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Background <p>Self-adhesive flowable resin composites (SAFRCs) offer simplified, single-step placement and are intended to reduce technique sensitivity, but their bonding remains largely inconsistent. Therefore, this study investigated whether pre-cure contact time and dentin surface finish affect immediate bond strength and interfacial morphology of two commercial SAFRCs.</p> Materials and methods <p>Sound human molars were allocated to 12 groups: two SAFRCs (Vertise™ Flow; Constic) × two finishes (fine vs. coarse diamond) × three pre-cure contact times (immediate/0 min, 1&#xa0;min, 5&#xa0;min). For positive controls a universal adhesive/conventional composite were applied. Three 2 × 2-mm cylinders/group were bonded to mid-coronal dentin discs and were light-cured (20&#xa0;s; 950 mW/cm²) and tested in shear bond strength setup (SBS; 24&#xa0;h at 1&#xa0;mm/min). One fractured disc/group was examined by SEM and ~ 1-mm interface slices underwent Masson’s trichrome and were imaged at 100× with calibrated scaling. The 12 SAFRC groups were analyzed by three-way ANOVA with Tukey’s (α = 0.05); comparisons with the matched controls were performed separately using one-way ANOVA followed by Dunnett’s test.</p> Results <p>Material (<i>p</i> = 0.02) and application time (<i>p</i> &lt; 0.0001) significantly affected SBS; surface finish did not (<i>p</i> = 0.97). Five-minute pre-cure contact yielded the highest SBS for both SAFRCs and, in several groups, values not significantly different from the matched controls. SEM showed an application time-dependent improvement of the interface quality: with 0&#xa0;min application showing no continuous interfacial resin/tubule tags; from 1 to 5&#xa0;min, progressively continuous resin fronts with tags, most evident at 5&#xa0;min, irrespective of finish. Masson’s trichrome revealed a more conspicuous dark-pink collagen band at the interface of immediate cure samples and attenuated/discontinuous after 1–5&#xa0;min. Surface finish mainly altered interfacial contour without qualitative improvement.</p> Conclusion <p>Prolonged pre-cure contact enhances SAFRC bonding; the tested roughness range was not determinative. Trichrome staining corroborates shallow demineralization with partially exposed collagen, indicating limited monomer infiltration and explaining the material-dependent, low bond efficacy of current SAFRCs.</p>

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Pre-cure contact time and dentin surface roughness in modulating bonding and impregnation of self-adhesive composites to dentin

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年4月2日

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  • Inês Miranda,
  • Teresa Andrade e Sousa,
  • Pedro Pereira,
  • António HS Delgado

摘要

Background

Self-adhesive flowable resin composites (SAFRCs) offer simplified, single-step placement and are intended to reduce technique sensitivity, but their bonding remains largely inconsistent. Therefore, this study investigated whether pre-cure contact time and dentin surface finish affect immediate bond strength and interfacial morphology of two commercial SAFRCs.

Materials and methods

Sound human molars were allocated to 12 groups: two SAFRCs (Vertise™ Flow; Constic) × two finishes (fine vs. coarse diamond) × three pre-cure contact times (immediate/0 min, 1 min, 5 min). For positive controls a universal adhesive/conventional composite were applied. Three 2 × 2-mm cylinders/group were bonded to mid-coronal dentin discs and were light-cured (20 s; 950 mW/cm²) and tested in shear bond strength setup (SBS; 24 h at 1 mm/min). One fractured disc/group was examined by SEM and ~ 1-mm interface slices underwent Masson’s trichrome and were imaged at 100× with calibrated scaling. The 12 SAFRC groups were analyzed by three-way ANOVA with Tukey’s (α = 0.05); comparisons with the matched controls were performed separately using one-way ANOVA followed by Dunnett’s test.

Results

Material (p = 0.02) and application time (p < 0.0001) significantly affected SBS; surface finish did not (p = 0.97). Five-minute pre-cure contact yielded the highest SBS for both SAFRCs and, in several groups, values not significantly different from the matched controls. SEM showed an application time-dependent improvement of the interface quality: with 0 min application showing no continuous interfacial resin/tubule tags; from 1 to 5 min, progressively continuous resin fronts with tags, most evident at 5 min, irrespective of finish. Masson’s trichrome revealed a more conspicuous dark-pink collagen band at the interface of immediate cure samples and attenuated/discontinuous after 1–5 min. Surface finish mainly altered interfacial contour without qualitative improvement.

Conclusion

Prolonged pre-cure contact enhances SAFRC bonding; the tested roughness range was not determinative. Trichrome staining corroborates shallow demineralization with partially exposed collagen, indicating limited monomer infiltration and explaining the material-dependent, low bond efficacy of current SAFRCs.