Influence of Closed Sandwich Technique on Marginal Seal of Class II Restorations with Different Substrates using LED Curing

Abstract

This study was done to evaluate the microleakage at the tooth restoration interface
in different substrates when glass ionomer was used as a base which covered by a
veneer of resin composite, as closed sandwich technique, with light -emitting diode
(LED) curing.
Eighty Class II cavities were prepared in mesial and distal of extracted molars,
mesial cavities with gingival margins in enamel (E) and distal cavities with gingival
margins in dentin(D), were divided into four main groups (G)s, each group was
subdivided into GE and GD of ten cavities for each and filled as follows:
GI each cavity of GIE & GID was filled with composite and cured with halogen
light curing unit (H), GII each cavity of GIIE & GIID was filled with glass ionomer
lining and composite and cured as GI, Group III each cavity of GIIIE & GIIID was
filled as GI but cured with LED while Group IV, each cavity of GIVE and GIVD
filled as GII and cured as GIII. After restorations, the teeth were thermocycled 300
times, soaked in 0.1% methylene blue for 24 hours, sectioned and microleakage from
the gingival margin scored. Statistical analysis was performed using t-test.
There was no significant difference when use sandwich technique in enamel but
There was significant difference in dentin (p≤0.05), while no significant difference
when the comparison between enamel and dentin, whether LED or H curing was used.
With sandwich technique, the marginal adaptation of enamel margins was not
dependent on the restorative technique while marginal adaptation in dentin was
significantly better. The use of LED had no adverse effect on microleakage.