A randomised controlled trial of an educational intervention to promote Oral and dental health of Patients with Type 2 Diabetes Mellitus

Diabetes is the most prevalent disease resulted from metabolic disorders. This study aimed to investigate the effect of training based on health belief model on oral hygiene-related behaviors in patients with type 2 diabetes mellitus. This study was conducted as a quasi-experimental research on 120 patients with type 2 diabetes referring to a diabetes clinic selected through systematic sampling, who were assigned to two groups of control (N=60) and intervention (N=60). The data collection tool was a valid and reliable questionnaire based on health belief model which was completed for both groups before the intervention. Then, the intervention group received 4 sessions of training based on health belief model in one month and the same questionnaire was completed again after 3 months and the obtained data were analyzed.

The only effective and efficient strategy for solving the problems related to oral hygiene is observing oral hygiene and prevention [7]. According to the report by the World Health Organization (WHO), health training is the best and the most effective way for ensuring the health of people in a society, considering the required human resources and high medical expenses [11].
According to the WHO, training is the basis of diabetes treatment. In fact, training has been recommended as a necessary component of enhanced diabetes control and studies have shown that training have been effective in diabetes control and treatment. According to these studies, appropriate training can decrease diabetes complications up to 80% [11][12]. Health belief model is one of the oldest models of behavior analysis, which has been used in various studies on hygiene-related behaviors including those among patients with type 2 diabetes mellitus (T2DM) [13]. Social psychologists developed this model in 1950s in order to predict the reasons of people's reluctance for participating in preventive hygiene-related behaviors [14].
In this model, patients with diabetes should first feel themselves vulnerable to oral problems and understand the seriousness of these complications. Then, in order to decrease these complications, they should understand the benefits of oral hygiene care, the barriers should be removed and the patients should be guided toward taking oral hygiene care through increasing their self-efficacy and capability and emphasizing the role of cues as internal and external triggers ( fig. 1).

Aims Of Research
The overall aim of this study is to design and evaluate an educational intervention to promote oral and dental hygiene-related behaviors in Patients with T2DM.

Methods
This study will be conducted and reported on the basis of Consolidated Standards of

Design and sample study
This study was a quasi-experimental research on 120 patients with diabetes referring to the Diabetes Clinic in the city of Kashan, Iran from 2017 to 2018. The population of the current study included all the diabetic patients admitted to Diabetes Clinic (N = 2500).
Considering equal to 5% and β to 0.1 using the following formula, the sample size was calculated as 58 participants in each group of control and intervention, which this number increased to 60 considering sample loss. So, the total sample size was 120.
Out of the patients having medical records in the clinic, 120 patients were selected through systematic sampling and were randomly (every other person) assigned to two 60member groups: control and intervention.
Randomization was achieved using sealed numbered envelopes developed from a random number generator. A research assistant who was not involved in the recruitment of participants prepared the envelopes. Participants allocated to the control group (n = 60) received standard care. Participants assigned to the intervention group (n = 60) also received standard care plus the educational intervention based on HBM.
Tree months after the intervention, the posttest was conducted for both intervention and control groups to examine the effects of education on the primary and secondary outcomes. Based on the nature of the intervention in the current study, the instructor was not blinded to group assignment, but participants and statistical investigator were blinded to group assignment.
Inclusion criteria were having medical records in the Diabetes Clinic, being at the age range of 40-60 years, being illiterate, living in the city of Kashan, having no oral symptoms, having no history of radiotherapy and hemodialysis, not consuming medicines with complications such as dry mouth, not wearing dentures and signing informed consent form to participate in the study. Exclusion criteria were not being willing to participate in the study, moving from Kashan, not being continuously present in training sessions and being afflicted with any condition. Figure 2 shows a flow diagram of the participants during the study period.

Research tools
The primary outcomes of the current research include the construct of HBM (Perceived Susceptibility, severity, benefit, barrier, cues to action and self-efficacy). The secondary outcome was oral and dental health behavior's.
The data collection tool in this study was a valid and reliable researcher-made questionnaire consisting of questions on demographic information, awareness, constructs of the health belief model and performance in oral hygiene-related behaviors in patients with T2DM. The validity and reliability of this questionnaire was approved and it was completed before the training intervention and three month after the intervention by both control and intervention groups. In this tool, those questions with CVR score higher than 0.62 and CVI score higher than 0.79 were considered as appropriate and included in the study [15].
To verify its reliability, the questionnaire was given to 30 diabetes patients and its reliability was calculated as 0.866 using Cronbach's alpha. The validity of the questionnaire was also approved by three hygiene training experts, three internal diseases specialists, one endocrinologist, one dentist, and one expert having a PhD in epidemiology and one executive focal point in the National Program for Prevention and Control of Diabetes (NPPCD) of Iran after removing or modifying some of its statements.
The diabetes patients' awareness of oral care questionnaire consisted of 9 questions. The correct answer scored 1 and the wrong one scored 0 and the total score of awareness was calculated out of 9.
The questions of the model constructs were scored on a 5-point scale from strongly agree, agree, no idea, disagree and strongly disagree scoring 1 to 5. The lowest and highest scores in each part of questions of health belief model constructs was different due to the different number of the questions of each construct. So, the score of each dimension was calculated out of 5.
The performance questionnaire on oral hygiene-related behaviors also consisted of 10 questions. This questions of this questionnaire were scored on a 5-point scale of behavior evaluation from never, rarely, sometimes, often and always scoring from 0 to 4 and the scores in this part were reported out of 4.

Intervention
Before performing the training intervention and in pretest stage, the questionnaires were completed by both groups and entered the computer to be used for determining the training needs and the constructs to be presented in training sessions. Then, according to the health belief model and based on the results of the needs analysis, the training program was prepared for four 120-minute sessions in one month targeted at the intervention group. The materials were presented in the sessions through lectures, question and answer, slide presentation, pamphlets and booklets to benefit all the time in class and make the training available for further study by the patients.
In the training intervention sessions, awareness of diabetes patients was emphasized aiming at gaining an appropriate knowledge of diabetes and factors affecting deterioration and acceleration of oral complications; perceived susceptibility and severity was touched by presenting the statistics on prevalence of oral problems resulted from diabetes and vulnerability of patients and severity of oral complications resulted from inappropriate blood sugar control and not performing oral hygiene-related behaviors. Also, the materials of these sessions emphasized on the benefits resulted from performing oral hygienerelated behaviors (reduced oral complications, reduced need to dentistry services and lower medical expenses, feeling of calmness and internal joy), identifying and removing perceived barriers on the way of performing oral hygiene-related behaviors (unawareness, bodily weakness, fatigue, feeling bored, etc.) external triggers affecting performing oral hygiene-related behaviors (including physicians, diabetes clinic nurses, family members, television, books and magazines in health centers, other diabetes patients) and the role of internal cues to action or triggers (motivation and internal calmness resulted from performing hygiene-related behaviors) were emphasized. Self-efficacy construct was emphasized by empowering the patients by the aim of facilitating performance of hygienerelated behaviors through presenting educational images on slides, practical training and distributing packages consisting of a toothbrush, a toothpaste and a floss threader among the patients and providing them with booklets and pamphlets. The performance dimension was approached through operationalizing oral hygiene-related behaviors by patients (brushing the teeth, using a floss threader, washing the tongue, massaging the gum, performing preventive behaviors and caring for probable oral complications of diabetes).
Three months after the training intervention, the questionnaire was given again to the both groups and the all 120 patients completed them.

Data Analysis
The data were analyzed using SPSS 20 through descriptive and inferential statistics (including independent t-test, paired t-test, Chi-square). The significance level was considered at 0.05. To investigate the normality of the data, Kolmogorov-Smirnov test was used and normal distribution of the data was obtained.

Ethical Considerations
Informed consent was obtained from all the participants (consent was written and no verbal).
All the procedures performed in the study involving human participants, were in accordance with the ethical standards.
The present study was approved by the Research Council of Arak University of Medical Sciences (Grant Number: 1711). Ethics committee approval code number is (IR.ARAKMU.REC.1395.444)). This study has been registered in Clinical Trial Registry with the code of IRCT2017050733847N1. After granting the consent of the patients, the aim of the study, the methodology, and the advantages and disadvantages of the study were explained to them. The participants were assured that they are not obliged to participate in the research and that they can leave it whenever they wish. They were also assured of the confidentiality of their information.

Results
In total, 120 patient with T2DM (control group = 60 and intervention = 60) were enrolled (from 2017 to 2018). Figure 2 shows a flow diagram of the participants during the study period.
The average age of the diabetes patients in the control and intervention groups was 53.264.46 and 53.484.38 years, respectively, which showed no significant difference based on the results of the independent t-test (p = 0.675). Table 1 shows the other demographic characteristics of the patients (Table 1).
There was no statistically significant difference between the two groups in terms of age, gender, income level, marital status, health insurance and educational qualifications.
The results showed that there was no significant difference between the intervention and the control groups in terms of health belief model constructs before the intervention.
Based on the results, before the intervention, the mean performance of the intervention and control groups were 2.16±0.71 and 2.28±0.76, respectively, with no statistically significant difference observed (p = 0.97). However, after the intervention, the mean performance score of the intervention group (3.25± 0.49) was significantly more than that of the control group (2.66± 0.56) (p = 0.001).
After the training interventions, independent t-test showed a significant difference in terms of awareness, susceptibility, severity, perceived benefits and barriers, self-efficacy and internal cues to action between the intervention and control groups. However, there was no significant difference between the two groups in terms of external cues to action (Table 2).

Discussion
Based on the results of this study, the training intervention caused a significant enhancement in oral hygiene-related behaviors in the intervention group compared to the control group. In fact, this enhanced behavior can be attributed to the training method based on the health belief model. The method of performing the training is itself a mechanism which can bring about a positive attitude toward the oral hygiene in diabetes patients.

The significant change in awareness after the intervention in the intervention group
showed the effect of the training intervention on enhancing the oral hygiene information related to oral hygiene in diabetes patients. These results were compatible with the results of many interventional studies such as those by Shabibi [16] and Tawfik [17] on the awareness of diabetes care. Also, the results of other studies are compatible with those of the present study [14,[18][19][20][21][22]. Therefore, preparing training and educational text and messages appropriate to the characteristics of the audience is one of the necessary principles of any training program as this study tried to present the training materials in a simplified way considering the age and literacy level of the learners.
In this study, perceived susceptibility of diabetes patients increased after the training intervention, while the average score of perceived susceptibility did not changed in the control group. This increase can be attributed to the training classes and question and answer and group discussions aiming at making the participants sensitive. This finding is compatible with those of Farahani et al. [23] on compliance with medicine regime in diabetes patients and other studies on nutritional and care taking behaviors of diabetes patients [24][25].
The results of this study indicate an increased perceived severity among patients compared to that perceived before the intervention, which is due to the effect of training classes, mentioning complications of the disease and presenting images on slides, distributing pamphlets and more interaction of patients as a result of group discussions.
However, this increase was not observed among the patients in the control group. This finding is compatible with the results of the studies related to increased perceived severity among diabetes patients and care aspects in nutrition and medicine regime and other care behavior in diabetes control [23][24][25][26][27].
In this study, the perceived barriers of the diabetes patients were lower compared to those before the intervention. Factors such as insufficient awareness of different kinds of oral healthcare and he way to do them, bodily weakness and physical diseases due to diabetes, high expenses of dentistry services and being afraid of dental treatments were identified as barriers and decreased through the training intervention, providing standard and programed solutions and strategies aiming at enhancing the oral hygiene, provision of tools required for oral hygiene and teaching required skills to the patients. The obtained results were compatible with those of other similar studies on the barriers perceived by diabetes patients regarding the diabetes healthcare [17,23,24,27,28].
The perceived benefits of patients increased after the training intervention as they understood how observing oral hygiene can decrease the risk of tooth decay, cardiac and digestive diseases and halitosis, keep the gums healthy and reduce the dentistry expenses. This finding was compatible with the similar interventional studies such as those by Sohrabivafa et al. [18], Sharifirad et al. [24] and other studies [17,23,27,28]. After the training intervention, self-efficacy construct increased by empowering the patients by the aim of facilitating performance of hygiene-related behaviors through presenting educational images on slides, practical training, dividing the behaviors into smaller parts and distributing packages consisting of a toothbrush, a toothpaste and a floss threader among the patients and providing them with booklets and pamphlets. Selfefficacy increased the capability of diabetes patients for controlling and managing their oral hygiene and this behavior was kept and performed continuously after the training intervention. This finding was compatible with those of Farahani et al. [23] and other studies on enhancing perceived self-efficacy of diabetes patients in diabetes care [17,24,[26][27][28][29].
The performance of oral hygiene-related behaviors by the patients increased in this study. This increase was due to operationalizing the oral hygiene-related behaviors (teaching the correct way of brushing the teeth, using a floss threader, washing the tongue, massaging the gum, performing preventive behaviors and caring for probable oral complications of diabetes). Successful control of oral health of diabetes patients mainly depends on performing hygiene-related behaviors by the patients [30]. In this study, the patients who stopped following the recommended oral hygiene-related behaviors mentioned lack of motivation, fatigue, laziness and high dentistry expenses as the reasons. Therefore, motivation and dentistry services with appropriate expenses are required for diabetes patients to perform the recommended oral hygiene-related behaviors correctly and continuously. The results of this study were compatible with those of the studies by Khani Jeihouni et al. investigating the health belief model constructs and tooth decay index in pregnant women [31], by Fril (2002) evaluating the effect of oral hygiene intervention among teenagers in Ireland [32] and by Shabibi investigating the application of health belief model to diabetes patients self-care [33].
One of the strengths of this study is that the training intervention on oral hygiene care for diabetes patients was designed based on the needs analysis (pre-test) and programed according to the health belief model constructs and the patients' behaviors were followed up three months after the training intervention.
Some limitations of this study could be the current research was performed in one geographical area in Iran, the generalizability of our results is decreased. Also, we followed up the patients for 3 months as the longer follow up may lead to more accurate outcomes. In addition, other factors that can affect the results such as the amount of stress and its effect on oral and dental health and especially gums were not measured in this study, and thus could be addressed in future studies.

Conclusion
The training intervention based on the health belief model lead to enhanced oral hygienerelated behaviors in patients with T2DM. It was found that diabetes patients' skills regarding the oral hygiene-related behaviors can be enhanced through training these patients and performing active follow-ups. This can finally lead to a reduction in incidence of oral complications in diabetes patients. Control, monitoring and training follow-ups are also recommended to be included in these training programs.

Supplementary Files
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