Table 4.

Dental maturity score within the groups extremely preterm (EPT), very preterm (VPT), and full-term (FT), as calculated from the 5 observers’ assessments of 7 left mandibular teeth (teeth 31–37) according to the method of Demirijan et al. [15]

	Mean dental maturity score (SD)
Observer	EPT	VPT	FT	Group differencesa, p values
1	86.7 (7.2)	89.1 (4.6)	91.1 (4.6)	EPT/FT 0.003EPT/VPT NSVPT/FT NS
2	81.9 (8.9)	85.2 (6.7)	88.1 (6.0)	EPT/FT 0.001EPT/VPT NSVPT/FT NS
3	83.7 (7.8)	86.4 (5.2)	89.1 (4.4)	EPT/FT 0.000EPT/VPT NSVPT/FT NS
4	84.6 (8.5)	86.7 (5.6)	89.0 (4.3)	EPT/FT 0.006EPT/VPT NSVPT/FT NS
5	82.3 (7.4)	86.6 (5.1)	88.3 (4.3)	EPT/FT 0.001EPT/VPT NSVPT/FT NS

^aNS not significant