Role of Amine and/or Tin-Containing Dentifrices on Tooth Discoloration and Surface Properties.

Abstract

Objective: This study evaluated the impact of dentifrices containing amine fluoride (AmF) and/or tin on tooth discoloration and surface roughness under cycles of staining and abrasion.

Materials and methods: Specimens of enamel (n = 10) and dentin (n = 19) were allocated into six groups: (1) Negative control (Distilled water), (2) NaF (regular fluoridated dentifrice without amine and tin), (3) AmF, (4) AmF/NaF/SnCl₂, (5) SnF₂/SnCl₂, and (6) SnF₂. Daily staining-toothbrushing cycling was performed: staining solution (30 min), toothbrushing (45 strokes), and human saliva (1 h), 2×/day, for 21 days. Tooth color change (ΔE, ΔL, Δa, and Δb) was determined using a spectrophotometer (CIEDE2000), while surface roughness (ΔRa) was measured with an optical profilometer, and the data were statistically analyzed (α = 0.05).

Results: For enamel, no significant differences in ΔE were observed among groups; however, for dentin, AmF exhibited the highest ΔE value, differing from all groups except Negative control (p > 0.05). Both substrates showed a decrease in luminosity (-ΔL), with significant differences in dentin for the AmF group (p < 0.05). For dentin, all groups showed an increase in tooth yellowness (+Δb); while for enamel, only the tin-containing groups showed this effect. All groups showed an increase in surface roughness after cycling. Enamel Ra showed significant differences post-treatment, with AmF differing from NaF/AmF/SnCl₂ (p = 0.012) and control (p = 0.042). Correlations between ΔRa and ΔE were weak in both substrates (ρ = 0.12 for enamel; ρ = 0.22 for dentin).

Conclusions: Brushing with AmF/NaF/SnCl₂, SnF₂/SnCl₂, and SnF₂-containing toothpastes promoted a yellowing of enamel. Brushing with AmF resulted in the greatest darkening of dentin compared with other fluoride salts.

Clinical significance: Some components in dentifrices can induce tooth discoloration, which seems to impact dental aesthetics; therefore, clinicians should advise patients on potential color alterations when choosing specific dentifrice products.