The results of this study provide initial evidence of the benefits of an oral health promotion program for improving the oral hygiene status of patients with SMI. Moreover, patients with SMI may enjoy improvement in oral health knowledge, attitude and behavior after just a short period of group education. To the best of our knowledge, this is the first report using both group and individual components of an oral health intervention to achieve oral hygiene improvement in patients with SMI. The strengths of the study included its randomized controlled study design, that the examiner was blinded to group assignments, and there was an adequate sample size and a low drop-out rate.
To cope with the universally poor oral health conditions among patients with SMI, multiple levels of strategies have been proposed, consisting of reorganization of dental services [28], increased accessibility to dental care [13], regular dental check-ups [21,29], undertaking aggressive preventive education programs [30], and improving oral health hygiene by means of educational intervention [31]. However, psychiatric patients are known to suffer from a variety of so-called negative symptoms, such as apathy and loss of drive, which would impede self-care and lead to neglect of oral hygiene [13]. Some cognitive-behavioral approaches have been tried. In 2 studies by Almomani et al., oral health education, a reminder system, provision of a mechanical toothbrush [23] and motivational interviewing [24] were used. In a study by Mun et al., an oral healthcare education program using video and brochures was provided to participants [25]. In the current study, however, we used a combination of cognitive-behavioral methods and a group format.
With regard to experiences in applying general lifestyle interventions to persons with SMI, the literature has indicated that single-component programs are less effective than those employing multiple components [32,33]. Moreover, group sessions are potentially cost-effective and may be beneficial in reducing social isolation in this population [34]. Mental illness can compromise a person’s ability to make decisions in daily life, and so social support and peer support are essential to learning about and practicing oral health programs tailored for those patients [35]. In chronic psychiatric wards, as with our study setting, education, reminder systems, and behavioral modification measures are employed on a group basis, and we postulated that the group effect could have a motivational effect on psychiatric inpatients to encourage them to adhere to oral health programs and ultimately improve their oral hygiene.
In Japan, Yoshii et al. conducted a study to determine the effect of an educational program on improving oral health self-care. The one-time 30-min oral hygiene education presentation resulted in an improvement in the use of fluoride toothpaste and in the daily use of interdental brushes or floss, even 6 months after the intervention [31]. However, the habit of tooth-brushing or visiting the dentist remained unchanged after the educational program. In our study, the group education program was applied repeatedly, 5 times in all, and was combined with a behavioral change strategy. The results of the Yoshii et al study indicated that education alone might not bring sustained change to the oral hygiene habits of patients with SMI, and that a combination of both cognitive and behavioral therapeutic interventions are needed for persons with SMI. Furthermore, to achieve sustained oral health hygiene behavioral change, repeated educational sessions should be provided, instead of only a few interventions.
Strategies to improve the oral health of persons with SMI in the community would be different from those applied in psychiatric wards. Preventive and treatment programs for oral health should be tailored to meet the individual needs of patients based on their diagnoses, severity of mental illness and cognitive functions [36]. It has been suggested that cognitive function may play a crucial role in dentist-seeking behavior among patients with SMI [21]. Oral hygiene habits, easily neglected by patients with SMI, should be promoted by not just education, but more proper measures, such as behavioral modification, to deal with the negative symptoms and poor cognitive functions of those patients.
In the current study, individual behavioral modification was encouraged by token reinforcement contingent on tooth-brushing behavior or attendance at group sessions. In the literature on healthy living interventions, monetary payment or tokens were given to psychiatric patients who abstained from smoking [37,38] or lost weight [9]. Our results are consistent with previous studies that demonstrated the effectiveness of contingent management approaches in reinforcing healthy behavioral change in persons with SMI. However, the generalizability of contingency behavioral approaches might not be replicable in routine health care settings, since there is a high degree of control of the environment in institutions. Other individual-level approaches such as the use of praise and disapproval contingent on targeted behavioral change might be considered unethical and possibly iatrogenic [39].
Our study result is consistent with that of Almomani et al., in that persons with mental illness had greater improvement in oral health knowledge after the education sessions [24]. Previous studies suggest that poor oral hygiene may reflect a lack of knowledge or the lack of a rationale for treatment [40,41]. Therefore, knowledge acquisition through education may be an important step to take in changing the oral self-care behavior of those patients. In our study, only an instructive educational program was used with the participants. Peteuil et al. proposed a therapeutic educational program that used focus group interactions to achieve better oral health knowledge and oral health-related quality of life [42]. To date, there is no consensus on which educational intervention is better for persons with SMI. Further studies are needed to determine the most effective and convenient type of oral health education for these patients.
Most participants in the intervention group changed their oral health behavior, especially in terms of tooth-brushing. However, there was no significant difference in the consumption of sugar-added beverages and in dentist-visiting in both groups. A patient preference for snacks or sweet beverages might reflect their worse general health habits that are not easily changed by a few educational sessions. Additional efforts through motivational interviewing or environmental change (such as in supplying non-sweetened beverages or healthy snacks) should be taken to achieve better oral hygiene in patients with mental illness.
This was a short-term experimental study in which we observed improvements in dental plaque in those patients receiving the intervention only. Dental plaque, however, is only a surrogate end-point for our concern regarding this disadvantaged population, which is reducing the prevalence of caries and periodontal diseases. Nevertheless, there is no doubt that this is the first step we should take. Persons with SMI are susceptible to dental diseases for many reasons, including poor oral hygiene habits, reduced motivation for personal care, high consumption of sugary food or beverages, fear of dental treatment, neglect of oral health, difficulty accessing dental care facilities and reduced protective saliva due to the side effect of psychiatric medications [13,14]. By improving the oral hygiene of patients with SMI, encouraging regular dental check-ups, increasing the accessibility of dental care, and increasing an awareness of the importance of oral health in patients and staff, as well, we can achieve better overall oral health and subsequently improve the general health of psychiatric patients.
The results of the present study should be interpreted with caution, in light of some limitations. First, the study subjects were psychiatric inpatients; therefore, the intervention measures taken to improve the oral health of persons with SMI might not be applicable to patients in the community. Further studies with a focus on designing appropriate interventions to achieve better oral health among patients in a variety of settings and with heterogeneous group characteristics should be conducted. Second, we noticed that dental plaque also improved among individuals in the control group. Given that the participants were not blinded to the group assignments, we cannot rule out the possibility of an extra-effort effect arising in the control group. But even so, the effect size of the intervention is still significantly large enough to substantiate the validity of the results. Third, the study intervention consisted of a composite of the elements of behavioral therapy, education and a group approach, so we are not certain which one was the key factor in reducing dental plaque. Finally, we did not measure the sustained effect of the oral health promotion program after the trial was finished. It is likely that further booster sessions are needed to help patients with SMI maintain good oral hygiene habits in the long term.