. 2021 Oct 15;18(20):10850. doi: 10.3390/ijerph182010850

Table 3.

Multiple linear regression models as the SCR of total dental receipts an outcome variable in FY2018.

Model 1	(R² = 0.4658, adj-R² = 0.4285)				95% CI
	Coef.	Std. Err.	t	p	low	high	vif
Dentists	32.82	9.30	3.53	0.001	14.07	51.57	1.28
Dental technician	−21.86	11.33	−1.93	0.06	−44.72	0.99	1.21
Prefectural income per capita	6.48	2.69	2.41	0.020	1.07	11.90	1.07
const.	57.75	9.53	6.06	<0.001	38.52	76.97
Model 1_a	(R² = 0.5107, adj-R² = 0.4641)				95% CI
	Coef.	Std. Err.	t	p	low	high	vif
Dentists	36.85	9.23	3.99	<0.001	18.22	55.49	1.27
Dental technician	−20.68	10.99	−1.88	0.067	−42.86	1.50	1.07
Prefectural income per capita	10.40	3.28	3.17	0.003	3.78	17.01	1.97
Dentist × Prefectural income per capita §	−19.52	9.94	−1.96	0.056	−39.59	0.54	2.03
const.	101.46	3.71	27.38	<0.001	93.98	108.94
Model 2	(R² = 0.3939, adj-R² = 0.3516)				95% CI
	Coef.	Std. Err.	t	p	low	high	vif
Dental clinics	57.03	21.36	2.67	0.011	13.97	100.10	1.43
Dental laboratory	13.12	39.32	0.33	0.74	−66.19	92.42	1.06
Prefectural income per capita	7.21	2.99	2.41	0.02	1.19	13.24	1.39
const.	41.94	11.28	3.72	0.001	19.18	64.69
Model 2_a	(R² = 0.4736, adj-R² = 0.4234)				95% CI
	Coef.	Std. Err.	t	p	low	high	vif
Dental clinics	85.91	23.17	3.71	0.001	39.16	132.67	1.89
Dental laboratory	−31.92	41.16	−0.78	0.442	−114.98	51.15	1.30
Prefectural income per capita	12.41	3.49	3.56	0.001	5.37	19.45	2.13
Clinics × Prefectural income per capita §	−50.09	19.87	3.56	0.016	−90.18	−9.99	2.98
const.	100.57	7.31	13.76	<0.001	85.82	76.97
Model 3	(R² = 0.5296, adj-R² = 0.4813)				95% CI
	Coef.	Std. Err.		p	low	high	vif
Dentists	21.89	9.99	2.19	0.034	1.74	42.04	1.54
Dental hygienist	14.26	6.06	2.35	0.023	2.03	26.49	1.69
Dental technician	−34.77	12.09	−2.88	0.006	−59.17	−10.38	1.31
Prefectural income per capita	8.96	2.78	3.22	0.002	3.35	14.56	1.52
const.	46.43	10.41	4.46	<0.001	25.43	67.44
Model 3_a	(R² = 0.5799, adj-R² = 0.5287)				95% CI
	Coef.	Std. Err.		p	low	high	vif
Dentists	25.28	9.74	2.60	0.013	5.62	44.95	1.60
Dental hygienist	15.29	5.88	2.60	0.013	3.41	27.16	1.74
Dental technician	−34.21	11.55	−2.96	0.005	−57.53	−10.89	1.35
Prefectural income per capita	13.26	3.27	4.06	<0.001	6.67	19.86	2.29
Dentists × Prefectural income per capita §	−20.22	9.33	−2.17	0.036	−39.06	−1.38	1.97
const.	88.57	6.05	14.63	<0.001	76.34	100.80

FY: fiscal year, Coef: coefficient, Std. Err: standard error, CI: confidence interval, vif: variance inflation factor, SCR: Standardized Claim Ratio, JY: Japanese yen, adj-R2: adjusted R2, const: constant term, §: interaction term. All data were centralized to avoid multicollinearity. Dentists, dental hygienist, dental technicians, dental clinics, and dental laboratories are the number per 1000 people.