Accuracy Of Linear Measurements Research Articles

Tomographic Planning of Dental Implants Using a Smartphone: Linear Measurements and Implant Selection-A Cross-Sectional Study.

This study assessed the accuracy of linear measurements and dental implant selection performed in a smartphone application compared to a computer software. Forty-four DICOM files from partially edentulous patients in the posterior region of the mandible were evaluated by three trained and calibrated examiners. Images were analyzed using three visualization methods: cross-sectional view (CScr) and coronal (CSco) plane using the CS 3D Imaging software, and coronal (DRco) plane using the DroidRender smartphone application. For the purpose of standardization, measurements of bone width and height were taken in the edentulous posterior region of the mandible, 10 mm posterior to the mental foramen. Dental implant selection was made according to Straumann® Standard implant catalog 2022/2023. Linear measurements were compared using the ANOVA test for repeated measurements and implant selection was compared using the Friedman test. Statistical analysis was performed using the SPSS software, considering a significance level of 5%. Linear measurements showed a statistically significant difference for bone width (p = 0.030), but not for height (p = 0.685). The choice of implant was not influenced by the visualization method (p = 0.614). It is possible to suggest the use of smartphone applications as an additional diagnostic tool for DICOM evaluation and dental implant planning in the posterior region of the mandible. Smartphone applications allow an assessment not limited to 2D images or to static environments. Therefore, information exchange and diagnostic opinion in emergency situations may be facilitated.

Assessing the reliability and accuracy of sex estimation models utilizing sternal morphometry derived from computed tomography in the Ghanaian population

Sex estimation models are specific to populations and cannot be generalized due to genetic and environmental variabilities. This retrospective cross-sectional study, conducted between January and September 2023 at the Tamale Teaching Hospital, included 119 (50.9 %) females and 115 (49.1 %) males aged 23–82 years. Measurements, including manubrium length (M), manubrium width (MW), sternal body length (B), combined manubrium and sternal body lengths (CL), corpus sterni width at first sternebrae (CSWS1), and corpus sterni width at third sternebrae (CSWS3), were obtained from Computerized Tomographic (CT) images of the sternum using DICOM Viewer, accurate to 0.1 cm. Subsequently, sternal area (SA) and sternal index (SI) were calculated. Univariable and stepwise multivariable discriminant function analysis (DFA) and logistic regression (LR) models were developed using a training sample (70 %), and cross-validation was performed on a holdout sample (30 %). Results showed that the linear measurements, excluding M, and sternal area were higher in males than females (P<0.001), while the sternal index was <50 % in males but >50 % in females (P<0.001). Univariable sex estimation accuracies, in cross-validation, ranged from 43.7 % to 92.9 % in DFA and 50.0–92.9 % in LR. For multivariable models, the accuracy ranges were 92.9–94.3 % in DFA and 91.6–93.0 % in LR. The sternal body length was the most accurate at 90.1 % in DFA and 90.2 % in LR, with lower sex bias (male-female) in LR than in DFA (-0.1 vs. 8.7). The sternum proves valuable for sex estimation, with sternal body length as the most accurate linear measurement. However, multivariable models, particularly LR, demonstrate higher accuracy compared to DFA.

Reliability and validity of handheld structured light scanners and a static stereophotogrammetry system in facial three-dimensional surface imaging

Several new systems for three-dimensional (3D) surface imaging of the face have become available to assess changes following orthognathic or facial surgery. Before they can be implemented in practice, their reliability and validity must be established. Our aim, therefore, was to study the intra- and inter-system reliability and validity of 3dMD (stereophotogrammetry), Artec Eva and Artec Space Spider (both structured light scanners). Intra- and inter-system reliability, expressed in root mean square distance, was determined by scanning a mannequin’s head and the faces of healthy volunteers multiple times. Validity was determined by comparing the linear measurements of the scans with the known distances of a 3D printed model. Post-processing errors were also calculated. Intra-system reliability after scanning the mannequin’s head was best with the Artec Space Spider (0.04 mm Spider; 0.07 mm 3dMD; 0.08 mm Eva). The least difference in inter-system reliability after scanning the mannequin’s head was between the Artec Space Spider and Artec Eva. The best intra-system reliability after scanning human subjects was with the Artec Space Spider (0.15 mm Spider; 0.20 mm Eva; 0.23 mm 3dMD). The least difference in inter-system reliability after scanning human subjects was between the Artec Eva and Artec Space Spider. The most accurate linear measurement validity occurred with the Artec Space Spider. The post-processing error was 0.01 mm for all the systems. The Artec Space Spider is the most reliable and valid scanning system.

Accuracy of linear measurements for implant planning based on low-dose cone beam CT protocols: a systematic review and meta-analysis.

The aim of this systematic review was to verify the accuracy of linear measurements performed on low-dose CBCT protocols for implant planning, in comparison with those performed on standard and high-resolution CBCT protocols. The literature search included four databases (Pubmed, Web of Science, Embase, and Scopus). Two reviewers independently screened titles/abstracts and full texts according to eligibility criteria, extracted the data, and examined the methodological quality. Risk of bias assessment was performed using the Quality Assessment Tool For In Vitro Studies. Random-effects meta-analysis was used for pooling measurement error data. The initial search yielded 4684 titles. In total, 13 studies were included in the systematic review, representing a total of 81 samples, while 9 studies were included in the meta-analysis. The risk of bias ranged from medium to low. The main results across the studies indicate a strong consistency in linear measurements performed on low-dose images in relation to the reference methods. The overall pooled planning measurement error from low-dose CBCT protocols was -0.24 mm (95% CI, -0.52 to 0.04) with a high level of heterogeneity, showing a tendency for underestimation of real values. Various studies found no significant differences in measurements across different protocols (eg, voxel sizes, mA settings, or dose levels), regions (incisor, premolar, molar) and types (height vs. width). Some studies, however, noted exceptions in measurements performed on the posterior mandible. Low-dose CBCT protocols offer adequate precision and accuracy of linear measurements for implant planning. Nevertheless, diagnostic image quality needs must be taken into consideration when choosing a low-dose CBCT protocol.

Creation of virtual models of buildings for the formation of unified real estate complexes as a part of land and cadastral works

The article presents the results of the research project to create 3D models of buildings from digital images using a smartphone camera and the Agisoft Photoscan Professional software, comparing them with data obtained with an electronic total station. The authors outlined the possibilities of using the described technologies for the development of 3D cadastre, which can simplify creation of virtual models through the adaptation of modern widgets. The technological sequence of creating a building model in a virtual format and the accuracy of linear measurements are considered here. The paper contains the results of determining the area and the value of the mean square error. The authors presume that these technologies can be used for the development of 3D cadastre in the formation of unified real estate complexes as a part of land cadastral works, as well as for design and reconstruction solutions.

Effect of metal artifact removal modes on the accuracy of linear measurement around titanium implants by applying different voltages: an original article

BackgroundThis study aims to evaluate the effects of the artifact removal algorithm on linear measurements of the buccal cortical plate by altering the voltage.MethodsTen titanium fixtures were inserted at the site of central, lateral, canine, premolars and molars of dry human mandibles. Vertical height of buccal plate was measured using a digital caliper as a gold standard. Mandibles were scanned with 54 and 58 kVp. Other parameters were constant. Images were reconstructed with none, low, medium and high artifact removal modes. Two Oromaxillofacial radiologists evaluated and measured the buccal plate height using Romexis software. Statistical package for the social sciences (SPSS) version 24 was used for data analysis.ResultsIn medium and high modes, the difference between 54 and 58 kVp was significant (p < 0.001). No significance was noted by using low ARM (artifact removal mode) at the 54 kVp and 58 kVp.ConclusionUsing artifact removal in low voltage decreases the accuracy of linear measurement and buccal crest visibility. By using high voltage, artifact removal would have no significant effect on accuracy of linear measurements.

Determination of permanent corrections of ball reflectors

Today, there are many manufacturers of triple-prism, spherical reflectors with different mechanical characteristics. That is why there is a problem of matching the signal reflection center with the geometric one. The purpose of this work is to evaluate the methods of determining permanent corrections of electronic tacheometers, ball reflectors and to develop recommendations for their use. Method. To determine the instrument correction, a displacement interferometer is used. It contains a two-frequency He-Ne laser with a wavelength of l = 0.63 μm (red range). The study compared the results of length measurements by an interferometer and an electronic total station with a ball reflector. This allowed determining the instrument correction. The research defined the constant correction of reflectors and total stations on the phase section of the field base using the method of created linear observations. Results. Experimental studies of ball reflectors of various manufacturers and Leica electronic tacheometers were conducted. The determination of constant instrument corrections of the total station and reflector using the displacement interferometer can be performed with an accuracy of 0.1 mm. This significantly depends on the accuracy of measuring lines with the total station. The use of ball reflectors with a built-in triple prism allows significant increase of distance measurement accuracy by reducing centering errors, considering the constant instrument correction (up to 0.4 mm for Leica 1201 total stations). Scientific novelty. The methods of determining permanent corrections of ball reflectors and total stations were investigated. The proposed method determines the measurement interval length with the exception of systematic constant correction of the electronic total station and reflector. Practical relevance. The use of ball reflectors is recommended for quick and unambiguous installation at points, convenience of their use for monitoring observations, as well as for increasing the accuracy of linear measurements due to the reduction of centering errors. In order to achieve high-precision measurements of short lines, it is recommended, according to the performed studies, to carefully determine the constant correction of the total station and ball prisms. This makes it possible to increase the accuracy of line measurements at least three times compared to the declared accuracy of the total station manufacturer.

Investigation of the effect of slice thickness and Kvp changes on the accuracy of linear measurements in CBCT: In vitro study

Investigation of the effect of slice thickness and Kvp changes on the accuracy of linear measurements in CBCT: In vitro study

EXPERIENCE OF OBTAINING INITIAL DATA FROM GOOGLE EARTH TO BUILD A DIGITAL TERRAIN MODEL

The Google Earth system is widely available, which allows to collect geographic spatial information both on a commercial basis and for own needs. Geodetic measurements are accompanied by measurement errors, they are divided into rough, systematic and random. Systematic errors always distort the measurement result in any direction. Systematic errors are tried to be eliminated by introducing amendments. The analysis of publications shows that the question of obtaining data from the Google Earth system has interested many researchers. Some came to the conclusion that it makes no sense to use geospatial height data, but the use of 2-D data requires research. The relevance is substantiated. The purpose of this article is to confirm the hypothesis that the Google Earth system provides precisely the systematic errors in finding distances so that by introducing linear corrections it is possible to increase the accuracy of linear measurements in this system. The order of the experiment: 1) to take several places (territories) located in different parts of the country; 2) in the Google Earth, to find objects with clear contours near the experimenter's location; 2) to measure distances using the Google Earth; 3) to take screenshots of the measured areas; 4) to measure the distance with a tape measure; 5) to calculate the difference; 6) to repeat the experiment in another part of the territory; 8) to calculate the arithmetic mean (using MS Excel); 9) to calculate the standard deviation (using MS Excel). Three territories located in the northern part of eastern Ukraine were considered. 10 experiments were carried out in each territory. The hypothesis (that the Google Earth system gives systematic errors in finding distances) has been proven. Now, through the introduction of linear corrections, it is possible to increase the accuracy of linear measurements in this system. Keywords: Google Earth, systematic measurement errors, digital model of the situation, distance measurement.

Comparison of the accuracy of linear measurements in CBCT images with different field of views

This study sought to investigate the effect of the field of view (FOV) on linear measurements of cone beam computed tomography (CBCT) images. Methods: In this in vitro study, five dry human skulls were used. After using red wax to simulate soft tissue, the skulls were scanned using Galileos CBCT scanner (Sirona, Bensheim, Germany) with exposure parameters of 85 kVp and 21 mAs and voxel size of 0.280 mm; once with FOV of 15 cm × 8 cm and once again with 15 cm × 15 cm. The measured distances were the distance between the center of the bilateral mental foramen in the axial view (MM), the distance between the alveolar crest and the mandibular inferior border in the sagittal view on the midline (CB), and the depth of the socket of the left mandibular central incisor (L1). Descriptive statistics as well as Pearson’s correlation coefficient were used for statistical analysis (α = 0.05) using SPSS software (v. 25, IBM, NY, USA). Results: The measurements obtained with small and large FOV and with the dry skull were not significantly different (p &gt; 0.05). The measurements obtained in small FOV had excellent correlation coefficient when compared with those obtained with the dry skull, with values of 0.890 for MM, 0.954 for CB, and 0.921 for L1 (p &lt; 0.001). The measurements in large FOV also had excellent correlation coefficient when compared with those on the dry skull, with values of 0.894 for MM, 0.949 for CB, and 0.902 for L1 (p &lt; 0.001). Conclusion: According to our findings, linear measurements obtained by CBCT scans in small and large FOVs were not significantly different than those on dry skulls. Since the linear measurements are accurate regardless of FOV size, selection of FOV must be based on patient factors, such as area of interest and radiation dose.

High-precision displacement measurement algorithm based on a depth fusion of grating projection pattern.

Displacement measurement based on an image recognition algorithm has more advantages in the field of displacement measurement. Due to the uncertainty of image location, the accuracy of the displacement measurement algorithm studied in the previous stage is limited. To improve the accuracy of image-type displacement measurement, a high-precision displacement measurement algorithm based on depth fusion of the grating projection pattern is proposed. First, a line-scan image sensor and parallel light source are placed on both sides of the calibration grating. The marking pattern on the calibration grating is projected onto the image sensor through illumination of the parallel light source to realize the projection imaging. Then, the centroid algorithm is used to calculate the centroid of each line in the collected image, and the mean value of the centroid group is determined. Finally, a linear function is used to fit multiple centroids to calculate the endpoints of the subdivision region, and the subdivision operation is carried out according to a ratio algorithm. To test the performance of the proposed algorithm, a linear displacement measurement device with a 250 mm range and an angular displacement measurement device with a 100 mm diameter grating are both used for experiments. After testing, the linear measurement accuracy of the proposed algorithm is improved from 4.63 to 1.26 µm, and the angular displacement measurement accuracy is enhanced from 8.87 to 2.88''. The research in this paper provides a theoretical basis for high-performance displacement measurement.

Оптимизация расположения деформационных марок при построении сети в виде линейной пространственной засечки

The authors present the assessment of determining the deformation marks’ coordinates accuracy at constructing a network in the form of a linear spatial intersection. Using the distance between the control points and deformation marks; their coordinates are defined. The root- and general mean-square errors in determining the coordinates arising from the faults in measuring the lengths and depending on the shape of the spatial intersection are calculated. Computational mistakes enable assessing the possibility of obtaining the desired results at designing a network of deformation marks with an accuracy that meets the requirements of regulatory documents, and taking the expected accuracy of linear measurements into account. Selecting the marks is shown by the example of an elementary model. Two computer programs for that purpose were developed. The convergence of the results obtained in the course of the programs and theoretical modeling indicates the correct operation of the software. The developed algorithm and pro-grams enable optimizing the location of deformation marks at designing a network.

Accuracy of an electrical impedance device in estimation of remaining dentin thickness vs cone beam computed tomography.

The objective of this study is to compare the estimated values of remaining dentin thickness (RDT) recorded by a newly introduced electrical impedance device (Prepometer) with cone beam computed tomography (CBCT) and histological in situ measurement. A total number of thirty human molars were used in this study. A deep class I cavity was prepared. The RDT for each cavity was measured with Prepometer in three different points (mesial, middle, and distal). Same specimens were imaged with high-resolution Cone Beam Computed Tomography CBCT (0.1mm voxel size) using I CAT next Generation Machine (Imaging Science International, Hatfield, PA, USA), to provide the highest possible accuracy of linear measurements. Finally, the specimens were vertically sectioned parallel to the long axis of the tooth in a mesiodistal direction splitting the cavity into two halves through its center. Then, the actual RDT of each half will be measured in the same three points using a digital caliper. The outcome of one-way ANOVA revealed that there was no significant difference in RDT values measured by prepometer device, CBCT, or histological sectioning methods (p > 0.05). Within the limitations of this laboratory study, prepometer seems to be a potential non-invasive accurate measuring tool for RDT. Based on the findings of this study, the Prepometer can be considered as an easily handled and less-expensive method compared to CBCT to evaluate the RDT. Also, it can be used in dental schools and with less-experienced operators to avoid traumatic exposures of the dental pulp.

Effect of Different Voxel Sizes on Accuracy of 2D and 3D Mandibular Linear Measurements Using CRANEX® 3D Cone Beam Computed Tomography Machine: Preclinical Study

Aim To assess the accuracy of linear measurement obtained from CBCT images in 3D volumetric rendering and multiplanar slices with different voxel sizes. Methodology: 9 mandibles with twelve radioopaque markers fixed on each one were imaged using CRANEX® 3D CBCT machine. Each mandible was imaged twice with voxel sizes 250 μm and 350 μm. 2D and 3D linear measurements from CBCT images were compared to the real physical measurements taken by a digital caliper. Software measurements were recorded twice by the principal investigator and once by the supervising professor. Intra- and inter-observer agreements were assessed using Intra-Class Correlation Coefficient (ICC). SPSS®IBM Version 24 and MedCalc® version 12.1 for Windows were used for statistical analysis. Results: CBCT 2D measurements with voxel sizes of 250μ and 350μ showed a mean difference= 0 mm both with 95% of difference being -0.6 mm above or 0.7mm below and-0.5 mm above or 0.6 mm below the Gold Standard respectively. CBCT 3D measurements with voxel sizes of 250μ and 350μ showed a mean difference= 0 mm both with 95% of difference being -0.5 mm below or 0.5 mm above and -0.6 mm above or 0.7 mm below the Gold Standard. Intra-observer and inter-observer reliability regarding all measurements showed excellent agreement. Conclusions: 2D and 3D measurements driven from CBCT images with voxel size of 350 μ are accurate as measurements driven from CBCT images with voxel size of 250 μ with less radiation delivered to the patient. 2D and 3D CBCT measurements driven from CBCT are reliable.

Accuracy of linear measurements performed with two different software in cone-beam computed tomography scans of dry human mandibles

Objectives: The present study aimed to assess the accuracy of linear measurements performed with two different CBCT software .(Romexis® software and ONDEMAND 3 D software). Methods: The sample consisted of 15 human mandibles marked with radiopaque markers of gutta-percha balls (size 80, 1.5 mm long) which were glued on the marked anatomical landmarks with cyanoacrylate gel, ten linear measurements were conducted on the dry mandibles using digital caliper to provide gold standard meaurments.The mandibles were scanned by using Planmeca ProMax 3D Mid and images exported into digital imaging and communication in medicine (DICOM) format to a DVD then imported in to two software programs.The same ten linear measurements were conducted on the scanned images by using measure length tool of both romexis and Ondemand software programs. Results: Intra-examiner reliability of gold standard and image measurements were found to be excellent, Inter-examiner reliability of physical and Romexis® software was found to be excellent (ICC>0.9) and the Inter-examiner reliability of physical and ONDEMAND 3 D software was found to be poor (ICC <0.5) Conclusions: Romexis® software is more reliable method for planning surgical procedure in the dental practice than ONDEMAND 3 D software. Keywords: Linear measurements, CBCT, dry mandible and software programs.

A New Pipeline to Automatically Segment and Semi-Automatically Measure Bone Length on 3D Models Obtained by Computed Tomography.

The characterization of developmental phenotypes often relies on the accurate linear measurement of structures that are small and require laborious preparation. This is tedious and prone to errors, especially when repeated for the multiple replicates that are required for statistical analysis, or when multiple distinct structures have to be analyzed. To address this issue, we have developed a pipeline for characterization of long-bone length using X-ray microtomography (XMT) scans. The pipeline involves semi-automated algorithms for automatic thresholding and fast interactive isolation and 3D-model generation of the main limb bones, using either the open-source ImageJ plugin BoneJ or the commercial Mimics Innovation Suite package. The tests showed the appropriate combination of scanning conditions and analysis parameters yields fast and comparable length results, highly correlated with the measurements obtained via ex vivo skeletal preparations. Moreover, since XMT is not destructive, the samples can be used afterward for histology or other applications. Our new pipelines will help developmental biologists and evolutionary researchers to achieve fast, reproducible and non-destructive length measurement of bone samples from multiple animal species.

Accuracy of CBCT Linear Measurements to Determine the Height of Alveolar Crest to the Mental Foramen

Background: Detailed knowledge of the three-dimensional (3D) anatomical structures in precise treatment planning prior to implant placement is necessary. The choice of imaging techniques plays an important role in achieving the required information to measure exact dimensions. Cone beam computed tomography (CBCT) has increasingly been used for diagnosis and treatment in the fields of periodontology, endodontic, and orthodontics. It is also used as the preoperative evaluation of patients who are candidates for dental implant treatment. Dental implant placement is an important application of CBCT in dentistry. One of the features of CBCT is the possibility of changing the slice thickness while reviewing images. In this study, we examined the linear measurement accuracy of CBCT for determining the height of alveolar crest to the mental foramen in cross-sectional view with different slice thicknesses and in tangential view. Methods: We used five dry human mandibles in this study. Then the distance from the highest tip of alveolar crest to the upper border of mental foramen was measured by digital caliper (as gold standard) and on CBCT images in cross sectional view with 1, 3, 5, 7 and 9 mm slice thicknesses and in tangential view. Data were analyzed using IBM SPSS Statistics software version 22, paired t test, and inter class correlation. Results: Data were collected by evaluation of 5 dry mandible and 240 measurements. There were significant differences only in tangential view and 1 mm slice thickness option in cross-sectional view with the gold standard (P=0.003 and P=0.018 respectively). The results did not show any differences between the observers (P&lt;0.001). Conclusions: Our results indicated that cross-sectional view is more accurate than tangential view, and 3 and 5 mm slice thicknesses are preferred for measurement.

Accuracy of Linear Measurements of Ultra-Low Dose Cone Beam Computed Tomography and Digital Panoramic Radiography Performed on Mandibular Anaesthetic Landmarks Versus Real Mandibular Measurements: A Diagnostic Accuracy Study

Aim: This study was conducted to evaluate the accuracy of linear measurements performed on mandibularanaesthetic landmarks obtained by ultra-low-dose cone beam computed tomography and digital panoramicradiography in comparison with real measurement on dry mandible.Method: A total number of nine dry human mandibles were selected and mandibular anaesthetic landmarkswere marked using gutta-percha. The dry mandibles were submitted for digital panoramic radiography andcone beam computed tomography with mini-dose parameters using the SOREDEX CRANEX™ 3Dx unit,linear measurements were performed on SCANORA Lite image viewer and on Demand 3D viewer. The reallinear measurements were measured using digital caliper.Results: There was a statistically significant difference in all measurements performed on digital panoramicradiographs,reformatted panoramic images underestimate real linear vertical measurements withoutsignificant difference, the absolute error for the cross-sectional views of CBCT ranged from 0.0001 to1.44mm for mandibular foramen linear measurements, using mini-dose parameters did not affect imagequality nor measurements accuracy.Conclusions: Linear measurements driven from CBCT cross-sectional images using On Demand softwareare accurate and have the lowest error value; therefore it is considered one of the most important imagingmodality for preoperative surgical site assessment.

USING 3D-MODELLING METHODS DURING ACUTE HEART INJURY EXAMINATION

Despite the fact that the classical methods of acute trauma research are well studied and widely used in forensic medicine, in recent years in the world and domestic forensic practice are increasingly introduced modern computer technology and three-dimensional spatial modeling, which significantly complement and improve visualization of bodily injuries, as well as increase the accuracy of identification of the weapon of injury.Aim of the work. Forensic identification of the stabbing-cutting tool found at the scene and seized by the investigating authorities, with the presence of stab wounds to the heart, using photogrammetry and 3D modeling of the wound canal in the heart muscle.Materials and methods. As the materials of the study were used barbed cutting tool and individual elements of the wound canal, which were examined using photogrammetry and subsequent 3D modeling for their compliance in the examination of acute heart injury.Research results. An example of using the method of 3D modeling is given and its advantages in comparison with classical methods used in forensic practice during the examination of bodily injuries in the forensic identification of stabbing-cutting tools are shown. It is shown that when comparing the 3D model of a knife blade provided by investigators, its length, width at the site of the greatest thickening and bevel of the blade created by photogrammetry and three-dimensional spatial modeling with 3D models of fragments of the wound canal of stab-cut heart damage, their full compliance. The measurement results obtained from 3D models of fragments of the wound canal with the help of computer programs "Agisoft Photoscan" and "3ds max" are an order of magnitude more accurate than the measurements provided by classical methods.Conclusions. The use of photogrammetry and modern 3D modeling technologies allows to obtain 3D models of the wound canal in the thickness of the heart muscle or any other parenchymal organ and stabbing-cutting tool, to make more accurate linear measurements and comparison of fragments of the wound canal with the probable injury tool compliance.The electronic archive of 3D models will allow to save the parameters of damages in their original form, use them during additional, repeated or commission examinations, virtual expert experiment, as well as send by e-mail for remote consultation and investigative bodies and juries for use during court hearings.

Linear measurements of CBCT superimposition

Objectives: To assess accuracy and reliability of linear measurements for analysis of CBCT superimposition and determine if linear measurements are enough without requiring advanced analytical tools. Methods: Pre and post-operative CBCT scans of 20 orthodontic cases were used for CBCT superimposition. The gold standard was linear CBCT measurements on the axial section of each separate scan (pre and post) before superimposition. Voxel based and point based superimposition were done using Dolphin 3D (Dolphin Imaging and Management, Chatsworth, California, USA), In Vivo (Anatomage, San Jose, California, USA), and Ondemand 3D (Ondemand 3D; Cybermed Co., Seoul, Korea). Analysis of the superimposition was obtained on axial section of the superimposed models. Results were compared to the gold standard using error assessment according to Dahlberg error, Bland &Altman method and intra-class correlation coefficient. Results: Dolphin side by side method showed 25.4% relative Dahlberg error (RDE), 4.28 limit of agreement (LOA) and 0.768 intra-class correlation coefficient (ICC). In-Vivo point method showed 26.75% RDE, 4.48 LOA and 0.87 ICC. Whereas In-Vivo volume showed 24.66% RDE, 4.15 LOA and 0.822 ICC. On Demand showed 28.44%, 4.78 LOA and 0.7 ICC. Intra observer reliability of all methods regardless of the observers are poor. Conclusion: There is weak accuracy of the linear measurements on axial plane of CBCT superimposed models and it is not recommended alone for analysis.