Abstract: The present invention relates to the use of pulse oximeter technology, and particularly, a pulse oximeter-like probe for diagnosing the pulpal vitality and vascular integrity of a subject tooth. The present invention does not require a reaction by the patient to pain caused by stimulation of a tooth. Thereby, the present invention is not as susceptible to false negatives or positives as were past methods for determining tooth vitality which were dependent on obtaining a neuronal response. As described herein, lack of neuronal response does not always indicate pulpal death. Both the apparatus and method of the present invention allow an immediate, objective diagnosis of tooth vitality without inducing painful stimulation.