Effect of Cutting and Rescanning Methods on Trueness and Mesh Density of Digital Intraoral Scans.

Purpose: To evaluate the effects of different cutting and rescanning methods on the trueness of digital impressions and mesh density. In particular, the contribution of the high definition (HD) rescanning mode to scanning results was analyzed.

Materials and methods: The fully dentate model with a prepared mandibular right first molar was scanned using a reference scanner. The main model was repeatedly scanned with Trios 3 (T) and Medit i700 (M; T0, M0). Two copies of each scan were obtained. The crown region of the mandibular right first molar was cut and rescanned in standard resolution (T1, M1) and high resolution (T2, M2). The digital data were analyzed using CloudCompare and Meshlab software. Trueness was assessed based on RMS values obtained from 3D comparisons with the reference model.

Results: While no significant differences were observed in the RMS values of full-arch scans, significant differences were found in crown RMS values (P < .001). T0 (29.03 μm) exhibited lower deviation compared to M0 (33.89 μm). M2 (29.29 μm) showed a significantly lower RMS value than M0 (33.89 μm). No significant differences were found between T0 (29.03 μm), T1 (29.28 μm), and T2 (27.22 μm). Significantly higher mesh density was detected in the M1 and M2 groups compared to the others (M1 = 42,170, M2 = 42,956).

Conclusions: Rescanning methods may affect scanning accuracy and mesh density. Specifically, the high-resolution mode of the Medit i700 has the potential to provide better accuracy and detail in localized areas.