While acids are known to erode tooth enamel, alkalis too can have a damaging effect on our pearly whites, researchers from Sahlgrenska Academy at the University of Gothenburg have shown.
The Swedish study, conducted at the Department of Occupational and Environmental Medicine at the Sahlgrenska Academy, found that substances with high pH values can destroy parts of the organic content of the tooth, leaving the enamel more vulnerable.
"The study shows that exposure to alkaline substances can result in damaged teeth, but that the process is different to that caused by exposure to acidic drinks or acidic industrial vapours," said Fabian Taube, occupational hygienist and one of the researchers behind the study.
The deteriorating effect of alkaline substances caught the researchers' attention after they observed occupational injuries from reconditioning of cars, owing to exposure to an alkaline degreaser that was sprayed onto various parts of the cars.
"Exposure to this substance damaged the surface of the teeth resulting in "flaked" enamel. This type of damage markedly increases the risk of caries and other dental damage," said Jorgen Noren, professor and senior dental officer at the Sahlgrenska Academy.
Occupational damage to teeth from exposure to alkaline substances is probably not as common as damage from acidic substances, but it becomes a problem when employers fail to inform employees of the risks or do not give them access to the right protective equipment," said Taube.
The study exposed extracted teeth to degreasers and other alkaline solutions.
Enamel samples were then examined with a scanning electron microscope and analysed using various spectroscopic methods.
The researchers found that organic material on the surface of the tooth dissolves rapidly.
The results indicate that the organic components of the enamel are also affected, as the enamel becomes more porous.
"However, we were not able to show that alkaline substances change the composition of the minerals that constitute the main component of enamel. In that sense, it differs from the effects of exposure to acids," said Taube.
The study has been published in the Journal of Dentistry.