Illness perception in patients with dental caries: A co-relational study in Odisha
Introduction Dental caries is currently the most widespread chronic disease, as well as a major global public health challenge. The World Dental Federation (FDI) estimates that 60–90 % of schoolchildren and nearly 100 % of adults worldwide have experienced tooth decay in their lifetimes. According to Global Burden of Disease 2010 Study, dental caries is the most prevalent condition out of 291 diseases. A WHO International Collaborative Studies (ICCI,II) demonstrated that experience of dental caries is related to socio-behavioural factors, oral health-related behaviour and quality of life. Common determinants of oral health behaviour include intentions, self-efficacy, outcome expectancies, perceived susceptibility and perceived severity. Factors associated with dental caries encompass a dynamic interplay amongst behavioral factors like, personal characteristics, attitude, perception, and knowledge. Very often psychological and sociocultural factors attribute to variations in illness behaviour. The terms illness perceptions and illness cognitions are used to “describe a range of cognitive processes underlying attention, interpretation, and behaviour in response to illness-related information”. Illness perception provides not just an opportunity for early prevention, but also treatment and recovery plans. Illness-related self-regulatory behaviour includes self-assessment of health, which includes symptom perception, interpretation, and reporting. , The Common-Sense Model of Self-regulation (CSM) hypothesizes that illness cognitions function as a filter and interpretive scheme for illness information, which subsequently guides illness-related actions and behaviour. Five different logical themes or dimensions that characterize illness representations are cause, identity, consequences, timeline, and cure/controllability. In the year 1996, Illness Perceptions Questionnaire (IPQ) was developed to measure these five dimension of illness representation of an individual and was later revised in year 2002 (IPQ-Revised). Although, IPQ-Revised (IPQ-R) has been used to assess illness perception in the field of healthcare, very few studies have been carried out to evaluate the illness perception of dental caries. Hence, the present study was conducted to assess illness perception of patients having dental caries using IPQ-R in Odisha. 

Materials and Methods This descriptive co-relational study was conducted among 250 patients of S.C.B. Dental College and Hospital, Cuttack, Odisha, between September 2019 and December 2019. Ethical clearance for the study was obtained from the Institutional ethical committee (IEC/SCBDCH/046/2019). Patients with self-reported dental caries in at least one tooth and more than 18 years of age were eligible for the study. Eligible patients were then consecutively selected and recruited in the study. 2.1 Study sample A pilot study was first carried out among100 patients for assessing its feasibility, cross cultural validation of the questionnaire and determination of the correlation coefficient. Considering the correlation coefficient as 0.2, alpha 95 % and power to be 80 %, a sample size of 194 was calculated. After inflating the size by 20 % for nonresponse, the total sample size was decided to be 250. 2.2 Data collection tools Illness perception of the participants was collected using a self-administered structured schedule, followed by clinical oral examination. In addition to the demographic details of the participants, the schedule included a cross culturally validated IPQ-R tool in regional language, Odia, with three separate sections. In the first part, dental caries identity was assessed using 14 commonly experienced symptoms like toothache, tooth sensitivity, pain while taking hot and cold food, and so forth. The responses were recorded as yes/no. The second section assessed illness perception with seven dimensions, namely timeline acute/chronic (6 items), timeline cyclical (4 items), consequences (6 items), personal control (6 items), treatment control (5 items), illness coherence (5 items) and emotional representations (6 items). Altogether 38 items were presented with a five-point response scale: strongly disagree, disagree, neutral, agree, and strongly agree. The overall scores were obtained by summing up the scores of all items in each dimension. In the third part, 18 possible causes of dental caries were listed. Responses were recorded on a similar five-point scale. Dental caries was assessed using the scores of Caries Severity Index, by Tank Certrude and Storvick Clara in 1960. The extent of pulpal involvement was based on clinical and radiographic examinations. 2.3 Validation of the questionnaire For the cross-cultural validation, the questionnaire was first translated into Odia by two multilingual researchers individually. Translations were then compared to identify any discrepancies. Principal investigator mediated the discussion between two translators and facilitated coming up with a single version. Another bilingual researcher back-translated it into English and validated it with the original one. Two experts from the Department of Psychologyconsolidated the different versions of translations making them equivalent to source version. Effort was made to ensure that the translation carried the same meaning as the original version while also being sensitive to the nuances of Odia language. The translated version was pretested among 50 respondents. On evaluation of the reliability of both instruments (illness perception, CSI), with the exception of the personal control score (0.314) all Cronbach's α scores were acceptable or good (Timeline Acute/Chronic = 0.730, Timeline Cyclical = 0.542, Consequences = 0.723, Treatment Control = 0.675, illness Coherence = 0.504, Emotional Representation = 0.813). This suggested that our adaptation of the IPQ-R for dental caries would have adequate internal reliability if used among dental patients. 2.4 Study procedure Brief introduction was given to all participants about the study procedure, its objectives and its rationale. They were well informed about their right to withdraw from the study at any time. Participants were also assured that all personal details would be confidential and informed consent was taken. Data collection was performed through the self-administered schedule. Oral examinations were then carried out according to CSI using mouth mirror and explorer, by a single trained investigator ( ). 2.5 Statistical analysis Statistical Package for the Social Sciences (SPSS for Windows, version 23.0, SPSS Inc., Chicago, IL, USA) was used for further analysis. Spearman's correlation was applied for analysing the relationship between illness perceptions, CSI scores and socio-demographic variables. Multivariable analysis was conducted using binary logistic regression. The probabilities for entry and removal of variable in each step were set as 0.05 and 0.1, respectively. 

Study sample A pilot study was first carried out among100 patients for assessing its feasibility, cross cultural validation of the questionnaire and determination of the correlation coefficient. Considering the correlation coefficient as 0.2, alpha 95 % and power to be 80 %, a sample size of 194 was calculated. After inflating the size by 20 % for nonresponse, the total sample size was decided to be 250. 

Data collection tools Illness perception of the participants was collected using a self-administered structured schedule, followed by clinical oral examination. In addition to the demographic details of the participants, the schedule included a cross culturally validated IPQ-R tool in regional language, Odia, with three separate sections. In the first part, dental caries identity was assessed using 14 commonly experienced symptoms like toothache, tooth sensitivity, pain while taking hot and cold food, and so forth. The responses were recorded as yes/no. The second section assessed illness perception with seven dimensions, namely timeline acute/chronic (6 items), timeline cyclical (4 items), consequences (6 items), personal control (6 items), treatment control (5 items), illness coherence (5 items) and emotional representations (6 items). Altogether 38 items were presented with a five-point response scale: strongly disagree, disagree, neutral, agree, and strongly agree. The overall scores were obtained by summing up the scores of all items in each dimension. In the third part, 18 possible causes of dental caries were listed. Responses were recorded on a similar five-point scale. Dental caries was assessed using the scores of Caries Severity Index, by Tank Certrude and Storvick Clara in 1960. The extent of pulpal involvement was based on clinical and radiographic examinations. 

Validation of the questionnaire For the cross-cultural validation, the questionnaire was first translated into Odia by two multilingual researchers individually. Translations were then compared to identify any discrepancies. Principal investigator mediated the discussion between two translators and facilitated coming up with a single version. Another bilingual researcher back-translated it into English and validated it with the original one. Two experts from the Department of Psychologyconsolidated the different versions of translations making them equivalent to source version. Effort was made to ensure that the translation carried the same meaning as the original version while also being sensitive to the nuances of Odia language. The translated version was pretested among 50 respondents. On evaluation of the reliability of both instruments (illness perception, CSI), with the exception of the personal control score (0.314) all Cronbach's α scores were acceptable or good (Timeline Acute/Chronic = 0.730, Timeline Cyclical = 0.542, Consequences = 0.723, Treatment Control = 0.675, illness Coherence = 0.504, Emotional Representation = 0.813). This suggested that our adaptation of the IPQ-R for dental caries would have adequate internal reliability if used among dental patients. 

Study procedure Brief introduction was given to all participants about the study procedure, its objectives and its rationale. They were well informed about their right to withdraw from the study at any time. Participants were also assured that all personal details would be confidential and informed consent was taken. Data collection was performed through the self-administered schedule. Oral examinations were then carried out according to CSI using mouth mirror and explorer, by a single trained investigator ( ). 

Statistical analysis Statistical Package for the Social Sciences (SPSS for Windows, version 23.0, SPSS Inc., Chicago, IL, USA) was used for further analysis. Spearman's correlation was applied for analysing the relationship between illness perceptions, CSI scores and socio-demographic variables. Multivariable analysis was conducted using binary logistic regression. The probabilities for entry and removal of variable in each step were set as 0.05 and 0.1, respectively. 

Results A total of 250 participants with dental caries were included in this study with equal distribution for gender (125 males, 125 females). Median age was 32 years, ranging from 18 to 66 years for the total sample. The socio-demographic characteristics of the participants have been presented in . Almost half of the patients had a caries severity score of 5 (pulpitis) or more for the affected tooth. The frequency distribution of the dental caries symptoms associated with the identity component of IPQ-R have been presented in . The study participants have attributed a high proportion of symptoms to their illness. The total identity score had a mean of 8.71 (2.4) and a median of 9 (3). Descriptive statistics of composite score of dimensions of IPQ-R were also calculated. The participants generally experienced their condition as being acute rather than chronic (timeline acute/chronic mean score = 12.46), with little variation (timeline cyclical mean score = 13.38) and a negative impact on their lives (consequences mean score = 18.77). Moreover, they also felt that their illness was controllable both personally (personal control mean score = 22.58) and through treatment (treatment control mean score = 21.88). It had a negative emotional response to their illness (emotional representation mean score = 20.40) and generally reported moderate understanding their illness (illness coherence mean score = 16.53). As reported in , germ/virus, diet and poor medical care in the past were the most commonly reported agents of causation of dental caries. describes the correlation of socio demographic variables, caries severity with the components of IPQ-R. Caries severity was positively correlated with timeline acute/chronic, timeline cyclical and consequence, which indicates patients with a more severe disease believed that the disease was going to last for long, recur frequently and have serious consequences. Significant correlations were observed in other variables as well. displays the correlation matrix between the 12 items of IPQ-R. The identity component was positively correlated with personal control which describes that when the participants’ awareness of the symptoms increases their belief about personal control. The timeline (acute/chronic) component was positively correlated with timeline cyclical and consequence, indicating those who believed caries to be a chronic condition also believed it to be recurring with serious consequences. It was negatively correlated with treatment control, illness coherence and immune attribution. This indicates patients who consider dental caries as a chronic condition believed that treatment has no control over it had less understanding of the condition and was due to immunological attribution. Similar observations were noted between other IPQ-R components as well. 

Discussion Illness perception is an important predictor of how a personacts and copes during an illness. Patients often build their own representations or models which help them make sense of their experiences and provide a foundation for their coping responses. We have made an attempt to explore the dimensions from the IPQ-R and their relationship to the symptoms of dental caries as reported by the patients. Similar to the findings of a study conducted in Colombia by Mafla A. C. et al. “treatment control” was the highest scored IPQ dimension. Most of the people perceived that this disease can have a serious consequence but they have the capacity to control their illness, which can be well reflected from their treatment seeking visit to the hospital. The participants also had a strong belief about the temporary nature of the condition as reflected by a low mean score for dimensions “timeline acute/chronic” and “timeline cyclical”, contrary to that reported by Mafla A. C. et al. This belief of the participants is in line with the natural history of dental caries as the disease can have serious outcomes and can be prevented as well as treated. It was interesting to note that alcohol, environmental pollution and family problems were mistakenly attributed as etiological factors for dental caries. This reflects the deficiency in cognition of the etiology of dental caries among 1/3rd of the study sample. This dimension of IPQ-R for dental caries has been rarely investigated. With regard to identity component of IPQ, some vague associations related to dental caries were loose teeth and sore throat. There was a disparity between somatization (I experience this symptom when I have dental caries) and belief (I believe that these symptoms might be associated) regarding symptoms associated with dental caries. This resulted in a higher number of participants, who believed in such symptoms, to visit health care facilities without ever experiencing them. This finding is contrary to that obtained by Mafla A. C. et al., where the percentage association was almost similar. This was one of the objectives of modifying IPQ original questionnaire. This anticipation of pain can act as a motivating factor especially for dental caries, where early lesions can be asymptomatic, manifesting in form of a hole in the teeth. Most of the socio-demographic factors were related to the IPQ-R dimensions. Contrary to findings of Mafla A. C. et al., age was correlated with treatment control positively and emotional representation negatively. As age advances because of the development of cognitive and psychomotor skill, emotional representation of any illness decreases and the perception of the mind about the control of disease by treatment increases. Females had a higher score for “timeline cyclical”, “consequence” and “emotional representation” than males but lower scores for “illness coherence”. Education was associated positively with identity, consequence, illness coherence but negatively with timeline cyclical and emotional representation. Similar observations were reported by Mafla A. C. et al. in Columbia. As far as association between caries severity and various dimension of IPQ-R is concerned, significant positive correlation was obtained for timeline acute/chronic, timeline cyclical and consequences. Hence people with a more severe disease believed that the disease is going to last for long, with reoccur frequently and will have a serious consequences. 4.1 Strengths and limitations Illness perceptions and patient expectation beliefs are essential in predicting health outcomes, including self-management behavior and quality of life. The primary strength of the study lies in its novelty in assessing the perception and beliefs about dental caries using IPQ-R and CSI. IPQ-R is a revised extended version of the original scale, which includes an assessment of understanding as well as emotional response to their illness. This tool has better psychometric property and was also cross-culturally validated by the researchers. Another strong suit is the use of Caries Severity Index, which expresses the depth and extent of the lesions. However, the study was not without its limitations. Firstly, due to its cross-sectional design, causality cannot be established. Also, the participants were selected from a hospital setting, hence may not be representative of the population. Moreover, further studies need to be carried out with a larger sample size. 

Strengths and limitations Illness perceptions and patient expectation beliefs are essential in predicting health outcomes, including self-management behavior and quality of life. The primary strength of the study lies in its novelty in assessing the perception and beliefs about dental caries using IPQ-R and CSI. IPQ-R is a revised extended version of the original scale, which includes an assessment of understanding as well as emotional response to their illness. This tool has better psychometric property and was also cross-culturally validated by the researchers. Another strong suit is the use of Caries Severity Index, which expresses the depth and extent of the lesions. However, the study was not without its limitations. Firstly, due to its cross-sectional design, causality cannot be established. Also, the participants were selected from a hospital setting, hence may not be representative of the population. Moreover, further studies need to be carried out with a larger sample size. 

Conclusion The cross-culturally validated version of IPQ-R allowed proper assessment of cognitive and emotional illness perception in dental caries. Illness perception showed wide variability among patients .Most of the participants considered the disease to be of short duration. Though they perceived that the disease could have serious consequence and the symptoms might be emotionally disturbing, they could well control their problem by seeking treatment. The socio-demographic variables like age, gender, education, SES, and severity of the carious lesion influence various dimension of illness perception. Most of the patients perceived cavity, pain, and sensitivity as identifying symptoms of dental caries. The finding of the study can help oral health care professionals to develop various illness perception based interventions for effective prevention and therapeutic management of the most prevalent dental disease. 

Ethical approval has been obtained from Institutional ethical committee of SCB Dental College and Hospital (IEC/SCBDCH/046/2019). 

Nil. 

Nil. 

I have read the Subject Information Sheet and its contents were explained. I had the opportunity to ask questions and received satisfactory answers. I understand that mine as well as my child's participation in the study is voluntary and that I have the right to withdraw at any time without giving any reason and without my medical care or legal rights being affected. I agree to take part in the above study. I confirm that I have received a copy of the Subject Information Sheet along with this signed and dated informed consent form. 

Nil. 

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. 

