• Journal of Periodontal and Implant Science
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• v.42 no.2
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• pp.39-44
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• 2012

Purpose: Special care is necessary to avoid invading important anatomic structures during surgery when presurgical planning is made based on radiographs. However, none of these types of radiography represents a perfect modality. The purpose of this study was to determine the reliability of presurgical planning based on the use of two types of radiographic image (digital panoramic radiography [DPR] and cone-beam computed tomography [CBCT]) by beginner dentists to place implants, and to quantify differences in measurements between radiographic images and real specimens. Methods: Ten fresh cadavers without posterior teeth were used, and twelve practitioners who had no experience of implant surgery performed implant surgery after 10 hours of basic instruction using conventional surgical guide based on CBCT or DPR. Two types of measurement error were evaluated: 1) the presurgical measurement error, defined as that between the presurgical and postsurgical measurements in each modality of radiographic analysis, and 2) the measurement error between postsurgical radiography and the real specimen. Results: The mean presurgical measurement error was significantly smaller for CBCT than for DPR in the maxillary region, whereas it did not differ significantly between the two imaging modalities in the mandibular region. The mean measurement error between radiography and real specimens was significantly smaller for CBCT than for DPR in the maxillary region, but did not differ significantly in the mandibular region. Conclusions: Presurgical planning can be performed safely using DPR in the mandible; however, presurgical planning using CBCT is recommended in the maxilla when a structure in a buccolingual location needs to be evaluated because this imaging modality supplies buccolingual information that cannot be obtained from DPR.

• Journal of Periodontal and Implant Science
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• v.50 no.1
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• pp.28-37
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• 2020

Purpose: The aim of our study was to determine the prevalence and degree of lingual concavities in the first molar region of the mandible to reduce the risk of perforating the lingual cortical bone during dental implant insertion. Methods: A total of 163 suitable cross-sectional cone-beam computed tomography images of edentulous mandibular first molar regions were evaluated. The mandibular morphology was classified as a U-configuration (undercut), a P-configuration (parallel), or a C-configuration (convex), depending on the shape of the alveolar ridge. The characteristics of lingual concavities, including their depth, angle, vertical location, and additional parameters, were measured. Results: Lingual undercuts had a prevalence of 32.5% in the first molar region. The mean concavity angle was 63.34°±8.26°, and the mean linear concavity depth (LCD) was 3.03±0.99 mm. The mean vertical distances of point P from the alveolar crest (Vc) and from the inferior mandibular border were 9.39±3.39 and 16.25±2.44, respectively. Men displayed a larger vertical height from the alveolar crest to 2 mm coronal to the inferior alveolar nerve (Vcb) and a wider LCD than women (P<0.05). Negative correlations were found between age and buccolingual width at 2 mm apical to the alveolar crest, between age and Vcb, between age and Vc, and between age and LCD (P<0.05). Conclusions: The prevalence of lingual concavities was 32.5% in this study. Age and gender had statistically significant effects on the lingual morphology. The risk of lingual perforation was higher in young men than in the other groups analyzed.

• Journal of Periodontal and Implant Science
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• v.50 no.1
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• pp.48-55
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• 2020

Purpose: The purpose of this study was to utilize cone-beam computed tomography (CBCT) image analysis to obtain anatomical information related to the morphology of the incisive foramen to provide useful data regarding implant placement and clinical procedures such as anesthesia. Methods: The study included 167 patients who underwent CBCT scans over 20 years. Three components were measured: 1) the anteroposterior and mediolateral diameter of the incisive foramen, 2) the horizontal bone thickness anterior to the incisive foramen, and 3) the vertical bone height coronal to the incisive foramen. All measurements were expressed as mean±standard deviation and were analyzed by a single examiner. Results: The anteroposterior diameter of the incisive foramen was wider than the mediolateral diameter (P<0.001). The diameter of the incisive foramen in patients in whom the central incisors were present was smaller than that in those in whom at least one central incisor was absent, but no statistically significant difference between the groups was observed. The horizontal bone thickness in the patients with central incisors was statistically significantly larger than that in the patients without at least one central incisor (P<0.001). The same pattern was observed with regard to vertical height, but that difference was not statistically significant. Conclusions: The buccal bone thickness anterior to the incisive foramen was significantly decreased after central incisor loss. It is necessary to identify the morphology of the bone and the location of the incisive foramen via CBCT to avoid invasion of the incisive foramen and nasopalatine canal.

• Restorative Dentistry and Endodontics
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• v.40 no.1
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• pp.58-67
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• 2015

Objectives: This study aimed to compare the accuracy of conventional intraoral (CI) radiography, photostimulable phosphor (PSP) radiography, cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) for detection of strip and root perforations in endodontically treated teeth. Materials and Methods: Mesial and distal roots of 72 recently extracted molar were endodontically prepared. Perforations were created in 0.2, 0.3, or 0.4 mm diameter around the furcation of 48 roots (strip perforation) and at the external surface of 48 roots (root perforation); 48 roots were not perforated (control group). After root obturation, intraoral radiography, CBCT and MDCT were taken. Discontinuity in the root structure was interpreted as perforation. Two observers examined the images. Data were analyzed using Stata software and Chi-square test. Results: The sensitivity and specificity of CI, PSP, CBCT and MDCT in detection of strip perforations were 81.25% and 93.75%, 85.42% and 91.67%, 97.92% and 85.42%, and 72.92% and 87.50%, respectively. For diagnosis of root perforation, the sensitivity and specificity were 87.50% and 93.75%, 89.58% and 91.67%, 97.92% and 85.42%, and 81.25% and 87.50%, respectively. For detection of strip perforation, the difference between CBCT and all other methods including CI, PSP and MDCT was significant (p < 0.05). For detection of root perforation, only the difference between CBCT and MDCT was significant, and for all the other methods no statistically significant difference was observed. Conclusions: If it is not possible to diagnose the root perforations by periapical radiographs, CBCT is the best radiographic technique while MDCT is not recommended.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.4
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• pp.425-431
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• 2019

This clinical case report describes the digital workflow that combines a face scan, cone beam computed tomography and an intraoral scan to visualize the outcome of prosthodontic treatment in the anterior region. This approach improves communication between clinic, laboratory and patients. A patient with healthy general condition came for a restorative treatment to treat post-traumatic central incisors of maxilla. A virtual patient replica was made by incorporating a face scan, cone beam computed tomography and an intraoral scan. Design mockup of definitive restorations was shown to the patient and modified according to the patient's desire. This digital workflow facilitates the fabrication of optimal esthetic restorations, and enhances the predictability of outcome of restorations.

• Imaging Science in Dentistry
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• v.51 no.3
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• pp.251-260
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• 2021

Purpose: Dental implants are widely used for the rehabilitation of edentulous sites. This study investigated the occurrence of dental implant malpositioning as shown on post-implantation cone-beam computed tomography (CBCT) and to identify related factors. Materials and Methods: Samples with at least 1 malpositioned dental implant were collected from a central radiology clinic in Tehran, Iran from January 2017 to January 2019. Variables such as demographic characteristics, length and diameter of implants, type of implant, sites of implant insertion, different types of implant malpositioning problems (cortical plate perforation, interference with anatomical structures), angulation of the implant, and the severity of malpositioning were assessed. In addition, the incidence of implant fracture and over-drilling was evaluated. Data were statistically analyzed using the chi-square test, 1-sample t-test, and Spearman correlation coefficients. Results: In total, 252 patients referred for implant postoperative CBCT evaluations were assessed. The cases of implant malpositioning included perforation of the buccal cortical plate (19.4%), perforation of the lingual cortical plate (14.3%), implant proximity to an adjacent implant (19.0%), implant proximity to an adjacent tooth (3.2%), interference with anatomical structures(maxillary sinus: 18.3%, mandibular canal: 11.1%, nasal cavity: 6.3%, mental foramen: 5.6%, and incisive canal: 0.4%). Implant fracture and over-drilling were found in 1.6% and 0.8% of cases, respectively. Severity was categorized as mild (9.5%), moderate (35.7%), severe (37.7%), and extreme (17.1%), and 52.4% of implants had inappropriate angulation. Conclusion: CBCT imaging is recommended for detecting dental implant malpositioning. The most common and severe type of malpositioning was buccal cortex perforation.

• Imaging Science in Dentistry
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• v.48 no.4
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• pp.269-275
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• 2018

Purpose: The aim of this study was to evaluate the correlations between measurements made using panoramic radiography and cone-beam computed tomography (CBCT) based on certain anatomical landmarks of the jaws, with the goal of preventing complications due to inaccurate measurements in the pre-surgical planning phase of dental implant placement. Materials and Methods: A total of 56 individuals who underwent panoramic radiography and a CBCT evaluation before dental implant surgery were enrolled in the study. Measurements were performed to identify the shortest vertical distance between the alveolar crest and neighboring anatomical structures, including the maxillary sinus, nasal floor, mandibular canal, and foramen mentale. The differences between the measurements on panoramic radiography and CBCT images were statistically analyzed. Results: Statistically significant differences were observed between the measurements on panoramic radiography and CBCT for all anatomical structures (P<.05). The correlation coefficients (r) between the paired samples obtained from panoramic radiography and CBCT were closely correlated (P<.05), with r values varying from 0.921 and 0.979 for different anatomical regions. Conclusion: The results of this study support the idea that panoramic radiography might provide sufficient information on bone height for preoperative implant planning in routine cases or when CBCT is unavailable. However, an additional CBCT evaluation might be helpful in cases where a safety margin cannot be respected due to insufficient bone height.

• Imaging Science in Dentistry
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• v.49 no.1
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• pp.45-51
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• 2019

Purpose: To determine the prevalence of concha bullosa (CB) and nasal septal deviation (NSD) and their impact on maxillary sinus volume (MSV). Materials and Methods: Cone-beam computed tomographic (CBCT) images of 106 Emirati people were used in this study. The direction and angle of septal deviation were calculated. The presence of CB, which could be unilateral, contralateral, or bilateral in relation to the direction of NSD, was also recorded. MSV was measured using reconstructed Digital Imaging and Communication in Medicine images on Dolphin 3D imaging software version 11.8 premium (Dolphin Imaging, Chatsworth, CA, USA). P values<0.05 were considered to indicate statistical significance. Results: CB was detected in 37.7% of the sample; 20.7% of the sample showed single unilateral CB and 16.6% had single bilateral CB. NSD was seen in 74.5% of the sample. In the participants with CB, 45.5% showed mild deviation, 34.4% showed moderate deviation, and only 12.5% showed severe septal deviation. CB, but not NSD, was associated with significantly higher MSV on the affected side (P=0.001). Conclusion: Although NSD was observed in more than two-thirds of the sample and CB was present in more than one-third of the sample, only CB had a significant impact on MSV.

• Imaging Science in Dentistry
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• v.49 no.1
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• pp.9-17
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• 2019

Purpose: This study aimed to introduce a novel method to evaluate the alveolar bone and interdental septum in the anterior mandible using cone-beam computed tomography (CBCT). Materials and Methods: Fifty-six CBCT scans from adult patients were selected. The CBCT scans were obtained before and after orthodontic treatment. The following measurements were taken: width of the alveolar bone and the interdental septum, height of the interdental septum, height of the bone plates, distance between the cementoenamel junction and marginal bone crests, and vertical positioning of the mandibular incisor, using the lingual plane as a reference. To test the reproducibility and the stability of the lingual plane, a triangle was traced in the anterior mandible. The intra-class correlation coefficient(ICC) was used to determine intra- and inter-examiner agreement. The paired Student t-test was used to evaluate the area of the triangle and the reproducibility of all measurements. Results: The ICC was excellent for the alveolar bone and dental measurements (0.9989 and 0.9977, respectively), as well as for the interdental septum (0.9987 and 0.9961, respectively). The area of the triangles showed stability in the lingual plane (P>0.05). For the alveolar bone, mandibular incisor, and interdental septum measurements, no statistically significant differences were found between the 2 examiners(P>0.05), confirming the technical reliability of the measurements. Conclusion: The method used in this study provides a valid and reproducible assessment of alveolar bone dimensions in the anterior mandible measured on CBCT images.

• The korean journal of orthodontics
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• v.49 no.1
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• pp.41-48
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• 2019

Objective: This in-vivo study aimed to compare landmark identification errors in anteroposterior (AP) and posteroanterior (PA) cephalograms generated from cone-beam computed tomography (CBCT) scan data in order to examine the feasibility of using AP cephalograms in clinical settings. Methods: AP and PA cephalograms were generated from CBCT scans obtained from 25 adults. Four experienced and four inexperienced examiners were selected depending on their experience levels in analyzing frontal cephalograms. They identified six cephalometric landmarks on AP and PA cephalograms. The errors incurred in positioning the cephalometric landmarks on the AP and PA cephalograms were calculated by using the straight-line distance and the horizontal and vertical components as parameters. Results: Comparison of the landmark identification errors in CBCT-generated frontal cephalograms revealed that landmark-dependent differences were greater than experienceor projection-dependent differences. Comparisons of landmark identification errors in the horizontal and vertical directions revealed larger errors in identification of the crista galli and anterior nasal spine in the vertical direction and the menton in the horizontal direction, in comparison with the other landmarks. Comparison of landmark identification errors between the AP and PA projections in CBCT-generated images revealed a slightly higher error rate in the AP projections, with no inter-examiner differences. Statistical testing of the differences in landmark identification errors between AP and PA cephalograms showed no statistically significant differences for all landmarks. Conclusions: The reproducibility of CBCT-generated AP cephalograms is comparable to that of PA cephalograms; therefore, AP cephalograms can be generated reliably from CBCT scan data in clinical settings.