Dental caries is a complex non-communicable disease with a high prevalence across the life span (Pitts et al.
2017). While some determining factors are not readily modifiable, such as genetics and socioeconomic status, sugar reduction and oral hygiene are lifestyle and behavioural factors that can be addressed early in life. In this cohort of Swedish-born children to relatively well-educated parents, tooth brushing was introduced at an early age; 95% of the parents had started to brush their children teeth at the age of 1 year (Boustedt et al.
2018). Furthermore, the use of 1000 ppm fluoride-containing toothpastes was practically mandatory as very few non-fluoride, or low-fluoride products, were available in Sweden at the time of the study. In this context, our main finding of tooth brushing frequency and the cooperation with its performance during early childhood as discriminating factors for future caries development was interesting. The results confirmed findings from previous studies in Scandinavia (Wigen and Wang
2015,
2017). Although a regular mechanical disruption of the oral biofilm is a key event for the maintenance of oral health (Twetman
2018) it should be underlined that tooth brushing in the absence of fluorides has failed to show a benefit in terms of reducing the incidence of dental caries (Hujoel et al.
2018). The toothbrush is probably the most convenient and accepted tool to bring fluoride into the oral cavity (Marinho et al
2009) and, needless to say, when brushing is infrequent or associated with problems, the child will not benefit from the topical mechanisms of fluoride action. Our results suggest that the oral biofilm should be exposed to fluoride ions more often than once per day to maximize its caries-preventive effect and this knowledge must be emphasized to parents. Likewise, parents encountering difficulties to perform the tooth brushing should be offered empowerment and hands-on training by oral health personnel. Such preventive measures have the potential to be cost-effective; toothpaste with fluoride is close to an ideal public health method that is convenient, inexpensive, culturally approved and widespread (Burt
2008) and improved brushing skills can spill over to siblings and relatives. Moreover, it has been shown that a favourable oral health behaviour established early in life is stable through the preschool years (Wigen and Wang
2014). The rational to analyse the tooth brushing behaviour in relation to the mode of delivery was our recent finding that the 5-year-olds delivered with caesarean section displayed a 2-time elevated risk of having caries (Boustedt et al.
2018). We found, however, no significant differences in the tooth brushing habits that could help to explain the elevated caries prevalence compared to those that were delivered vaginally.
The prevalence of caries in this cohort was low from an international perspective with a mean dmft value of 0.44 (SD 1.20). It is, however, likely that the true prevalence was somewhat underestimated as bite-wing radiographs were used on individual indications only when caries was suspected. Most importantly, preschool children with manifest caries in their primary dentition display an increased risk to develop caries in the permanent dentition (Mejàre et al.
2014). Thus, preventive measures should be intensified prior to the eruption of the first permanent molar and the present study highlights the importance of emphasizing twice daily assisted brushing with fluoride toothpaste. In particular, problems to perform brushing must be addressed in a systematic and practical way. We believe that an improved brushing behaviour is achievable in most families with preschool children and clearly a less demanding behaviour change than sugar reduction. This does not mean that diet counselling should be overlooked but may be delivered as a second step when optimal tooth brushing with fluoride toothpaste, based on high quality evidence, is secured.
In conclusion, this prospective study showed that caries prevalence at 5 years was significantly related to tooth brushing less than twice daily during the preschool years as well as to difficulties to perform the procedure. Health professionals should, therefore, give special attention and assist parents to improve and optimize their tooth brushing behaviour during the preschool years.