In Vivo Investigation of Initial Stages of Enamel Erosion

Study Overview
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Brief Summary
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This exploratory study is designed to help develop a clinical model to measure the earlier stages of dietary acid medicated enamel loss. The study will use fluoride as positive control to explore the validity of this design.

Official Title
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Study to Investigate the Initial Stages of Enamel Erosion in Vivo

Conditions
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Tooth Erosion

Intervention / Treatment
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* Other: Sodium fluoride + potassium nitrate
* Other: Potassium nitrate


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Demonstrates understanding of the study procedures, restrictions and willingness to participate as evidenced by voluntary written informed consent and has received a signed and dated copy of the informed consent form. Aged at least 18 years Good general and mental health with, in the opinion of the investigator or medically qualified designee no clinically significant and relevant abnormalities in medical history or upon oral examination. Absence of any condition that would impact the participant's safety or well-being, or affect the participant's ability to understand and follow study procedures and requirements. Two anterior maxillary teeth, without signs of toothwear or exposed dentine, facial restorations, abutments for fixed or removable partial dentures, full crowns or veneers, orthodontic bands or cracked enamel that would interfere with the study evaluations. Exclusion Criteria: Pregnant or breast feeding women Known or suspected intolerance or hypersensitivity to the study materials (or closely related compounds) or any of their stated ingredients Participation in another clinical study (including cosmetic studies) or receipt of an investigational drug within 30 days of the screening visit Recent history (within the last year) of alcohol or other substance abuse Presence of a disease or medication which in the opinion of the investigator, will impact on assessments Gross periodontal disease, treatment of periodontal disease (including surgery) within 12 months of screening, scaling or root planning within 3 months of screening Surface irregularities, discoloration due to trauma, restorations and hypo or hyperplasic areas which, in the opinion of the investigator or dental assessor, would prevent accurate impressions and grading Daily doses of a medication which, in the opinion of the investigator, could impact the assessment, for example acidic medications Any condition that would impact on the subject's safety or wellbeing or affect the individual's ability to understand and follow study procedures and requirements

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Test Product<br>Subjects will apply a full ribbon of dentifrice and brush their teeth for 1 timed minute using a wetted toothbrush, swish the resulting slurry around the mouth for 30 seconds making sure it contacts the selected teeth, spit out slurry and rinse mouth for 10 seconds with water. | Other: Sodium fluoride + potassium nitrate<br>* Marketed toothpaste containing 1450ppm fluoride as sodium fluoride and 5% potassium nitrate<br>|
| Placebo Comparator: Reference Product<br>Subjects will apply a full ribbon of dentifrice and brush their teeth for 1 timed minute using a wetted toothbrush, swish the resulting slurry around the mouth for 30 seconds making sure it contacts the selected teeth, spit out slurry and rinse mouth for 10 seconds with water. | Other: Potassium nitrate<br>* Experimental toothpaste containing 5% potassium nitrate<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change From Pre-acid Challenge (Baseline) Tooth Impression Grading Score Immediately Following an Acid Challenge | The impressions of the tooth surface were analysed using scanning electron microscopy (SEM) to investigate changes in the enamel surface topography to determine degree of early stage enamel erosion. Interrogation of the tooth surface via impressions using SEM followed by visual image analysis was used to investigate the enamel surface topography. The Images were graded as follows: - No signs of surface erosive wear (no evidence of the lock and key structure) - Early signs of erosive surface changes - Mild signs of erosive surface changes (early signs of the lock and key structure). - Moderate signs of erosive surface changes - Severe signs of erosive surface changes (lock and key structure and enamel pits) X - Not evaluable | Baseline, 30 minutes post dietary acid challenge | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change From Pre-acid Challenge (Baseline) Tooth Impression Grading Score Following 2 Hours Post Acid Challenge. | The impressions of the tooth surface were analysed using scanning electron microscopy (SEM) to investigate changes in the enamel surface topography to determine degree of early stage enamel erosion. Interrogation of the tooth surface via impressions using SEM followed by visual image analysis was used to investigate the enamel surface topography. The Images were graded as follows: - No signs of surface erosive wear (no evidence of the lock and key structure) - Early signs of erosive surface changes - Mild signs of erosive surface changes (early signs of the lock and key structure). - Moderate signs of erosive surface changes - Severe signs of erosive surface changes (lock and key structure and enamel pits) X - Not evaluable | Baseline, 2 hours post acid challenge | 
| Change From Pre-acid Challenge (Baseline) Tooth Impression Grading Score Following 4 Hours Post Acid Challenge | The impressions of the tooth surface were analysed using scanning electron microscopy (SEM) to investigate changes in the enamel surface topography to determine degree of early stage enamel erosion. Interrogation of the tooth surface via impressions using SEM followed by visual image analysis was used to investigate the enamel surface topography. The Images were graded as follows: - No signs of surface erosive wear (no evidence of the lock and key structure) - Early signs of erosive surface changes - Mild signs of erosive surface changes (early signs of the lock and key structure). - Moderate signs of erosive surface changes - Severe signs of erosive surface changes (lock and key structure and enamel pits) X - Not evaluable | Baseline, 4 hours post acid challenge | 
| Change From Pre-acid Challenge (Baseline) Tooth Impression Grading Score Following 7 Hours Post Acid Challenge | The impressions of the tooth surface were analysed using scanning electron microscopy (SEM) to investigate changes in the enamel surface topography to determine degree of early stage enamel erosion. Interrogation of the tooth surface via impressions using SEM followed by visual image analysis was used to investigate the enamel surface topography. The Images were graded as follows: - No signs of surface erosive wear (no evidence of the lock and key structure) - Early signs of erosive surface changes - Mild signs of erosive surface changes (early signs of the lock and key structure). - Moderate signs of erosive surface changes - Severe signs of erosive surface changes (lock and key structure and enamel pits) X - Not evaluable | Baseline, 7 hours post acid challenge | 
| Change From Baseline of Salivary Calcium Concentration at 30 Mins Post Dietary Acid Challenge | Saliva stored at 0 - 20°C was used for determining calcium concentration | Baseline, 30 mins post dietary acid challenge | 
| Change From Baseline of Salivary Calcium Concentration 7 Hours Post Dietary Acid Challenge | Saliva stored at 0 - 20°C was used for determining calcium concentration | Baseline, 7 hours post dietary acid challenge | 
| Change From Baseline of pH Measurement at 30 Mins Post Dietary Acid Challenge | Saliva stored at 0 - 20°C was used for determining pH | Baseline, 30 mins post dietary acid challenge | 
| Change From Baseline of pH Measurement 7 Hours Post Dietary Acid Challenge | Saliva stored at 0 - 20°C was used for determining pH | Baseline, 7 hours post dietary acid challenge | 
| Change From Baseline in Buffering Capacity at 30 Mins Post Dietary Acid Challenge | Saliva was collected and stored at 0 - 20°C. A Saliva-check Buffer Kit was used to determine the buffer capacity. The colourimetric assay yielded a coloured pattern on a paper diagnostic using a 0-12 scale where 0-5 was deemed to be very low, 6-9 was deemed low and 10-12 was deemed normal-high. | Baseline, 30 mins post dietary acid challenge | 
| Change From Baseline in Buffering Capacity 7 Hours Post Dietary Acid Challenge | Saliva was collected and stored at 0 - 20°C. A Saliva-check Buffer Kit was used to determine the buffer capacity. The colourimetric assay yielded a coloured pattern on a paper diagnostic using a 0-12 scale where 0-5 was deemed to be very low, 6-9 was deemed low and 10-12 was deemed normal-high. | Baseline, 7 hours post dietary acid challenge |