Nano-hydroxyapatite for dentine hypersensitivity?


Dentine hypersensitivity is a painful condition that can have a negative effect on patients’ quality of life. It is thought to be caused by hydrodynamic effects on dental pulp following the exposure of dentinal tubules. A wide of desensitising agents have been employed to manage the condition and recent studies have suggested promising outcomes with nano-hydroxyapatite.

The aim of this review is to evaluate the clinical effectiveness of nano-hydroxyapatite (n-HAP)-based desensitising agents


Searches were conducted in the PubMed, Web of Science, Cochrane CENTRAL, Scopus, LILACS,, and OpenGrey databases. Randomised controlled studies (RCTs) comparing n-HAP verses non-HAP treatments for placebo for patients with dentine hypersensitivity were considered.

Two reviewers independently screened and selected studies and assessed risk of bias using the Cochrane tool. Meta-analysis was carried out and the quality of the evidence was evaluated using the GRADE appraoch.


  • 8 RCTs (1 split mouth, 7 parallel) were included
  • 3 trials were considered to have a high risk of bias and 5 a low risk.
  • Follow up ranged for 4 weeks to 3 months.
  • Sensitivity was elicited by evaporative, tactile, thermal or electric stimuli.
  • 6 studies contributed to the meta-analyses.
    • Overall analysis showed a significant desensitising effect for n-HAP.
    • n-HAP showed a better desensitising effect for both evaporative and tactile stimuli but not cold stimuli.
  No. of studies Standardised Mean Difference (95%CI)
Evaporative stimuli 5 -1.09 (-1.24 to  -0.94)
Tactile stimuli 4 -0.93 (-1.42 to  -0.43)
Cold stimuli 2 -0.17 ([-0.81 to  0.48)
Overall analysis 6 -0.93 (-1.19 to  -0.68)


The authors concluded: –

desensitizing agents containing n-HAP are effective for the relief of dentine hypersensitivity in both at-home and in-office treatments when compared with others desensitizing agents or placebo/negative control. However, the evidence generated by this review was based on a small number of studies. In addition, long-term follow-up clinical trials are required in the future before definitive recommendations can be made.


A broad database search was undertaken for this review and only RCTs were considered.  In all 8 RCTs were identified and while the authors consider 7 of the included studies to be at low risk of bias 3 of the included studies were assessed as having a high risk of bias in one of the Cochrane criteria so have been incorrectly rated.  In the table describing the studies it suggests that 4 of the studies involving n-HAP also included other agents that have been shown to reduce hypersensitivity which could have an impact on the findings.

We have looked at a number for reviews looking at treatments for dentine hypersensitivity (Dental Elf – Dentine Hypersensitivity Blogs) and one review (Dental Elf -20th Jul 2018) suggests that most agents tested have been effective at managing dentine hypersensitivity. The findings for this review suggest that n-HAP may also be effective but better reported higher quality RCTs are needed to better  assess the relative effectiveness of the most promising agents for the management of dentine hypersensitivity.


Primary Paper

de Melo Alencar C, de Paula BLF, Guanipa Ortiz MI, Baraúna Magno M, Martins Silva C, Cople Maia L. Clinical efficacy of nano-hydroxyapatite in dentin hypersensitivity: A systematic review and meta-analysis. J Dent. 2019 Jan 3. pii: S0300-5712(18)30548-7. doi: 10.1016/j.jdent.2018.12.014. [Epub ahead of print] Review. PubMed PMID: 30611773

Original review protocol on PROSPERO

Other references

Dental Elf – Dentine Hypersensitivity Blogs

Dental Elf -20th Jul 2018

Dentine hypersensitivity: Effectiveness of desensitising toothpastes



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