Investigation of the effects of fluoride varnish, silver diamine fluoride and peptide P11-4 on dentin nanostructure in an in-vitro dentin caries model via SEM, FTIR spectroscopy and SAXS methods

Background: To evaluate and compare the structural effects of fluoride varnish, silver diamine fluoride (SDF), and peptide P11-4 on dentin nanostructure in an in vitro dentin caries model. Methods: Forty dentin discs were demineralized and treated with either SDF, fluoride varnish or P11-4. Structural changes were assessed using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and small-angle X-ray scattering (SAXS) to evaluate topographical, molecular and nanoscale modifications. Results: SEM revealed morphological differences across groups: the P11-4 group showed fibrillar structures and narrowed dentinal tubules; the SDF group exhibited blocked tubules with a granular appearance; and the fluoride varnish group presented partially occluded tubules. FTIR analysis showed a reduction in Amide A and Amide I bands in the P11-4 group, suggesting enhanced interaction with dentin collagen and early-stage remineralization. In contrast, the SDF group showed higher Amide A values, indicating limited interaction with the organic matrix. These spectral shifts imply differential impacts on the preservation and reorganization of the dentin matrix. SAXS analysis confirmed that the P11-4 group exhibited the closest nanostructural resemblance to healthy dentin, whereas the SDF group showed the least similarity. Both the P11-4 and fluoride varnish groups demonstrated organized fibrillar alignment and improved mineral patterning. Conclusions: The findings suggest that P11-4, through its biomimetic action, facilitates favorable nanostructural and molecular changes in demineralized dentin. These effects may contribute to enhanced mechanical stability and long-term clinical outcomes. Broader in vivo studies are warranted to validate these results before clinical application.

Biomimetics; Caries; Dentin; Self-assembling peptide; Preventive dentistry

[1] Morawska-Wilk A, Kensy J, Kiryk S, Kotela A, Kiryk J, Michalak M, et al. Evaluation of factors influencing fluoride release from dental nanocomposite materials: a systematic review. Nanomaterials. 2025; 15: 651.

[2] Tsang PW, Qi F, Huwig AK, Anderson MH, Wesley D, Shi W. A medical approach to the diagnosis and treatment of dental caries. American Health Information Management Association. 2006; 47: 38–42.

[3] Parnell C, Gugnani N, Sherriff A, James P, Beirne PV. Non-fluoride topical remineralising agents containing calcium and/or phosphate for controlling dental caries. Cochrane Database of Systematic Reviews. 2012; 3: 1–10.

[4] American Academy of Pediatric Dentistry. Fluoride therapy. 2023. Available at: https://www.aapd.org/media/Policies_Guidelines/BP_FluorideTherapy.pdf (Accessed: 22 May 2025).

[5] Phyo WM, Saket D, da Fonseca MA, Auychai P, Sriarj W. In vitro remineralization of adjacent interproximal enamel carious lesions in primary molars using a bioactive bulk-fill composite. BMC Oral Health. 2024; 24: 37.

[6] Xu GY, Zhao IS, Lung CY, Yin IX, Lo EC, Chu CH. Silver compounds for caries management. International Dental Journal. 2024; 74: 179–186.

[7] Knight G, McIntyre J, Craig G, Mulyani, Zilm P, Gully N. An in vitro model to measure the effect of a silver fluoride and potassium iodide treatment on the permeability of demineralized dentine to Streptococcus mutans. Australian Dental Journal. 2005; 50: 242–245.

[8] Mungur A, Chen H, Shahid S, Baysan A. A systematic review on the effect of silver diamine fluoride for management of dental caries in permanent teeth. Clinical and Experimental Dental Research. 2023; 9: 375–387.

[9] Zheng FM, Yan IG, Duangthip D, Gao SS, Lo ECM, Chu CH. Silver diamine fluoride therapy for dental care. Japanese Dental Science Review. 2022; 58: 249–257.

[10] American Academy of Pediatric Dentistry. Policy on the use of silver diamine fluoride for pediatric dental patients. 2023. Available at: https://www.aapd.org/media/Policies_Guidelines/P_SilverDiamine.pdf (Accessed: 22 May 2025).

[11] Brunton PA, Davies RP, Burke JL, Smith A, Aggeli A, Brookes SJ, et al. Treatment of early caries lesions using biomimetic self-assembling peptides—a clinical safety trial. British Dental Journal. 2013; 215: E6.

[12] Li Z, Li Y, Yin C. Manipulating molecular self-assembly process at the solid–liquid interface probed by scanning tunneling microscopy. Polymers. 2023; 15: 4176.

[13] Kyle S, Aggeli A, Ingham E, McPherson MJ. Recombinant self-assembling peptides as biomaterials for tissue engineering. Biomaterials. 2010; 31: 9395–9405.

[14] Hardan L, Chedid JCA, Bourgi R, Cuevas-Suárez CE, Lukomska-Szymanska M, Tosco V, et al. Peptides in dentistry: a scoping review. Bioengineering. 2023; 10: 214.

[15] Schmidlin P, Zobrist K, Attin T, Wegehaupt F. In vitro re-hardening of artificial enamel caries lesions using enamel matrix proteins or self-assembling peptides. Journal of Applied Oral Science. 2016; 24: 31–36.

[16] Dawasaz AA, Togoo RA, Mahmood Z, Azlina A, Thirumulu Ponnuraj K. Effectiveness of self-assembling peptide (P11-4) in dental hard tissue conditions: a comprehensive review. Polymers. 2022; 14: 792.

[17] Alkilzy M, Santamaria RM, Schmoeckel J, Splieth CH. Treatment of carious lesions using self-assembling peptides. Advances in Dental Research. 2018; 29: 42–47.

[18] Özkaya ZAG, Hidayet Z. Biomimetic remineralization of dentin. Atatürk University Journal of Faculty of Dentistry. 2020; 30: 156–166. (In Turkish)

[19] Fortunato A, Andreassi S, Franchini C, Sciabica GM, Morelli M, Chirumbolo A, et al. Unlocking success in counseling: how personality traits moderates its effectiveness. European Journal of Investigation in Health Psychology and Education. 2024; 14: 2642–2656.

[20] Dawasaz AA, Togoo RA, Mahmood Z, Ahmad A, Thirumulu Ponnuraj K. Remineralization of dentinal lesions using biomimetic agents: a systematic review and meta-analysis. Biomimetics. 2023; 8: 159.

[21] Fu Y, Ekambaram M, Li KC, Zhang Y, Cooper PR, Mei ML. In vitro models used in cariology mineralisation research—a review of the literature. Dentistry Journal. 2024; 12: 323.

[22] Lopes CDCA, Limirio PHJO, Novais VR, Dechichi P. Fourier transform infrared spectroscopy (FTIR) application chemical characterization of enamel, dentin and bone. Applied Spectroscopy Reviews. 2018; 53: 747–769.

[23] Kline SR. Reduction and analysis of SANS and USANS data using IGOR Pro. Journal of Applied Crystallography. 2006; 39: 895–900.

[24] Tiznado-Orozco GE, García-García R, Reyes-Gasga J. Structural and thermal behaviour of carious and sound powders of human tooth enamel and dentine. Journal of Physics D: Applied Physics. 2009; 42: 235408.

[25] Hill R, Chen X, Lysek DA, Gillam D. An in vitro comparison of a novel self-assembling peptide matrix gel and selected desensitizing toothpastes in reducing fluid flow by dentine tubular occlusion. Journal of Dental and Maxillofacial Research. 2020; 3: 1–11.

[26] Costa R, Reis-Pardal J, Arantes-Oliveira S, Ferreira JC, Azevedo LF, Melo P. Biomimetic remineralization strategies for dentin bond stability—systematic review and network meta-analysis. International Journal of Molecular Sciences. 2025; 26: 3488.

[27] Schlee M, Schad T, Koch JH, Cattin PC, Rathe F. Clinical performance of self‐assembling peptide P11-4 in the treatment of initial proximal carious lesions: a practice-based case series. Journal of Investigative and Clinical Dentistry. 2018; 9: e12286.