Details of dental wear revealed

October 08, 2019

The teeth of mammals experience constant wear. However, the details of these wear processes are largely unknown. Researchers at the University of Zurich have now demonstrated that the various areas of herbivores' teeth differ in how susceptible they are to dental wear, detailing an exact chronology.

"In our clinic, we regularly treat guinea pigs and rabbits with dental problems. We're therefore especially interested in finding out how exactly the changes to their teeth happen," says Jean-Michel Hatt, professor at the Clinic for Zoo Animals, Exotic Pets and Wildlife at the University of Zurich. The teeth of mammals are exposed to constant wear, but the exact details of this process have long been a mystery. Enamel is actually harder than the parts in the food that erode the teeth. In mammals, the relevant parts are mostly phytoliths, or "plant stones" - microscopic structures made of silica and often found in grass. "There's no consensus among dental researchers as to how phytoliths can actually erode tooth enamel," says Jean-Michel Hatt.

Hard and softer dental tissue

The surfaces of teeth in herbivores are not only made of enamel. In between the enamel ridges, there is the dentin tissue, which is softer. As a result of these varying degrees of hardness, the chewing surface in the teeth of horses, cattle or guinea pigs develops a surface akin to a grater - with hard ridges protruding from softer tissue. "There's very little research into how this softer dentin tissue reacts to abrasive food," says Hatt. Most dental researchers are interested in the tooth enamel.

Guinea pigs and bamboo

Working together with researchers from the Johannes Gutenberg University Mainz, Jean-Michel Hatt and his team carried out a feeding experiment with guinea pigs. They fed the animals three different diets during three weeks, namely fresh lucerne - which, like clover, contains no phytoliths - normal grass and bamboo leaves. Bamboo in particular has a high silica content. To observe the effects, the researchers used micro-computed tomography, a particularly precise 3D imaging technique that uses X-rays to see inside an object.

The findings gained in this way impressed even the researchers. "Even without knowing which animal I was surveying on screen, I was able to tell which diet it had been fed," says Louise Martin, doctoral candidate at the Clinic for Zoo Animals, Exotic Pets and Wildlife. "The animals that had been given bamboo had significantly shorter teeth." This was the case despite the fact that guinea pigs have continually growing molars. Taking a closer look, Martin found the decisive detail: The shorter teeth featured dentin surfaces that were disproportionately eroded. "The phytoliths attack the dentin, and once the enamel ridges are very exposed, they're no longer as stable and experience more wear." This is an effect that can likely only be observed well in systems with fast-growing teeth - in rodents, for example - and with extraordinarily abrasive types of food, such as bamboo.

Bamboo no food for herbivores

"Most people don't feed their herbivores bamboo," says Hatt, "and our findings show that they're right not to." But what about animals such as panda bears, whose diet consists exclusively of bamboo? "Panda bears are actually carnivores and as such don't have the ridged teeth typical of herbivores," explains Jean-Michel Hatt. "Their teeth are fully covered by enamel."
-end-


University of Zurich

Related Herbivores Articles from Brightsurf:

Researchers reveal switch used in plant defense against animal attack
UC San Diego researchers have identified the first key biological switch that sounds an alarm in plants when plant-eating animals attack.

More plant diversity, less pesticides
Increasing plant diversity enhances the natural control of insect herbivory in grasslands.

RUDN University mathematician refined the model of predator-prey relations in the wild
The traditional mathematical model of predator-prey relations in the wild does not take into account indirect nonlocal interactions.

Changing landscapes, changing diets
A new study led by Enquye Negash, a postdoctoral researcher in the George Washington University Center for the Advanced Study of Human Paleobiology, published this week in the journal Proceedings of the National Academy of Sciences documents dietary shifts in herbivores that lived between 1-3 million years ago in Ethiopia's Lower Omo Valley.

Herbivores, not predators, most at risk of extinction
One million years ago, the extinction of large-bodied plant-eaters changed the trajectory of life on Earth.

Herbivorous vertebrates may face most daunting extinction risk
Herbivores -- not predators -- may face a higher risk of extinction among mammals, birds, and reptiles, according to a new study of more than 44,000 living and extinct species.

Counteracting a legacy of extinctions
Now a new study, comparing the traits of introduced herbivores to those of the past, reveals that introductions have restored many important ecological traits that have been lost for thousands of years.

Pablo Escobar's hippos may help counteract a legacy of extinctions
When cocaine kingpin Pablo Escobar was shot dead in 1993, the four hippos in his private zoo in Colombia were left behind.

Reconstructing the diet of fossil vertebrates
Paleodietary studies of the fossil record are impeded by a lack of reliable and unequivocal tracers.

Shrewd savannah species choose friends with benefits on the African plains
For species trying to boost their chances of avoiding predation, it could be a classic case of 'it's not what you know, it's who you know that matters,' according to new research.

Read More: Herbivores News and Herbivores Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.