Tibia vara in Asians: Myth or fact? Verification with three-dimensional computed tomography

Background: There is a common perception among surgeons that Asian tibiae are significantly more varus compared to non-Asians, contributed both by an acute medial tibial proximal angle (MPTA) and diaphyseal bowing. Insight into the normative morphology of the tibia allows generation of knowledge towards disease processes and subsequently planning for corrective surgeries. Methods: Computed tomography (CT) scans of 100 normal adult knees, aged 18 years and above, were analysed using a 3-dimensional (3D) analysis software. All tibiae were first aligned to a standard frame of reference and then rotationally aligned to the tibial centroid axis (TCAx) and the transmalleolar axis (tmAx). MPTA was measured from best-fit planes on the surface of the proximal tibia for each rotational alignment. Diaphyseal bowing was assessed by dividing the shaft to three equal portions and establishing the angle between the proximal and distal segments. Results: The mean MPTA was 87.0° ± 2.2° (mean ± SD) when rotationally aligned to TCAx and 91.6° ± 2.7° when aligned to tmAx. The mean diaphyseal bowing was 0.1° ± 1.9° varus when rotationally aligned to TCAx and 0.3° ± 1.6° valgus when aligned to tmAx. The mean difference when the MPTA was measured with two different rotational alignments (TCAx and tmAx) was 4.6° ± 2.3°. No statistically significant differences were observed between males and females. Post hoc tests revealed statistically significant difference in MPTA between different ethnic sub-groups. Conclusion: The morphology of the proximal tibiae in the disease-free Asian knee is inherently varus but not more so than other reported populations. The varus profile is contributed by the MPTA, with negligible diaphyseal bowing. These implications are relevant to surgical planning and prosthesis design.

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Three-dimensional assessment of the anterior and inferior loop of the inferior alveolar nerve using computed tomography images in patients with and without mandibular asymmetry

BMC Oral Health ◽

10.1186/s12903-021-01424-3 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Jae-Young Kim ◽

Michael D. Han ◽

Kug Jin Jeon ◽

Jong-Ki Huh ◽

Kwang-Ho Park

Keyword(s):

Computed Tomography ◽

Symmetry Group ◽

Three Dimensional ◽

Inferior Alveolar Nerve ◽

Mental Foramen ◽

3D Analysis ◽

Mandibular Asymmetry ◽

Computed Tomography Images ◽

Significant Difference ◽

Mandibular Body

Abstract Background The purpose of this study was to investigate the differences in configuration and dimensions of the anterior loop of the inferior alveolar nerve (ALIAN) in patients with and without mandibular asymmetry. Method Preoperative computed tomography images of patients who had undergone orthognathic surgery from January 2016 to December 2018 at a single institution were analyzed. Subjects were classified into two groups as “Asymmetry group” and “Symmetry group”. The distance from the most anterior and most inferior points of the ALIAN (IANant and IANinf) to the vertical and horizontal reference planes were measured (dAnt and dInf). The distance from IANant and IANinf to the mental foramen were also calculated (dAnt_MF and dInf_MF). The length of the mandibular body and symphysis area were measured. All measurements were analyzed using 3D analysis software. Results There were 57 total eligible subjects. In the Asymmetry group, dAnt and dAnt_MF on the non-deviated side were significantly longer than the deviated side (p < 0.001). dInf_MF on the non-deviated side was also significantly longer than the deviated side (p = 0.001). Mandibular body length was significantly longer on the non-deviated side (p < 0.001). There was no significant difference in length in the symphysis area (p = 0.623). In the Symmetry group, there was no difference between the left and right sides for all variables. Conclusion In asymmetric patients, there is a difference tendency in the ALIAN between the deviated and non-deviated sides. In patients with mandibular asymmetry, this should be considered during surgery in the anterior mandible.

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Aesthetic evaluation of the labiolingual position of maxillary lateral incisors by orthodontists and laypersons

10.21203/rs.3.rs-25551/v2 ◽

2020 ◽

Author(s):

Xue Jiang ◽

Zhiwei Cao ◽

Yang Yao ◽

Zhihe Zhao ◽

Wen Liao

Keyword(s):

Three Dimensional ◽

Aesthetic Perception ◽

Aesthetic Evaluation ◽

Anterior Teeth ◽

Significant Difference ◽

Dental Model ◽

Males And Females ◽

The Aesthetic ◽

Post Hoc ◽

Smile Aesthetics

Abstract Background: The maxillary anterior teeth play a crucial role in smile aesthetics. Previous studies regarding the importance of maxillary lateral incisors for smile aesthetics concentrated on their size, incisor edge level, and inclination, etc. However, the aesthetic effect of lateral incisor movement in the spatial position has not been studied yet. Therefore, the purpose of this study was to explore the influence of the labiolingual position of maxillary lateral incisors on the aesthetic perception of smiles by orthodontists and laypersons, as well as analyze differences in this perception between male and female raters.Methods: A three-dimensional (3D) dental model was generated from the photograph of a man’s smile using iOrtho7.0 software (Time Angel, Wuxi, China). Based on this model, seven images were generated with different labiolingual positions of the maxillary lateral incisors in 0.5 mm increments (+ indicating labial translation, and - indicating lingual translation). The images were evaluated by 86 orthodontists and 161 laypersons using a visual analog scale, with lower scores indicating less attractiveness. Data were analyzed using Student’s t test and one-way analysis of variance with post hoc test.Results: There was no significant difference in smile ratings by males and females. Orthodontists assigned lower scores to all images than laypersons. The smile at +1.5 mm was considered the least attractive by orthodontists, while smiles at +1.5 mm and -1.5 mm were regarded as the least attractive by laypersons. The smile at 0 mm was evaluated as the most attractive by all raters. Laypersons gave different scores to smiles at 0 or -0.5 mm, but orthodontists did not.Conclusions: The labiolingual position of maxillary lateral incisors does affect the perception of smile aesthetics. Orthodontists may rate smile aesthetics more critically than laypersons. Therefore, communication and discussion between orthodontists and patients is needed to achieve better therapeutic and aesthetic outcomes.

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Comparing the Use of 3D Photogrammetry and Computed Tomography in Assessing the Severity of Single-Suture Nonsyndromic Craniosynostosis

Plastic Surgery ◽

10.1177/2292550317694845 ◽

2017 ◽

Vol 25 (2) ◽

pp. 78-83 ◽

Cited By ~ 4

Author(s):

Olivia A. Ho ◽

Nikoo Saber ◽

Derek Stephens ◽

April Clausen ◽

James Drake ◽

...

Keyword(s):

Computed Tomography ◽

Soft Tissue ◽

Confidence Interval ◽

Three Dimensional ◽

Computed Tomography Images ◽

Younger Age ◽

Significant Difference ◽

3D Photogrammetry ◽

The Mean ◽

Single Suture

Purpose: Single-suture nonsyndromic craniosynostosis is diagnosed using clinical assessment and computed tomography (CT). With increasing awareness of the associated risks of radiation exposure, the use of CT is particularly concerning in patients with craniosynostosis since they are exposed at a younger age and more frequently than the average child. Three-dimensional (3D) photogrammetry is advantageous—it involves no radiation, is conveniently obtainable within clinic, and does not require general anaesthesia. This study aims to assess how 3D photogrammetry compares to CT in the assessment of craniosynostosis severity, to quantify surgical outcomes, and analyze the validity of 3D photogrammetry in craniosynostosis. Methods: Computed tomography images and 3D photographs of patients who underwent craniosynostosis surgery were assessed and aligned to best fit. The intervening area between the CT and 3D photogrammetry curves at the supraorbital bar (bandeau) level in axial view was calculated. Statistical analysis was performed using Student t test. Ninety-five percent confidence intervals were determined and equivalence margins were applied. Results: In total, 41 pairs of CTs and 3D photographs were analyzed. The 95% confidence interval was 198.16 to 264.18 mm2 and the mean was 231.17 mm2. When comparisons were made in the same bandeau region omitting the temporalis muscle, the 95% confidence interval was 108.94 to 147.38 mm2, and the mean was 128.16 mm2. Although statistically significant difference between the modalities was found, they can be attributable to the dampening effect of soft tissue. Conclusion: Within certain error margins, 3D photogrammetry is comparable to CT in assessing the severity of single-suture nonsyndromic craniosynostosis. However, a dampening effect can be attributable to the soft tissue. Three-dimensional photogrammetry may be more applicable for severe cases of craniosynostosis but not milder deformity. It may also be beneficial for assessing the overall appearance and aesthetics but not for determining underlying bony severity.

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Facial Flatness Indices: A Comparison of Two Methods of Assessment

Journal of Clinical Imaging Science ◽

10.25259/jcis_66_2020 ◽

2020 ◽

Vol 10 ◽

pp. 68

Author(s):

Chimène Chalala ◽

Maria Saadeh ◽

Fouad Ayoub

Keyword(s):

Computed Tomography ◽

Cone Beam Computed Tomography ◽

Three Dimensional ◽

Cone Beam ◽

Class Iii ◽

Direct Measurements ◽

Significant Difference ◽

Males And Females ◽

Trigonometric Formula

Objectives: The objective of the study was to evaluate and compare facial flatness indices calculated from the trigonometric formula as opposed to those generated from the direct measurements on three-dimensional radiographs. Material and Methods: A total of 322 cone-beam computed tomography radiographs were digitized and three facial indices (frontal, simotic, and zygomaxillary) were assessed in two different methods and compared between different groups. Results: There was a discrepancy between facial flatness indices generated from the two different approaches. The highest difference was seen in the findings of the simotic index and the lowest for the zygomaxillary index. No statistically significant difference was displayed in the three formula-generated flatness indices between males and females and between growing and non-growing subjects (P > 0.05). The zygomaxillary index was the only measurement revealing no statistically significant difference in Class III sagittal malocclusions (t = −0.5 P = 0.621). The orthodontic application would yield to the same interpretations for both ways of indices calculation. Conclusion: The validity of the trigonometric formula used to appraise facial flatness indices might be questionable. The zygomaxillary index could be more clinically considered compared to the frontal and simotic indices.

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Aesthetic evaluation of the labiolingual position of maxillary lateral incisors by orthodontists and laypersons

10.21203/rs.3.rs-25551/v3 ◽

2021 ◽

Author(s):

Xue Jiang ◽

Zhiwei Cao ◽

Yang Yao ◽

Zhihe Zhao ◽

Wen Liao

Keyword(s):

Three Dimensional ◽

Aesthetic Perception ◽

Aesthetic Evaluation ◽

Anterior Teeth ◽

Significant Difference ◽

Dental Model ◽

Males And Females ◽

The Aesthetic ◽

Post Hoc ◽

Smile Aesthetics

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Reproducibility of landmark identification in the jaw and teeth on 3-dimensional cone-beam computed tomography images

The Angle Orthodontist ◽

10.2319/010711-5.1 ◽

2011 ◽

Vol 81 (5) ◽

pp. 843-849 ◽

Cited By ~ 22

Author(s):

Mariko Fuyamada ◽

Hiroyuki Nawa ◽

Momoko Shibata ◽

Kazuhito Yoshida ◽

Yoshitaka Kise ◽

...

Keyword(s):

Computed Tomography ◽

Cone Beam Computed Tomography ◽

Three Dimensional ◽

Cone Beam ◽

Volume Data ◽

3D Images ◽

3 Dimensional ◽

Computed Tomography Images ◽

Landmark Identification ◽

Significant Difference

Abstract Objective: To compare the reproducibility of landmark identification on three-dimensional (3D) cone-beam computed tomography (CBCT) images between procedures based on traditional cephalometric definitions (procedure 1) and those tentatively proposed for 3D images (procedure 2). Materials and Methods: A phantom with embedded dried human skull was scanned using CBCT. The acquired volume data were transferred to a personal computer, and 3D images were reconstructed. Eighteen dentists plotted nine landmarks related to the jaws and teeth four times: menton (Me), pogonion (Po), upper-1 (U1), lower-1 (L1), left upper-6 (U6), left lower-6 (L6), gonion (Go), condyle (Cd), and coronoid process (Cp). The plotting reliabilities of the two procedures were compared by calculating standard deviations (SDs) in three components (x, y, and z) of coordinates and volumes of 95% confidence ellipsoid. Results: All 27 SDs for procedure 2 were less than 1 mm, and only five of them exceeded 0.5 mm. The variations were significantly different between the two procedures, and the SDs of procedure 2 were smaller than those of procedure 1 in 21 components of coordinates. The ellipsoid volumes were also smaller for procedure 2 than procedure 1, although a significant difference was not found. Conclusions: Definitions determined strictly on each three sectional images, such as for procedure 2, were required for sufficient reliability in identifying the landmark related to the jaws and teeth.

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Aesthetic evaluation of the labiolingual position of maxillary lateral incisors by orthodontists and laypersons

BMC Oral Health ◽

10.1186/s12903-021-01402-9 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Xue Jiang ◽

Zhiwei Cao ◽

Yang Yao ◽

Zhihe Zhao ◽

Wen Liao

Keyword(s):

Three Dimensional ◽

Aesthetic Perception ◽

Aesthetic Evaluation ◽

Anterior Teeth ◽

Significant Difference ◽

Dental Model ◽

Males And Females ◽

The Aesthetic ◽

Post Hoc ◽

Smile Aesthetics

Abstract Background The maxillary anterior teeth play a crucial role in smile aesthetics. Previous studies regarding the importance of maxillary lateral incisors for smile aesthetics concentrated on their size, incisor edge level, and inclination, etc. However, the aesthetic effect of lateral incisor movement in the spatial position has not been studied yet. Therefore, the purpose of this study was to explore the influence of the labiolingual position of maxillary lateral incisors on the aesthetic perception of smiles by orthodontists and laypersons, as well as analyze differences in this perception between male and female raters. Methods A three-dimensional (3D) dental model was generated from the photograph of a man’s smile using iOrtho7.0 software (Time Angel, Wuxi, China). Based on this model, seven images were generated with different labiolingual positions of the maxillary lateral incisors in 0.5 mm increments (+ indicating labial translation, and—indicating lingual translation). The images were evaluated by 86 orthodontists and 161 laypersons using a visual analog scale, with lower scores indicating less attractiveness. Data were analyzed using Student’s t test and one-way analysis of variance with post hoc test. Results There was no significant difference in smile ratings by males and females. Orthodontists assigned lower scores to all images than laypersons. The smile at + 1.5 mm was considered the least attractive by orthodontists, while smiles at + 1.5 mm and − 1.5 mm were regarded as the least attractive by laypersons. The smile at 0 mm was evaluated as the most attractive by all raters. Laypersons gave different scores to smiles at 0 or − 0.5 mm, but orthodontists did not. Conclusions The labiolingual position of maxillary lateral incisors does affect the perception of smile aesthetics. Orthodontists may rate smile aesthetics more critically than laypersons. Therefore, communication and discussion between orthodontists and patients is needed to achieve better therapeutic and aesthetic outcomes.

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Dimensional Accuracy of Dental Models for Three-Unit Prostheses Fabricated by Various 3D Printing Technologies

Materials ◽

10.3390/ma14061550 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1550

Author(s):

Soo-Yeon Yoo ◽

Seong-Kyun Kim ◽

Seong-Joo Heo ◽

Jai-Young Koak ◽

Joung-Gyu Kim

Keyword(s):

Surface Roughness ◽

Three Dimensional ◽

Dimensional Accuracy ◽

3D Analysis ◽

Digital Light Processing ◽

Test Models ◽

Reference File ◽

Significant Difference ◽

Jet Printing ◽

3D Printed

Previous studies on accuracy of three-dimensional (3D) printed model focused on full arch measurements at few points. The aim of this study was to examine the dimensional accuracy of 3D-printed models which were teeth-prepped for three-unit fixed prostheses, especially at margin and proximal contact areas. The prepped dental model was scanned with a desktop scanner. Using this reference file, test models were fabricated by digital light processing (DLP), Multi-Jet printing (MJP), and stereo-lithography apparatus (SLA) techniques. We calculated the accuracy (trueness and precision) of 3D-printed models on 3D planes, and deviations of each measured points at buccolingual and mesiodistal planes. We also analyzed the surface roughness of resin printed models. For overall 3D analysis, MJP showed significantly higher accuracy (trueness) than DLP and SLA techniques; however, there was not any statistically significant difference on precision. For deviations on margins of molar tooth and distance to proximal contact, MJP showed significantly accurate results; however, for a premolar tooth, there was no significant difference between the groups. 3D color maps of printed models showed contraction buccolingually, and surface roughness of the models fabricated by MJP technique was observed as the lowest. The accuracy of the 3D-printed resin models by DLP, MJP, and SLA techniques showed a clinically acceptable range to use as a working model for manufacturing dental prostheses

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Jones Fractures Identified at the National Football League Scouting Combine: Assessment of Prognostic Factors, Computed Tomography Findings, and Initial Career Performance

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967118790740 ◽

2018 ◽

Vol 6 (8) ◽

pp. 232596711879074 ◽

Cited By ~ 4

Author(s):

Robert C. Spang ◽

Daniel B. Haber ◽

Brendin R. Beaulieu-Jones ◽

Kristen L. Stupay ◽

George Sanchez ◽

...

Keyword(s):

Computed Tomography ◽

National Football League ◽

Treatment Method ◽

Level Of Evidence ◽

Significant Difference ◽

Specific Performance ◽

Incomplete Healing ◽

Bony Healing ◽

The Mean ◽

Career Performance

Background: Jones fractures result in subsequent dysfunction and remain an issue for athletes. Purpose: To (1) describe the epidemiology, treatment, and impact of Jones fractures identified at the National Football League (NFL) Scouting Combine on players’ early careers and (2) establish the value of computed tomography (CT) to determine bony healing after a fracture in prospective players. Study Design: Cohort study; Level of evidence, 3. Methods: All players who attended the combine between 2009 and 2015 were retrospectively reviewed to identify their history of Jones fractures. The playing position, treatment method, and number of missed collegiate games were recorded. The mean overall draft pick number, number of games started and played, snap percentage, and position-specific performance scores (fantasy score) over the first 2 years in the NFL were compared between players with fractures and controls. An imaging classification system was applied based on grading of each quadrant of the fifth metatarsal (plantar, dorsal, medial, lateral), with a score of 0 for not healed or 1 for healed. Results: Overall, the number of Jones fractures identified was 72 in 2285 athletes (3.2%), with all treated via intramedullary screw fixation. The mean overall draft pick number for players with fractures was 111.2 ± 67.9 compared with 99.0 ± 65.9 for controls ( P = .12). Performance scores for players with fractures were lower than those for controls across all positions, with a significant difference in running backs (2.6 vs 4.0, respectively; P < .001) and defensive linemen (1.4 vs 2.3, respectively; P = .02). The mean CT score was 2.5 ± 1.3. Of the 32 athletes who underwent imaging, 16 Jones fractures (50.0%) were healed or nearly healed, 12 (37.5%) were partially healed, and 4 (12.5%) showed little or no healing. The plantar cortex demonstrated the least healing (18/32; 56.3%), followed by the lateral cortex (15/32; 46.9%). Players with a mean score <1 were found to have fewer games started (2.7 ± 2.5) than those with 1 to 3 cortices healed (17.4 ± 10.4) or all cortices healed (8.7 ± 11.2). Conclusion: Based on CT, 50% of all players with a previous Jones fracture demonstrated incomplete healing. Moreover, position-specific performance scores over the first 2 years of a player’s career were lower across all positions for those with fractures compared with controls. Players with CT scores <1 were found to start fewer games and were drafted later than controls.

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Evaluating the Effect of Three-Dimensional Visualization on Force Application and Performance Time during Robotics-Assisted Mitral Valve Repair

Innovations Technology and Techniques in Cardiothoracic and Vascular Surgery ◽

10.1097/imi.0b013e3182a3200e ◽

2013 ◽

Vol 8 (3) ◽

pp. 199-205 ◽

Cited By ~ 2

Author(s):

Maria E. Currie ◽

Ana Luisa Trejos ◽

Reiza Rayman ◽

Michael W.A. Chu ◽

Rajni Patel ◽

...

Keyword(s):

Cardiac Surgery ◽

Mitral Valve ◽

Haptic Feedback ◽

3D Visualization ◽

Three Dimensional ◽

Test Bed ◽

Mitral Valve Annuloplasty ◽

Significant Difference ◽

The Mean ◽

Mean Time

Objective The purpose of this study was to determine the effect of three-dimensional (3D) binocular, stereoscopic, and two-dimensional (2D) monocular visualization on robotics-assisted mitral valve annuloplasty versus conventional techniques in an ex vivo animal model. In addition, we sought to determine whether these effects were consistent between novices and experts in robotics-assisted cardiac surgery. Methods A cardiac surgery test-bed was constructed to measure forces applied during mitral valve annuloplasty. Sutures were passed through the porcine mitral valve annulus by the participants with different levels of experience in robotics-assisted surgery and tied in place using both robotics-assisted and conventional surgery techniques. Results The mean time for both the experts and the novices using 3D visualization was significantly less than that required using 2D vision (P < 0.001). However, there was no significant difference in the maximum force applied by the novices to the mitral valve during suturing (P = 0.7) and suture tying (P = 0.6) using either 2D or 3D visualization. The mean time required and forces applied by both the experts and the novices were significantly less using the conventional surgical technique than when using the robotic system with either 2D or 3D vision (P < 0.001). Conclusions Despite high-quality binocular images, both the experts and the novices applied significantly more force to the cardiac tissue during 3D robotics-assisted mitral valve annuloplasty than during conventional open mitral valve annuloplasty. This finding suggests that 3D visualization does not fully compensate for the absence of haptic feedback in robotics-assisted cardiac surgery.

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