Reliability and validity of the Serbian version of Children ' s Dental Fear Questionnaire

Background/Aim. Dental anxiety leads to avoidance of dental treatment and could lead to impaired oral health. The aim of this study was to determine the reliability of the Serbian version of Children’s Fear Survey Schedule Dental Subscale (CFSS-DS) and the relations between dental anxiety and oral health status in a sample of Serbian schoolchildren. Methods. The CFSS-DS scale was translated into Serbian and administered to 231 (12-year old) patients of the Pediatric Dental Department, Public Health Center Čukarica, Belgrade. The number of healthy, decayed, missing and filled teeth (DMFT score) in children was determined by a clinical exam. Results. The average CFSS-DS score was 26.47 ± 10.33. The girls reported higher anxiety than the boys (p < 0.05). Most common fears were drilling, choking, going to the hospital and anesthesia. Lower CFSS-DS scores were recorded in children with all healthy teeth (p < 0.05). Children with higher CFSS-DS scores mostly visit the dentist due to pain or parental insistence, and those with lower anxiety scores more often visited dentist due to regular check-ups or non-invasive treatments (p < 0.01). A high value of the Cronbach's coefficient of internal consistency (α = 0.88) was found in the entire scale. Conclusion. The Serbian version of CFSS-DS questionnaire is reliable and valid psychometric instrument for evaluation of dental fear in Serbian children. Dental anxiety negatively affects dental attendance and oral health of the examined schoolchildren.


Introduction
Dental fear is a phenomenon frequently encountered in dental practice.Anxiety may lead to avoidance of dental treatment or disruptive behavior during treatment 1,2 , which is stressful both for the patient and the dental team and negatively affects treatment outcomes 3 .People with high dental fear are more likely to delay treatment, leading to more extensive dental problems and symptomatic visiting patterns which feeds back into the maintenance or exacerbation of existing dental fear 4 .
Dental fear (DF) and dental anxiety (DA) in children are proven to be of a multifactor etiology.The experience of pain and trauma during dental treatment has been suggested Correspondence to: Maja Lalić, Department of Preventive and Pediatric Dentistry, Faculty of Stomatology Pančevo, Žarka Zrenjanina 179, 26 000 Pančevo, Serbia.Phone/fax: +381 13 2351 292.E-mail: drmajalalic@gmail.com to play an important role in the onset of dental fear 5,6 .Other factors such as the child psychological development, age, gender and social background are also important 7,8 .No straight cause-consequence model in explanation of children's dental anxiety has been found, because its multifactorial etiology accounts for interaction of different dispositional and situational concomitant factors 9 .
In order to assess a child's anxiety from a more complex view prospective, various measurements are used, since different questionnaires might measure the different aspects of dental anxiety.One psychometric scale that is widely used in pediatric dentistry research is the Children's Fear Survey Schedule Dental Subscale (CFSS-DS), initially presented by Cuthbert and Melamed 10 .The CFSS-DS is a self-report or parental report 15item questionnaire intended to measure DF in children.Satisfactory reliability and validity of the scale has been reported 11,12 .CFSS-DS is commonly used in studies examining prevalence and possible predictors and concomitants of DF in children, and also of correlations between DF and dental behavior management problems 13 .
There is a lack of data on dental anxiety problems in Serbian children.Since the Serbian version of CFSS-DS has not been applied before, our aim was to asses dental anxiety in a sample of children using CFSS-DS, to explore its psychometric properties (the reliability and validity) and to assess the relationship between DF, oral health related behavior and dental status of children.

Subjects
The convenience sample consisted of 231 12-year old children (110 boys and 121 girls), who attended the Pediatric Dental Department, Public Health Center Čukarica, Belgrade.All the patients of this age, regardless their dental status, number of visits or types of treatment previously received, were invited to participate.Patients with symptoms of acute toothache or any other dental emergency (bleeding, swelling, dental trauma) were excluded from the sample.Children with systemic diseases or/and handicap was also excluded.
The parents of the children who participated signed an inform consent form.This research was in accordance with the Declaration of Helsinki and approved by the Ethical Committee of the Faculty of Stomatology in Pančevo, University Business Academy, Novi Sad, Serbia.

Instruments
We used two questionnaires in our study.The first one consisted of 14 questions which pertained to the sociodemographic characteristics of child (gender, family structure and child's grades in the previous academic year), oral hygiene habits (frequency and duration of brushing, use of fluoride supplements), sugar consumption pattern and dental visits behavior (frequency and reasons of dental visits, avoiding treatment, selfperceived treatment needs).
To assess dental anxiety and fear in children, we used the CFSS-DS.English version was translated into Serbian language (Addendum) and back translated by the two bilingual dentists (translation is available from the first author).We used selfreport version of a scale (children were filling the data, which is opposite to parental-report questionnaire, where parents answer to the same questions in behalf of their children).CFSS-DS consists of 15 items related to various aspects of dental treatment.Each item can be scored on a five-grade scale, from 1 (not afraid) to 5 (very afraid).The responses sums ranged from 15 to 75.The scores of 38 and over are used to be indicative of DF in children 14 , and scores of 32 and above of a risk range 15 .Accordingly, we classified the subjects into three groups (Table 1): children with low anxiety levels (with CFSS-DS score < 32), moderately anxious children (≥ 32 score ≤ 38), and anxious children (score > 38).
The children filled-in the questionnaires while sitting in the waiting room prior to receiving the treatment.3) χ 2 = 3.03; df = 2; p = 0.220.

Clinical data
A single trained dentist recorded dental status of children (number of healthy, decayed, missing and filled teeth -DMFT score) under clinical conditions, using a dental mirror and probe, according to the World Health Organization (WHO) criteria.

Statistical analysis
We used the SPSS statistical software (SPSS for Windows, release 17.0, SPSS, Chicago, IL) for analysis.The data were analyzed regarding the questionnaire variables according to the age and gender and tested with the χ 2 test, Student's t-test and one-way ANOVA.Pearson's correlation coefficients were calculated among variables in the total group.The predetermined significance levels were set at 0.05.Cronbach's alpha was used to analyze internal consistency reliability.The exploratory factor analysis was carried out and rotated (Varimax rotation with Kaiser's normalization) to establish the statistical separation of the CFSS-DS items into factors.The decision on the final number of factors was based on the Kaiser's criterion (eigen value > 1).

Table 2 Mean values and standard deviations of Childrens Fear Survey Schedule-Dental Subscale (CFSS-DS) items
Almost two thirds of the children (73.48%) were satisfied with their oral health at the moment of testing.Mean anxiety scores were higher in children who rated their oral health as "poor" or "very poor" than "good" or "excellent" (df = 3; F = 5.013; p = 0.002).
The majority of the children (79.48%) reported dental visit within last year.The children who reported dental visits within past 12 months had a lower mean anxiety score (25.36 ± 8.80) than those who did not visit the dentist for this period (29.08 ± 11.62) or could not remember (31.24 ± 15.43; df = 3; F = 3.435; p = 0.018).Most often, the children visited the dentist due to regular check-up (43.23%); 28.38% stated dental pain as main reason; 9.17% reported visits due to parental insistence and 19.21% of the subjects stated "other reasons" of visits.Higher CFSS-DS scores were obtained in the group of children who mostly visited a dentist due to pain (29.11 ± 11.06) or parental insistence (29.76 ± 13.43), compared with the children who went for regular check-ups (23.86 ± 7.50) or other non pain-related treatments (26.16 ± 10.43; df = 3; F = 4.697; p = 0.003).
Table 2 shows the arithmetic means and standard deviations of the results of CFSS-DS components in the sample.The following CFSS-DS items had the highest mean values in our sample: 8) the dentist drilling, 12) choking, 13) having to go to the hospital and 3) anesthesia (injections), while the lowest mean value was recorded for item 4) having someone examines your mouth.The girls expressed significantly higher dental anxiety than the boys in relation to anesthesia (p < 0.01), strangers (p < 0.001), sound of a drill (p < 0.05) and choking (p < 0.05).

Reliability measures
Cronbach's alpha coefficient of internal consistency in the entire CFSS-DS scale was 0.88.The corrected values of item-total correlations are shown in Table 3  ues were found for item 4 ("someone examines your mouth") and item 7 ("someone is looking at you").In factor analysis (principal component analysis and Varimax rotation with Kaiser normalization) the 3 groups of factors were extracted with eigen values above 1, which explained 59.11% of variance.The results of analysis are shown in Table 4.The first factor explain 22.91% of variance and a high correlation with CFSS-DS item related to the use of dental drill.The second factor explain 21.23% of variance and correlation with fear of doctors, opening the mouth, being watched by strangers, people in white uniforms.The third factor explain 14.97% of variance.It was related to the CFSS-DS items pertaining to the choking, being touched by the strangers and going to the hospital.

Discussion
Although the topic clearly deserves close attention as the crucial dental public health issue 13 , little is known about dental fear among children in Serbia.As cultural and social norms of behavior can affect the development and expression of children's fear, and as dental care systems can vary considerably across cultures, normative data in each culture are needed.The Serbian version of CFSS-DS had high Cronbach's coefficient of internal consistency (α = 0.88), which was in accordance with the findings of the authors from Croatia (α = 0.83) 12 , Bosnia (α = 0.86) 16 , Greece (α = 0.85) 17 , Japan (α = 0.91) 18 and Taiwan (α = 0.94) 13 .
Factor analysis on CFSS-DS in studies of DF in children has been reported in the literature 19 .In samples not selected for high DF, three factors of DF have been indicated: fear of highly invasive dental procedures, fear of less invasive aspects of treatment, and fear of medical aspects and strangers 18,20,21 .In a study of highly DF children, a stronger four-factor pattern explaining 60% of the variance was found: fear of general, less invasive aspects of dental treatment, fear of medical aspects, fear of drilling, and fear of strangers (including choking) 22 .
The factor structure of Serbian version of CFSS-DS scale revealed 3 groups of factors that explained 59.11% of variance.Not a single factor precedes in explaining the total variance of results, which is similar to the study from Japan 18 .The first factor was related to the usual dental situations (the sight and sound of a drill, and drilling) and explained 22.91% of variance.The factor II explained 21.23% of variance in our study and it correlated with the fear of doctors.This factor was also related to the non-invasive dental procedures and being looked at.The third factor explained 14.97% of variance and it was related to choking, strangers and going to the hospital.The similar three factors have been reported in other populations (the Netherlands 20 , Finland 21 ).The factor four was reported in the study on Chinese immigrants in Canada, and the additional factor was related to the fear of being looked at or touched 23 .In a Bosnian version of CFSS-DS the fourth factor was also related to unusual situations that did not belong to usual experiences in dental office or hospital surrounding 16 .
In our study the girls had significantly higher anxiety scores than boys, which is similar to the findings of Majstorovic et al. 24 and Nakai et al. 18 .Children with irregular dental attendance pattern or those who needed dental treatment due to decay also expressed higher DF.In a study of Milsom et al. 25  used with children under 13 years of age 7 .However, all the subjects were able to answer the questions, indicating that the questions were understandable and clear.The limitation of this study is the use of the suitable sample.Therefore, this study should be considered a prospective one, and the results regarding prevalence of high dental fear and DMFT score values could not be generalized to the entire population of Serbian twelve years old schoolchildren.On the other hand, the reliability and validity of Serbian version of CFSS-DS questionnaire could be considered satisfying.The cause and effect dynamics of relationships found between dental anxiety, dental status and visiting patterns need to be further investigated.

Conclusion
Dental health professionals need to understand the dynamic nature of child dental anxiety in order to appreciate hidden feelings and underlying complexity associated with anxious child patients.Anxious children tend to avoid regular dental check-up, more frequently visit dentist due to pain or parental insistence and have more impaired teeth.
The Children Fear Survey Schedule Dental Subscale questionnaire is a reliable and valid psychometric instrument for dental fear evaluation in Serbian children, due to its further application for research of dental fear and numerous associated factors.

R E F E R E N C E S
DF was closely associated with asymptomatic, irregular attendance pattern, a history of extraction and having a dentally anxious parent.We used a self-report version of CFSS-DS questionnaire in children aged 12, although the parental reports are more often Lalić M, et al.Vojnosanit Pregl 2015; 72(7): 602-607.Lalić M, et al.Vojnosanit Pregl 2015; 72(7): 602-607.

value of independent samples (t-test was used to compare means between boys and girls).
*p

Table 3 Corrected values of item-total correlations
. The lowest val-