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Volume 61 (2021)
- Issue 2 Pages 33-
- Issue 1 Pages 1-
Volume 61, Issue 2
Displaying 1-8 of 8 articles from this issue
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Shumei Murakami, Atsutoshi Nakatani, Minami Majima, Tadashi Sasai, Yur ...2022 Volume 61 Issue 2 Pages 33-40
Published: 2022
Released on J-STAGE: April 06, 2022
JOURNAL FREE ACCESSThe main characteristics of alpha rays are that they contain a large amount of energy, but only travel short distances. Radiotherapy using alpha rays has been highly anticipated in recent years because it significantly damages cancer cells, but exposes the surrounding normal tissues to less radiation. In particular, alpha ray therapy has already been used to treat bone metastases. In addition, boron neutron capture therapy has started to be employed in the clinical setting.View full abstractDownload PDF (1176K)
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Marie Soga, Kouji Katsura, Taichi Kobayashi, Masaki Takamura, Akira Ku ...2022 Volume 61 Issue 2 Pages 41-46
Published: 2022
Released on J-STAGE: April 06, 2022
JOURNAL FREE ACCESSBackground and Purpose: Dental caries that arise after radiotherapy （radiation caries） can lead to reduced masticatory function caused by tooth loss and osteoradionecrosis caused by dental infections. There are two main opinions regarding the mechanism underlying radiation caries: 1） tooth fragility caused by the direct effects of radiation and 2） a reduction in the physiological effects of saliva due to hyposalivation and a worsening of oral status. However, it has not been clarified which of these mechanisms is the main cause of radiation caries. Therefore, the purpose of this study was to investigate the risk factors for radiation caries in patients who had received head and neck radiotherapy.
Material and Methods: Forty patients who had received head and neck radiotherapy were enrolled. We retrospectively investigated the relationships between radiation caries and clinical parameters, such as the treated site, irradiation field, radiation dose, and oral status, for 3 years after the completion of radiotherapy.
Results: The incidence rate of radiation caries was 85％. Twenty-two percent and 78％ of radiation caries occurred within and outside the irradiation field, respectively. The incidence rate of radiation caries among teeth within and outside the radiation field was 41.7％ and 57.7％, respectively. The occurrence of radiation caries showed a moderate positive correlation with plaque control records. On the other hand, it was not correlated with the total radiation dose, the mean radiation dose delivered to the parotid gland, or the amount of saliva.
Discussion: Our results suggested that radiation caries occur both within and outside the radiation field. It is considered that the risk of radiation caries is affected more by oral status, such as poor oral hygiene, than structural changes in teeth caused by radiation. Therefore, it is important to maintain a good oral status after head and neck radiotherapy to prevent radiation caries.View full abstractDownload PDF (1005K) -
- Sialoliths and Miscellaneous CalcificationMasayasu Tashiro, Atsutoshi Nakatani, Tomoaki Sano, Kazutaka Sugiura, ...2022 Volume 61 Issue 2 Pages 47-52
Published: 2022
Released on J-STAGE: April 06, 2022
JOURNAL FREE ACCESSObjectives: Previous studies have stated that multiple calcifications in the parotid gland （CPG） should be considered to be sialoliths, which are specific to Sjögren’s syndrome （SS）; however, other studies found that such calcifications are not always sialoliths and not always associated with SS. The aim of this study was to clarify whether CPG are always sialoliths, whether CPG are associated with SS, and whether CPG are associated with calcification of other parts of the head and neck region based on diagnostic images.
Materials and methods: The subjects were 18 patients who exhibited CPG on CT. The calcifications were divided into sialoliths （S） and miscellaneous calcifications （M） based on palpation and imaging findings. The number of calcifications, presence/absence of clinical symptoms, clinical complications, and calcification of other parts of the head and neck region were analyzed.
Results: CPG were classified as S and M in eight and ten cases, respectively. The number of calcifications per patient ranged from 1 to 3 in group S and from 1 to 9 in group M. All patients in group S exhibited symptoms in the parotid region, but only three patients （30.0％） did so in group M. One patient in each group had SS. Calcifications were observed in other parts of the head and neck region in 14 patients （77.8％）.
Conclusions: CPG are not always sialoliths and not always associated with SS. A high proportion of the patients with CPG had calcifications in other parts of the head and neck region. It is suggested that a relationship exists between CPG and calcifications in other parts of the head and neck region.View full abstractDownload PDF (518K)
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Tadanobu Aragaki, Kouji Katsura, Daijiro Kobayashi, Yasuyuki Michi, Yo ...2022 Volume 61 Issue 2 Pages 53-57
Published: 2022
Released on J-STAGE: April 06, 2022
JOURNAL FREE ACCESSIntroduction: Radiation-induced dental caries is a late oral adverse event that should be considered after head and neck radiotherapy. However, there are no clinical guidelines for dental management after head and neck radiotherapy. We report a case of multiple dental caries that developed after head and neck radiotherapy in a patient in whom symptomatic treatment was challenging.
Case: A 67-year-old male was referred to our department with difficulty with oral intake secondary to occlusal insufficiency. He had a history of radiotherapy for hypopharyngeal carcinoma, and nearly all of his teeth only had residual roots. We found multiple carious teeth, including in areas outside of the radiation field. We designed a temporary denture in coordination with a dental office; however, it was difficult to extract all of the patient’s teeth. The patient was followed-up; however, he died of esophageal cancer.
Conclusion: Radiation-induced dental caries can even occur in teeth outside of the radiation field. In such cases, continuous preventative measures, such as oral care, are important, even before the start of radiotherapy.View full abstractDownload PDF (944K) -
— Diagnostic Usefulness of MRI and Ultrasonography —Noriyuki Sugino, Hiroko Kuroiwa, Hizuru Osanai, Kozue Mori, Yutaka Kit ...2022 Volume 61 Issue 2 Pages 58-63
Published: 2022
Released on J-STAGE: April 06, 2022
JOURNAL FREE ACCESSAn arteriovenous malformation （AVM） is a congenital abnormality caused by vascular dysplasia, in which an artery and a vein communicate directly without passing through the normal capillary network. AVM rarely develop in the oral and maxillofacial region, especially in the jaws. We present a case in which a mandibular tumor or cyst was clinically suspected, but an AVM was diagnosed based on radiological examinations.
A 13-year-old male visited our hospital with a chief complaint of mobility of the lower right first molar after having clashed with his friend. Abnormal findings, including a multilocular region of radiolucency with a partial honeycomb-like region extending from the lower right first premolar to the right mandibular ramus, were observed on panoramic radiography. The swelling of the lesion, which had an internal septum; bone resorption around the mandibular foramen; and the expansion of the mandibular canal at the mandibular ramus were observed on computed tomography. Ultrasonography （US） showed abundant, fast-flowing blood in the lesion. Magnetic resonance imaging （MRI） showed expanded blood vessels with flow voids in the anterior part of the right parotid gland on T1-weighted imaging. Fat-suppressed T2-weighted imaging showed a flow void covering most of the lesion. Consecutive AVM from the external carotid artery and nidus in the facial and maxillary arteries were observed on MR angiography.
There was no recurrence after vascular embolization. It is difficult to confirm the presence of an intraosseous AVM in the jaws based on conventional X-ray radiography alone. MRI and US can help to visualize vessels with high blood flow in such lesions.View full abstractDownload PDF (803K)
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Yusuke Kawashima, Masaaki Miyakoshi, Yoshihiro Kawabata, [in Japanese] ...2022 Volume 61 Issue 2 Pages 64-68
Published: 2022
Released on J-STAGE: April 06, 2022
JOURNAL FREE ACCESSDownload PDF (664K) -
Yusuke Kawashima, Hiroshi Abe, Masaaki Miyakoshi, Yoshihiro Kawabata, ...2022 Volume 61 Issue 2 Pages 69-71
Published: 2022
Released on J-STAGE: April 06, 2022
JOURNAL FREE ACCESSDownload PDF (526K)
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Ko Dezawa, Kunihito Matsumoto, Motohiro Ito, Toshihiko Amemiya, Kazuya ...2022 Volume 61 Issue 2 Pages 72-79
Published: 2022
Released on J-STAGE: April 06, 2022
JOURNAL FREE ACCESS
Introduction: Modern dental education programs in Japanese dental colleges require students to gain a vast amount of knowledge as efficiently as possible. With this aim, we devised a low-cost e-learning system, which utilized the students’ mobile devices, a laptop personal computer （PC） as a server, and the dental school’s existing intranet.
The e-learning system employed multiple-choice questions （MCQs）, and students were required to answer correctly to move to the next question. Thus, all students were required to correctly answer all questions. The present study aimed to evaluate the usability and effectiveness of the e-learning system based on a questionnaire completed by the students.
Methods: The e-learning system was tested on 151 fourth-year dental students, who were taking a dental radiology class at Nihon University School of Dentistry, Japan. An intranet was constructed using a low-end laptop PC and a wireless router designed for home use. The system was developed in Hypertext Markup Language （HTML）, Hypertext Preprocessor （PHP）, and My Structured Query Language （MySQL）. More than 400 MCQs related to oral radiology were registered in the e-learning system. Students could view and answer the MCQs on their mobile phones and tablets via internet browsers at any time. After completing the e-learning, students evaluated the system by completing a questionnaire set up in Google Forms.
Results: We received 150 responses to the questionnaire （response rate: 99.3％）. Fifty-eight percent of the respondents considered that the e-learning system was effective. Opinion was divided about the need to provide a correct answer to move to the next question.
Conclusion: This e-learning system may increase students’ motivation for learning and improve their understanding by enabling them to study during their free time. Improvements will be made to the e-learning system and its application based on the suggestions of the students who completed the questionnaire.View full abstractDownload PDF (1142K)
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