An in Vitro Study Comparing the Effect of Nanocalcium Hydroxide Powder with Various Vehicles as Intracanal Medicaments on the Microhardness of Root Dentin

An intra-canal medicament (ICM) is a drug commonly used in endodontics to disinfect root canals between appointments. It helps eliminate residual bacteria after root canal preparation, reduces inflammation in the pulp and periapical tissues, neutralizes tissue debris, and makes canal contents inert. Additionally, it acts as a barrier alongside the temporary filling to prevent leakage and facilitates the drying of persistently wet canals. Therefore, the use of an ICM is essential for creating a microbe-free environment before root canal obturation, promoting optimal healing of the periapical tissues. Recently, nano-calcium hydroxide (NCH) has been introduced in endodontics, offering superior antibacterial properties compared to traditional calcium hydroxide powder. This is due to NCH's larger surface area-to-volume ratio and increased charge density, which enhance its interaction with the environment, resulting in greater antibacterial activity. To improve the effectiveness of ICMs, various vehicles such as aqueous, viscous, and oil-based formulations are used. Polyethylene glycol, an oil-based vehicle, has antibacterial properties due to its hydrophilic nature, which helps reduce bacterial counts. Chitosan, a viscous vehicle, possesses multiple biological properties, including antibacterial, hypercholesterolemic, wound healing, mucoadhesive, and sustained-release characteristics. Chlorhexidine, an aqueous vehicle, is known for its strong antibacterial properties. These vehicles may influence the physical and chemical properties of root dentin. Microhardness testing can be used to assess potential mineral loss or gain in dental hard tissues. The aim of this study is to investigate the effect of nano-calcium hydroxide combined with various vehicles on the microhardness of root dentin.