Scientific Article Review:

Effect of Nano-Hydroxyapatite Toothpaste on Microhardness of Artificial Carious Lesions Created on Extracted Teeth

Published In: Journal of Dental Research, Dental Clinics, Dental Prospects

Publication Year: 2017

Study Design

This study is an in vitro experimental study evaluating the impact of nano-hydroxyapatite (NHA) toothpaste on the microhardness of artificially induced carious lesions.

Funding Sources

The research was supported by Goltash Co. and the Dentofacial Deformities Research Center at Shahid Beheshti University of Medical Sciences. Both funding bodies did not influence the conduct, analysis, or reporting of the study.

PICO Framework - what was studied and how?

Population:
Extracted human premolars free from caries, cracks, or structural defects.

Intervention:
Application of a toothpaste containing 7% nano-hydroxyapatite (NHA) and fluoride (NaF, 1000 ppm).

Comparison:
Application of a toothpaste containing fluoride (NaF, 1000 ppm) without NHA.

Outcomes:

• Changes in dentin microhardness after 15 days of brushing.
• Measurements performed using the Vickers microhardness tester.

In Paragraph Form:
The study focused on evaluating the microhardness of human premolars treated with toothpaste containing 7% NHA and fluoride compared to toothpaste with fluoride alone. The primary outcome was the change in dentin microhardness after acid exposure and 15 days of brushing.

Inclusion and Exclusion Criteria

Inclusion Criteria:

• Extracted premolars with no visible caries, cracks, or structural defects.

Exclusion Criteria:

• Teeth with pre-existing conditions, including hypocalcification or enamel defects.

Demographics and Study Design

The study utilized 80 extracted premolars.

• Group A: 40 teeth treated with toothpaste containing NHA and fluoride.
• Group B: 40 teeth treated with toothpaste containing fluoride alone.

Primary Outcome Variables and Results

Outcome: Change in dentin microhardness (measured in Vickers Hardness Units).

• Before acid exposure: Group A = 70.3 ± 3.4; Group B = 63.6 ± 3.1.
• After acid exposure: Group A = 32.9 ± 1.0; Group B = 36.2 ± 1.0.
• After 15 days of treatment:
  • Group A (NHA + Fluoride): 46.9 ± 1.3
  • Group B (Fluoride only): 42.4 ± 1.7

Statistical Findings:

• Microhardness decreased significantly after acid exposure in both groups (p < 0.01).
• After treatment, Group A exhibited a significantly greater increase in microhardness compared to Group B (p < 0.01).

Conclusions

The study concluded that toothpaste containing NHA and fluoride significantly improves dentin microhardness compared to fluoride-only toothpaste. The synergistic effects of NHA and fluoride provide enhanced remineralization, highlighting its potential as a superior option for caries prevention.

Discussion

Strengths:

• Use of a standardized microhardness testing method.
• Blinded operator and statistician ensured unbiased results.
• Focus on affordable, locally produced toothpaste formulations.

Limitations:

• In vitro design limits the generalizability to clinical conditions.
• Short treatment duration (15 days) may not fully reflect long-term outcomes.
• Results could vary in different oral environments with saliva and diet influences.

Citation

Ebadifar A, Nomani M, Fatemi SA. Effect of nano-hydroxyapatite toothpaste on microhardness of artificial carious lesions created on extracted teeth. J Dent Res Dent Clin Dent Prospect. 2017;11(1):14-17. https://pubmed.ncbi.nlm.nih.gov/

Visual Aids

Simple Chart: Change in Dentin Microhardness