## 4 Discussion
This requirement is satisfied by clinical surgical guides supported by adjacent teeth [22; 24] as well as in open-flap drillings of a fully edentulous arch according to the All-on-4 protocol [30]. Nevertheless, the All-on-4 treatment concept can be implemented in a less traumatic manner, by guided flapless implant bed preparation [31]. A surgical template with internal cooling prepared for such an application should ensure sufficient distance between the guide and the targeted soft tissue to enable the evacuation of the coolant fluid. Another advantage of the internal coolant pipe is demonstrated by the picture of the surgical template's bottom taken right after the measurements (Supplementary Materials, Figure S1), which indicates that the irrigation fluid jet flushes away the bone chips extracted by the drill. In addition to surgical drilling, dental implant procedures often require bone splitting, which is also associated with heat dissipation. The study by [PERSON] et al. revealed that surgical guides with internal irrigation channels ensured the lowest peak temperatures during bone splitting performed with a piezo-driven bone saw [32]. The mean temperature elevations observed in this study remained below the bone damage threshold even in osteotomies performed using a classical guide. Individual peak temperature rises, however, exceeded the 10 \({}^{\circ}\)C limit at 0.8 mm from the margin of the osteotomy in almost half of the final drillings conducted in the presence of the classical guide. In contrast, while using the guide with internal cooling, the critical limit was crossed in 17.9% of the final drillings. Hence, the internally routed irrigation reduced the probability of overheating 2.7-fold. This study demonstrates the superiority of surgical guides with internal coolant pipes compared to classical surgical guides. Its conclusions are strengthened by the standardized drilling parameters (thrust force, torque, and coolant flow), and the relatively large sample size (\(n=56\) data points per condition). Nevertheless, caution needs to be exercised when trying to translate the results of this study to the clinical setting. The use of standardized, artificial bone models ensured better reliability, but it is also an important limitation. The temperature rises observed here differ from actual bone temperature elevations expected in a clinical setting. To evaluate the corresponding changes in bone temperature, comparative thermodynamic investigations will be needed, along the lines devised by [PERSON] et al. [33], and in vivo measurements conducted on animal models. Further limitations of this study include the use of a single set of drills for all the osteotomies and the use of a single thermocouple per drilling site for temperature recordings. Drill wear is known to favor bone heating [7]. To mitigate its impact on our comparative study, we randomized the order of drillings performed with the two types of surgical guides. Nevertheless, drill wear most likely contributed to the wide distributions of the observed temperature changes. Temperature measurements conducted in a single point, subject to errors associated with thermocouple placement, provided a poor mapping of the temperature field created in the course of surgical drilling. Computer simulations revealed that most thermal damage is expected to occur within 0.5 mm of the edge of the osteotomy, which is precisely the region that drives osseointegration [5]. Thermocoouples are large compared to the thickness of this region, and their placement precision is limited. Future studies might rely on infrared thermography to characterize temperature distributions around the osteotomy site. One option is to apply the method devised by [PERSON] et al. [34] to map the bone heating caused by drilling in the presence of surgical templates with different cylinder designs. In their study, infrared thermography demonstrated the advantage of cylinders endowed with windows over cylinders with small lateral orifices or solid cylinders.