Effect of 5% glycolic acid on immediate and aged bond strength of epoxy resin and bioceramic sealers after calcium hydroxide medication: An in vitro study

Aim: The aim of the study is to evaluate the effect of 5% glycolic acid on immediate and thermocycled push-out bond strength (POBS) of epoxy resin-based and hydraulic calcium silicate-based sealers following calcium hydroxide (Ca(OH) 2 ) medication. Methods: This in vitro factorial study included 200 extracted single-rooted human premolars. Specimens were assigned based on intracanal medication (Ca(OH) 2 or none), final irrigant (5% glycolic acid, 17% ethylenediaminetetraacetic acid [EDTA], or saline), sealer type (AH Plus or Bio-C Sealer), and aging condition (immediate or thermocycled; 10,000 cycles). POBS (MPa) was measured from standardized middle-third root slices and analyzed using four-way ANOVA and Tukey’s post hoc tests ( P = 0.05). Results: Ca(OH) 2 significantly reduced bond strength ( P < 0.001). Irrigant type had a significant effect, with glycolic acid showing higher values than EDTA and saline. In medicated groups, glycolic acid demonstrated greater bond strength than EDTA ( P = 0.004) and saline ( P < 0.001). AH Plus showed higher bond strength than Bio-C sealer ( P = 0.009). Thermocycling significantly reduced bond strength ( P < 0.001), with a significant interaction between sealer type and aging. Conclusion: Ca(OH) 2 and thermocycling adversely affected bond strength. Glycolic acid showed improved performance compared with EDTA and saline, particularly in medicated conditions. However, these findings should be interpreted with caution given the in vitro design.