Fluoride release, microbial inhibition and microleakage pattern of two orthodontic band cements

To compare, in vitro, the fluoride release, microbial inhibition and microleakage pattern of a conventional glass ionomer cement (Ketac-Cem) and an acid-modified composite (Ultra Band-Lok) for band cementation.

Fluoride release was measured from cement discs (3.0 mm diameter and 1.5 mm thick) at regular intervals over 40 days using a potentiometric method. Microbial inhibition was determined for each cement using an agar diffusion test against one of four different strains of Streptococcus mutans. Thirty pairs of banded third molars (15 banded pairs for each cement) were thermocycled and microleakage determined by a dye penetration method. The depth of microleakage was assessed by an index applied by two examiners independently to photographic records taken of the mid-buccal aspect of each tooth.

The cumulative and daily fluoride release for days 5, 15 and 40 were significantly greater for Ketac-Cem than for Ultra Band-Lok (all p < 0.05). After the initial set, the anti-microbial activity was significantly greater for Ketac-Cem than for Ultra Band-Lok over the following 24 h period for all four strains of S. mutans (all p < 0.05). There was no significant difference between the two cement groups for microleakage at the cement/enamel interface (p = 0.66) but a borderline significance was detected for microleakage at the cement/band interface (p = 0.051).

The fluoride release and anti-microbial activity of Ketac-Cem were greater than that of Ultra Band-Lok. There was no significant difference in microleakage between the cements at the cement/enamel interface but a borderline difference existed between the cements at the cement/band interface.