Evidence map›Paper›PMID 42518060›Full record

ArticleOdontology2026

Eggshell-derived hydroxyapatite as a bioactive filler for toothpaste: rheology and enamel remineralization performance.

Bel Abbes Bachir Bouiadjra, Sarah Bouameur, Amine Yerou, Omar Khatir, Larbi Hammadi, Abdelouahab Ait Kaci, Mohamed Mokhtar Bouziane, Mohamed B Bachir Bouiadjra, Belaid Mechab, Atef Hamada

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Article in Odontology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

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Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

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0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

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PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

10 authors.

Bel Abbes Bachir BouiadjraMechanical Engineering Department, LMPM, University of Sidi Bel Abbes, BP 89 Cité Ben M'hidi, 22000, Sidi Bel Abbes, Algeria.
Sarah BouameurDepartment of Pharmacy, Faculty of Medicine, University of Oran 1, Oran, Algeria.
Amine YerouMechanical Engineering Department, LMPM, University of Sidi Bel Abbes, BP 89 Cité Ben M'hidi, 22000, Sidi Bel Abbes, Algeria.
Omar KhatirMechanical Engineering Department, LMPM, University of Sidi Bel Abbes, BP 89 Cité Ben M'hidi, 22000, Sidi Bel Abbes, Algeria. khatiromar8@gmail.com.ORCID http://orcid.org/0009-0004-3370-5944
Larbi HammadiLaboratory of Rheology, Transport and Treatment of Complex Fluids (LRTTFC), Faculty of Architecture and Civil Engineering, Department of Hydraulics, University of Science and Technology of Oran (USTO), Oran El M'naour, P.O. Box 1505, 31000, Oran, Algeria.
Abdelouahab Ait KaciLEMM Laboratory, Mouloud Mammeri University, Tizi-Ouzou, Algeria.
Mohamed Mokhtar BouzianeMechanical Engineering Department, LMPM, University of Sidi Bel Abbes, BP 89 Cité Ben M'hidi, 22000, Sidi Bel Abbes, Algeria.
Mohamed B Bachir BouiadjraMechanical Engineering Department, LMPM, University of Sidi Bel Abbes, BP 89 Cité Ben M'hidi, 22000, Sidi Bel Abbes, Algeria.
Belaid MechabMechanical Engineering Department, LMPM, University of Sidi Bel Abbes, BP 89 Cité Ben M'hidi, 22000, Sidi Bel Abbes, Algeria.
Atef HamadaKerttu Saalasti Institute, Future Manufacturing Technologies FMT, University of Oulu, Pajatie 5, 85500, Nivala, Finland.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Sustainable and fluoride-free alternatives for oral care products are increasingly sought. This study aimed to valorize eggshell waste as a calcium source for the synthesis of nanocrystalline hydroxyapatite (HAp) and to evaluate its suitability as a multifunctional filler in toothpaste formulations, focusing on rheological, viscoelastic, and enamel remineralization performance. Hydroxyapatite was synthesized from eggshell-derived calcium oxide via wet chemical precipitation and characterized using particle size analysis, FTIR, and XRD. Toothpaste formulations containing 0, 3, 5, and 7 wt% HAp were prepared. Steady shear and dynamic oscillatory rheological measurements were performed and fitted using the Herschel-Bulkley model. In vitro, remineralization was assessed on artificially demineralized bovine enamel using Vickers microhardness testing before demineralization, after lesion formation, and after treatment with HAp-based toothpaste. The synthesized HAp was phase-pure and nanocrystalline, with an average crystallite size of approximately 12-14 nm. All formulations exhibited non-Newtonian shear-thinning behavior with a well-defined yield stress. Increasing HAp content significantly enhanced yield stress, consistency index, storage modulus, and critical stress, indicating progressive reinforcement of the internal microstructure. The formulation containing 5 wt% HAp showed the most balanced viscoelastic properties. Artificial demineralization reduced enamel microhardness by approximately 53% compared with sound enamel. Treatment with HAp-based toothpaste significantly increased microhardness (p < 0.001), restoring values to levels not statistically different from sound enamel. The calculated remineralization percentage reached 115.97%, suggesting effective mineral deposition and surface reconstruction. Eggshell-derived hydroxyapatite acts as both a rheological reinforcing agent and a biomimetic remineralizing material in toothpaste formulations. An optimal loading of 5 wt% provides improved mechanical integrity and controlled flow behavior while promoting substantial enamel remineralization under vitro conditions. This study supports the use of eggshell-derived hydroxyapatite as a sustainable biomimetic remineralizing agent for fluoride-free or fluoride-complementary toothpaste formulations, combining favorable handling properties with significant enamel remineralization potential.

Indexed as

Eggshell wasteEnamel remineralizationHydroxyapatiteRheologySustainable materialsToothpaste formulationViscoelastic propertiesYield stress

Identifiers

PMID42518060

What OpenQuestion holds

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Read underepoch 390

Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.