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Oral Health Research Supporting Your Practice

Oral Health Research: Neutrophils Break Down Dentin and Cured Composite Resin

Following decades of research indicating that bacteria are responsible for tooth decay, the need for fillings and restorations, a new study, conducted by a number of University of Toronto oral health researchers and titled Human neutrophils degrade methacrylate resin composites and tooth dentin, is now pointing to a long-ignored culprit: neutrophils.

A type of white blood cell, neutrophils have up until now been best known for fighting inflammation. However, the research team has shown that the body’s immune system itself may be causing tooth decay and failing composite and other restorations. 

The Research

Building on a theory proposed 50-years ago by John Gabrovsek, in the Cleveland Clinic, and published in the Journal of Dental Research (1970), the research team used neutrophils isolated from blood to coat parts of extracted teeth and cured composite resin. Within the body, neutrophils reach the mouth via the gums and roots of the teeth. Then, they measured the level of teeth degradation at intervals of 2, 4, 24, and 48 hours and the degradation of cured composite resin degradation at intervals of 48 and 96 hours.

Within a few hours, researchers found dentin and the cured composite resin had sustained damage.

According to the study co-author, Dr. Michael Glogauer, “We can actually see them breaking down using electron microscopy.”

The team’s research also confirms the breakdown of by-products can only come from neutrophils. The reason? When bacteria is present in the mouth, neutrophils are activated and release “attack” enzymes. These enzymes attack mouth bacteria creating acids that degrade teeth and resins in the process.  

Study co-author, Dr. Yoav Finer, explained that “On their own, neutrophils are incapable of causing damage to the teeth. They [neutrophils] don’t have acid, so they can’t do much to mineralized tooth structures.”

What’s Next?

Today, the team is setting their sights on isolating the type of enzymes that damage teeth and finding ways to control or limit the damage caused by neutrophils, for example using mouth rinse.

Read the article or learn more about this research.


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1 Comment

  1. Dr Paul Belzycki June 15, 2019

    Every peer-review study comparing composite to amalgam comes to the same conclusion. Amalgam outperforms and outlasts resin as a filling material. And yet the use of amalgam is in decline because of the market pressures that “white is right”.

    In addition, modern culture tolerates planned, or for that matter, unplanned, obsolescence. The young generation does not value “built to last” but is acculturated to embrace “shiny and bright” as direct result of cellphone consumerism. The urge to dispose of a perfectly good device in a year or two for one that is more slick. Durability and craftsmanship is no longer held in esteem.

    It would be interested to run the same experiment comparing amalgam/dentine interface.

    The results of this study and other like it, is why us conscientious practitioners call it comPOOHsite resin.



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