rel="nofollow" href="#ulink_f3e5b045-8f2e-58e3-b00b-846bddfddc87">11, 38, 39]. On the basis of data from 20,000 schoolchildren aged 5–16 years in the USA, it was established that the predominant susceptible tooth sites in low dentine carious lesion individuals (DMFS <5) were pits and fissures (95%). The proportion of approximal surfaces and smooth surfaces increased with an increase in mean DMFS score in this age group. In high-dentine carious lesion individuals (DMFS >25), the proportion of dentine carious lesions was about 20% for smooth surfaces, 30% for approximal surfaces, and 50% for pits and fissures [39].
Is there also a hierarchy in dentine carious lesions by tooth type? On the basis of the findings of the same US study, it could be concluded that occlusal surfaces of first molars and buccal pits of lower first molars were the most carious lesion-susceptible type of tooth and tooth surface. If all the first molars are affected, then a high probability exists that the second molars will be affected. The occlusal surfaces of the second molars and the buccal surfaces of the lower second molars are the second most susceptible sites for dentine carious lesion development in children with a low DMFS count. Smooth surfaces on the lower anterior region are least susceptible. A New Zealand birth-cohort study confirmed that the first followed by second permanent molars are most affected by dental caries over a period of 38 years [40].
All in all, pits and fissures in occlusal and pits in buccal tooth surfaces appear to be the most vulnerable sites for dentine carious lesions in the permanent teeth of children and adolescents. In children at high-caries risk these sites may need extra protection to keep them healthy.
Table 5. Trends in the prevalence of cavitated dentine carious lesions and in mean DMFT scores in adolescents, young adults, and 35- to 44-year-olds, and number of sound teeth over decades in a number of countries (data from Frencken et al. [30])
Table 6. Median mean DMFT scores and range interval among 35- to 44-year-olds, proportion of D-component and range interval by category of country income, using WHO Data Bank data from 2000 to 2015 (data from Frencken et al. [30])
Prevalence and Extent of Carious Lesions in Adults and the Elderly
Using the data of the WHO database, the median mean DMFT score among 35- to 44-year-old adults was high in the high-income group (13.5) and low in the low-income group (3.1; Table 6). Unfortunately, only a small number of countries was included in the low-income group. The mean percentage of the D-component was low (9.6%) in the high-income group and high (53.6%) in the low-income group.
Although there have been few trend studies, they show a clear picture. The mean number of teeth present among 50-, 60-, and 70-year olds from Sweden increased from 21.5 to 26.1 among 50-year olds and from 13.3 to 20.7 among 70-year olds between 1973 and 2003 [41]. Among 50-year-old Swedish women, the mean number of teeth increased from 14.6 in 1968/69 to 27.3 in 2004/05. The percentage of edentulous women decreased from 18.2 to 0.3 between 1968/69 and 2004/05 [42]. This pattern has also been reported in the UK, Canada, and Australia [43].
The prevalence of root carious lesions in subjects aged over 60 years in Japan was 39% in 2006, with poor oral hygiene and a low salivary flow rate being potential risk factors [40]. More recently, in southern Brazil, approximately 36% of dentate individuals had carious lesions and/or restorations that affected, on average, 5.0 teeth [41]. In an older age group of over 80-year-old Swedish elders, untreated coronal dentine carious lesions were present for between 36 and 56% of the subjects, while between 54 and 75% had untreated root carious lesions [42]. A review on this topic is available from Tonetti et al. [44].
The fact that people are getting older with more natural teeth than in previous times increases the risk for carious lesion development, both in crown and root surfaces, because of an increase in the number of teeth and improvement in living conditions. This risk implies that adequate care needs to be organised on the basis of realistic treatment options that include the possibility to deliver care at home and in institutions where many elderly people remain for longer. This implies that the care, including restorative treatments, needs to be mobile. An example of such an approach is atraumatic restorative treatment (ART) [45, 46].
Challenges
Dental caries is a behavioural/life-style disease which is preventable in nature through diet (sugar-free consumption) control and daily plaque removal with a toothbrush and fluoride toothpaste. Despite being preventable, dental caries is widespread and untreated dentine carious lesions in permanent and primary dentitions are ranked number 1 and 10, respectively, on the list of most prevalent medical diseases and conditions [47].
Pits and fissures in occlusal first molars and pits in buccal mandible first molars are the tooth types and sites that are the most susceptible for developing dentine carious lesions. In children at high risk for carious lesion development, these tooth types and sites need to be monitored well.
Progress has been made in oral health over the last 3–4 decades, but the extent to which the reduction in prevalence and severity of dental caries is applicable to countries around the world is unknown as many countries do not carry out epidemiological surveys or do not publish the results in the English-language dental literature. However, monitoring and comparing trends in caries prevalence and severity requires studies to have the same outcome measures and use the same assessment instruments.
Considering the need and importance for monitoring dental caries over time, only validated carious lesion assessment indices/systems should be used. Not all currently used indices/systems have sufficient validation. The CAST instrument is an exception, but it requires further testing for its applicability in different age groups.
Generally speaking, dental caries is an age-related and a life-long disease. Despite progress made in improving oral health, the fact that people are living longer and that more teeth remain at risk at old age than before does not reduce the burden of dental caries in society. This conclusion calls for the introduction of a massive behavioural/preventive programme that targets parents and dental/medical professionals, and should start at mother and child health care centres and continue throughout the primary educational system. Dental practitioners should leave their comfort zone of the dental surgery and make themselves available for providing care at the community level, while oral health care financial systems should allow for a gradual shift from predominantly rewarding curative care (damage repair) to preventive and promotional oral healthcare.
References