Nutrient-Doped Hydroxyapatite: Structure, Synthesis and Properties

A review on innovations in hydroxyapatite: advancing sustainable and multifunctional dental implants

The increasing relevance of biomaterials in medical curements and the care of aging populations has led to significant advancements in the development and modification of these materials. Hydroxyapatite (HAp), a biocompatible ceramic that mimics the composition of bone mineral, stands out for its remarkable abilities. Its stability in body fluids and ability to integrate with bone without causing toxicity or inflammation made it a prime candidate for biomedical utilization, particularly in odontology and orthopedics. Dental implants, which necessitate a strong interface with the jawbone to effectively support prosthetic devices, are enhanced by coatings of calcium phosphate-based materials like HAp. This enhances osseointegration, ensuring a strong bond and longevity of the implant. HAp may be synthesized both synthetically and from natural sources like mammalian bones, marine shells, and plants, each offering unique trace elements that improve its bioactivity. The synthesis of HAp involves differential technique, including chemical precipitation, and hydrothermal techniques, each impacting the final abilities of the material. The use of natural sources is especially promising, providing a sustainable, cost-effective alternative that retains essential biocompatibility. Hence, this article aims to explore the synthesis, properties, and biomedical applications of hydroxyapatite (HAp), with a special emphasis on its role in improving the performance and durability of dental implants. It also addresses the challenges in manufacturing and biocompatibility, offering insights into future advancements in this field. By addressing current challenges in manufacturing and biocompatibility, HAp paves the way for more effective and long-lasting dental treatments.

Synthesis and characterization of different nano-hydroxyapatites and their impact on dental enamel following topical application for dental bleaching

OBJECTIVE

This study aims to synthesize, characterize, and assess the penetration of hydrogen peroxide (HP), color change (CC), and surface morphology changes after the application of two distinct nano-hydroxyapatite (nano-HAp).

METHODS

Two nano-HAp were previously synthesized by co-precipitation: one with rod-shaped particles (RS) and the other with spherical-shaped particles (SS). The surface charge of the nano-HAp particles was determined at varying pH levels and characterized by X-ray diffraction patterns and Fourier transform infrared spectroscopy. The morphology of the samples was assessed using scanning electron microscopy (SEM). The nano-HAp particles were applied before the dental bleaching procedure. Forty teeth were divided into four groups (n = 10) according to the bleaching treatment: no treatment, bleaching with 35 % HP only, RS application and bleaching with 35 % HP, and SS application and bleaching with 35 % HP. HP concentration (µg mL-1) was measured using UV-Vis, while CC was evaluated with a digital spectrophotometer (ΔEab, ΔE00 and WID). Additionally, four teeth from each group were selected for SEM analysis. Statistical analysis encompassed one-way ANOVA, Tukey's, and Dunnet's tests.

RESULTS

RS and SS were successfully synthesized by coprecipitation, primarily differing in pH during synthesis. Both variations of nano-HAp morphology significantly reduced HP diffusion into the pulp chamber (p < 0.001). Regarding enamel morphology, groups analyzed post dental bleaching exhibited greater HAp deposition on the enamel surface. Notably, this deposition did not impede CC.

SIGNIFICANCE

The utilization of different nano-HAp morphologies prior to dental bleaching appears to be a promising strategy for mitigating adverse effects associated with dental bleaching procedures.

Synthesis of nano-hydroxyapatite using emulsion, pyrolysis, combustion, and sonochemical methods and biogenic sources: a review

Hydroxyapatite (HAp) is comparable to materials in bone because its chemical components are similar to those contained in animal bone, and thus, its bioactive and biocompatible properties are similar. There are applications for HAp and relevant calcium phosphate in the medical and industrial sectors, and due to the rising demand for HAp nanoparticles, considerable work has been performed to develop a variety of synthetic pathways that incorporate scientifically and practically novel aspects. Numerous studies have been conducted to examine how changes in reaction parameters will successfully influence crucial HAp features. HAp can also be synthesized from biogenic sources such as HAp-rich fish scales or animal bones as an alternative to chemical precursors. Various preparation techniques produce crystals with varying sizes, but it has been found that nano-sized HAp exhibits a greater number of bioactive properties as compared to micron-sized HAp. Rather than considering conventional methods, this review focuses on alternative approaches such as emulsion, pyrolysis, combustion, and sonochemical methods along with waste bio-sources (biogenic sources) to obtain HAp. We summarize the currently accessible information pertaining to each synthesis process, while also focusing on their benefits and drawbacks.