Faculty Bibliography

If one could be a patient repeatedly, every twenty-five years, starting in 1825, the evolution and comparison of dental care and dental practice would be historically meaningful. Such a time travel, as a perpetual patient through 200 years, is the purpose of this paper. The changes that occurred over 200 years provide a sense of the progress in treating patients and the transformation of a painful and dreaded experience to a highly sophisticated painless profession.

The COVID-19 pandemic caused by SARS-CoV-2 virus quickly spread globally, infecting over half a billion individuals, and killing over 6 million*. One of the more unusual symptoms was patients' complaints of sudden loss of smell and/or taste, a symptom that has become more apparent as the virus mutated into different variants. Anosmia and ageusia, the loss of smell and taste, respectively, seem to be transient for some individuals, but for others persists even after recovery from the infection. Causes for COVID-19-associated chemosensory loss have undergone several hypotheses. These include non-functional or destroyed olfactory neurons and gustatory receptors or of their supporting cells, disruption of the signaling protein Neuropilin-1, and disruption in the interaction with semaphorins, key molecules in the gustatory and olfactory axon guidance. The current paper will review these hypotheses and chart out potential therapeutic avenues.

Human taste cells are a heterogeneous population of specialized epithelial cells that are constantly generated from progenitor taste cells. Type I and type III taste cells express some neural markers, and studies have reported that direct innervation by neurons is not required for taste cell development. To our knowledge, no previous study has demonstrated that taste cells can differentiate into neuron-like cells or any other non-taste cell type. Here, for the first time, we describe a simple in vitro method that uses a serum-free neural induction medium to differentiate cultured physiologically functional primary human taste (HBO) cells into neuron-like cells in 2-3 wk with high efficiency. We verified neural attributes of these HBO-derived neuron-like with immunocytochemistry, single-cell calcium imaging, and DiI staining and examined cell morphology using transmission electron microscopy. Induced neuron-like cells demonstrated neuron-specific proteins, dendritic and axonal morphology, and networking behaviors. This technique will open new avenues for translational medicine, autologous cell therapy, regenerative medicine, therapy for neurodegenerative disorders, and drug screening.

Teaching history of dentistry and/or medicine in dental schools is not a priority today. A half a century ago it was part of a significant number of dental school curricula. As advances in science occurred and more demand on the curriculum were made, history of medicine and dentistry (HMD) was largely cast aside. In a recent survey of 393 dental programs in 100 countries on five continents, only 18.8% have a stand-alone course in HMD. Nearly half of the programs though have at least 1-2 hours of curriculum time devoted to HMD. When we consider a subset of the above survey, only 5% of dental schools in the US and Canada have a stand-alone course. The exclusion of HMD from current dental curricula is shortsighted. Teaching only current and state-of-the art aspects of dentistry is like showing a still image from the end of a movie without watching the rest.