Effect of the Insertion and Polymerization Technique in Composite Resin Restorations: Analysis of Marginal Gap by Atomic Force Microscopy

Abstract

This in vitro study evaluated the marginal gap at the composite tooth/resin interface in class V cavities under the influence of two insertion techniques and a curing system by means of atomic force microscopỹ AFM!. Forty enamel and dentin cavities were prepared on the buccal surface in bovine teeth with quadratic forms measuring 2 mm ϫ 2 mm and depth of 1.5 mm. The teeth were then divided into four groups: group A, 10 cavities were restored in one increment, light cured by halogen light; group B, 10 cavities filled with bulk filling, light cured by the light emitting diodes~LED!; group C, 10 cavities were restored by the incremental technique, light cured by halogen light; group D, 10 cavities were restored by the incremental technique, light cured by the LED. The teeth underwent the polishing procedure and were analyzed by AFM for tooth/ restoration interface evaluation. The data were compared between groups using the nonparametric KruskallWallis and Mann-Whitney tests~p , 0.05!. The results showed a statistically significant difference between groups A and B and groups A and C. It was concluded that no insertion and polymerization technique was able to completely seal the cavity.

The bond strength of highly filled flowable composites placed in two different configuration factors

“…Although incremental placement techniques have the advantage of maximizing polymerization of each increment and increased adaptation of the composite to cavity walls, the effect on shrinkage stress should be questioned. [ 9 ]…”

Direct‐Indirect Class V Restorations: A Novel Approach for Treating Noncarious Cervical Lesions

“…The composite resin quantity, cavity geometry, and C‐factor are reported to influence the shrinkage stress exerted on the tooth in class V restorations . Layering techniques have been advocated to minimize the undesired consequences of composite shrinkage (i.e., post‐operative sensitivity, microleakage), but there are divergent findings regarding the efficacy of incremental layering versus bulk filling . The benefits of bulk filling class V defects, however, make it more attractive to operators, because they frequently include use of a single shade, thus minimizing the number of steps and reducing operative time.…”

“…38,39 Layering techniques have been advocated to minimize the undesired consequences of composite shrinkage (i.e., post-operative sensitivity, microleakage), [40][41][42] but there are divergent findings regarding the efficacy of incremental layering versus bulk filling. [43][44][45] The benefits of bulk filling class V defects, however, make it more attractive to operators, because they frequently include use of a single shade, thus minimizing the number of steps and reducing operative time. Depending on cavity/lesion size and depth, incremental layering or bulk filling may be indicated for both the direct and direct-indirect class V approaches, primarily for esthetic reasons, as composites of varying chroma and opacity may be utilized.…”

The Effect of Polymerization Technique on Marginal Index of Composite Fillings in Dentin

“…It is well known that numerous factors influence the contraction, some of which include: chemical composition, polymerization rate, polymerization system, the elasticity module of restorative materials, cavity configuration factor (factor C) (2). Polymerization depends on the size of inorganic composite particles and their composition, color, transparency, light intensity, duration of illumination exposure, as well as the monomer composition and the polymerization initiator concentration (3).…”