Do bleaching gels affect the stability of the masking and caries-arresting effects of caries infiltration-in vitro

Clin Oral Investig. 2021 Jun;25(6):4011-4021. doi: 10.1007/s00784-020-03732-4. Epub 2020 Dec 14.


Objectives: The aim of this study was to evaluate the influence of different bleaching gels on the masking and caries-arresting effects of infiltrated and non-infiltrated stained artificial enamel caries lesions.

Materials and methods: Bovine enamel specimens (n = 240) with each two sound areas (SI and SC) and each two lesions (DI and DC) were infiltrated (DI and SI), stained (1:1 red wine-coffee mixture,70 days), and randomly distributed in six groups to be bleached with the following materials: 6%HP (HP-6), 16%CP (CP-16), 35%HP (HP-35), 40%HP (HP-40), and no bleaching (NBl,NBl-NBr). Subsequently, specimens were pH-cycled (28 days, 6 × 60 min demineralization/day) and all groups except NBl-NBr were brushed with toothpaste slurry (1.100 ppm, 2×/day, 10 s). Differences in colorimetric values (ΔL, ΔE) and integrated mineral loss (ΔΔZ) between baseline, infiltration, staining, bleaching, and pH cycling were calculated using photographic and transversal microradiographic images.

Results: At baseline, significant visible color differences between DI and SC were observed (ΔEbaseline = 12.2; p < 0.001; ANCOVA). After infiltration, these differences decreased significantly (ΔEinfiltration = 3.8; p < 0.001). Staining decreased and bleaching increased ΔL values significantly (p ≤ 0.001). No significant difference in ΔΔE was observed between before staining and after bleaching (ΔEbleaching = 4.3; p = 0.308) and between the bleaching agents (p = 1.000; ANCOVA). pH-cycling did not affect colorimetric values (ΔEpH-cycling = 4.0; p = 1.000). For DI, no significant change in ΔZ during in vitro period was observed (p ≥ 0.063; paired t test).

Conclusions: Under the conditions chosen, the tested materials could satisfactorily bleach infiltrated and non-infiltrated stained enamel. Furthermore, bleaching did not affect the caries-arresting effect of the infiltration.

Clinical relevance: The present study indicates that bleaching is a viable way to satisfactorily recover the appearance of discolored sound enamel and infiltrated lesions.

Keywords: Aesthetics; Bleaching; Caries infiltration; Demineralization; Enamel; In vitro; Staining; White spot lesions.

MeSH terms

  • Animals
  • Cattle
  • Dental Caries Susceptibility
  • Dental Caries*
  • Dental Enamel
  • Gels
  • Hydrogen Peroxide
  • Microradiography
  • Tooth Bleaching Agents*
  • Tooth Bleaching*


  • Gels
  • Tooth Bleaching Agents
  • Hydrogen Peroxide