The impact of premature birth on dental maturation in the permanent dentition

Abstract

Objectives: To evaluate tooth development and calculate dental maturity score in prematurely born children and to compare the findings with full-term born children.

Material and methods: Nine-year-old preterm children were selected from the Swedish Medical Birth Register. One group consisted of 36 extremely preterm children (born before week 29), and the other included 38 very preterm children (born during weeks 29 to 32). Panoramic radiography was performed on each child and the preterm children were compared with 42 full-term born children. Five observers independently assessed the tooth development stages for all teeth in the left mandible (31-37) on the panoramic radiographs according to the method described by Demirjian et al. (Hum Biol 45:211-227, 1973). Data from tooth development stages were compiled and converted into a dental maturity score for each group. Kappa values were calculated for intra- and inter-observer agreement.

Results: When the different development stages for each individual tooth were compared, all observers presented a significant delay in the maturity of tooth 37 for the extremely preterm group (p ≤ 0.002). The extremely preterm group had a significantly lower dental maturity score than the full-term group, as assessed by each observer (p ≤ 0.006). Kappa values for inter-observer agreement varied between 0.31 and 0.71 depending on tooth and intra-observer agreement was between 0.16 and 1.0.

Conclusions: At age 9, the extremely preterm children had a general delay in tooth development.

Clinical relevance: The increased survival rate of extremely preterm babies adds a new group of children to society. Dental clinicians should be aware that the delay in tooth development could impact the timing of orthodontic diagnostics and potential treatment.

Keywords: Dental maturation; Panoramic; Preterm birth; Radiography; Term birth; Tooth development.

Fig. 1

Panoramic radiograph from one of the included individuals. Teeth 31–37, which are marked with a cross, were assessed according to Demirjian et al. [15]. The criteria for the assessment of different stages varied from the beginning of calcification of crown to apical root apex completely closed (stages A–H). In Fig. 1, for example, tooth 31 was assessed as stage H and tooth 37 as stage D. If a tooth appeared to be between stages, the earlier stage was chosen

Fig. 2

The distribution of development stages within the three groups for tooth 37 for one observer’s assessment. According to Demirjian et al. [15], the tooth development could be rated on a scale from the beginning of calcification of crown to apical root apex completely closed (see Table 1 for description of stages A–H). In all three groups, tooth 37 were classified to be in development stages D, E, or F. In stage D, the crown formation is completed down to the cemento-enamel junction. In stage E, the root length is still less than the crown height and in stage F, the root length is equal to or greater than the crown height. When comparison between groups were made, it was found that tooth 37 was significant in more undeveloped stages in both the extremely preterm group (EPT) (p < 0.000) and in the very preterm group (VPT) (p = 0.016) compared to the full-term group (FT)