A wireless system for continuous in-mouth pH monitoring

A first prototype of a Smart Orthodontic Bracket (SOB) for continuous in-mouth pH monitoring is presented in this paper. The SOB system uses an Iridium Oxide (IrOx) pH sensor with 68.8 mV/pH measured sensitivity. It is powered through Near Field Communications (NFC) using a smartphone from a distance of 3.5 cm. The system resolves pH variations as small as 0.15 within a wide range of pH. The system is encapsulated in bio-compatible epoxy resin and successfully used to measure the pH in saliva.