The Development and Evaluation of the Slovenian Version of the Early Childhood Oral Health Impact Scale (ECOHIS-SVN)

Oral health affects an individual’s overall health and quality of life (1). For many years, deviations in oral health were described only by oral clinical signs and symptoms, without assessing the actual impact of oral diseases on the quality of patients’ daily lives (2). Oral Health-Related Quality of Life (OHRQoL) is influenced by various factors, including the presence of oral pain (3), malocclusions and dental diseases (4), as well as many other factors (e.g. socio-economic status) (5).

In adults, several instruments have been in use to measure the impact of oral health on quality of life (6). One of the most frequently used is the Oral Health Impact Profile (OHIP) (7) and its short version (OHIP-14) (8). The original OHIP-14 has also been translated into Slovenian and validated for use in the Slovenian population (9).

In children, especially in the preschool population, only a few instruments are available to assess OHRQoL. In 2007, the Early Childhood Oral Health Impact Scale (ECOHIS) questionnaire was introduced to assess the impact of OHRQoL on pre-schoolers and their families (10). Since then, ECOHIS has been translated and validated in several languages (11-18). To date, no valid and reliable instrument for assessing OHRQoL in preschool children has been available in the Slovenian language. The development of the Slovenian version of the ECOHIS questionnaire will enable further research studies that will measure and compare the impact of oral health-related quality of life of Slovenian preschool children in relation to various diseases and/or treatments, as well as comparison of the results of such studies with similar studies conducted around the world.

This study aimed to translate and validate the Slovenian version of the ECOHIS questionnaire (i.e. the ECOHIS-SNV). Due to the children’s immaturity, including their cognitive and linguistic limitations, which prevent them from disclosing past events and self-reporting OHRQoL, children’s OHRQoL assessments are usually based on their parents’ reports. Since studies have found that their subjective perceptions are also influenced by socioeconomic characteristics (5), the researchers sought a possible correlation between the ECOHIS-SNV results and parents’ age, level of education, self-reported oral health status and OHIP-SVN14 score.

The original English ECOHIS questionnaire was translated into Slovenian using the forward-backwards translation method by two native Slovenian speakers. Both translations were compared and merged into a single ECOHIS-SVN version (Figure 1). The Slovenian version was back-translated into English by two independent native English speakers. Both versions were compared and synthesised, and the English translation of the ECOHIS-SVN was compared with the original English version.

Figure 1.

The ECOHIS questionnaire, inquiring about the frequency of particular events in the child’s life thus far, is divided into two main parts: the section on the impact on the child (9 items) and the section on the impact on the family (4 items). The child impact section contains four subscales: symptom (1 item), child-related function (4 items), psychology (2 items) and self-image/social interaction (2 items). The family impact section comprises two subscales: parental distress (2 items) and family-related function (2 items) (10). The total score of the completed ECOHIS questionnaire is the sum of the responses to all 13 questions. For each question, the selected response is scored as follows: 1=never, 2=hardly ever, 3=occasionally, 4=often, 5=very often. The ECOHIS summary score ranges from 13 to 65; the scores for the child and family sections may range from 9 to 45 and 4 to 20, respectively. A higher total score means a lower quality of life. An alternative response, “I do not know”, was also available. Parents responding to one or more questions with “I do not know” were excluded from the analysis.

To participate in the study, the researchers invited all children under six years of age from two kindergartens in Ljubljana and their parents. The researchers thoroughly explained to the parents the aim and the course of the study and its voluntary nature. The study included only children with no systemic disease, motor or cognitive impairment, children who were willing to take part in the dental examination, and whose parents had given written informed consent for participation. The study was conducted in accordance with the Helsinki Declaration and approved by the Slovenian National Committee for Medical Ethics (Act No. 0120-484/2019/14).

All children underwent a clinical dental examination by a trained and calibrated examiner. In each child, dental caries and caries-affected teeth were recorded according to the WHO criteria for visual assessment of dental caries (19). The entire group of children was divided into two subgroups: children with dentine caries lesions (dmft>0) and children without dentine caries lesions (dmft=0). A modified plaque assessment scoring system (PASS) was used to assess plaque accumulation (20). As suggested by the authors, the presence or absence of dental plaque was recorded on 20 surfaces; instead of the first permanent molars, the researchers checked for the presence of plaque on the second deciduous molars and one upper central incisor. If the second deciduous molar was absent, the presence of plaque was assessed on the first deciduous molar. In the presence of dental plaque at one or more sites, the subject was categorised into the group with dental plaque (DP>0), while a child without detected dental plaque was classified into the group without dental plaque (DP=0).

During the visit, parents were asked to complete ECOHIS-SVN. Three weeks later, parents of the first 30% of children in whom dental examinations were performed were invited to re-complete the ECOHIS-SVN questionnaire. The ECOHIS-SVN internal consistency was tested using Cronbach’s alpha coefficient (21). Test-retest reliability was assessed by the intra-class correlation coefficient (ICC) according to Shrout and Fleiss (22); more specifically the ICC (3,1). This calculation, based on a two-way mixed-effect model, as the two consecutive measurements (test-retest setting) were not randomized samples and it is built on the assumption of absolute agreement between measurements of the two consecutive time points.

The convergent validity of the ECOHIS-SVN was assessed according to Pahel and co-authors (10). The researchers compared the results of each of the ECOHIS-SVN sections (the child and the family) with the responses to either of two questions relating to the child’s overall and dental health (“In general, how would you rate the overall health of your child?” and “In general, how would you rate the dental health of your child?”). For each of the two questions, parents selected one of the following responses: 1=excellent, 2=very good, 3=good, 4=fair, and 5=poor (10). Convergent validity was assessed with Spearman’s rank correlation.

Criterion validity was tested between groups of children who differed in two oral health indicators: tooth affection due to dentine caries lesions (dmft=0 and dmft>0) and dental plaque presence (DP=0 and DP>0). Differences in the scale score distributions between the groups of children on the two indicators were tested with the Mann-Whitney test. The magnitude of the statistical difference was assessed by calculating the effect size (23).

In the second part of the study, the researchers examined the relationships between some characteristics of the parents (age, educational level, self-reported oral health and OHIP-SVN 14) on the responses they gave in the ECOHIS-SNV questionnaire. For this purpose, parents indicated their age and level of education (primary, secondary school or university). Education was included in the form of dummy variables. They also answered with “yes” (scored as 1) or “no” (scored as 0) to each of four questions: “Do you have tooth fillings?”, “Do you have a tooth or multiple teeth replaced with a prosthetic substitute (i.e. crown, bridge, denture)?”, “Do you have periodontal disease?”, and “Have you had any teeth extracted due to caries or periodontal disease?”. In addition, each parent also completed the OHIP-SVN14 questionnaire, which asks about the parent’s oral health-related quality of life (9). For each of the OHIP-SVN14 questions, one of the following responses could be selected: 0=never, 1=hardly ever, 2 =occasionally, 3=often, 4=very often. Multiple linear regression analysis was used to assess the association between ECOHIS-SVN results and the parents’ age, level of education, self-reported oral health status and the parents’ OHIP-SVN14 score. Due to the heteroscedasticity and non-normal distribution of residuals, the bootstrapping method was used to obtain reliable confidence intervals for regression coefficients. The same analysis was also conducted on the dmft=0 subgroup. Statistical analysis was performed using SPSS for Windows, version 25.0 (IBM Corporation, Armonk, NY, USA) and R Statistical Software (version 4.1.3). A p-value ≤0.05 was considered statistically significant.

The original ECOHIS questionnaire was translated without major adaptations. Minor adaptation in the ECOHIS-SVN was required, as the term “kindergarten” replaced both terms used in the original ECOHIS questionnaire (i.e. “preschool” and “daycare”).

Of 462 invited children, 255 children, 130 boys (51%) and 125 girls (49%), with a mean age of 4.8 years±0.8 (boys 4.9±0.8 and girls 4.8±0.8) participated in the study (Figure 2).

Figure 2.

In the entire study group, 115 children had at least one tooth affected with dentine caries (45.1%). In the entire group of children, the mean dmft was 2.34±3.61, and in the dmft>0 subgroup, the mean dmft was 5.19±3.75. The total number of teeth affected with dentine caries lesions (n=597) and proportions of decayed, missing and filled teeth were 82.8%, 1.5%, and 15.7%, respectively.

For each child, the ECOHIS-SVN questionnaire was fully completed by her/his parent; 205 mothers (80.4%) and 50 fathers (19.6%). For the entire group, the mean ECOHIS-SVN total score was 15.3 (15.1 for boys and 15.6 for girls). The distribution of responses to ECOHIS-SVN is presented in Table 1. In the child impact section, oral/dental pain was the most frequently reported problem (10.2% answered “occasionally”, “often”, and “very often”), while in the family impact section, feelings of guilt (10.2%) was ranked highest. However, it should be emphasised that 50.3% of parents reported not noticing the problems described in the ECOHIS-SVN questionnaire, indicating a strong floor effect, while the ceiling effect was negligible (Table 2).

The ECOHIS-SVN score reliability in the study sample is shown in Table 3. Cronbach’s alpha was 0.85 (the lower limit of the 95% CI is 0.82) and therefore considered to be satisfactory for a reliable comparison between groups (24). Parents of 71 children (28%) re-completed the ECOHIS-SVN questionnaire three weeks later. In this subgroup, the mean ECOHIS-SVN scores of the baseline and of the additional completion of the questionnaire were 14.79±3.28 and 14.41±2.89, respectively. The ICC was 0.85 (95% CI ranging from 0.76 to 0.91).

As for the ECOHIS-SVN validity, a statistically significant correlation was confirmed between ECOHIS-SVN and general health, as well as the dental health-rating question (Table 4). The Spearman correlation coefficients for the total ECOHIS-SVN scores and the general or dental health question were 0.60 and 0.75, respectively. This moderate-to-high correlation confirms the convergent validity of the ECOHIS-SVN. Testing criterion validity, a statistically significant difference was found between the groups of children affected with dentine caries and children without dental caries lesions (p<0.001). Regarding the plaque accumulation status of the children, score differences were statistically significant in the child impact section and the total ECOHIS-SVN. The effect size of the total ECOHIS-SVN scores between children with and without caries was 0.76 (child impact section=0.74, family impact section=0.52), and regarding the plaque accumulation status, 0.40 (child impact section=0.49, family impact section=0.21).

In the framework of the second part of the study, the researchers found that the majority of parents belonged to the age group between 20 and 40 years of age (67.5%), had a university degree or some level of higher education (61.2%), and the most common number of points on self-reported oral health was one (53.3%). The mean OHIP-SVN14 score of the parents of the entire group of children was low (4.61±5.09).

Multiple linear regression models confirmed a statistically significant association only between ECOHIS-SVN and parents’ age (Table 5). The education, self-reported oral health and OHIP-SVN14 were non-significant in all three ECOHIS-SVN sections. In the subgroup of children with dmft=0, higher OHIP-SVN14 values of parents were statistically significantly accompanied by higher values of ECOHIS-SVN of children (Table 6).

The main goal of this study was to develop the Slovenian version of the ECOHIS questionnaire: the ECOHIS-SNV. The development of the questionnaire in the local language enables further research studies that will measure and compare the impact of the quality of life of Slovenian preschool children in the case of various diseases of the oral cavity and/or treatments (e.g. comparisons of different treatments methods, choices of different materials). Furthermore, it also enables comparisons of the results of such studies in the preschool population in Slovenia with similar studies conducted around the world. To achieve this goal, the researchers assessed its internal consistency, test-retest reliability, and its convergent and criterion validity. In this way the researchers obtained the first questionnaire in the Slovenian language that enables the appraisal of the quality of life of preschool children concerning their oral health.

The selection of the sample size and corresponding power was based on previous ECOHIS validation studies, which were conducted on groups ranging between 111 and 492 participants (10-18, 25) and are consistent with recommendations for assessing construct validity, ceiling/ floor effects, internal consistency and factorial analysis (26). The results of ECOHIS-SVN validation are in accordance with previously published studies evaluating this OHRQoL measure. Cronbach’s alpha was 0.85, which is comparable to results between 0.82 and 0.95, as found in the previous studies (10-14, 16, 18). Another measure of the scores’ internal consistency (mean inter-item correlation) ranged between 0.15 and 0.50, as recommended (27). ICC of 0.85 was also comparable to the previously reported ICC values between 0.81 and 0.86 (10, 11, 15, 17, 18) and indicates good test and retest agreement (28). The researchers have confirmed a strong correlation between the ECOHIS-SVN scores and the general and dental health rating questions, whereas it was weak to moderate in the previous studies (10, 14, 18). The ECOHIS-SVN scores discriminated between children with and without cavitated caries, as well as between children with or without accumulated dental plaque (p<0.001), as in previous studies (10, 15, 18).

The mean ECOHIS-SVN total score of the whole group was 15.34. Parents most repeatedly answered questions related to “pain” (10.2%), “guilt” (10.2%), and “upset” (9.9%) with “very often”, “often”, or “occasionally”. Furthermore, they reported their child’s difficulty in “pronouncing words” (4.4%) and “eating” (3.6%). While “pain” and “difficulty eating” are often reported in studies (10, 14, 18), difficulty in pronouncing words was highlighted only in this study.

The limitation of this study was that no pilot study with at least a dozen subjects included had been previously conducted (29). A further limitation was a strong floor effect observed, with 70–98% of parents (depending upon the item) reporting that their children “never” experienced oral health problems. Other validation studies reported similar findings (10, 12, 14, 15). This may have been due to the low level of oral health problems experienced by the participating children and/or the fact that parents did not pay attention to their children’s oral diseases until pain was present. Indeed, in this study, only 15.7% of teeth affected with cavitated dentine caries lesions were filled.

With this study, a reliable and valid instrument has been developed for assessing the OHRQoL of preschool children in the Slovenian-speaking population. Although ECOHIS is primarily intended for use in epidemiological research and with limited use in clinical practice, it is used by health professionals to assess preschool children who can have a variety of dental, orthodontic and craniofacial conditions (30). The ECOHIS-SVN enables further studies to assess the effects of oral diseases and their treatment modalities on the OHRQoL of preschool children.