Project Summary/Abstract
Permanent tooth loss is a significant health issue in the United States. Approximately 25% of adults 60 years
and older have had complete tooth loss. In addition, nearly 70% of adults between the ages of 35-44 have lost
at least one permanent tooth, with the number of individuals suffering from tooth loss projected to remain
stable at approximately 9 million. Because of the detrimental effects associated with it, reducing tooth loss to
<20% of adults over the age of 65 became a national health objective in the year 2000. Loss of permanent
natural teeth negatively affects an individual’s diet and nutrition, and can substantially reduce quality of life and
self-image. Tooth loss also directly impacts essential daily functions including speech and chewing due to
altered or absent sensory feedback. Despite this, sensory processing of dentition remains incompletely
understood, as does neural plasticity following tooth loss, despite the fact that teeth are one of the most
commonly lost anatomical structures (through trauma, disease, or purposeful removal). This incomplete
understanding of the neural processing that underlies tooth sensation critically impedes the development of
novel strategies aimed at reducing the negative impact of tooth loss, and enhancing recovery from the lasting
debilitating effects which often follow.
Daily functions such as speech and chewing rely on distinguishing and combining cues from multiple sensory
modalities at once in order to guide accurate perception and drive appropriate behavioral responses. The
current proposal would be the first to examine: 1) how multiple sensory modalities (tactile, auditory, and visual)
are integrated at the neuronal level to enhance sensory perception related to craniofacial and periodontal
inputs, and 2) how multisensory neural circuits are reorganized following tooth loss. First, we will perform
detailed electrophysiological mapping of periodontal and craniofacial (tactile) projections to the cerebral cortex
of animal models. This cortical mapping will compare neuronal responses to tactile stimuli alone vs. responses
to multisensory stimulus combinations (i.e., more than one sensory modality, such as tactile + auditory).
Second, we will examine the multisensory cortical reorganization that results from tooth extraction. Altogether,
these studies will provide insight into: 1) the neural physiology underlying dental and craniofacial sensory
perception, 2) the role that additional sensory modalities play in dental and craniofacial sensation, and 3) the
neural plasticity caused by the loss of normal sensory inputs from the teeth that affects those suffering from
permanent tooth loss. These fundamental advances in the understanding of tooth sensation are essential for
driving future data-driven, novel therapeutic strategies aimed at reducing the negative impact of tooth loss, and
enhancing recovery from tooth loss, ultimately improving dental, oral, and craniofacial health in a large
proportion of the U.S. population.
