# Bone Temperature Variation Using a 3D-Printed Surgical Guide with Internal Irrigation
## 3 Results  
The evolution of temperature variation over time as average of the twelve samples for each group is displayed in Figure 4.  
The largest temperature variation at Tc1 showed a median of 3.0 \({}^{\circ}\)C (IQR 2.4-3.4 \({}^{\circ}\)C) in Group 1, which was not statistically different than Group 2 (median 2.3 \({}^{\circ}\)C, IQR 1.4-3.7 \({}^{\circ}\)C, \(p_{adj}\) = 0.83), Group 3 (median 3.2 \({}^{\circ}\)C, IQR 2.9-6.2 \({}^{\circ}\)C; \(p_{adj}\) = 0.81), or Group 4 (median 2.0 \({}^{\circ}\)C, IQR 1.5-3.3 \({}^{\circ}\)C; \(p_{adj}\) = 0.83) (Figure 5 and Table S1).  
Among the secondary outcome measures, the largest temperature variation at Tc2 showed a median of 1.9 \({}^{\circ}\)C (IQR 1.5-3.2 \({}^{\circ}\)C) in Group 1, which was not statistically different than Group 2 (median 1.7 \({}^{\circ}\)C, IQR 1.2-2.5 \({}^{\circ}\)C; \(p_{adj}\) = 0.49), Group 3 (median 1.6 \({}^{\circ}\)C, IQR 1.0-3.4 \({}^{\circ}\)C; \(p_{adj}\) = 0.49) or Group 4 (median 2.0 \({}^{\circ}\)C, IQR 1.0-2.5 \({}^{\circ}\)C; \(p_{adj}\) = 0.49) (Figure 6 and Table S1).  
Figure 4: Mean temperature variation (\(\Delta\)T) over time. The initiation of each drilling sequence step is indicated as follows: (*) Cortical Perforator drill; (•) 2.0 mm; (•) 2.75 mm; (•) 3.00 mm; (\(\blacksquare\)) 3.25 mm twist drills.  
The largest temperature variation at Tc3 showed a median of 2.3 \({}^{\circ}\)C (IQR 1.8-3.5 \({}^{\circ}\)C) in Group 1, which was not statistically different than Group 2 (median 0.9\({}^{\circ}\)C, IQR 0.7-2.2 \({}^{\circ}\)C; \(p_{adj}\) = 0.15), Group 3 (median 2.0 \({}^{\circ}\)C, IQR 0.9-2.5 \({}^{\circ}\)C; \(p_{adj}\) = 0.15) or Group 4 (median 1.3 \({}^{\circ}\)C, IQR 0.6-2.1 \({}^{\circ}\)C; \(p_{adj}\) = 0.27) (Figure 6 and Table S1).  
Among the secondary outcome measures, the average temperature increment with respect to starting temperature is displayed in Figure 7 and Table S2. At Tc1, the average temperature increment showed a median of 1.0\({}^{\circ}\)C (IQR 0.7-1.6 \({}^{\circ}\)C) in Group 1, which was not statistically different than Group 2 (median 0.8 \({}^{\circ}\)C, IQR 0.5-1.1 \({}^{\circ}\)C; \(p_{adj}\) = 0.42), Group 3 (median 1.3 \({}^{\circ}\)C, IQR 0.8-2.3 \({}^{\circ}\)C; \(p_{adj}\) = 0.51) or Group 4 (median 0.8 \({}^{\circ}\)C, IQR 0.4-1.0 \({}^{\circ}\)C; \(p_{adj}\) = 0.48).  
At Tc2, the average temperature increment showed a median of 0.9 \({}^{\circ}\)C (IQR 0.7-1.2 \({}^{\circ}\)C) in Group 1, which was higher with respect to Group 2 (median 0.5 \({}^{\circ}\)C, IQR 0.4-0.9 \({}^{\circ}\)C; \(p_{adj}\) = 0.03) but was not statistically different than Group 3 (median 0.7 \({}^{\circ}\)C, IQR 0.4-1.3 \({}^{\circ}\)C; \(p_{adj}\) = 0.19) or Group 4 (median 0.7 \({}^{\circ}\)C, IQR 0.3-0.8 \({}^{\circ}\)C; \(p_{adj}\) = 0.19).  
At Tc3, the average temperature increment showed a median of 1.0 \({}^{\circ}\)C (IQR 0.7-1.1 \({}^{\circ}\)C) in Group 1, which was higher with respect to Group 2 (median 0.4 \({}^{\circ}\)C, IQR 0.1-0.7 \({}^{\circ}\)C; \(p_{adj}\) = 0.03), Group 3 (median 0.6 \({}^{\circ}\)C, IQR 0.1-0.7 \({}^{\circ}\)C; \(p_{adj}\) = 0.03) and Group 4 (median 0.3 \({}^{\circ}\)C, IQR 0.2-0.7 \({}^{\circ}\)C; \(p_{adj}\) = 0.03).  
Figure 5: Boxplot showing the largest temperature variation (\(\Delta\)T) at Tc1 in the four groups.  
Figure 6: Boxplots showing the largest of temperature variation (\(\Delta\)T) at Tc2 (**a**) and Tc3 (**b**) in the four groups.  
Post-experimental CBCT observations revealed the presence of radio-opaque material partially occluding the aperture of the internal irrigation tubes and also attached to the inner surface of the guide sleeves (Figure 8).