A total sample of 501 subjects was obtained, with 234 Italians and 267 Spanish parents. All the parents approached for enrollment in the study consented to participate, reaching a 100% participation rate. Most of the parents in both countries were mothers, under the age of 40 years old, with a medium-high family income. The only statistically significant demographic factor was that Spanish parents revealed a higher level of education, compared to Italian parents (p < 0.001). Details of sociodemographic characteristics are described in Table 1.
TABLE 1 Comparison of parents’ demographic characteristics in Spain (N=267) and Italy (N=234)
*Statistically significant difference.
†Spain: one participant didn’t respond.
§Italy: five participants didn’t respond
¥Spain: three participants didn’t respond. Italy: seven participants didn’t respond.
^Spain: sixteen participants didn’t respond. Italy: twenty-one participants didn’t respond.
Regarding dental experience, although the majority of Spanish and Italian children were calm and cooperative during previous restorative treatment, 19.2% of Spanish children and 23.7% of Italian children required advanced behavior management techniques. Use of GA was significantly higher in Spain compared to Italy (p < 0.001), while use of N2O was higher in Italy than in Spain (p < 0.001).
When assessing overall aesthetic acceptability of SDF staining, it was more accepted among Italian parents compared to Spanish parents, resulting in a statistically significant difference for both anterior and posterior locations (p < 0.001). Only 41.8% (95% CI, 32.1 to 53) of Spanish parents, compared to 65.4% (95% CI, 59.3 to 71.1) of Italians, considered staining on posterior teeth aesthetically “acceptable” or “somewhat acceptable”. As for anterior teeth, only 17.2% (95% CI, 10.7 to 25.6) of Spaniards reported a positive acceptability score, compared to 19.3% (95% CI, 14.2 to 24.4) of Italian subjects. These results confirm a statistically significant association, with a higher acceptance level for posterior teeth (p < 0.001) in both populations. Figure 1 shows the percentage of overall SDF acceptability on anterior and posterior teeth in Spain and Italy.
In a more specific analysis, parents’ attitude to choose SDF treatment on anterior and posterior teeth was evaluated according to child’s behavior. Comparative analysis assessed that acceptability was lower in Spain compared to Italy for each scenario of cooperation on both locations (all ps < 0.001), except for the ‘cooperative’ scenario on anterior teeth. Decrease in child cooperation was not clearly related with a progressive increase in SDF acceptability in Spain, since mean acceptability scores remained constant overall. On the other hand, it was observed an evident increase in mean acceptability levels among Italian parents as barriers to conventional treatment increased. Finally, for each scenario of collaboration both Spanish and Italian parents were more likely to choose SDF on less visible location, compared to anterior teeth (p < 0.001). Figure 2 reports acceptability mean scores on anterior and posterior teeth for each collaboration scenario of the child in Spain and Italy.
Linear mixed model corroborated that SDF parental acceptability varied according to country, location, and scenario. Mean acceptability rating decreased − 0.50 score unit from Italy to Spain (p < 0.001). Both Spanish and Italian parents revealed a higher level of acceptance on less visible location, compared to anterior teeth (p < 0.001). Regardless of tooth location, Spanish and Italian parents exhibited a negative trend on SDF acceptability in absence of significative barriers to conventional restorative treatment (child collaborating or at most crying). A positive profile of parental acceptability emerged in case of challenging behavior (child kicking or screaming) and if advanced behavior management techniques would be required (physical restraint, N2O, oral sedation, GA). The level of acceptability increased by 0.49 points from the ‘cooperative’ to the ‘non-cooperative’ scenario (p < 0.001), irrespective of the country variable. Results of multilevel analysis are reported on Table 2.
TABLE 2 Comparative multilevel results: effects of random intercept, country, location and scenario on overall acceptability score in Spain and in Italy
SE: standard error
p: level of significance
CI: confidence interval
When introducing demographic factors as third covariate, median ratings of acceptability showed a downward trend in Spain compared to Italy. Each demographic sub-group of both populations –– mothers and fathers, ≤ 40 years old and > 40 years old, ≤ secondary school and > secondary school, ≤ 28.000 euros per year and > 28.000 euros per year ––accepted more SDF on posterior teeth, rather than anterior teeth (p < 0.001). Parental acceptability was not significatively affected by demographic factors in Italy. On the other hand, Spanish older parents showed a higher level of SDF acceptability on posterior teeth (p = 0.005). Furthermore, a significant association was observed between family income ≤ 28.000 euros per year among Spanish parents and increased SDF acceptance on anterior teeth (p = 0.009). Table 3 shows results of SDF acceptability stratified by parental gender, age, education, and income in Spain and Italy.
Table 3
Parental acceptability of SDF according to gender, age, education, and income in Spain and in Italy
| Spain | Italy | P = Mann-Whitney |
| Median (IQR) | Median (IQR) | |
Gender Mother | n. 192 | n. 161 | |
Posterior teeth | 2 (2) | 3 (2) | < 0.001* |
Anterior teeth | 1 (1) | 2 (1) | 0.007* |
Father | n. 74 | n. 73 | |
Posterior teeth | 2 (2) | 3 (1) | < 0.001* |
Anterior teeth | 1 (1) | 2 (1) | 0.003* |
Age ≤ 40 years-old | n. 114 | n. 84 | |
Posterior teeth | 2 (2) | 3 (2) | < 0.001* |
Anterior teeth | 1 (1) | 2 (1) | < 0.001* |
> 40 years-old | n. 153 | n. 145 | |
Posterior teeth Anterior teeth | 3 (1) 1 (1) | 3 (2) 2 (1) | 0.001* 0.086 |
Educational level ≤ secondary school | n. 51 | n. 116 | |
Posterior teeth | 2 (2) | 3 (2) | 0.702 |
Anterior teeth | 1 (1) | 3 (2) | 0.952 |
> secondary school | n. 213 | n. 111 | |
Posterior teeth | 2 (2) | 3 (2) | < 0.001* |
Anterior teeth | 1 (1) | 3 (2) | < 0.001* |
Family median income per year (euro) ≤ 28.000 | n. 102 | n. 94 | |
Posterior teeth | 2 (2) | 3 (2) | 0.021* |
Anterior teeth | 1 (2) | 2 (1) | 0.328 |
> 28.000 | n. 149 | n. 119 | |
Posterior teeth | 2 (2) | 3 (2) | < 0.001* |
Anterior teeth | 1 (1) | 2 (1) | < 0.001* |
*Statistically significant difference. |
IQR: Interquartilic Range |