Table 3.

Comparison of mean dentinal tubule occlusion scores between before and after acid challenge in each group using Student Paired t-test.

Groups	Time	N	Mean	SD	Mean diff	P-value
Group 1	Before	20	4.1	0.64	−0.15	0.08
	After	20	4.25	0.64
Group 2	Before	20	4.55	0.69	−0.25	0.02*
	After	20	4.8	0.41
Group 3	Before	20	2.5	0.69	−1.05	<0.001*
	After	20	3.55	0.76
Group 4	Before	20	1.55	0.61	−0.3	0.01*
	After	20	1.85	0.67