Evaluation of Secondary Thermal Hyperalgesia Resulting from Pulpal Inflammation in Patients with Symptomatic Irreversible Pulpitis

IntroductionInflammation can lead to hyperalgesia and allodynia by activation or sensitization of peripheral and central nervous system neurons. This study aimed to assess the occurrence of secondary thermal hyperalgesia in patients with symptomatic irreversible pulpitis (SIP).MethodsThe cold sensitivity test (visual analog scale) was performed for the tooth with SIP, its adjacent sound tooth, the same sound tooth in the opposite jaw, and the contralateral sound tooth in the opposite quadrant of the same jaw. Next, the tooth with SIP underwent root canal treatment, and 3 weeks later, after complete elimination of pain, the teeth underwent cold sensitivity testing again.ResultsA total of 64 patients, including 41 women and 23 men 18–65 years old, were evaluated in this study. The response to the cold sensitivity test significantly decreased in the tooth with SIP (P < .001), its adjacent sound tooth (P < .001), and the same sound tooth in the opposite jaw (P = .004) but not in the contralateral sound tooth in the opposite quadrant of the same jaw (P = .45) after endodontic treatment. No significant difference was noted between men and women in the groups (P > .05).ConclusionsHypersensitivity to cold test due to pulpal inflammation can also result in exaggerated response of the adjacent sound tooth and the same tooth in the opposite jaw to cold sensitivity test; these observations can be explained by the central and peripheral sensitization mechanisms.