Pain is different for each person, according to Howard Hughes Medical Institute (HHMI) senior vice president and chief scientific officer Dr. David Clapham (HHMI). It’s painful in the extreme. In addition, he and an international team of experts have discovered how teeth detect the cold and have identified the chemical and cellular components involved. Research has shown that in both mice and humans, tooth cells called odontoblasts possess cold-sensitive proteins that sense temperature changes. The research team announced the discovery on March 26, 2021, in the journal Science Advances. Signals that originate from these cells are eventually sent to the brain and provide a severe pain stimulus.
In this research, the author attempts to answer a longstanding home remedy question by explaining how an age-old home treatment alleviates toothaches. This Clove Oil includes a molecule that inhibits the “cold sensor” protein (a protein receptor present in the mouth that helps with the detection of temperature), according to German physiologist Katharina Zimmermann, who conducted the study at the University of Erlangen-Nuremberg. The more precisely a medicine targets this sensor, the less likely you are to have dental sensitivity to cold, according to Zimmermann. The only way to prevent the onset of the disease is to identify the cause and/or cure the condition. Bacteria and acid cause teeth to decay because they cause the enamel, which is the hard, white coating of teeth, to be worn away. Once the enamel has worn away, pits or cavities appear. It has been estimated that over 2.4 billion individuals, or roughly a third of the world’s population, have untreated cavities in permanent teeth, which may cause considerable discomfort, including excessive cold sensitivity.
Though scientists have presented many theories on how teeth may perceive the cold, no one understood for sure how teeth worked. It is thought that tiny canals within the teeth store fluid that moves as the temperature changes. It seems that nerves have some kind of sensitivity to this movement, which may be used to help assess whether a tooth is hot or cold, some experts believe. Clapham, a neurobiologist at Janelia Research Campus for HHMI, points out that this notion could not be completely eliminated, since there was no data to back it up. Tooth movement and tooth biology are challenging to research because of the fluid movement that is involved. Scientists have to go through the toughest component in the human body: the enamel, followed by the even more challenging dentin. However, they are working to avoid shattering the tooth’s fragile pulp and the blood vessels and nerves that are contained inside it. This condition is called traumatic zerfasis. In this case, the entire tooth “may simply disintegrate.”
When Zimmerman, Clapham, and their colleagues began their research, they didn’t intend to focus on teeth. They conducted their research on ion channels, the microscopic structures inside cells’ membranes that function like tiny locks. Once it detects a signal — whether it be a chemical message or a change in temperature, for example — the channels close or open up and allow ions to flow into the cell. This produces an electrical pulse that begins in one cell and is repeated across all other cells. The information is rapidly transferred in this method, and it is very important in brain, heart, and other tissues.
About fifteen years ago, while Zimmermann was a postdoc in Clapham’s lab, the researchers found that TRPC5, an ion channel termed, was especially sensitive to low temperatures. The researchers was unable to identify the location of TRPC5’s cold-sensing capacity, even though TRPC5 was known to exist. The thing that caused their skin to shrivel was not the skin itself. As far as the mice without the ion channel were concerned, they were still able to perceive the cold, according to the researchers who published a paper on the matter in the Proceedings of the National Academy of Sciences in 2011.
Zimmermann concludes: “It went downhill from then,” he adds. During lunch one day, the crew was sitting around debating the issue when one of them suddenly had the solution. ” He then said, ‘Is there any other part of the body that responds to the temperature? Zimmermann speaks of. The solution was the teeth. An up-and-coming theory claims that TRPC5 is more prominent in individuals with periodontal disease, as revealed by Dr. Jochen Lennerz, a general pathologist from Massachusetts General Hospital, who identified it after reviewing specimens from human adults with periodontal disease.
When the researchers built an experimental mouse set up in which they could use TRPC5 to identify cold, they found the receptor did indeed operate as a cold sensor. Rather of splitting a tooth apart and just evaluating the cells in a dish, Zimmermann’s team looked at the whole system, which include the jawbone, teeth, and the nerve clusters around the teeth. As an ice-cold solution was applied to the tooth, the researchers was able to monitor brain activity. When applied to normal mice, this cold drop ignited nerve activity, showing that the tooth was reacting to the cold. In mice missing TRPC5, and in teeth treated with a substance that inhibited the ion channel, TRPC5 was not found to be expressed. That was a critical piece of evidence in regards to the ion channel’s ability to sense cold, Zimmermann adds. In the end, it turned out that another ion channel the scientists examined, TRPA1, seemed to have a role to play as well.
By pinpointing the cell type that the TRPC5 protein dwells in, the research was able to locate the TRPC5 protein to a particular cell type called the odontoblast, which is found between the pulp and dentin. If you have a dentin- or dentine-exposed tooth, biting into a popsicle might set off a chain of events leading to a cascade of pain receptors called TRPC5-packed cells firing off a “ow!”-type signal to the brain.
As a result, that specific experience has not been as well investigated as other sciences, according to Clapham. He explains that tooth discomfort is a subject that individuals may not think relevant, but it is in fact a very significant one that has a wide impact. To support his claim, Zimmermann illustrates the lengthy process that this team has taken to arrive at this finding. That instance, figuring out the function of a certain molecule or cell is challenging, she explains. A excellent research project might take a long time to complete.
Citation: Howard Hughes Medical Institute. (2021, March 26). How teeth sense the cold. ScienceDaily. Retrieved June 6, 2021 from http://www.sciencedaily.com/releases/2021/03/210326151348.htm