Influence of finishing time on marginal sealing ability of new generation composite bonding systems

Abstract

Although variation in finishing techniques has been shown to affect microleakage, little research has been published on the influence of finishing time on the marginal sealing ability of new generation composite bonding systems. The objective of the present study was to evaluate the influence of finishing time on the enamel and dentine marginal sealing ability of four new generation composite systems. Two class V preparations, which were solely in enamel or dentine, were made on the buccal surfaces of 96 freshly extracted molar teeth. The teeth were randomly divided into four groups of 24 and restored with composite resin (Silux Plus) utilizing the following bonding systems: Scotchbond Multi-purpose, Fuji Bond LC, Prime & Bond 2.0 and Bisco One-step. Half of the restorations in each group were finished immediately after light polymerization and stored for 1 week. For the remaining restorations, finishing was delayed for 1 week. The storage medium was isotonic saline at 37 degrees C throughout the experiment. All restorations were then thermocycled, subjected to dye penetration testing, sectioned and scored. The results suggest that the finishing of composite restorations, bonded with the bonding systems evaluated, should be carried out immediately after light polymerization. Delayed finishing does not improve but instead can be detrimental to the marginal seal of the restorations. The effects of delayed finishing are, however, both bonding system and tissue specific.

The Effect of Polishing Techniques and Time on the Surface Characteristics and Sealing Ability of Resin Composite Restorations After One-year Storage

“…15,38 The thermal insults produced by rotational instruments during finishing and polishing procedures can somewhat affect marginal sealing of the restorations. 27,39 The results of the current study show that, after one year, there were no differences among the groups. A reasonable explanation is that the storage period compromised adhesion between the composite and cavity walls, possibly due to adhesive degradation.…”

“…45 In this way, delayed polishing procedures could compromise the marginal sealing obtained with the hygroscopic expansion of the composite and adhesive system, resulting in an increase in microleakage due to the stresses generated by the procedures. 27 Immediate finishing and polishing could also compromise the initial marginal sealing; however, hygroscopic expansion could somehow compensate for the damage caused by immediate polishing. 15,27 In terms of microleakage, the aging process in water has been shown to not have an effect on resin composites, 5,46-47 yet there is a reduction in adhesive resistance after long periods of storage, related to adhesive system hydrolysis.…”

“…27 Immediate finishing and polishing could also compromise the initial marginal sealing; however, hygroscopic expansion could somehow compensate for the damage caused by immediate polishing. 15,27 In terms of microleakage, the aging process in water has been shown to not have an effect on resin composites, 5,46-47 yet there is a reduction in adhesive resistance after long periods of storage, related to adhesive system hydrolysis. 40,42 Morphological studies indicate that the resin and collagen matrix may suffer degradation from storage.…”

“…23 Different methods can be used for restorations' finishing and polishing; 21 however, there is a lack of consensus as to which material and technique provides the smoothest surfaces for composites, 15,[24][25] and little research has been conducted on the influence of delay in polishing on surface roughness, hardness and the marginal sealing of composite restorations. 15,[26][27][28] Still, there are no publications that address the effect of aging processes or long-term storage related to these properties.…”

Effect of Resin Coating as a Means of Preventing Marginal Leakage beneath Full Cast Crowns

“…The amount of leakage was evaluated on a 5-point scale according to the extent of dye penetration2, 23,29,30) .…”