However, to reduce bias reporting, the child could fill out a questionnaire. This is a disadvantage since younger children cannot comply with this satisfactorily. It is therefore impossible for researchers to obtain directly, the viewpoints of very young patients30. To circumvent this problem, various techniques have been developed whereby the child can indicate his/her level of anxiety by picking out or pointing to a picture that illustrates the perceived emotion. These picture scales allow for limited cognitive and linguistic skills and can be easily administered and scored in a clinical context. One of such developed picture test is the Facial Image Scale37.
The Facial Image Scale uses faces as an indicator of fear. It is a visual analogue scale comprising of a row of five faces ranging from very happy to very unhappy. Children are asked to point at which face they felt most like at the moment. The face is scored by giving a value of one to the most positive affect face and five to the most negative affect face with faces 4 and 5 indicating high dental fear. The tool was found to show a high correlation with the Venham Picture Test (VPT) when tested for validity37,49. It is constructed to measure situational dental fear but there are no studies yet to establish its reliability in measuring dental fear in children. It is however, quick and easy to administer.
This technique has its limitations. It is reported that younger children misinterpret drawings of facial expressions more often than older children50. The scale may also not be appropriate for older children as studies show a distorted pattern of score distribution in older children therefore not lending itself to good discrimination between them51. In addition, some of the pictures are ambiguous in what they portray and do take time to complete37.
One other limitation of the picture test is its limited use in children who cannot identify themselves with the pictures shown52.
Despite the availability of multiple diagnostic tools for formal assessment of dental fear, less than 20% of dentists use them53 routinely in clinical practice. In everyday practice, most of the diagnosis of dental anxiety is based on clinical judgment. Very few studies have however been done to validate the use of subjective clinical judgments in the diagnosis of dental fear in children. Further studies need to focus on this and then develop objective methods for judging and identifying dental fear quickly and easily in children. This would enable prompt use of appropriate techniques to manage the dentally fearful child.