Determination of Pulp vitality by pulse oximeter based on:
Pulse oxymetry-

Based on Beer Lambert law
Utilization of a probe that transmits red (640 mm) and infrared light
Photo detector as a receptor site
Different absorption ability of light by oxygenated and deoxygenated haemoglobin leads to changes in the amount of light differently absorbed by the vascular bed before reaching the photo detector.
Beer's law.
Pascal's law.
Doppler law.
Poisslues law.