Reinforcement of glass ionomer cement using ultralong hydroxyapatite nanowires.

Objectives

This study aimed to develop ultralong hydroxyapatite nanowire (UHANW)- reinforced glass ionomer cements (GICs) to improve their mechanical performance for clinical application.

Methods

UHANWs were synthesized via a solvothermal method and incorporated into conventional GICs at 4 wt%, 6 wt%, and 8 wt%. Structure and dispersion were characterized using X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, and transmission electron microscopy. Thermal stability was evaluated by using thermogravimetric analysis-differential scanning calorimetry. The setting time was monitored using FTIR spectroscopy. Flexural compressive, and diametral tensile strengths of the developed GICs were analyzed. Abrasion analysis of the GICs incorporated UHANWs was evaluated with weight loss (%) and surface roughness (Sa, Sq, Sz).

Results

UHANWs exhibited a high aspect ratio (around 10,000) and were uniformly dispersed within the GIC matrix. UHANWs incorporation improved thermal stability and significantly accelerated the acid-base setting reaction of the GICs. Flexural and diametral tensile strengths increased with UHANWs incorporation, with the highest value observed at 6 wt%. In contrast, compressive strength decreased at higher UHANW contents. Abrasion testing showed that 4 -6 wt% UHANW-modified GICs exhibited no significant differences in weight loss and surface roughness compared with control GICs.

Significance

UHANWs provide a biomimetic reinforcement strategy for GICs by leveraging the composition and high-aspect-ratio architecture of hydroxyapatite, a major inorganic component of natural tooth tissues. An optimal UHANW content (6 wt%) achieves a favorable balance between mechanical reinforcement, setting kinetics, and abrasion resistance, supporting its potential application in stress-bearing restorative dentistry.