1. Introduction
Oral health is a fundamental right of all people enabling them to enjoy a high quality of life [
1]. It is an integral part of general health and a crucial element of healthy ageing [
2]. Oral diseases should be addressed among other non-communicable diseases as a global public health priority [
1,
3], and countries should promote universal health coverage for oral health by 2030 [
4]. Moreover, there is a growing interest in the association between oral and general health and the identification of oral health indicators with high prognostic or diagnostic value for general health deterioration [
5,
6].
One of the main causes of oral conditions, such as dental caries and periodontal disease, as well as systematic infection, is plaque accumulation due to poor oral hygiene. Periodontal disease and poor oral hygiene in teeth and dentures have been associated with aspiration pneumonia in hospitalised patients and nursing home residents [
7,
8]. Further, denture wearing during sleep has been associated with a 2.3-fold higher risk of the incidence of aspiration pneumonia in community-dwelling older people [
9]. To reduce the number of respiratory pathogens, meticulous dental and denture hygiene and removal of dentures at night are among the recommended measures to prevent aspiration pneumonia in frail older adults [
7,
10]. According to the Japanese Society of Gerodontology, poor oral hygiene is one of the signs of oral hypofunction that may lead to oral frailty [
11].
Three European expert reports by dentists, physicians and dental hygienists working with older people described the necessary measures to promote oral health in older people [
12,
13,
14]. Among these measures are brushing the teeth at least twice a day with a toothbrush and fluoride toothpaste, cleaning the interdental spaces at least once a day, brushing the dentures at least twice a day with a nonabrasive denture cleanser or liquid soap combined with chemical cleansing agents, and removing the dentures during sleep.
However, although the above daily practices are easy to perform by older individuals (and their carers) and can prevent many oral and general conditions, neglected oral hygiene and poor daily oral care practices are common among older adults [
3,
8,
15,
16,
17,
18,
19,
20].
Several structural, intermediate and proximal determinants affect oral health in older adults, including poor general health, frailty, care dependency, poor oral health literacy, negative or wrong beliefs and attitudes towards oral health, lack of interest in oral health, limited professional advice, inadequate oral health policies and commercial activities/information which may manipulate their behaviour [
3,
4,
13,
19,
21,
22,
23].
Dental patients are exposed to various sources of oral health information, including dental professionals, other healthcare workers, relatives, friends, or the media [
24,
25]. Young and middle-aged people in Iran received oral health information mainly from dentists and television/radio [
24]. A study among Brazilian denture wearers with a mean age of 62 years has shown that 77.5% had not received any instructions on denture cleansing and 77.1% on oral care, while an association was recorded between the lack of instructions regarding oral care and the presence of denture stomatitis [
26].
Poor professional support from dentists and other healthcare providers, including inadequate, inefficient or ineffective instructions on daily oral hygiene, may lead to poor daily oral care practices and various oral and systemic conditions. However, data on the sources of oral hygiene instructions among community-dwelling older people and their association with performing the recommended oral hygiene practices are scarce. Therefore, the purpose of this study was to explore the sources of daily oral hygiene and care information among urban community-dwelling older adults and associate them with their dental and denture care habits.
4. Discussion
Under the limitations of the present study, the participants had received daily oral hygiene and care information from various sources, including dentists, media (television, magazines and the internet), formal education, relatives, friends, and other care providers, such as pharmacists and dental technicians. The oral care information obtained from dentists was associated with better adherence to the currently recommended daily oral care practices for both teeth and dentures for older adults. However, many participants reported that they had not received any kind of oral hygiene information. Moreover, for many participants, the reported dental and denture daily care habits were poor.
Almost half of the dentate participants reported that they had obtained toothbrushing instructions from their dentist but only 34.5% on interdental cleaning. Many studies have shown that the dentist is the main source of oral health information to her/his patients. As in the present study, a younger and middle-aged sample in Iran indicated that the most common oral health information source was the dentist (52.6%), followed by TV/radio, books/newspapers, family/friends and the internet, and only 1% had not obtained any relevant information [
24]. Partially dentate adults in Brazil obtained information about oral hygiene mainly from their dentist or undergraduate dental students (62.2%), 5.5% from the media, and 0.8% from relatives [
25]. Dental advice led to a higher possibility of having adequate oral health literacy among younger and middle-aged Brazilian immigrants in Canada [
27].
Forty-three per cent of the participants reported that their dentist had educated them on denture cleaning, and 51.9% on removing the dentures at night. Lower percentages were reported by middle-aged and older individuals in Brazil (22.5%) [
26] and Iran (39.6%) [
28] but were higher in Turkey (90%) [
29].
The findings in the present study revealed that many participants did not perform the recommended daily oral and denture hygiene practices [
12,
13,
14]. A positive finding was the combination of a toothbrush and fluoride toothpaste (95%). Similar findings in adult and older populations have been reported in other countries [
30,
31]. The use of fluoride toothpaste has expanded in the past decades, particularly in developed countries. It is a major contributor to decay control and has been included in the list of essential medicines by WHO [
4]. Electric toothbrushes were used by a very small number of participants (3%). Although electric toothbrushes seem to be equally or even more effective in dental plaque removal compared to conventional ones, further studies are needed to examine their applicability and affordability in older individuals [
32].
Regarding toothbrushing frequency, 42% of the participants brushed their teeth at least twice a day compared to 31% in a previous study among older adults in the same geographical area [
33], which is considered significant progress. However, there is large variability in relevant findings among countries [
30,
31,
34,
35].
Only 36% per cent of the participants regularly cleaned the interdental areas with dental floss and/or interdental brushes. Although there is a large variation in the frequency of interdental cleaning between studies, rates are significantly lower compared to toothbrushing [
30,
31]. It should be noted that only 21% of the study participants combined toothbrushing with fluoride toothpaste at least twice a day and regular interdental cleaning, and these habits have been associated with related instructions from their dentist.
Many participants (35%) used mouth rinses daily or occasionally, but only 16.2% after dental advice, as it is highly recommended to control potential side effects. Other information sources such as the media, relatives and friends and other healthcare workers played an important role in promoting this habit. A systematic review of randomised clinical trials demonstrated the wide use of mouth rinses, especially those which contain chlorhexidine, fluorides and essential oils, in the older population [
36]. These findings clearly indicate that more emphasis is needed on educating non-dental healthcare providers and the public about the proper use of various mouth rinses.
Mechanical brushing with toothpaste was the most common denture hygiene practice (55.4%) despite the existing recommendations to avoid toothpaste. Previous studies among denture wearers in American, Asian and European countries also reported mechanical brushing alone (36.5–100%) or with toothpaste (29.2–88.9%) as the most prevalent denture cleaning method [
26,
28,
34,
37,
38,
39,
40,
41,
42,
43]. However, only 54% of the study participants cleaned their dentures at least twice a day, and only 22.2% used denture cleansing tablets as recommended [
12,
13,
14].
Less than 70% of denture wearers removed their dentures at night, and the main contributor to this practice was previous dental advice. However, few denture wearers across the globe (23.6–58.5%) remove their dentures at night [
26,
28,
37,
38,
39,
40,
41,
44,
45], although proper hygiene and nocturnal removal of dentures can reduce the incidence of aspiration pneumonia, a leading cause of death from infection among frail older persons [
9,
46,
47,
48].
Although the dentist was the main source of information about the use of denture adhesives, the media, relatives and friends also played a significant role. Denture adhesives support the quality of life of denture wearers [
49], but their use should be based on professional advice [
50].
Women reported better daily oral hygiene practices compared to men but not to a statistically significant level. Several previous studies in adult and older populations have associated female gender with higher level of oral health literacy and better toothbrushing and denture hygiene habits [
24,
41,
51,
52]. Participants with more than six years of education were twice as likely to brush their teeth at least twice a day. Lower educational level has been frequently reported as a significant predictor of poorer oral health literacy among middle-aged and older people [
26,
30,
51,
53,
54,
55,
56,
57]. Last dental visit was another independent predictor for increased toothbrushing frequency. However, only 45.3% of the dentate participants had visited the dentist in the past 12 months, and this percentage decreased to 39.3% in denture wearers.
Many participants did not recall having received detailed information about dental and denture care practices from any source. This score was 35.3% for toothbrushing, 59% for interdental cleaning, and 44.4% for daily denture hygiene. Patients tend to forget oral health instructions provided by their dentists [
58], and this may explain both a large number of those with poor reported oral hygiene practices as well as those who reported that they had not received any information from any source. Almost one-third of a Brazilian sample of adults up to 64 years old also reported that they did not have any access to oral health information [
59].
Older individuals face various degrees of declines in intrinsic capacities, such as cognitive and visual impairment, hearing loss and limited mobility [
60], which may limit access to the dentist, their understanding of the provided instructions and the actual daily hygiene practices. The type of information from the dentist may have a significant effect on the level of denture cleaning [
29]. Those who had obtained both written and verbal advice had the highest level of denture cleaning, followed by those who were informed only verbally or only in written [
29]. It seems that the use of multiple oral health information sources may improve oral hygiene practices. Moreover, easy-to-read oral health education material enriched oral health literacy among older adults [
61]. Access to digital technology may help even those with limited access to dental offices, as web-based oral health promotion programmes for older adults have been shown to improve oral health knowledge, attitudes and self-efficacy [
62]. However, this requires digital literacy promotion programmes for older people.
Dental practitioners should improve their communication skills with older adults [
63] and provide comprehensive oral health information adapted to individual levels of capacity. Moreover, non-dental care providers who play an important role in oral hygiene counselling of older adults and their carers should receive appropriate oral health education and training [
18]. Finally, effective policies are needed to improve the oral health literacy of the public for self-care and care of others [
18].
Study Limitations
Study participants belonged to a functionally independent urban dental school sample, restricting the generalisation of the findings to functionally dependent older population groups and those living in rural areas. Also, there is a high possibility of recall bias as patients may have forgotten their dentist providing information about dental and denture hygiene. In addition, the reported oral hygiene practices, dental visitation habits and sources of oral health information may not correspond completely to reality since some participants may have adapted their answers to satisfy the investigators (Hawthorne effect). Finally, the clinical examination included only the number of natural teeth and the presence of the dentures without investigating other oral health indicators.