Table 8.

Multiple linear regression analysis with change of CAL as the dependent variable in the subjects with high oxidative status (>380 CARR U) (N = 22).

Variables	B (95% CI)	β	P value
Intercept	1.622 (0.650, 2.593)	—	0.002
PPD (mm) at baseline	−0.718 (−1.236, −0.200)	−0.539	0.009
ΔPCR (%)	−0.011 (−0.027, 0.006)	−0.251	0.193

We used backward elimination method with a P > 0.1 threshold for exclusion to construct the Model. The candidate variables for the model were ΔTeeth present, PPD at baseline, and ΔPCR. The F-statistic was 5.012 (P value was 0.018), the R-square was 0.345, and the adjusted R-square of the model was 0.276. The variance inflation factor was <5 and condition index was <15.

Δ represents differences (value at follow-up minus value at baseline).

N: number; CI: confidence interval; B: unstandardized regression coefficient; β: standardized coefficient; PPD: probing pocket depth; CAL: clinical attachment level; PCR: plaque control record; and CARR U: Carratelli units.