1. Brendan Eckardt, Ukrit Thamma, Himanshu Jain
Materials Science and Engineering
Superior treatment of hypersensitive teeth
by a novel bioactive glass
Acknowledgement(s):
David and Lorraine Freed Undergraduate Research Symposium, Lehigh University
Bill Muschock, William Heffner, Thomas Simonton, Jadon Sargent, IMI-NFG (NSF)
Procedure
• Bovine teeth were provided by Dentsply
• The teeth were cored with a diamond drill and
mounted in epoxy
• Enamel was ground away to expose dentine
and presence of exposed tubules was checked
using LOM
• Glass powder was mixed with water and the
slurry was applied to the tooth using a
dentist’s hand-piece provided by Dentsply
Abstract
Tooth sensitivity in humans can occur when the protective enamel layer covering a
tooth deteriorates, exposing nerve endings to fluids within the mouth. One way of
treating sensitivity is using glass particles to create a temporary protective layer in
places where the enamel has worn away. The purpose of this investigation was to
compare the efficacy of a 70-30 calcium-silica nanoporous glass developed here at
Lehigh to a traditional glass used in commercial toothpaste. Success of each glass in
preventing sensitivity was measured by comparing effective coverage of the tooth and
durability of the layer when submerged in Coke. Wear tests to simulate the effects of
brushing were also planned, but were not carried out. Preliminary results suggest that
the 70-30 glass provides better coverage of the tooth and therefore should be better for
preventing tooth pain. Acid test results showed no difference between glasses. More
rigorous and quantitative methods are suggested for future work.
Conclusions and Future Work
• 70-30 glass provided better occlusion of dentine tubules than the 45S5
glass used in NovaMin
• Samples submerged in coke for 5 and 15 minutes showed no change for
either glass
• The use of imaging software is suggested in order to provide quantitative
comparisons of occlusion
• Application of glass paste and brush testing should be performed using a
computer-guided rail system in order to better control experimental
variables
Procedure (continued)
• Acid tests were conducted by submerging treated samples in Coke and
placing in an incubator at 37°C for 5 and 15 minutes
• After testing, all samples were fully dried and examined in the SEM
Introduction
Tooth anatomy consists of an enamel layer, under which lies a region of packed
tubules known as dentine. These dentine tubules are directly above nerves inside of the
tooth. Removing the enamel layer allows fluids in the mouth to travel through the
dentine and reach the nerves, causing pain.
Toothpastes designed to treat hypersensitivity use glass powder to cover the dentine
openings, protecting the sensitive nerves underneath. The glass can be thought of as
creating a temporary enamel layer that is renewed every time you brush your teeth.
The glass powder used was judged based on occlusion of dentine tubules and
durability in acidic and wear conditions.
Figure 1. Anatomy of a human tooth
Figure 2. Incisor and mounted core
Results
Occlusion
Visual inspection of SEM micrographs show that the 70-30 glass
provided better occlusion of dentine tubules than the 45S5 glass found in
Sensodyne. However, in order to corroborate these initial results and provide
a more quantitative comparison between the two, the images should be
examined using imaging software with a control taken from the same tooth.
Acid Tests
Acid tests resulted in no noticeable change after 5 or 10 minutes for
45S5 or 70-30 glass. The only visible effect was a discoloration of the
sample as Coke made its way into the dentine layer. Testing with stronger
acids or for longer periods of time may result in some change, but would be
impractical for everyday considerations of dental hygiene.
Toothbrushing Simulation
Figure 3. SEM micrographs of exposed dentine tubules with no glass (left),
NovaMin 45S5 glass (middle), and 70-30 nanoporous glass (right).
Figure 4. Apparatus for
proposed brush tests
Wear tests were not performed due
to inability to control:
• Lubrication
• Application force
• Application site
• Bristle location in relation to
dentine