Monitoring Pressure and Temperature in Dental Cavity Through Micro Sensors

Objectives: We introduced a new technique for real-time monitoring of a pressure and a temperature in a dental pulp cavity with a micro fiber-optic pressure-sensor and an ultra-fine thermo-couple. During dental treatment, we obtained resultant increases in the pressure and the temperature.
Methods: We developed experimental setup, in which a micro fiber-optic pressure-sensor and an ultra-fine sheathed-thermo-couple are settled in a dental pulp cavity. During the dental treatment, the pressure and the temperature are monitored in real-time through the sensors. The diameter of the pressure-sensor is 800μm. The specifications are 0-340kPa in pressure range, 0.2% of full scale in resolution, ±0.5% of full scale in accuracy, -20 to 150°C in operating temperature, and 200kHz in sampling rate. The diameter of the thermo-couple is 150μm. The specifications are -200 to 1000°C in temperature range, 25msec in response time, and -200 to 1000°C in operating temperature. Next, the top of dentin settled in the setup was ground with a round router bar (CA12a) attached on dental electric motor without water, and the parameters inside the cavity were monitored in real-time.
Results: When the dentin of central incisor was ground with a round bar (CA12a) at 20,000rpm without water, the pressure in the cavity increased by 1kPa after 20 seconds. The temperature increased by 0.5°C after 30 seconds gradually.
Conclusions: Through the new method proposed in this report, the quantitative evaluation of the pain during the dental treatment was possible. As dental hydro-dynamic theory mentions, the pressure stimulus propagated into the cavity through the dental tubules directly, and the processing heat conducted gradually into the cavity.