one year evaluation of microleakage of cavity varnishes

ABSTRACT

The study was conduced to evaluate the effect of storage of amalgam restorations [from 1 week up to 1 year] lined by different types of varnish. Sixty freshly extracted human teeth were selected and stored in normal saline. Black's class V cavity preparations were made in the middle third of both lingual and buccal surfaces of each tooth. The teeth were randomly divided into three groups of twenty teeth each [40 restorations] Group I with no liner, Group II with Copal varnish and Group III with Silver varnish [Amalgam Liner, VOCO Germany]. The teeth were restored with a high copper dental amalgam, then the restored teeth were aged in normal physiological saline at 37 C. each group was further divided into 4 subgroups according to the time of aging [1 week, 3 months, 6 months and 1 year]. The teeth in subgroup A of each group were aged for one week, for subgroup B the teeth were aged for 3 months, subgroup C for 6 months and finally subgroup D for one year. The teeth were then thermocycled, longitudinally sectioned and dye penetration was recorded by a steriomicroscope. Microleakage, in general, significantly decreased with aging between the one- week and the one-year intervals for all groups. The silver varnish groups demonstrated significantly less microleakage when compared with the copal varnish and no varnish groups at the one-week groups. This decrease in dye penetration was insignificant in the 3 month, 6 month and one year group