Surface Roughness and Thickness Clear Aligner SheatNCT07449598
Evaluation of Physical Changes in Single-Layer and Multi-Layer Clear Aligners
A study testing clear aligner in people with Surface Roughness and Thickness Clear Aligner Sheat, run by Mansoura University at 1 site in Egypt.
Trial summary
aim of the study: to evaluate and compare the surface roughness (Ra, Rq, Rz), Vickers microhardness (VHN), and thickness of single-layer and multi-layer clear aligner sheets. material and methods: the study will be conducted on clear aligners fabricated from two commercial thermoplastic materials: single-layer (0.76… Read more about this study
- Who is it for?
- Ages 16 to 24 years
- Conditions the study is for
- Surface Roughness and Thickness Clear Aligner Sheat
- What is being tested?
- clear aligner
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteEgypt
- Study dates
- 1 Jan 2026to 1 Feb 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 16 to 24 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- Class I malocclusion with mild-moderate crowding (≤5 mm per arch).
- Full permanent dentition (excluding third molars).
- No restorations, caries, or attachments planned on the labial surface of upper/lower central incisors.
Who cannot join
- Systemic disease affecting saliva.
- Parafunctional habits (bruxism, nail-biting).
- Smoking.
- Pregnancy.
- Previous orthodontic treatment within 1 year.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Evaluation of Physical Changes in Single-Layer and Multi-Layer Clear Aligners After Thermoforming and Intraoral Wear
aim of the study: to evaluate and compare the surface roughness (Ra, Rq, Rz), Vickers microhardness (VHN), and thickness of single-layer and multi-layer clear aligner sheets.
material and methods: the study will be conducted on clear aligners fabricated from two commercial thermoplastic materials: single-layer (0.76 mm, ) and multi-layer (0.76 mm, ). Each material will be evaluated at three stages: before thermoforming, after thermoforming on 3D-printed casts, and after 2 weeks of intraoral wear.
Read more
Specimen Preparation For each group, specimens will be prepared at three stages: before thermoforming (T0), after thermoforming (T1), and after intraoral wear (T2). At T0, square-shaped specimens (approximately 5 × 5 mm) will be cut directly from the unused raw sheets. At T1 and T2, specimens of the same dimensions will be obtained from the mid-labial surface of the central incisor region of the thermoformed aligners, both immediately after thermoforming and after two weeks of intraoral wear. The full thickness of the material will be preserved in all specimens to ensure consistency across groups.
Outcomes:
Primary Outcome:
Surface Roughness (Ra):
Measured at three stages:
T0: Raw, unused sheet specimens (baseline) T1: After thermoforming on dental casts T2: After 2 weeks of intraoral use
Secondary Outcomes:
Hardness:
Measured at T0, T1, and T2. Tested using Vickers hardness method (ISO 6507 compliant).
Read the detailed description
aim of the study: To evaluate and compare the surface roughness (Ra, Rq, Rz), Vickers microhardness (VHN), and thickness of single-layer and multi-layer clear aligner sheets at three stages: before thermoforming, after thermoforming, and following intraoral wear.
material and methods: This in vivo study will be conducted on clear aligners fabricated from two commercial thermoplastic materials: single-layer (0.76 mm, ) and multi-layer (0.76 mm, ). Each material will be evaluated at three stages: before thermoforming (raw sheet), after thermoforming on 3D-printed casts, and after 2 weeks of intraoral wear. At each stage, specimens will be retrieved and tested for changes in mechanical properties, specifically surface roughness and hardness.
Study Design Type: A prospective, randomized, controlled, two-arm parallel clinical study
Design Details: participants will be randomly assigned to one of two groups:
Group A:
Upper arch: Multi-layer clear aligners Lower arch: Multi-layer clear aligners
Group B:
Upper arch: Single-layer clear aligners Lower arch: Single-layer clear aligners Baseline control: Unused aligner sheets of both types to serve as reference for measurements.
Sample Size Calculation: Sample size calculation was calculated using G*Power v3.1.9.7, a paired t-test with an expected effect size dz = 0.65 (based on Bucci et al.), α error = 0.05, and power = 80% indicated a minimum of 19 subjects. To simplify group allocation and ensure adequate power, the sample size was rounded up to 20 patients (10 patients in each group: single-layer vs. multi-layer).
Ethical Considerations:
Informed Consent: All participants (or their legal guardians) will sign an informed.
Appliance Fabrication and Treatment Protocol
- Digital impressions will be taken for all patients.
- Treatment setup will be performed with standardized staging: maximum 0.25-0.3 mm linear movement or 2-3° rotation per stage.
- Aligners will be fabricated by thermoforming using single and multilayer sheets (0.76 mm), cut and finished identically.
Specimen Preparation For each group, specimens will be prepared at three stages: before thermoforming (T0), after thermoforming (T1), and after intraoral wear (T2). At T0, square-shaped specimens (approximately 5 × 5 mm) will be cut directly from the unused raw sheets. At T1 and T2, specimens of the same dimensions will be obtained from the mid-labial surface of the central incisor region of the thermoformed aligners, both immediately after thermoforming and after two weeks of intraoral wear. The full thickness of the material will be preserved in all specimens to ensure consistency across groups.
Outcome Measures:
Primary Outcome:
Surface Roughness (Ra):
Measured at three stages:
T0: Raw, unused sheet specimens (baseline) T1: After thermoforming on dental casts T2: After 2 weeks of intraoral use Assessed using contact profilometry. Roughness defined as the arithmetic average surface deviation (Ra, in µm).
Secondary Outcomes:
Hardness:
Measured at T0, T1, and T2. Tested using Vickers hardness method (ISO 6507 compliant). Higher VHN values indicate greater resistance to indentation and deformation.
Thickness Change:
Measured at T0, T1, and T2. Evaluated using a digital micrometer or 3D scanning system. Calculated as the difference in thickness between the original sheet, thermoformed aligners, and post-use aligner
- Being tested
- clear aligner
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
clear alignerDevice
Appliance Fabrication and Treatment Protocol
- Digital impressions will be taken for all patients.
- Treatment setup will be performed with standardized staging: maximum 0.25-0.3 mm linear movement or 2-3° rotation per stage.
- Aligners will be fabricated by thermoforming using single and multilayer sheets (0.76 mm), cut and finished identically.
| Study group | Role | What they receive |
|---|---|---|
| Multi-layer clear aligners | Experimental | clear aligners fabricated from thermoplastic materials: multi-layer (0.76 mm). the material will be evaluated at three stages: before thermoforming (raw sheet), after thermoforming on 3D-printed casts, and after 2 weeks of intraoral wear. At each stage, specimens will be retrieved and tested for changes in mechanical properties, specifically surface roughness and hardness.
Baseline control: Unused aligner sheets of both types to serve as reference for measurements. Receives: Device: clear aligner |
| Single-layer clear aligners | Experimental | clear aligners fabricated from thermoplastic materials: single-layer (0.76 mm) . the material will be evaluated at three stages: before thermoforming (raw sheet), after thermoforming on 3D-printed casts, and after 2 weeks of intraoral wear. At each stage, specimens will be retrieved and tested for changes in mechanical properties, specifically surface roughness and hardness.
Baseline control: Unused aligner sheets of both types to serve as reference for measurements. Receives: Device: clear aligner |
What is being measured
The primary outcome is the main question the study is designed to answer.
surface roughness of clear aligner
evaluate and compare the surface roughness of single-layer and multi-layer clear aligner sheets at three stages: before thermoforming, after thermoforming, and following intraoral wear.
Quantitative evaluation of the arithmetic mean surface roughness (Ra) using profilometer
Measured: 2 weeks
Secondary outcomes (2)
microhardness of clear aligner
evaluate and compare the microhardness of single-layer and multi-layer clear aligner sheets at three stages: before thermoforming, after thermoforming, and following intraoral wear.
Quantitative evaluation of surface microhardness using the Vickers hardness test.
Measured: 2 weeks
thickness change of clear aligner
evaluate and compare the thickness of single-layer and multi-layer clear aligner sheets at three stages: before thermoforming, after thermoforming, and following intraoral wear.
Thickness will be measured using a calibrated digital caliper with an accuracy of ±0.01 mm
Measured: 2 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Mar 2026
- Study start1 Jan 2026
- Primary completion1 Jan 2027 (estimated)
- Study completion1 Feb 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Surface Roughness and Thickness Clear Aligner SheatStudies 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- Mansoura University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07449598
- Sponsor's protocol ID
- MS.25.11.85
- Status last verified
- Dec 2025
- First submitted
- 15 Feb 2026
- Last updated
- 4 Mar 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 4 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of Physical Changes in Single-Layer and Multi-Layer Clear Aligners After Thermoforming and Intraoral Wear
- ClinicalTrials.gov ID
- NCT07449598
- Acronym / sponsor ID
- MS.25.11.85
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 20 participants (actual)
- Lead sponsor
- Mansoura UniversityUniversity, hospital or other
- Study start
- 1 Jan 2026 (actual)
- Primary completion
- 1 Jan 2027 (estimated)
- Study completion
- 1 Feb 2027 (estimated)
- First posted
- 4 Mar 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.
aim of the study: to evaluate and compare the surface roughness (Ra, Rq, Rz), Vickers microhardness (VHN), and thickness of single-layer and multi-layer clear aligner sheets.
material and methods: the study will be conducted on clear aligners fabricated from two commercial thermoplastic materials: single-layer (0.76 mm, ) and multi-layer (0.76 mm, ). Each material will be evaluated at three stages: before thermoforming, after thermoforming on 3D-printed casts, and after 2 weeks of intraoral wear.
Specimen Preparation For each group, specimens will be prepared at three stages: before thermoforming (T0), after thermoforming (T1), and after intraoral wear (T2). At T0, square-shaped specimens (approximately 5 × 5 mm) will be cut directly from the unused raw sheets. At T1 and T2, specimens of the same dimensions will be obtained from the mid-labial surface of the central incisor region of the thermoformed aligners, both immediately after thermoforming and after two weeks of intraoral wear. The full thickness of the material will be preserved in all specimens to ensure consistency across groups.
Outcomes:
Primary Outcome:
Surface Roughness (Ra):
Measured at three stages:
T0: Raw, unused sheet specimens (baseline) T1: After thermoforming on dental casts T2: After 2 weeks of intraoral use
Secondary Outcomes:
Hardness:
Measured at T0, T1, and T2. Tested using Vickers hardness method (ISO 6507 compliant).
Detailed description
aim of the study: To evaluate and compare the surface roughness (Ra, Rq, Rz), Vickers microhardness (VHN), and thickness of single-layer and multi-layer clear aligner sheets at three stages: before thermoforming, after thermoforming, and following intraoral wear.
material and methods: This in vivo study will be conducted on clear aligners fabricated from two commercial thermoplastic materials: single-layer (0.76 mm, ) and multi-layer (0.76 mm, ). Each material will be evaluated at three stages: before thermoforming (raw sheet), after thermoforming on 3D-printed casts, and after 2 weeks of intraoral wear. At each stage, specimens will be retrieved and tested for changes in mechanical properties, specifically surface roughness and hardness.
Study Design Type: A prospective, randomized, controlled, two-arm parallel clinical study
Design Details: participants will be randomly assigned to one of two groups:
Group A:
Upper arch: Multi-layer clear aligners Lower arch: Multi-layer clear aligners
Group B:
Upper arch: Single-layer clear aligners Lower arch: Single-layer clear aligners Baseline control: Unused aligner sheets of both types to serve as reference for measurements.
Sample Size Calculation: Sample size calculation was calculated using G*Power v3.1.9.7, a paired t-test with an expected effect size dz = 0.65 (based on Bucci et al.), α error = 0.05, and power = 80% indicated a minimum of 19 subjects. To simplify group allocation and ensure adequate power, the sample size was rounded up to 20 patients (10 patients in each group: single-layer vs. multi-layer).
Ethical Considerations:
Informed Consent: All participants (or their legal guardians) will sign an informed.
Appliance Fabrication and Treatment Protocol
- Digital impressions will be taken for all patients.
- Treatment setup will be performed with standardized staging: maximum 0.25-0.3 mm linear movement or 2-3° rotation per stage.
- Aligners will be fabricated by thermoforming using single and multilayer sheets (0.76 mm), cut and finished identically.
Specimen Preparation For each group, specimens will be prepared at three stages: before thermoforming (T0), after thermoforming (T1), and after intraoral wear (T2). At T0, square-shaped specimens (approximately 5 × 5 mm) will be cut directly from the unused raw sheets. At T1 and T2, specimens of the same dimensions will be obtained from the mid-labial surface of the central incisor region of the thermoformed aligners, both immediately after thermoforming and after two weeks of intraoral wear. The full thickness of the material will be preserved in all specimens to ensure consistency across groups.
Outcome Measures:
Primary Outcome:
Surface Roughness (Ra):
Measured at three stages:
T0: Raw, unused sheet specimens (baseline) T1: After thermoforming on dental casts T2: After 2 weeks of intraoral use Assessed using contact profilometry. Roughness defined as the arithmetic average surface deviation (Ra, in µm).
Secondary Outcomes:
Hardness:
Measured at T0, T1, and T2. Tested using Vickers hardness method (ISO 6507 compliant). Higher VHN values indicate greater resistance to indentation and deformation.
Thickness Change:
Measured at T0, T1, and T2. Evaluated using a digital micrometer or 3D scanning system. Calculated as the difference in thickness between the original sheet, thermoformed aligners, and post-use aligner
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Multi-layer clear aligners | Experimental | Device: clear alignerclear aligners fabricated from thermoplastic materials: multi-layer (0.76 mm). the material will be evaluated at three stages: before thermoforming (raw sheet), after thermoforming on 3D-printed casts, and after 2 weeks of intraoral wear. At each stage, specimens will be retrieved and tested for changes in mechanical properties, specifically surface roughness and hardness. Baseline control: Unused aligner sheets of both types to serve as reference for measurements. |
| Single-layer clear aligners | Experimental | Device: clear alignerclear aligners fabricated from thermoplastic materials: single-layer (0.76 mm) . the material will be evaluated at three stages: before thermoforming (raw sheet), after thermoforming on 3D-printed casts, and after 2 weeks of intraoral wear. At each stage, specimens will be retrieved and tested for changes in mechanical properties, specifically surface roughness and hardness. Baseline control: Unused aligner sheets of both types to serve as reference for measurements. |
Who may qualify
- Ages
- 16 to 24 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (3 listed)
- Class I malocclusion with mild-moderate crowding (≤5 mm per arch).
- Full permanent dentition (excluding third molars).
- No restorations, caries, or attachments planned on the labial surface of upper/lower central incisors.
Key exclusion criteria (5 listed)
- Systemic disease affecting saliva.
- Parafunctional habits (bruxism, nail-biting).
- Smoking.
- Pregnancy.
- Previous orthodontic treatment within 1 year.
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 |
|---|---|---|
| clear alignerAppliance Fabrication and Treatment Protocol * Digital impressions will be taken for all patients. * Treatment setup will be performed with standardized staging: maximum 0.25-0.3 mm linear movement or 2-3° rotation per stage. * Aligners will be fabricated by thermoforming using single and multilayer sheets (0.76 mm), cut and finished identically. | Device | Multi-layer clear aligners, Single-layer clear aligners |
Primary outcome
surface roughness of clear aligner
Time frame: 2 weeks
evaluate and compare the surface roughness of single-layer and multi-layer clear aligner sheets at three stages: before thermoforming, after thermoforming, and following intraoral wear. Quantitative evaluation of the arithmetic mean surface roughness (Ra) using profilometer
2 secondary outcomes
microhardness of clear aligner
Time frame: 2 weeks
thickness change of clear aligner
Time frame: 2 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Mar 2026.
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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing clear aligner in people with Surface Roughness and Thickness Clear Aligner Sheat, run by Mansoura University at 1 site in Egypt.
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 5 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: under way, not looking for participants, as of the sponsor's last update on 4 Mar 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 Egypt. 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?
This study is still under way. Results are not available in the source record yet.
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?
surface roughness of clear aligner (time frame: 2 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 4 Mar 2026.