Resin composite shrinkage and marginal adaptation with different pulse‐delay light curing protocols

Abstract

The aims of this study were, first, to measure shrinkage induced by different methods of pulse‐delay light curing and, second, to verify their influence on the marginal adaptation of class V restorations in enamel and dentin. Eight groups, comprising seven groups (n = 6) with different pulse‐delay parameters and a control group, were compared for dynamic linear displacement and force by using a fine hybrid composite. Based on these results, the pulse‐delay curing procedure with the lowest shrinkage force was chosen and tested against the control group with respect to marginal adaptation in class V restorations (n = 8) before and after simultaneous thermal and mechanical loading. Statistically significant differences between groups were found for both shrinkage properties tested, with one pulse‐delay group giving the lowest overall shrinkage values. However, the percentages of ‘continuous margin’ of this group, and of the control before and after loading, were not significantly different in dentin, whereas a significantly lower percentage of ‘continuous margin’ was detected in the pulse‐delay group in enamel after loading.

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

“…However, a certain number of researchers determined the differences in the quality of marginal adaptation of composites by means of successive or SOF polymerization technique (23)(24)(25)(26)(27), which is in accordance with the results of our study. The results of other researchers may be connected with the application of other methodologies of examining marginal closing, other composite systems and different light sources.…”

Polymerization shrinkage stresses in different restorative techniques for non-carious cervical lesions

“…Polymerization shrinkage produces stress at the tooth/restoration interface, which may result in the formation of marginal gaps, microleakage and micro-cracking that promote degradation and marginal staining [7,9,10]. This, in turn, may contribute to the development of postoperative sensitivity, secondary caries [11,12] and pulpal inflammation resulting from the penetration of saliva, bacteria, and other irritating substances through the debonded interface [12].…”

Monomer conversion and shrinkage force kinetics of low-viscosity bulk-fill resin composites

“…However, polymerization shrinkage is highly correlated to polymerization stress, which is known as a contributing factor for restoration failure [9]. This polymerization-induced stress, being the result of confining the shrinking material by bonding to cavity walls, is considered responsible for a series of clinical complications including tooth-composite interfacial debonding [10], enamel cracking [11], cuspal deflection [12], post-operative sensitivity [13], and secondary caries [14]. Besides volumetric shrinkage and imposed cavity restrictions, the visco-elastic behavior of the material, usually described in terms of elastic modulus development and flow capacity, is an important determinant in the development of polymerization stress [15].…”