The impact of the loss of first permanent molars on the duration of treatment in patients treated with orthodontic space closure and without skeletal anchorage

Table 4 Variables associated with of orthodontic treatment duration (dependent variable) by the univariate and multiple linear regression model

Independent Variables	Univariate model			Multivariate model
Independent Variables	p value	Adjusted p value	CI (95%)	β	R²	Adjusted R²	F test
Number of 1st molar losses	< 0.001*	0.027	0.455–7.099	3.777	0.817	0.774	19.0
Months of missed appointments	< 0.001*	< 0.001*	1.918–3.751	2.834
PAR T0	< 0.001*	0.180	− 0.142 to 0.729	0.293
PAR T1	0.056*	0.174	− 0.304 to 1.619	0.657
Sex	0.045*	0.765	− 6.860 to 5.087	− 0.886
Age at T0	0.013*	0.152	− 0.057 to 0.356	0.140
Remaining Space	< 0.001*	0.288	− 0.042 to 0.137	0.047
Angulation	< 0.001*	0.771	− 1.246 to 0.932	0.157
Dental Arches	< 0.001*
Number of debondings	0.207
Previous Orthodontic Treatment	0.457
Class I, II or III	0.874