## 3 Results  
Figure 3 shows photographs of a standardized bone model specimen together with the 3D-printed surgical guide that was used in this study. Each bone was prepared for thermodynamic measurements by mounting the surgical template onto it and drilling the lateral holes used for inserting the thermocouples and the fixation pins. Although is not clearly visible from the photographs in Figure 3, the template bed did not rest perfectly on the bone models, thus permitting the evacuation of the irrigation fluid while drilling with the guide featuring internal cooling, as can be seen in Supplementary Video S1. The rise in temperature induced by drilling was measured for both surgical guide types, in each bone, at four locations, and for all drill sizes. Using 14 artificial bones, the measurements generated 336 independent thermodynamic data points. Representative heating curves are displayed in Figure 4. Here, each line represents the temperature measured near the osteotomy site at specific positions on the surgical guide. The three consecutive peaks on each curve correspond to the use of the three consecutive drills. The temperature rose sharply during the osteotomy, and the maximum values were used to calculate the temperature increments, \(\Delta\)T = T\({}_{\text{max}}\) - T\({}_{\text{baseline}}\). When the drill apex reached the target depth, drilling stopped and we moved to the next position. We continued this process until the largest drill was used on the final position. It can be observed in Figure 4 that osteotomies with the larger-diameter drill led to higher \(\Delta\)T values. This can be explained by the combined effect of two factors. First, the time between subsequent drills at the same position was insufficient for heat dissipation, so the local temperature did not return to the baseline value. Second, the edge of the final drill was closer to the neighboring thermocouple. Figure 4: Temperature curves recorded at four different regions (surgical guide pairs) during osteotomy. The top panel exemplifies measurements with the internally routed irrigation channel guide, while the bottom panel shows data from the classical guide. The examples were selected purposefully to include temperature recordings with higher variability, to illustrate the difficulties met while obtaining the thermodynamic data. Figure 3: Photographs of a standardized bone model and the 3D-printed surgical guide used in this study. The top-right panel shows the template mounted on the artificial bone specimen, whereas the bottom-right panel is a picture of the bone specimen prepared for measurements, with lateral holes drilled for inserting thermocouples and fixation pins. The examples plotted on the two panels of Figure 4 showcase the variability of the data recorded during the thermodynamic measurements. For example, in the top panel, the green curve corresponding to the third pair of guides (Region 3) exhibits overall slower rises during osteotomy and lower \(\Delta\)T compared to measurements in other regions. Most likely, this happened because, in this particular instance, the thermocouple tip was located farther from the drilling site than planned, or due to inadequate contact between the thermocouple and the adjacent bone. The bottom panel shows noisy data for the orange (Region 2) and red (Region 4) curves immediately after reaching the peak values. This could indicate that the thermocouples moved slightly during drill repositioning for the next osteotomy. Such variability is expected in this type of experimental design. Overlaid violin plots and box plots of the 336 independent determinations of \(\Delta\)T are shown in Figure 5. Here, individual data points are represented by circular markers. The width of the violin plots indicates the probability density function, with wider sections representing domains where more data points are clustered.