Periodontal DiseasesBIOFILM-ALIGNNCT07642037
Marginal Biofilm Distribution and Periodontal Response to Supragingival and Juxtagingival Aligner Designs
A study testing Supragingival aligner trimming-line and Juxtagingival festooned aligner trimming-line in people with Periodontal Diseases and Dental Plaque, run by George Emil Palade University of Medicine, Pharmacy, Sciences and Technology of Targu Mures at 1 site in Romania.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Periodontal Diseases, Dental Plaque, Gingivitis
- What is being tested?
- Supragingival aligner trimming-line and Juxtagingival festooned aligner trimming-line
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteRomania
- Study dates
- 1 Mar 2025to 15 Jul 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Permanent dentition
- Adult patients
- Mild to moderate crowding not requiring extractions for orthodontic purposes
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
About this study
Official title: 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.
Read the detailed description
- 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.
- Conditions
- Periodontal Diseases, Dental Plaque, Gingivitis
- Being tested
- Supragingival aligner trimming-line, Juxtagingival festooned aligner trimming-line
- 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
- Medical subject headings
- Periodontal Diseases, Dental Plaque, Gingivitis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Supragingival aligner trimming-lineDevice
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.
Juxtagingival festooned aligner trimming-lineDevice
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.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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. Receives: Device: Juxtagingival festooned aligner trimming-line |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: Baseline (T0, before aligner delivery) and 6 months (T2)
Secondary outcomes (4)
Bleeding on probing at 3 months (intermediate, percentage of sites per arch)
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.
Measured: 3 months (T1)
Mean probing depth (per arch)
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.
Measured: Baseline (T0), 3 months (T1), and 6 months (T2)
Maximum probing depth (per arch)
The greatest single probing depth value (mm) recorded within each dental arch, calculated separately for each arch and compared by trimming-line design.
Measured: Baseline (T0), 3 months (T1), and 6 months (T2)
Turesky-Quigley-Hein plaque index (per arch)
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.
Measured: Baseline (T0), 3 months (T1), and 6 months (T2)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Jun 2026
- Study start1 Mar 2025
- Primary completion15 Jul 2026
- Study completion15 Jul 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (8)Papers the sponsor has linked to this study.
- Other trials for Periodontal DiseasesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Model description
- 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).
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- George Emil Palade University of Medicine, Pharmacy, Sciences and Technology of Targu Mures
- Sponsor type
- University, hospital or other
- Collaborators
- Orto Performance Orthodontic Laboratory, Cluj-Napoca, Romania (aligner fabrication)
- Responsible party
- Principal investigator, Emilia Rusu, George Emil Palade University of Medicine, Pharmacy, Sciences and Technology of Targu Mures
- Investigators
- LUMINITA LAZAR, PhD, Professor, Study chair, George Emil Palade University of Medicine, Pharmacy, Sciences, and Technology of Targu Mures, 38 Gheorghe Marinescu Street, 540139 Targu Mures, Romania
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07642037
- Sponsor's protocol ID
- BIOFILM ALIGN-ORTHO
- Acronym
- BIOFILM-ALIGN
- Status last verified
- Jul 2026
- First submitted
- 6 Jun 2026
- Last updated
- 16 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: 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.
Publications
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.
PubMed 36641738Rusu 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.
PubMed 41892738Favero 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.
PubMed 37075415Espana-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.
PubMed 39685893Elshazly 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.
PubMed 36055460Lyu 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.
PubMed 36935221Elshazly 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.
PubMed 38395726Rouzi 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.
PubMed 37105789
Study at a glance
From the registry record, last updated by the sponsor on 16 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Marginal Biofilm Distribution and Periodontal Response to Supragingival and Juxtagingival Aligner Designs: A Prospective Split-Mouth Clinical Study
- ClinicalTrials.gov ID
- NCT07642037
- Acronym / sponsor ID
- BIOFILM-ALIGN / BIOFILM ALIGN-ORTHO
- Conditions
- Periodontal Diseases, Dental Plaque, Gingivitis
- Keywords
- clear aligner, trimming line, aligner trimming-line design, gingival margin, supragingival, juxtagingival, festooned margin, bleeding on probing
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- George Emil Palade University of Medicine, Pharmacy, Sciences and Technology of Targu MuresUniversity, hospital or other
- Collaborators
- Orto Performance Orthodontic Laboratory, Cluj-Napoca, Romania (aligner fabrication)
- Study start
- 1 Mar 2025 (actual)
- Primary completion
- 15 Jul 2026 (actual)
- Study completion
- 15 Jul 2026 (actual)
- First posted
- 11 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
- 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.
Detailed description
- 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.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
- Model description
- 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).
| Arm | Type | Receives |
|---|---|---|
| Supragingival Trimming-Line Design | Experimental | Device: Supragingival aligner trimming-lineDental 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. |
| Juxtagingival Festooned Trimming-Line Design | Active comparator | Device: Juxtagingival festooned aligner trimming-lineContralateral 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. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Permanent dentition
- Adult patients
- Mild to moderate crowding not requiring extractions for orthodontic purposes
Key exclusion criteria (4 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Supragingival aligner trimming-lineClear 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. | Device | Supragingival Trimming-Line Design |
| Juxtagingival festooned aligner trimming-lineClear 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. | Device | Juxtagingival Festooned Trimming-Line Design |
Primary outcome
Bleeding on probing at 6 months (percentage of sites per arch)
Time frame: 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.
4 secondary outcomes
Bleeding on probing at 3 months (intermediate, percentage of sites per arch)
Time frame: 3 months (T1)
Mean probing depth (per arch)
Time frame: Baseline (T0), 3 months (T1), and 6 months (T2)
Maximum probing depth (per arch)
Time frame: Baseline (T0), 3 months (T1), and 6 months (T2)
Turesky-Quigley-Hein plaque index (per arch)
Time frame: Baseline (T0), 3 months (T1), and 6 months (T2)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 Jul 2026.
- Background: PubMed 36641738Crego-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.
- Background: PubMed 41892738Rusu 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.
- Background: PubMed 37075415Favero 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.
- Background: PubMed 39685893Espana-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.
- Background: PubMed 36055460Elshazly 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.
- Background: PubMed 36935221Lyu 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.
- Background: PubMed 38395726Elshazly 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.
- Background: PubMed 37105789Rouzi 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.
- Individual participant dataSharing planned: No. 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.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
LUMINITA LAZAR, PhD, Professor study chair
George Emil Palade University of Medicine, Pharmacy, Sciences, and Technology of Targu Mures, 38 Gheorghe Marinescu Street, 540139 Targu Mures, Romania
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Supragingival aligner trimming-line and Juxtagingival festooned aligner trimming-line in people with Periodontal Diseases and Dental Plaque, run by George Emil Palade University of Medicine, Pharmacy, Sciences and Technology of Targu Mures at 1 site in Romania.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 16 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Romania. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Bleeding on probing at 6 months (percentage of sites per arch) (time frame: Baseline (T0, before aligner delivery) and 6 months (T2)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07642037, which also lists 8 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Jul 2026.