Objectives:
Previous studies reported that S-PRG filler having three layers including a glass-ionomer phase releases 6 different ion species which help promote various bioactive effects. The present study investigated effects of ions released from S-PRG filler on acid resistance of carbonate apatite.
Methods:
S-PRG filler and distilled water (weight ratio:1/1) were mixed, stirred (24h) and centrifuged to prepare liquid containing various ions (TL: treated liquid). Each ion species was quantitated by employing ICP emission spectrometry (ICPS-8000, SHIMADZU CO.) and fluoride ion electrode method (fluoride ion electrode: Model 9609BN, Orion Research; pH/ion meter: Model 720A, Orion Research).
Conventionally-synthesized carbonate apatite (C-AP, 125mg) and TL (7.5mL) were mixed, stirred (37ºC, 24h), centrifuged, rinsed, and dried. The treated C-AP (50mg) and demineralizing solution (10mL, pH5.75) were mixed and stirred (37ºC, 10m). Then Ca and P elements eluted from the mixture were quantitated by ICP emission spectrometry to determine acid resistance of the treated C-AP. For comparison, distilled water (DW) and NaF solutions containing 100ppm fluoride (NaF100) and 1000ppm fluoride (NaF1000) were used in place of TL. Data obtained was statistically analyzed (one-way ANOVA, Tukey's, p<0.05).
Results:
TL was analyzed to contain Al (24.7ppm), B (1402.0ppm), Na (472.1ppm), Si (14.3ppm), Sr (147.1ppm) and F (106.0ppm). Levels of Ca and P eluted from C-AP treated with TL were notably lower (Ca:80.6±0.8, P:28.8±0.4) than those of C-AP treated with DW (Ca:226.8±2.3, P:91.2±1.1) or with NaF100 (Ca:128.8±7.6, P:47.5±3.4), but showed no significant difference compared to those of C-AP treated with NaF1000 (Ca:87.4±3.4, P:31.0±1.0).
Conclusion:
C-AP treated with TL containing approximately 100ppm fluoride exhibited similar acid-resistance results as C-AP treated with 1000ppm fluoride-containing NaF solution. This suggested that both fluoride and other ion species detected in TL acted synergistically on C-AP (i.e. ion percolation and exchange) to result in the increase in acid resistance of C-AP.