Abstract:
INTRODUCTION: The open-sandwich technique was proposed
to solve the problem of cervical micro-leakage of deep Class
II composite restorations by making use of the self-adhesive
nature of the glass-ionomers. Recent advances in the properties
of this family of materials may continue to make the technique
relevant today.
AIMS AND OBJECTIVES: The aim of this in vitro study was to
determine the effect of thermocycling, cervical position and the
use of different materials on the cervical microleakage of Class II
open-sandwich restorations.
METHODS: Two hundred standardised Class II cavities with the
cervical margins placed in either enamel (100) or dentine (100)
were prepared in 100 extracted human molars. Ketac Molar, set
with ultrasound (US), Ketac Molar, Ketac Nano and Vitremer were
used in equal groups to restore the cervical boxes, while Filtek
Z250 was used to complete the restorations and also provided a
control group in which the sandwich technique was not used. One
half of each group was subjected to thermocycling. Microleakage
was assessed by measuring the distance of penetration of basic
fuchsin dye along the cervical step.
RESULTS: The open-sandwich technique significantly (p<0.001)
reduced the microleakage otherwise seen in Filtek Z250 when
margins were placed in dentine and thermocycled.
CONCLUSIONS: The use of an ultrasonically cured glass-ionomer
in the open-sandwich resulted in the least microleakage (after
thermocycling) when the cervical margins of Class II restorations
were placed in dentine.
