Digital panoramic radiographs are useful for diagnosis of osteoporosis in Korean postmenopausal women.

OBJECTIVE: The purpose of this study was to determine whether digital panoramic radiographs could be used for the diagnosis of osteoporosis through evaluation of the radiographs based on the correlation with bone mineral density (BMD). METHODS: One hundred and ninety-four post-menopausal women were selected from participants who had participated in the Dong-gu study. Panoramic radiographic indices measured are mental index (MI), mandibular cortical index (MCI) and simple visual estimation (SVE). BMD at the lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry (DXA). The Pearson's correlation test was performed to analyse the correlation between MI and age and BMD at the lumbar spine, femoral neck and total hip. Multiple linear regression analysis was performed to analyse the association of MI, MCI and SVE with BMD after adjusting for age, height and weight. To determine the optimal cut-off point of MI for the diagnosis of osteoporosis, the receiver operating characteristic analysis was performed. RESULTS: The MI was positively correlated with BMDs: lumbar spine: r = 0.36, femoral neck: r = 0.59 and total hip: r = 0.58 (p < 0.001). As age increased, MI decreased (r = -0.46). BMD at the lumbar spine and total hip were significantly lower in participants with reduction of mandibular width, thinning and resorption of mandibular cortex by the MI, SVE and MCI, respectively. The optimal cut-off value of MI for the diagnosis of spinal osteoporosis was 2.22 mm. CONCLUSION: Thickness and morphological changes of mandibular inferior cortical bone are associated with BMD, independent of age, height and weight. These results suggest that MI, MCI and SVE may be useful indices for the diagnosis of osteoporosis in a Korean population.

Ameloblastoma with dystrophic calcification: A case report with 3-dimensional cone-beam computed tomographic images of calcification.

This report presents a rare case of ameloblastoma with histopathologic and radiographic calcification, including 3-dimensional cone-beam computed tomographic (CBCT) images. A 22-year-old woman had hard swelling on the right mandible. Panoramic and CBCT images showed multilocular radiolucencies with internal calcification foci in the right mandible. Three-dimensional images clearly showed varying-sized radiopacities within the lesion from various angles. A histopathologic examination showed central squamous differentiation and more densely packed peripheral palisading ameloblastic cells. Many areas of keratin pearls and calcifications were also seen. Four previous reports have described 5 cases of ameloblastoma showing histopathologic calcification. This might be the first report to present the calcification of ameloblastoma on panoramic and CBCT images, especially on 3-dimensional images.

Low serum 25-hydroxyvitamin D levels, tooth loss, and the prevalence of severe periodontitis in Koreans aged 50 years and older.

PURPOSE: Vitamin D deficiency may cause bone loss and increased inflammation, which are well-known symptoms of periodontal disease. This study investigated whether serum 25-hydroxyvitamin D (25(OH)D) levels are associated with periodontal disease status and tooth loss. METHODS: Cross-sectional data from 5,405 individuals aged ≥50 years (2,253 males and 3,152 females) were obtained from the 2008-2010 Dong-gu study, a prospective cohort study of risk factors for chronic diseases. Periodontal examinations were conducted to evaluate the number of remaining teeth, the periodontal probing depth (PPD), the clinical attachment level (CAL), and bleeding on probing. The percentages of sites with PPD ≥4 mm and CAL ≥4 mm were recorded for each participant. The severity of periodontitis was classified using the Centers for Disease Control and Prevention and the American Academy of Periodontology case definitions. Serum 25(OH)D levels were classified as reflecting severe deficiency, deficiency, insufficiency, or sufficiency. Multivariate linear regression analysis was performed to assess the associations of serum 25(OH)D levels with periodontal parameters and the number of remaining teeth after adjusting for confounders including age, smoking status, alcohol consumption status, month of blood collection, and physical activity. Multivariate logistic regression was used to evaluate the association between serum vitamin D levels and severe periodontitis. An overall statistical analysis and a stratified analysis by sex were performed. RESULTS: Overall, the rates of severe deficiency, deficiency, insufficiency, and sufficiency were 6.5%, 67.9%, 22.4%, and 3.2%, respectively. After adjustment for confounders, vitamin D levels were directly associated with the number of remaining teeth, an association that was significant in males, but not in females. Sufficient serum 25(OH)D was associated with a low frequency of severe periodontitis. CONCLUSIONS: This population-based cross-sectional study indicates that low serum 25(OH)D is significantly associated with tooth loss and severe periodontitis in Koreans aged 50 years and older.

Unexpected radiopaque foreign bodies encountered in dental practice.

OBJECTIVES: The purpose of the present study was to determine the presence of radiopaque foreign bodies on oral and maxillofacial radiographs and classify them. METHOD AND MATERIALS: The Study Comment section of the Picture Archiving and Communication System of Chonnam National University Dental Hospital was searched using 30 key words to identify images with radiopaque foreign bodies recorded between November 2008 and March 2017. A total of 503 cases of radiopaque foreign bodies were selected from among the recovered images. The radiopaque foreign bodies were sorted into 19 types, which were subsequently divided into two categories according to whether the foreign bodies were inserted intentionally or unintentionally. The two categories were subdivided into five groups based on the cause of insertion: Treatment, Esthetics, Cultural, Iatrogenesis, and Accident. RESULTS: In this study, the proportions of foreign bodies inserted intentionally (48%) and unintentionally (52%) were similar. When the foreign bodies were grouped based on the cause of insertion, the following frequencies were observed: Treatment, 41%; Esthetics, 7%; Cultural, <1%; Iatrogenesis, 51%; and Accident, 1%. CONCLUSION: For adequate case management and to avoid unnecessary embarrassment and misinterpretation of unexpected radiopacities, clinicians should be familiar with the various types of foreign bodies and should ensure that detailed patient medical/dental history is obtained.

Osteoporosis detection in panoramic radiographs using a deep convolutional neural network-based computer-assisted diagnosis system: a preliminary study.

OBJECTIVES: To evaluate the diagnostic performance of a deep convolutional neural network (DCNN)-based computer-assisted diagnosis (CAD) system in the detection of osteoporosis on panoramic radiographs, through a comparison with diagnoses made by oral and maxillofacial radiologists. METHODS: Oral and maxillofacial radiologists with >10 years of experience reviewed the panoramic radiographs of 1268 females {mean [± standard deviation (SD)] age: 52.5 ± 22.3 years} and made a diagnosis of osteoporosis when cortical erosion of the mandibular inferior cortex was observed. Among the females, 635 had no osteoporosis [mean (± SD) age: 32.8 ± SD 12.1 years] and 633 had osteoporosis (72.2 ± 8.5 years). All panoramic radiographs were analysed using three CAD systems, single-column DCNN (SC-DCNN), single-column with data augmentation DCNN (SC-DCNN Augment) and multicolumn DCNN (MC-DCNN). Among the radiographs, 200 panoramic radiographs [mean (± SD) patient age: 63.9 ± 10.7 years] were used for testing the performance of the DCNN in detecting osteoporosis in this study. The diagnostic performance of the DCNN-based CAD system was assessed by receiver operating characteristic (ROC) analysis. RESULTS: The area under the curve (AUC) values obtained using SC-DCNN, SC-DCNN (Augment) and MC-DCNN were 0.9763, 0.9991 and 0.9987, respectively. CONCLUSIONS: The DCNN-based CAD system showed high agreement with experienced oral and maxillofacial radiologists in detecting osteoporosis. A DCNN-based CAD system could provide information to dentists for the early detection of osteoporosis, and asymptomatic patients with osteoporosis can then be referred to the appropriate medical professionals.

Antibacterial activity of pyrrolidine dithiocarbamate.

Pyrrolidine dithiocarbamate (PDTC), an antioxidant with a metal-chelating activity, has been used widely to inhibit the expression of inflammatory genes in vitro and in vivo. This study investigated whether PDTC has an antimicrobial activity against various bacteria. The antibacterial activity of PDTC and other compounds was evaluated in vitro by the broth microdilution method against Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Staphylococcus aureus, and Escherichia coli. Bacterial growth was inhibited by PDTC, where a wide range of sensitivity was demonstrated among the tested bacteria. The antibacterial activity of PDTC was reduced by the addition of copper chloride; in contrast, it was enhanced considerably by zinc chloride. Two different zinc chelators, Ca-saturated EDTA (Ca-EDTA) and N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine, blocked the antibacterial activity of PDTC, whereas Zn-EDTA failed to reduce the activity of PDTC. These results demonstrate for the first time that PDTC possesses an antibacterial activity, for which zinc is required, and suggest that PDTC, possessing a dual anti-inflammatory and antibacterial activity, may be considered for topical use for inflammatory diseases of bacterial origin.

Radiographic features of lingual mandibular bone depression using dental cone beam computed tomography.

OBJECTIVES: To describe accurately the radiographic characteristics of lingual mandibular bone depression (LMBD) using CBCT images. METHODS: This study included 30 cases of LMBD with CBCT images from 29 patients. Age, sex, location, shape, size, and the relationships of the LMBDs to adjacent anatomical structures such as the mandibular inferior cortex and mandibular canal were recorded. The correlation between age and size was evaluated using Pearson's correlation coefficient. RESULTS: The average age of the patients was 57 years. LMBDs occurred primarily in males (93%), occurrence in the right (n = 14) and left (n = 16) mandibles was approximately equal. The shapes were ovoid, round, peanut, triangular, or rectangular on panoramic radiographs. The occurrences in the molar, distal to the molar, and ramus regions were 63.3, 33.3, and 3.3% respectively. The mean size on CBCT was 15.4 mm in length, 11.2 mm in height, and 6.4 mm in depth. The relationship to the mandibular canal was categorized as separated (48.2%), contacted (31%), or go-through (20.7%). The relationship to the mandibular inferior cortex was classified as separated (20.7%), contacted (27.6%), or resorbed (51.7%). The Pearson's correlation coefficient showed a positive correlation between age and depth (r = 0.38; p = 0.038). CONCLUSIONS: The typical features of a LMBD were ovoid, round or mutilobated radiolucent shape, well-defined sclerotic border, and position in the posterior area of the mandible between the mandibular canal and inferior mandibular cortex. The buccolingual depth of LMBD was deeper with increasing age.

Annealing characteristics of nanostructured Cu-Fe-P alloy processed by accumulative roll-bonding.

Annealing characteristics of a nanostructured copper alloy processed by accumulative roll-bonding (ARB) were studied. A nano-grained Cu-Fe-P alloy processed by 8 cycles of the ARB was annealed at various temperatures ranging from 100 to 400 degrees C for 0.6 ks. The sample still showed an ultrafine grained (UFG) structure up to 250 degrees C, however above 300 degrees C it began to replace by equiaxed and coarse grains due to an occurrence of the conventional static recrystallization. The hardness of the annealed copper decreased largely above 300 degrees C. These annealing characteristics of the UFG copper alloy were compared to those of a high purity copper.

A comparative study of the deviation of the menton on posteroanterior cephalograms and three-dimensional computed tomography.

PURPOSE: Facial asymmetry has been measured by the severity of deviation of the menton (Me) on posteroanterior (PA) cephalograms and three-dimensional (3D) computed tomography (CT). This study aimed to compare PA cephalograms and 3D CT regarding the severity of Me deviation and the direction of the Me. MATERIALS AND METHODS: PA cephalograms and 3D CT images of 35 patients who underwent orthognathic surgery (19 males and 16 females, with an average age of 22.1±3.3 years) were retrospectively reviewed in this study. By measuring the distance and direction of the Me from the midfacial reference line and the midsagittal plane in the cephalograms and 3D CT, respectively, the x-coordinates (x1 and x2) of the Me were obtained in each image. The difference between the x-coordinates was calculated and statistical analysis was performed to compare the severity of Me deviation and the direction of the Me in the two imaging modalities. RESULTS: A statistically significant difference in the severity of Me deviation was found between the two imaging modalities (Δx=2.45±2.03 mm, p<0.05) using the one-sample t-test. Statistically significant agreement was observed in the presence of deviation (k=0.64, p<0.05) and in the severity of Me deviation (k=0.27, p<0.05). A difference in the direction of the Me was detected in three patients (8.6%). The severity of the Me deviation was found to vary according to the imaging modality in 16 patients (45.7%). CONCLUSION: The measurement of Me deviation may be different between PA cephalograms and 3D CT in some patients.

The location of midfacial landmarks according to the method of establishing the midsagittal reference plane in three-dimensional computed tomography analysis of facial asymmetry.

PURPOSE: The purpose of this study was to evaluate the influence of methods of establishing the midsagittal reference plane (MRP) on the locations of midfacial landmarks in the three-dimensional computed tomography (CT) analysis of facial asymmetry. MATERIALS AND METHODS: A total of 24 patients (12 male and 12 female; mean age, 22.5 years; age range, 18.2-29.7 years) with facial asymmetry were included in this study. The MRP was established using two different methods on each patient's CT image. The x-coordinates of four midfacial landmarks (the menton, nasion, upper incisor, and lower incisor) were obtained by measuring the distance and direction of the landmarks from the MRP, and the two methods were compared statistically. The direction of deviation and the severity of asymmetry found using each method were also compared. RESULTS: The x-coordinates of the four anatomic landmarks all showed a statistically significant difference between the two methods of establishing the MRP. For the nasion and lower incisor, six patients (25.0%) showed a change in the direction of deviation. The severity of asymmetry also changed in 16 patients (66.7%). CONCLUSION: The results of this study suggest that the locations of midfacial landmarks change significantly according to the method used to establish the MRP.

Diagnostic reference levels for panoramic and lateral cephalometric radiography of Korean children.

Pediatric patients are considered to be more radiosensitive than adults; thus, radiation dose evaluations based on radiologic examinations are particularly important in this population. However, no national diagnostic reference levels (DRLs) are available for pediatric patients in the Republic of Korea. Therefore, the aim of this study was to determine the usage of panoramic and cephalometric radiography under the National Health Insurance (NHI) scheme and to investigate the current DRLs for child panoramic and lateral cephalometric radiography using dose area product (DAP). DAP values were obtained for standard child exposure settings used routinely by dentists. Analysis was performed on data obtained from 28 panoramic and 20 cephalometric x-ray units for the DAP investigation. DRLs for child panoramic and cephalometric radiography were found to be 95.9 mGy cm and 121.3 mGy cm, respectively. These DRLs are higher than those recommended in the UK and Germany, which indicates that further effort is required to reduce pediatric doses in the Republic of Korea.

Interobserver agreement on the diagnosis of carotid artery calcifications on panoramic radiographs.

PURPOSE: This study was performed to investigate the interobserver agreement on the detection of carotid artery calcifications on panoramic radiographs. MATERIALS AND METHODS: This study consisted of panoramic radiographs acquired from 634 male patients of the age of 50 years or older. Having excluded carotids of no diagnostic quality, 1008 carotids from the panoramic radiographs of the patients were interpreted by two oral and maxillofacial radiologists independently for the presence of carotid artery calcifications. Statistical analysis was used to calculate the interobserver agreement. RESULTS: Interobserver agreement was obtained for 932 carotids (92.4%). Inconsistent interpretation of 76 carotids (7.5%) between the two observers was found. Cohen's kappa value was 0.688 (p<0.001). CONCLUSION: The probability of a match between the two observers was substantially high.

Deviation of landmarks in accordance with methods of establishing reference planes in three-dimensional facial CT evaluation.

PURPOSE: This study aimed to investigate the deviation of landmarks from horizontal or midsagittal reference planes according to the methods of establishing reference planes. MATERIALS AND METHODS: Computed tomography (CT) scans of 18 patients who received orthodontic and orthognathic surgical treatment were reviewed. Each CT scan was reconstructed by three methods for establishing three orthogonal reference planes (namely, the horizontal, midsagittal, and coronal reference planes). The horizontal (bilateral porions and bilateral orbitales) and midsagittal (crista galli, nasion, prechiasmatic point, opisthion, and anterior nasal spine) landmarks were identified on each CT scan. Vertical deviation of the horizontal landmarks and horizontal deviation of the midsagittal landmarks were measured. RESULTS: The porion and orbitale, which were not involved in establishing the horizontal reference plane, were found to deviate vertically from the horizontal reference plane in the three methods. The midsagittal landmarks, which were not used for the midsagittal reference plane, deviated horizontally from the midsagittal reference plane in the three methods. CONCLUSION: In a three-dimensional facial analysis, the vertical and horizontal deviations of the landmarks from the horizontal and midsagittal reference planes could vary depending on the methods of establishing reference planes.

The correlation of carotid artery calcification on panoramic radiographs and determination of carotid artery atherosclerosis with ultrasonography.

OBJECTIVES: To investigate the association of carotid artery calcification (CAC) on panoramic radiographs and determine carotid artery atherosclerosis with ultrasonography. STUDY DESIGN: The study included 4050 subjects aged 50 years and older. Panoramic radiographs for the presence of CAC were interpreted. Common carotid artery intima-media thickness (CCA-IMT), carotid bulb IMT (CB-IMT), carotid plaques, and the diameter of the common carotid artery (CCA-diameter) were measured by using ultrasonography. RESULTS: CB-IMT was significantly greater in male subjects with CAC than in those without CAC. CCA-diameter was significantly greater in subjects with CAC than in those without CAC in both genders. However, there was no significant difference in CCA-IMT. CAC was associated with carotid plaque (for men, odds ratio [OR] 2.14; 95% confidence interval [CI] 1.01-3.36; for women, OR 1.19; 95% CI 0.84-1.67). CONCLUSION: CAC on panoramic radiographs was positively associated with IMT and plaque in men and positively associated with carotid diameter in both sexes. CAC on panoramic radiographs was positively associated with carotid atherosclerosis.

Use of spherical coordinates to evaluate three-dimensional facial changes after orthognathic surgery.

PURPOSE: This study aimed to assess the three-dimensional (3D) facial changes after orthognathic surgery by evaluating the spherical coordinates of facial lines using 3D computed tomography (CT). MATERIALS AND METHODS: A 19-year-old girl was diagnosed with class III malocclusion and facial asymmetry. Orthognathic surgery was performed after orthodontic treatment. Facial CT scans were taken before and after orthognathic surgery. The patient had a menton deviation of 12.72 mm before surgery and 0.83 mm after surgery. The spherical coordinates of four bilateral facial lines (ramal height, ramal lateral, ramal posterior and mandibular body) were estimated from CT scans before and after surgery on the deviated and opposite side. RESULTS: The spherical coordinates of all facial lines changed after orthognathic surgery. Moreover, the bilateral differences of all facial lines changed after surgery, and no bilateral differences were zero. CONCLUSION: The spherical coordinate system was useful to compare differences between the presurgical and postsurgical changes to facial lines.

A comparison study of different facial soft tissue analysis methods.

OBJECTIVES: The purpose of this study was to evaluate several different facial soft tissue measurement methods. MATERIALS AND METHODS: After marking 15 landmarks in the facial area of 12 mannequin heads of different sizes and shapes, facial soft tissue measurements were performed by the following 5 methods: Direct anthropometry, Digitizer, 3D CT, 3D scanner, and DI3D system. With these measurement methods, 10 measurement values representing the facial width, height, and depth were determined twice with a one week interval by one examiner. These data were analyzed with the SPSS program. RESULTS: The position created based on multi-dimensional scaling showed that direct anthropometry, 3D CT, digitizer, 3D scanner demonstrated relatively similar values, while the DI3D system showed slightly different values. All 5 methods demonstrated good accuracy and had a high coefficient of reliability (>0.92) and a low technical error (<0.9 mm). The measured value of the distance between the right and left medial canthus obtained by using the DI3D system was statistically significantly different from that obtained by using the digital caliper, digitizer and laser scanner (p < 0.05), but the other measured values were not significantly different. On evaluating the reproducibility of measurement methods, two measurement values (Ls-Li, G-Pg) obtained by using direct anthropometry, one measurement value (N'-Prn) obtained by using the digitizer, and four measurement values (EnRt-EnLt, AlaRt-AlaLt, ChRt-ChLt, Sn-Pg) obtained by using the DI3D system, were statistically significantly different. However, the mean measurement error in every measurement method was low (<0.7 mm). All measurement values obtained by using the 3D CT and 3D scanner did not show any statistically significant difference. CONCLUSION: The results of this study show that all 3D facial soft tissue analysis methods demonstrate favorable accuracy and reproducibility, and hence they can be used in clinical practice and research studies.

Normal range of facial asymmetry in spherical coordinates: a CBCT study.

PURPOSE: This study aimed to measure the bilateral differences of facial lines in spherical coordinates from faces within a normal range of asymmetry utilizing cone-beam computed tomography (CBCT). MATERIALS AND METHODS: CBCT scans from 22 females with normal symmetric-looking faces (mean age 24 years and 8 months) were selected for the study. The average menton deviation was 1.01±0.66 mm. The spherical coordinates, length, and midsagittal and coronal inclination angles of the ramal and mandibular lines were calculated from CBCT. The bilateral differences in the facial lines were determined. RESULTS: All of the study subjects had minimal bilateral differences of facial lines. The normal range of facial asymmetry of the ramal and mandibular lines was obtained in spherical coordinates. CONCLUSION: The normal range of facial asymmetry in the spherical coordinate system in this study should be useful as a reference for diagnosing facial asymmetry.

Diagnostic reference levels in intraoral dental radiography in Korea.

PURPOSE: The objectives of this study were to survey the radiographic exposure parameters, to measure the patient doses for intraoral dental radiography nationwide, and thus to establish the diagnostic reference levels (DRLs) in intraoral dental X-ray examination in Korea. MATERIALS AND METHODS: One hundred two intraoral dental radiographic machines from all regions of South Korea were selected for this study. Radiographic exposure parameters, size of hospital, type of image receptor system, installation duration of machine, and type of dental X-ray machine were documented. Patient entrance doses (PED) and dose-area products (DAP) were measured three times at the end of the exit cone of the X-ray unit with a DAP meter (DIAMENTOR M4-KDK, PTW, Freiburg, Germany) for adult mandibular molar intraoral dental radiography, and corrections were made for room temperature and pressure. Measured PED and DAP were averaged and compared according to the size of hospital, type of image receptor system, installation duration, and type of dental X-ray machine. RESULTS: The mean exposure parameters were 62.6 kVp, 7.9 mA, and 0.5 second for adult mandibular molar intraoral dental radiography. The mean patient dose was 2.11 mGy (PED) and 59.4 mGycm(2) (DAP) and the third quartile one 3.07 mGy (PED) and 87.4 mGycm(2) (DAP). Doses at university dental hospitals were lower than those at dental clinics (p<0.05). Doses of digital radiography (DR) type were lower than those of film-based type (p<0.05). CONCLUSION: We recommend 3.1 mGy (PED), 87.4 mGycm(2) (DAP) as the DRLs in adult mandibular molar intraoral dental radiography in Korea.

Adenomatoid odontogenic tumor associated with unerupted first primary molar.

Adenomatoid odontogenic tumors (AOTs) are an uncommon benign odontogenic tumor. Both central and peripheral forms occur. Radiographically, the central variants are comprised of a follicular type (those associated with the crown of an embedded tooth) and an extrafollicular type (those with no embedded tooth). A review of the literature showed that only 3 cases of an association between AOT and unerupted primary teeth have been published. The purpose of this paper was to report a rare case of adenomatoid odontogenic tumor associated with an unerupted primary first molar in a 7-year-old boy.

Application of spherical coordinate system to facial asymmetry analysis in mandibular prognathism patients.

PURPOSE: The purpose of this study was to compare asymmetric mandibular prognathism individuals with symmetric mandibular prognathism individuals using a new alternate spherical coordinate system. MATERIALS AND METHODS: This study consisted of 47 computed tomographic images of patients with mandibular prognathism. The patients were classified into symmetric and asymmetric groups. Mandibular and ramal lines were analyzed using an alternate spherical coordinate system. The length as well as midsagittal and coronal inclination angle of the lines was obtained. The bilateral differences of the spherical coordinates of the facial lines were statistically analyzed in the groups. RESULTS: There were significant differences between the groups in bilateral difference of the length and midsagittal inclination angle of the lines (p<0.05). The bilateral difference of the length and midsagittal inclination angle of the lines has significant correlation with chin deviation (p<0.05). CONCLUSION: The new alternate spherical coordinate system was able to effectively evaluate facial lines. The bilateral difference of lengths and midsagittal inclination of the facial lines might contribute to the facial asymmetry in mandibular prognathism individuals.