Table 2: Method overview.

Analysis undertakenGroup 1 (fluoride release/recharge)Group 2 (mechanical properties; elastic modulus/hardness)

Specimen number per material36
Storage mediaDeionized waterDeionized water
Lactic acid pH 4
Analysis times over 18 mth agingBimonthly (0, 2, 4, 6, 8, 10, 12, 14, 16, and 18 mths)24 hrs, 1 mth, 3 mths, 6 mths, 12 mths, and 18 mths
Time elapsed following 18 mth F recharge before recharge analysis2 months24 hours