Monitoring de- and remineralisation of enamel in vitro using an infrared reflectance meter.

The aim of this study was to design and investigate the use of an inexpensive method of monitoring the progress of demineralisation and subsequent remineralisation in artificial carious lesions. A small infrared (IR) reflectance meter was built which illuminated a 4 mm x 4 mm area on the buccal surface of a tooth and measured the reflected IR intensity. Repeated measurements were taken over a period of 25 days, during which the enamel surface was exposed to demineralising and subsequently remineralising solutions. Thirty-six teeth were studied under a variety of de- and remineralising conditions. It was observed that the IR specular reflectance of the tooth surfaces decreased with time during lesion formation and increased with time during remineralisation. It is suggested that the decrease in IR specular reflectance during demineralisation and the increase during remineralisation are a result of continuous changes in the crystals at the enamel surface during these processes.