Table 3. Segmented regression of the interrupted time-series analysis of dental cost during the period of the study.

Groups	Time		Policy change		Time after changed		DW	R2
	β	P valuea)	β	P valuea)	β	P valuea)
All outpatients	0.0027	<0.001	0.1759	<0.001	−0.0022	<0.001	1.9995	0.1246
Gingivitis	0.0014	<0.001	0.4736	<0.001	−0.0007	<0.001	1.9979	0.1164
Advanced periodontitis	0.0020	<0.001	0.1470	<0.001	−0.0015	<0.001	1.9997	0.1165

β: time-series coefficients, DW: Durbin-Watson statistic.

^a)Statistical significance (P<0.05).