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

AbstractTooth 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

IntroductionTooth 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

ResultsOcclusion

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