The Effect of Toothpastes Containing Hydroxyapatite, Fluoroapatite, and Zn-Mg-hydroxyapatite Nanocrystals on Dentin Hypersensitivity: A Randomized Clinical Trial

Published In: Journal of International Society of Preventive and Community Dentistry
Publication Year: 2022

Study Design

This was a double-blind, randomized, three-arm parallel-group clinical trial designed to compare the effects of three types of apatite-based toothpaste on dentin hypersensitivity over four weeks.

Funding Sources

The study declared no financial support or sponsorship.

PICO Framework – what was studied and how?

Population:
Adults aged 35–45 years with dentin hypersensitivity (DH) caused by noncarious cervical lesions.

Intervention:
Daily use of toothpaste containing:

• Nano-hydroxyapatite (nHAP)

• Nano-Zn-Mg-hydroxyapatite (nZnMgHAP)

• Nano-fluoroapatite (nFAP)

Comparison:
Effectiveness of nZnMgHAP and nFAP toothpaste compared to nHAP toothpaste in reducing dentin hypersensitivity.

Outcomes:
Change in dentin hypersensitivity as measured by the Schiff sensitivity index after 2 and 4 weeks of use.

In Paragraph Form:

This randomized clinical trial assessed adults aged 35–45 suffering from dentin hypersensitivity due to noncarious cervical lesions. Participants were assigned to one of three toothpaste groups containing nano-hydroxyapatite (nHAP), nano-Zn-Mg-hydroxyapatite (nZnMgHAP), or nano-fluoroapatite (nFAP). The study measured the reduction in sensitivity using Schiff scores after 2 and 4 weeks of twice-daily use.

Inclusion and Exclusion Criteria

Inclusion Criteria:

• Age between 35 and 45

• Clinical diagnosis of DH

• One premolar or first molar with a noncarious cervical lesion 1–1.5 mm deep

• Schiff score ≥2 at baseline

• No restorations on adjacent teeth

Exclusion Criteria:

• Pregnancy or breastfeeding

• Allergies to toothpaste ingredients

• Medical conditions causing DH (e.g., acid reflux)

• Recent periodontal surgery or orthodontic treatment (within 3 months)

• Use of other desensitizing products within 4 weeks

• Extensive restorations or prosthetic use in the test area

Demographics and Study Design

• Total participants: 30

• Groups:

  • nHAP: 10 participants

  • nZnMgHAP: 10 participants

  • nFAP: 10 participants

• Age range: 35–45 years

• Gender: ~60–70% female in each group

• All participants completed the study; no adverse effects were reported.

Primary Outcome Variables and Results

Outcome: Change in dentin sensitivity measured by Schiff scores at baseline, 2 weeks, and 4 weeks.

Key Statistical Findings:

• All groups showed significant reductions in Schiff scores by week 4.

• nZnMgHAP toothpaste led to the greatest reduction in sensitivity, with a large effect size (3.30).

• Between-group differences at 4 weeks were statistically significant (p = 0.00083).

Conclusions

The study concluded that:

• All three nano-apatite toothpaste formulations reduced dentin hypersensitivity.

• The Zn-Mg-doped hydroxyapatite (nZnMgHAP) toothpaste showed superior effectiveness at reducing DH compared to both nHAP and nFAP after 2 and 4 weeks.

• nZnMgHAP may be a promising active ingredient for managing dentin hypersensitivity.

Discussion: Strengths and Limitations

Strengths:

• Randomized, double-blind design

• Included both clinical (Schiff index) and laboratory (SEM imaging) outcome measures

• Clear reduction in sensitivity confirmed by both subjective and objective assessments

Weaknesses:

• Small sample size (10 per group)

• Limited age range (35–45 years)

• Short follow-up duration (4 weeks)

• No long-term data on sustained effectiveness or safety

Additional Notes:
SEM imaging revealed almost complete occlusion of dentinal tubules in the nHAP and nZnMgHAP groups, while nFAP showed partial occlusion only. This supports the clinical effectiveness observed.

Citation

Polyakova M, Sokhova I, Doroshina V, Arakelyan M, Novozhilova N, Babina K. The effect of toothpastes containing hydroxyapatite, fluoroapatite, and Zn-Mg-hydroxyapatite nanocrystals on dentin hypersensitivity: A randomized clinical trial. J Int Soc Prev Community Dent. 2022;12(2):252-259.
🔗 https://pubmed.ncbi.nlm.nih.gov/

Visual Aids

Simple Chart: Reduction in Dentin Hypersensitivity (Schiff Scores)
Lower scores indicate less sensitivity.