Accuracy Assessment of Three-dimensional Surface Reconstructions of In vivo Teeth from Cone-beam Computed Tomography

Abstract

Background:The accuracy of three-dimensional (3D) reconstructions from cone-beam computed tomography (CBCT) has been particularly important in dentistry, which will affect the effectiveness of diagnosis, treatment plan, and outcome in clinical practice. The aims of this study were to assess the linear, volumetric, and geometric accuracy of 3D reconstructions from CBCT and to investigate the influence of voxel size and CBCT system on the reconstructions results.Methods:Fifty teeth from 18 orthodontic patients were assigned to three groups as NewTom VG 0.15 mm group (NewTom VG; voxel size: 0.15 mm; n = 17), NewTom VG 0.30 mm group (NewTom VG; voxel size: 0.30 mm; n = 16), and VATECH DCTPRO 0.30 mm group (VATECH DCTPRO; voxel size: 0.30 mm; n = 17). The 3D reconstruction models of the teeth were segmented from CBCT data manually using Mimics 18.0 (Materialise Dental, Leuven, Belgium), and the extracted teeth were scanned by 3Shape optical scanner (3Shape A/S, Denmark). Linear and volumetric deviations were separately assessed by comparing the length and volume of the 3D reconstruction model with physical measurement by paired t-test. Geometric deviations were assessed by the root mean square value of the imposed 3D reconstruction and optical models by one-sample t-test. To assess the influence of voxel size and CBCT system on 3D reconstruction, analysis of variance (ANOVA) was used (α = 0.05).Results:The linear, volumetric, and geometric deviations were −0.03 ± 0.48 mm, −5.4 ± 2.8%, and 0.117 ± 0.018 mm for NewTom VG 0.15 mm group; −0.45 ± 0.42 mm, −4.5 ± 3.4%, and 0.116 ± 0.014 mm for NewTom VG 0.30 mm group; and −0.93 ± 0.40 mm, −4.8 ± 5.1%, and 0.194 ± 0.117 mm for VATECH DCTPRO 0.30 mm group, respectively. There were statistically significant differences between groups in terms of linear measurement (P < 0.001), but no significant difference in terms of volumetric measurement (P = 0.774). No statistically significant difference were found on geometric measurement between NewTom VG 0.15 mm and NewTom VG 0.30 mm groups (P = 0.999) while a significant difference was found between VATECH DCTPRO 0.30 mm and NewTom VG 0.30 mm groups (P = 0.006).Conclusions:The 3D reconstruction from CBCT data can achieve a high linear, volumetric, and geometric accuracy. Increasing voxel resolution from 0.30 to 0.15 mm does not result in increased accuracy of 3D tooth reconstruction while different systems can affect the accuracy.

In vivo accuracy of tooth surface reconstruction based on CBCT and dental MRI—A clinical pilot study

“…Furthermore, a new method for reliable and accurate 3D tooth surface reconstruction based on dMRI was established. Geometric deviations for dMRI remained within the predefined equivalence margin of ±0.2 mm, which was based on previously published in vivo results for CBCT (Sang et al, ). The accuracy of dMRI, however, was still substantially lower than that of CBCT.…”

“…These results are comparable with those of Al‐Rawi et al () who reported mean RMS ± SD errors between CBCT and µCT of 0.139 ± 0.0411 mm (0.133 mm isotropic voxel size), 0.191 ± 0.044 (0.2 mm isotropic voxel size), and 0.21 ± 0.059 mm (0.25 mm isotropic voxel size) for two dry, metal‐free human mandibles. So far, only one publication has studied geometric accuracy in vivo among 18 young orthodontic patients and compared the results from CBCT with those from an optical scanner (Sang et al, ). For two different voxel sizes (0.15 and 0.3 mm isotropic) and two different CBCT machines, the authors reported a mean RMS ± SD range of 0.117 ± 0.018 mm to 0.194 ± 0.117 mm.…”

Computer-aided three-dimensional assessment of periodontal healing distal to the mandibular second molar after coronectomy of the mandibular third molar: a prospective study

“…CBCT data in Digital Imaging and Communications in Medicine format at baseline and Po.6 m were imported into Mimics™ 19.0 (Materialise Dental, Leuven, Belgium). Digital models of mandibular bone, extraction socket (a digital model of hard tissue containing the entire extraction socket), the M2M, and root complex of the M3M after coronectomy were segmented and saved in stereolithography le format for further analyses in GeoMagic™ Studio 12 (3D Systems, Rock Hill, SC, USA) [19]. Models of mandible bone with clear anatomic markers were applied for registration according to the "Best-Fit Alignment" algorithm [25,26].…”

“…The geometric deviation of the M2M at different times was calculated according to the "Deviation" algorithm. Mean ± SD values were recorded and the distribution of distance shown on a graphical color map [19] (Fig. 1A-C).…”

“…Recently, the combination of 3D cone-beam computed tomography (CBCT) data and digital software enabled the reconstruction and registration of digital models of tooth or bone. It provided excellent reproducibility and accuracy to comparative analysis [18,19]. Guidance of implant surgery [20] and navigation of oral and maxillofacial surgery [21] can employ this new method.…”