Dimensional Stability of an Calcium Phosphate Cement

Objectives:

An experimental calcium phosphate cement (CPC) was developed for endodontic use (root repair and filling, pulp-capping), characterized with regard to dimensional stability in water and compared to commercial products.

Methods:

CPC is a water-based cement composed of tetracalcium phosphate and dicalcium phosphate anhydrate which cures forming hydroxyapatite after mixing with water. For CPC, following different powder/liquid ratios (P:L) were tested: 5:1; 3.6:1; 2.9:1; 2.1:1; 1.7:1. The other materials to be tested were: ProRoot MTA (MTA, Dentsply), Apaxit (AP, Ivoclar Vivadent AG), AH Plus (AH, Dentsply), Endomethason (EN, Septodent). For the study, 30 drill holes of a metal mould (diameter 4mm, depth 6mm) were filled with the materials. Five samples of each material were prepared. All other materials were handled according to manufacturer's instructions. The zero point for the test was defined with a surface laser scanner (UBM, Germany). After storage in water for 0.5, 1, 2 and 3 months surface was characterized again. Differences of averaged surface level describe the shrinkage or expansion of the samples.

Results:

After water storage CPC with P/L 3.6:1, 2.9:1 and 2.3:1 showed slight shrinkage whereas CPC with lower P/L showed increasing shrinkage within the first 2 months. EN showed highest dimensional changes.

 

	Dimension-change [%.10-3] (SD)
Time [month]	CPC P.L=5:1	CPC P:L=3.6:1	CPC P:L=2.9:1	CPC P:L=2.3:1	CPC P:L=2.1:1	CPC P:L=1.7.1	MTA	AP	AH	EN
0.5	119(145)	-10(31)	23(10)	-62(15)	-94(34)	-99(20)	29(35))	-129(72)	-11(15)	457(32)
1	186(152)	-2(31)	32(74)	-42(71)	-70(76)	-132(69)	-27(22)	-74(68)	-144(89)	681(129)
2	111(100)	-55(19)	-15(18)	-12(5)	-156(25)	-219(40)	88(127)	-92(31)	23(16)	1538(275)
3	368(292)	86(72)	-104(48)	-133(28)	-144(34)	-146(80)	69(138)	-109(29)	35(28)	1457(313)

Conclusion:

Within the limits of this study, CPC presents an acceptable dimensional stability, which is comparable with commercial endodontic materials. Further studies has to be conducted on pore size distribution.