Marginal closure of composite restorations with the gingival wall in cementum/dentin.

The marginal leakage of five adhesive composites placed in class V cavities extending into the root was examined by immersing the specimens in China ink after thermal cycling. Clearfil F II-initial bond, Silar-Scotch Bond, and Miradapt-D21 materials did not show leakage when all cavity walls were totally etched, whereas they showed leakage at the dentinal/cemental wall when only enamel was etched. In either conditions Clearfil F II-New Bond materials did not show leakage and Miradapt material showed leakage. Manipulative variables affected the seal of Clearfil F II-New Bond materials. Insertion later than 3 minutes after applying New Bond material induced microleakage. The use of pressure under a matrix did not affect the seal. Maintaining dryness for 3 minutes at the etched dentinal/cemental margin and 1 minute at the etched enamel margin was sufficient to prevent microleakage. Finishing before the initial polymerization of the composite or lining the whole axial wall caused microleakage.