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Marginal Biofilm Distribution and Periodontal Response to Supragingival and Juxtagingival Aligner Designs (BIOFILM-ALIGN)

15 juli 2026 bijgewerkt door: Emilia Rusu, George Emil Palade University of Medicine, Pharmacy, Sciences and Technology of Targu Mures

Marginal Biofilm Distribution and Periodontal Response to Supragingival and Juxtagingival Aligner Designs: A Prospective Split-Mouth Clinical Study

  • 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.

Studie Overzicht

Toestand

Voltooid

Conditie

Interventie / Behandeling

Gedetailleerde beschrijving

  • BACKGROUND AND RATIONALE
  • Clear aligner therapy is widely used in contemporary orthodontics. The geometry of the aligner trimming line at the gingival margin differs between two commonly used designs: a supragingival design that covers a band of marginal gingiva, and a juxtagingival design that follows the gingival contour. Biomechanical investigations have characterized how trimming-line geometry affects force transmission and retention, and a limited number of clinical reports have examined its periodontal effects. However, direct clinical comparisons of trimming-line geometry on periodontal outcomes remain scarce and have been limited largely to adolescent populations and to conventional periodontal indices; within-person comparisons in adults, and the distribution of biofilm on the marginal soft tissues, remain insufficiently characterized. This study addresses that gap.
  • THE TWO TRIMMING-LINE DESIGNS 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. Both designs are produced from the same CE-marked tri-layer clear aligner material (CA Pro, SCHEU-DENTAL GmbH, Iserlohn, Germany) and are standard variations used in routine orthodontic practice. The intervention under study is the trimming-line design, a manufacturing parameter, not the aligner material or device itself.
  • STUDY DESIGN This is a prospective, longitudinal, within-person (split-mouth) interventional study. Each participant receives both trimming-line designs simultaneously, one on the maxillary arch and one on the mandibular arch, and therefore serves as their own control. The unit of comparison is the dental arch within the participant. The split-mouth design controls for inter-individual variation in systemic health, oral hygiene, salivary characteristics, and baseline periodontal status. The within-person (split-mouth) design was chosen to maximize statistical efficiency in an exploratory clinical evaluation, with each participant serving as their own control.
  • ALLOCATION RULE (NON-RANDOMIZED) Allocation of each design to an arch is not randomized. It follows a pre-specified rule based on the orthodontic treatment plan. The primary criterion is the magnitude of planned dental intrusion per arch, derived from the digital treatment setup prepared before aligner fabrication: the arch with the greater planned intrusion receives the supragingival design. When planned intrusion is equal on both arches or absent, a pre-specified alternating sequence in enrollment order is applied as a tiebreaker, with the first such participant receiving the supragingival design on the maxillary arch, the next on the mandibular arch, and so on. This produces an approximately balanced arch-level distribution. Planned intrusion magnitude is used only as the basis for this allocation rule; it is not entered as a covariate in the analysis, and the study does not analyze the relationship between intrusion magnitude and hard-tissue outcomes (root or alveolar bone).
  • CLINICAL AND PHOTOGRAPHIC ASSESSMENTS Assessments are performed at baseline before aligner delivery (T0), at three months (T1, plus or minus 7 days), and at six months (T2, plus or minus 7 days). At each visit, full-mouth periodontal charting (probing depth and bleeding on probing) is performed first, on undisclosed tissue, by a calibrated examiner who is blinded to the trimming-line allocation; conventional plaque assessment is then performed using a two-tone disclosing agent and the Turesky-Quigley-Hein plaque index; and standardized intraoral photographs are obtained afterwards.
  • EXPLORATORY PHOTOGRAPHIC VARIABLES Three photographic soft-tissue variables, namely marginal gingival plaque presence, vestibular interdental papilla plaque presence, and the marginal demarcation pattern, were developed for this study to describe the distribution of biofilm on the marginal gingival soft tissues, a dimension not captured by conventional hard-surface plaque indices. These variables are designated as exploratory. The photographs are de-identified, coded, and presented in randomized order to two independent blinded examiners, and inter-examiner agreement is assessed using the Cohen kappa coefficient.
  • ANALYSIS The primary comparison is the within-person, between-arch difference in the percentage of sites with bleeding on probing at six months (T2), with baseline (T0) as the reference and each participant serving as their own control. The three-month (T1) assessment is analyzed as a secondary, intermediate time point describing the trajectory of periodontal response. The secondary validated outcomes, probing depth and the plaque index, are analyzed within the same within-person framework across all time points. The exploratory photographic variables are summarized descriptively, and their effect estimates are reported to inform the design of future confirmatory studies. All tests are two-sided, with the significance level set at 0.05.
  • SAFETY Both trimming-line designs are standard variations used in routine clinical orthodontic practice with a CE-marked aligner material, and neither constitutes a novel or experimental device. Untoward periodontal or soft-tissue events occurring during the study are recorded at each scheduled visit and may be reported by participants between visits. Predefined clinical criteria are applied for the withdrawal of a participant when continued participation would no longer be in the participant's clinical interest.
  • LIMITATIONS Allocation is not randomized and is tied to the planned intrusion per arch. Because intrusion magnitude is not adjusted for in the analysis, between-arch differences may partly reflect the clinically driven allocation rather than the trimming-line design alone; this is acknowledged in the interpretation of the results. The split-mouth design reduces inter-individual variation but cannot exclude arch-level biomechanical differences other than the trimming-line design.

Studietype

Ingrijpend

Inschrijving (Werkelijk)

20

Fase

  • Niet toepasbaar

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

  • Roemenië
    • Sibiu County
      • Sibiu, Sibiu County, Roemenië, 550027
        • Aorys Clinic

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

  • Volwassen
  • Oudere volwassene

Accepteert gezonde vrijwilligers

Ja

Beschrijving

Inclusion Criteria:

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

Exclusion Criteria:

  • 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

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

  • Primair doel: Fundamentele wetenschap
  • Toewijzing: Niet-gerandomiseerd
  • Interventioneel model: Crossover-opdracht
  • Masker: Enkel

Wapens en interventies

Deelnemersgroep / Arm
Interventie / Behandeling
Experimenteel: Supragingival Trimming-Line Design
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.
Apparaat: Supragingival aligner trimming-line
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.
Actieve vergelijker: Juxtagingival Festooned Trimming-Line Design
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.
Apparaat: Juxtagingival festooned aligner trimming-line
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.

Wat meet het onderzoek?

Primaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Bleeding on probing at 6 months (percentage of sites per arch)
Tijdsspanne: Baseline (T0, before aligner delivery) and 6 months (T2)
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)

Secundaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Bleeding on probing at 3 months (intermediate, percentage of sites per arch)
Tijdsspanne: 3 months (T1)
Percentage of sites with bleeding on probing within each dental arch at the 3-month assessment, recorded and computed identically to the primary outcome (six sites per tooth, present or absent within approximately 10 to 15 seconds of gentle probing), compared between arches by trimming-line design. This intermediate time point describes the trajectory of periodontal response and is not the primary comparison.
3 months (T1)
Mean probing depth (per arch)
Tijdsspanne: Baseline (T0), 3 months (T1), and 6 months (T2)
Arithmetic mean of probing depth values (mm) within each dental arch, measured at six sites per tooth using a calibrated periodontal probe, calculated separately for each arch and compared by trimming-line design.
Baseline (T0), 3 months (T1), and 6 months (T2)
Maximum probing depth (per arch)
Tijdsspanne: Baseline (T0), 3 months (T1), and 6 months (T2)
The greatest single probing depth value (mm) recorded within each dental arch, calculated separately for each arch and compared by trimming-line design.
Baseline (T0), 3 months (T1), and 6 months (T2)
Turesky-Quigley-Hein plaque index (per arch)
Tijdsspanne: Baseline (T0), 3 months (T1), and 6 months (T2)
Mean plaque score on the Turesky-Quigley-Hein ordinal scale (0 to 5), recorded on the vestibular surfaces of teeth after application of a two-tone plaque-disclosing agent (Rondell, Directa AB, Sweden), calculated separately for each dental arch and compared by trimming-line design.
Baseline (T0), 3 months (T1), and 6 months (T2)

Andere uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Marginal Gingival Plaque Presence (MGPP%)
Tijdsspanne: Baseline (T0), 3 months (T1), and 6 months (T2)
Percentage of tooth-associated gingival units showing disclosed plaque on the vestibular aspect of the free gingival margin (within 0 to 2 mm of the gingival crest), scored as present or absent per unit from standardized intraoral photographs by two independent blinded examiners, calculated per arch.
Baseline (T0), 3 months (T1), and 6 months (T2)
Vestibular Interdental Papilla Plaque Presence (VIPPP%)
Tijdsspanne: Baseline (T0), 3 months (T1), and 6 months (T2)
Percentage of interdental papillary units showing disclosed plaque on the visible vestibular aspect of the interdental papilla, scored as present or absent per unit from standardized intraoral photographs by two independent blinded examiners, calculated per arch.
Baseline (T0), 3 months (T1), and 6 months (T2)
Marginal Demarcation Pattern (MDP)
Tijdsspanne: Baseline (T0), 3 months (T1), and 6 months (T2)
Categorical classification of the predominant pattern of disclosed marginal plaque distribution on the buccal gingiva, scored per arch from standardized intraoral photographs by two independent examiners blinded to allocation. The categories are morphological, not ordinal severity levels: 0 = absent (no disclosed plaque pattern on the marginal gingiva); 1 = diffuse (disclosed plaque scattered over the gingiva without a defined coronal outline); 2 = papillary (disclosed plaque confined to the interdental papillae); 3 = linear/band (a continuous, clearly demarcated horizontal band of disclosed plaque spanning the buccal aspect of two or more adjacent teeth, including the papilla between them). The numeric codes denote distinct categories and not increasing severity; the predominant pattern is recorded for each arch. Inter-examiner agreement is assessed using the Cohen kappa coefficient for nominal categories.
Baseline (T0), 3 months (T1), and 6 months (T2)

Medewerkers en onderzoekers

Hier vindt u mensen en organisaties die betrokken zijn bij dit onderzoek.

Sponsor

George Emil Palade University of Medicine, Pharmacy, Sciences and Technology of Targu Mures

Medewerkers

Orto Performance Orthodontic Laboratory, Cluj-Napoca, Romania (aligner fabrication)

Onderzoekers

  • Studie stoel: 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

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

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 maart 2025

Primaire voltooiing (Werkelijk)

15 juli 2026

Studie voltooiing (Werkelijk)

15 juli 2026

Studieregistratiedata

Eerst ingediend

6 juni 2026

Eerst ingediend dat voldeed aan de QC-criteria

6 juni 2026

Eerst geplaatst (Werkelijk)

11 juni 2026

Updates van studierecords

Laatste update geplaatst (Werkelijk)

16 juli 2026

Laatste update ingediend die voldeed aan QC-criteria

15 juli 2026

Laatst geverifieerd

1 juli 2026

Meer informatie

Termen gerelateerd aan deze studie

Trefwoorden

Aanvullende relevante MeSH-voorwaarden

Andere studie-ID-nummers

  • BIOFILM ALIGN-ORTHO

Plan Individuele Deelnemersgegevens (IPD)

Bent u van plan om gegevens van individuele deelnemers (IPD) te delen?

NEE

Beschrijving IPD-plan

Individual participant data will not be made publicly available, as the small single-site cohort (20 participants) cannot be fully de-identified without risk to participant confidentiality. De-identified data may be made available from the principal investigator on reasonable academic request, subject to an appropriate data-sharing agreement and ethics approval. Aggregate results will be reported in the doctoral thesis and in peer-reviewed publication.

Informatie over medicijnen en apparaten, studiedocumenten

Bestudeert een door de Amerikaanse FDA gereguleerd geneesmiddel

Nee

Bestudeert een door de Amerikaanse FDA gereguleerd apparaatproduct

Nee

Deze informatie is zonder wijzigingen rechtstreeks van de website clinicaltrials.gov gehaald. Als u verzoeken heeft om uw onderzoeksgegevens te wijzigen, te verwijderen of bij te werken, neem dan contact op met register@clinicaltrials.gov. Zodra er een wijziging wordt doorgevoerd op clinicaltrials.gov, wordt deze ook automatisch bijgewerkt op onze website .

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