The National Institutes of Health has suggested that tooth decay is the most prevalent chronic disease. Researchers have now discovered a promising method to regrow nonliving hard tissue, and also lessen or even eliminate pain associated with tooth decay.
Janet Moradian-Oldak, a professor at the Herman Ostrow School of Dentistry of USC, has investigated methods to regrow tooth enamel for the past two decades. The process is especially tricky because unlike bone, mature enamel cannot rejuvenate, as tooth enamel is a nonliving tissue.
Moradian-Oldak said, "Matrix metalloproteinase-20, an enzyme found only in teeth, chops up amelogenin proteins, which facilitate organized enamel crystal formation. MMP-20 clears the way for hard material to usurp vacated space. MMP-20 is released at a very early stage of enamel formation. MMP-20 chops up proteins during the crystallization of enamel. Together with other enzymes, it gets rid of 'sludge' so the enamel making cells in the body can add more mineral and make enamel, the hardest bioceramic in the human body."
Another study revealed that an amelogenin-chitosan hydrogel could repair early tooth decay by growing an enamel-like layer that reduces lesions by up to 70%.
Qichao Ruan, lead author of the hydrogel study and a postdoctoral research associate in the Center for Craniofacial Molecular Biology at USC, said, "Recognizing MMP-20's function in biomineralization is one of the first steps to learning how dental enamel forms in nature. The findings regarding MMP-20 not only help us to further understand the mechanisms of enamel formation but [they] also can be applied in the design of novel biomaterials for future clinical applications in dental restoration or repair."
The Food and Drug Administration is yet to approve the enamel regrowing gel.
Moradian-Oldak said, "One day people may be able to use an overnight mouth guard or teeth strips saturated with hydrogel to regrow enamel-like substances and reduce teeth sensitivity. Finding the right fix products such as toothpaste and mouthwash containing fluoride and casein phosphopeptide-amorphous calcium phosphate promote remineralization of initial enamel lesions; however, they need to be used regularly and are more of a tire patch than a real solution."
Moradian-Oldak said, "The gel plugs up the problem so people do not feel pain. It, however, fills the cracks and holes with an enamel-like substance. In the United States, 92% of adults aged 20 to 64 have had dental decay in their permanent teeth. Grinding teeth at night, gum recession and the disappearance of enamel over a lifetime due to demineralizing acidic food and drink are all common problems people everywhere face."
Ruan said, "When tested in an environment that mimics an oral cavity's biochemical processes, the gel created a robust attachment, eliminating the threat of secondary cavities in the same spot. The gel could be more effective than traditional crowns, whose adhesion weakens over time. Besides biocompatibility and biodegradability, the gel has unique antimicrobial and adhesion properties that are important for dental applications."
The study is published in the Journal of Biomedical Engineering and Informatics.