Anatomy

Deciduous teeth possess a much smaller enamel and dentin thickness than permanent teeth ( Fig. 22.1 ). Together with the lower mineral density and more voluminous dentinal tubules this leads to a relatively fast caries progression compared with permanent teeth.1 Moreover, occlusal and/or approximal pulp processes will be reached and affected by the caries process much faster than in permanent teeth.2

As a consequence, the “treatment window” for non-, micro-, or minimally invasive techniques in deciduous teeth is narrower in comparison to permanent teeth. Especially deep dentin caries (ICDAS 5 and 6) is often accompanied by pulpal complications and, therefore, pediatric dentists sometimes even prefer a “preventive” pulpotomy over less invasive approaches. This ensures a rather high success rate as subsequent pulp necrosis is almost avoided. More conservative, minimally invasive options run a higher risk of further caries progression and subsequent pulpal necrosis, often acute pain, abscess, or a fistula, which result in an extraction as the final outcome.

Epidemiology

Caries epidemiology has been described thoroughly in Chapter 8 and certain aspects for pediatric dentistry are emphasized in Chapter 21. Some statements, being important for this chapter, are made below.

• Early Childhood Caries ( Fig. 22.2 ) seems to be a rising problem in many places around the globe.3–7

• Since 1970, DMFT levels dropped by about 90% in 12-year-olds.2,8–13

• During the past 30 years, caries reduction in deciduous teeth was less pronounced in many countries and has decreased by 40%–50%.9,12

• Caries experience is somehow “polarized,” meaning that a small proportion of children is severely affected.14

• In contrast to the fast progression through outer and inner enamel in deciduous teeth, caries progresses much more slowly in permanent teeth, especially in older age groups.15

Not only inter-individual differences can be observed in young children. Also on the tooth and surface levels, caries progression shows different rates compared with those in the permanent dentition. Due to excellent follow-up possibilities using bitewing radiographs, this is best examined for approximal surfaces.15 As pointed out above, caries progresses much more slowly in permanent teeth, especially in older age groups ( Table 22.1 ).

Function and Longevity

Primary teeth are deciduous and have a very limited time of function. On the one hand children are often afraid of dental treatment and prefer the most invasive interventions; on the other hand, it is mostly irrelevant in what condition a primary tooth exfoliates, as long as the space for its successor is retained and no pain or distress was caused. Thus, the pediatric dentist has a difficult decision to make, between less invasive approaches which often require increased preventive efforts by the patients and their parents or, alternatively, more aggressive restorative options. Nonetheless, restored primary teeth are not the beginning of a life-long restorative cycle as in “permanent” teeth, but an adequate, temporary solution until exfoliation and the eruption of the caries-free successors.14

Erupting Permanent Teeth

Permanent teeth are supposed to have a much longer period of function. During that course of time they change considerably with age, especially during eruption and the first years thereafter. Due to alternating de- and remineralizing episodes, surface enamel matures post-eruptively. Hereby, mineral quality is improved and solubility is lowered.16 Due to the life-long activity of the odontoblasts, the pulp recedes, the dentin tubules obliterate and dentin also acquires a higher degree of mineralization. Thus, caries progresses faster in enamel and dentin of newly erupted permanent teeth in children and adolescents than in adults.

Buccal Surfaces

Generally, in most children, initial noninvasive interventions including oral health education are needed to reduce caries risk. For smooth-surface caries lesions mostly developing adjacent to the gingival margin, arrest can be quite easily accomplished by brushing with fluoride toothpaste, whereby the cariogenic biofilm is removed and remineralization in enamel is enhanced. The former chalky white caries lesions appear shiny and hard again, and signs of gingivitis will disappear ( Fig. 22.4 ). Later these caries lesions will be situated ca. 1–2mm above the gingival margin, since the inflammation process in the marginal gingiva is now under control and the gingiva has subsequently recessed.