On the structure of childhood dental fear, using the Dental Subscale of the Children s Fear Survey Schedule

Transcription

1 On the structure of childhood dental fear, using the Dental Subscale of the Children s Fear Survey Schedule M. TEN BERGE* **, J.S.J. VEERKAMP*, J. HOOGSTRATEN** ***, P.J.M. PRINS**** ABSTRACT. Aim The aim of the present study was to assess the structure of childhood dental fear, using the Dutch parent s version of the Dental Subscale of the Children s Fear Survey Schedule (CFSS-DS) and to report on its validity. Materials and methods Factor analysis (principal components, varimax rotation) was performed using the scores of a group of high fearful children (n=322). Results were compared with those from a previous study among low fearful children, also using the parent s version of the CFSS-DS. In addition, mean item scores between the samples were compared to examine specific differences. Results Factor analysis resulted in a stronger factor pattern than that found in previous research. Four factors accounting for 60% of the variance were found: 1) fear of general, less invasive aspects of dental treatment; 2) fear of medical aspects; 3) fear of drilling; 4) fear of strangers. Conclusion It was concluded that with increasing fear levels, underlying factors of dental fear can be distinguished more clearly. The CFSS-DS was indicated to be a reliable and valid measure of dental fear. KEYWORDS: Factor structure, Dental fear, Children, Treatment, Validity Introduction The Dental Subscale of the Children s Fear Survey Schedule (CFSS-DS) was developed to provide an instrument for assessing dental fear in children [Cuthbert and Melamed, 1982]. The CFSS-DS is a revised form of the Fear Survey Schedule for Children (FSS-FC) to include specific dental fear items as one of its subscales [Scherer and Nakamura, 1968; Melamed et al., 1975; Cuthbert and Melamed, 1982]. Since its development, this scale has become a well known tool in the study of dental fear. Previous studies have demonstrated the scale to have good internal consistency and test-retest reliability [Melamed et al., 1978; Klingberg, 1994; Aartman et al., 1998]. In addition, the validity of the scale proved acceptable [Melamed et al., 1978; Klingman et al., 1984; Klingberg, 1994; Milgrom et al., 1994; *Department of Cariology, Endodontology, Pedodontology **Department of Social Dentistry and Dental Health Education, Academic Centre for Dentistry, Amsterdam, The Netherlands ***Department of Psychological Methods ****Department of Clinical Psychology, University of Amsterdam, The Netherlands Klingberg et al., 1995; Aartman et al., 1998]. Normative data have been reported for American, Singaporean, Swedish, Finnish and Chinese populations [Cuthbert and Melamed, 1982; Chellappah et al., 1990; Alvesalo et al., 1993; Klingberg et al., 1994; Milgrom et al., 1994; Milgrom et al., 1995]. Less research, however, has been carried out on the factor structure of the scale, that is, on the structure of childhood dental fear. This seems to be important for understanding its aetiology more clearly and for selecting the appropriate treatment strategy. In the studies reporting on the results of a factor analysis, similar factor patterns were found, despite differences in populations and methods [Alvesalo et al., 1993; Milgrom et al., 1994; Ten Berge et al., 1998]. The results indicated that in general three separate factors can be distinguished: 1) fear of highly invasive procedures; 2) fear of less invasive treatment aspects; 3) fear of medical aspects and strangers. In a previous study in the Netherlands, however, it was concluded that the CFSS-DS essentially seemed to measure a one-dimensional construct, given that after principal components analysis most 73

2 M. TEN BERGE ET AL. items loaded strongly on the first factor [Ten Berge et al., 1998]. In this study children from a general dental practice participated, indicating that the children s average level of fear might have been relatively low. As high dental fear often interferes with effective dental treatment, it is vital to ascertain whether these earlier findings also apply to highly fearful children. Therefore, the present study was undertaken. The aim of this study was to further examine the structure of childhood dental fear and to determine which aspect accounts for the strongest part of dental fear, in a population of highly fearful Dutch children. The factor analysis performed earlier, using scores of a group of low fearful Dutch children [Ten Berge et al., 1998], was replicated using the scores of a group of children referred to a dental fear clinic. In addition, the validity of this Dutch parent s version of the CFSS-DS was assessed. In the present study, the general level of fear was higher than that of the children in the previous study. Subsequently, the question arose whether all mean item scores on the CFSS-DS indeed showed this increase, as supporting evidence of the validity of the questionnaire. Also, possible differences in ranking of the items between the study samples were studied. Materials and methods Subjects. This study was conducted among 322 children (172 girls) between 4 and 12 years of age (mean 6.3, SD 1.8), treated in a dental fear clinic (SBT) in Amsterdam. All children were referred to the clinic because dental treatment by their regular dentist was impossible due to dental fear (all children scored 32 or higher on the CFSS-DS) [Ten Berge et al., 2002a]. Procedure. After initial referral to the clinic, the parents of all children were asked to participate by completing the Dutch parent s version of the CFSS- DS at home and to return the questionnaire at the clinic at their first visit. As the younger children were not able to answer the questionnaire by themselves and in order to enable comparisons between the different age groups, the scale was adjusted to be answered by one of each child s parents. Research has indicated that parents are quite able to assess their child s dental fear [Klingberg et al., 1994; Milgrom et al., 1994]. All parents were well informed on the purpose of the study and they all signed a consent form. The CFSS-DS consists of 15 items, related to various aspects of dental treatment. Each item can be scored on a 5 point scale from 1 (not afraid) to 5 (very afraid). Total scores thus range from 15 to 75. Data analysis. Mean scores on all items and a total fear score were calculated. To test the internal consistency of the Dutch parent s version of the CFSS-DS, reliability analysis (alpha) was performed [Cronbach, 1990]. Statistical t-tests were performed to assess differences in fear level between the present fearful sample and the low fearful sample from a previous study [Ten Berge et al., 1998]. To assess the factor structure of the questionnaire and to determine which factor accounted for the strongest part of dental fear in children, factor analysis (principal components, varimax rotation) was employed. This uses the correlations between items on a scale as the basis to determine whether subsets of items (factors) exist that might relate to each other strongly, even though all scale-items are related to the general concept of interest, in this case dental fear in children. Factor scores above 0.5 indicate a strong loading on a particular subset of items. The strength of these subsets is usually represented in eigen values, indicating which factors, or subsets of items, account for the strongest part of the total scale variance. Eigen values above 1.0 are considered strong enough to be taken into account. Results The mean total CFSS-DS score was (SD 9.58). As expected, all mean item scores of the children in the present study were significantly higher than the mean item scores of the low fearful Dutch group (p<0.05). Table 1 shows the mean item scores and ranking of the highly fearful group (HFC) of the present study and of the low fearful group (LFC) of the earlier Dutch study [Ten Berge et al., 1998]. Although small differences existed between the groups, item-ranking order was generally the same (Spearman s rho=0.721, p=0.002). Highest fear scores were obtained on the items drilling, dentists and injections. For the low fear group injections, drilling and having to go to the hospital were highest in rank. No relation was found between age and fear score or between gender and fear score (p>0.05). The internal consistency of the scale proved to be good; Cronbach s alpha was Factor analysis. Principal components analysis resulted in four factors with eigen values above 1.0: 4.51, 1.85, 1.45 and 1.20 respectively. Again [Ten 74

3 ON THE STRUCTURE OF CHILDHOOD DENTAL FEAR HFC Item mean SD rank mean SD rank 1. dentists * doctors * injections (shots) * having someone * examine your mouth 5. having to open your mouth * having a stranger touch you * having somebody look at you * the dentist drilling * the sight of the dentist drilling * the noise of the dentist drilling * having somebody * put instruments in your mouth 12. choking * having to go to the hospital * people in white uniforms * having the nurse clean your teeth * LFC total CFSS-DS * * = p<0.05 TABLE 1 - Mean CFSS-DS scores for high fearful (HFC; n=322) and low fearful children (LFC; n=150) in a population of Dutch children. Berge et al., 1998], most items loaded relatively high on the first factor, although eight items now loaded below 0.60 (ranging from 0.31 to 0.53). Principal components analysis, after varimax rotation, also resulted in four factors with eigen values above 1.0, accounting for 60% of the variance. The first factor consisted of items related to general aspects of dental treatment such as having to open your mouth and having somebody put instruments in your mouth. The second factor consisted of items related to medical aspects of treatment such as doctors and hospitals. The third factor consisted of the three items related to drilling, and the fourth factor consisted of items related to strangers such as having a stranger touch you (Table 2). Discussion The results of the present study are generally consistent with those among low fearful children. Similar factors were found after factor analysis, although analysis using only the scores of high fearful children resulted in a somewhat stronger, more specific factor pattern. In the previous study [Ten Berge et al., 1998], three separate factors were found, but close inspection of the factor loadings showed that almost all items loaded strongly on the first factor, indicating essentially one primary underlying dimension. In addition, principal components analysis, after varimax rotation, showed that several items loaded substantially on more than one factor. It was therefore concluded that although 75

4 M. TEN BERGE ET AL. Factor I Factor II Factor III Factor IV eigen value total scale variance 18% 16% 14% 12% 1. dentists 0.685* doctors * injections (shots) * having someone 0.847* examine your mouth 5. having to open your mouth 0.787* having a stranger touch you * 7. having somebody look at you * 8. the dentist drilling * the sight of the dentist drilling * the noise of the dentist drilling * having somebody 0.436* put instruments in your mouth 12. choking * 13. having to go to the hospital * people in white uniforms * having the nurse clean your teeth 0.474* *Strong factors loadings TABLE 2 - Rotated factor matrix (principal components, varimax rotation) for a group of highly fearful Dutch children (n=322). separate factors were found, the CFSS-DS essentially measures a one-dimensional concept of dental fear [Ten Berge et al., 1998]. In the present study, however, factors could be distinguished more clearly, with most items loading strongly on only one factor. This factor analysis resulted in four factors which can be defined as follows: 1) fear of general, less invasive aspects of dental treatment; 2) fear of medical aspects; 3) fear of drilling; 4) fear of strangers. This small, though interesting, difference in factor pattern seems to indicate that fearful children may be better able to distinguish between different aspects of dental treatment than low fearful children, probably as a logical result of their high dental fear and associated higher anticipation level. Thus, these results provide support for an underlying factor structure of the CFSS-DS; it seems that separate concepts do exist within the general concept of dental fear, becoming more distinguishable in highly fearful populations. Although it was indicated that for a part of the fearful children their fear is associated with drilling (factor III), the results also show that for some children their fear is related to strangers (factor IV) or medical situations in general (factor II). Being able to distinguish and to identify these factors in fearful 76

5 ON THE STRUCTURE OF CHILDHOOD DENTAL FEAR children is of importance to the dentist in daily practice. That is, the scale provides specific information on the most fear-evoking aspects of dental treatment for children individually, which is important for selecting the most effective management strategy. For example, it seems plausible that for children especially fearful of drilling a different treatment approach may be more effective than for children fearful of strangers. A child highly fearful of drilling may specifically benefit from a management approach introducing this aspect on a stepwise basis by gradual exposure [Ten Berge, 2001], thus enabling the child to become familiar with the drill and associated aspects, such as sounds or feeling, in a gradual manner. In view of this clinical utility of the CFSS-DS it is, however, important to note that its value lies especially in this screening of specific aspects of dental fear and subsequent incorporation in treatment, while its predictive value with respect to behavioural problems is relatively low. That is, the CFSS-DS does seem to indicate the level and nature of a child s dental fear adequately, but should not be used to predict the child s behaviour during treatment in terms of cooperation or potential behavioural management problems [Ten Berge et al., 2002b]. Other situational and temperamental aspects, of course, play an additional and important role in the actual behaviour displayed by a child during a dental visit, such as individual coping style or temperament, the nature of dental treatment or possibly also the dentist s behaviour or attitude. With respect to the most fear-eliciting items of the CFSS-DS, the results of the present study are also generally in agreement with those of previous studies. Drilling and injections were ranked high for the high fearful as well as for the low fearful groups of children, although in some of the other studies being touched by a stranger and choking were ranked higher [Chellappah et al., 1990; Alvesalo et al., 1993; Milgrom et al., 1995; Raadal et al., 1995]. Interestingly, in the present study the item dentists is among the three highest ranked items for the high fearful children, while for the low fearful children this was the item having to go to the hospital. No relation between dental fear and gender or age was found, most likely due to the overall relatively high fear level in this study population. Conclusion The results of the present study have indicated that the Dutch parent s version of the CFSS-DS generally operates in the same way in different populations, but that it does discriminate better in a population with a higher level of dental fear. In comparison with the previous study among low fearful children [Ten Berge et al., 1998], a stronger factor pattern was found indicating that separate factors do exist within the general concept of dental fear, accounting for a stronger or lesser part of this fear. In addition, all items of the CFSS-DS were found to reflect the mean fear level of the study populations, providing additional support for its validity. Therefore, it can be concluded that the internal structure of the Dutch parent s version of the CFSS-DS is reliable and stable, and that the scale is a valid instrument for assessing dental fear in children. 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