Effect of incorporation of calcium polyphosphate sub-microparticles in low-concentration bleaching gels on physical properties of dental enamel

Odontology. 2024 Jul;112(3):729-738. doi: 10.1007/s10266-023-00875-0. Epub 2023 Dec 26.

Abstract

Aim: To evaluate the bleaching efficacy and effects on enamel properties of experimental gels with carbamide peroxide (CP; 10%) or hydrogen peroxide (HP; 6%) containing calcium polyphosphate sub-microparticles (CaPPs).

Methods: A total of 216 bovine tooth specimens were divided for microhardness and color analyses (n = 108) and block randomized into nine groups (n = 12): (G1) commercial CP (Whiteness Perfect, FGM; Brazil); (G2) experimental CP; (G3) CP-0.5%CaPPs; (G4) CP-1.5%CaPPs; (G5) commercial HP (Potenza Bianco, PHS; Brazil); (G6) experimental HP; (G7) HP-0.5%CaPPs; (G8) HP-1.5%CaPPs; (G9) artificial saliva. The gels' pH values were determined with a bench pH meter. Color (ΔE, ΔE00, ΔWID) and microhardness variation were evaluated before and after the therapy. Part of the specimens used for microhardness was submitted to the scanning electron microscopy (SEM) (n = 3) and energy-dispersive X-ray spectroscopy EDX (n = 3) analyses. Statistical analyses were performed in the R statistical software (α = 0.05). Linear mixed models for repeated measures in time were used to analyze microhardness and L* values. Generalized linear models were used to analyze the a*, b*, ΔE, ΔE00, and ΔWID, considering a group effect. The EDX data were analyzed using a one-way ANOVA with Tukey's test.

Results: The gels' pH remained over 6,0. All gels effectively bleached the specimens and did not differ significantly. When compared to the control group, the hardness was significantly lower in the G1, G2, G6, and G7 groups. The G3, G4, G5, and G8 groups did not differ significantly (p > 0.05).

Conclusion: The incorporation of CaPPs in low-concentration whitening gels reduces its negative effects on microhardness without interfering with their bleaching efficacy.

Keywords: Calcium; Dental bleaching; Dental enamel; Peroxides; Polyphosphates.

MeSH terms

  • Animals
  • Carbamide Peroxide* / pharmacology
  • Cattle
  • Color
  • Dental Enamel* / drug effects
  • Gels*
  • Hardness
  • Hydrogen Peroxide* / chemistry
  • Hydrogen-Ion Concentration
  • In Vitro Techniques
  • Microscopy, Electron, Scanning*
  • Particle Size
  • Peroxides / pharmacology
  • Polyphosphates* / chemistry
  • Polyphosphates* / pharmacology
  • Spectrometry, X-Ray Emission
  • Surface Properties
  • Tooth Bleaching Agents* / chemistry
  • Tooth Bleaching Agents* / pharmacology
  • Tooth Bleaching* / methods
  • Urea / analogs & derivatives
  • Urea / chemistry
  • Urea / pharmacology

Substances

  • Gels
  • Hydrogen Peroxide
  • Tooth Bleaching Agents
  • Polyphosphates
  • Carbamide Peroxide
  • Peroxides
  • Urea

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