Takuya Asaka

Mandibular osteoradionecrosis (ORN) is difficult to reconstruct because irradiated tissues are fibrotic and devitalized, and postoperative malalignment—particularly loss of condylar position—can compromise function and aesthetics. A 74-year-old man developed advanced right mandibular ORN after chemoradiotherapy for oropharyngeal carcinoma; conservative management failed, and segmental mandibulectomy was indicated. Reconstruction was performed with a left fibula free flap guided by an in-house computer-aided design/computer-aided manufacturing (CAD/CAM) workflow using patient-specific instruments (PSI), including mandibular and fibular cutting guides and a fibula assembly guide. The mandibular guide integrated anterior and posterior cutting components with stabilizing bars to help preserve mandibular continuity and condylar position, and aligned screw holes enabled accurate transfer of the virtual plan and facilitated plate fixation. Operative time was 9 h 58 min with an estimated blood loss of 700 mL. Postoperative imaging showed minor surface deviation of the reconstructed segment (<3 mm) with medial drift of the ipsilateral condyle (~7 mm). At 3 months, the patient maintained stable occlusion with a maximum mouth opening of 30 mm without complications. This case illustrates that PSI-guided fibula free flap reconstruction using an in-house CAD/CAM process can provide a practical and reproducible approach for advanced mandibular ORN while supporting postoperative mandibular alignment.

In mobile ad-hoc networks (MANET), multi-hop communication relies on a give-and-take relationship among users. For stimulating users to be more cooperative in MANET, an incentive mechanism that offers electric power in exchange for relaying packets by using wireless power transmission (WPT) technology has been proposed. To evaluate the availability of MANET and this incentive mechanism, it is important to reveal factors affecting to the user's willingness to relay packets. In this paper, we investigate and analyze user's willingness to relay through qualitative evaluations. On the basis of the analysis, we model user's willingness to relay packets depending on the residual battery level and user's characteristics. Finally, we also confirm that the electric incentive mechanism can stimulate reciprocal cooperation among users in MANET.

The research and development of technology for maintaining an information networks, which are an important lifeline in the event of a natural disaster such as an earthquake, is indispensable in large metropolitan areas. One of the characteristics of urban disasters is the occurrence of evacuees who form large crowds due to population congestion. Under such circumstances, delay-tolerant networking, which has conventionally been considered an effective means of communication at times of disaster, does not always work sufficiently. We propose a routing method that reduces the number of message transfers significantly compared to the conventional methods by focusing on the movement characteristics of the pedestrians. Moreover, the effectiveness of the proposed method is evaluated by computer simulation.

This paper proposes an electric power based incentive mechanism that source nodes compensate the electric power required for packet transmissions in mobile ad hoc network (MANET). Although MANET forces the relay cooperation on nodes for the multi-hop communication, the relay transmission consumes their resources for other nodes, which may cause nodes to be uncooperative. We assume electric power exchange between nodes, which has been getting practical in recent years. The proposed routing method uses incentive power based on the energy consumption for relaying packets as a metric. Computer simulation confirmed that the method implemented to AODV can reduce the power consumption on the relay nodes.

In recent years, small terminals such as smartphones equipped with various sensor functions have become widespread, and studies on wireless sensor networks and edge computing are advancing from the use of the latest technology such as Internet of Things (IoT) and intelligent transport systems. However, there are still many problems such as cooperation between edges and clouds, off-load, and how to realize orchestration. In addition, research on offloading when load conditions dynamically fluctuate and load balancing among edge servers has not been investigated. In this paper, we propose a load balancing method for an IoT sensor system using multi-access edge computing to equalize the load of edge servers when events such as a traffic congestion and guerrilla rainstorms occur.

Changes in facial bones may represent a manifestation of systemic disease. Dentists play an important role in the early detection of these manifestations of complex systemic diseases. A case of unusual maxillary mixed (osteoblastic and osteolytic) lesions as an initial manifestation of childhood acute myeloid leukemia (AML) is presented. A 12-year-old male patient was referred to the Department of Oral Medicine complaining of severe swelling in the right buccal region. 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) showed enhanced FDG uptake in the right maxillary sinus. In addition, PET maximum intensity projection image showed diffused FDG uptake in the entire bone marrow. Bone marrow aspiration was performed on the lumbar vertebra, and fluorescence in situ hybridization (FISH) demonstrated AML. The patient was diagnosed with AML (M5a) and treated with chemotherapy by the pediatric department. Six months later, the patient achieved complete remission. After chemotherapy, the disappearance of the osteoblastic and osteolytic lesion and 18F-FDG accumulation were confirmed by PET/CT. Dentists should be familiar with oral manifestations of leukemia because early detection of oral lesions would increase the life span of the patients and reduce the severity of complications.

The aim of the present study was to evaluate the effectiveness of platelet-rich fibrin (PRF) as a wound-healing accelerator in patients undergoing oral bisphosphonate therapy and requiring tooth extractions.