Five types of health workers in this research were dentists (49.6%), general practitioners (12.5%), midwives (27.6%), health promotion officers (8.3%), and gynaecologists (2%) (Table 1). The dentist's response in this study was higher because the dentist got more online questionnaire links compared to other health workers.
4.2. Five Types of Indonesian Health Workers' Knowledge Regarding Oral Health Services for Pregnant Women
The knowledge of the health workers regarding the law, or governor's regulations, or regent/mayor regulations regarding the oral health of pregnant women, and also, regarding the socialisation of government regulations such as presidential regulations and their instruments regarding the oral health of pregnant women was in the 'less' criteria. These circumstances were similar to what Berman et al.  suggested that the policymakers lack understanding regarding the science-based public health policies. We may realise that science and policy will never be fully aligned. However, vital public health advances can still happen if scientists and other stakeholders synergise informing policy . The occurring gaps can hamper public health progress, especially for the group of pregnant women.
Most respondents knew the minimum number of visits of pregnant women to health services during pregnancy. Thus, the knowledge regarding such matter was in the 'good' criteria. The minimum visit during pregnancy is four times, as stated in the Republic of Indonesia Health Law No. 97 of 2014 regarding oral health care during pregnancy . Oral health services during pregnancy are performed at least four times during the gestational period. Once in the first trimester, once in the second trimester, and twice in the third trimester . There is a positive relationship between health care worker counselling through sharing sessions with pregnant women concerning the oral health care measure and its importance for a healthy pregnancy .
The health workers' knowledge regarding a particular desk for consultation services or oral health screening of pregnant women in the Integrated Healthcare Centre was in the 'less' category. These results are in consistent with the research’s findings conducted by Didah , which stated the lack of knowledge regarding Desk IV in the Integrated Healthcare Centre. Implementation of services in the Integrated Healthcare Centre is held in the five-desks system that includes: Desk I, which serves the registration and recording of infants, toddlers, pregnant women, nursing mothers, and spouses of childbearing age; Desk II, which serves the weighing; Desk III, which serves the filling of the Growth Chart (Kartu Menuju Sehat - KMS) based on the weighing results; Desk IV, which serves information on whether or not a baby or toddler is gaining weight, high-risk pregnant women, couples of childbearing age who are not yet acceptors of Family Planning Contraception (KB), health education and supplementary feeding services, oral rehydration therapy, vitamin A, iron tablets, condoms, Family Planning Contraception pills for repeated visits; Desk V, which provides immunisation, pregnancy check-ups, medical check-ups and medication, and Family Planning Contraception intrauterine device (KB IUD) services or injections . From interviews and observations, it was revealed that health workers rarely used these Integrated Healthcare Centre desks, and in this case, Desk IV, to provide oral health consultation or screening services. Also, the desks in the Integrated Healthcare Centre are often not fully available .
The health workers' knowledge regarding the necessity of oral health examination during pregnancy and to advise it to the pregnant women were in the 'good' category. These results, however, are different from the findings suggested by Muralidharan and Merrill , that only a few health care workers converse with pregnant women regarding oral health care during pregnancy , whereas this is very important to be done due to the insufficient knowledge related to oral care among pregnant women. Bamanikar and Kee  also stated that most (96.8%) pregnant women agree that they should have oral health examination during pregnancy; however, not all of them (55.9%) practice it, which raises serious concern since extra oral care for pregnant women is necessary due to susceptibility to gingival disease, which may induce low birth weight babies and premature births .
Knowledge of health workers regarding oral health care manual for pregnant women was found in the 'less' category. This result was shown from the fact that only 1 out of 191 health workers had any knowledge regarding this book, and this result also indicates that the goal of this book is not achieved, which should be a guideline for the maintenance of oral health in pregnant women and children under five for health workers in health service facilities, and used as a reference in the implementation .
In this study, only a few health workers had any knowledge of socialisation and training regarding manuals for maintaining oral health for pregnant women. This result, however, was not consistent with the research conducted by Suwargiani et al. , which stated that manuals with no socialisation and training would not increase the knowledge of an individual.
The health workers' knowledge regarding maternal and child health manual book was in the 'good' category. This result was supported by the research conducted by Khuzaiyah et al. , which also found that health workers are always encouraged to use the maternal and child health manual books as educational media for mothers and their families to motivate them to utilise the manuals more optimally. Knowledge of maternal and child health books is essential because comprehensive and integrated antenatal health services in public and private health facilities and private practitioners/clinics are necessary. This effort must include promotive, preventive, curative, and rehabilitative programs, and the manuals are amongst the instrument for reducing infant/maternal mortality .
The maternal and child health manual book contains essential information regarding maternal and child health. The maternal and child health manual book is not only used as a medium for documenting midwifery services but can also be used by mothers and families to increase knowledge regarding maternal and child health. Maternal and child health manuals are given to predetermined targets as an educational medium for midwives, to mothers and families to increase knowledge and attitudes so that their families can jointly raise the mother and children's health .
As many as 69% of health workers did not know about oral health services for pregnant women. This knowledge level was consistent with the Committee on Health Care for Underserved Women , which analysed postpartum survey data obtained from the Pregnancy Risk Assessment Monitoring System in 10 states. During pregnancy, 56% of mothers never had any oral treatment, and even 60% of them never brushed their teeth during their most recent pregnancy. This may be due to the lack of counselling from the health workers serving them in their chosen health facilities [18, 19]. Although most obstetricians acknowledged a dire need for oral health care during pregnancy, 80% of them never performed oral health screening interviews in every prenatal visit, while 94% did not refer all of their patients for a routine oral health examination . Most obstetricians and dentists agreed that oral health service for pregnant women is necessary. However, many dentists were also concerned with the safety of dental procedures and medications [17, 20].
Patient-centred care must be emphasised to be delivered by all health professionals as interdisciplinary team members. This treatment emphasizes evidence-based practice and also quality improvement and informative approaches. In the 21st-century health care system, providing patient-centred care is one of the core competencies that all health workers should possess. The health workers must be able to identify, respect, and care for the patients' differences, values, preferences, and expressed needs. This care system intends to relieve the patients' pain and suffering and provide continuous and coordinated treatment. The health workers need to listen, respond with precise information, and educate patients with two-way communication. Shared decision-making and management between health workers and patients must be implemented in any stage of treatment, as well as the continuous advocation of disease prevention, wellness, healthy lifestyle, which includes a focus on population health .