(PO62) Working Length Determination of Mandibular First Molars Using CBCT Versus a New Digital Ruler (Digit R, B&L Biotech) as a Gold Standard

Abstract: Instrumentation to the proper apical limit is essential for endodontic success. With the advent of cone beam computed tomography (CBCT), clinicians can now appreciate detailed root canal morphology and adjust their instrumentation protocol to better treat pulpal and periapical disease. However, there is not a strong consensus in the literature regarding the use of CBCT for working length measurements versus a gold standard. This study aimed to compare CBCT working length measurements of mandibular first molars against a gold standard using a new digital ruler. Twenty-one extracted mandibular first molars were scanned and evaluated using CBCT (3D Accuitomo 170) and i-Dixel 3D imaging software. Working lengths of mesio-buccal canals were determined based on the average of three measurements from the axial slice. Teeth were accessed and instrumented until a size 15 K-file was visualized at the apical foramen. Working lengths of files were determined using a new digital ruler (Digit R, B&L Biotech). Measurements from CBCT scans and the digital ruler were submitted for statistical analysis. A total of 42 measurements were analyzed using CBCT imaging and the Digit R. Two measurement samples were determined as outliers and excluded from analysis. The mean working length for CBCT was 18.23 mm (SD = 1.62). The mean working length for Digit R was 18.58 mm (SD = 1.66). No significant difference was noted between measurement modalities based on measured working lengths, p = .51. CBCT technology may be a helpful and accurate tool for determining working length prior to endodontic therapy.