pH of self-etching cements

Objectives: This study characterized pH vs time for self-etching cements utilizing pH meter and pH paper. Methods:The pH data from 30 seconds to five minutes after mixing was measured for six self-etching cements by pH meter (WTW Sen Tix V).

And the pH data from 30 seconds to one day after mixing was measured for six self-etching cements by pH paper (Type CF #2613991). Six self-etching cements were Unicem Aplicap /3M ESPE, Unicem Clicker/3M ESPE, Maxcem / Kerr, Monocem /Shofu, Embrace WetBond /Pulpdent, and Multilink Sprint/Ivoclar. Results: The pH data of six self- etching cements utilizing pH paper are listed.

Table  pH measured with pH paper vs time of self-etching cements

Time   Unicem Aplicap    Unicem  Clicker      Maxcem        Monocem     Embrace Wetbond    Multilink

30 s    2.23 (0.06)*             2.74 (0.26)              2.29 (0.05)      2.13 (0.06)        2.29 (0.05)                5.52(0.01)

2 m     2.32 (0.05)              2.68 (0.11)              2.39 (0.15)      2.29 (0.23)        2.29 (0.15)                5.52(0.01)

5 m     2.93 (0.30)              3.13 (0.42)              2.32 (0.20)      2.09 (0.06)        2.35 (0.10)                5.55(0.01)

30 m    5.50 (0.13)              5.16 (0.11)              2.64 (0.10)      2.39 (0.20)        2.55 (0.25)                5.73(0.26)

1 h      5.59 (0.16)              5.54 (0.19)              2.67 (0.06)      2.74 (0.10)        2.77 (0.06)                5.63(0.08)

24 h     5.98 (0.03)              6.01 (0.05)              4.82 (0.49)      4.47 (0.07)        2.96 (0.06)                5.62(0.06)

*Means with standard deviations in parentheses (n=3).

At 30 seconds to 5 minutes, the pH data for five self- etching cements (except for Multilink Sprint ) were low (2-3), and strong acid characteristics. After one day, the pH data (2.96-6.01) were different among the self-adhesive cements.

Conclusions:After several minutes of mixing, Unicem Aplicap, Unicem Clicker, Maxcem , Monocem and Embrace WetBond had strong acid characteristics. After one day, pH of Unicem Aplicap and Unicem Clicker indicated approximately neutrality.

Supported in part by a grant from 3M ESPE to Dental Consultants, Inc.