Table 2.

Linear regression models: association between hypodontia and dental age using Dutch standards

	Model 1			Model 2			Model 3
	β	95 % CI	P value	β	95 % CI	P value	β	95 % CI	P value
Method 1a
Hypodontia
No (ref.)	0	–	–	0	–	–	0	–	–
Yes	−0.46	(−0.65,-0.27)	<0.05	−0.36	(−0.52,-0.20)	<0.05	−0.37	(−0.53,-0.21)	<0.05
Method 2b
Hypodontia
No (ref.)	0	–	–	0	–	–	0	–	–
Yes	−0.57	(−0.76,-0.38)	<0.05	−0.52	(−0.68,-0.35)	<0.05	−0.52	(−0.69,-0.36)	<0.05

Model 1 is the crude dependence of dental age on the hypodontia; Model 2 was additionally adjusted for age, gender, and study population; and Model 3 was adjusted for variables used in previous model and additionally for ethnicity and maternal age at birth of a child

β regression coefficients, CI confidence interval, ref. reference

Dental age was calculated if both matching mandibular teeth were missing by scoring them: ^aas a developmental stage calculated from regression equations developed by [30]; ^bas a developmental stage of the (left) matching maxillary tooth