USC University of Southern California

Herman Ostrow School of Dentistry of USC

Ostrow School of Dentistry Study Highlighted by NIDCR

An Ostrow School of Dentistry study on the relationship between an important protein and tooth enamel strength has been featured on the NIDCR Web site this month.

Associate Professor Michael Paine and Research Associate Rodrigo Lacruz led the team exploring the role played by the protein NBCe1 in the formation of strong, properly mineralized tooth enamel. “The Sodium Bicarbonate Cotransporter (NBCe1) is Essential for Normal Development of Mouse Dentition” appeared in the August 6, 2010 issue of the Journal of Biological Chemistry.

Two years ago, the researchers first demonstrated that enamel-forming cells, or ameloblasts, produce NBCe1, a protein that transports bicarbonate and buffers pH levels in the extracellular environment around the ameloblasts. This study showed that the mice lacking the ability to produce NBCe1 grew teeth that had weak, under-mineralized enamel.

While it’s a well established fact that a diet rich in acidic foods, including citrus, can damage the enamel of existing teeth, this project showed that the cellular environment surrounding a developing tooth prior to eruption must also be pH-controlled to ensure proper enamel formation, Paine and Lacruz reported.

The results have implications for human patients as well. Individuals suffering from a rare syndrome called proximal renal tubular acidosis, which is caused by a defect in the gene for NBCe1, also appear to have tooth enamel that is weak and lacking proper mineralization.

The Sodium Bicarbonate Cotransporter (NBCe1) is Essential for Normal Development of Mouse Dentition, Lacruz RS, Nanci A, White SN, Wen X, Wang HJ, Zalzal SV, Luong VQ, Schuetter VL, Conti PS, Kurtz I, and Paine ML.  J Bio Chem, Aug 6, 2010;285(32),24432.