free gingival margin, without covering the gingiva and without entering the sulcus. Assigned to the arch with the lesser or no planned intrusion.

Device: Juxtagingival festooned aligner trimming-line

Interventions

Juxtagingival festooned aligner trimming-line DEVICE

Clear aligner trimmed with a juxtagingival festooned margin following the scalloped gingival contour, terminating at the free gingival margin without covering the gingiva or entering the sulcus. Fabricated from CA Pro tri-layer thermoplastic material (SCHEU-DENTAL GmbH, Iserlohn, Germany; CE-marked) by Orto Performance Orthodontic Laboratory, Cluj-Napoca, Romania. The intervention under study is the trimming-line design, not the aligner material; material and thickness are identical to the comparator.

Juxtagingival Festooned Trimming-Line Design

Supragingival aligner trimming-line DEVICE

Clear aligner trimmed with a supragingival straight-cut margin extending approximately 2 mm onto the marginal gingiva, in direct contact with the gingiva but not entering the sulcus. Fabricated from CA Pro tri-layer thermoplastic material (SCHEU-DENTAL GmbH, Iserlohn, Germany; CE-marked) by Orto Performance Orthodontic Laboratory, Cluj-Napoca, Romania. The intervention under study is the trimming-line design, not the aligner material; material and thickness are identical to the comparator.

Supragingival Trimming-Line Design

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Permanent dentition
• Adult patients
• Mild to moderate crowding not requiring extractions for orthodontic purposes

You may not qualify if:

• Mouth breathing (may influence the status of the marginal periodontium)
• Periodontal involvement (gingivitis or periodontitis)
• Presence of fixed prosthetic restorations with incorrect marginal adaptation
• Deficient oral hygiene

Sponsors & Collaborators

• George Emil Palade University of Medicine, Pharmacy, Sciences and Technology of Targu Mures: lead
• Orto Performance Orthodontic Laboratory, Cluj-Napoca, Romania (aligner fabrication): collaborator

Study Sites (1)

Aorys Clinic

Sibiu, Sibiu County, 550027, Romania

Location

Related Publications (8)

• 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.

  PMID: 36641738 BACKGROUND

• 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.

  PMID: 41892738 BACKGROUND

• Favero R, Libralato L, Balestro F, Volpato A, Favero L. Edge level of aligners and periodontal health: a clinical perspective study in young patients. Dental Press J Orthod. 2023 Apr 14;28(1):e2321124. doi: 10.1590/2177-6709.28.1.e2321124.oar. eCollection 2023.

  PMID: 37075415 BACKGROUND

• Espana-Pamplona P, Bernes-Martinez L, Andres-Castello C, Bolas-Colvee B, Adobes-Martin M, Garcovich D. Changes in the Oral Microbiota with the Use of Aligners vs. Braces: A Systematic Review. J Clin Med. 2024 Dec 6;13(23):7435. doi: 10.3390/jcm13237435.

  PMID: 39685893 BACKGROUND

• Elshazly TM, Keilig L, Salvatori D, Chavanne P, Aldesoki M, Bourauel C. Effect of trimming line design and edge extension of orthodontic aligners on force transmission: An in vitro study. J Dent. 2022 Oct;125:104276. doi: 10.1016/j.jdent.2022.104276. Epub 2022 Aug 30.

  PMID: 36055460 BACKGROUND

• Lyu X, Cao X, Yan J, Zeng R, Tan J. Biomechanical effects of clear aligners with different thicknesses and gingival-margin morphology for appliance design optimization. Am J Orthod Dentofacial Orthop. 2023 Aug;164(2):239-252. doi: 10.1016/j.ajodo.2022.12.014. Epub 2023 Mar 21.

  PMID: 36935221 BACKGROUND

• Elshazly TM, Bourauel C, Chavanne P, Elattar H, Keilig L. Numerical biomechanical finite element analysis of different trimming line designs of orthodontic aligners: An in silico study. J World Fed Orthod. 2024 Apr;13(2):65-71. doi: 10.1016/j.ejwf.2024.01.001. Epub 2024 Feb 23.

  PMID: 38395726 BACKGROUND

• Rouzi M, Zhang X, Jiang Q, Long H, Lai W, Li X. Impact of Clear Aligners on Oral Health and Oral Microbiome During Orthodontic Treatment. Int Dent J. 2023 Oct;73(5):603-611. doi: 10.1016/j.identj.2023.03.012. Epub 2023 Apr 25.

  PMID: 37105789 BACKGROUND

MeSH Terms

Conditions

Periodontal Diseases; Dental Plaque; Gingivitis

Condition Hierarchy (Ancestors)

Mouth Diseases; Stomatognathic Diseases; Dental Deposits; Tooth Diseases; Infections; Gingival Diseases

Study Officials

• LUMINITA LAZAR, PhD, Professor

  George Emil Palade University of Medicine, Pharmacy, Sciences, and Technology of Targu Mures, 38 Gheorghe Marinescu Street, 540139 Targu Mures, Romania

  STUDY CHAIR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: Outcome assessor masking. Clinical periodontal assessments (probing depth and bleeding on probing) are performed by a calibrated examiner blinded to the trimming-line allocation; at each visit the participant removes both aligners before the examiner enters, and the examiner has no access to treatment plans or allocation records. Periodontal charting is performed on undisclosed tissue, before the disclosing agent and photography; the plaque-based marginal demarcation has no clinically visible tissue component and is therefore not perceptible at the time of clinical assessment. Photographic outcomes are scored independently by two examiners blinded to allocation, from de-identified images coded with random identifiers and presented in randomized order; inter-examiner agreement is assessed using the Cohen kappa coefficient. The treating clinician, who assigns the designs, is not an outcome assessor.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: This is a within-person split-mouth design in which each participant receives both trimming-line interventions simultaneously: the supragingival design on one dental arch and the juxtagingival festooned design on the contralateral arch. Allocation is non-randomized and clinician-determined, following a pre-specified rule based on the planned intrusion magnitude per arch (see Detailed Description).

Study Record Dates

• First Submitted: June 6, 2026
• First Posted: June 11, 2026
• Study Start: March 1, 2025
• Primary Completion (Estimated): July 1, 2026
• Study Completion (Estimated): July 1, 2026
• Last Updated: June 12, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

RO (1)