The influence of calcium fluoride nanoparticles’ addition on the bond integrity, degree of conversion, ion-release, and dentin interaction of an adhesive

• Published in: Applied nanoscience Vol. 12; no. 11; pp. 3477 - 3488
• Main Authors: Al-Saleh, Samar, Tulbah, Huda I., Al-Qahtani, Amal S., Binhasan, Mashael, Shabib, Sara, Albaqawi‬, Ahmed Heji, Farooq, Imran, Vohra, Fahim, Abduljabbar, Tariq
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.11.2022; Springer Nature B.V
• Subjects: Adhesive strength; Adhesives; Bond strength; Bonding strength; Calcium fluoride; Chemical bonds; Chemistry and Materials Science; Conversion; Dentin; Failure analysis; Failure investigations; Fillers; Fluorides; Fluorine; Fourier transforms; Infrared spectroscopy; Materials Science; Mechanical properties; Membrane Biology; Nanochemistry; Nanocrystals; Nanoparticles; Nanotechnology; Nanotechnology and Microengineering; Original Article; Raman spectra; Raman spectroscopy; Scanning electron microscopy; Spectrum analysis; Dentin; Spectroscopy; Fluoride; Calcium; Adhesive; Bonding
• ISSN: 2190-5509; 2190-5517
• DOI: 10.1007/s13204-021-02282-9

The study aimed to synthesize, characterize, and assess dentin bonding, ion-release, and degree of conversion (DC) of experimental adhesive (EA) with and without 5 wt% and 10 wt% calcium fluoride (CaF 2 ) nanocrystals. The CaF 2 nanocrystals were synthesized and characterized with scanning electron microscopy (SEM), line-Energy Dispersive X-Ray (EDX) spectroscopy, Fourier-transform infrared (FTIR).and micro-Raman spectroscopy techniques. Adhesives were characterized using micro-tensile bond strength test (μTBS), SEM–EDX spectroscopy, inter-facial failure investigation, adhesive-dentin interface examination, ion release measurements, FTIR, and DC analysis. One hundred five ( n  = 105) teeth were collected, their dentinal tissue was exposed, and the adhesives were applied pre-characterization of the adhesives. On SEM, CaF 2 nanocrystals were seen as irregularly shaped agglomerates. The EDX mapping demonstrated calcium and fluoride’s presence for the CAF-5% and CAF-10% groups. The FTIR and micro-Raman spectra indicated characteristic bands for CaF 2 containing materials. For the NTC samples, the highest μTBS (33.87 ± 3.26 MPa) was observed for CAF-10%. For the TC samples, the highest μTBS (30.48 ± 3.41 MPa) was observed for CAF-10%. Adhesive type failures were most common and the CaF 2 containing adhesives revealed comparable resin tag formation to the controls. The presence of calcium and fluorine on EDX analysis was observed for CaF 2 adhesives. For the CaF 2 adhesives, an increased release of both ions was seen with a lowering pH and a lower DC was observed. Reinforcing of EA with CaF 2 filler improves its mechanical properties. Further studies exploring the effect of diverse filler concentrations on different properties of the adhesive are warranted.