Effectiveness of message framing to improve oral health behaviors and dental plaque among pregnant women

Oral health is taken into account as an important factor in determining individuals’ quality of life. In this respect, pregnancy can have its own significant effects on oral health. Therefore, health messages can play an important role in motivating people to improve their health-related behaviors. Accordingly, the purpose of the present study was to investigate the impact of message framing on oral health-related behaviors as well as dental plaque among pregnant women. This quasi-experimental study was conducted on a total number of 108 pregnant women in the city of Izeh, Iran in 2017. To this end, the participants were randomly divided into three groups; gain-framed, loss-framed and control group. The research instrument included a demographic characteristics questionnaire along with the constructs of knowledge, attitude, behavioral intention, self-efficacy, performance, and dental plaque index derived from previous studies. Moreover, gain- and loss-framed messages were sent to the intervention groups via cell phones but the control group did not receive any messages in this regard. The participants’ dental plaque was also examined within two steps by a dentist. The significance level of the tests was considered by p<0.05. The results revealed the mean scores of behavioral intention, and self-efficacy had significantly increased in the gain- and loss-framed intervention groups (p<0.001) as compared to control group; but no significant difference was observed in the control group (knowledge, p=0.135; attitude, p= 0.166; behavioral intention, p=0.2; self-efficacy, p=0.37). The rising trend in the mean score of the behaviors in the intervention groups was significantly higher than in the control

group (p<0.001). The percentage of dental plaque in the gain-and loss-framed intervention groups also showed a significant decrease compared with that in the control group (p<0.001).

Conclusion
The results revealed message framing could improve knowledge, attitude, behavioral intention, self-efficacy, and dental plaque among pregnant women. Also, the gain-framed oral health messages could more improve the study variables, although such a difference was not significant.

Background
The World Health Organization (WHO) introduces oral health as a necessity for general health throughout life [1]. Moreover, oral health is considered as an important factor in determining individuals' quality of life in various physical, mental, and socioeconomic aspects [1,2]. With regard to increased communications as well as various social situations among people in today's society, the inevitability of adherence to oral health is felt much more than ever before [3[. The burden of oral diseases has also grown by 20% from 1990 to 2010 globally [4]. In this resepct, the results of nation-wide studies have similarly indicated that oral health in Iran's society is at a moderate level, according to the WHO report in 2000 [2]. Many adults around the world are also at the risk of dental caries and periodontal diseases [5,6], caused by the activity of bacteria in dental plaque (7]. To improve oral health status in adults, prevention programs need to be performed before birth [8]. Physiological changes in the mouth occurring during pregnancy have been similarly confirmed [9]. It should be noted that pregnancy is a very important event in a woman's life which has high potential to affect her and her child's health status [10].
Hormonal changes and nutritional conditions can also make pregnant women susceptible to gum diseases and dental caries [1,11,12]. Early morning nausea and vomiting, too much consumption of sugar and other foodstuff, as well as less use of toothbrush and floss can ultimately lead to the formation of microbial plaque and dental caries [13].
Periodontal diseases are also associated with antenatal complications and childbirth such as early birth, low birth weight, limited intrauterine growth, or small embryos for its gestational age [11,12,14,17]. It should be further noted that pregnant women can suffer from dental caries by 2.9 times than non-pregnant ones [18]. Despite the fact that the risk of oral diseases during pregnancy is high, pregnant women use less dental care and ignore oral hygiene than the general population. Based on surveys conducted around the world, it has been estimated that 58-65% of pregnant women are not committed to oral care [1,19,21]. In this regard, the results of the study by Bayat et al. on pregnant women in the city of Hamadan, Iran, showed that 68% of such individuals were brushing their teeth once a day, and only 11.8% of them were doing so after each mealtime [13]. In an investigaiton by Moawed et al., pregnant women reported several common factors hindering their access to oral care including lack of information about oral health, insufficient time, and fear of dental treatments; indicating that these individuals were in need of much more information on oral care [22]. Therefore, oral health education can be taken into account as one of the most important and critical factors in preventing plaque formation as well as occurrence of dental diseases [23]. However, the effectiveness of a health education program depends largely on the use of an appropriate educational theory [24]. Prospect Theory in this field is known as one of the decision-making theories under conditions of uncertainty. Accordingly, individuals break away from risks in conditions with a wide range of gains, but when they are exposed to conditions with a wide range of losses, they seek for risks to some degree [25,29]. According to this theory, completely similar information about decisions under uncertain conditions can be framed and presented in one of two ways: potential gains and potential losses [26,29] . The message framing approach used to deliver health promotion messages based on the Prospect Theory was developed by Kahneman and Tversky in 1979 [30]. Salvey and Rutmann have also put forth two hypotheses for message framing. The first hypothesis is that lossframed messages are more effective for individuals influenced by a disease when the purpose is to diagnose it and the second hypothesis is that gain-framed messages are endowed with more effectiveness for those who are involved in a behavior with definite consequences in occasions when the purpose is to prevent a disease [27]. The findings of a study conducted in the United States also revealed that a large percentage of adults (92%) owned a cell phnoe allowing the distribution of information through text messages and it could be also used to send messages related to health threats [31]. Therefore, the issue of effectiveness of health-realted message framing on individuals in society regarding more favorable attitudes makes the intention to adopt such health-realted behaviors a necessity and it is of utmost importance to examine such differences [20].
Following decades of research in message framing, there is still no clear answer on whether or not emphasis on positive or negative results will be effective in a convincing message [32].
Accordingly, the purpose of this study was to investigate the effectiveness of message framing on oral health-related behaviors and also its impact on dental plaque index among pregnant women.

Methods
This study was a quasi-experimental intervention carried out in Physiologic Birth and Counseling Center the city of Izeh , located in the southwest of Iran, From November 2017 to February 2018.

Participants
The study population included pregnant women referring to the Center in Izeh to attend maternity antenatal training classes. The women were selected using non-probabilty convenience sampling method. Then, they were divided into three groups; gain-framed intervention group, loss-framed intervention group, and control group using block randomization technique via 6 blocks. Allocating subjects to the study groups (intervention and control) was done using six blocks. This was done with WinPepi11.0 software. This software generates random groups. In each block, 3 subjects were from the control group and 3 subjects were from the intervention group, which was arranged randomly. Finally, 16 blocks were used. The steps of using the software listed were as follows: Aetcetera, Randomization (Random allocation)Balanced Randomization, Successive blocks. To determine the sample, the formula for comparing the means was used in which α=0.01 and β=0.1 and x 1 =0.07, x 2 =0.09, s 1 =0.123, s 2 =0.147, based on the results of similar previous studies [6].
The sample size was considered to be three groups of 36, and a total number of 108 individuals were estimated.

Inclusion criteria
The inclusion criteria in this study were being able to read and write, access to cell phones, willingness to participate in the study, not having high risk pregnancy as diagnosed by their midviwes, not having an underlying disease (cardiovascular disease, autoimmune disease, cancer, diabetes, etc.), gestational age of 16 to 28 weeks, as well as age ranges between 18 and 35 years.

Measures
Demographic data sheet The first part of the questionnaire included demographic characteristics as well as previous pregnancy history which was comprised of 14 items (maternal age, husband's age, duration of marriage, gestational age, maternal occupation, husband's occupation, coverage of healthcare insurance services, maternal level of education, husband's level of education, previous pregnancy history, maternal ethnicity, monthly houshold income, family size, and place of residence).

Questionnaire
The second part of the questionnaire consisted of the constructs of knowledge about general health and oral health and hygiene during pregnancy, attitude, behavioral intention, self-efficacy, and performance in mothers concerning oral health. The construct of knowledge with 14 items had been developed about the prevention of oral problems (additional file 1) and was scored as follows; a correct answer was rated 1 and an incorrect answer was assigned with 0. The construct of attitude consisted of 10 items, the behavioral intention contains 6 items, and self-efficacy was comprised of 9 items that had been desigend based on a 5-point Likert-type scale. In terms of scoring, positive items were rated 1, 2, 3, 4, and 5 for totally disagree, disagree, neutral, agree, and totally agree; respectively. This scoring was also done in reverse for negative items which had

Validity and reliability
In order to determine the scientific validity of the method, content validity and face validity were employed. Therefore, the opinions of 10 professors in this field were elicited.
After summarizing expert opinions, content validity ratio and content validity index were calculated. Using the cut-off point in Lawshe's table, comparisons showed that the obtained number was greater than that specified in the table (0.99) [33]. After summarizing expert opinions, content validity ratio and content validity index were calculated. The content validity index was found to be perfect (CVI= 1). To measure its face validity, the questionnaire was submitted to 10 pregnant women with conditions similar to those of the target group to have their impression of the importance of the questionnaire items via a 5-point Likert-type scale including absolutely important, important, moderately important, slightly improtant, and absolutely not important. The face validity of the questionnire was approved (impact score 4.5).
The reliability of the questionnaire was also confirmed. The scientific reliability of this research instrument was determined by the researcher using test-retest method. To this end; in a pilot study, the questionnare was given to 10 pregnant women meeting the inclusion criteria within a 14-day interval and it was recompleted by them after two weeks. The Pearson correlation coefficients for the constructs of attitude, behavioral intention, self-efficacy, and performance were by 0.89, 0.89, 0.91, 1; respectively. For the knowledge alpha Cronbach's was used to assess internal consistency, the result found to be satisfactory, 0.80.

Blinding
The validity of the messages was approved through a message validity checklist. In order to ensure no information bias, the study design was selected as a double-blind type in such a way that the participants were kept unaware of the type of the received messages (gain-and loss-framed ones), and also the assessor of the dental plaque (the dentist) was kept uninformed of the allocation of the given individuals into the groups.

Intervention
Two cell phone numbers were taken from pregnant women for the delivey of messages and follow-up. Thereafter, a positive message was sent to the gain-framed intervention group each day, a negative message was sent to the loss-framed one, and no messages were sent to the control group. The desired intervention was composed of 30 identical messages in terms of concept, but different considering the frame which was associated with advantages and disadvantages of not using toothbrushes, dental flosses, and mouthwashes; developed by examining and referring to texts and using message design principles [35]. Then, the given intervention was sent in the form of SMS as a message per day to the individuals in gain-and loss-framed intervention groups, but the control group did not receive any messages. For example, the gain-framed intervention group recieved the message of "If you floss every day, you will have a beautiful smile" while the following message was sent to the loss-framed intervention group; "If you do not floss every day, you may be embarrassed with your smile" [36]. Validity and reliability of messages was confirmed using validity checklist of messages [27], The pregnant women were also asked to ensure researchers of receiving the messages through replying by a blank message sent to them. If the researcher did not receive a message from pregnant women after 3 days [37], they would call them or sent them educational messgaes through other cell phone numbers. Eight weeks after sending the messages, the post-test questionnaire was completed by the three study groups in person.

Oral health examinations
The examination of the pregnant women's teeth was also fulfilled by a dentist and according to the required standards and then the percentage of dental plaque was measured using a dental plaque index (i.e: NPI) [21,34]. The given index was a valid tool which had been utilized by different researchers. The measurements were performed using disclosing tablets along with plaque measurement chart. In order to calculate the accuracy of the measurment through the dental plaque index by the dentist, the dental plaque was measured shortly after the main measurement for 10 participants in the study.
Internal consistency was also performed and approved using Cronbach's alpha coefficient (0.9).

Data analysis
Results were analyzed in SPSS 23.0 using dependent t-test and Chi-square analysis. The Kolmogorov Smirnov test was employed to determine the normality of data distribution.
Analysis of variance (ANOVA) or its non-parametric equivalent was also utilized to compare quantitative vlaues between the three groups. The relationship between qualitative variables was similarly measured through test. To compare attitude, behavioral intention, self-efficacy, and performance of the two intervention groups, the analysis of covariance (ANCOVA) was used considering the initial values. The significance level was considered at 0.05.

Ethics
All participants were informed about the study and confidentiality protocols.

Results
The mean age of the participants in this study was 27.4±4.37 years with a minimum age of 18 and a maximum age of 35. The homogeneity of the groups in terms the demographic characteristics affecting the study results including maternal age, gestational age, maternal occupation, maternal level of education, previous pregnancy history, maternal ethnicity, monthly household income, place of residence, and coverage of healthcare insurance were illustrated in Tables 1 and 2. The mean and standard deviation of the variables were similar at the beginning of the study and no significant difference was observed in all groups. Moreover, the normality of the groups was measured using Kolmogrov-Smirnov test and, if necessary, ANOVA and Chi-square test with a significant level of p<0.05 were used. The mean score of the constructs of knowledge, attitude, behavioral intention, self-efficacy, and performance in the intervention and control groups were presented in Table 3.
In this study, the mean difference of knowledge before and after intervention in the gainframed intervention group, loss-framed intervention group, and control group were reproted by 6.06, 5.72, and 0.38; respectively. There was also a statistically significant difference in the mean score of knowledge in the intervention groups compared with that of the control group (p<0.001). Despite the fact that the ascending trend in the mean score of knowledge in the gain-framed intervention group was higher than that of the lossframed one, it was not statistically significant.
Based on the results of ANOVA, the mean score of attitude in preganant women regarding oral-dental care before the educational intervention in the intervention and control groups did not show a significant difference. However, following intervention, the mean scores of attitude in individuals in the gain-and loss-framed intervention groups were respectively by 44.4 and 42.44, which were significantly higher than that of the control group (p<0.001). Although this increase was higher in the gain-framed intervention group than the loss-framed one, it was not statistically significant (p=0.83).
Furthermore, the findings of this study showed that the mean score of behavioral intention and self-efficacy in the intervention groups had significantly augmented after the intervention compared with that of the control group (p<0.001), but there was no significant difference between the two intervention groups. The results also revealed that the maximum decrease in dental plaque index was related to pregnant women in the gainframed intervention group; however, no significant difference was observed (p=0.87). On the other hand, there was a significant difference between the mean scores of dental plaque in the intervention groups and the control group (p<0.001). Based on the results of ANOVA, the amounts of decline in the dental plaque index in individuals in the gainframed intervention group, the loss-framed intervention group, and the control group were by 16.47%, 15.07%, and 2.16%; respectively.
In this study, the mean score of maternal performance concerning oral care before the educational intervention in both gain-and loss-framed intervention groups implied no significant difference. However, a significant increase was observed in the mean scores of the gain-and loss-framed groups after intervention compared with that of the control group (p<0.001) while no satistically significant difference was reported between the intervention groups (p=0.87).

Discussion
The purpose of the present study was to invetigate the effect of an education program based on message framing on oral health-related behaviors among pregnant women in the city of Izeh, Iran. To control the intervening variables, to ensure that the study groups were homogeneous in terms of demographic characteristics, and also to verify the accuracy of the findings in this study.
The results of this study suggested that framed messages could further improve the mean score of knowledge in both intervention groups compared with that of the control group.
Comparing the mean score of knowledge of oral health and hygiene showed that gainframed messages were more effective than loss-framed ones although no statistically significant difference was observed in this respect. Considering the control group, the mean score of knowledge increased at the end of the study but it was not reported significant.
In this regard, the findings of the study by Ghajari et al. showed that education based on message framing could improve students' knowledge in both gain-and loss-framed intervention groups compared with the control group [38]. The results of the study by Besides, the findings of the present study showed that the mean score of attitude in both intervention groups had increased compared with that of the control group. However, there was no statistically significant difference between the gain-and loss-framed intervention groups. Considering the control group, the mean score of attitude also increased at the end of the study, but it was not significant. A significant rising trend was reproted in the mean score of behavioral intention in both intervention groups compared with that of the control group. Comparing the mean score of behavioral intention in terms of oral health, it seemed that gain-framed messages were more effective than loss-framed ones, while no statistically significant difference was observed between gain-and loss-framed intervention groups in this regard.
The results of the study by Pakpour et al. suggested that students who had received lossframed messages were endowed with stronger tendency towards using toothbrush and floss compared with those who had received gain-frmaed messages [29]. This difference might be due to the discrepancy in the target groups. On the other hand, in the study by Pakpour et al., the impact of cultural conditions on the outcomes were highlighted, which could be regarded as an important component. Moreover, the results of the study by Uskul et al. revealed that British white participants who had stronger intentions had been conviced by gain-framed messgaes, while participants in East Asia, who were endowed with preventive intentions, had been encouraged by loss-framed messages [29,39]. Considering the mean score of self-efficacy, a significant increase was observed in both loss-and gain-framed intervention groups compared with the control one. Comparing the improved mean score of self-efficacy in terms of oral health, it seemed that gain-framed messages were more effective than loss-framed ones, while no statistically significant difference was reported between both intervention groups in this regard.
The results of the study by Merdasi et al. indicated that message framing could enhance self-efficacy of breastfeeding in nulliparous women in gain-and loss-framed intervention groups, although no statistically significant difference was reported between these intervention groups [27].While the mean score of performance in gain-and loss-frmaed groups showed a significant increase compared with that of the control group, there was no statistically significant difference between both intervention groups.
It should be noted that oral health-related behaviors such as brushing the teeth and flossing them have been recognized as two-state behaviors (i.e. behaviors targeting early diagnosis or behaviors targeting dental caries) [29]. Moreover, individuals' motives could play a role in regulating numerous behaviors, so considring such motives could be effective in determining how oral health-related messages to various people could be designed. Based on the Theory of Motivation, individuals who were approach-oriented could change their behaviors through a gain-framed oral health message and those who were avoidance-oreinted could adhere to loss-framed ones [40]. Therefore, various outcomes are expected in different studies adopting preventive or diagnostic approaches and also employing target groups with diverse motivational approaches.
The study by Gallagher et al. revealed that gain-framed messages had much more capacity than loss-framed ones to encourage preventive health-related behaviors particularly to prevent skin cancer, to quit smoking, and to perform physcial activities [41] which was consistent with the results of the present study, although they were not significant. Furthermore, Schneider et al. reiterated that loss-framed messages had more impacts on accpetance and completion of mammography [42].
Distance learning can be effective because of the elimination of spatial and temporal constraints, and consequently establishment of an effective relationship with patients [27,43]. In this resepct, the study by Gharaati et al. emphasized these results. The findings of this study also demonstrated a significant increase in the mean scores of knowledge, attitude, and self-care behaviors in the intervention group following the fulfillment of the intervention, but no significant difference was observed in the control group [43]. The results of the study by Haghani et al. similarly indicated the effectiveness of messagebased education method in providing antenatal education [44]. Naderi et al. also concluded that use of cell phones could have a significant impact on students' metacognitive self-regulation as well as their attitudes towards cell phone-assisted learning [45].
Consideirng the decline in dental plaque, the examination of the study data showed that gain-framed messages were more effective than loss-framed ones. However, such a difference was not statistically significant between the two intervention groups. The percentage of dental plaque in the intervention group (gain-framed and loss-framed) and also the control group had also decreased. Moreover, there was a significant difference between the intervention groups compared with the control one. As a whole, reduced dental plaque in this study confirmed the improvement of pregnant women's performance.
As well, Lafzi et al. reproted that a significant decrease had occurred in the dental plaque index from 72% to 38% in the intervention group following two-month education which was in line with the findings of the present study. In the study by Shamsi et al., the mean difference of dental plaque index in the intervention and the control groups were significantly different. Moreover, the results of this study showed that the mean score of the intervention group had significantly increased compared with that of the control group following educational intervention. This rising trend in pregnant women's performance consequently led to improved oral health and better dental plaqua indices in individuals in the intervention group [21]. Considering no statitistically significant difference between two types of framed messages in the educational intervention, other reasons except the same effectiveness of these two types of frames could be highlighted. So; the messages could be more effective if their presentation was sequantial and consequently the finidings would be different. On the other hand, the inappropriate time of intervention could be taken into account as one of the factors shaping the effectiveness of the delivered messages. Moreover, the non-significance of the expected results could be because of no deep, accurate, and effective attention to health-related messages.
In most cases, there was much more increase in the outcomes of the study including the mean score of knowledge, behavioral intention, and self-efficiacy associated with oral health after sending messages to the gain-framed group compared with that of lossframed and control goups. Furthermore, the percentage of dental plaque in the gainframed group was much more than that of loss-framed and control groups although the results were not statistically significant. These findings were in agreement with the results of related investigations [20]. Thus, it was concluded that development of theory-based oral health programs could be effective and also efficiant in terms of providing education to pregnant women in this domain.

Limitations
One of the limitations of the present study was that the findings could not be generalized to the entire community of preganant women, given the further visits by such individuals residing in urban areas compared with those with limited visits in rural ones due to long distance and other problems.

Conclusion
The results of the present study showed that framed health education messages could enhance knowledge, attitude, behavioral intention, self-efficacy, and performance among pregnant women and also reduce dental plaque in the intervention groups. However, no significant diffrence was observed in terms of the effectiveness of the loss-or gain-framed messages in the constructs associated with oral health in pregant women.

Authors' contributions
The authors' responsibilities were as follows: MA were supervisor of the study. MA designed the study and questionnaire and also drafted the manuscript. BCH and MD conducted the study. A-BH helped study implementation. All authors contributed the design and data analysis and assisted in the preparation of the final version of the manuscript. All authors approved the final version of the manuscript.  · Derived from chi-square  Questionnire.Divdaroc.doc