• Imaging Science in Dentistry
• /
• v.40 no.2
• /
• pp.63-68
• /
• 2010

Purpose : To compare the CT numbers on 3 cone-beam CT (CBCT) images with those on multi-detector CT (MDCT) image using CT phantom and to develop linear regressive equations using CT numbers to material density for all the CT scanner each. Materials and Methods : Mini CT phantom comprised of five 1 inch thick cylindrical models with 1.125 inches diameter of materials with different densities (polyethylene, polystyrene, plastic water, nylon and acrylic) was used. It was scanned in 3 CBCTs (i-CAT, Alphard VEGA, Implagraphy SC) and 1 MDCT (Somatom Emotion). The images were saved as DICOM format and CT numbers were measured using OnDemand 3D. CT numbers obtained from CBCTs and MDCT images were compared and linear regression analysis was performed for the density, $\rho$ ($g/cm^3$), as the dependent variable in terms of the CT numbers obtained from CBCTs and MDCT images. Results : CT numbers on i-CAT and Implagraphy CBCT images were smaller than those on Somatom Emotion MDCT image (p<0.05). Linear relationship on a range of materials used for this study were $\rho$=0.001H+1.07 with $R^2$ value of 0.999 for Somatom Emotion, $\rho$=0.002H+1.09 with $R^2$ value of 0.991 for Alphard VEGA, $\rho$=0.001H+1.43 with $R^2$ value of 0.980 for i-CAT and $\rho$=0.001H+1.30 with $R^2$ value of 0.975 for Implagraphy. Conclusion: CT numbers on i-CAT and Implagraphy CBCT images were not same as those on Somatom Emotion MDCT image. The linear regressive equations to determine the density from the CT numbers with very high correlation coefficient were obtained on three CBCT and MDCT scan.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.31 no.2
• /
• pp.158-166
• /
• 2009

The application of CT with basis on 3 dimensional-reconstruction is getting more widely practiced. With the data obtained from cone-beam computed tomography(CBCT), not only the diagnosis of the patient with skeletal abnormality but also the virtual simulation of the orthognathic surgery were performed and its application would be popular in orthodontic field. We reported a case, a 19-year old man who was diagnosed mandibular prognathism and required orthognatic surgery. In this case, the virtual orthognathic surgery was simulated and surgical wafer was fabricated by using CBCT data. That wafer was applied the actual orthognathic surgery. After preoperative orthodontic treatment, we prepared surgery as follows. : (l)Acquisition of 3D image data, (2)Reconstruction of 3-dimensional virtual model, (3)Virtual model surgery, (4)Extraction of stere-olithographic image, (5)Check-up for occlusal interference, (6)Fabrication of surgical stent by stereolithography. Bilateral sagittal split ramus osteotomy was operated and used stereolithographic surgical stent. 1 month later, we superimposed CBCT datas of virtual surgery and that of actual surgery, and then compared the result. CT data's application for othognathic surgery yielded satisfactory outcomes.

• Imaging Science in Dentistry
• /
• v.47 no.3
• /
• pp.199-207
• /
• 2017

Purpose: Evaluation of alveolar bone is important in the diagnosis of dental diseases. The periodontal ligament space is difficult to clearly depict in cone-beam computed tomography images because the reconstruction filter conditions during image processing cause image blurring, resulting in decreased spatial resolution. We examined different reconstruction filters to assess their ability to improve spatial resolution and allow for a clearer visualization of the periodontal ligament space. Materials and Methods: Cone-beam computed tomography projections of 2 skull phantoms were reconstructed using 6 reconstruction conditions and then compared using the Thurstone paired comparison method. Physical evaluations, including the modulation transfer function and the Wiener spectrum, as well as an assessment of space visibility, were undertaken using experimental phantoms. Results: Image reconstruction using a modified Shepp-Logan filter resulted in better sensory, physical, and quantitative evaluations. The reconstruction conditions substantially improved the spatial resolution and visualization of the periodontal ligament space. The difference in sensitivity was obtained by altering the reconstruction filter. Conclusion: Modifying the characteristics of a reconstruction filter can generate significant improvement in assessments of the periodontal ligament space. A high-frequency enhancement filter improves the visualization of thin structures and will be useful when accurate assessment of the periodontal ligament space is necessary.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.31 no.2
• /
• pp.104-111
• /
• 2015

Purpose: The aim of this retrospective study was to investigate the prevalence rate and types of C-shaped roots and C-shaped canal in maxillary molars by analyzing cone-beam computed tomography (CBCT) in a Korean population. Materials and Methods: Total of 357 CBCT images of maxillary molars (186 first molar, 171 second molar) were evaluated by two Endodontic specialists. Results: Eight types of C-shaped roots and 5 types of C-shaped canals were founded, the prevalence rate of C-shaped roots and canals were 21.0% and 5.3% respectively. Conclusion: These anatomical variations were more frequent in second molars than the first molars. Clinicians should have anatomical knowledge about various types of C-shaped root and root canal for successful root canal therapy.

• Imaging Science in Dentistry
• /
• v.49 no.1
• /
• pp.59-63
• /
• 2019

Purpose: This study evaluated the prevalence and characteristics of maxillary antroliths using cone-beam computed tomography (CBCT) scans performed for maxillofacial diagnostic purposes. Materials and Methods: CBCT scans of 13,946 patients over the age of 20 were reviewed for maxillary antroliths, and prevalence according to sex, age, and the side of the jaw was calculated. The relationships of single or multiple antroliths with sex, side, and the degree of sinus inflammation were evaluated. The shape and dimension of antroliths were also assessed. The data were analyzed using descriptive statistics, the chi-square or Fisher exact tests, and Kendall's tau-b. Results: A total of 138 (0.99%) of the 13,946 patients showed an antrolith in at least 1 sinus. Only 18 patients presented a bilateral manifestation, which brought the total number of sinuses containing an antrolith to 156 (0.56%). Multiple antroliths were observed in 36 sinuses, and the total number of antroliths was 207: 110 punctate, 65 linear, and 32 amorphous. The antrolith dimensions varied from $1mm^2$ to $91mm^2$ (average, $10.2{\pm}15.5mm^2$). No statistically significant differences were found according to sex, side, and age group (P>0.05). However, there was a statistically significant difference between the multiplicity of antrolith and the degree of sinus inflammation (P<0.05). Conclusion: Cone-beam computed tomography is an effective modality for the detection of incidental antroliths. Maxillary antroliths were found to be very rare and were usually asymptomatic. Dentists should have a comprehensive understanding of their diagnosis and treatment in light of possible associated dental problems.

• Imaging Science in Dentistry
• /
• v.52 no.1
• /
• pp.1-9
• /
• 2022

Purpose: This systematic review aimed to compare assessments of the healing of periapical endodontic surgery using conventional radiography and cone-beam computed tomography (CBCT). Materials and Methods: This review of clinical studies was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. All articles published from 1990 to March 2020 pertaining to clinical and radiographic healing assessments after endodontic surgery using conventional radiography and CBCT were included. The question was "healing assessment of endodontic surgery using cone-beam computed tomography." The review was conducted by manual searching, as well as undertaking a review of electronic literature databases, including PubMed and Scopus. The studies included compared radiographic and CBCT assessments of periapical healing after periapical endodontic surgery. Results: The initial search retrieved 372 articles. The titles and abstracts of these articles were read, leading to the selection of 73 articles for full-text analysis. After the eligibility criteria were applied, 11 articles were selected for data extraction and qualitative analysis. The majority of studies found that CBCT enabled better assessments of healing than conventional radiography, suggesting higher efficacy of CBCT for correct diagnosis and treatment planning. A risk of bias assessment was done for 10 studies, which fell into the low to moderate risk categories. Conclusion: Three-dimensional radiography provides an overall better assessment of healing, which is imperative for correct diagnosis and treatment planning.

• The korean journal of orthodontics
• /
• v.53 no.4
• /
• pp.264-275
• /
• 2023

Objective: To investigate the effects of maxillary orthodontic expansion on the alveolar bone tissue in adult patients treated with aligners by using cone-beam computed tomography. Methods: Thirty patients (22 females and 8 males; mean age: 36.3 years) were treated with Invisalign^® aligners. Cone-beam computed tomography and digital models were obtained before (T0) and after (T1) upper arch expansion. The bone thicknesses in the cervical, middle, and apical areas of the incisors, canines, premolar, and first molars were buccally and palatally measured, totaling 96 areas and 2,880 measurements. The buccolingual inclinations and transverse measurements of the teeth were obtained from digital models to correlate them with the bone changes. The statistical tests used were Student's t-test, analysis of variance, and Pearson's correlation tests (p < 0.05). Results: From the 96 areas evaluated, 84 revealed an increase or stability in the alveolar bone thickness and twelve displayed significant bone loss. Bone changes did not correlate with the tooth inclination and transverse measurements. Conclusions: Within the limitation of the present study, mild levels of upper arch expansion obtained with Invisalign^® aligners in adult patients did not result in any clinically significant loss of alveolar bone thickness.

• Imaging Science in Dentistry
• /
• v.53 no.4
• /
• pp.345-353
• /
• 2023

Purpose: The objective of this study was to propose a method for developing a clinical phantom to reproduce various diseases that are clinically prevalent in the field of dentistry. This could facilitate diverse clinical research without unnecessarily exposing patients to radiation. Materials and Methods: This study utilized a single dry skull, which was visually and radiographically examined to evaluate its condition. Existing lesions on the dry skull were preserved, and other relevant lesions were artificially created as necessary. These lesions were then documented using intraoral radiography and cone-beam computed tomography. Once all pre-existing and reproduced lesions were confirmed by the consensus of 2 oral and maxillofacial radiologists, the skull was embedded in a soft tissue substitute. To validate the process, cone-beam computed tomography scans and panoramic radiographs were obtained of the fabricated phantom. All acquired images were subsequently evaluated. Results: Most lesions could be identified on panoramic radiographs, although some sialoliths and cracked teeth were confirmed only through cone-beam computed tomographic images. A small gap was observed between the epoxy resin and the bone structures. However, 2 oral and maxillofacial radiologists agreed that this space did not meaningfully impact the interpretation process. Conclusion: The newly developed phantom has potential for use as a standardized phantom within the dental field. It may be utilized for a variety of imaging studies, not only for optimization purposes, but also for addressing other experimental issues related to both 2- and 3-dimensional diagnostic radiography.

• Imaging Science in Dentistry
• /
• v.54 no.1
• /
• pp.71-80
• /
• 2024

Purpose: This study aimed to evaluate age-stratified radiographic features in temporomandibular joint osteoarthritis using cone-beam computed tomography. Materials and Methods: In total, 210 joints from 183 patients(144 females, 39 males, ranging from 12 to 88 years old with a mean age of 44.75±19.97 years) diagnosed with temporomandibular joint osteoarthritis were stratified by age. Mandibular condyle position and bony changes (flattening, erosion, osteophytes, subchondral sclerosis, and subchondral pseudocysts in both the condyle and articular eminence, thickening of the glenoid fossa, joint space narrowing, and joint loose bodies) were evaluated through cone-beam computed tomography. After adjusting for sex, the association between age groups and radiographic findings was analyzed using both a multiple regression model and a multinomial logistic regression model(α=0.05). Results: The prevalence of joint space narrowing and protruded condyle position in the glenoid fossa significantly increased with age (P<0.05). The risks of bony changes, including osteophytes and subchondral pseudocysts in the condyle; flattening, erosion, osteophyte, and subchondral sclerosis in the articular eminence; joint loose bodies; and thickening of the glenoid fossa, also significantly rose with increasing age (P<0.05). The number of radiographic findings increased with age; in particular, the increase was more pronounced in the temporal bone than in the mandibular condyle (P<0.05). Conclusion: Increasing age was associated with a higher frequency and greater diversity of bony changes in the temporal bone, as well as a protruded condyle position in the glenoid fossa, resulting in noticeable joint space narrowing in temporomandibular joint osteoarthritis.

• Restorative Dentistry and Endodontics
• /
• v.44 no.2
• /
• pp.16.1-16.12
• /
• 2019

Objectives: The upper molars generally have three roots; therefore, different combinations of fusion can occur, increasing the possibility of finding more complex root canal systems. The purpose of this study was to evaluate the prevalence and characterization of fused roots in first and second maxillary molars using cone-beam computed tomography (CBCT) in a Colombian population. Materials and Methods: A total of 1274 teeth were evaluated, of which 534 were maxillary first molars and 740 were maxillary second molars. Axial sections were made at the cervical, middle, and apical levels to determine the prevalence of root fusion and the types of fusion. Results: Overall, 43% of the molars (n = 551) presented some type of fused root. Root fusion was present in 23.4% of the maxillary first molars. The most frequent type of fused root was type 3 (distobuccal-palatal; DB-P) (58.9%). Root fusion was observed in 57.6% of the maxillary second molars, and the most prevalent type of fused root was type 6 (cone-shaped) (45.2%). Of the maxillary molars, 12.5% were classified as C-shaped. Conclusion: Within the limitations of this study, there was a high prevalence of fused roots in maxillary molars in the Colombian population, mainly in the maxillary second molars. In first molars, the most common type of fused root was type 3 (DB-P) and in second molars, the most common type was type 6 (cone-shaped). Additionally, molars with root fusion presented variation at different levels of the radicular portion, with implications for treatment quality.