Researchers at Northumbria University in the UK have found direct evidence for the first time that smoking causes permanent damage to teeth.
This discovery not only deepens people’s understanding of the effects of smoking, but also provides a new tool for forensic and archaeological research.
The study, published recently in the journal PLOS One, revealed that smokers will leave long-lasting and recognizable “marks” deep in their teeth, even after quitting for many years.
These marks are hidden in a layer of hard tissue called “cementum” at the root of the teeth. Cementum is deposited year by year with age, similar to the growth rings of trees.
The researchers’ original research purpose was to estimate the age through the growth rings of cementum, which could be used for forensic identification.
But after analyzing 88 teeth from modern dental patients and archaeological sites, they unexpectedly found that some teeth had abnormal damage in the growth rings, which was closely related to smoking behavior.
The data showed that about 70% of former smokers showed signs of damaged cementum structure, while the proportion of current smokers was 33%. In contrast, only 3% of non-smokers had similar damage to their teeth.
More interestingly, the research team found that the cementum of ex-smokers tends to be thicker than that of continuing smokers. Scientists speculate that this is because the body tries to repair the cementum after quitting smoking, forming a denser deposit that covers up the early damage.
“For the first time, we have confirmed that it is possible to determine whether a person has a history of smoking simply by observing the growth ring structure in the teeth,” said Ed Schwalbe, associate professor at Northumbria University.
“This is extremely rare in non-smokers, but more common in smokers or former smokers.”
The study recruited 46 patients who were undergoing tooth extraction treatment and provided a total of 70 teeth, along with detailed medical history and smoking records.
The researchers specifically mentioned a tooth from a 58-year-old subject. By analyzing its cementum structure, they determined that the damage occurred between the ages of 22 and 41, which was completely consistent with his smoking history.
In addition to modern samples, the research team also collaborated with the University of Leicester to analyze 18 archaeological teeth from 1776 to 1890.
Some teeth even retain stains and gaps from pipe smoking. The pattern of cementum destruction is exactly the same as the traces in the teeth of modern smokers.
This study not only confirms the permanent impact of smoking on tooth structure, but also opens up new directions for health research of historical populations.
“We can use these records in teeth to restore the lifestyles of people in the past, especially when understanding tobacco use habits in historical periods,” Schwalbe said.
Sarah Inskip, a co-author of the study and an archaeologist at the University of Leicester, said that these findings provide a new path for studying the long-term effects of tobacco on health in the past few centuries.
She is currently leading an interdisciplinary project called “Tobacco, Health and History”, focusing on the impact of smoking on human health between 1600 and 1900.
This method of judging smoking behavior through cementum rings, formally known as “cell-free extrafibrous cementum (AEFC) analysis”, was mainly used in the past to estimate the age of death, pregnancy and major disease time points. This is the first time it has been used to identify the history of tobacco use.
Research assistant Valentina Perrone added: “We visually and statistically compared cementum deposition in smokers, ex-smokers and non-smokers to identify abnormal patterns associated with smoking.
It is well known that smoking is closely related to periodontitis and tooth loss. Now we can clearly see that these damages leave a permanent “archive” in the microstructure of the teeth.”
This breakthrough not only provides important insights into the fields of dentistry and public health, but will also have a far-reaching impact in forensic identification, historical disease analysis and other fields.