Tooth deformation in extracted molars in
response to thermal stimuli
Authors :
- Pairoj Linsuwanont DDS, Grad Dip, MDSc, PhD
- Joseph Palamara PhD
- Harold Messer PhD
Abstract :
Objective This study investigated patterns of tooth deformation in response to immersion in hot and
cold water, and attempted to correlate the measured dimensional change with calculated values based
on coefficients of thermal expansion.
Materials and methods The extent of cuspal deformation and strains within dentine were assessed in
extracted human molars, in response to immersion in hot and cold water. Cuspal displacement was
measured using an extensometer attached to the buccal and lingual cusps, and strains on the pulpal
dentine surface were measured using strain gauges attached to the occlusal pulpal surface. Temperature
change was monitored with thermocouples. Tooth crowns were immersed in hot (80°C) or cold (2°C)
water for 5 seconds
Results Cuspal displacement and dentinal strain were greater, and occurred more rapidly, in response
to heat than to cold. Thermal strain was detected on the pulpal surface of dentine before any temperature
change occurred, and was much greater than calculated values based on thermal expansion or
contraction alone.
Conclusion Patterns of deformation of the tooth crown are complex, and involve not only thermal
expansion/contraction but also tooth flexure resulting from temperature gradients across tooth structure.
(CU Dent J. 2012;35:39-48)
Keywords :
deformation; teeth; thermal contraction; thermal expansion; thermal stimulus
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