# Impact of the Enamel Cleaning Procedure during Debonding on Endodontium Temperature: In Vitro Tests
## 3 Results  
The proposed methods of data acquisition and analysis allowed for the assessment of tooth temperature during the mechanical enamel cleaning procedure. The optimal procedure for cleaning the enamel should not increase the temperature of the teeth in order to avoid a critical increase in pulp tissue temperature. Analysis of thermovision data indicated that there were clear differences in the pulp chamber temperature obtained during enamel cleaning using water cooling and without it. In order to determine the quantitative dynamics of tooth temperature changes under the influence of mechanical cleaning, thermographic data were fitted to exponential functions. Due to the fact that the hard tissue of teeth is made up of two components (dentin and enamel) a two-exponential model was used. However, matching to the one-exponential function did not increase the matching error, which is why further analyses were conducted with a one-exponential model. Figures 1 and 2 show examples of matching curves for tooth temperature changes during mechanical cleaning. Figure 1: An example of the relationship between the premolar pulp chamber temperature (T) and the time (t) of polishing for a procedure performed with water cooling. Figure 2: An example of the relationship between the premolar pulp chamber temperature (T) and the time (t) of polishing for a procedure performed without water cooling. A clear difference was recorded in the parameters of the fitting function to the exponential model for water cooling and non-cooling treatments. These differences related to the time constant \(\tau\) for the exponential function determining the dynamics of temperature rise in the polished teeth. For tooth cleaning without water cooling, the time constant \(\tau\) of temperature rise is 31.29 and 33.83 for incisors and premolars, respectively (Table 1), while for water cooling, the time constant \(\tau\) is 40.65 and 43.70 (Table 2), respectively for incisors and premolars. The obtained parameters of the adjustment function to the exponential function indicate that water cooling not only causes the obtained maximum pulp chamber temperature to be lower, but also the dynamics of temperature rise is slower. However, a clear difference in the maximum temperature measured on the pulp-dentin border of the teeth was recorded for teeth cleaned without cooling and with water cooling. In the first case, the maximum recorded temperature was 50.11 \({}^{\circ}\)C in a time interval of 60 s, while in the case of water cooling, it was about 7 \({}^{\circ}\)C less in the same period of time. For exponential functions describing the dynamics of temperature drop, no clear differences were recorded for the treatment procedure with water cooling and without water cooling (Tables 3 and 4). In addition, no statistically significant differences in the dynamics of temperature changes were registered for different types of teeth (incisors and premolars). It is worth emphasizing that the adaptation to the one-exponential function indicates that the teeth, despite the fact that they consist of two clearly different layers (enamel and dentin), can be treated as an object with uniform thermokinetic properties, and matching the dynamics of temperature changes to the two-exponential function does not minimize matching errors. \begin{table}
\begin{tabular}{c c c c c} \hline  & \(\mathbf{K_{0}}\) & \(\mathbf{K_{1}}\) & \(\mathbf{\tau_{1}}\) & \(\mathbf{\delta}\) \\ \hline Incisors & \(11.23\pm 3.54\) & \(6.75\pm 4.00\) & \(40.65\pm 5.77\) & \(0.001\pm 0.0005\) \\ Premolars & \(12.41\pm 4.41\) & \(7.14\pm 3.87\) & \(43.70\pm 6.41\) & \(0.001\pm 0.0005\) \\ \hline \end{tabular}
\begin{tabular}{c} K0—constant; K1—amplitude of exponential functions; \(\tau\)1—time constant; \(\delta\)-fitting error. \\ \end{tabular}
\end{table} 
Table 1: Fitting parameters of the one-exponential function for temperature growth during polishing without water cooling, showing the average for all tested samples (n = 32).