Toothpaste Composition Effect on Enamel Chromatic and Morphological Characteristics: In Vitro Analysis

Published In: Materials
Publication Year: 2019

Study Design

In vitro experimental study using extracted human teeth to evaluate the effects of various toothpaste formulations on enamel appearance and structure—before and after demineralization.

Funding Sources

This study received no external funding.

PICO Framework – What Was Studied and How?

Population:
Extracted upper premolars from healthy orthodontic patients aged 14–16.

Intervention:
Brushing with one of five different toothpaste formulations—four commercial and one experimental—containing fluoride, nano-hydroxyapatite, or both.

Comparison:
Teeth evaluated at three stages:

1. After initial brushing (T1)

2. After demineralization (T2)

3. After post-demineralization brushing (T3)
   Results were compared across toothpaste groups and stages.

Outcomes:

• Enamel color changes (∆L*, ∆b*, ∆E*) measured via spectrophotometry.

• Surface morphology changes measured via Scanning Electron Microscopy (SEM).

In Paragraph Form:
This in vitro study evaluated how five different toothpaste formulations impacted the color and surface structure of enamel from extracted premolars in adolescents. Researchers compared sound enamel, demineralized enamel, and enamel post-brushing using colorimetric and SEM analysis to determine both cosmetic and structural changes due to toothpaste ingredients.

Inclusion and Exclusion Criteria

Inclusion Criteria:

• Healthy orthodontic patients (age 14–16)

• Presence of 2+ upper premolars requiring extraction

• Teeth free from caries, stains, cracks, or fillings

• Teeth from normodivergent skeletal pattern patients

Exclusion Criteria:

• Teeth not meeting the above health and structural criteria

• Patients without premolars scheduled for extraction

Demographics and Sample Size

• Total teeth used: 25 upper premolars

• Patient count: 15 adolescents (ages 14–16)

• Groups: 5 toothpastes tested (n=5 teeth per group):

  • Lacalut Extra Sensitive

  • Lacalut White & Repair

  • Biomed Sensitive

  • Aslamed for Sensitive Teeth

  • Experimental (Hydroxyapatite + Clay + Potassium Nitrate)

Primary Outcome Variables and Results

Outcome 1: Luminosity (∆L)*

• Increased after initial brushing (T1) for all toothpastes

• Notable ∆L* changes for Lacalut ES, Aslamed ST, and the Experimental formula

• Statistically significant differences in L* across toothpastes (p < 0.05)

Outcome 2: Yellow-Blue Axis (b)*

• Significant changes observed between products

• Notable reduction in yellow tones after demineralization (p < 0.05)

• Biomed showed significant change from T2-T1 and T3-T1

Outcome 3: Overall Color Change (∆E)*

• ∆E* > 3 for all toothpastes after demineralization, indicating visible changes to human eye

• Post-brushing reduced ∆E* but remained perceptible

• Lacalut White & Repair showed the most significant changes

Summary Chart of Primary Outcomes

Conclusions

• Visible changes in enamel color occurred after brushing and demineralization.

• ∆E values > 3.3*, indicating differences detectable by the human eye.

• Nano-hydroxyapatite and fluoride contributed to remineralization.

• SEM confirmed mineral gain in enamel structure post-treatment.

Discussion: Strengths and Limitations

Strengths:

• Controlled in vitro design with consistent brushing protocol

• Use of both colorimetric (CIELAB) and SEM imaging for comprehensive evaluation

• Compared multiple commercially relevant and experimental products

Limitations:

• In vitro nature limits translation to long-term in vivo conditions

• Small sample size (25 teeth total)

• Short treatment window (21-day cycles)

Citation

Muntean A, et al. Toothpaste Composition Effect on Enamel Chromatic and Morphological Characteristics: In Vitro Analysis. Materials. 2019;12(16):2610. https://pubmed.ncbi.nlm.nih.gov/