表 3.

术前、术后1年、术后2年牙髓钙化指数(PCI)1~4级的分布

Percentage of pulp calcification index (PCI) from level 1 to 3 before pulpotomy operation, 1-year and 2-year follow up

Level of PCI		Before operation (PCI0)			1-year follow-up (PCI1)			2-year follow-up (PCI2)
		Cases	Percentage		Cases	Percentage		Cases	Percentage
n=36, *P < 0.05, by rank sum test, the PCI difference among the three groups and between every two groups is statistically significant.
1	No calcification	12	33.3		0	0%		0	0
2	The root canal images become thinner but all of them exist	22	61.1		22	61.1*		16	44.4*
3	Part of the root canal images disappear	2	5.6		13	36.1*		18	50.0*
4	All of the root canal images disappear	0	0		1	2.8*		2	5.6*