Long-term ion release, fluoride recharge, pH modulation, and mechanical aging of an experimental ACP-based composite compared with contemporary bioactive restorative materials

Anshuman Shetty; Mohammed Abdul Saleem; Ameer Akhil Ahmed Shaik; Mohammed Mustafa; Rahul Tiwari; Tanisha Shetty

doi:10.1016/j.jobcr.2026.101431

Long-term ion release, fluoride recharge, pH modulation, and mechanical aging of an experimental ACP-based composite compared with contemporary bioactive restorative materials

J Oral Biol Craniofac Res. 2026 May-Jun;16(3):101431. doi: 10.1016/j.jobcr.2026.101431. Epub 2026 Mar 12.

Authors

Anshuman Shetty¹, Mohammed Abdul Saleem², Ameer Akhil Ahmed Shaik³, Mohammed Mustafa⁴, Rahul Tiwari⁵, Tanisha Shetty¹

Affiliations

¹ Department of Conservative Dentistry and Endodontics, NITTE (Deemed to be University) AB Shetty Memorial Institute of Dental Sciences Deralakatte, Mangaluru, Karnataka, 575018, India.
² Department of Oral and Maxillofacial Surgery, Naseem Jeddah Medical Center, Al Oudabaa, Aziziyah, Jeddah, 23342, Saudi Arabia.
³ Narayana Dental College & Hospital, Nellore, Andhra Pradesh, 524003, India.
⁴ Department of Conservative Dental Sciences, College of Dentistry, Prince Sattam Bin Abdulaziz University, Al-Kharj, 11942, Saudi Arabia.
⁵ Department of Dental Research Cell, Dr. D. Y. Patil Dental College and Hospital, Dr. D. Y. Patil Vidyapeeth (Deemed to be University). Pimpri, Pune, 411018, India.

Abstract

Aim: This study evaluated the 12-month ion release, fluoride recharge capacity, pH modulation, mechanical aging, and structural reliability of an experimental amorphous calcium phosphate (ACP)-based composite compared to contemporary bioactive restorative materials.

Methods: An experimental ACP composite was compared with Activa™ BioACTIVE-Restorative, Cention N, and Surefil one ™. Calcium (Ca²⁺), phosphate (PO₄ ^3-), and fluoride (F^-) release, along with pH changes, were assessed over 365 days in artificial saliva. Fluoride recharge was performed at six months using a single application of 5000 ppm sodium fluoride gel, followed by cumulative fluoride re-release measurement for 30 days. The flexural strength and modulus were evaluated at baseline, 6 months, and 12 months. Statistical analysis was conducted using mixed-model ANOVA with post-hoc tests, and flexural strength reliability was assessed using Weibull analysis (α = 0.05).

Results: All materials exhibited an initial burst of ion release, followed by a progressive decline (p = 0.001). The ACP composite demonstrated the highest early calcium and phosphate release but negligible fluoride release and significant reductions in mechanical properties and reliability after aging. Cention N showed sustained multi-ion release, the greatest alkalizing capacity, and stable mechanical performance. Surefil one™ achieved the highest fluoride release and recharge capacity while maintaining a near-neutral pH and superior mechanical reliability. The Activa™ BioACTIVE-Restorative exhibited moderate ion release and intermediate mechanical performance.

Conclusions: Bioactive restorative materials exhibit distinct material-dependent behaviors. Alkasite-based systems showed balanced ion release and mechanical stability, fluoride-focused systems demonstrated superior recharge and reliability, and the ACP composite provided primarily short-term calcium-phosphate release with limited long-term durability.

Keywords: Bioactivity; Calcium phosphate nanoparticles; Dental composites; Fluoride recharge; Mechanical properties.