The Effect of Experimental Dentifrices on Remineralization of Caries Lesions In-situ

Study Overview
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Brief Summary
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This study will evaluate the effect of experimental sodium fluoride-silica dentifrice formulations, with and without zinc, on remineralization of enamel in situ. Following the remineralization phase, the acid resistance of the new mineral formed will be assessed. Fluoride uptake during the remineralization phase will also be measured.

Official Title
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The Effect of Experimental Dentifrices on Remineralization of Caries Lesions In-situ

Conditions
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Oral Hygiene

Intervention / Treatment
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* Drug: Sodium fluoride (1426 ppm)
* Drug: Sodium fluoride (1150 ppm)
* Drug: Sodium fluoride (250 ppm)
* Drug: Sodium fluoride (1426 ppm) + zinc base A
* Drug: Sodium fluoride (1426 ppm) + zinc base B
* Drug: Fluoride (0 ppm)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Good general health with no clinically significant and relevant abnormalities of medical history or oral examination Participants with maxillary dental arch suitable for the retention of the palatal appliance Exclusion Criteria: Participants taking fluoride supplement Pregnant or breast-feeding women

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 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: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Sodium fluoride (1426 ppm)<br>Non-zinc, 1426ppm fluoride as sodium fluoride in a silica gel base | Drug: Sodium fluoride (1426 ppm)<br>* Non-zinc, 1426ppm fluoride as sodium fluoride in a silica gel base<br>|
| Experimental: Sodium fluoride (1150 ppm)<br>Non-zinc, 1150ppm fluoride as sodium fluoride in a silica gel base | Drug: Sodium fluoride (1150 ppm)<br>* Non-zinc, 1150ppm fluoride as sodium fluoride in a silica gel base<br>|
| Experimental: Sodium fluoride (250 ppm)<br>Non-zinc, 250ppm fluoride as sodium fluoride in a silica gel base | Drug: Sodium fluoride (250 ppm)<br>* Non-zinc, 250ppm fluoride as sodium fluoride in a silica gel base<br>|
| Experimental: Sodium fluoride (1426 ppm) + zinc base A<br>Zinc base A, 1426ppm fluoride as sodium fluoride in a silica gel base | Drug: Sodium fluoride (1426 ppm) + zinc base A<br>* Zinc base A, 1426ppm fluoride as sodium fluoride in a silica gel base<br>|
| Experimental: Sodium fluoride (1426 ppm) + zinc base B<br>Zinc base B, 1426ppm fluoride as sodium fluoride in a silica gel base | Drug: Sodium fluoride (1426 ppm) + zinc base B<br>* Zinc base B, 1426ppm fluoride as sodium fluoride in a silica gel base<br>|
| Placebo Comparator: Fluoride (0 ppm)<br>Non-zinc, 0ppm fluoride in a silica gel base | Drug: Fluoride (0 ppm)<br>* Non-zinc, 0ppm fluoride in a silica gel base<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage Surface Microhardness Recovery (% SMHR) | Changes in the mineral content of the four centrally-located enamel specimens were evaluated using the Surface Microhardness (SMH) Test. The SMH was measured using a Wilson 2100 Hardness Tester. The baseline SMH was determined prior to the in vitro acid challenge. SMH was determined again after the in vitro acid challenge, after the in situ remineralization test, and again after the second in vitro acid challenge. The extent of remineralization was calculated as the % recovery in SMH using the equation: % SMHR= [(D1-R)/(D1-B)]*100 Where B = indentation length (μm) of sound enamel at baseline; D1 = indentation length (μm) after first acid challenge; R = indentation length (μm) after in situ remineralization. | Baseline to 4 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Enamel Fluoride Uptake | The microdrill enamel biopsy technique was used to analyze the fluoride uptake by enamel. Each enamel specimen was mounted on the long axis of a drill attached to a microdrill and drilled to a depth of approximately 100 micrometer (μm) through the entire lesion (four cores per specimen). The enamel powder pooled from four drilling sample was then immediately analyzed for fluoride content using fluoride specific electrode and pH/ion meter. The amount of fluoride-uptake by enamel was calculated based on the amount of fluoride divided by the area of the enamel cores and expressed as microgram per square centimeter (μg/cm^2). | Baseline to 4 hours | 
| Percentage Net Acid Resistance (% NAR) | Changes in the mineral content of the four centrally-located enamel specimens were evaluated using the SMH Test. The SMH was measured using a Wilson 2100 Hardness Tester. The baseline SMH was measured prior to the in vitro acid challenge. SMH was measured again after the in vitro acid challenge, after the in situ remineralization test, and again after the second in vitro acid challenge. The % NAR was calculated using the equation: % NAR= [(D1-D2)/(D1-B)]*100 where B= Indentation length (μm) of sound enamel at baseline; D1= Indentation length (μm) after first acid challenge and D2= Indentation length (μm) after second acid challenge. | Baseline to 4 hours | 
| Percentage Comparative Acid Resistance (% CAR) | Changes in the mineral content of the four centrally-located enamel specimens were evaluated using the SMH Test. The SMH was measured using a Wilson 2100 Hardness Tester. The baseline SMH was measured prior to the in vitro acid challenge. SMH was measured again after the in vitro acid challenge, after the in situ remineralization test, and again after the second in vitro acid challenge. The % CAR was calculated using the equation: % CAR= [(D2-R)/(D1-B)]*100 where 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 acid challenge; D2= Indentation length (μm) after second acid challenge. | Baseline to 4 hours |