Effect of Three Different Pastes on Remineralization of Initial Enamel Lesion: An in Vitro Study

Effect of Three Different Pastes on Remineralization of Initial Enamel Lesion: An in Vitro Study

Effect of Three Different Pastes on Remineralization of Initial Enamel Lesion: An in Vitro Study

Published In: Journal of Clinical Pediatric Dentistry
Publication Year: 2015

Study Design

This was an in vitro comparative laboratory study using a pH-cycling model. Extracted human enamel blocks with artificially induced early lesions were treated with different pastes, then evaluated using Vickers surface microhardness (SMH) and scanning electron microscopy (SEM).

Funding Sources

No funding or grant support was reported in the article or in the PubMed record.

PICO Framework – what was studied and how?

Population
Enamel blocks prepared from freshly extracted sound permanent human maxillary incisors with artificially induced initial enamel lesions.

Intervention
Daily application (3 minutes) of 10% nano-hydroxyapatite paste during a 12-day pH-cycling protocol.

Comparison

  • 1000 ppm sodium fluoride paste

  • 10% CPP-ACP paste

  • Deionized water (control)

Outcomes

  • Primary: % Surface Microhardness Recovery (%SMHR) measured at days 3, 6, 9, and 12.

  • Secondary: Enamel surface morphology observed via SEM.

In Paragraph Form
This study evaluated enamel blocks with early caries lesions to test whether 10% nano-hydroxyapatite paste could remineralize enamel compared with 1000 ppm fluoride, 10% CPP-ACP, or a water control. The outcomes were changes in surface hardness (%SMHR) and enamel surface morphology.

Inclusion and Exclusion Criteria

Inclusion: Extracted permanent maxillary incisors with sound enamel suitable for sectioning.
Exclusion: Teeth with cracks, hypoplasia, or pre-existing white spot lesions.

Demographics and Study Flow (Specimens)

  • Total teeth obtained: 26

  • Microhardness testing: 24 enamel blocks (n = 6 per group) randomly assigned to n-HA, CPP-ACP, fluoride, or water control.

  • SEM imaging: Additional blocks imaged before and after cycling.

Primary Outcome Variables and Results

Day-12 %SMHR (mean ± SD):

  • Nano-hydroxyapatite 10%: 63.62 ± 9.14

  • Fluoride 1000 ppm: 60.89 ± 4.50

  • CPP-ACP 10%: 41.17 ± 6.13

  • Water control: 40.17 ± 10.67

Statistical Findings:

  • Both nano-hydroxyapatite and fluoride groups had significantly greater %SMHR compared to CPP-ACP and control at every time point (p < 0.05).

  • No significant difference was found between nano-hydroxyapatite and fluoride groups (all p > 0.1).

  • SEM showed nano-hydroxyapatite created a crystalline surface layer, while fluoride produced globular precipitates, and CPP-ACP had minimal surface change.

Conclusions

Both 10% nano-hydroxyapatite and 1000 ppm fluoride significantly remineralized early enamel lesions. Their effects were statistically similar, while CPP-ACP and water showed little to no improvement in surface hardness.

Discussion: Strengths and Limitations

Strengths

  • Standardized pH-cycling protocol with multiple time points.

  • Combination of quantitative (%SMHR) and qualitative (SEM) outcomes.

Limitations

  • In vitro setting cannot fully replicate saliva, diet, or biofilm in real mouths.

  • Small sample size (n = 6 per group) limits power.

  • Results limited to surface effects; subsurface remineralization (where CPP-ACP might act) was not measured.

Citation

Vyavhare S, Sharma DS, Kulkarni VK. Effect of Three Different Pastes on Remineralization of Initial Enamel Lesion: An in Vitro Study. J Clin Pediatr Dent. 2015;39(2):149-160. PubMed: https://pubmed.ncbi.nlm.nih.gov/

Visual Aids

Quick Table (Day 12 %SMHR)

Group Mean ± SD Significant vs n-HA?
Nano-hydroxyapatite 10% 63.62 ± 9.14 —
Fluoride 1000 ppm 60.89 ± 4.50 No
CPP-ACP 10% 41.17 ± 6.13 Yes (p = 0.004)
Water (Control) 40.17 ± 10.67 Yes (p = 0.016)
Back to blog