Comparative evaluation of the efficacy of the digital static guide versus the freehand approach in endodontic microsurgery: in vitro study

Endodontic microsurgery traditionally relies on the freehand approach. Recently, digital static guides have been introduced to improve surgical precision and safety. This study aimed to evaluate the effectiveness of digital static guidance in preserving the mental foramen compared to the conventional freehand technique. Additionally, it assessed differences in the osteotomy size and the procedural time. Forty-eight 3D-printed models with 3D-printed separate lower second premolars were subjected to optical scans and Cone Beam Computed Tomography (CBCT). These models were divided into three groups according to the location of the mental foramen: Group 1 (located below the apex of the second premolar) Group 2 (located between first and second premolars) Group 3 (located between second premolar and first molar). Each group was further subdivided into two subgroups utilizing surgical static guides and the freehand technique. Post-operative CBCT scans were compared with preoperative scans to measure the distance between the osteotomy and the mental foramen. Additionally, the osteotomy surface area and the duration of the procedures were compared between the two techniques. The paired sample test was used at (P ≤ 0.05). The guided technique demonstrated significantly greater distance from the osteotomy to the mental foramen in all three groups. The osteotomy surface area, the osteotomy length and width were significantly reduced in the guided groups compared to the freehand groups across all anatomical positions. Additionally, the procedural time was significantly shorter in the guided approach for all groups. The variable positions of the mental foramen in relation to the premolar root do not affect the overall benefits provided by the static surgical guide compared to the freehand technique for efficient endodontic microsurgical procedures; reducing the surgical time and the osteotomy size leaving a wider bone margin around the mental foramen.