Background Guided endodontics have high accuracy and are successful techniques that had been gradually used in endodontics in recent years. However, the guided bur produces excessive heat during continuous rotation and friction with root canal walls. It is not clear whether the degree of temperature increase may lead to periodontal ligament and alveolar bone damage. Methods Forty single-rooted premolars were scanned using CBCT and intra-oral scanner, and 3D-printed guided plates were made with the pre-designed access. A custom-made guided bur was used to prepare the access cavities. The postoperative CBCT data and pre-designed pathways were matched to evaluate the deviation between planned and virtual path. Another 18 single-rooted premolars were accessed with the guided plates and bur, ET20 and ProTaper F3, respectively. The temperature changes on the root surfaces were inspected with a thermocouple thermometer. Results The average deviation on the tip and the base of the bur were 0.30 mm and 0.28 mm (mesial/distal), and 0.28 mm and 0.25 mm (buccal/lingual). The average angle deviation was 3.62°. The mean root surface temperature rise of the guided endodontics group was 3.07℃, which was lower than that of the ProTaper F3 group (8.90℃) (P P
