Hierarchically Designed Biodegradable Polylactide Particles with Unprecedented Piezocatalytic Activity and Biosafety for Tooth Whitening

Abstract

At-home tooth whitening solutions with good efficacy and biosafety are highly desirable to meet the ever-growing demand for aesthetic dentistry. As a promising alternative to the classic peroxide bleaching that may damage tooth enamel and gums, piezocatalysis has been recently proposed to realize nondestructive whitening by toothbrushing with piezoelectrical particles. However, traditional particles either pose potential threats to human health or exhibit low piezoresponse to weak mechanical stimuli in the toothbrushing. Here, biocompatible and biodegradable polylactide particles constructed from interlocking crystalline lamellae have been hierarchically designed as next-generation whitening materials with ultra-high piezocatalytic activity and biosafety. By simultaneously controlling the chain conformation within lamellae and the porosity of such unique lamellae network at the nano-and microscales, the particles possessing unprecedented piezoelectricity have been successfully prepared due to the markedly increased dipole alignment, mechanical deformability, and specific surface area. The piezoelectric output can reach as high as 18.8 V, nearly 50 times higher than that of common solid polylactide particles. Consequently, their piezocatalytic effect can be readily activated by a toothbrush to rapidly clean the teeth stained with black tea and coffee, without causing detectable enamel damage. Furthermore, these particles have no cytotoxicity. This work presents a paradigm for achieving high piezoelectric activity in polylactide, which enables its practical application in tooth whitening.

Self-Charging, Breathable, and Antibacterial Poly(lactic acid) Nanofibrous Air Filters by Surface Engineering of Ultrasmall Electroactive Nanohybrids

“…However, the ZIF-8 normally displays corresponding characteristic diffraction peaks at 7.3°, 12.8°, 18.1°, and 22.2°. , Obviously, the diffraction peaks of ZIF-8 nanocrystals were shifted to the right in the BTO@ZIF-8 nanohybrids, indicating that the utilization of surface-functionalized BTO leads to the decreased crystal plane spacing of ZIF-8. It is deduced that BTO@ZIF-8 nanohybrids with high structural integrity and crystallinity probably exhibited enhanced electroactivity, adsorption, and antibacterial activity. , …”

“…It is deduced that BTO@ZIF-8 nanohybrids with high structural integrity and crystallinity probably exhibited enhanced electroactivity, adsorption, and antibacterial activity. 40,41 Antibacterial Performance of BTO@ZIF-8. The broadspectrum antibacterial activity of BTO@ZIF-8 was assessed by counting the antibacterial rates against Gram-negative (E. coli) and Gram-positive bacteria (S. aureus).…”

Recent Advances in Functional Hydrogels for Treating Dental Hard Tissue and Endodontic Diseases

“…Clinical tooth whitening techniques are usually divided into invasive whitening and noninvasive whitening, − which will cause irreversible damage to teeth and a series of adverse reactions, such as tooth sensitivity, gum irritation, and even acute pulpitis. − Given the many shortcomings of clinical tooth whitening techniques, researchers have developed many safe and reliable whitening methods. ,,, For instance, Wang et al successfully realized tooth whitening through the piezocatalysis effect of piezoelectric materials . Due to the non-centrosymmetric distribution of positive and negative electric charges in the unit cell of a piezoelectric material, under pressure and mechanical vibrations, the piezoelectric materials will create separated electron–hole pairs that react with hydroxyl ions and oxygen molecules to generate superoxide ( • O 2 – ) and hydroxyl ( • OH) radicals, and the generated • O 2 – and • OH as reactive oxygen species (ROS) can efficiently degrade organic dyes into colorless small molecules, − showing great application prospects.…”

Reactive oxygen species for therapeutic application: Role of piezoelectric materials

“…6D). 133 Almost exact simulation has been applied, compared to real brushing in a repetitive manner to stimulate the polylactide particles in water electrolyte for producing adequate voltage signals to sustain such polarization charges which is capable of associating with water molecules and oxygen to generate ROS.…”