The purpose of this study is to compare the remineralization potential of an optimized fluoride dentifrice to a control fluoride dentifrice in an in situ caries model.
This will be a double blind, single center, 3-way crossover design study. Two to three days before the start of each treatment period the subjects will have their teeth cleaned to remove all accessible plaque and calculus and will be provided with a non-fluoride dentifrice to use until their next visit. At the beginning of each testing period, two gauze-covered 4 mm round partially demineralized bovine enamel specimens will be placed in the buccal surface of two posterior denture teeth (the specimen site may extend into the buccal flange area, if needed) of the same side of the partial denture. Once specimens are placed, subjects will wear their partial dentures twenty-four hours a day and use their assigned toothpaste twice daily, as instructed, until their next visit. Specimens will be removed after two weeks, and the subjects will undergo at least a four- to five-day washout period followed by another cleaning and two to three day lead in period. This process will be repeated until all subjects have used all three test products. Changes in the mineral content of the enamel specimens will be assessed using surface microhardness (SMH) and transverse microradiography (TMR). Enamel fluoride uptake (EFU) will be determined using the microdrill enamel biopsy technique. In addition, the net acid resistance (NAR) and the comparative acid resistance (CAR) of the demineralized enamel specimens will be determined.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
TRIPLE
Enrollment
52
• Each subject will use this product during one of the three treatment periods in the crossover study design.
• Each subject will use this product during one of the three treatment periods in the crossover study design.
• Each subject will use this product during one of the three treatment periods in the crossover study design.
Indiana University School of dentistry, Oral Health Research institute 415 Lansing Street
Indianapolis, Indiana, United States
Percent Surface Microhardness Recovery (%SMH Recovery)
The SMH test was used to assess changes in the mineral status of partially demineralized enamel specimens. %SMH Recovery = (D1-R)/(D1-B) ×100 B = indentation length (µm) of sound enamel specimen at baseline D1 = indentation length (µm) after in vitro demineralization R = indentation length (µm) after intra-oral exposure.
Time frame: at the end of each two-week treatment per
Enamel Fluoride Uptake (µg F/cm2)
The microdrill enamel biopsy technique will be used to analyze the fluoride content of the partially demineralized enamel specimens. Each enamel specimen will be mounted perpendicular to the long axis of a drill bit attached to a specially designed microdrill and drilled to a depth of \~100 µm through the entire lesion (four cores per specimen). The diameter of the drill hole will be determined using a calibrated microscope interfaced with an image analysis system. 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
Time frame: at the end of each two-week treatment period
Percent Net Acid Resistance
% Net Acid Resistance = \[(D1-D2) / (D1-B)\] \* 100 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
Time frame: at the end of each two-week treatment period
Percentage Comparative Acid Resistance
% 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
Time frame: at the end of each two-week treatment period
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Integrated Mineral Loss (∆Z)
∆Z= \[(lesion depth x 87) - area under the curve\*\] calculated using Transverse Microradiography software program
Time frame: at the end of each two-week treatment period
Lesion Depth (µm)
Lesion Depth - L (83% mineral i.e. 95% of the mineral content of sound enamel) determined using Transverse Microradiography software program
Time frame: at the end of each two-week treatment period
Maximum Mineral Density at the Surface-zone (SZmax)
SZmax was determined using Transverse Microradiography software program
Time frame: at the end of each two-week treatment period