Why do wisdom teeth cause problems and pain, often requiring oral surgery to remove? Western Washington University professors may have found some evidence that could help solve this mystery.
Associate Professor Tesla Monson and Assistant Professor Marianne Brasil have worked in museums in Africa, Europe, Asia, and the United States to complete research related to facial structure in a group of primates, including baboons and their relatives.
Brasil and Monson have collaborated on multiple projects for more than a decade. On April 15, 2025, they published their findings on primate facial structure and its relationship to modern human teeth.
The two collected various measurements from monkey skeletons to capture the shape of the monkeys’ heads.
“It’s really fun to work on these types of projects because they stem from things we’re curious about,” Brasil said.
Brasil and Monson were invited to contribute their research to a special issue of the journal Frontiers in Ecology and Evolution.
The baboon skeletons they observed had relatively long faces. Scientific consensus varies on how long faces affect their teeth.
In contrast, humans have evolved a flatter face over the past five million years. Around the same time, human wisdom teeth also became very small. There are still questions in the scientific community as to why.
“Our study suggests that the long faces of baboons are related to their long third molars, which in humans we call wisdom teeth,” Monson said.
The data they collected, Monson said, begs the question: Are smaller wisdom teeth in humans related to flatter faces?
This evidence supports the theory that humans’ small and often problematic wisdom teeth are associated with an evolutionary flattening of the face. However, Monson said it’s just one clue of evidence, and experts in other fields have more research to do.
“We call it comparative evidence because it’s farther down the lineage, but primates share the same basic genetic and developmental pathways,” Monson said. “So by looking at how they work in other animals, we can learn what to look for in humans.”
Tina Gilbert, a dental assistant at Simpson and Coyner Family Dentistry in Gig Harbor, talked about wisdom teeth and why they sometimes need to be removed.
Gilbert said removing wisdom teeth isn’t mandatory. She often sees older patients who still have their wisdom teeth intact. However, if wisdom teeth aren’t growing properly, they need to be removed.
“If wisdom teeth are partially erupted, meaning they’re partially coming out of the gum, it’s usually recommended that they be removed,” Gilbert said. “That’s because wisdom teeth are very difficult to clean. It’s easy for food to get stuck between the tooth and the gum, which can cause infection.”
Brasier said that when doing studies like this, she and Monson review each other’s work before sending it out for peer review. This is done so that any major flaws that might come up when the reviewers review it are addressed. They review each other based on who the lead author of the study is.
Monson was the lead author on this particular study. Brassier said her contribution to the study was helping to build the dataset that the research relied on.
Brassier and Monson did not conduct this research alone; they worked with labs in Western University’s Department of Anthropology. Monson runs the Primate Evolution Lab and Brassier runs the Paleoanthropology Lab.
In the lab, students work with data as well as real monkey bones, gaining osteological and forensic experience.
Monson and Brassier’s research provides a platform for genetic researchers to study. Monson said their research will help other scientists find genes of interest.
“So it’s just a big collaborative effort, and ideally everyone in each field will come to the same conclusions based on their data,” Monson said.
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