Are parents of high caries risk Dutch children motivated to brush their children’s teeth? An assessment using the health action process approach questionnaire

The study was approved by the medical ethical committee of the VU University as non-Medical Research Involving Human Subject Act, protocol number 2018-021 and written according to the STROBE guidelines for cohort studies.

In this prospective cohort study, parents/caregivers (from now on referred to as ‘parents’) of children who were referred to a paediatric dental referral practice in Almere, the Netherlands, for treatment of caries, were invited to participate in this study between May 2018 and April 2020. Dental rehabilitations were carried out under intravenous sedation (IVS) or in multiple chairside treatment sessions with behaviour guidance techniques (BGT) by three paediatric dentists and one paediatric dentist in training. These dentists performed both treatments. Parents were included in the study when their child was healthy, ASA I (American Society of Anesthesiologists 2020), aged 3–10 years, and presented with at least three decayed teeth in the mouth spread among at least three quadrants. The parents should have sufficient understanding of the Dutch language to fill out a HAPA-based questionnaire (online supplementary information S1) and sign the informed consent. Parents were excluded when their child had enamel anomalies other than caries or syndromic anomalies of the teeth. Parents were allowed to participate for one child only. In this referral practice, the allocation ratio for IVS versus BGT was 3:1. The sample size was calculated with G*Power3 (Faul et al. 2007). With a two-tailed independent samples t-test with unbalanced groups (3:1), a 0.4 difference in HAPA mean scores (SD = 0.7) between groups (effect size = 0.57), a significance level of 0.05, a power of 0.80, and an oversampling of 20%, a sample of 159 patients was needed.

At intake, parents were informed verbally and in writing by a research assistant about the study procedure. Parents were invited to participate and were assured that they could withdraw from the study at any time without any consequences for the treatment of their child. If parents agreed to participate and signed their informed consent, they were invited to fill out the questionnaire (T1). The paediatric dentist recorded the identification number, date of intake, confirmation of the inclusion criteria, the number decayed (d/D), missing due to caries (m/M), or filled (f/F) teeth in the primary (lowercase) and the permanent (uppercase) dentition together as ‘dmft + DMFT’, and the type of treatment (IVS or BGT) on a registration form. A tooth was considered ‘decayed’ when caries had progressed into the dentine. The paediatric dentist indicated, in agreement with the parents, the type of treatment for the children based on the treatment extension together with the anticipated bearing strength and coping capabilities of the child for the proposed treatment. Hereby, there was no random allocation of the children to one of the types of treatment. The children were treated under intravenous sedation (IVS) or in multiple chairside treatments with behaviour guidance techniques (BGT). The intravenous sedation was performed with propofol and a laryngeal mask. The behavioural guidance techniques that were used include latent inhibition, positive reinforcements, modelling, tell-show-feel-do with shaping and successive approximation and distraction. Children receiving BGT are prepared for treatment during one or more habituation sessions, in which they receive information about the treatment procedure and the dental instruments. The treatments with BGT are split into several sessions to make the treatment acceptable in duration and intensity. Treatments in both groups consisted of restorations (bonded restorations or preformed crowns), pulpotomies, extractions and fluoride applications. Both treatment groups received oral hygiene instructions after dental rehabilitation (T3) as a part of the usual care. Figure 2 presents the timeline of dental rehabilitation per type of treatment. IVS indication was recorded as: young age, extensive treatment plan, limited coping skills, another reason, or a combination of those. Parents were invited to fill out the same questionnaire immediately after dental rehabilitation (T2, i.e., during the last treatment session for BGT and during the check-up after intravenous sedation for IVS) and three months after dental rehabilitation, during their child’s check-up appointment (T3). The follow-up period between T1 and T2 varied depending on the type of treatment and urgency of treatment. The research assistant kept track of the follow-up appointments and prepared the questionnaire for the desk officer to distribute to the parents at the appointments.

The questionnaire was a modification of the HAPA-based questionnaire of Gholami and Schwarzer (2014) adjusted from ‘using dental floss’ to ‘brushing the teeth of your children’. It was translated and validated in previous studies (van Nes et al. submitted). The questionnaire consisted of sociodemographic items (only asked for at T1), four items about the parental brushing behaviour of the child and 32 HAPA-based items to assess the eight HAPA constructs. The 32 HAPA items could be answered on a Likert scale ranging from absolutely not true (1), not true (2), true (3) to absolutely true (4) for the HAPA items of the constructs intention, action self-efficacy, coping self-efficacy, action planning, coping planning and action control. For the constructs outcome expectancies and risk perceptions the Likert scale ranged from most unlikely (1), unlikely (2), likely (3) to most likely (4). Firstly, a mean score of the respective items was calculated for each construct per respondent. As one construct is composed of several items, the mean was calculated by summing the scores on the items of the construct and dividing them by the number of items of that construct, allowing a maximum of one missing value per construct per respondent. For example, for action planning the mean score was calculated by adding the scores of its five items (questions numbered 31, 32, 33, 34, 35) and dividing this score by 5. Then, we calculated the mean score of each construct per type of treatment group. A mean score could range from 1 to 4. When two or more items were missing the respective construct was not included in the statistical analysis.

Sociodemographic items were gender and age of the child and of the mother, country of birth of the child and of both parents, relationship to the child, highest completed education of the mother, and marital status. The level of highest completed education of the mother was dichotomised into ‘low level of education’, including no education, elementary school, lower-level secondary school or other lower levels of education and ‘high level of education’ including higher level secondary school, higher level further education or university. Also, the marital status was dichotomised into ‘single’, including single, divorced or widowed, and ‘with partner’, including married and living together with a partner. The country of birth of the child and of both parents was transformed into the ethnical background of the child.

Several additional items were included. Items regarding parental brushing behaviour of the child consisted of the following questions: who brushes the child’s teeth (‘child only’ or ‘parent/adult together with child’), the actual frequency of brushing their child’s teeth (‘once or less a day’ or ‘twice or more a day’), the believed ideal frequency of brushing their child’s teeth and the frequency of forgetting to brush their child’s teeth (never, once to three times a week, four to seven times a week or more than seven times a week). Also, one item was included about the frequency of brushing the parent’s own teeth and the frequency of the parent visiting the oral health practitioner themselves (‘once or less a year’ or ‘twice or more a year’).

The data were analysed using IBM SPSS Statistics for Macintosh, version 28 (IBM Corp., Armonk, N.Y. USA). Independent samples t-tests were used to compare the mean HAPA scores, child brushing frequency per day, mean dmft + DMFT, and mean age of the child and the mother at baseline between the IVS and BGT groups. Furthermore, we compared these variables between parents that completed all three questionnaires (T1, T2 and T3) and the parents that completed only the first questionnaire (T1) to reveal potential differences between these parents. Likewise, differences in categorical baseline variables between the IVS and BGT group and between parents that completed all three questionnaires (T1, T2 and T3) and the parents that completed the first questionnaire only (T1) were assessed using the chi-square test. For baseline comparisons significance levels were set at 5%.

The changes in mean HAPA scores during the treatment period were assessed with repeated measures ANOVA with post hoc LSD pairwise comparisons for each treatment group. The within-subjects factor was time (before, during and after treatment). The data were checked for violations of sphericity with Mauchly’s test of Sphericity. If the sphericity was violated (p < 0.05), the Greenhouse–Geisser correction was used. The significance level for ANOVA was set at 5%.

Data were collected from May 2018 to April 2020. Out of the 172 parents eligible for participation, 163 parents filled out questionnaires at T1. One questionnaire was removed because it had more than thirteen missing values on the HAPA items and we considered it as non-reliable. Two questionnaires were detected as outliers and removed from the data using outlier detection for ordered rating scales data (Zijlstra et al. 2013). The flowchart of the data collection (Fig. 3) illustrated that a total of 160 questionnaires were available for statistical analysis at T1, 108 questionnaires at T2 and 71 questionnaires at T3. Of these, 66 parents filled out a questionnaire at all three measurement times. There was a premature stop of the data collection during the course of the COVID-19 pandemic in 2020. The time between T1, T2 and T3 varied.

Descriptive characteristics and sociodemographic variables at baseline are shown in Tables 1 and 2. At baseline, the parents who filled out the questionnaire were mostly mothers 74.7%), 126 parents lived with a partner (82.4%), and 66% of the mothers were categorised as having a low level of education. The age of the mothers ranged from 22 to 48 years with a mean age of 34.2 years (SD = 5.6). Slightly more than half of the children (54.4%) were boys (n = 87), the children had a mean age of 5.2 years (SD = 1.5, range 3–9) and had a mean dmft + DMFT of 8.4 (SD = 2.4, range 3–14). More than half of the children had Dutch ethnicity (56.9%). Most of the children were treated under IVS (77.5%). Reasons for treatment under IVS are presented in Table 1. The children of the parents who filled out all three questionnaires (T1, T2 and T3) were older at baseline (5.5 years, SD = 1.6) compared to the children of the parents who filled out the questionnaire at baseline only (T1) (5.0 years, SD = 1.4, p = 0.046). The questionnaire was filled out by the same parent in 83.0% of the cases at T2 and in 75.8% at T3. The other descriptive characteristics and socio-demographic variables did not differ between parents who only filled out questionnaires at T1 and parents who filled out questionnaires at T1, T2 and T3.

Baseline mean HAPA scores and standard deviations for the total group and comparisons between treatment groups are shown in Table 2. Children in the IVS group were significantly younger than children in the BGT group (5.0 years (SD = 1.4) versus 5.8 years (SD = 1.7), t(156) = 2.76, p = 0.007) and dmft + DMFT was significantly higher in children in the IVS group than in children in the BGT group (9.0 (SD = 2.1) versus 6.1 (SD = 2.1), p < 0.001). There were no differences in gender and ethnic background between children of both groups at baseline. There were no differences between parents of both groups regarding the, marital status, level of education of the mother, brushing frequency of the child, reporting of the ideal brushing frequency, the frequency the parent forgot the brush their children’s teeth, supervised toothbrushing and parental dental visits and parental own brushing frequency (Tables 1 and 2). Furthermore, the mean scores on the HAPA constructs were high and varied from 2.69 (SD = 0.60) action control) to 3.47 (SD = 0.51) (coping self-efficacy). There were no differences in mean HAPA scores between the IVS group and the BGT group at baseline (Table 2).

Repeated measures ANOVA per treatment group with post hoc LSD pairwise comparisons (Table 3) revealed a small main effect of time in the BGT group in action self-efficacy (F_(2,26) = 4.81, p = 0.016, η² = 0.26), namely a decrease from T1 to T2 (p = 0.027) and from T1 to T3 (p = 0.021), and in coping self-efficacy F_(2,28) = 3.37, p = 0.049, η² = 0.19) a decrease between T1-T2 (p = 0.015). In the IVS group, a small main effect of time was observed in action planning (F_(2,94) = 3.22, p = 0.046, η² = 0.06), namely a decrease between T1 and T3 (p = 0.036) and in action control (F_(2,98) = 5.50, p = 0.005, η² = 0.010), namely an increase between T1-T2 (p = 0.012) and between T1-T3 (p = 0.006).