Towards Optimum Mandibular Reconstruction for Dental Occlusal Rehabilitation: From Preoperative Virtual Surgery to Autogenous Particulate Cancellous Bone and Marrow Graft with Custom-Made Titanium Mesh-A Retrospective Study.

The purpose of this retrospective study was to evaluate computer-assisted virtual surgery and the outcomes of mandibular reconstruction using an autogenous particulate cancellous bone and marrow (PCBM) graft combined with a custom-made titanium mesh (TiMesh) using a three-dimensional (3D) printing model. Eighteen consecutive patients were included, and preoperative virtual simulation surgery was performed using digital data. Segmental bone defects showed deviation of the mandible due to displacement of the condyle and segments, unnatural length of the mandibular body, or poorer intermaxillary relationship compared to the marginal bone defect caused by previous operations. These mandibular disharmonies could be simulated, and virtual surgery was performed on a computer with adjustment of displaced mandibular segments, length of the mandibular body, and dental arch with digital bone augmentation. TiMesh was manually pre-bent using a 3D printing model, and PCBM from the iliac crest was grafted with TiMesh. The short-term clinical results were good; reconstruction of the alveolar crest was prosthetically desirable; and minor complications were observed. In conclusion, virtual reconstruction is crucial for treating complex deviated mandibles. Accurate condylar and dental arch positions with an optimum mandibular length are important for prosthetically satisfactory mandibular reconstruction.

Intramuscular Myxoma of the Intrinsic Muscles of the Tongue: A Case Report with Literature Review.

Myxoma is a benign tumor of mesenchymal origin. It frequently occurs in the muscles of the hip and extremities; however, it rarely occurs in the head and neck region. This report describes the second case of an intramuscular myxoma of the tongue. A 23-year-old woman was referred to our institution for the diagnosis and treatment of a left tongue lesion. T2-weighted magnetic resonance imaging revealed an 8 × 6-mm mass in the tongue. Based on a clinical diagnosis of a tongue tumor, excisional biopsy was performed under general anesthesia. The histopathological diagnosis was an intramuscular myxoma. The postoperative course was uneventful, and there was no evidence of tumor recurrence 3 years after surgery.

Diagnostic Accuracy of High-Grade Intraepithelial Papillary Capillary Loops by Narrow Band Imaging for Early Detection of Oral Malignancy: A Cross-Sectional Clinicopathological Imaging Study.

This study aimed to clarify the advantages and disadvantages of conventional visual inspection (CVI), endoscopic white light imaging (WLI), and narrow-band imaging (NBI) and to examine the diagnostic accuracy of intraepithelial papillary capillary loops (IPCL) for the detection of oral squamous cell carcinoma (OSCC). This cross-sectional study included 60 participants with oral mucosal diseases suspected of having oral potentially malignant disorders (OPMDs) or OSCC. The patients underwent CVI, WLI, NBI, and incisional biopsy. Images were evaluated to assess the lesion size, color, texture, and IPCL. Oral lichen planus (OLP) and oral leukoplakia lesions were observed in larger areas with NBI than with WLI; 75.0% were associated with low-grade (Type 0-II) IPCL. Various types of oral leukoplakia were seen; however, all OSCC cases showed high-grade (Type III-IV) IPCL. The diagnostic accuracy of high-grade IPCL for OSCC showed a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 100%, 80.9%, 59.1%, 100%, and 85.0%, respectively. A non-homogeneous lesion with high-grade IPCL strongly suggested malignancy. Overall, our results indicate that WLI and NBI are powerful tools for detecting precancerous and cancerous lesions using IPCL. However, NBI is influenced by mucosal thickness; therefore, image interpretation is important for accurate diagnosis.

Osteosarcoma of the Mandible in an Elderly Patient.

Osteosarcoma is a malignant tumor in which the cancerous cells produce an osteoid matrix or mineralized bone. Jaw bones are affected in 6% of all osteosarcomas and are the fourth most common site of origin. Surgical treatment of osteosarcoma in elderly patients is rarely reported. Here, we report successful treatment of osteosarcoma arising in the mandible of a 90-year-old man. The patient was referred to our institution for diagnosis and treatment of an oral lesion. Intraoral examination revealed that a hard mass measuring 35 × 27 mm was located on the floor of the oral cavity, attached to the bone, and its growth displaced the tongue posteriorly. Therefore, he experienced difficulty in speech and swallowing. Biopsy of the mandibular mass was suspicious for chondrosarcoma. Preoperative examination did not detect critical risks for general anesthesia or surgery. Based on a clinical diagnosis of a malignant bone tumor of the mandible, segmental mandibular resection with reconstruction using a titanium plate was performed. Surgical site infection occurred on postoperative day 12, which was resolved by drainage, local irrigation, and administration of antibiotics. There was no delirium or cardiovascular or pulmonary complications. Surgery resolved the patient's difficulties in speech and swallowing. There was no evidence of tumor recurrence or metastasis 4 years after surgery. This case showed that it was not necessary to exclude surgical treatment merely because the patient was 90 years old. Indications for surgery should be determined individually to improve the patient's quality of life.

Tophaceous pseudogout of the temporomandibular joint extending into the cranium: a case report with literature review.

Pseudogout is a disease characterized by calcium pyrophosphate crystal deposition. Involvement of the temporomandibular joint (TMJ) is rare. We herein report a case of tophaceous pseudogout of the TMJ with cranial extension. An 83-year-old woman was referred to our institution for treatment of right TMJ pain. The patient's medical and family histories were unremarkable. Magnetic resonance imaging showed a mass of about 35 mm in diameter compressing the bottom of the right temporal lobe of the brain. Based on a clinical diagnosis of a right TMJ tumour, biopsy was performed under general anaesthesia. The histopathological diagnosis was pseudogout. Considering the risk of surgically induced brain damage, the patient's advanced age and her relatively good quality of life, the treatment plan simply involved the observation of the lesion. Fourteen months after biopsy, the patient's activities of daily living remained unchanged and she had no TMJ pain.

Custom-Made Titanium Mesh Tray for Mandibular Reconstruction Using an Electron Beam Melting System.

Mandibular reconstruction using a titanium mesh tray and autologous bone is a common procedure in oral and maxillofacial surgery. However, there can be material problems-such as broken titanium mesh trays-which may undermine long-term functionality. This study was designed to investigate the optimal conditions for a titanium mesh tray with an ideal mandibular shape and sufficient strength, using computer-aided design, computer-aided manufacturing technology, and electron beam additive manufacturing. Specimens were prepared using Ti-6Al-4V extra low interstitial titanium alloy powder and an electron beam melting (EBM) system. The mechanical strength of the plate-shaped specimens was examined for differences in the stretch direction with respect to the stacking direction and the presence or absence of surface treatment. While evaluating the mechanical strength of the tray-shaped specimens, the topology was optimized and specimens with a honeycomb structure were also verified. Excellent mechanical strength was observed under the condition that the specimen was stretched vertically in the stacking direction and the surface was treated. The results of the tray-shaped specimens indicated that the thickness was 1.2 mm, the weight reduction rate was 20%, and the addition of a honeycomb structure could withstand an assumed bite force of 2000 N. This study suggests that the EBM system could be a useful technique for preparing custom-made titanium mesh trays of sufficient strength for mandibular reconstruction by arranging various manufacturing conditions.

Clinical Diagnostic Imaging Study of Osteoradionecrosis of the Jaw: A Retrospective Study.

Radiation therapy (RT) plays a significant role in the management of head and neck malignancies. This study aimed to review the clinical symptoms and various imaging findings of osteoradionecrosis (ORN) and provide a clinical perspective on the development of ORN. The retrospective cohort was composed of 57 sites in 54 patients who had a history of RT and suspected ORN and 48 sites in 45 patients who were confirmed to have ORN. Image analyses included computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET)/CT, bone scintigraphy, and single-photon emission CT (SPECT). The irradiated tissue was damaged by RT, and the extent of damage was correlated with clinical symptoms. The bone marrow showed sclerotic changes and the devitalized bone showed bone resorption after invasive stimulation. Chronic trismus and pathological fracture are considered severe conditions, typically occurring in the last stage of ORN. Furthermore, neurological symptoms were an important sign of tumor recurrence, since diagnostic imaging was difficult. The possible treatment options vary depending on the stage of ORN. We speculate that bone sclerosis reactions and bone resorption are sequential reactions that seem to be protective measures of the bone to radiation injury.

Overview of Radiological Studies on Visualization of Gubernaculum Tracts of Permanent Teeth.

The eruption pathway from the dental follicle to the gingiva for permanent teeth is known as the gubernaculum tract (GT), a physiologic structure thought to play a role in tooth eruption. Cone beam computed tomography and multi-detector computed tomography have recently been used to visualize the GT, with the results indicating that this structure might be related to the normal eruption of teeth. By contrast, curved and/or constricted GTs may lead to abnormal tooth eruption. In addition, complex odontomas have been reported from within the GT or dental sac of unerupted permanent teeth. If an odontoma occurs within the GT, the tooth will not erupt normally. Moreover, the imaging characteristics of the GT from the top of the odontogenic mass to the alveolar crest are extremely useful for making a differential pathological diagnosis and for differentiating between odontogenic and non-odontogenic masses. Therefore, radiological studies on the GT have been attracting increasing attention. Given this background, the present review aims to clarify the imaging characteristics and review recent studies on the GT considering the importance of the research.

Primary epithelioid angiosarcoma originating from the mandibular gingiva: a case report of an extremely rare oral lesion.

BACKGROUND: Angiosarcoma occurs very rarely in the oral cavity, and the epithelioid type is even rarer. Here, we report a rare case involving an elderly man with a primary epithelioid angiosarcoma that originated from the mandibular gingiva and resembled a dentigerous cyst on radiographs. CASE PRESENTATION: A 66-year-old Japanese man visited our hospital with a chief complaint of gingival swelling in right mandibular third molar region. A panoramic radiograph showed bone resorption around the crown of right mandibular third molar, which was impacted. Incisional biopsy confirmed a diagnosis of epithelioid angiosarcoma. The lesion exhibited aggressive proliferation after biopsy resulting in uncontrolled bleeding and difficulty in closing the mouth. Mandibular segmental resection including the tumor was performed without reconstruction. Because of the aggressive preoperative course of the tumor, the patient received adjuvant chemotherapy. There were no signs of recurrence during a 2-year follow-up period. CONCLUSIONS: A review of the literature yielded only four reported cases of epithelioid angiosarcoma in the jaw region, with the lesions occurring in the maxilla in three cases. To our knowledge, this is the second case of primary epithelioid angiosarcoma in the mandible.

Radiation Esophagitis in a Patient with Oral Carcinoma and Bone Metastasis.

Radiation esophagitis requiring endoscopic evaluation occurs quite rarely, affecting <1% of patients undergoing radiation treatment. Acute radiation esophagitis develops within 3 weeks of radiation therapy. We describe herein a case of radiation esophagitis in a patient with oral carcinoma with multiple general bone metastases. Cisplatin, fluorouracil, and cetuximab were given for 3 cycles. Radiation therapy (30 Gy) to the thoracic vertebrae and lumbar vertebrae was prescribed to prevent worsening of bone metastases and relieve pain. Neutropenia was also observed due to chemotherapy. After the end of radiation therapy, the patient experienced chest pain, heartburn, and dysphagia. Upper gastrointestinal endoscopy revealed severe radiation esophagitis of endoscopic Fukui Acute Radiation Esophagitis grade 4. Oral food was discontinued and an intravenous proton-pump inhibitor was administered. After 3 weeks, upper gastrointestinal endoscopy showed improvement of radiation esophagitis, with scars. The symptoms of chest pain, heartburn, and dysphagia had also disappeared. This is the first case to be reported of acute radiation esophagitis in a patient with oral carcinoma with bone metastasis who experienced dramatic improvement of endoscopic findings. Neutropenia appears to be associated with more severe acute radiation esophagitis.

Cystadenoma of the tongue: report of a case with long-term follow-up.

Cystadenoma is a rare benign salivary gland neoplasm characterized by a predominantly multicystic growth pattern. The parotid gland is involved in about 45-50% of cystadenoma cases, with the minor glands of the lip and buccal mucosa being the next most common sites. The tongue is rarely involved; only one congenital case is reported in the literature. Here, we report a 63-year-old man who was referred to our hospital for a nodule on the right edge of his tongue that developed into an elastic soft mass, 4 mm in diameter. It was clinically diagnosed as a benign tumour and removed under local anaesthesia. Microscopically, the lesion was composed of multiple cysts of various sizes and shapes, with or without papillary intraluminal short projections. It was diagnosed as cystadenoma. The postoperative course was uneventful, and we found no evidence of recurrence at the postoperative 14-year follow-up.

Real-time evaluation of swallowing in patients with oral cancers by using cine-magnetic resonance imaging based on T2-weighted sequences.

OBJECTIVE: The aim of this study was to evaluate whether a new cine-magnetic resonance imaging (CMRI) technique might be useful for evaluating swallowing function in patients with different types of oral cancers by assessing 12 CMRI-related parameters. STUDY DESIGN: In total, 111 patients with oral cancers were evaluated. We examined whether visualization of fluid flow and determination of flow direction to the trachea or the esophagus were possible with CMRI. We evaluated the correlations between CMRI-related parameters and self-reported dysphagia scores as the status of dysphagia, T classification groups as tumor staging for preoperative patients, alterations in CMRI-related parameters between pre- and postoperative patients, and the degree of invasiveness of oral cancer surgery. RESULTS: We could judge the flow direction to the esophagus on CMRI in all 111 patients. Six CMRI-related parameters showed significant correlations with dysphagia status. Increases in CMRI-related parameters were significantly related to deterioration of swallowing status, as shown by a decrease in self-reported dysphagia scores, advances in the T classification, and degree of invasiveness of oral cancer surgery. CONCLUSIONS: The results of the present study suggest that CMRI can be used to directly visualize swallowing dynamics and objectively evaluate the swallowing complaints of patients with oral cancer.

Hypopituitarism manifesting after invasive dental treatment in a patient with carcinoma of the tongue: a case report.

BACKGROUND: The symptoms of hypopituitarism are not usually discussed in the clinical setting of oral surgery. CASE PRESENTATION: We herein report a case of hypopituitarism that became evident after biopsy and extraction of several teeth in a 68-year-old man with tongue cancer. Three days after biopsy, the patient developed nausea and vomiting, and his serum sodium had fallen to 124 mEq/L. His serum cortisol concentration was low. Although the plasma concentration of adrenocorticotropic hormone (ACTH) was within the normal range, ACTH stimulation testing showed a lack of cortisol response. Given these findings, we suspected secondary adrenal insufficiency. To investigate the cause of secondary adrenal insufficiency, MRI of the head was performed, which revealed pituitary gland atrophy. The results of pituitary anterior lobe hormone-stimulation tests were compatible with hypopituitarism. Thirty days after biopsy, partial tongue resection was successfully performed under general anesthesia with perioperative hydrocortisone supplementation. CONCLUSIONS: We must be aware of various signs of hypopituitarism when we perform invasive dental treatment.

Oral diverticulum: a case report with histopathological findings.

Oral diverticulum is rarely encountered, and the histopathological findings are unclear. We herein report a case of an oral diverticulum and describe its histopathological findings. A buccal mucosal outpouching was observed in a 66-year-old man. Food debris was seen within the outpouching. Under the clinical diagnosis of a diverticulum-like lesion, excision of the outpouching was performed through an intraoral incision to stop food impaction. Histopathological examination revealed that the excised lesion was a true diverticular structure composed of a keratinising, squamous epithelial lining with a surrounding fibrous connective tissue wall, with inflammatory cell infiltration and haemorrhage. The histopathological diagnosis was a diverticular pouch of the buccal region. Clinicians should be aware of this lesion to ensure correct diagnosis and treatment.

Dense cancellous bone as evidenced by a high HU value is predictive of late implant failure: a preliminary study.

OBJECTIVES: The mechanism of late implant failure is unclear. This study examined the association between sclerosing cancellous bone images and the risk of late implant failures using multi-detector row computed tomography (CT) imaging data. METHODS: We performed a case-control study. The study group consisted of consecutive patients with implant failures treated at Kyushu Dental University between 2001 and 2016. CT data for late failure of 36 implants in 16 patients were available. The study cohort consisted of 16 patients with 36 late failed implants and 28 patients with 113 successful implants. RESULTS: The mean survival rate was 6.9 months for early implant failure, 76.6 months for late failure with marginal bone resorption, inflammation symptoms, and so-called peri-implantitis, and 95.0 months for late failure caused by implant fracture. The mean HU value for cases in the control group was 507 compared with 1231 for cases with late failure implants. Logistic regression was used for analysis. There were signs of high radiodensity of peri-implant cancellous bone when comparing adjusted radiodensity per 100 HU using CT data (OR 2.35; 95% CI 1.73-3.20; p < 0.001). CONCLUSIONS: Within the limits of our study, the presence of high radiodensity and cancellous bone consolidation on imaging may be related to risk factors for late implant failure. Therefore, CT images of the host cancellous bone status for observation of visible sclerosis could be a useful diagnostic indicator for late implant failure.

Significance and usefulness of imaging characteristics of gubernaculum tracts for the diagnosis of odontogenic tumors or cysts.

We aimed to determine the significance and usefulness of imaging characteristics of gubernaculum tracts (GT) for the diagnosis of odontogenic tumors or cysts. This was a retrospective analysis of relationships between odontogenic or non-odontogenic tumors or cysts and the GT that were visualized using multi-detector computed tomography (MDCT). The relationship between the size of a mass and expansion of the GT in all odontogenic tumors or cysts to which GTs were contiguous on MDCT, was statistically analyzed. Intact or expanded GTs were detected in MDCT images on the top of almost all odontogenic tumors or cysts, but not on non-odontogenic tumors or cysts. Characteristic image findings regarding the relationship between the GT and the odontogenic mass were detected for the respective odontogenic tumors or cysts in which the GTs were contiguous to the mass on MDCT. In ameloblastomas, expansion of the GTs significantly and very strongly correlated with tumor size (r = 0.741, p = 0.0001), but this correlation was very weak in dentigerous cysts (r = 0.167, p = 0.028) and there was no correlation between these parameters in odontogenic keratocysts (r = -0.089, p = 0.557). The imaging characteristics of GTs at the top of masses should be very useful for both the differential diagnosis of the pathological diagnosis of odontogenic masses and for differentiation between odontogenic and non-odontogenic masses.

Functional evaluation of swallowing in patients with tongue cancer before and after surgery using high-speed continuous magnetic resonance imaging based on T2-weighted sequences.

OBJECTIVES: The aim of this study was to determine the usefulness of evaluating the function of swallowing before and after surgery in patients with tongue cancer by using T2-weighted sequences of high-speed continuous magnetic resonance imaging (HSCMRI). STUDY DESIGN: The imaging findings and related parameters on HSCMRI along with those on routine MRI examinations before and after surgery were examined in 19 patients with tongue cancer. In addition, changes in various parameters during 1 year after surgery were evaluated in 10 patients. RESULTS: In most patients examined, the direction of flow to the esophagus could be seen on HSCMRI before and after surgery. Significant correlations were observed among 4 parameters and in the responses to a dysphagia questionnaire. CONCLUSIONS: The results of the present study suggest that the dynamics of swallowing can be directly visualized on HSCMRI by using 4 parameters that permit the evaluation of changes before and after surgery, and this enables objective evaluation of patients' swallowing complaints.

An unusually large osteochondroma of the mandibular angle: a case report.

BACKGROUND: Osteochondroma is a benign bone tumor that can occur in both the mesenchymal and craniofacial bones. However, craniofacial osteochondromas are extremely rare, because the mandible develops by intramembranous ossification rather than by endochondral ossification. CASE PRESENTATION: The most common site of craniofacial osteochondroma is the mandibular condyle, followed by the coronoid process. In the present study, we have described the case of a 64-year-old Japanese man with an unusually large osteochondroma located on the internal angle of the mandibular body. Clinical, radiological, pathological, and treatment-related aspects are discussed with respect to the tumor origins. CONCLUSIONS: In the medical literature, there have been few reports of large osteochondromas of the mandibular angle with no clinical symptoms.

Changes in the distributions of fluorine-18-labelled fluoro-2-deoxy-d-glucose accumulation into tongue-related muscles after dissection in patients with tongue cancer.

OBJECTIVES: To elucidate the changes in the distributions of fluorine-18-labelled fluoro-2-deoxy-d-glucose (18F-FDG) accumulation in the tongue muscles of patients following four kinds of surgical operations for tongue cancers. METHODS: The changes in the distributions of 18F-FDG accumulations in the tongue muscles on positron emission tomography (PET)-CT, in association with imaging findings on CT and MRI, were retrospectively analyzed before and after four kinds of surgical operations for 50 patients with tongue cancers. RESULTS: 18F-FDG-PET-positive areas appeared at the back of the intrinsic muscles of the tongue after invasive surgery for tongue cancers despite the absence of abnormal findings on CT and MRI. A correlation between the standardized uptake value maximum of 18F-FDG in the intrinsic muscles and the degree of invasiveness of the surgical procedures for tongue cancers (r = 0.539, p < 0.01) was found. CONCLUSIONS: It is important to pay attention to the changes in 18F-FDG distributions in the intrinsic muscles of the tongue before and after invasive surgery despite the absence of abnormal findings on CT and MRI when evaluating the tongue on 18F-FDG-PET.

Characteristics of the gubernaculum tracts in mesiodens and maxillary anterior teeth with delayed eruption on MDCT and CBCT.

OBJECTIVES: To elucidate the characteristics of the gubernaculum tracts (GTs) in maxillary anterior teeth with normal or delayed eruption and in mesiodens by using multidetector computed tomography and cone beam computed tomography. STUDY DESIGN: The characteristics of GTs in maxillary anterior teeth of 205 patients with impacted mesiodens were retrospectively analyzed by using multidetector computed tomography and cone beam computed tomography. The GTs of teeth with normal or delayed eruption and the GTs of mesiodens were examined. RESULTS: The detection ratio of GTs in impacted mesiodens and anterior teeth with delayed eruption was significantly lower than in teeth with normal eruption. A significant difference in the angulation was found between normal and delayed eruptions. Almost all detectable GTs in the inverted mesiodens were derived from the incisive canal, while the remaining were from the alveolar crest. The connecting area of major GTs to tooth in inverted mesiodens was the cervical or root area, but in all other anterior teeth, it was the crown area. CONCLUSIONS: GTs of inverted mesiodens may exhibit characteristics that are different from those of normal GTs when the teeth and/or the palate are developing.