Ervin Itzchak Weiss

Antibacterial temporary restorative materials incorporating polyethyleneimine nanoparticles.

OBJECTIVES Temporary restorative materials (TRMs) often rapidly lose their dimensional stability and antibacterial properties after exposure to humidity and bacterial infection. Quaternary ammonium polyethyleneimine (QPEI) nanoparticles (NP) are long-lasting, stable, biocompatible, and nonvolatile antibacterial polymers. In the present study, we incorporated QPEI NP into standard TRMs and examined their influence on dimensional stability and their ability to reduce bacterial leakage. METHOD AND MATERIALS A modified split-chamber model was used in vitro to test calcium sulfate-based and zinc oxide-eugenol- based TRMs (Coltosol and IRM, respectively). Both materials were tested with and without 2% wt/wt incorporated QPEI NP for fluid and bacterial leakage. RESULTS The calcium sulfate-based TRM displayed the lowest microleakage and highest antibacterial resistance. Two-way A NOVA analysis of the fluid transport test results showed that incorporation of 2% wt/wt QPEI NP significantly increased the sealing ability of both TRMs (P < .01). Analysis of survival curves by the Kaplan-Meier method showed that the calcium sulfate-based TRM with 2% wt/wt QPEI NP survived the bacterial load significantly more effectively than did the zinc oxide-eugenol-based TRM (P < .0001). CONCLUSION Incorporation of 2% w/w QPEI NP may prominently improve the sealability and the antibacterial properties of TRMs. TRMs incorporating antibacterial nanoparticles may be clinically advantageous for sealing the endodontic access cavity to avoid reinfection of the root canal system during endodontic treatment.

Day-long reduction of oral malodor by a palatal mucoadhesive tablet containing herbal formulation

Previous research has shown the oral malodor reducing abilities of an herbal formulation delivered using a palatal mucoadhesive tablet. The aim of the present study was to test the day-long effect of this preventive treatment on oral malodor reduction as compared with placebo and commercial mouthwash. Forty young healthy subjects (mean age, 25.8 ± 1.8 yrs, 19 females) presenting with oral malodor were randomly assigned to use one of the three tested products: herbal mucoadhesive tablets, placebo mucoadhesive tablets and a commercial mouthwash. Following baseline measurements, subjects were instructed to use the products in the evening of the same day and the following morning. Baseline and follow-up measurements were conducted in the afternoon and included odor judge scores (two judges), volatile sulfide compounds (VSC) levels using a sulfide monitor (Halimeter™) and saliva sample for β-galactosidase activity assay. The herbal mucoadhesive tablet caused a significant reduction in malodor scores (p = 0.004), VSC levels (p = 0.002) and β-galactosidase assay (p = 0.02) as compared to the placebo, and reduced malodor level to below the clinical threshold (mean odor judge score of 1.7). These results demonstrate the efficacy of the herbal formulation delivered using a mucoadhesive tablet for day-long prevention of oral malodor.

Chapter 3 – Antimicrobial Nanoparticles in Restorative Composites

Publisher Summary This chapter discusses use of nanoparticles in making restorative composites for dentistry purpose. Restorative composite materials are commonly used in dentistry as hard tissue substitute. Recent studies have shown that incorporation of quaternary ammonium PEI (QPEI) nanoparticles in a resin composite has a long-lasing antimicrobial effect against a wide range of bacteria with no apparent negative effect on biocompatibility. QPEI nanoparticles are found to have a strong bactericidal activity against Streptococcus mutans and a wide variety of microorganisms rapidly killing bacterial cells when incorporated at small concentrations into restorative composites. QPEI nanoparticles have a potential to be incorporated into dental resin-based restorative materials to provide bactericidal activity without causing adverse effect on physiologic properties or on biocompatibility. This chapter begins with a discussion on antibacterial restorative composites and then elaborates basic concepts related to filler phase modification, matrix phase modification, released antibacterial agents, and nonreleased antibacterial agents. The chapter also discusses about antimicrobial macromolecules. The chapter concludes with a discussion on nanoparticles and their synthesis.