A novel zinc oxide eugenol modified by polyhexamethylene biguanide: Physical and antimicrobial properties

Abstract

This study was to prepare and screen a novel root canal sealing agent modified by polyhexamethylene biguanide (PHMB) that was in accordance with the ISO 6876:2001 standard and to study its physical and antimicrobial properties. The modified sealers were produced by mixing a certain amount of zinc oxide with eugenol containing different concentrations of PHMB (0.05, 0.1, 0.2, 0.4, 0.6 and 0.8%) at a ratio of 1:1 (w/v). The setting time, flow, film thickness, solubility and dimensional change after solidifying were assessed to screen out the modified sealing agents that the physical properties met the mentioned standards. The modified direct contact test (DCT) was used to evaluate the antimicrobial activity against Enterococcus faecalis. The results suggested that when the concentrations of PHMB were 0.05, 0.1 and 0.2%, the modified root canal sealers showed the best performance in physical and antimicrobial properties.

Mechanical, antibacterial, biocompatible and microleakage evaluation of glass ionomer cement modified by nanohydroxyapatite/polyhexamethylene biguanide

“…In second mechanical test, CS, VHN, and ST became lower with PHMB incorporated compared to GIC/6%NHA. The decline of mechanical properties corresponds with our previous study 27) , this may lie in that PHMB, as organic polymers, affected the integrity of the inorganic material, resulting in weak zones in the matrix. In SEM images, more voids and cracks could be seen when more PHMB was added.…”

“…Though the OD value of culture medium has been subtracted, it still could trigger mass disperse to the true situation as the OD value is not calculated in a linear model. The persistent downward of antibacterial effect of many dental materials is a common problem 3,4) , while several studies 27,46) have indicated PHMB's potential for the long-term disinfectant activity when applied in dental materials, yet it has not been systematically investigated. In our previous study 27) , the AR of ZOE modified by 0.2% PHMB remained 85.2% after 14 days.…”

“…The persistent downward of antibacterial effect of many dental materials is a common problem 3,4) , while several studies 27,46) have indicated PHMB's potential for the long-term disinfectant activity when applied in dental materials, yet it has not been systematically investigated. In our previous study 27) , the AR of ZOE modified by 0.2% PHMB remained 85.2% after 14 days. This long-lasting effect could be attributed to PHMB's strong adsorption into dentinal tubules, which helps keep a sterile environment and avoid reinfection 47) .…”

“…All these features suggest it a potential choice for modification. Our previous study 27) indicated that PHMB modified eugenol oxide (ZOE) root canal sealer had have its long-term antibacterial performance greatly improved and meanwhile setting time shortened. However, as organic polymers, PHMB will affect the integrity of the inorganic material when doped in, resulting in the slight decrease of mechanical properties.…”

A comparative study of dentinal tubule penetration and the retreatability of EndoSequence BC Sealer HiFlow, iRoot SP, and AH Plus with different obturation techniques

“…This may be related to the low film thickness of HiFlow at both room and high temperatures [ 25 ], which is regarded as an important physical property for sealers. Previous studies indicated that film thickness and the flow of the sealers were related to the ability to fill root canals successfully [ 59 , 60 ]. Our study further suggested that sealers characterized by lower film thickness and a better flow ability might present improved convenience regarding removal for retreatment cases.…”