Factors affecting masticatory performance during the mixed dentition period.

BACKGROUND: During the mixed dentition period, masticatory performance may temporarily decline as deciduous teeth are replaced by permanent teeth. This may lead to an insufficient intake of chewy foods. OBJECTIVES: This study aimed to clarify the characteristics of factors that affect masticatory performance during the dentition exchange period. METHODS: The participants were 229 students in grades 4-6 who were in the lateral dentition exchange period. Shearing performance (SP) was evaluated using gummy jelly, and mixing performance (MP) was evaluated using colour-changing gum. The chewing rate, occlusal force and area, number of teeth, Hellman's tooth age, Rohrer index, grip strength and walking speed were also evaluated. The χ2 test, Mann-Whitney test, Spearman's rank correlation coefficient and a generalised linear model were used for statistical analysis. RESULTS: SP/MP showed a significant positive correlation with occlusal force, occlusal contact area and chewing rate for gummy jelly and gum but there was a difference in the strength of the correlation between boys and girls. Chewing rate for gummy jelly and gum showed a significant relationship with both SP and MP, suggesting that masticatory performance is higher with slower chewing. Maximum occlusal force was selected as a significant independent variable for SP, and Rohrer index was selected as a significant independent variable for MP. When the occlusal force was higher and the Rohrer index was lower, the masticatory performance tended to be higher. CONCLUSIONS: Our results suggest that masticatory performance during the dentition exchange period is higher with slower chewing and a stronger occlusal force, which may be related to obesity.

Compatibility of two types of gummy jelly tests for detecting decreased masticatory function.

OBJECTIVE: This study aimed to verify the compatibility of masticatory performance tests using different two types of gummy jellies. BACKGROUND DATA DISCUSSING THE PRESENT STATUS OF THE FIELD: Compatibility between the glucose concentration measuring method (GC) and 10-steps visual scoring method (VS), which are masticatory performance tests for diagnosing decreased masticatory function (DMF) in oral hypofunction and the use of different types of gummy jelly, has yet to be confirmed. MATERIALS AND METHODS: The participants consisted of 134 Japanese older people (51 men and 83 women). GC, VS and the increased surface area measuring method (ISA), as an alternative analysis method for VS, were conducted to evaluate masticatory performance. Cohen's Kappa coefficient was used to verify the consistency for detecting DMF between GC and VS. Pearson's correlation coefficient was used to analyse the relationship between GC and ISA. Each masticatory performance was compared among three different groups for the number of residual teeth. Cut-off values of VS and ISA for DMF that were consistent with GC were identified. RESULTS: Glucose concentration measuring method and VS showed an excellent consistency (Kappa coefficient = 0.86). There was a high positive correlation between GC and ISA (r = .70). However, the change in masticatory performance according to the number of teeth was different between GC and VS/ISA. The cut-off values of VS and ISA were a Score of 2 and 1687 mm2 , respectively. CONCLUSION: Glucose concentration measuring method and VS/ISA remained fairly consistent for detecting DMF, which might be useful information to interconnect the various studies on masticatory performance.

Factors Influencing Changes in Masticatory Performance as a Result of Wearing Removable Partial Dentures in Patients with Partially Edentulous Arches.

PURPOSE: To measure masticatory performance (MP) in partially edentulous patients when wearing removable partial dentures (RPDs) versus when not wearing RPDs, and to identify factors that could enable clinical evaluations related to differences in MP. MATERIALS AND METHODS: This study consisted of 87 partially edentulous patients (57 females, 30 males; mean age, 69.41 ± 8.85 years) categorized as Eichner classification B who habitually wore RPDs. MP was evaluated while wearing versus while not wearing RPDs using test gummy jellies. The participants were categorized into four groups by the presence of occlusal contacts in one to three of the molar and premolar regions (occlusal support), or in the anterior region only, according to the Eichner index (B1-B4). The participants were also categorized according to the jaw on which the RPDs were worn and the Kennedy classification, and evaluated in regard to changes in MP resulting from wearing RPDs. Additionally, the rate of change in MP (MP-rv) was calculated for each participant using MP when not wearing RPDs as a reference, and factors affecting MP-rv were evaluated using single or multiple regression analysis and the Kruskal-Wallis test with multiple comparisons. RESULTS: Significant increases in MP-rv were observed for all participants and for those with occlusal support in two (p = 0.006) and three regions (p = 0.019); however, no significant differences were observed when wearing and not wearing RPDs in participants with (p = 0.090) and those without occlusal support in one region (p = 0.474). With respect to the jaw on which the RPDs were worn, only maxillary or both maxillary/mandibular RPDs tended to have higher MP-rvs than did only mandibular jaws. The results of the multiple regression analysis showed that Kennedy Class I edentulous arches were a factor in increasing MP-rv (standard partial regression coefficient = 0.46, p < 0.05). CONCLUSION: According to the results of this study, among various factors on the degree of improvement in masticatory performance by wearing RPDs, bilateral missing posterior teeth might be a predictor for achieving clinical improvement.

[The Situation and Problems of Cancer Treatment at Designated Cancer Hospitals during the 2016 Kumamoto Earthquake].

The 2016 Kumamoto earthquake was the first disaster we experienced while pushing cancer medical collaboration systems under the second Basic Plan to Promote Cancer Control Programs.Soon after the earthquake, an earthquake investigation team comprising the representatives of several medical institutions was formed, and they performed a survey of the medical staff of every designated cancer hospital and other related institution.The importance of sharing information during disasters and the weaknesses of medical aspects and patients were clarified.We found it important to establish regional cooperation and a solid communication system during a disaster.For large-scale disasters, it is necessary to develop an informationsharing system that meets regional needs.

[Situation and Problems of Cancer Treatment Support Centers at Designated Cancer Hospitals of the 2016 Kumamoto Earthquake].

The 2016 Kumamoto earthquake occurred while the cancer consultation support center was being developed at each designated cancer hospital under the second Basic Plan to Promote Cancer Control Programs. After the earthquake, an earthquake investigation team was organized that consisted of the representatives of several medical institutions and researched the cancer support system of every cancer-related institution. Many problems in the cancer consultation supporting system became apparent. In large-scale disasters, the role of the cancer consultation support center is large, and it is important to improve information collaboration and the consultation support system adapted to the area.

Induction of the Histamine-Forming Enzyme Histidine Decarboxylase in Skeletal Muscles by Prolonged Muscular Work: Histological Demonstration and Mediation by Cytokines.

Recent studies suggest that histamine-a regulator of the microcirculation-may play important roles in exercise. We have shown that the histamine-forming enzyme histidine decarboxylase (HDC) is induced in skeletal muscles by prolonged muscular work (PMW). However, histological analysis of such HDC induction is lacking due to appropriate anti-HDC antibodies being unavailable. We also showed that the inflammatory cytokines interleukin (IL)-1 and tumor necrosis factor (TNF)-α can induce HDC, and that PMW increases both IL-1α and IL-1ß in skeletal muscles. Here, we examined the effects (a) of PMW on the histological evidence of HDC induction and (b) of IL-1ß and TNF-α on HDC activity in skeletal muscles. By immunostaining using a recently introduced commercial polyclonal anti-HDC antibody, we found that cells in the endomysium and around blood vessels, and also some muscle fibers themselves, became HDC-positive after PMW. After PMW, TNF-α, but not IL-1α or IL-1ß, was detected in the blood serum. The minimum intravenous dose of IL-1ß that would induce HDC activity was about 1/10 that of TNF-α, while in combination they synergistically augmented HDC activity. These results suggest that PMW induces HDC in skeletal muscles, including cells in the endomysium and around blood vessels, and also some muscle fibers themselves, and that IL-1ß and TNF-α may cooperatively mediate this induction.

Roles played by histamine in strenuous or prolonged masseter muscle activity in mice.

Bruxism and/or clenching, resulting in fatigue or dysfunction of masseter muscles (MM), may cause temporomandibular disorders. Functional support of the microcirculation is critical for prolonged muscle activity. Histamine is a regulator of the microcirculation and is supplied by release from its stores and/or by de novo production via the induction of histidine decarboxylase (HDC). Interleukin (IL)-1, a cytokine involved in temporomandibular disorders, is an inducer of HDC. In the present study, we examined the roles of histamine, HDC and IL-1 in MM activity. Experiments were conducted using our R+G+ model. A mouse restrained (R+) inside a narrow cylinder (front end blocked with a thin plastic strip) gnaws away (G+) the strip to escape, with the weight reduction in the strip serving as an index of MM activity. Fexofenadine (a peripherally acting histamine H1 receptor antagonist) reduced MM activity in normal mice. Both H1 receptor-deficient and HDC-deficient mice exhibited low MM activity. Prolonged R+G+ induced HDC activity in MM. Mast cell-deficient mice exhibited strikingly low HDC induction in MM (and also in the quadriceps femoris muscle) in response to muscle activity or IL-1ß. Mast cells were present around blood vessels and nerves in the epimysium and perimysium of MM. These results, together with others reported previously, suggest that: (i) peripheral histamine supports strenuous MM activity; (ii) strenuous MM activity stimulates mast cells to release histamine and to induce HDC (which replenishes the histamine pool in mast cells, possibly mediated by IL-1); and (iii) peripheral histamine H1 receptor antagonists may be effective in treating temporomandibular disorders or preventing prolonged clenching and/or bruxism.

Gliosarcoma with ependymal and PNET-like differentiation.

A rare case of gliosarcoma which arose in the temporal lobe of a 39-yearold man was reported. The gliomatous area of the tumor showed ependymal differentiation, and also contained immature neuroectodermal tissue resembling a primitive neuroectodermal tumor (PNET) in addition to an ordinary glioblastomatous component. Tumor cells in the PNET-like component were immunoreactive for synaptophysin, CD99, neurogenin 3, and α-internexin, but not for glial fibrillary acidic protein (GFAP), Class III-ß tubulin, or Neu N. The mesenchymal area exhibited a compact fascicular proliferation of atypical spindle cells invested by fine reticulin fibrils. In addition, these cells were immunoreactive for Slug and Twist - transcription factors which are involved in the "epithelial-mesenchymal transition (EMT)" phenomenon. Gliosarcomas containing an ependymal or PNET-like component are rare, and to our knowledge, the present case is the first to be reported whose glial element exhibited differentiation toward these two components. The diverse differentiation in the glial element suggests that the tumor most likely originated from primitive neuroepithelial progenitor cells rather than from the neometaplasia of a glioblastoma. The immunoreactivity for transcription factors in the mesenchymal element indicated that EMT might be involved in the pathogenesis of this very rare type of gliosarcoma.

[The Efficacy of CT angiography using the IVR-CT/angio system for surgical treatment of spinal hemangioblastoma].

We performed 3D-CT angiography (3D-CTA) with contrast injection to a feeding artery through a selectively introduced catheter into the intercostal artery in a patient with spinal hemangioblastoma. It revealed a relative three-dimensional (3D) anatomy between a tumor body, feeding arteries, draining veins, and surrounding vertebrae with superior resolution to 3D-CTA with intravenous contrast injection. This observation was used for preoperative planning facilitating tumor removal, through reconstructed 3D fly-through animation providing intraoperative identification and obliteration of feeding arteries. This examination was carried out without difficulty by utilizing IVR-CT/angio system (IVR: interventional radiology) which combines angiographic and CT equipment with a single fluoroscopy table, because it does not require a room-to-room transfer of the patient with the catheter left cannulated. DSA detection for any spinal lesions, neoplastic or vascular ones, is always better assisted by 3D-CTA with the IVR-CT/angio system (IVR-CTA).

The impact of a newly constructed removable denture on the objective and subjective masticatory function.

Purpose This study investigated the impact of the renewal of a removable prosthesis on the masticatory function by subjective and objective measures and its variation among the types of occlusal support.Methods Seventy-eight patients who received newly fabricated removable denture patients participated in this study. For the objective assessment, masticatory performance was measured using test gummy jelly. For the subjective assessment, standardized questionnaires about food acceptability and the oral health-related quality of life (OHRQoL) were used. Pre- and post-insertion assessments were performed for each subject. Subjects were divided into three groups according to their posterior occlusion: with posterior occlusion (w/PO), without posterior occlusion (w/o PO) and edentulous. Wilcoxon's signed rank test was used to compare the pre- and post-treatment measurements of each assessment. The analysis of covariance and a multiple comparison were used to assess the effect of new dentures and differences due to occlusal support.Results The masticatory performance, OHRQoL and food acceptability following prosthodontic treatment were significantly improved by new denture insertion. The masticatory performance among groups varied to a relative degree. The rate of masticatory performance improvement for edentulous subjects was twice that in w/PO subjects. The OHRQoL was significantly lower in the w/o PO and edentulous groups with old denture than patients w/PO. The food acceptability improved most markedly in the edentulous group.Conclusions The improvement in the masticatory performance by new denture insertion varied among types of occlusal support. Re-establishing the occlusal support of edentulous patients may help restore their OHRQoL and improve food acceptability.

Long-term feeding on powdered food causes hyperglycemia and signs of systemic illness in mice.

AIMS: Dietary habits are crucial factors affecting metabolic homeostasis. However, few animal experiments have addressed the effects of long-term feeding with soft food on parameters reflecting systemic health. MAIN METHODS: Using mice, we compared the effects of short (3 days) and long (17 weeks from weaning) feeding periods between powdered food and normal pellet food on the levels of blood glucose, serum levels of insulin, catecholamines, and corticosterone, blood pressure, and/or social interaction behaviors. In addition, the effects of a human glucagon-like peptide-1 analog, liraglutide (a new drug with protective effects against neuronal and cardiovascular diseases), were compared between the powder and pellet groups. KEY FINDING: (i) Powdered food, even for such a short period, resulted in a greater glycemic response than pellet food, consistent with powdered food being more easily digested and absorbed. (ii) Long-term feeding on powdered food induced hyperglycemia and related systemic signs of illness, including increases in serum adrenaline, noradrenaline, and corticosterone, higher blood pressures (especially diastolic), and increased social interaction behaviors. (iii) Liraglutide, when administered subcutaneously for the last 2 weeks of the 17-week period of feeding, improved these changes (including those in social interaction behaviors). SIGNIFICANCE: The hyperglycemia associated with long-term powdered-food feeding may lead to certain systemic illness signs, such as elevations of blood glucose, hypertension, and abnormal behaviors in mice. Mastication of food of adequate hardness may be very important for the maintenance of systemic (physical and mental) health, possibly via reduction in the levels of blood glucose and/or adrenal stress hormones (catecholamines and glucocorticoids).