Estimated effectiveness of school closure and voluntary event cancellation as COVID-19 countermeasures in Japan

BackgroundAs countermeasures against the COVID-19 outbreak, sports and entertainment events were canceled (VEC) in Japan for two weeks from 26 February through 13 March. Moreover, most schools were closed (SC).ObjectiveFor this study, we estimated the basic reproduction number (R₀) and SC and VEC effects.MethodAfter constructing a susceptible–infected–recovered model with three age classes, we used data of symptomatic patients in Japan for 14 January through 24 March. The SC and VEC effects were incorporated into the model through changes in contact patterns and contact frequencies among age classes.ResultsResults suggest R₀ as 2.56, with 95% CI of [2.51, 2.96] before SC and VEC. The respective effects of SC and VEC were estimated as 0.4 (95% CI [0.3, 0.5]) and 0.5 (95% CI [0.3, 0.7]).ConclusionThe estimated R₀ is similar to those found from other studies of China and Japan. Significant reduction of contact frequency has been achieved by SC and VEC. Nevertheless, its magnitude was insufficient to contain the outbreak.     

DENTAL MATURITY AS AN INDICATOR OF CHRONOLOGICAL AGE: RADIOGRAPHIC ASSESSMENT OF DENTAL AGE IN A BRAZILIAN POPULATION

Objective:

The purpose of this investigation was to evaluate the applicability of the methods proposed by Nolla and by Nicodemo and colleagues for assessing dental age and its correlation to chronological age.

Methods:

Panoramic radiographs of 360 patients from the city of Fortaleza (CE, Brazil) aged 7-15 years were used to assess the associations between dental and chronological age. Data were submitted to statistical analysis using the BioEstat 2.0 (2000) software. Student-Neuman-Keuls test was performed and Pearson''s correlation coefficients were calculated at 5% significance level.

Results:

When the Nolla method was applied, the mean difference between true and estimated age for males and females was underestimated. The use of the method proposed by Nicodemo and colleagues also resulted in underestimation, although it was more evident in male subjects. The correlation coefficients between chronological age and estimated dental age were high, with mean values ranging between 0.87 and 0.91 for males and between 0.84 and 0.93 for females.

Conclusion:

Although both methods proved to be reliable in estimating age, the use of correction factors is recommended.     

Immunohistochemical study of hard tissue formation in the rat pulp cavity after tooth replantation

While mineralized tissue is formed in the pulp cavity after tooth replantation or transplantation, little is known of this hard tissue formation. Therefore, we conducted histological and immunohistochemical evaluations of hard tissue formed in the pulp of rat maxillary molars after tooth replantation. At 5 days after replantation, degenerated odontoblasts were lining the pulp cavity. At 14 days, dentin- or bone-like tissue was present in the pulp cavity. Immunoreactivity for osteopontin (OPN) and bone sialoprotein (BSP) was strong in the bone-like tissue, but weak in the dentin-like tissue. Conversely, dentin sialoprotein (DSP) was localized in the dentin-like tissue, but not in the bone-like tissue. Cells positive for BMP4, Smad4, Runx2, and Osterix were found around the blood vessels of the root apex at 5 days. At 14 days, these cells were also localized around the bone-like tissue. Cells expressing alpha-smooth muscle actin (SMA) were seen around the newly formed bone-like tissue, whereas no such cells were found around the newly formed dentin-like tissue. In an experiment involving the transplantation of a green fluorescent protein (GFP)-transgenic rat tooth into a wild-type rat tooth socket, GFP-positive cells were detected on the surface of the bone-like tissue and over all dentin-like tissue. These results indicate that the original pulp cells had the ability to differentiate into osteoblast-like cells as well as into odontoblast-like cells.     

Evaluation of the effect of a stabilization splint on occlusal force in patients with masticatory muscle disorders

The purpose of this study was to evaluate the effect of stabilization splint therapy on occlusal force in patients with masticatory muscle disorders (MD). Six female patients with myalgia or myofascial pain participated in this study. The occlusal points and load on the dental arch in maximum clenching was measured using the computerized system with Dental Prescale(R) before and after the use of the splint. There were no significant changes in the number of occlusal points, mean occlusal pressure, and asymmetry in occlusal balance between before and after the use of the splint. However, there were significant differences in the extent of the area of occlusion and in the integrated occlusal loads. The integrated occlusal load converged to the normal level with the use of the splint. From the results of this study, it is suggested that the use of the stabilization splint has the effect of normalizing the occlusal force.     

Changes in collagen types during the healing of rabbit tooth extraction wounds

Three alpha chains of type V collagen--alpha 1 (V), alpha 2 (V), and alpha 3 (V)--were initially demonstrated together with the expected collagen types I and III in the pepsin-soluble fraction of both normal mandibular bone and tooth extraction wound tissues of rabbits, as analyzed by sodium dodecyl sulfate-gel electrophoresis. The total collagen content of each extraction wound, as determined by the hydroxyproline assay, was observed to increase continuously from day 5 through day 17 and then leveled off or decreased. The ratio of type V to type I collagen was significantly higher in the initial stage of wound healing and decreased sharply down to the level of mandibular bone by day 5. The ratio of type III to type I collagen in the pepsin-soluble fraction increased and reached a maximum on day 5, whereas it was maximal on day 7 in the cyanogen bromide-soluble fraction, and thereafter decreased gradually in both fractions. The ratio for the pepsin-soluble fraction was, however, significantly higher than that for the cyanogen bromide-soluble fraction in the early stage of wound healing.     

Dental rehabilitation using an implant-carrying plate system in a severely resorbed edentulous maxilla: a case report

This clinical article describes a case of dental rehabilitation using an implant-carrying plate system (EPITEC) for a patient with severely resorbed edentulous maxilla and microstomia. In this case, the presence of microstomia prevented bone augmentation procedures through an intraoral approach. Treatment using 2 endosseous implants inserted in the canine regions and an implant-supported overdenture was planned. However, endosseous implants were not feasible on the right side because of insufficient available bone volume. An implant-carrying plate system was then utilized on the right side. Four months later, an implant-supported ball-attachment overdenture was fabricated. At the 2-year follow-up, the clinical course remained uneventful, and the patient remained satisfied with the treatment.     

Reliability of a negative clinical temporomandibular joint examination: prevalence of disk displacement in asymptomatic temporomandibular joints

Unilateral temporomandibular joint arthrography was performed in 40 healthy volunteers with asymptomatic and clinically normal temporomandibular joints. Thirty-four joints (85%) showed superior disk position, and six joints (15%) were radiographically abnormal with displacement of the disk. Thus, two showed anterior displacement, one showed rotational anterolateral displacement, one showed rotational anteromedial displacement, one showed sideways lateral and one showed sideways medial displacement. Thus, a negative clinical examination for temporomandibular joint internal derangements may involve a risk of being false-negative. All but one of the joints showed normalization of disk position during opening, and it is suggested that lack of functional disturbances accounts for the freedom of symptoms.     

ASO Visual Abstract: Preoperative FDG Positive Lymph Nodes Predict the Postoperative Prognosis in Resectable Biliary Tract Cancers

Annals of Surgical Oncology -     

Predictive Ability of the Five-time Chair Stand Test for Postoperative Pneumonia after Minimally Invasive Esophagectomy for Esophageal Cancer

Annals of Surgical Oncology - The revised sarcopenia guidelines proposed handgrip strength (HGS) and five-time chair stand test (5-CST) as the primary parameters of muscle function. HGS and 5-CST...