MANIPULATION EFFECTS ON FLUORIDE RELEASE FROM CHEMICALLY-CURED AND RESIN-MODIFIED GLASS IONOMERS

Purpose: TO examine the effect of mixing techniques (hand-mixing vs. t rituration) on fluoride release from chemically-cured (Fuji II) and re sin-modified (Fuji II LC) glass ionomer products. Materials and Method s: Fluoride measurements were determined and comparisons made between hand-mixed-type materials that were both hand-mixed (60 seconds) and t riturated (10 seconds). Hand-mixed specimens were made using the manuf acturer's recommended powder/liquid ratio. Triturated specimens of the same material were made using the same powder/liquid ratio. Disk spec imens (5.5 mm diameter, 2 mm thickness; n = 6) were stored in deionize d water for 23 hours to obtain Day 1 solutions. Solutions were also ob tained at 2, 3, 4, 5, 6, 7, 14, 21, and 28 days after fabrication and were changed 24 hours before fluoride concentration was determined usi ng a fluoride ion selective electrode. Daily rates of fluoride release and 28-day cumulative fluoride totals were calculated. Cumulative dat a were analyzed by two-way ANOVA and Scheffe's test (a = 0.05). Daily results were analyzed by the Mann-Whitney U-test. Results: A significa nt difference was observed between materials (P < 0.001). Depending on the kind of material used, the method of manipulation affected the fl uoride release. Data analysis revealed that: (1) Fuji II LC released s ignificantly more fluoride than Fuji II: for both triturated (P = 0.00 5) and hand-mixed (P < 0.005); (2) the triturated Fuji II released sig nificantly more fluoride than the hand-mixed (P = 0.02); and (3) the h and-mixed Fuji II EC released more fluoride than the triturated, but w as not statistically significant (P = 0.16).