• Imaging Science in Dentistry
• /
• 제46권2호
• /
• pp.87-92
• /
• 2016

Purpose: The aim of this study was to assess and compare the diagnostic performance of panoramic and occlusal radiographs in detecting submandibular sialoliths. Materials and Methods: A total of 40 patients (20 cases and 20 controls) were included in this retrospective study. Cases were defined as subjects with a submandibular sialolith confirmed by computed tomography (CT), whereas controls did not have any submandibular calcifications. Three observers with different expertise levels assessed panoramic and occlusal radiographs of all subjects for the presence of sialoliths. Intraobserver and interobserver agreement were assessed using the kappa test. Sensitivity, specificity, accuracy, positive and negative predictive values, and the diagnostic odds ratio of panoramic and occlusal radiographs in screening for submandibular sialoliths were calculated for each observer. Results: The sensitivity and specificity values for occlusal and panoramic radiographs all ranged from 80% to 100%. The lowest values of sensitivity and specificity observed among the observers were 82.6% and 80%, respectively (P=0.001). Intraobserver and interobserver agreement were higher for occlusal radiographs than for panoramic radiographs, although panoramic radiographs demonstrated a higher overall accuracy. Conclusion: Both panoramic and occlusal radiographic techniques displayed satisfactory diagnostic performance and should be considered before using a CT scan to detect submandibular sialoliths.

• Imaging Science in Dentistry
• /
• 제37권2호
• /
• pp.87-92
• /
• 2007

Purpose: To measure the absorbed doses of cone beam computed tomography (CBCT), which is recently being more frequently used, and to compare them with those of panoramic radiography. Materials and Methods: To measure the absorbed doses of CBCT ($PSR-9000N^{TM}$, Asahi Roentgen Ind. Co., Japan), we placed TLD chips on the skin regions above the parotid and thyroid glands, and on the dorsum of tongue in a dental head phantom. We used two image acquisition modes of the Dental and Panoramic modes of CBCT, which differed in the field of view. Also, panoramic radiographs (Auto IIIN, Asahi Roentgen Ind. Co., Japan) were taken to compare with the absorbed doses of CBCT. Result: In the Dental mode of CBCT, the absorbed doses of the parotid gland, dorsum of tongue, and thyroid gland were 3.53, 3.13, and 0.36 mGy, respectively. In the Panoramic mode of CBCT, they were 9.57, 9.15, and 0.85 mGy, respectively. The panoramic mode showed higher absorbed doses than those of the Dental mode. In the panoramic radiography, the absorbed doses of the parotid gland, dorsum of tongue, and thyroid gland were 1.21, 1.19, and 0.16 mGy, respectively. And they were about 1/3 of the Dental mode and 1/9 of the Panoramic mode of CBCT. Conclusion: Absorbed doses of CBCT are higher than those of panoramic radiography, and dependent upon the field of view.

• Imaging Science in Dentistry
• /
• 제52권1호
• /
• pp.33-41
• /
• 2022

Purpose: This study aimed to evaluate the structural complexity of craniofacial trabecular bone in multiple myeloma by fractal analysis of panoramic and lateral skull radiography, and to compare the fractal dimension values of healthy patients (HPs), pre-treatment patients (PTPs), and patients during bisphosphonate treatment (DTPs). Materials and Methods: Pairs of digital panoramic and lateral skull radiographs of 84 PTPs and 72 DTPs were selected. After application of exclusion criteria, 43 panoramic and 84 lateral skull radiographs of PTPs, 56 panoramic and 72 lateral skull radiographs of DTPs, and 99 panoramic radiographs of age- and sex-matched HPs were selected. The fractal dimension values from panoramic radiographs were compared among HPs, PTPs, and DTPs and between anatomical locations within patient groups using analysis of variance with the Tukey test. Fractal dimension values from lateral skull radiographs were compared between PTPs and DTPs using the Student t-test. Pearson correlation coefficients were used to assess the relationship between the mandible from panoramic radiographs and the skull from lateral skull radiographs. Intra-examiner agreement was assessed using intraclass correlation coefficients (α=0.05). Results: The fractal dimension values were not significantly different among HPs, PTPs, and DTPs on panoramic radiographs or between PTPs and DTPs on lateral skull radiographs (P>0.05). The mandibular body presented the highest fractal dimension values (P≤0.05). The fractal dimension values of the mandible and skull in PTPs and DTPs were not correlated. Conclusion: Fractal analysis was not sensitive for distinguishing craniofacial trabecular bone complexity in multiple myeloma patients using panoramic and lateral skull radiography.

• Imaging Science in Dentistry
• /
• 제30권1호
• /
• pp.16-22
• /
• 2000

Purpose : To evaluate the bone densities measured on copper-equivalent image of cross sectional view of mandibular edentulous premolar area obtained by multifuctional panoramic x-ray machine, PM 2002 CC with transversal slicing system. Materials and Methods: Panoramic cross sectional views with 8 mm focal layer of aluminum step and blocks, of hydroxyapatite (RA) step, 6 HA blocks and copper step wedge having 0.03 mm thickness of each step, and of 3 bone blocks cutted by 8 mm thickness mesiodistally and a dry mandible with copper step wedge were taken by using transversal slicing system in PM 2002 Cc. All reference-equivalent images were made and analyzed by NIH image program. Results: The average copper-equivalent value of cancellous bone of bone blocks on the panoramic cross sectional view was 0.026 ± 0.020 mm Cu. The calculated average bone density was 0.38g/cm². There was no significant difference (P>0.1) between the bone densities on intraoral digital view and on the panoramic digital cross sectional view. Conclusion: The copper-equivalent image of panoramic digital cross sectional view obtained by PM 2002 CC with very thin copper step wedge was supposed to be useful to measure the bone density of cancellous bone of mandible at the premolar edentulous area.

• Imaging Science in Dentistry
• /
• 제37권1호
• /
• pp.9-14
• /
• 2007

Purpose : To determine the more valuable information to detect the mandibular canal and the mental foramen in panoramic radiographs of a selected Korean population for the implant. Materials and Methods : This study analysed 288 panoramic radiographic images of patients taken at the Dental hospital of Chosun University retrospectively. Indirect digital panoramic X-ray machine (ProlineXC, PLANMECA, Finland) with processing by using Directview $CR950^@$ (Kodak, U.S.A.) and Direct digital panoramic X-ray machine (Promax, PLANMECA, Finland) were used for all exposures. All images were converted into Dicom format. Results : The common position of the mental foramen was in line with the longitudinal axis of the second premolar (68.1%). The mental foramen was symmetrical in 81.8% of cases. The mandibular canal was not identified at anterior portion and discontinued with the mental foramen in 27.8% of all cases, in 42.4% identified with lower border line continued with the mental foramen, in 14.6% with both upper and lower border lines, and in 15.3% unilaterally identified with lower border line. Conclusion : Clinicians can estimate the upper border line of the mandibular canal from the confirmation of the mental foramen and the lower border line of the mandibular canal symmetrically on the panoramic radiography taken in adjusted midsaggital plane of patient's head.

• Imaging Science in Dentistry
• /
• 제38권3호
• /
• pp.147-151
• /
• 2008

Purpose : The purpose of this study was to investigate whether fractal analysis of periapical and panoramic radiographs was useful in predicting osteoporosis risk. Materials and Methods : 37 postmenoposal women between the age of 42 and 79 were classified as normal and osteoporosis group according to the bone mineral density of lumbar vertebrae and periapical and panoramic radio-graphs were taken. Fractal dimensions at periapical areas of mandibular first molars were calculated to differentiate the two groups. Results : The mean fractal dimensions of normal group on periapical and panoramic radiographs were $1.413{\pm}0.079$, $1.517{\pm}0.071$ each. The mean fractal dimensions of osteoporotic group on periapical and panoramic radiographs were $1.498{\pm}0.086$, $1.388{\pm}0.083$ each. The mean fractal dimension from peripaical radiographs of osteoporotic group was statistically significantly higher than that of normal group. The mean fractal dimension from panoramic radiographs of osteoporotic group was statistically significantly lower than that of normal group. Conclusion : Fractal analysis using periapical and panoramic radiographs was useful in predicting osteoporosis.

• 대한디지털의료영상학회논문지
• /
• 제13권2호
• /
• pp.91-97
• /
• 2011

This study was conducted to know usefulness of panoramic radiography by comparing clinical evaluation and dental panoramic radiography in case of oral examination. Following results were concluded by analyzing difference between the result of Clinical evaluation and dental panoramic radiography. According to comparison the result of clinical evaluation and panoramic radiography, In Shin's research, dental caries was higher by 23.1%, periodontal disease was 31.9%, in An's research, dental caries was 24.2%. From new point of view from panoramic radiography, impacted tooth was 33.6%, Sinus abnormalities was 11.6%, periapical lesion was 5.4% in Shin's research and periapical lesion was 17.4%, 3rd molar impaction was 15.3% and retained root was 5.3% in An's research. Any kind of caries were not found in oral examination in the 66.7% of patients among patients with dental root caries in An's research. There were misdiagnose in oral examination(even side(59.5%),proximal side(59.5%), seconds caries(44.0%).

• Imaging Science in Dentistry
• /
• 제39권2호
• /
• pp.69-73
• /
• 2009

Purpose: This study compared panoramic radiography and cone beam computed tomography (CBCT) for evaluating the relationship between the maxillary sinus floor and the roots of maxillary molars. Materials and Methods: Paired panoramic radiographs and CBCT images from 97 subjects were analysed. This analysis classified 388 maxillary molars according to their relationship to the maxillary sinus floor on panoramic radiograph and CBCT. Correlations between these two radiographic techniques were examined. Results: Maxillary molar roots that were separate from the sinus floor showed the same classification in 100% of the cases when using these two imaging techniques. The corresponding percentage for such roots that were in contact with the sinus floor was 75%. When roots overlapped the maxillary sinus floor on panoramic radiographs, only 26.4% of maxillary first molars and 60.0% of second molars showed protrusion of roots into the sinus with CBCT. Conclusion : The results of the study suggest that roots projecting into the sinus on panoramic radiographs require a three-dimensional image in order to analyze the proximity of their apex to the sinus floor. (Korean J Oral Maxillofac Radiol2009; 39 : 69-73)

• Imaging Science in Dentistry
• /
• 제52권3호
• /
• pp.275-281
• /
• 2022

Purpose: The aim of this study was to assess the performance of a deep learning system for permanent tooth germ detection on pediatric panoramic radiographs. Materials and Methods: In total, 4518 anonymized panoramic radiographs of children between 5 and 13 years of age were collected. YOLOv4, a convolutional neural network (CNN)-based object detection model, was used to automatically detect permanent tooth germs. Panoramic images of children processed in LabelImg were trained and tested in the YOLOv4 algorithm. True-positive, false-positive, and false-negative rates were calculated. A confusion matrix was used to evaluate the performance of the model. Results: The YOLOv4 model, which detected permanent tooth germs on pediatric panoramic radiographs, provided an average precision value of 94.16% and an F1 value of 0.90, indicating a high level of significance. The average YOLOv4 inference time was 90 ms. Conclusion: The detection of permanent tooth germs on pediatric panoramic X-rays using a deep learning-based approach may facilitate the early diagnosis of tooth deficiency or supernumerary teeth and help dental practitioners find more accurate treatment options while saving time and effort

• 대한치과교정학회지
• /
• 제41권4호
• /
• pp.255-267
• /
• 2011

본 연구에서는 cone beam computed tomography (CBCT)를 이용한 삼차원 영상을 기준으로 CBCT-재구성 파노라마영상 형성 시의 신뢰성을 입증하고 CBCT 삼차원 영상과 비교하여 실제 근원심 치축을 가장 잘 나타낼 수 있는 이차원 파노라마영상을 찾고자 하였다. 연구 모형은 두부계측방사선사진의 평균치에 따라 제작되었고 CBCT와 파노라마방사선영상 촬영을 위해 촬영 시마다 연구 모형이 반복적으로 재위치되었다. 파노라마방사선영상은 $-5^{\circ}$, $0^{\circ}$, $+5^{\circ}$로 연구 모형의 교합평면을 변화시키면서 촬영되었다. 이후 CBCT 삼차원 영상과 CBCT-재구성 파노라마영상 및 파노라마방사선영상에서 측정된 계측값을 평가하였다. CBCT 삼차원 영상과 CBCT-재구성 파노라마영상의 전치 및 견치부에서 통계학적으로 유의성 있는 차이를 나타내지 않았으나 대부분의 소구치부에서는 통계학적으로 유의성 있는 차이를 나타내었다. 그리고 CBCT-재구성 파노라마영상과 파노라마방사선영상은 대부분의 치아에서 통계학적으로 유의성 있는 차이를 나타내었다. CBCT-재구성 파노라마영상이 근원심 치축 평가 시 임상적으로 사용 가능함을 보여주었다.