The purpose of this in vitro study was to evaluate the microleakage of
direct and indirect inlay/onlay systems. Two of the groups investigat
ed have indirect applications only and consist of microfine composites
. The other two groups of inlay/onlay systems have both direct and ind
irect applications and are hybrid composites. Standardized MOD prepara
tions were cut in 60 extracted human premolars. One gingival margin wa
s placed in enamel above the cementoenamel junction (CEJ) and the othe
r was placed in dentine below the CEJ. The inlays were made and luted
according to each manufacturer's recommendation. The restored teeth we
re thermocycled and immersed in a basic fuchsin solution for 24 h. Fol
lowing the mesiodistal sectioning of the specimens, extent of dye pene
tration at the restoration-glass ionomer cement and tooth-glass ionome
r cement interfaces were scored using a stereomicroscope. Both direct
and indirect inlays showed substantial leakage at gingival-dentine mar
gins. However, there was only superficial leakage at enamel margins. C
omparing the overall indirect inlay systems, EOS inlay leaked the most
(P < 0.05). Indirect Brilliant Dentin(R) inlays showed a significantl
y smaller amount of leakage than the other inlay systems. SRIsosit(R)
and Estilux Posterior C VS(R) inlays provided a favourable marginal se
al. In the case of Brilliant Dentin(R) and Estilux Posterior C VS(R),
indirect inlays leaked more than direct inlays. Generally, no signific
ant difference was observed between the interfaces evaluated in microl
eakage performance.