This study showed that pre-graduate education related to palliative care was inadequate in universities that trained dentists or dental hygienists compared to universities that trained nurses.

Many oral problems are reported in patients who are terminally ill. Therefore, dentists and dental hygienists are required to participate in palliative care teams in clinical practice. Wilberg et al. reported that the frequency of dry mouth, mouth pain, problems with food intake, oral candidiasis, and rich dental plaque were 78%, 67%, 56%, 34%, and 24%, respectively, in 99 patients with terminal cancer [8]. In a systematic review, Venkatasalu et al. found that xerostomia, oral candidiasis, and dysphagia were the three most common oral conditions among palliative patients, followed by mucositis, orofacial pain, taste change, and ulceration [6]. Professional oral care is a very important supportive care to provide quality care at end of life, and we think that it is important to clarify the current status of the integration of palliative medicine and dentistry.

In 1990, Brown et al. emphasized the importance of dental hygienists in an interdisciplinary team for palliative care, whose roles were educators, dental consultants, and primary care providers [9]. Ohno et al. stated that considering the high incidence of oral complications in patients with terminal cancer, dental services were necessary for high-quality palliative care, but there was insufficient availability [10]. Mol also reported that a trained dentist would be a good teammate for an oncologist, radiation therapist, or other doctors of a palliative care team [11]. According to this study, 47% of the hospitals with palliative care wards had dentistry, and 85.4%, which included hospitals without dentistry, could provide oral care by dentists and dental hygienists in the ward. Furthermore, since 2016, when oral care by dentists and dental hygienists for patients with a terminal illness has been covered by public medical insurance in Japan, the number of presentations on palliative care by dental hygienists at academic conferences has increased.

As described above, the participation of dentists and dental hygienists is required in the medical field of palliative care, and in fact, some dentists and dental hygienists should work as members of the palliative care team. Nevertheless, this study showed that both the extent and quality of palliative care education in universities that trained dentists and dental hygienists were currently extremely low. The nursing education model core curriculum (2017 revised edition) requires students to learn the following eight items related to palliative care: 1) Physical changes in people in the final stages of life, 2) Values, the outlook of life and death (Thanatology), 3) The importance of liaising with relevant agencies and professions, 4) Methods of assessment, control of pain, and total care for pain relief, 5) Acceptance process of death and spiritual care of the family, 6) The decision-making process, 7) Family care after death and grief care, and 8) The significance of care after death. However, this survey revealed that few dental hygienist training universities provide education on these contents [12]. Although lectures and practices on oral care in patients with terminal illness were given at some universities training dental hygienists, we believe that oral care of good quality cannot be provided without understanding the physical and mental conditions of end-of-life patients. These differences in the education of nurses and dental hygienists are thought to be because the scope of questions in the national examination includes palliative care in the former but not in the latter.

Education is conducted according to the model core curriculum at Japanese universities. The model core curriculum is defined by the Ministry of Education, Culture, Sports, Science, and Technology, and is an extraction of the core part that should be tackled in common by all universities. In addition, questions will be asked from this model core curriculum during national examinations for doctors, dentists, nurses, etc. Currently, the model core curriculum of medical education and nursing education includes a description of palliative medicine, but that of dentistry education does not contain a description of palliative medicine. Furthermore, the model core curriculum itself has not yet been formulated for dental hygienist education. In Japan, dental hygienists became a national qualification in 1948. The education period was required to be at least 2 years in 1983, and at least 3 years in 2010. Currently, there are 12 four-year universities, 16 junior colleges, and 146 vocational schools. Most dental hygienists are still educated in vocational schools. To enhance hygienist education, we believe that it is necessary to first enhance palliative care education at a four-year university and formulate a model core curriculum for that purpose.

This study showed that students from a university training dental hygienists were highly interested in palliative care, but felt that current palliative care education was inadequate, especially in the upper grades. It was also found that most of the education at universities training dental hygienists was related to the oral care of terminal patients and that the physical and mental conditions of end-of-life patients were not well educated. Many students were unaware of terms such as Angel care, grief care, spiritual pain, death care, and thanatology. To provide good oral care to patients who are terminally ill and improve their quality of life, this study suggests that it is necessary to enhance basic and clinical education on palliative care in universities that train dentists and dental hygienists.

This study has some limitations. First, we only examined the syllabus of universities and did not investigate its contents, so it is unclear whether the results obtained can be generalized. Second, dental hygienist training schools comprise not only universities but also junior colleges and vocational schools, but this study did not cover all dental hygienist education. However, since palliative care education is inadequate even in 4-year universities, which are considered to have the most extensive educational content, it can be inferred that palliative care education is also not sufficient in junior colleges and vocational schools. There is no selection by researchers because we examined all that were confirmed on the website, but selection bias may have occurred because it did not include those that were not posted on the website. In addition, since the questionnaire is a preliminary study only for students of the university to which the first author belongs, it may not reflect the intentions of all students. It is the first to investigate the current state of palliative care education in Japanese universities training dentists and dental hygienists. The participation of dentists and dental hygienists in a palliative care team is an urgent issue, and we think it is necessary to provide sufficient education in palliative medicine and care at universities training dentists and dental hygienists.