A fluid filtration and clearing technique to assess microleakage associated with three dentine bonding systems

Objectives The aims of this in vitro study were to (a) measure fluid flow t hrough teeth restored with one of three dentine bonding systems and a resin composite restoration; (b) measure the distribution of a silver tracer thr ough the same teeth, and make a comparison with fluid flow; and (c) investi gate the effect of thermocycling on both measurement types. Methods: Coronal segments of 30 premolars, randomly allocated to three equa l groups, were assessed by fluid filtration. Each group was restored with a resin composite restoration in conjunction with Fuji Bond LC (FBLC), Scotc hbond Multi-Purpose Plus (SMP +) or Prime&Bond 2.1 (P&B2.1). Fluid filtrati on rates were measured in the intact crown and then after cavity preparatio n, conditioning, dentine bonding, restoration and at 2 and 24 h, 1 week and 1 month following restoration. Six specimens from each group were thermocy cled at 1 week. After final filtration measurements the specimens were perf used with silver nitrate and cleared before scoring tracer penetration. Results: No significant differences (P > 0.05) in fluid filtration rates we re found amongst the different bonding systems or at any restoration stage. Thermocycling was not associated with any significant (P > 0.05) increase in fluid filtration. Final fluid filtration and tracer distribution showed a weak and not statistically significant correlation (P > 0.05). The penetr ation of silver stain indicated a failure of the restorations to seal the c avity and demonstrated a possible pathway by which in vivo post-operative s ensitivity could occur. Conclusions: Although not statistically significant, conditioning of the ca vity increased the dentinal permeability but this effect was variable. Ther mocycling had no statistically significant effect on microleakage. (C) 1999 Elsevier Science Ltd. All rights reserved.