579039.fig.004a
(a)
579039.fig.004b
(b)
Figure 4: (a) The effect of 1-hour fluoride recharge on composite hardness after 18 months of aging in lactic acid ph 4 (L.A.) and deionized water (W). (b) The effect of 1-hour fluoride recharge on composite elastic modulus after 18 months of aging in lactic acid ph 4 (L.A.) and deionized water (W).