Biosafety and chemical solubility studies of multiscale crystal‐reinforced lithium disilicate glass‐ceramics

Abstract

Lithium disilicate (Li2Si2O5) glass‐ceramics are currently a more widely used all‐ceramic restorative material due to their good mechanical properties and excellent aesthetic properties. However, they have a series of problems such as high brittleness and low fracture toughness, which has become the main bottleneck restricting its development. Therefore, in order to compensate for these shortcomings, we propose to prepare a reinforced glass‐ceramics with better mechanical properties and to test the biosafety and chemical solubility of the material. Li2Si2O5 whiskers were synthesized by a one‐step hydrothermal method, and multi‐scale crystal‐enhanced Li2Si2O5 glass‐ceramics were prepared by reaction sintering. The biosafety of multi‐scale crystal‐reinforced Li2Si2O5 glass‐ceramics was investigated by in vitro cytotoxicity test, rabbit pyrogen test, mice bone marrow micronucleus test, skin sensitization test, sub‐chronic systemic toxicity test, and chronic systemic toxicity test. Additionally, the chemical solubility of multi‐scale crystal‐reinforced Li2Si2O5 glass‐ceramics was investigated. The test results showed that the material was non‐cytotoxic, non‐thermogenic, non‐mutagenic, non‐sensitizing, and non‐systemic. The chemical solubility, determined to be 377 ± 245 μg/cm2, complied with the ISO 6872 standard for the maximum solubility of ceramic materials. Multi‐scale crystal‐reinforced Li2Si2O5 glass‐ceramics' biosafety and chemical solubility met current normative criteria, and they can move on to mechanical property measurements (such as flexural strength test, fatigue life test, friction and wear property study, etc.) and bonding property optimization, which shows promise for future clinical applications.

Recent Advances in Whiskers: Properties and Clinical Applications in Dentistry

“…Common solid-phase methods for preparing whiskers include hot pressing, 56 melting, 177 and reaction methods. 47 Hot pressing involves heating the raw materials to high temperatures and reacting and sintering them under pressure to finally form whiskers. This method is suitable for preparing high-purity and high-crystallinity whiskers, such as oxides and carbides.The melting method involves heating the raw material above the melting point to form a molten state and then forming whiskers by controlling the cooling rate and crystallization conditions.…”

“…Ceramic whiskers with high strength and good biocompatibility can be used as biomaterials to replace diseased or damaged tissues. For example, they can be used to make artificial joints, 218 , 219 teeth, 47 , 220 and bones. 221–225 Metal whiskers can be used to prepare biosensors and medical devices to improve the sensitivity and biocompatibility of the devices.…”

“…The assessment includes but is not limited to, in-depth studies of the biocompatibility of whiskers with oral tissues and cells to ensure that the material does not cause adverse reactions or rejection in the oral environment. 47 , 48 In addition, toxicological testing is required to clarify whether the material has any potential toxic or adverse effects on the human body. 49 , 50 Therefore, the clinical application of whiskers has a long way to go, and much effort is needed to enhance its clinical breakthrough.…”