The Challenge of Early Prevention of Periodontal Diseases in Japan

The high prevalence of dental disease makes it an important set of diseases from the public health standpoint. In Japan, since the 1980s, educational campaigns by dental health practitioners spearheaded by the Japan Dental Association and the Ministry of Health, Labor and Welfare (MHLW) together with the widespread use of fluoride preparations have dramatically reduced the proportion of 15–19 year-olds with caries (decayed, filled teeth) from 94.9% in 1993 to 47.1% in 2016. ¹ The proportion of those with untreated caries in permanent teeth have also been reduced from 51.2% in 1993 to 19.6% in 2016. ¹

Let us now consider the current periodontal health situation. In 2016, only 6.1% of people aged 15–19 years have periodontal pockets measuring ≥4 mm. However, the proportion of people aged 20–24 years with periodontal pockets measuring ≥4 mm is 25.7%, a dramatic rise compared with the rate for those in people aged 15–19 years. It is also concerning that this proportion has risen rapidly in recent years from 9.5% in 2005 to 25.7% in 2016. ¹ Attention is not typically focused on periodontal disease until middle age or later, when its symptoms become apparent, but these data indicate the importance of periodontal health management in younger generations. Although severe periodontitis is rare in young people, gingival bleeding is often seen. In an MHLW survey, 30.6% of those aged 15–19 complained of gingival bleeding, as did 36.5% of those aged 17–19 in our survey. ² That is, approximately one in three late teens exhibits an early symptom of periodontal disease.

The risk of gingival bleeding is found to be increased with lower daily tooth brushing frequency and shorter tooth brushing time. Multivariate analysis showed that for people who brushed their teeth once a day or less, the risk of gingival bleeding was 2.4 times that for those who brushed their teeth three or more times a day, and that for those who brushed their teeth for a minute or less, the risk was 1.6 times that for those who brushed them for 4 min or more. ³

In recent years, it has become clear that periodontal disease is associated with a range of systemic diseases. ⁴ Attention has focused primarily on these associations in adulthood; however, it was found that gingival bleeding was closely linked to systemic diseases, asthma and otitis media/externa in late adolescence. Both asthma and otitis media/externa were independent risk factors for gingival bleeding. ²

Unlike caries, periodontal disease does not typically appear until adulthood. The proportion of people who met the goals of the 8020 movement to retain twenty of one’s own teeth up to the age of 80 promoted by the Ministry of Health and Welfare (MHW) and the Japan Dental Association rose to more than 50%. As tooth loss because of caries has declined, the prevention and management of periodontal disease has now become an important issue for maintaining oral and general health, and this will require thorough measures to improve periodontal health status in younger generations.