New-designed 3D printed surgical guide promotes the accuracy of endodontic microsurgery: a study of 14 upper anterior teeth

Abstract

We aimed to design a novel three-dimensional (3D) printed surgical guide and evaluate its accuracy in assisting endodontic microsurgeries. A new 3D printed surgical guide was designed by computer-aided design and computer-aided manufacturing (CAD/CAM) technology and applied to 7 patients who underwent endodontic microsurgeries of upper anterior teeth from 2020.01 to 2020.12 as the experimental group. 7 patients who suffered from endodontic microsurgeries operated by the same surgeon without using the surgical guide from 2019.01 to 2019.12 were selected as the control group. Cone beam computed tomography (CBCT) was performed more than 12 months after operation, and the accuracy of apical resection was compared between the two groups. The accuracy of the microsurgery focused on the length and angle of the root apical resection. In the study, CBCT data and oral digital scanning data were used to reconstruct 3D models of periapical lesions with soft and hard tissue information, based on which we designed the new 3D printed surgical guides. The guides were successfully applied to the apectomy in endodontic microsurgeries. The deviation of the apical resection length of the experimental group (0.467 ± 0.146 mm) was better than that of the control group (1.743 ± 0.122 mm) (P < 0.0001), and the deviation of the apical resection angle of the experimental group (9.711 ± 3.593°) was significantly less than that of the control group (22.400 ± 3.362°) (P < 0.0001). The 3D-printed surgical guide could effectively guide endodontic microsurgery and improve its accuracy by fixing both the position and the angle of apectomy. The new type of surgical guide could accurately localize the root apex and guide the apical resection.

Figure 1

The design process and clinical application in endodontic microsurgery. (A) CBCT data of and the virtual bur data were merged in the designning software. (B) Establish the long axis of the target tooth and build the virtual bur-cutting trajectory. (C) Virtual model of 3D printed surgical guide. (D) Material object of 3D printed surgical guide. (E) The full-thickness mucoperiosteal flap was raised and the root apex and cyst wall were exposed. (F) The guide was aligned in position. (G) Root apex was extracted under the guidance of the 3D printed guide. (H) iRoot BP was backfilled into the cavity after bleeding control.

Figure 2

Two cases of endodontic microsurgery with 3D printed surgical guide. Case 1: Preoperative radiographic imaging (A,B), periapical radiograph after root canal treatment (C), periapical radiograph right after microsurgery (D) and radiographic imaging recalled after 12 months (E,F). Case 2: Preoperative radiographic imaging (G,H), periapical radiograph after root canal treatment (I), periapical radiograph right after microsurgery (J) and radiographic imaging recalled after 12 months (K,L).

Figure 3

Accuracy assessment of apical resection length and apical resection angle. (A) Apex resection length deviation (RL) = preoperative root length (ac)—postoperative root length (ab)—preset apical resection length (3 mm). (B) The Angle (RA) formed by line ab and line cd is the deviation angle between the experimental apical section and the standard apical section. (C) The length deviation of apical resection was significantly reduced when the guide was used (P < 0.001). (D) The accuracy of the apical resection angle of the experimental group was better than that of the control group. (P < 0.001). (Sn: control group, Sg: experimental group).