J0230102 Automatic Determination of Three-Dimensional Tooth Axis Using Cone-Beam CT

Sakamoto, Makoto; Hayashi-Sakai, Sachiko; Kobayashi, Koichi; Endo, Hideaki

doi:10.1299/jsmemecj.2015._j0230102-

Cited by 2 publications

(4 citation statements)

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“…This proves that the CRes was included in the area without accuracy, as the CRes was determined to be found by our algorithm and process as near the center of gravity. The reproducible point was determined without a relationship to the form, due to objectively estimating the axis of the first molar 14,23,24) . The CRes may be determined if the axis is estimated in molars with a moderate breakdown crown, such as in attrition and dental caries.…”

Section: Analysis Model and Resultsmentioning

confidence: 99%

Three-dimensional location and distribution of the center of resistance in the maxillary first molar applied to occlusal force

2023

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We aimed to investigate the center of resistance (CRes) of the maxillary first molar to set the occlusal force through finite element analysis. The inclination of the molar was measured, with loading to the root on the crown, and the position and direction of the load that minimized the inclination were investigated. The CRes was defined as the set of midpoints of the minimum distances between the two lines. Nine hundred and ninety CRes points were estimated from forty-five lines. The CRes was estimated as the point 1.22 mm (Z), −0.74 mm (X), and 0.23 mm (Y) from the origin in the apical, distal, and buccal side directions, respectively, with an ellipsoid area of 1.578 (Z) mm×0.097 (X) mm×0.100 (Y) mm. Further research is required to make effective use of the CRes identified in this study for clinical applications.

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Section: Analysis Model and Resultsmentioning

confidence: 99%

Three-dimensional location and distribution of the center of resistance in the maxillary first molar applied to occlusal force

2023

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“…In this study, we estimated threedimensional tooth axes using CBCT data taken from 20 dry skulls using LSR, and found that it was possible to estimate the objective tooth axis by using the whole of the tooth surface, even in teeth with small surface defects such as tooth attrition or dental abrasion. Previous reports about determining the three-dimensional tooth axis from CBCT data used PCA (Kim et al 2012;Sakamoto et al 2015;Zhang et al 2016). Therefore, we compared the three-dimensional tooth axes defined by LSR and PCA.…”

Section: Discussionmentioning

confidence: 99%

“…for the PCA (Sakamoto et al 2015) were calculated with statistical software (R and R Commander, R: version 3.4.1 and Rcmdr; version 2.4-0, The R Foundation for Statistical Computing; Vienna University of Technology, Vienna, Austria). The first principal component with the highest variance was set as the tooth axis.…”

Section: Comparison Between the Long Axes Of Molars Calculated By Pcamentioning

confidence: 99%

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Estimation of three-dimensional long axes of the maxillary and mandibular first molars with regression analysis

et al. 2019

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The purpose of this study was to determine the long axes of molars with multiple roots through ordinary least squares regression (LSR) and to compare them with the axes defined by principal component analysis (PCA). Three-dimensional radiological images of 20 dry skulls were obtained by cone-beam computed tomography (CBCT). Data from maxillary and mandibular first molars were extracted from the CBCT DICOM data with a three-dimensional image visualization system. The obtained data were reconstructed, converted to STL files, and three-dimensional coordinate values were extracted. The long axes were estimated by an algorithm to synchronize the LSR line with the horizontal axis which was translated to the vertical axis. The axes of the molars defined by LSR were compared with the axes of the molars defined by PCA. The coordinate point number of each molar was 5400-5800. The algorithm for determining the tooth axes in this study consisted of four stages containing three steps each. The distance between the two axes calculated by the two methods (LSR and PCA) on the horizontal plane through the origin was less than 10 −12 mm and the deviations between them were less than 0.003°. The long axes of the molars estimated by LSR agree almost exactly with the axes estimated by PCA, and the accuracy is sufficient for clinical usage; however, the distance between them would shorten with a more severe convergence condition of the α value at each stage of this LSR system.

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J0230102 Automatic Determination of Three-Dimensional Tooth Axis Using Cone-Beam CT

Cited by 2 publications

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Three-dimensional location and distribution of the center of resistance in the maxillary first molar applied to occlusal force

Three-dimensional location and distribution of the center of resistance in the maxillary first molar applied to occlusal force

Estimation of three-dimensional long axes of the maxillary and mandibular first molars with regression analysis

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