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

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.

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).

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).

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.

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.