Influence of Fiber Inserts, Type of Composite, and Gingival Margin Location on the Microleakage in Class II Resin Composite Restorations

Abstract

This study evaluated the influence of fiber inserts, type of composites, and location of the gingival seat on microleakage in Class II resin composite restorations. Fifty noncarious human third molars were selected for the study. Standardized Class II box type cavities were prepared on the mesial and distal side of 45 teeth. The gingival margin was placed above the cementoenamel junction (CEJ) on the mesial side and below the CEJ on the distal side. The remaining five teeth received no cavity preparations. The prepared samples were divided randomly on the basis of type of composite and presence or absence of fiber inserts, into four experimental groups of 10 teeth each and two control groups of five teeth each. The groups were defined as follows: group I (n=10) - Z350 XT; group II (n=10) - Z350 XT with fibers; group III (n=10) - P90; group IV (n=10) - P90 with fibers; and group V (n=5) - positive controls, cavities were not restored; group VI (n=5) - negative controls, no cavities were prepared. The samples were stored in distilled water in incubator at 37°C for 24 hours and then subjected to 500 cycles of thermocycling (5°C and 55°C) with a dwell time of 15 seconds. They were then placed in a 2% methylene blue dye solution for 24 hours at 37°C. Samples were sectioned longitudinally and evaluated for microleakage at the occlusal and gingival margin under a stereomicroscope at 20× magnification. Kruskal-Wallis and Mann-Whitney U-tests were used to compare the mean leakage scores. Restorations with gingival margins in enamel showed significantly less microleakage. Significant reduction in microleakage was observed in groups restored with P90 composite than those restored with Z350 XT. No improvement in microleakage was observed with the use of fiber inserts (p>0.05).

Effect of fiber reinforcement on microleakage of class II cavities restored with a novel G‐ænial posterior composite, silorane composite, and nanohybrid composite: an in vitro comparative study

“…Results contradictory those of the present study have also been reported by Dhingra et al . and Belli et al ., in which no reduction in microleakage is shown. One reason for such contrasting results might be the difference in method of placing the restorations, or difference in type of fibers used.…”

“…Light‐cure composites have become the material of choice as a direct posterior restorative material in clinical dentistry . This revolution is due not only because of their excellent esthetic properties, but also to their excellent workability, increased flexural modulus, increased depth of cure, and above all, their adhesion to dental tissues .…”

“…Light‐cure composites have become the material of choice as a direct posterior restorative material in clinical dentistry . This revolution is due not only because of their excellent esthetic properties, but also to their excellent workability, increased flexural modulus, increased depth of cure, and above all, their adhesion to dental tissues . However, this posterior composites undergo polymerization shrinkage of 2.6–7.1%, developing internal and interfacial stresses leading to gap formation and microleakage .…”

Factors affecting marginal integrity of class II bulk-fill composite resin restorations

“…QTH Astralis 7 (Ivoclar, Vivadent, Lichtenstein) and LED Demetron A2 (Kerr, Donbury, Italy) were used for light-curing of composite resins at a light intensity of 1000 mW/cm 2 for 20 and 10 seconds, respectively. Table 1 presents the particulars of the materials used in the present study.…”

“…1 Microleakage leads to recurrent caries, postoperative sensitivity, marginal discoloration and loss of the restoration. 2,3 Therefore, a large number of studies have been undertaken on techniques that result in a decrease in polymerization shrinkage, including placement of composite resins using the incremental technique, use of materials with low elastic modulus to absorb stresses and use of techniques to decrease the C-factor. 4-7 Since these techniques are time-consuming and increase the chair time, resin-based composite (RBC) manufacturers have made significant developments to reduce the shrinkage stress generated on light irradiation and today dentistry boasts of RBC filler technology that encompasses nanotechnology, 8 polymerization modulators technology 9 and non-methacrylate-based monomeric resin formulations.…”