Quantitative analysis of mandibular cortical morphology using artificial intelligence-based computer assisted diagnosis for panoramic radiography on underlying diseases and dental status in women over 20 years of age.

Background/purpose: Recently, an artificial intelligence-based computer-assisted diagnosis (AI-CAD) for panoramic radiography was developed to scan the inferior margin of the mandible and automatically evaluate mandibular cortical morphology. The aim of this study was to analyze quantitatively the mandibular cortical morphology using the AI-CAD, especially focusing on underlying diseases and dental status in women over 20 years of age. Materials and methods: 419 patients in women over 20 years of age who underwent panoramic radiography were included in this study. The mandibular cortical morphology was analyzed with an AI-CAD that evaluated the degree of deformation of the mandibular inferior cortex (MIC) and mandibular cortical index (MCI) automatically. Those were analyzed in relation to underlying diseases, such as diabetes, hypertension, dyslipidemia, rheumatism and osteoporosis, and dental status, such as the number of teeth present in the maxilla and mandible. Results: The degree of deformation of MIC in women under 51 years of age (21-50 years; n = 229, 16.0 ± 12.7) was significantly lower than those of over 50 years of age (51-90 years; n = 190, 45.1 ± 23.0), and the MCI was a significant difference for the different age group. Regarding the degree of deformation of MIC and MCI in women over 50 years of age, osteoporosis and number of total teeth present in the maxilla and mandible were significant differences. Conclusion: The results of this study indicated that the mandibular cortical morphology using the AI-CAD is significantly related to osteoporosis and dental status in women over 50 years of age.

A case of radicular cyst on deciduous tooth in a 7-year-old child.

Radicular cysts are the most common cystic lesions in the oral cavity, and have a rare occurrence in the primary dentition. We report a case of radicular cyst of mandible in child by multimodal imaging including panoramic radiography, CT, and MR imaging. A 7-year-old girl presented with swelling and without pain, and hypoesthesia on the right side of the mandible. On clinical examination, an expansive lesion with undulation was found to the buccal cortex of the right side of the mandible. Panoramic radiograph showed a unilocular radiolucency with well-defined margin, displaced tooth, and root resorption in the right mandible. Regarding CT imaging, axial soft tissue algorithm CT and bone tissue algorithm CT showed a low-attenuation internal structure and expansion of the buccal cortex of the right side of the mandible. Three-dimensional-CT showed expansion of the buccal cortex of the right side of the mandible. Multiplanar reformation imaging showed displaced tooth, root resorption, and expansion of the buccal cortex of the right side of the mandible. On T1-weighted image, the expansive lesion showed low signal intensity, and T2-weighted and STIR images revealed high signal intensity. A partial biopsy of the mandibular region was performed. Histopathological diagnosis was radicular cyst caused by apical periodontitis with abscess. This case suggests that multimodal imaging, especially CT and MR imaging, could be effective for evaluating mandibular lesions in child.

A case of odontogenic keratocyst in the buccal space: characterization by multimodality imaging including computed tomography, diffusion-weighted magnetic resonance imaging, and ultrasonography.

Odontogenic keratocyst (OKC) is a relatively common non-inflammatory jaw lesion. OKC is known to occur most often in the mandibular angle and mandibular ramus, but rarely outside the bone. In this report, we describe characteristic multimodality imaging of OKC in the buccal space, especially diffusion-weighted MR imaging (DWI) with apparent diffusion coefficient (ADC) mapping, extra-oral and intra-oral ultrasonography. On clinical examination, an approximately 20 mm in diameter mass with elastic hardness was found the left side of the buccal area. Contrast-enhanced CT showed areas of internal non-contrast lesions in the left buccal space. On T1-weighted image, the mass showed multilocular high signal intensity, and homogeneous internal. T2-weighted images revealed high signal at the marginal part and slightly median signal in the internal part. STIR images revealed a heterogeneous high signal in the interior. Furthermore, DWI and ADC map showed high signal and moderate-to-low signal intensity, respectively. ADC value of the lesion was 1.55 × 10-3 mm2 s-1. On extra-oral ultrasonography, the tumor showed clear boundary, hypoechoic, homogeneous internal architecture and vascular signals, and heterogeneous hard of the lesion. On intra-oral ultrasonography also showed clear boundary, hypoechoic, homogeneous internal architecture, heterogeneous hard of the tumor, and back echo enhance. The histopathologic diagnosis based on a full excisional specimen was odontogenic keratocyst. This case suggests that multimodality imaging, especially MR imaging with ADC and DWI, and extra and intra-oral ultrasonography with color Doppler imaging and elastography, could be effective for evaluating buccal lesions.

A pilot study of half-value layer measurements using a semiconductor dosimeter for intraoral radiography.

Purpose: This pilot study was conducted to evaluate half-value layer (HVL) measurements obtained using a semiconductor dosimeter for intraoral radiography. Materials and Methods: This study included 8 aluminum plates, 4 of which were low-purity (less than 99.9%) and 4 high-purity (greater than 99.9%). Intraoral radiography was performed using an intraoral X-ray unit in accordance with the dental protocol at the authors' affiliated hospital: tube voltage, 60 kVp and 70 kVp; tube current, 7 mA; and exposure time, 0.10 s. The accuracy of HVL measurements for intraoral radiography was assessed using a semiconductor dosimeter. A simple regression analysis was performed to compare the aluminum plate thickness and HVL in relation to the tube voltage (60 kVp and 70 kVp) and aluminum purity (low and high). Results: For the low-purity aluminum plates, the HVL at 60 kVp (Y) and 70 kVp (Y) was significantly correlated with the thickness of the aluminum plate (X), with Y = 1.708 + 0.415X (r=0.999, P<0.05) and Y = 1.980 + 0.484X (r=0.999, P<0.05), respectively. Similarly, for the high-purity aluminum plates, the HVL at 60 kVp (Y) and 70 kVp (Y) was significantly correlated with the plate thickness (X), with Y = 1.696 + 0.454X (r=0.999, P<0.05) and Y = 1.968 + 0.515X (r=0.998, P<0.05), respectively. Conclusion: This pilot study examined the relationship between aluminum plate thickness and HVL measurements using a semiconductor dosimeter for intraoral radiography. Semiconductor dosimeters may prove useful in HVL measurement for purposes such as quality assurance in dental X-ray imaging.

Maximum and mean standardized uptake values of medication-related osteonecrosis of the jaw with bone SPECT/CT: comparison of mandibular pathologies, control and temporomandibular joints.

OBJECTIVE: Recently, single-photon emission CT/CT (SPECT/CT) plays an important role in assessing patients with medication-related osteonecrosis of the jaw (MRONJ). The aim of this study was to investigate maximum and mean standardized uptake values (SUVs) of MRONJ with bone SPECT/CT, especially comparison of mandibular pathologies, control and temporomandibular joints. METHODS: 61 mandibular patients with MRONJ who underwent bone SPECT/CT were included in this study. The maximum and mean SUVs of the lesion, right and left sides of the lesion, opposite side of the lesion as control, right and left temporomandibular joints were analyzed using a workstation and software. The SUVs of MRONJ were analyzed using one-way analysis of variance with Tukey's honestly significant difference test. Patient characteristics with MRONJ and SUVs were analyzed using Mann-Whitney U test. P-values less than 0.05 were considered to indicate statistical significance. RESULTS: The maximum and mean SUVs for opposite side of the lesions (4.4 ± 2.0 and 1.8 ± 0.7) were significantly lower than those for mandibular lesions (18.3 ± 8.1 and 6.3 ± 2.8), right side of the lesions (8.1 ± 3.9 and 2.9 ± 1.3) and left side of the lesions (8.1 ± 3.9 and 2.8 ± 1.4), respectively. The maximum and mean SUVs for right and left sides of the lesions, and opposite side of the lesions, right and left temporomandibular joints were not significant difference. Furthermore, the maximum SUVs of the mandibular lesions were a significant difference for age and staging. CONCLUSIONS: The maximum and mean SUVs with SPECT/CT can be useful in the quantitative management of MRONJ patients.

Evaluation of the efficacy of diffusion-weighted magnetic resonance imaging and apparent diffusion coefficients in the diagnosis of maxillary diseases.

OBJECTIVE: We investigated the efficacy of using diffusion-weighted imaging (DWI) with quantitative apparent diffusion coefficient (ADC) mapping in the diagnosis of maxillary diseases. STUDY DESIGN: We evaluated 146 cases of maxillary diseases (32 malignant tumors, 11 benign tumors, 28 maxillary cysts, 60 cases of maxillary sinusitis, and 15 maxillary sinus retention cysts) that had been examined using magnetic resonance imaging. The DWI sequence was obtained with b values of 0 and 800 s/mm2 and ADC values were calculated. We used one-way analysis of variance and the Tukey honestly significant difference test to identify differences within and between the types of diseases. RESULTS: Mean ADC values for malignant tumors (1.07 × 10-3 mm2 s-1) were significantly lower than ADCs for benign tumors (1.85 × 10-3 mm2 s-1), maxillary cysts (1.77 × 10-3 mm2 s-1), maxillary sinusitis (2.34 × 10-3 mm2 s-1), and maxillary sinus retention cysts (2.52 × 10-3 mm2 s-1), with P < 0.001.   Mean ADC differed significantly between all disease types except between maxillary sinusitis and maxillary sinus retention cysts. ADC values also significantly differed between specific lesions within the malignant tumor and maxillary cyst groups. CONCLUSIONS: The use of ADC values can be useful in the differential diagnosis of malignant maxillary diseases, benign lesions, cysts, and inflammatory and reactive conditions.

Accuracy of non-contact semiconductor X-ray analyzer for quality assurance in intraoral radiography: a comparison with ionization chamber dosimeter.

OBJECTIVES: The aim of the present study was to evaluate the accuracy of a non-contact semiconductor X-ray analyzer for quality assurance in intraoral radiography, especially a comparison with an ionization chamber dosimeter. METHODS: Intraoral radiography was performed with intraoral X-ray unit using the dental protocol at our hospital: tube voltage, 70 kV; tube current, 7 mA. Accuracy of dose and half-value layer (HVL) measurements was analyzed with a non-contact semiconductor X-ray analyzer and an ionization chamber dosimeter. Stability of the semiconductor sensor, effect of scattered radiation, and comparison of measured HVL between the ionization chamber and the semiconductor sensor were analyzed in this study. RESULTS: The values with the semiconductor sensor were tube voltage: 70.3 ± 0.2 kVp (degree of variability: 0.28%), dose: 454.1 ± 12.3 µGy (degree of variability: 2.7%), and HVL: 1.91 ± 0.02 mmAl (degree of variability: 1.0%). With collimator, the dose with the semiconductor sensor and the ionization chamber decreased by 2.3 µ Gy and 5.2 µ Gy, respectively. The measured HVL of the semiconductor dosimeter was more than that of ionization chamber, and the semiconductor dosimeter was less than ionization chamber in variation of between without and with collimator. CONCLUSION: This study indicated the accuracy of a non-contact semiconductor X-ray analyzer for quality assurance in intraoral radiography, especially a comparison with an ionization chamber dosimeter. The semiconductor sensor can be useful for quality assurance in intraoral radiography.

Examination for the Factors Involving to Joint Effusion in Patients with Temporomandibular Disorders Using Magnetic Resonance Imaging.

BACKGROUND: This study investigated the factors involving joint effusion in patients with temporomandibular disorders. METHODS: The magnetic resonance images of 131 temporomandibular joints (TMJs) of patients with temporomandibular disorders were evaluated. Gender, age, disease classification, duration of manifestation, muscle pain, TMJ pain, jaw opening disturbance, disc displacement with and without reduction, deformation of the articular disc, deformation of bone, and joint effusion were investigated. Differences in the appearance of symptoms and observations were evaluated using cross-tabulation. The differences in the amounts of synovial fluid in joint effusion vs. duration of manifestation were analyzed using the Kruskal-Wallis test. Multiple logistic regression analysis was performed to analyze the factors contributing to joint effusion. RESULTS: Manifestation duration was significantly longer when joint effusion was not recognized (p < 0.05). Arthralgia and deformation of the articular disc were related to a high risk of joint effusion (p < 0.05). CONCLUSIONS: The results of this study suggest that joint effusion recognized in magnetic resonance imaging was easily observed when the manifestation duration was short, and arthralgia and deformation of the articular disc were related to a higher risk of joint effusion.

A computer program to assess the bone scan index for Tc-99m hydroxymethylene diphosphonate: evaluation of jaw pathologies of patients with bone metastases using SPECT/CT

PURPOSE: This study aimed to evaluate the jaw pathologies of patients with bone metastases using a computer program to assess the bone scan index (BSI) for Tc-99m hydroxymethylene diphosphonate (HMDP) with single-photon emission computed tomography/computed tomography (SPECT/CT). METHODS: Ninety-seven patients with jaw pathologies (24 with bone metastases and 73 without) were evaluated. High-risk hot spots and BSI in the patients were evaluated using the VSBONE BSI (ver.1.1) analysis software for Tc-99m HMDP that scanned SPECT/CT and automatically defined the data. The two groups were compared using the Pearson chi-square test and Mann-Whitney U test for high-risk hot spots and BSI, respectively. A P value of <0.05 was considered statistically significant. RESULTS: High-risk hot spot occurrence was significantly correlated to bone metastases [sensitivity, 21/24 (87.5%); specificity, 40/73 (54.8%); accuracy, 61/97 (62.9%); P < 0.001]. The number of high-risk hot spots was higher in patients with bone metastases (5.96 ± 10.30) than in those without (0.90 ± 1.50; P < 0.001). Furthermore, the BSI for patients with bone metastases (1.44 ± 2.18%) was significantly higher than for those without (0.22 ± 0.44%; P < 0.001). CONCLUSION: A computer program that assessed BSI for Tc-99m HMDP may be useful in the evaluation of patients with bone metastases using SPECT/CT.

Characteristic multimodal imaging of palatal follicular lymphoma: a case report on effectiveness of CT, diffusion-weighted MR imaging and intraoral ultrasonography.

Oral lymphomas are relatively uncommon. Follicular lymphoma is the second most common subtype of non-Hodgkin lymphoma. We report characteristic multimodal imaging of palatal follicular lymphoma, especially CT, diffusion-weighted MR imaging (DWI) and intraoral ultrasonography. A 67-year-old woman presented with swelling on the right side of the palate within 2 months. On clinical examination, an approximately 35 × 20 mm mass lesion with elastic soft was found to overlay the right side of the palate. Contrast-enhanced CT image showed a mass with homogeneous enhancement on the right side of the palate, and bone tissue algorithm CT showed focal erosion of the right posterior maxilla. Regarding MR imaging, on T1-weighted image, the mass showed low signal intensity and homogeneous enhancement, and T2-weighted and STIR images revealed intermediate and high signal intensity, respectively. Furthermore, DWI and apparent diffusion coefficient (ADC) map showed high and low signal intensity, respectively. ADC value of the mass was 0.60 × 10-3 mm2s-1. On intraoral ultrasonography, the mass showed clear boundary, hypoechoic echogenicity, homogeneous internal architecture, vascular signals using color Doppler imaging and heterogeneous hard using strain elastography. A partial biopsy of the palatal region was performed. Histopathological diagnosis was follicular lymphoma. This case suggests that multimodal imaging, especially CT, DWI with ADC map and intraoral ultrasonography with color Doppler imaging and strain elastography, could be effective for evaluating palatal lesions.

Study of clinical factors, focus score, lymphocyte type and NF-κB pathway in Sjögren's syndrome.

Sjögren's syndrome (SS) is an autoimmune disease that occurs predominantly in middle-aged and older women. Although focus score (FS) and lesion grade are determined at pathological diagnosis, few reports have examined whether these results reflect clinical symptoms. In this study, we examined and compared the results of comprehensive immunohistochemical staining of lymphocytes and NF-κB pathway in labial gland biopsies, clinical test data, and radionuclide imaging findings. One hundred labial gland biopsy specimens obtained from 20 female patients with primary SS (5 specimens per patient) were studied. Hematoxylin-eosin-stained specimens were reviewed and FS were calculated. Immunohistochemical staining of CD4, CD8, CD20, CD25, Foxp3, NF-κB, TNFAIP3 and IκBα was performed, and the results were compared with anti-SS-A/Ro (SS-A), anti-SS-B/La (SS-B) and antinuclear antibodies (ANA), and salivary gland scintigraphy findings. FS were significantly higher in the SS-A-, SS-B- and ANA-positive groups than in the respective -negative groups (p < 0.05). Of eight SS-A-positive and SS-B-negative cases, mean FS was 1.9 (seven cases: FS ≥ 1.0) and six cases were ANA-positive. In four SS-A-positive and SS-B-positive cases, mean FS was 3.2 (all cases: FS ≥ 1.0) and all cases were ANA-positive. In immunohistochemical staining, CD4-positive T cells tended to be more abundant than CD8-positive T cells. Small numbers of Foxp3-positive cells were found in all cases. NF-κB, TNFAIP3 and IκBα were positive in the acini, ductal epithelium, and lymphocytes in all cases. The above findings indicated a relationship between FS and clinical test data, and the association of NF-κB pathway with the pathophysiology of primary SS.

Comparison of maximum and mean standardized uptake values of jaw pathologies with bone SPECT/CT: an especial focus on medication-related osteonecrosis of the jaw.

OBJECTIVES: To investigate the comparison of maximum and mean standardized uptake values (SUVs) of jaw pathologies with bone Single-photon emission computed tomography/computed tomography (SPECT/CT), and a special focus on medication-related osteonecrosis of the jaw (MRONJ). METHODS: Eighty-nine patients with jaw pathologies (63 MRONJ, 13 chronic osteomyelitis, 11 osteoradionecrosis and 2 primary intraosseous carcinoma) underwent bone SPECT/CT scans acquisition at 4 h after intravenous injection of Tc-99m hydroxymethylene diphosphonate in this prospective study. The evaluation of mean and maximum SUVs of jaw pathologies were performed using Q. Metrix and Xeleris workstation and defined the data automatically. Statistical analyses were performed by Pearson's correlation coefficient for comparison of maximum and mean SUVs and Mann-Whitney U-test for SUVs of MRONJ. A P value lower than 0.05 was considered to indicate statistical significance. RESULTS: Maximum SUVs of MRONJ, chronic osteomyelitis, osteoradionecrosis and primary intraosseous carcinoma were 17.6 ± 8.4, 21.7 ± 7.1, 11.9 ± 4.8 and 26.6 ± 7.0, respectively. Mean SUVs of MRONJ, chronic osteomyelitis, osteoradionecrosis and primary intraosseous carcinoma were 10.1 ± 4.9, 11.9 ± 3.3, 7.0 ± 2.8 and 10.1 ± 4.5, respectively. The maximum SUV of jaw pathologies was significantly correlated with the mean SUV (Y = 0.494X + 1.228; R2 = 0.786; P < 0.001). Furthermore, maximum and mean SUVs of MRONJ had significant differences in underlying diseases, medication and staging. CONCLUSION: The maximum and mean SUVs with bone SPECT/CT can be an effective tool for the quantitative evaluation of jaw pathologies, especially MRONJ.

Comparison of single photon emission computed tomography-computed tomography, computed tomography and magnetic resonance imaging of osteonecrosis of jaw by new calculated parameters.

BACKGROUND: This study aimed to investigate parameters for medication-related osteonecrosis of jaw (MRONJ) patients using the bone SPECT/CT, especially bone mineral-based parameters. METHODS: Sixty-three patients with MRONJ (43 osteoporosis and 20 bone metastasises) underwent CT, MRI and SPECT/CT. A commercially available software automatically detected lesion area and calculated the quantitative SPECT/CT parameters as bone mineral-based standardized uptake value (SUV). RESULTS: Regarding stage of MRONJ patients, bone mineral based maximum SUV of stage 3 was significantly higher than stage 1, 2 (P = 0.018). Regarding duration of medication therapy, bone mineral based maximum SUV 1 year or more was significantly higher than less than 1 year P = 0.019). Regarding present of periosteal bone proliferation on CT, bone mineral based maximum SUV was significantly higher than those of absent (P = 0.029). Regarding spread of soft tissue inflammation on MRI, bone mineral based maximum SUV of 2 or more was significantly higher than those of less than 2 spaces (P = 0.025). Regarding blood pool phase imaging with SPECT, bone mineral based maximum SUV of intense uptake was significantly higher than those of decrease uptake (P = 0.002). CONCLUSIONS: SPECT/CT bone mineral-based parameters indicated significant difference in staging, dosing period, periosteal bone proliferation on CT, spread of soft tissue inflammation on MRI, and blood phase imaging with SPECT. Bone SPECT/CT bone mineral-based parameters are helpful for the assessment of MRONJ.

Volumetric analysis of mandibular lesions with SPECT/CT: a pilot clinical study of maximum standardized uptake value.

Purpose: This study was designed to investigate mandibular lesions using volumetric analysis with bone single-photon emission computed tomography/computed tomography (SPECT/CT). Material and methods: Eight patients with mandibular lesions underwent SPECT/CT scan acquisition 4 hours after injection of Tc-99m hydroxymethylene diphosphonate (HMDP). Regarding volumetric analysis, maximum standar-dized uptake value (SUV) was obtained using software and a workstation (Q.Volumetrix MI and GEniE-Xeleris 4 DR, respectively). The localization and size of the volume of interest (VOI) can be drawn over the lesion, mesial, distal, and opposite side as normal using the CT, SPECT, and SPECT/CT transaxials, coronals, and sagittals as the anatomical reference. Q.Volumetrix MI can analyse SUV of lesions by organ segmentation using optional pan and zoom imaging. Then, the dosimetry software provided multiple quantitative data for a given VOI. Statistical analyses for the maximum SUV were performed by Mann-Whitney U test. A p-value lower than 0.05 was considered as statistically significant. Results: Maximum SUVs for medication-related osteonecrosis of the jaw (n = 4, 25.4 ± 4.9), chronic osteomyelitis (n = 3, 14.6 ± 3.1), and squamous cell carcinoma (n = 1, 31.7) were significantly higher than those of the opposite side as normal mandible (3.8 ± 0.7, 4.6 ± 1.8, and 7.4, respectively; p = 0.000). Conclusions: Volumetric analysis with SPECT/CT could be useful for the evaluation of mandibular lesions, such as detecting and surgical planning.

AI-based computer-aided diagnosis for panoramic radiographs: Quantitative analysis of mandibular cortical morphology in relation to age and gender.

OBJECTIVE: This study aimed to investigate AI-based computer-aided diagnosis (AI-CAD) for panoramic radiographs, especially quantitative evaluation of mandibular cortical morphology in relation to age and gender. METHODS: 321 patients with jaw lesions who underwent panoramic radiography were prospectively included. The mandibular cortical morphology was analyzed with an AI-CAD that evaluated the degree of deformation of mandibular inferior cortex and mandibular cortical index (MCI) automatically. Those were analyzed in relation to age and gender, such as younger (≦ 20 years), middle (21-60 years) and older group (≧ 61 years) in men and women. RESULTS: The degree of deformation in older men (33.0 ± 18.5) was higher than those of middle (25.0 ± 15.3, p = 0.030) and younger (32.5 ± 16.9, p = 0.993), and those in older women (46.2 ± 22.5) was higher than those of middle (19.4 ± 16.5, p < 0.001) and younger (22.4 ± 14.5, p < 0.001). The MCI of women was a significant difference for aging (p < 0.001), although those of men was not significant difference for aging (p = 0.189). CONCLUSION: The AI-CAD could be a useful tool for the quantitative analysis of mandibular cortical morphology.

Odontogenic Infection Pathway to the Parapharyngeal Space: CT Imaging Assessment.

Introduction: Parapharyngeal space infection may lead to severe and potentially life-threatening complications. The aim of this study was to assess the odontogenic infection pathway to the parapharyngeal space using CT imaging. Materials and Methods: Nineteen patients in mandibular odontogenic infections with abscess who underwent contrast-enhanced CT were evaluated in this study. We reviewed the location of abscess and spread of odontogenic infections to the different components of the buccal space, submandibular space, sublingual space, masticator space and parapharyngeal space using CT imaging. The location of abscess and spread of odontogenic infections were analyzed with the Pearson Chi-square test. Results: Regarding the odontogenic infection pathway to parapharyngeal space, the masticator space (100%) was the most frequent, followed by the buccal space (85.7%), submandibular space (85.7%) and sublingual space (57.1%), while those without parapharyngeal space, the submandibular space (83.3%) was the most frequent, followed by the buccal space (75.0%), masticator space (58.3%) and sublingual space (33.3%). The masticator space was significant space in patients with/without parapharyngeal space infection (P = 0.047). Conclusion: CT imaging could be an effective method in assessment of odontogenic infection pathway to the parapharyngeal space. The odontogenic infection in masticator space tends to display spread of parapharyngeal space.

Diagnosis of Vertical Root Fractures in Endodontically Treated Teeth by Cone-Beam Computed Tomography.

The purpose of this study was to investigate the characteristics and the detection ability of vertical root fractures in endodontically treated teeth by intraoral radiography and cone-beam computed tomography (CBCT). CBCT images of 50 patients with root fractures in endodontically treated teeth were reviewed, and 36 vertical root fractures were taken in this study. The cause of fracture, core construction, kind of teeth, and fracture direction (bucco-lingual and mesio-distal fractures) were investigated. Detection ability of vertical root fractures by intraoral radiography and CBCT was also examined. Statistical analyses concerning the characteristics were performed by χ2 test, and the detection ability was analyzed by cross-tabulation. All of the fractured teeth were nontraumatized teeth. The vertical root fracture occurrence was not differed by core construction. The vertical root fracture number was largest at the premolar teeth (p = 0.005), and the number of the bucco-lingual fracture was larger than the mesio-distal fracture (p = 0.046). Vertical root fractures were detectable using CBCT, while undetectable by intraoral radiography (p < 0.001). Vertical root fractures occurred easily in premolar teeth with bucco-lingual direction, and CBCT is an adequate radiographic method to diagnose vertical root fracture.

Maximum standardized uptake value of normal structures in the head and neck with bone SPECT/CT.

INTRODUCTION: The quantitative parameter was successfully derived from the quantitative bone SPECT/CT images. The aim of this study was to evaluate maximum standardized uptake value (SUV) of normal structures in the head and neck with bone SPECT/CT. METHODS: Fifty-three patients with jaw lesions (11 chronic osteomyelitis, eight osteoradionecrosis and 34 medication-related osteonecrosis of the jaw) who had bone SPECT/CT were prospectively included. The maximum SUV of normal structures including vertebrae, sternal body, parietal bone and hyoid bone were analysed. Statistical analyses for the maximum SUV were performed by Pearson's rank correlation test. A P value lower than 0.05 was considered statistically significant. RESULTS: The maximum SUVs of vertebrae, sternal body, parietal bone and hyoid bone of all patients were 8.10 ± 3.72, 5.16 ± 2.05, 3.67 ± 1.55 and 1.44 ± 0.56, respectively. Furthermore, the maximum SUV of vertebrae was significantly correlated with that of sternal body (Y = 0.527X + 5.388 (R2 = 0.084, P = 0.035)). CONCLUSIONS: Maximum SUV with bone SPECT/CT should be useful for characterization of normal structures in the head and neck. Furthermore, the data reported herein can be used for reference in future studies and in clinical settings for head and neck lesions.

Nanoscale cutting using self-excited microcantilever.

The application of self-excitation is proposed to improve the efficiency of the nanoscale cutting procedure based on use of a microcantilever in atomic force microscopy. The microcantilever shape is redesigned so that it can be used to produce vibration amplitudes with sufficient magnitudes to enable the excitation force applied by an actuator to be transferred efficiently to the tip of the microcantilever for the cutting process. A diamond abrasive that is set on the tip is also fabricated using a focused ion beam technique to improve the cutting effect. The natural frequency of the microcantilever is modulated based on the pressing load. Under conventional external excitation conditions, to maintain the microcantilever in its resonant state, it is necessary to vary the excitation frequency in accordance with the modulation. In this study, rather than using external excitation, the self-excitation cutting method is proposed to overcome this difficulty. The self-excited oscillation is produced by appropriate setting of the phase difference between the deflection signal of the microcantilever and the feedback signal for the actuator. In addition, it is demonstrated experimentally that the change in the phase difference enables us to control the amplitude of the self-excitation. As a result, control of the cutting depth is achieved via changes in the phase difference.

Medication-related osteonecrosis of the jaw in a patient with multiple myeloma: an unusual case with tumor in the surgical specimen.

Multiple myeloma is characterized by a neoplastic proliferation of plasma cells primarily in the bone marrow. Neoplastic plasma cells stimulated osteoclasts, and destroy bone tissue, causing bone pain, pathological fractures, paralysis due to spinal cord compression, and hypercalcemia. Bisphosphonates are used as supportive therapy in the management of multiple myeloma. Medication-related osteonecrosis of the jaw (MRONJ) is a well-known complication of treatment with bisphosphonates, denosumab, and other drugs, such as anti-angiogenic agents and novel anti-cancer drugs. We report MRONJ in a patient with multiple myeloma, especially an unusual case with tumor in the surgical specimen. A 73-year-old woman presented with pain on the left side of the mandible within 3 months. On clinical examination, an exposed bone without purulent drainage presented on the left side of the mandible. Before 2 years, she received chemotherapy of zoledronate for multiple myeloma at another hospital. Panoramic imaging showed radiopacities of bone in the left side of the mandibular molar area. Multidetector computed tomography (MDCT) with axial, multiplanar reformation (MPR) and three-dimensional (3D) images showed the sequestrum without periosteal reaction. She was diagnosed as MRONJ, and underwent surgery. Finally, the surgical specimen was diagnosed as multiple myeloma in the sequestrum. This case suggests that the evaluation of the surgical specimen of MRONJ could be essential for detection of primary tumor.