Prediction of Histological Grade of Oral Squamous Cell Carcinoma Using Machine Learning Models Applied to F-FDG-PET Radiomics.

The histological grade of oral squamous cell carcinoma affects the prognosis. In the present study, we performed a radiomics analysis to extract features from F-FDG PET image data, created machine learning models from the features, and verified the accuracy of the prediction of the histological grade of oral squamous cell carcinoma. The subjects were 191 patients in whom an F-FDG-PET examination was performed preoperatively and a histopathological grade was confirmed after surgery, and their tumor sizes were sufficient for a radiomics analysis.

Deep learning with convolution neural network detecting mesiodens on panoramic radiographs: comparing four models.

The aim of this study was to develop an optimal, simple, and lightweight deep learning convolutional neural network (CNN) model to detect the presence of mesiodens on panoramic radiographs. A total of 628 panoramic radiographs with and without mesiodens were used as training, validation, and test data. The training, validation, and test dataset were consisted of 218, 51, and 40 images with mesiodens and 203, 55, and 61 without mesiodens, respectively.

Masseter muscle cross-sectional area and late implant failure: A case-control study.

Introduction: Occlusal overload is considered to be one of the causes of late implant failure. However, it is unclear whether the magnitude of the patient's occlusal force is a risk factor for late implant failure.

Purpose: This case-control study aimed to clarify the association between the cross-sectional area (CSA) of the masseter muscle and late implant failure.

A three-dimensional investigation of mandibular deviation in patients with mandibular prognathism.

Background: Craniofacial disharmony in cases of jaw deformity associated with abnormal lateral deviation of the jaw mostly involves both the maxilla and mandible. However, it has been still difficult to capture the jaw deviation aspect in a 3-dimensional and quantitative techniques. In this study, we focused on 3-dimensional mandibular morphology and position of the condylar head in relation to the base of the skull in patients with mandibular prognathism, one of the most common jaw deformities.

Histogram analysis of F-FDG PET imaging SUVs may predict the histologic grade of oral squamous cell carcinoma.

Objective: We tested the hypothesis that histogram analysis parameters of standardized uptake values (SUVs) obtained preoperatively using F-fluorodeoxyglucose positron emission tomography (F-FDG PET) are significantly influenced by differences in metabolic capacity due to the histologic grade of oral squamous cell carcinoma (OSCC).

Study Design: The study included 62 patients who were clinically diagnosed with OSCC and received surgical treatment after an F-FDG PET examination. Histogram analysis was performed using all voxels contained in the tumor area of each patient with an SUV ≥2.

Quantitative evaluation of elasticity of lower orbicularis oris muscle during the lip closing measurement using sonographic elastography.

Background: Lip closing functions have never been evaluated from the viewpoint of elastic properties.

Objectives: The purpose of the present study was to investigate the behavior of the lower orbicularis oris muscle during a button-pull exercise to measure lip closing force and quantitatively evaluate its elastic properties using sonographic elastography.

Methods: Appropriate compression loads for elastography were randomly measured on one of three types of acoustic couplers on three examiners.

Evaluation of permanent and primary enamel and dentin mineral density using micro-computed tomography.

Objectives: The present study was performed to investigate the mineral density distribution in enamel and dentin for both permanent and primary teeth and to establish the standard density per tooth type using micro-computed tomography (CT).

Methods: Fifty-seven extracted human teeth (37 permanent, 20 primary) were evaluated in the present study. The enamel and dentin mineral densities in the extracted teeth were measured using micro-CT.

Clinical guidelines for dental cone-beam computed tomography.

Dental cone-beam computed tomography (CBCT) received regulatory approval in Japan in 2000 and has been widely used since being approved for coverage by the National Health Insurance system in 2012. This imaging technique allows dental practitioners to observe and diagnose lesions in the dental hard tissue in three dimensions (3D). When performing routine radiography, the examination must be justified, and optimal protection should be provided according to the ALARA (as low as reasonably achievable) principles laid down by the International Commission on Radiological Protection.

The relationship between masseter muscle pain and T2 values in temporomandibular joint disorders.

Objective: Myofascial pain in temporomandibular joint disorders (TMDs) is evoked by various factors, including edematous change. We investigated whether the pain pattern is related to edematous change by using T2 mapping generated by magnetic resonance imaging to detect water content in the tissue.

Study Design: One hundred and five patients diagnosed with TMDs, with or without unilateral masseter muscle pain, were divided into 6 groups according to their pain experience: pain on compression (23 cases), pain on movement (13 cases), spontaneous pain (4 cases), pain on compression and movement (14 cases), pain on compression and spontaneous pain (2 cases), and no pain (49 cases).

Nondestructive Microcomputed Tomography Evaluation of Mineral Density in Exfoliated Teeth with Hypophosphatasia.

Most cases of hypophosphatasia (HPP) exhibit early loss of primary teeth. Results of microcomputed tomography (micro-CT) analysis of teeth with HPP have rarely been reported. The purpose of the present study was to describe the mineral density distribution and mapping of exfoliated teeth from an HPP patient using micro-CT.

Finite element analysis of implant-embedded maxilla model from CT data: comparison with the conventional model.

Purpose: There are no entire maxillary finite element analysis models available, as a base of reference for the dimensions of conventional segment finite element analysis models. The objectives of this study were: (1) to construct a maxillary model derived from a human skull and to investigate the strain distribution around a posterior implant embedded in it; (2) to investigate the usability of conventional segment maxillary models.

Methods: CT DICOM data of a human dried skull maxilla was imported into the Mesh Generation Tools (ANSYS AI environment) and a computer-generated implant-abutment unit was bicortically embedded into it.

Comparison of altered signal intensity, position, and morphology of the TMJ disc in MR images corrected for variations in surface coil sensitivity.

Objective: The purpose of this study is to evaluate the corrections of signal intensity of the temporomandibular joint (TMJ) disc caused by variations in sensitivity of the magnetic resonance imaging (MRI) surface coil, to compare the modified signal intensities of the posterior and anterior bands, and then to evaluate the relationship of the signal intensity difference to altered disc position and morphology in a group of TMJ patients.

Study Design: MRI was performed on 96 joints. All patients underwent imaging in axial, coronal, and sagittal planes using fast-spin echo sequences (FSE).

Chronic hematic cyst of the temporomandibular joint.

Hematic cyst refers to accumulation of blood or blood breakdown products in a non epithelium-lined fibrous tissue capsule. Hepatic cyst is a term often used for deeply placed, incompletely resorbed hematoma hemorrhagic cyst, which may remain unchanged and unidentified for long periods of time. Trauma is the major causative factor, although it is often vague or totally uncalled by the patient.

CT and MR imaging features of oral and maxillofacial hemangioma and vascular malformation.

Purpose: To present CT and MR images and compare CT and MRI features of oral and maxillofacial hemangioma and vascular malformation.

Material And Methods: The clinical materials consisted of nine vascular tumors from nine patients examined by both CT and MR scanners between November 1996 and March 2002. Both CT and MR images were retrospectively evaluated.

MR of 2270 TMJs: prevalence of radiographic presence of otomastoiditis in temporomandibular joint disorders.

Objective: The purpose of this study is to determine the prevalence of radiographic presence of otomastoiditis while examining temporomandibular joint (TMJ) disorders in magnetic resonance images (MRI) in a series of 2270 temporomandibular joint magnetic resonance images and to examine the relationship between otomastoiditis and TMJ disorders.

Materials And Methods: 2270 temporomandibular joint magnetic resonance images and patients' data were retrospectively investigated. Magnetic resonance images were obtained from the patients who referred to Osaka University Dental Hospital Outpatient Clinic with TMJ complaints for the last four years (from January 1998 to January 2003).

MRI of nasoalveolar cyst: case report.

Nasoalveolar cyst is a rare nonodontogenic cyst arising in the nasoalar region of the face. In this case, a 39-year-old female had a nontender, fluctuant, soft, round, and bluish lesion in the right anterior gingiva of the right maxilla. Panoramic and magnetic resonance imaging examinatioins were performed.