# Bone Temperature Variation Using a 3D-Printed Surgical Guide with Internal Irrigation
## 2 Materials and Methods
### Surgical Protocol  
The following conditions were tested: guided osteotomy using the surgical guide with external irrigation and an additional internal irrigation with the use of built-in tubes (Group 1); guided osteotomy using the surgical guide with external irrigation only (Group 2); guided osteotomy using the surgical guide without irrigation (Group 3); osteotomy finalized without the use of a surgical guide, with external irrigation (Group 4).  
Four dental implant osteotomies--one for each group--were carried out in each of the 12 ribs, so that a total of 48 sites were included in this study (Figure 3). The position of the osteotomies in each rib was randomized using a computer-generated method.  
Before the initiation of the experiment, the specimens were immersed in room-temperature (19 \({}^{\circ}\)C) water for 12 h. Each rib was clamped to a bench vise, the fixation pin holes were made and the surgical guide was then secured to the substrate. Lateral holes for the thermocouples were prepared with a 1.8 mm calibrated drill and their tips were then inserted.  
Osteotomies were performed using a surgical motor (Implantmed, W&H, Burmoos, Austria) and a 20:1 reduction surgical contra angle handpiece (WS-75, W&H) at 1200 rpm according to a sequential drill preparation, as suggested by the manufacturer (Zimmer Biomet Dental). Regarding the irrigation modalities, a 0.9% saline solution at room temperature was used for irrigation using the pump of the surgical motor for groups 1, 2 and 4 with an emission flow of 90 ml/min. A Y-type irrigation tubing set was connected to the external and to the built-in tube system for internal irrigation in Group 1; irrigation tube was connected only to the external irrigation in Group 2 and Group 4; in Group 3 irrigation was disabled.  
Certain(r) Tapered Navigator(r) System For Guided Surgery (Zimmer Biomet Dental) was utilized. The following drill sequence was used with a continuous movement: Cortical Perforator drill, 2.0 mm, 2.75 mm, 3.00 mm, and 3.25 mm twist drills. After each drilling, the osteotomy site was irrigated with room temperature saline solution with a syringe to remove bone chips and debris. Thirty seconds were waited between the finalization of one drilling step and the initiation of the following one. To secure a precise osteotomy in Group 4, an initial cortical engraving (approximately 1.5 mm deep) was carried out with the use of the surgical guide. According to the manufacturer, drill positioning handles were used. To prevent the effect of drill wear, four new drill sets were used, so that each drill was used for 12 osteotomies only.  
The guides were removed after the completion of the experiment and subjected to a CBCT with the same parameters as above with the aim of qualitatively investigating the condition of the internal tube system.  
Figure 2: (**a**) Schematic drawing of the procedure. A 4.1 \(\times\) 13 mm dental implant osteotomy was planned. The bone temperature was recorded at 1.5 mm from the nominal implant surface at three osteotomy depths from the bone crest: 1.5 mm (Tc1), 7 mm (Tc2), and 12 mm (Tc3). (**b**) One of the 3D-printed guides fixed on its own experimental specimen, with three thermocouples (Tc) in place.