Method: Approval of the Ethics Committee at Ponta Grossa State University was obtained: protocol #255,945. Premolars (#14 and #24) requiring extraction for orthodontic reasons from 8 volunteers, ranging from 12 to 30 years, received infiltrative and intraligamental anesthesia. The teeth (n=15) were isolated using rubber dam and a small, occlusal preparation was made, under air-water spray, until a minute pulp exposure was attained. The sterile probe from a wireless, NIST-traceable, temperature acquisition system (Temperature Data Acquisition - Thermes WFI, Physitemp, Clifton, NJ, USA) was inserted directly into the coronal pulp. Once the probe was properly positioned and stable, real-time temperature data were continuously acquired every 0.2s, for approximately 25 min. Data were expressed in degree Celsius (°C) at initial probe insertion, and after 25-min. Results were subjected to statistical analysis as described below (α=0.05).
Result: The initial temperature reading demonstrated significantly lower pulp temperature values (31.8±1.5°C) than after 25-min (35.3±0.7°C): 2-tailed, paired t-test, p=0.0000). The 95% confidence interval for the initial temperature ranged from 31.0 to 32.6°C and from 35.0 to 35.7°C after 25 minutes. In each case, a slow and gradual temperature increase was observed after probe insertion until the pulp temperature reached a plateau after approximately 20 min of analysis.
Conclusion: Consistent coronal human, in vivo temperature values were measured that were slightly, but significantly below that of body temperature. When considering the extent of intrapulpal temperature rise, it is important to know the physiologic, baseline value from which increases are determined.