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Year : 2022  |  Volume : 33  |  Issue : 4  |  Page : 356-362
Evaluation of wiping edible sesame oils in the oral cavities of hospitalised older patients who resist oral hygiene management

Department of Nursing Pathobiology, Graduate School of Nursing, Chiba University, Chiba, Japan

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Date of Submission13-May-2022
Date of Decision31-Aug-2022
Date of Acceptance31-Oct-2022
Date of Web Publication30-Mar-2023


Context: One of the causes of aspiration pneumonia is poor oral hygiene. We need care methods that caregivers can quickly, safely and inexpensively implement for convalescents with inadequate self-care. Edible sesame oil containing sesamin or sesaminol has already been shown to inhibit bacterial and fungal growth and have a vasodilating effect. Aims: The aim of this study is to evaluate the usefulness of using edible sesame oils for oral hygiene management. Settings and Design: This study evaluates an oral hygiene management method using two types of sesame oils in elderly hospitalised patients resistant to oral hygiene management. Methods and Material: The inpatients received oral care for 90 days. In the intervention groups, nurses brushed and wiped the oral cavity with roasted sesame oil (RSO) or sesame salad oil, while in the control group, care with tap water alone and brushing were done. Bacteria and Candida counts from tongue swabs, water content from the tongue's surface and cheek mucosa, oral health assessment tool (OHAT) and cytology of the cheek mucosa were assessed every 30 days before and after the intervention. Results: RSO showed a tendency to reduce the number of bacteria and Candida. There was an improvement in the OHAT scores with both oils. The water content or cytology was not changing. Conclusions: Sesame oils may improve oral hygiene and maintain health in older patients.

Keywords: Bacteria, candidiasis, mouth mucosa, oral hygiene, sesame oil

How to cite this article:
Ogawa T, Nishio J. Evaluation of wiping edible sesame oils in the oral cavities of hospitalised older patients who resist oral hygiene management. Indian J Dent Res 2022;33:356-62

How to cite this URL:
Ogawa T, Nishio J. Evaluation of wiping edible sesame oils in the oral cavities of hospitalised older patients who resist oral hygiene management. Indian J Dent Res [serial online] 2022 [cited 2023 Jun 9];33:356-62. Available from:

   Introduction Top

To prevent aspiration pneumonia, oral hygiene management is essential in nursing care.[1] However, there appears to be a lack of standard practice for oral hygiene.

In older adults, the secretion of saliva tends to decrease.[2],[3] As a result, their oral cavities can suffer from complications, such as dryness, increased membranous substances on the palates,[4] bacteria and fungi.[5] This further increases the risk of developing aspiration pneumonia.[1] Some people requiring nursing care who cannot brush their teeth dislike oral hygiene. Some people with cognitive disabilities are like this. These people are prone to aspiration pneumonia. These people need safe, effective and non-offensive care.

Many studies have reported oral hygiene methods using edible oils.[6],[7],[8],[9],[10] Several studies have reported that edible sesame oil reduces the number of bacteria and Candida albicans colonies in the oral cavity,[6],[9] improving mouth dryness and blood flow.

Sesame oil contains the elements sesaminol and sesamin. Sesamin inhibits the enzyme delta-5 desaturase.[11] This inhibition of delta-5 desaturase inhibits the synthesis of fungal cell-wall ergosterol. It also decreases the accumulation of dihomo-γ-linolenic acid and arachidonic acid. As a result, the vasodilator prostaglandin E1 increases and the arachidonic acid-derived pro-inflammatory chemical messengers leukotriene and prostaglandin E2 decrease, which may lead to vasodilation and suppression of inflammatory responses. Sesamin aids in increasing IgA concentration,[12],[13] while sesamin and sesaminol have vasodilatory and antioxidant properties.[14],[15] Sesaminol inhibited lipid peroxidation and lipid peroxidation more strongly than α-tocopherol and inhibited lipid peroxidation.[16] Sesaminol is contained in 80–100 mg/100 g in only sesame salad oil (SSO);[17] sesamin is contained in 800 mg/100 g in RSO and 450 mg/100 g in SSO.

Furthermore, the fatty acids in the oil inhibit the growth of certain bacteria and fungi.[18],[19]

Based on this literature, we hypothesised that oral care with RSO would reduce Candida in the oral cavity, and SSO would restore oral mucosa.

Previously, the same oral care methods were evaluated on older, bedridden patients who could not perform oral hygiene by themselves and were admitted to a nursing care facility.[10] The preliminary results of the intervention were inconclusive due to the small number of subjects and the 2 weeks period.

The present study's objective was to evaluate the effect of two kinds of sesame oil over 90 days of intervention on older patients who had resisted nurse-assisted oral care. We hypothesised that this method would reduce bacteria and Candida, moisturise the oral cavity and improve the oral mucosa and the overall oral condition of the participants in this study.

   Methods Top

Ethical considerations

The ethics committee of Chiba University's Graduate School of Nursing approved the study on February 20, 2018 (Approval No. 29–107). Participants were informed that their information would be kept confidential and used only for academic purposes. We guaranteed that participation in the study was voluntary and that there was no disadvantage if the patients did not consent to participate. If any intervention was made to aggravate the situation, we promised to stop it immediately.

We explained the details of the study to the participants. When a participant agreed, the participant or representative signed a consent form.

Design and settings

This study was a non-randomised controlled trial. It was conducted in three local hospitals in Japan, ranging from 175 to 370 beds. The intervention period was about 90 days (September 13, 2018, to February 17, 2019). It was challenging to obtain a lot of research cooperation from target facilities; therefore, the sample size was not calculated.


Participants were older inpatients [Figure 1], [Table 1]. The inclusion criteria were that the patients disliked assisted oral hygiene care and could not perform oral care independently. Two or more nurses judged whether prospective participants disliked assisted oral care. The exclusion criteria were patients with a history of sesame allergies, a temporomandibular disorder and a severely limited jaw range of motion.
Figure 1: Flowchart of the study

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Table 1: Demographic Data of Pre-intervention condition

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We used edible sesame oil for oral wiping: RSO (Baisen Koikuchi Goma Abura, Takemoto Oil & Fat Co.) and SSO (Taihaku Goma Abura. Takemoto Oil & Fat Co., Ltd.). We used tap water in the control group.

We assigned participants to one of three groups while ensuring the mean density of the oral cavity Candida spp. did not differ significantly between groups [Figure 1]. The day before the intervention, the presence of Candida was estimated by visual inspection (presence of white moss), and tongue surface samples were collected. Samples were cultured in the laboratory. Based on the visible inspection results, the patients were divided into groups. The results of the culture confirmed that there was no difference in the number of Candida carriers among the groups after the first intervention.

In the control group (Group A), a nurse or care worker orally swabbed the oral cavities of the participants with a stick sponge and tap water five times/day, including after the patient woke up, after every meal and before going to bed.

In the intervention groups (Groups B and C), a nurse or care worker brushed the intervention group patients' teeth with tap water and then wiped their oral mucosa and teeth with wrapped gauze around a toothbrush or a gloved finger with RSO in Group B and with SSO in Group C five times per day as same. They brushed once a day in all groups.

Before wiping, a wet gauze was used to moisturise their tongue when a participant's mouth was dry. About 1 mL of oil was dropped onto the gauze, which was used to wipe the surface of the patients' lips, teeth, upper palate, tongue and buccal mucosa from back to front. If there was too much debris in the oral cavity, a new gauze was used to clean the oral cavity until no dirt remained. Finally, the participants' oral conditions were confirmed and recorded.

Demographic data

We collected demographic data and medical information about the participants, including their age, gender, diagnosis and use of a nasogastric tube to determine oral intake status.

Oral condition assessment

We performed a sample collection and assessment on Days 0, 30, 60 and 90. A researcher collected the sample from the patients' tongues by collecting swabs back and forth three times on the dorsal surface of the tongue with a force of about 20 g. The swab was set in a bacterial counter (Saikin counter: Panasonic Co., Japan), and the number of bacteria on the swab was read.[20] All samples were taken to the laboratory and cultured in a Candida GS medium (Eiken Co., Japan) at 37°C for 48 h, and the colonies were counted. Pure cultures for the colonies were performed. The colonies were Gram-stained, which confirmed them to be yeast-like fungus. Glossal bacterial and fungal populations were expressed as a common logarithm (to base 10) of colony-forming units.

A researcher determined the water content of the tongue's surface and inside the cheek with a moisture checker (Mucus: Life Co., Japan). For the determination of dry mouth, a measured value of 29.6 or more was regarded as “normal,” 28.0–29.5 as “borderline,” and a steady amount of 27.9 or less as “dry”.[21] The oral cavity was assessed with an oral health assessment tool (OHAT).[22] All evaluation measures (lips, tongue, gums and tissues, saliva, natural teeth, dentures, oral cleanliness and dental pain) were examined.

The researcher also swabbed the inside of the cheeks to collect oral mucosa samples. Each specimen was stained by a cytologist with Papanicolaou stain and evaluated by Endo et al.[23] for classification, inflammatory changes, bacterial population and the presence of neutrophils and lymphocytes.

Data collection process

We explained the research and trained all the nurses and care workers on administering care before we began the intervention.

Data analysis

The primary outcome was the oral bacterial count. The log reduction value was calculated and analysed using Dunnett's test on the difference between Day 0 and each point and the intervention and control groups. When Candida spp. was not detected, the value was treated as one because we could not calculate the logarithm otherwise.

Water content and evaluation scores on the tongue surface and buccal side were analysed similarly. For water content, a Chi-square test was performed using the criteria of “normal,” “borderline,” and “dry.” We used JMP 14.4 for Windows (SAS, Cary, NC, USA) to analyse the data. Differences were assumed to be statistically significant if P < 0.05.

   Results Top

The 25 participants from 3 hospitals consisted of 13 men and 12 women [Table 1].

Bacterial count on the tongue

In Group B, it decreased gradually. However, there was no significant difference between Day 0 and each measuring date. In addition, no significant difference in measurements from Group A was observed [Table 2].
Table 2 : The difference of Data from Day0

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Candida spp. on the tongue

In Group B, it decreased over time. Day 0 was not significant on any evaluation days [Table 2].

Moisture on the tongue

There was no significant difference between Day 0 and each evaluation date or between different measurements in each group [Table 2].

In Group C, dryness decreased from 7 to 1, and normal moisture levels on the tongue increased from zero to three. There were no significant differences between the groups [Figure 2]a.
Figure 2: (a) Judgement of moisture of the tongue (b) Moisture of the cheeks

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One (Group C) also could eat solid food after 60 days. Her tongue was dry before the intervention (25.3). After 60 days, her tongue and cheek had normal moisture levels (30.4).

Moisture inside the cheek

In any group, there was no significant difference [Table 2]. There were no significant differences between Day 0 and Day 90 [Figure 2]b. In one subject (Group C), cheek moisture before the intervention was excessive (48.2), and the tongue was dry (18.6). After 60 days, the water content in the cheek had decreased (30.3).

Oral health assessment tool

A small score indicates an excellent oral cavity condition, and a lower rating indicates an improvement in the state of the oral cavity.

Total scores in Group C decreased gradually, and there was a significant difference between Day 0 and Days 60 and 90 [Table 2].

In evaluating each item, the OHAT scores decreased in the intervention groups for the tongue. The differences between the groups were significant on Day 30 [Table 2]. Regarding oral cleanliness, intervention groups showed a decrease, and there was a significant difference between Group A and Group B [Table 2] on Day 30 and Day 60. These were the only two measures that showed significant differences.

Oral mucosal cytology

In this evaluation, a more miniature score means a better mucosal condition. Any group had no significant differences between Day 0 and Day 90 [Table 2].

Individual subjects were evaluated for cytology. For example, one male participant (Group B) in his 70s with epilepsy was on oral intake. Dehydration progressed depending on the underlying disease from around Day 60, parenteral nutrition was administered to Day 90, and his general condition deteriorated. In this case, although the number of Candida spp. decreased, the number of bacteria and the OHAT score did not change. As shown in [Figure 3], the cytology improved about inflammatory changes, bacterial groups, neutrophils and lymphocytes, and the condition of the buccal mucosa was enhanced.
Figure 3: Oral mucosal cytology in 2 Group B participants (a):Buccal mucosal specimen on Day0 showing heavy inflammatory cell inflitration. (b) Decreased inflammatory cell infiltration shown in buccal mucosal specimen from same participant on Day60. (c):Massive bacterial aggregates (black/gray area) on buccal mucosal on Day0, d):Noticeably reduced bacterial aggregates on buccal mucosa from the same participant on Day90

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Adverse events

No adverse events occurred during the study period, and there was no interruption of patient care during the data collection process.

   Discussion Top

We hypothesised that the two sesame oils would suppress the growth of bacteria and Candida species in the oral cavity, moisturise the oral cavity and repair the oral mucosa, based on the known effects of sesamin and sesaminol.

Although the effect on bacterial numbers could not show a statistical tendency [Table 2], bacterial numbers with roasted sesame oil (RSO) showed a decreasing trend. It is possible that RSO, which is high in sesamin, may have affected the bacteria more substantially.

Recent research[24] shows that sesame oil may suppress plaque regeneration. The previous study[10] showed a decrease in oral Candida density. Although the number of subjects was small, this result shows the same trend as the results of previous studies.

We could not show the effect of oil wiping on improving oral dryness through changes in water content. Results from [Figure 2] suggest that mouth dryness may have been enhanced, but oil could have made it challenging to measure water content. In Group C, in one subject, excessive oral fluid was normalised and the risk of aspiration decreased, and another could also eat solid food after 60 days. The correction of excess or lack of water in the patients' mouths might have allowed the patients to chew food again.

The OHAT results might suggest that oil facilitated the removal of dirt and that administering oral care with oil improved the oral condition. It may benefit persons caring for their family since cleaning the oral mucosa and tongue is a safe and straightforward method.

There was no statistically significant change in the cytology scores from the inner cheeks. On the other hand, the scores of one subject with worsening disease improved. This suggests the potential of this method.

Despite implementing oral hygiene management using a different method to the standard care, there was no decrease in food intake. None of the patients discontinued the intervention. All patients could not communicate and assess the presence or absence of care distress. The scent and flavour of RSO may increase appetite and revive mental activity.[25] Since most of the subjects in this study had high appetites, it was not possible to clearly identify the effect. It may be effective if administered to the appropriate patients.

Oil and gauze are easier to obtain than commercial oral moisturisers; edible sesame oil has a pleasant scent, is affordable and easy to obtain and store and does not readily oxidise. Regarding the intervention cost, the oral moisturiser used in a previous study[26] cost RS 525/40 g, while the edible sesame oil used in our study cost RS 570/450 g. Therefore, oil wiping could be a potentially cost-effective oral hygiene method that moisturises the oral cavity.

Patients often resist assisted oral care, and some refuse help with oral hygiene care because of discomfort associated with the procedure. The causes of patients' resistance can also be fear and unfamiliarity with oral hygiene care. Therefore, patients need oral care that is painless, non-irritating and familiar. Most Asians are accustomed to sesame oil; hence, we assumed that the participants would find edible sesame oils acceptable. This study shows that this care is sustainable, less likely to be rejected and can maintain oral hygiene. It is necessary to evaluate the effect of oil wiping on appetite and the severity of pain during care for future consideration.

   Limitations and Future Challenges Top

The study had a minimal number of participants. The study design was a non-randomised controlled trial; hence, the evidence level is low. In future research, it will be necessary to expand the sample size and include subject randomisation in the study design to verify the effects of the intervention.

   Conclusions Top

RSO reduced the number of oral bacteria but did not reduce Candida spp. Both oils were shown to preserve oral hygiene. The study showed the potential to maintain oral health in patients with severe diseases.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.


We thank 25 participants and many nurses from the three hospitals for participating. We are also grateful to Dr. Nyamadzawo Amos. T. for his input on the survey.

Financial support and sponsorship

This work was supported by JSPS Early-Career Scientists Grant Number JP18K17455 and the Foundation for Total Health Promotion.

Conflicts of interest

There are no conflicts of interest.

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Correspondence Address:
Dr. Toshiko Ogawa
Graduate School of Nursing, Chiba University, 1-8-1, Inohana, Chuo-Ku, Chiba-City, Chiba 260-8672
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijdr.ijdr_410_22

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