Table 2: Comparison of plaque index (PI), calculus index (CI), gingival index (GI) and bleeding on probing (BOP) between two groups of retainers.

Mean (SD)
Time interval	T0	T1	T2	T3	T4
PI
Group 1	-	0.46 (0.65)	0.7 (0.62)	1.04 (0.66)	1.23 (0.65)
Group 2	-	0.23 (0.51)	0.6 (0.70)	0.9 (0.59)	1.12 (0.59)
p-value	-	> 0.05	> 0.05	> 0.05	> 0.05
CI
Group 1	-	0.12 (0.43)	0.12 (0.43)	0.23 (0.51)	0.38 (0.57)
Group 2	-	0.00 (0.00)	0.15 (0.46)	0.23 (0.43)	0.38 (0.57)
p-value	-	> 0.05	> 0.05	> 0.05	> 0.05
GI
Group 1	-	0.31 (0.55)	0.65 (0.69)	1.04 (0.66)	1.15 (0.68)
Group 2	-	0.15 (0.37)	0.5 (0.51)	0.81 (0.5)	0.92 (0.4)
p-value	-	> 0.05	> 0.05	> 0.05	> 0.05
BOP
Group 1	-	0.08 (0.27)	0.23 (0.43)	0.42 (0.5)	0.5 (0.5)
Group 2	-	0.00 (0.00)	0.19 (0.4)	0.27 (0.45)	0.42 (0.5)
p-value	-	> 0.05	> 0.05	> 0.05	> 0.05

p-values calculated using Mann-Whitney test. Group 1 = FRC. Group 2 = MSW. T0 = baseline. T1 = 3 months after insertion. T2 = 6 months after insertion. T3 = 9 months after insertion. T4 = 12 months after insertion.