Abstract :
Introduction: Although the use of resin composites has grown considerably, many drawbacks are
associated with their use in the posterior region, such as polymerization shrinkage, gap formation, occlusal
wear, and color instability. To overcome these clinical challenges, manufacturers developed materials and
techniques for indirect construc- tion of resin composite restorations.
Materials and Methods: Freshly extracted eighty premolar teeth were taken for the study which were
free from caries, hypoplastic defects and cracks on visual examination. All teeth were cleaned to remove
surface debris and calculus by ultrasonic scaler. The teeth were disinfected with 0.1% thymol solution and
randomly divided into eight groups of ten (n=10), each based on the storage time, placement of classII
cavity gingival margin and the type of luting agent used. Teeth were mounted. Standardized class II inlay
box cavities were prepared on each tooth. Out of 80 samples, in 40 samples, the gingival margin was kept
1mm coronal to CEJ i.e supragingival, and for the remaining 40 samples, the gingival margin was kept
1mm apical to CEJ i.e subgingival.
Following that, separating medium was applied, composite (Te – economy plus, Ivoclar Vivadent AG,
Shaan, Liechtenstein) was placed incrementally and cured initially (40 sec) using halogen light curing unit
(spectrum 800, densply sirona) with an intensity 650 mW/cm2. Then, the composite inlays were removed
from the teeth and post cured in polymat light curing unit (DeltaDental).
For group I, III,V,VII, the multilink N was used as luting agent for semi indirect inlays.For group II, IV,
VI, VIII the multilink speed was used as luting agent for semi indirect inlays. The luting cements were
mixed and applied as per the manufacturers instructions. The samples were thermocycled using Willy
tech thermocycler for 500 cycles at 5ºc and 55ºc, with 30 seconds dwell time and 5 seconds transfer. The
sections were mounted on slides and the degree of dye penetration was recorded under stereomicroscope
with X20 magnification. Leakage was evaluated according to scores mentioned below for the degree of dye
penetration.
Results: There was no statistically significant difference of microleakage values between the two luting
cements for a storage period of 24 hours (P=0.067) (Table 1) whereas there was statistically significant
difference between them for a storage period of 2 months (P=0.035) for both supra and sub gingival groups
seen at the cervical margin.
Conclusion: Within the limitations of the present study, it can be concluded that Within 24 hours storage
period there is no much difference in micro leakage between Multilink N (self-etch primer adhesive resin
cement) and Multilink speed (self-adhesive resin cement). The greatest level of cervical microleakage was
observed in Multilink speed (self-adhesive resin cement) than Multilink N (self-etch primer adhesive resin
cement) after 2 months storage period.
Keyword :
Microleakage, Multilink N, Multilink speed, Class ii inlay.