dimensional cone
Recently Published Documents


TOTAL DOCUMENTS

239
(FIVE YEARS 46)

H-INDEX

30
(FIVE YEARS 4)

2022 ◽  
Author(s):  
Anshuman Pandey ◽  
Katya M. Casper ◽  
Daniel R. Guildenbecher ◽  
Steven J. Beresh ◽  
Rajkumar Bhakta ◽  
...  

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Yangdong Lin ◽  
Miao He

In order to deeply study oral three-dimensional cone beam computed tomography (CBCT), the diagnosis of oral and facial surgical diseases based on deep learning was studied. The utility model related to a deep learning-based classification algorithm for oral neck and facial surgery diseases (deep diagnosis of oral and maxillofacial diseases, referred to as DDOM) is brought out; in this method, the DDOM algorithm proposed for patient classification, lesion segmentation, and tooth segmentation, respectively, can effectively process the three-dimensional oral CBCT data of patients and carry out patient-level classification. The segmentation results show that the proposed segmentation method can effectively segment the independent teeth in CBCT images, and the vertical magnification error of tooth CBCT images is clear. The average magnification rate was 7.4%. By correcting the equation of R value and CBCT image vertical magnification rate, the magnification error of tooth image length could be reduced from 7.4. According to the CBCT image length of teeth, the distance R from tooth center to FOV center, and the vertical magnification of CBCT image, the data closer to the real tooth size can be obtained, in which the magnification error is reduced to 1.0%. Therefore, it is proved that the 3D oral cone beam electronic computer based on deep learning can effectively assist doctors in three aspects: patient diagnosis, lesion localization, and surgical planning.


2021 ◽  
Vol 149 (11) ◽  
pp. 4569-4581
Author(s):  
Tomohiro Okuma ◽  
Kei-ichi Watanabe ◽  
Ken-ichi Yoshida

2021 ◽  
Vol 5 (1) ◽  
pp. 34-35
Author(s):  
Waria O. Amin

The sand clock is a device used to measure time, consisting of two conical glass bulbs, which are connected vertically by a small opening neck. The top contains grains of fine dry sand. The upper part symbolizes the future,   sand passes through the neck (which indicates present) to the lower part which turned past. In 1907, German scientist Hermann Minkowski (1864-1909) interpreted the concept of the four-dimensional space-time of Einstein's theory in a two-dimensional cone diagram, in which the upper cone symbolizes the future, the neck the present and the lower part the past.  The researcher has noticed a great likeness, to the point of congruence between the shape and function of both, the sand clock and the diagram. This resemblance aroused speculations that Hermann Minkowski had been inspired by the sand hour in drawing his diagram. It cannot be attributed to a merely chance.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kyungjae Han ◽  
Mun Cheol Kim ◽  
Youn Joong Kim ◽  
Yunheon Song ◽  
Ilho Tae ◽  
...  

AbstractThe aim of this study was to assess the changes in individual condyles from 5 to 8 years in patients with temporomandibular joint (TMJ) osteoarthritis using 3-dimensional cone beam computed tomography (3D CBCT) reconstruction and superimposition. To assess the longitudinal TMJ changes, CBCT was performed at initial (T0) and final (T2) timepoints that were at least 5 years apart and at a middle (T1) timepoint. To improve the accuracy, we used a novel superimposition method that designated areas of coronoid process and mandibular body. The differences in the resorption and apposition amounts were calculated between each model via maximum surface distances. The greatest resorption and apposition observed were − 7.48 and 2.66 mm, respectively. Evaluation of the changes in each condyle showed that osteoarthritis leads to both resorption and apposition. Resorption was mainly observed in the superior region, while high apposition rates were observed (in decreasing order) in the posterior, lateral, and anterior regions. The medial parts showed greater apposition than the lateral parts in all regions. Our superimposition method reveals that both resorption and apposition were observed in condyles with TMJ osteoarthritis, and resorption/apposition patterns depend on the individual condyle and its sites.


Author(s):  
A. A. Hovhannisyan

The fermionic condensate is investigated for a field localized on a finite radius 2- dimensional cone in the presence of a magnetic flux threading the cone apex. On the edge of the cone a boundary condition is imposed that differs from the MIT bag boundary condition, most frequently used for the confinement of fermions. The fermionic condensate is decomposed into the boundary-free and edge-induced contributions. Both these parts are periodic functions of the magnetic flux with the period equal to the flux quantum.


2021 ◽  
Author(s):  
Brian Wilson ◽  
Nikoleta Konstantoni ◽  
Ki Beom Kim ◽  
Patrick Foley ◽  
Hiroshi Ueno

ABSTRACT Objectives To compare treatment effects of the standard and shorty Class II Carriere Motion appliances (CMAs) on adolescent patients. Materials and Methods Fifty adolescents with Class II malocclusion formed group 1, who were treated with shorty CMA (n = 25, 12.66 ± 1.05 years), and age- and sex–matched group 2, who were treated with standard CMA (n = 25, 12.73 ± 1.07 years). Treatment effects were analyzed by tracing with Invivo software to compare pretreatment (T1) cone-beam computed tomography (CBCT) images with post-CMA (T2) CBCT images. A total of 23 measurements were compared within and between groups. Results In groups 1 and 2, maxillary first molars showed significant distal movement from T1 to T2 (1.83 ± 2.11 mm and 2.14 ± 1.34 mm, respectively), with distal tipping and rotation in group 1 (6.52° ± 3.99° and 3.15° ± 7.52°, respectively) but only distal tipping (7.03° ± 3.45°) in group 2. Similarly, in both groups, the maxillary first premolars experienced significant distal movement with distal tipping but no significant rotation. In group 1, maxillary canines did not undergo significant distal movement. In both groups 1 and 2, mandibular first molars experienced significant mesial movement (1.85 ± 1.88 mm and 2.44 ± 2.02 mm, respectively). Group 1 showed statistically significantly less reduction in overjet and less canine distal movement with less distal tipping than group 2 (α < .05). Conclusions The shorty CMA achieved Class II correction similarly to the standard CMA, with less change in overjet and distal tipping movement of the maxillary canines.


Sign in / Sign up

Export Citation Format

Share Document