The Effects of Calcium Hydroxide–loaded Poly (Lactic-co-glycolic Acid) Biodegradable Nanoparticles in the ex vivo External Inflammatory Root Resorption Model

Abstract

Aim: To evaluate the calcium ions (C2+) diffusion of calcium hydroxide-loaded poly(lactic-co-glycolic acid) biodegradable nanoparticles [Ca(OH)2-loaded PLGA NPs] compared with conventional Ca(OH)2 in a simulated external root resorption ex vivo model using inductively coupled plasma mass spectrometry (ICP-MS). Materials and methods: Thirty human mandibular premolars were prepared by sectioning the root segments to create roots measuring 10 mm from the anatomical apex. The root canals were instrumented and irrigated. The external root surface cavities were created. The specimens were randomly divided into the following three groups: Poly(lactic-co-glycolic acid) (PLGA; control group, n = 10), conventional calcium hydroxide [Ca(OH)2] (Metapaste, n = 10), and Ca(OH)2-loaded PLGA NPs [15% Ca(OH)2, n = 10]. The intracanal materials were placed in the root canals, and the teeth were stored in phosphate-buffered saline at 37°C. The release of C2+ was measured at 7, 30, and 60 days using ICP-MS. Results: Both Ca(OH)2-loaded PLGA NPs and Metapaste groups exhibited higher levels of C2+ release compared to the PLGA group at all time points. During the initial 7-day period, the Ca(OH)2-loaded PLGA NPs exhibited a significantly greater release of C2+ compared to Metapaste. From day 7 to day 30, Metapaste displayed a significantly higher release of C2+ than the Ca(OH)2-loaded PLGA NPs, but it experienced a subsequent decline in C2+ release after the 30-day period. After the 30-day mark, the Ca(OH)2-loaded PLGA NPs once again exhibited a significantly higher release of C2+ compared to Metapaste. Conclusion: The Ca(OH)2-loaded PLGA NPs exhibited sustained release of C2+ that exceeded conventional Ca(OH)2, particularly during the first week, demonstrating a greater amount of C2+ release. Clinical significance: The utilization of Ca(OH)2-loaded PLGA NPs as an intracanal medication for external inflammatory root resorption provided sustained release and had the potential to enhance the efficacy of inhibiting root resorption more effectively than conventional Ca(OH)2.