Influence of mandibular incisor agenesis and growth pattern on symphysis characteristics: A retrospective cephalometric study.

OBJECTIVE: This study was performed to investigate the effects of mandibular incisor (MnI) agenesis and divergent malocclusion type on mandibular symphysis inclination and morphology. METHODS: A total of 162 selected patients were divided into two groups: one group consisted of patients with one or two congenitally missing MnIs, and another group comprised patients without tooth agenesis. Patients in each group were categorized into three divergent malocclusion groups (hypodivergent, normodivergent and hyperdivergent) according to the Frankfort mandibular plane angle, with 27 patients per group. Lateral cephalograms were used to evaluate mandibular symphysis inclination and morphology. Two-way analysis of variance, simple main effect analysis and Tukey's test were used for statistical comparisons. RESULTS: The agenesis group demonstrated a significantly greater retroclination of the mandibular symphysis than the non-agenesis group in the normodivergent group. In the hypodivergent and normodivergent groups, the agenesis group showed a significantly smaller area of the alveolar bone with thinner width and shorter height than the non-agenesis group. CONCLUSION: For the Japanese orthodontic patients, MnI agenesis caused a significantly great retroclination of the mandibular symphysis in patients with normodivergent malocclusion and significantly small area of the alveolar bone with thin width and short height in patients with hypo- and normodivergent malocclusions.

Design of palatal and lingual augmentation prostheses by using an intraoral scanner for a patient after a glossectomy: A clinical report.

Computer-aided design and computer-aided manufacturing was used to fabricate palatal and lingual augmentation prostheses for a patient with dysphagia after a glossectomy. The function of these prostheses was comparable with that of those fabricated by conventional methods. The patient outcome suggests that an intraoral scanner can be effectively used for the fabrication of augmentation prostheses for patients with dysphagia and a high risk of aspiration.

Notch Signaling Affects Oral Neoplasm Cell Differentiation and Acquisition of Tumor-Specific Characteristics.

Histopathological findings of oral neoplasm cell differentiation and metaplasia suggest that tumor cells induce their own dedifferentiation and re-differentiation and may lead to the formation of tumor-specific histological features. Notch signaling is involved in the maintenance of tissue stem cell nature and regulation of differentiation and is responsible for the cytological regulation of cell fate, morphogenesis, and/or development. In our previous study, immunohistochemistry was used to examine Notch expression using cases of odontogenic tumors and pleomorphic adenoma as oral neoplasms. According to our results, Notch signaling was specifically associated with tumor cell differentiation and metaplastic cells of developmental tissues. Notch signaling was involved in the differentiation of the ductal epithelial cells of salivary gland tumors and ameloblast-like cells of odontogenic tumors. However, Notch signaling was also involved in squamous metaplasia, irrespective of the type of developmental tissue. In odontogenic tumors, Notch signaling was involved in epithelial-mesenchymal interactions and may be related to tumor development and tumorigenesis. This signaling may also be associated with the malignant transformation of ameloblastomas. Overall, Notch signaling appears to play a major role in the formation of the characteristic cellular composition and histological features of oral neoplasms, and this involvement has been reviewed here.

Effects of the Geometrical Structure of a Honeycomb TCP on Relationship between Bone / Cartilage Formation and Angiogenesis.

A number of biomaterials have been developed, some of which already enjoy widespread clinic use. We have devised a new honeycomb tricalcium phosphate (TCP) containing through-and-through holes of various diameters to control cartilage and bone formation. However, the way in which the geometric structure of the honeycomb TCP controls cartilage and bone tissue formation separately remains unknown. In addition, an association has been reported between bone formation and angiogenesis. Therefore, in the present study, we investigated the relationship between angiogenesis and various hole diameters in our honeycomb TCP over time in a rat ectopic hard tissue formation model. Honeycomb TCPs with hole diameters of 75, 300, and 500 µm were implanted into rat femoral muscle. Next, ectopic hard tissue formation in the holes of the honeycomb TCP was assessed histologically at postoperative weeks 1, 2, and 3, and CD34 immunostaining was performed to evaluate angiogenesis. The results showed that cartilage formation accompanied by thin and poor blood vessel formation, bone marrow-like tissue with a branching network of vessels, and vigorous bone formation with thick linear blood vessels occurred in the TCPs with 75-µm, 300-µm, and 500-µm hole diameters, respectively. These results indicated that the geometrical structure of the honeycomb TCP affected cartilage and bone tissue formation separately owing to the induced angiogenesis and altered oxygen partial pressure within the holes.

Central dentinogenic ghost cell tumor of the maxilla: a case report with new imaging findings and review of the literature.

A dentinogenic ghost cell tumor (DGCT) is a rare benign odontogenic tumor that commonly shows characteristics of solid proliferation and has a relatively high risk of recurrence after surgical treatment. We herein report a case of a central DGCT that occurred in the maxilla and resulted in bone expansion. This study highlights new imaging findings (particularly magnetic resonance imaging) along with histopathological observations. In addition, we conducted a review of the existing literature on this rare tumor. A 37-year-old man developed swelling around the right cheek. A benign odontogenic tumor such as ameloblastoma was suspected based on the imaging examination findings (including bone expansion and the internal characteristics of the tumor) on panoramic imaging, computed tomography, and magnetic resonance imaging. The lesion was surgically excised from the right maxilla. Postoperative histopathological examination led to a definitive diagnosis of central DGCT. The tumor comprised epithelial neoplastic islands, resembling ameloblastoma, inside tight fibroconnective tissue; masses of ghost cells and formation of dentin were also observed. We had suspected that the minute high-density region around the molars on the imaging examinations represented alveolar bone change; however, it represented dentin formation. This led to difficulty diagnosing the lesion. Although DGCT may present characteristic findings on imaging examinations, its occurrence is infrequent, and in some cases, the findings may include the presence or absence of an impacted tooth without obvious calcification. The present case suggests that we should consider the possibility of an odontogenic tumor with calcification when high-density structures are observed inside the lesion.

Disease resistance and growth promotion activities of chitin/cellulose nanofiber from spent mushroom substrate to plant.

Some studies have reported the method for treating the spent mushroom substrate (SMS). However, the effective use as a functional raw material based on properties of SMS remains a formidable challenge. In this study, we investigated the usefulness of SMS in agriculture to develop a new method for treating and utilizing it. First, we attempted to isolate chitin/cellulose nanofiber complex (CCNFC) from SMS using chemical pretreatment and mechanical fibrillation. The characterization results like SEM, FT-IR, and XRD showed that we successfully isolated the CCNFC from SMS. Second, we explored the biological activities of the CCNFC for its potential application as a functional agricultural nanomaterial. CCNFC water dispersion with low concentration (0.1 and 1 mg/mL) exhibited significant plant disease resistance and plant growth promotion activities. Our results suggested that SMS may provide a useful source of functional agricultural nanomaterial, which may contribute to treating and applying it in agriculture.

Relationship between jaw-opening force and neck circumference in healthy older individuals.

AIM: In recent years, the relationships of arm circumference and calf circumference with swallowing function have been reported. However, the efficacy of using the neck circumference, which is closer to the swallowing-related muscles, has never been verified. Jaw-opening force, an indicator of suprahyoid muscle strength, is known to be useful for screening for dysphagia. The aim of the present study was to identify the relationships between neck circumference and swallowing-related muscle strength, and to clarify the association between these variables in older individuals. METHODS: A total of 104 healthy, independent older individuals, aged ≥65 years (36 men, 68 women, mean age 71.5 ± 4.5 years, range 65-83 years), participated in the study. Neck circumference, arm circumference, calf circumference, jaw-opening force and repetitive saliva swallowing test scores were measured. Multiple regression analysis was carried out to determine the relationship between neck circumference and jaw-opening force, between neck circumference and repetitive saliva swallowing test score, and to identify variables affecting jaw-opening force and neck circumference. RESULTS: The participants' mean body mass index was 22.8 ± 2.9 (range 15.8-32.4). Sex and neck circumference, but not arm or calf circumference, were significant independent factors related to jaw-opening force. Independent factors affecting neck circumference were sex, body mass index, jaw-opening force and arm circumference, but not repetitive saliva swallowing test score. CONCLUSIONS: In healthy older individuals, neck circumference was more strongly related to jaw-opening force than were arm or calf circumference. This suggested that neck circumference could be useful for evaluating swallowing-related muscle strength non-invasively and easily. Geriatr Gerontol Int 2019; 19: 330-334.

Relationship between swallowing muscles and trunk muscle mass in healthy elderly individuals: A cross-sectional study.

BACKGROUND AND OBJECTIVE: A decrease of swallowing muscle strength causes dysphagia, and a relationship between swallowing muscle strength and appendicular muscle mass has been reported. Moreover, the effect of trunk retention function on swallowing function has been clinically recognized. However, the relationship between trunk muscle mass and swallowing muscle strength is unclear. We aimed to clarify the association between these variables in elderly individuals. METHODS: Subjects were 118 healthy community-dwelling individuals aged ≥65 years (men: 37, women: 81). We measured total muscle mass, grip strength, jaw-opening force, tongue pressure, cross-sectional area (CSA) of the geniohyoid muscle, and tongue muscle thickness. The appendicular skeletal muscle mass index (ASMI) and trunk muscle mass index (TMI) were calculated based on the appendicular skeletal muscle mass and trunk muscle mass, and corrected by height squared. Multiple regression analysis was performed with jaw-opening force and tongue pressure as dependent variables and with age, sex, grip strength, ASMI, TMI, CSA of the geniohyoid muscle, and tongue muscle thickness as independent variables. RESULTS: Significant explanatory factors for jaw-opening force were sex (p = 0.002) and TMI (p = 0.003). Significant explanatory factors for tongue pressure were aging (p = 0.001), tongue muscle thickness (p = 0.027), and TMI (p = 0.033). CONCLUSIONS: Until now, the relationship between swallowing muscles and whole body muscle mass has been reported using ASMI as the indicator of whole body muscle mass. This study suggests that TMI may be used as a highly relevant indicator of swallowing muscles rather than ASMI.