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CariesPhase 3NCT07849270

New In Situ Model Design for Caries and Erosion

A Phase 3 study testing 0 ppm fluoride toothpaste, 1150 ppm fluoride toothpaste and Mandibular intraoral appliance in people with Caries and Erosive Tooth Wear, run by Indiana University at 1 site in United States.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

This study will test simultaneously and independently two novel in situ models, one for caries and one for erosive tooth wear (ETW), based on the simulation of these dental conditions on enamel specimens placed on 3D-printed mandibular appliances. Read more about this study

Who is it for?
Ages 18 to 65 yearsHealthy volunteers can take part
Conditions the study is for
Caries, Erosive Tooth Wear
What is being tested?
0 ppm fluoride toothpaste, 1150 ppm fluoride toothpaste and Mandibular intraoral appliance
Type of treatment
Medical device
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
12 participants
Where
1 siteUnited States
Study dates
3 Aug 2026to 29 Jan 2027
Phase
Phase 3
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 18 to 65 years
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • In order to participate subjects must:
  • Provide voluntary, written informed consent;
  • Be between 18 and 65 years old;
  • Understand and be willing, able and likely to comply with all study procedures and restrictions;
  • Be willing and capable of wearing a custom-made removable mandibular appliance 24 hours a day for three (3), three-week treatment periods;
  • Be in good medical and dental health with no active caries or periodontal disease; Note: subjects presenting at screening with caries may continue in the study if their carious lesions are restored prior to beginning treatment 1; and,
  • Have a salivary flow rate in the range of normal values (unstimulated whole saliva flow rate ≥ 0.2 mL/min; gum base stimulated whole saliva flow rate ≥ 0.8 mL/min);
  • Have an adequate number of teeth and space to accommodate the custom-made removable mandibular appliance, as per the study PI/study dentist's discretion.

Who cannot join

  • No subject may:
  • Be pregnant, intending to become pregnant during the study period or breast feeding;
  • Have any medical condition that could be expected to interfere with the subject's safety during the study period (including temporomandibular disorders);
  • Be taking antibiotics during the study period, or have taken antibiotics in the two weeks prior to the beginning treatment 1;
  • Participated in another clinical study or receipt of an investigational drug within 30 days of beginning treatment 1;
  • Be taking fluoride supplements, required to use a fluoride mouthrinse or have received a professional fluoride treatment in the two weeks preceding specimen placement; or,
  • Have a history of metal allergies.

Trial locations and contacts

1 site in 1 country.

United States1 site

  • Oral Health Research Institute of the Indiana University School of Dentistry

    Indianapolis, Indiana, 46202

Other trials in United States

About this study

Official title: Novel In Situ Caries and ETW Models Development: Safety and Validation Study

This study will test simultaneously and independently two novel in situ models, one for caries and one for erosive tooth wear (ETW), based on the simulation of these dental conditions on enamel specimens placed on 3D-printed mandibular appliances. Caries simulation will be done on the right side (color-coded blue) of the appliance, while ETW on the left side (color-coded red) and their outcomes evaluated independently. The study aims at testing the safety, compliance and F-efficacy (dose-response) of the models. The study will follow a double-blind, single-center, 3-way within-subject crossover design. Treatments will consist of dentifrices, or toothpastes, (1150 ppm F as sodium fluoride, 250 ppm F as sodium fluoride and 0 ppm F/Negative Control) used twice a day.

Read the detailed description

The proposed in situ models have been designed for the study of dental caries and ETW, and to overcome some limitations associated to the models used at the Oral Health Research Institute. It is based on the removable intraoral mandibular appliance, to be used by participants with at least 20 teeth in the mouth, and targeting a younger adult population. The construction of the intraoral appliance will take advantage of the recent technology, precision and cost-efficiency associated to intraoral digital scanners and 3D metal printers. Wearing these appliances should be comfortable, as they rest passively in the cheek pouch and do not interfere with the habitual intercuspation of the teeth and phonetics. The investigators hypothesize the proposed in situ caries and ETW models to provide adequate treatment response broadly similar to our established caries and erosion in situ models, while expanding their utility, allowing long-term use and maintaining high subject compliance.

After study screening procedures are complete at the first study visit, a custom removable intraoral mandibular appliance will be made for each participant who is eligible to enroll in the study. Participants may need to return to the research site several times for appliance "try-in" visits prior to beginning the study procedures. Once a comfortable, well fitting appliance has been made, participants will proceed to study procedures.

Participants will progress through three treatment periods (each approximately 21 days in length). Each treatment period will require 5 study visits and at-home study procedures:

  • Prior to each treatment period, participants will attend a dental cleaning visit where a dental cleaning and oral examination will occur. At the end of the dental cleaning visit, participants will be provided with a fluoride free toothpaste to use at home for 2-3 days prior to the treatment initiation visit.
  • At each treatment initiation visit, 4 tooth specimens will be placed in each side of the intraoral appliance. Impressions will be made and stored for analysis. Participants will be provided with the first assigned toothpaste and at-home supplies.
  • During each 21 day treatment period, participants will use one of three study toothpastes, containing different fluoride levels, for the study directed twice daily brushing. Participants will be exposed to all three study toothpastes, however the treatment order sequence will be randomly assigned.
  • During each 21 day treatment period, participants will wear the dental appliance 24 hours per day except during meals/snacks and during at-home study directed procedures. Twice daily, participants will remove and brush the appliance according to study-specific directions. Four times daily, participants will remove and complete appliance challenge tasks in which the left and right sides of the appliance will be soaked in different solutions for 5 minutes at a time. Participants will return for evaluation at approximately 7, 14 and 21 days after each treatment period is initiated.
  • At the completion of each treatment period, participants will repeat the dental cleaning, treatment initiation, and day 7, 14, and 21 post-treatment initiation visits until all three study toothpastes have been used.
Being tested
0 ppm fluoride toothpaste, 250 ppm fluoride toothpaste (dose-response control), 1150 ppm fluoride toothpaste, Mandibular intraoral appliance
Keywords
cavities, gum recession
Medical subject headings
Gingival Recession

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • 0 ppm fluoride toothpasteDrug

    Toothpaste containing 0 ppm fluoride (F)

  • 250 ppm fluoride toothpaste (dose-response control)Drug

    Toothpaste containing 250 ppm fluoride, as NaF (sodium fluoride)

  • 1150 ppm fluoride toothpasteDrug

    Marketed toothpaste product containing 1150 ppm fluoride, as NaF (sodium fluoride)

  • Mandibular intraoral applianceDevice

    After impressions of both dental arches are taken, a mandibular appliance consisting of a 3D-printed metal frame and acrylic buccal flanges (blue on the right and red on the left) will be made. The appliance will be tested and adjusted for optimal fit and comfort before the experimental phase of the study. At each testing period, 4 gauze-covered 4-millimeter round partially demineralized human enamel specimens will be placed in the right buccal acrylic flange (blue, caries) side of the mandibular appliance and 4 sound human enamel specimens previously mounted on 3 millimeter round metal holders will be placed on the other acrylic flange (red, ETW) side of the same appliance. Subjects will wear their appliance 24 hours a day, except during study procedures, meals/snacks, and drinking (e.g. milk, juice, sports drinks, tea, etc.) except water.

Study groups in NCT07849270
Study groupRoleWhat they receive
0 ppm F toothpastePlacebo comparatorParticipants will use toothpaste containing 0 ppm fluoride.
Receives: Drug: 0 ppm fluoride toothpaste; Device: Mandibular intraoral appliance
250 ppm F toothpasteActive comparatorParticipants will use toothpaste containing 250 ppm fluoride.
Receives: Drug: 250 ppm fluoride toothpaste (dose-response control); Device: Mandibular intraoral appliance
1150 ppm F toothpasteActive comparatorParticipants will use toothpaste containing 1150 ppm fluoride.
Receives: Drug: 1150 ppm fluoride toothpaste; Device: Mandibular intraoral appliance

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Mean Percent Surface Microhardness (SMH) Recovery

    Description: The SMH test will be used to assess changes in the mineral status of partially demineralized enamel specimens. SMH will be measured using a Wilson 2100 Hardness Tester.

    The extent of remineralization will be calculated based on the Gelhard et al. method of %SMH recovery = (D1-R)/(D1-B) x 100 where:

    B = indentation length (µm, micrometer) of sound enamel specimen at baseline D1 = indentation length (µm) after in vitro demineralization R = indentation length (µm) after intra-oral exposure.

    Measured: Days 14 and 21 of each of the three consecutive treatment periods (each treatment period is 21 days)

  2. Surface Loss

    Measurements of enamel surface wear respective to the metal holder reference surfaces will be made on impressions of the specimens taken at baseline and after 7, 14 and 21 days of study. The impression of each specimen will be carefully cut with the aid of a scalpel and positioned on the profilometer with double adhesive tape for the scan. The parameters for the scan of both specimens and impressions will consist of step size set at 0.02 mm and number of steps at 200, in both x and y directions. The total area scanned will be 3 mm x 3 mm round specimens. With the use of dedicated software, the depth of the treated area will be calculated based on the reference surfaces. A 3-point height tool will be applied. Profile scans generated from impressions will be inverted (using the software) before analysis, in order to provide outcome data of surface loss (micrometers).

    Measured: Days 14 and 21 of each of the three consecutive treatment periods (each treatment period is 21 days)

Secondary outcomes (6)

  1. Mean Enamel Fluoride Uptake

    The Sakkab et al. microdrill enamel biopsy technique will be used to analyze the fluoride content of the partially demineralized enamel specimens. The amount of fluoride-uptake by enamel will be calculated based on the amount of fluoride divided by the area of the enamel cores and expressed as µg F/cm2.

    Measured: Days 14 and 21 of each of the three consecutive treatment periods (each treatment period is 21 days)

  2. Mean Net Acid Resistance

    To test whether the dentifrice imparts acid resistance to the enamel after 14 and 21 days of intra-oral exposure, a second in vitro demineralization will be repeated on the enamel specimens. SMH will be then evaluated by placing 5 indentations 100µm to the right of the indentations placed in situ remineralization. The %NAR will be calculated by the Corpron et al. method of % Net Acid Resistance = [(D1-D2) / (D1-B)] * 100 where:

    B: Indentation length (µm) of sound enamel at baseline D1: Indentation length (µm) after first in vitro demineralization D2: Indentation length (µm) after second in vitro demineralization

    Measured: Days 14 and 21 of each of the three consecutive treatment periods (each treatment period is 21 days)

  3. Mean Comparative Acid Resistance

    This measure takes a different approach to understanding whether the enamel formed during remineralization is more resistant to acid than the original enamel. Using the data from the two enamel specimens, the equation used will compare explicitly the reduction in SMH brought by the first and second acid challenges:

    • Comparative Acid Resistance = [(D2-R) / (D1-B)] * 100 B: Indentation length (µm) of sound enamel at baseline R: Indentation length (µm) of enamel after in situ remineralization D1: Indentation length (µm) after first in vitro demineralization D2: Indentation length (µm) after second in vitro demineralization

    Measured: Days 14 and 21 of each of the three consecutive treatment periods (each treatment period is 21 days)

  4. Transervse Microradiography (TMR) - Integrated Mineral Loss

    Sections, approximately 100 µm in thickness, will be cut parallel to the orientation cut, after completion of the SMH analysis, using a Silverstone-Taylor Hard Tissue Microtome (Scientific Fabrications Laboratories, USA). The sections will be placed in the TMR-D system and X-rayed at 45 kV and 45 mA at a fixed distance for 12 s. An aluminum step wedge will be X-rayed under identical conditions. The digital images will be analyzed using the TMR software v.3.0.0.18. Sound enamel will be assumed to be 87% v/v mineral.

    Lesions will be analyzed after in situ demineralization to calculate Integrated Mineral Loss (∆Z): [(lesion depth x 87) - area under the curve*]. *Area under the curve which relates volume % mineral at distances from the specimen surface with respect to section thickness.

    Measured: Days 14 and 21 of each of the three consecutive treatment periods (each treatment period is 21 days)

  5. Transverse Microradiography (TMR) - Lesion Depth

    Sections, approximately 100 µm in thickness, will be cut parallel to the orientation cut, after completion of the SMH analysis, using a Silverstone-Taylor Hard Tissue Microtome (Scientific Fabrications Laboratories, USA). The sections will be placed in the TMR-D system and X-rayed at 45 kV and 45 mA at a fixed distance for 12 s. An aluminum step wedge will be X-rayed under identical conditions. The digital images will be analyzed using the TMR software v.3.0.0.18. Sound enamel will be assumed to be 87% v/v mineral.

    Lesions will be analyzed after in situ demineralization to calculate Lesion Depth (L): 83% mineral i.e. 95% of the mineral content of sound enamel.

    Measured: Days 14 and 21 of each of the three consecutive treatment periods (each treatment period is 21 days)

  6. Transverse Microradiography (TMR) - Maximum mineral density at the surface-zone

    Sections, approximately 100 µm in thickness, will be cut parallel to the orientation cut, after completion of the SMH analysis, using a Silverstone-Taylor Hard Tissue Microtome (Scientific Fabrications Laboratories, USA). The sections will be placed in the TMR-D system and X-rayed at 45 kV and 45 mA at a fixed distance for 12 s. An aluminum step wedge will be X-rayed under identical conditions. The digital images will be analyzed using the TMR software v.3.0.0.18. Sound enamel will be assumed to be 87% v/v mineral.

    Lesions will be analyzed after in situ demineralization to calculate maximum mineral density at the surface-zone (SZmax).

    Measured: Days 14 and 21 of each of the three consecutive treatment periods (each treatment period is 21 days)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted30 Sep 2026
  2. Study start3 Aug 2026
  3. Primary completion29 Jan 2027 (estimated)
  4. Study completion29 Jan 2027 (estimated)

Resources

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 3
Primary purpose
Basic science
Allocation
Randomised
Intervention model
Crossover
Model description
Each participant will be randomly assigned to a treatment order sequence. Each participant will complete all three treatment regimens, one treatment regimen in each of the three treatment periods.
Masking
Triple blind
Who is masked
Participant, Investigator, Outcomes assessor
Enrolment
12 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07849270
Sponsor's protocol ID
31100
Status last verified
Sep 2026
First submitted
31 Aug 2026
Last updated
30 Sep 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
Yes
Individual data sharing
No

Publications

  • Rikvold PT, Kambourakis Johnsen K, Leonhardt D, Mollebjerg A, Nielsen SM, Skov Hansen LB, Meyer RL, Schlafer S. A New Device for In Situ Dental Biofilm Collection Additively Manufactured by Direct Metal Laser Sintering and Vat Photopolymerization. 3D Print Addit Manuf. 2023 Oct 1;10(5):1036-1045. doi: 10.1089/3dp.2022.0009. Epub 2023 Oct 10.

    PubMed 37886402

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing 0 ppm fluoride toothpaste, 1150 ppm fluoride toothpaste and Mandibular intraoral appliance in people with Caries and Erosive Tooth Wear, run by Indiana University at 1 site in United States.

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 8 inclusion and 7 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 30 Sep 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 United States. 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. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

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?

Mean Percent Surface Microhardness (SMH) Recovery (time frame: Days 14 and 21 of each of the three consecutive treatment periods (each treatment period is 21 days)). The study lists 2 primary outcomes in all. 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 NCT07849270, which also lists 1 linked publication.

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 30 Sep 2026.

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