scholarly journals 3D Printing of Stereolithographic Models with Open Protocol

2020 ◽  
pp. 421-431
Author(s):  
Jorge Oviedo-Quirós ◽  
José Campos-Zumbado ◽  
Diana Hernández-Montoya ◽  
María Fernanda Lines-Gutiérrez
Keyword(s):  
Computed Tomography ◽  
3D Printing ◽  
Gold Standard ◽  
Exploratory Study ◽  
Cone Beam ◽  
Significant Difference ◽  
Software And Hardware ◽  
Bone Structures ◽  
Senior Students ◽  
Stereolithographic Models

A descriptive and exploratory study was carried out with the aim of proposing and validating an open protocol for making 3D impressions of stereolithographic models, which is available to professionals in the area of Dentistry. Nine operators (senior students of the Dentistry degree), without previous experience in the use of software and hardware for 3D printing, divided into two groups were trained through theoretical and practical sessions. The A worked with three helical tomographies (TAC) and the B with three cone beam computed tomography (CBCT), all in DICOM format, converted to STL files. In total, 99 bone structures corresponding to 33 jaws, 33 axis and 33 facial masses-skull bases were analyzed, and a total of 33 jaws were printed in PLA (polylactic acid filament). At the end of the study, no statistically significant difference was found in the implementation of the proposed protocol between the operators, the measurements of the pieces printed by each of them, the gold standard, the TAC and the CBCT, with which not only validated the protocol, but it was possible to determine the resources necessary to carry out this type of 3D printing.

Determining the Accuracy of the Mandibular Canal Region in 3D Biomodels Fabricated from CBCT Scanned Data: A Cadaveric Study

2019 ◽  
Vol 15 (7) ◽  
pp. 645-653 ◽  
Author(s):  
Syed Yusoff Alzawawi Syed Abd Fattah ◽  
Firdaus Hariri ◽  
Phrabhakaran Nambiar ◽  
Zulkiflee Abu Bakar ◽  
Zainal Ariff Abdul Rahman
Keyword(s):  
Computed Tomography ◽  
Gold Standard ◽  
Mandibular Canal ◽  
Mean Value ◽  
Cone Beam ◽  
Cross Sectional ◽  
Measurement Protocol ◽  
Significant Difference ◽  
The Mean ◽  
Using Data

Objective:To validate the accuracy of the mandibular canal region in 3D biomodel produced by using data obtained from Cone-Beam Computed Tomography (CBCT) of cadaveric mandibles.Methods:Six hemi-mandible samples were scanned using the i-CAT CBCT system. The scanned data was transferred to the OsiriX software for measurement protocol and subsequently into Mimics software to fabricate customized cutting jigs and 3D biomodels based on rapid prototyping technology. The hemi-mandibles were segmented into 5 dentoalveolar blocks using the customized jigs. Digital calliper was used to measure six distances surrounding the mandibular canal on each section. The same distances were measured on the corresponding cross-sectional OsiriX images and the 3D biomodels of each dentoalveolar block.Results:Statistically no significant difference was found when measurements from OsiriX images and 3D biomodels were compared to the “gold standard” -direct digital calliper measurement of the cadaveric dentoalveolar blocks. Moreover, the mean value difference of the various measurements between the different study components was also minimal.Conclusion:Various distances surrounding the mandibular canal from 3D biomodels produced from the CBCT scanned data was similar to that of direct digital calliper measurements of the cadaveric specimens.

scholarly journals Temporomandibular Joint Osseous Morphology of Class I and Class II Malocclusions in the Normal Skeletal Pattern: A Cone-Beam Computed Tomography Study

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 541
Author(s):  
Xiao-Chuan Fan ◽  
Lin-Sha Ma ◽  
Li Chen ◽  
Diwakar Singh ◽  
Xiaohui Rausch-Fan ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Temporomandibular Joint ◽  
Cone Beam Computed Tomography ◽  
Class Ii ◽  
Class I ◽  
Cone Beam ◽  
Glenoid Fossa ◽  
Linear Measurements ◽  
Significant Difference ◽  
Skeletal Pattern

(1) Background—The aim of the present study was to evaluate the correlation between the temporomandibular joint (TMJ) osseous morphology of normal skeletal pattern individuals with different dental malocclusions by using cone-beam computed tomography (CBCT). (2) Methods—The CBCT images of bilateral TMJs in 67 subjects with skeletal class I and average mandibular angle (26 males and 41 females, age range 20–49 years) were evaluated in this study. The subjects were divided into class I, class II division 1, and class II division 2 according to the molar relationship and retroclination of the maxillary incisors. Angular and linear measurements of TMJ were evaluated and the differences between the groups were statistically analyzed. (3) Results—Intragroup comparisons showed statistical differences for articular eminence inclination, the width of the glenoid fossa, the ratio of the width of the glenoid fossa to the depth of the glenoid fossa, the condylar angle, and the intercondylar angle between the malocclusion groups. The measurements of the glenoid fossa shape showed no significant difference between the left and right sides. Females showed more differences in the morphological parameters of TMJ between the three malocclusion groups than the males. (4) Conclusion—The present study revealed differences in the TMJ osseous morphology between dental class I and class II malocclusions in the normal skeletal pattern.

scholarly journals The Effect of Implant-Induced Artifacts on Interpreting Adjacent Bone Structures on Cone-Beam Computed Tomography Scans

2018 ◽  
Vol 27 (1) ◽  
pp. 10-14 ◽  
Author(s):  
Rachel A. Sheridan ◽  
Yi-Chen Chiang ◽  
Ann M. Decker ◽  
Pimchanok Sutthiboonyapan ◽  
Hsun-Liang Chan ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Cone Beam ◽  
Computed Tomography Scans ◽  
Bone Structures

Automatic Knot Detection in Coarse-Resolution Cone-Beam Computed Tomography Images of Softwood Logs

2019 ◽  
Vol 69 (3) ◽  
pp. 185-187
Author(s):  
Magnus Fredriksson ◽  
Julie Cool ◽  
Stavros Avramidis
Keyword(s):  
Computed Tomography ◽  
Exploratory Study ◽  
Ct Scanning ◽  
Detection Algorithm ◽  
Cone Beam ◽  
X Ray ◽  
Coarse Resolution ◽  
Computed Tomography Images ◽  
X Ray Computed ◽  
Accurate Position

Abstract X-ray computed tomography (CT) scanning of sawmill logs is associated with costly and complex machines. An alternative scanning solution was developed, but its data have not been evaluated regarding detection of internal features. In this exploratory study, a knot detection algorithm was applied to images of four logs to evaluate its performance in terms of knot position and size. The results were a detection rate of 67 percent, accurate position, and inaccurate size. Although the sample size was small, it was concluded that automatic knot detection in coarse resolution CT images of softwoods is feasible, albeit for knots of sufficient size.

scholarly journals PREVALENCE OF MANDIBULAR ASYMMETRY IN SKELETAL CLASS I ADULT PATIENTS

2014 ◽  
Vol 2 (2) ◽  
pp. 189 ◽  
Author(s):  
Bruno Frazão Gribel ◽  
Guilherme Thiesen ◽  
Tássia Silvana Borges ◽  
Maria Perpétua Mota Freitas
Keyword(s):  
Computed Tomography ◽  
Calculation Method ◽  
Significant Error ◽  
Adult Patients ◽  
Class I ◽  
Cone Beam ◽  
Skeletal Class ◽  
Mandibular Asymmetry ◽  
Computed Tomography Images ◽  
Significant Difference

AIM: The objective of this study was evaluating the prevalence of mandibular asymmetry in skeletal Class I adult patients. MATERIALS AND METHODS: The sample was composed by cone-beam computed tomography images of 250 skeletal Class I patients with age from 18 to 70 years old. The side deviation of mandibular asymmetry was evaluated (right and left), as well as the intensity of this asymmetry. People with gnathic deviation until 2mm were considered as patients with slight asymmetry; deviation between 2 and 5mm was considered moderate asymmetry and those higher than 5mm as severe asymmetries. The error calculation method was performed and there was not significant error in the measurements. To verify the association between the prevalence of mandibular asymmetry and the gender of individuals, the Χ2 was carried out and the significant level adopted was 5% (p<0.05). RESULTS: The results showed that mandibular deviation occurred more frequently to the left side in both genders (male 56.5% e female 58.2%), without statistically significant difference between them (p=0.792). Besides, the prevalence of slight, moderate and severe asymmetries were, respectively 61%, 27% and 12% for males and 54%, 28% and 18% for female; and there was not statistically significant difference (p=0.366) between the gender of the sample evaluated. CONCLUSION: In this study, both deviation and intensity of mandibular asymmetry did not present preference regarding to the gender.

scholarly journals Knowledge Level of Iranian Dental Practitioners Towards Digital Radiography And Cone-Beam Computed Tomography

2021 ◽  
Vol 24 (2) ◽  
Author(s):  
Fatemeh Salemi ◽  
Abbas Shokri ◽  
Maryam Foroozandeh ◽  
Maryam Farhadian ◽  
Ayoub Yeganeh
Keyword(s):  
Computed Tomography ◽  
Radiation Dose ◽  
Digital Radiography ◽  
Cone Beam Computed Tomography ◽  
Work Experience ◽  
Further Education ◽  
Cone Beam ◽  
Knowledge Level ◽  
Dental Practitioners ◽  
Significant Difference

Objective: This study aimed to assess the knowledge level of Iranian dental practitioners about digital radiography(DR) andcone-beamcomputedtomography (CBCT). Material and Methods: In this crosssectional study, a researcher-designed questionnaire was administered among 180 general dentists and specialists. The questionnaire had three main domains of demographic information, fifteen questions about knowledge of DR (advantages, disadvantages, physical properties) and twenty six questions about knowledge of CBCT (indications, applications, advantages, route of knowledge acquisition). Data were analyzed using descriptive statistics, t-test and Pearson’s correlation coefficient. Results: Of 180 participants, 76 (42.2%) were females. The minimum, maximum and mean± standard deviation scores obtained in DR were 4, 14, and 9.031 ± 1.85 and in CBCT were 0,26 and 18.56 ± 4.81, respectively. In the CBCT domain, the participants had maximum knowledge about “low radiation dose” (72.8%) and minimum knowledge about the “role of CBCT in determination of bone density” (45%). In DR domain, the participants had maximum knowledge about “no need for radiographic films” (75.6%) and minimum knowledge about “not requiring manual processing” (15.6%). Overall, participants had higher level of knowledge about CBCT than DR. An inverse correlation was noted between age and work experience with the number of correct answers. However, no significant difference was noted in the knowledge level of males and females regarding CBCT or DR (p = 0.233 and p = 0.227, respectively). Conclusions: further education seem imperative for dentists in this respect for more efficient diagnosis and treatment planning, minimize patient radiation dose and save time and cost.   Keywords Digital radiography; Cone-Beam computed tomography; Knowledge; Dentists.

scholarly journals Comparison of the Hounsfield Unit Values Obtained From Cone-Beam Computed Tomography (CBCT) and Multidetector Computed Tomography (MDCT) Images for Different Bone Densities

2021 ◽  
Vol 7 (2) ◽  
Author(s):  
Atefeh Khavid ◽  
Mojgan Sametzadeh ◽  
Mostafa Godiny ◽  
Mohammad Mehdi Moarrefpour
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Pearson Correlation ◽  
Hounsfield Unit ◽  
Cone Beam ◽  
Ct Scanner ◽  
Significance Level ◽  
Dental Practitioners ◽  
Significant Difference ◽  
The Mean

Background and objective: In recent years, cone-beam computed tomography (CBCT) has become a key diagnostic tool in dentistry. CBCT can provide 3D images of the maxillofacial area to help dental practitioners in diagnosis and treatment, especially implant placement and treatment of pathogenic lesions. This study aimed to compare the Hounsfield Unit (HU) values obtained from CBCT images for bones of different densities with the corresponding HU values from MDCT images. Materials and methods: cube-shaped bone blocks of identical size were cut from the middle section of the cow ribs and femur area such that they had a layer of cortical bone in their buccal, lingual, and top surfaces and trabecular bone in the middle. MDCT scans were performed using a Somatom Sensation Ct Scanner. After determining HU from the results of these scans, nine suitable specimens from different ranges of HU were chosen for comparison. HU of the CBCT images was computed by the dedicated software of the CBCT machine. Finally, HU values obtained from MDCT and CBCT were compared. Data analysis was performed using SPSS version 25 at the 0.05 significance level. Results: The results showed a statistically significant difference between the mean HU from MDCT images and the mean HU from CBCT images (P<0.05). For similar specimens, CBCT produced higher mean HU values than MDCT. The Pearson correlation test detected a significant direct relationship between the HU values of specimens in MDCT and CBCT (P<0.05). Conclusion: For the tools and software used in this study, there was no significant difference between the HU values obtained from MDCT and CBCT, but the mean HU obtained from CBCT was higher than that from MDCT.

scholarly journals Evaluation of the Prevalence of Concha Bullosa in Cone-Beam Computed Tomography Images

2020 ◽  
Vol 12 (3) ◽  
pp. 93-96
Author(s):  
Nasim Shams ◽  
Bahareh Shams ◽  
Zahra Sajadi
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Middle Turbinate ◽  
Cone Beam ◽  
P Value ◽  
Concha Bullosa ◽  
Computed Tomography Images ◽  
Significant Difference ◽  
And Gender ◽  
Sinus Ostium

Background: The ostiomeatal complex (OMC) is not a separate anatomical structure although it is a functional unit of structures, including the middle meatus, uncinate process, infundibulum, maxillary sinus ostium, ethmoidal bulla, anterior ethmoid sinus ostium, and frontal recess. Concha bullosa is the pneumatization of the concha, which is one of the most common anatomical variations in the middle turbinate. Methods: This study was conducted using the cone-beam computed tomography (CBCT) images of 172 patients in the archives of the Department of Oral and Maxillofacial Radiology, Dentistry School, Ahvaz Jundishapur. Patient information including age and gender, presence or absence of concha bullosa, the involved side (left or right), and its type (i.e., extensive, lamellar, and bulbous) were collected in the information form. Finally, the chi-square test (with SPSS, version 22) was used to analyze the data, and P value less than 0.05 was considered statistically significant. Results: Patients with and without concha bullosa were 39.1 and 41.7 years, respectively, but it was no significant difference in terms of age (P = 0.321). Out of 52 patients with concha bullosa, 19 (36.5%) cases were males and 33 (63.5%) of them were females. The prevalence of concha bullosa was higher for the bilateral side (20 patients, 38.5%, P = 0.000). The prevalence of bulbulsand lamellar-shape was nearly the same (32.7% and 30.8%, respectively). Eventually, the extensive shape with 36.5% was more frequent for the shape of concha bullosa (P = 0.000). Conclusions: The prevalence of concha bullosa was high. There was no significant difference in terms of age (P = 0.321) and gender (P = 0.058) of patients with concha bullosa. The extensive type and the bilateral appearance of concha bullosa were more significant (P = 0.000).

scholarly journals Evaluation of version of acetabular component following total hip replacement on conventional radiograph and computed tomography

2020 ◽  
Vol 27 (2) ◽  
pp. 179-185
Author(s):  
Manish Raj ◽  
Ashish Jaiman ◽  
Rajesh Kumar Chopra
Keyword(s):  
Computed Tomography ◽  
Ct Scan ◽  
Total Hip Replacement ◽  
Gold Standard ◽  
Hip Replacement ◽  
Regression Line ◽  
Patient Positioning ◽  
Acetabular Version ◽  
Total Hip ◽  
Significant Difference

Background/Purpose: Total hip replacement (THR) is considered as one of the most successful orthopedic procedures. However, improperly placed components can lead to instability and accelerated wear. Acetabular cup inclination can be very well accessed by anteroposterior pelvis X-rays; for acetabular version assessment, computed tomography (CT) scan is the gold standard. CT scan is not readily available at many centers and the surgeon has to rely on X-ray methods for evaluation of acetabular version to audit results and to predict behavior of the surgical intervention. This prospective study was undertaken to compare Woo and Morrey’s and ischiolateral methods of assessment of acetabular version on cross-table lateral radiographs with CT assessment and to assess the validity of radiographic methods with respect to CT scan method. Material and methods: A prospective follow-up study was conducted for 18 months’ duration (October 2016 to March 2018) on 30 adult patients who underwent THR surgery. Cross-table lateral radiograph was obtained at 3 and 6 weeks in the postoperative period. Two observers made each observation at two different points of time. CT scan was performed at 3 weeks. Version as measured by radiographs and CT scan was recorded. Results: The major overlap in the distribution of the values of the Woo and Morrey method suggests that there is no significant difference between the observations. Distribution of the values of the ischiolateral view and the CT scan value distributions have a very small overlap and hence suggest a strong significant difference between the two. Conclusion: In this study, Woo and Morrey’s method and ischiolateral method of assessment of acetabular version were compared with CT assessment. We found that in Woo and Morrey’s method, values were comparable to CT scan values, when put on regression line. However, in situation of change in patient positioning, namely hip stiffness in contralateral hip, measurement of component changed in series of radiography due to differences in pelvis tilt. So, in these circumstances, we can use ischiolateral method which can give consistent measurement. But it will not be in concordance with CT scan values and Woo and Morrey values, as represented in regression line. The high intra-class correlation coefficients for both intra- and inter-observer reliability indicated that the angle measured with these methods is consistent and reproducible for multiple observers. CT, however, be considered as gold standard for measurement owing to control over pelvic rotation and/or tilt/patient positioning.

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