Antimicrobial effect and transdentinal diffusion of new intracanal formulations containing nitrofurantoin or doxycycline

The effectiveness of single antibiotic paste nitrofurantoin V/S double antibiotic paste in alleviation of post-operative pain of patients suffering from symptomatic irreversible pulpitis-A randomized controlled trial

Objective

The present research evaluated and compared effectiveness between nitrofurantoin and double antibiotic paste in alleviating post-operative pain in patients suffering from symptomatic irreversible pulpitis.

Methods

There were 60 subjects enrolled who were allotted among three groups: Group 1 - Nitrofurantoin, Group 2 - double antibiotic paste, and Group 3 - Control. Succeeding access opening and chemo mechanical preparation, intracanal medicament was placed in the root canals. Using a numerical pain scale, pain scores were measured at the following time intervals: preoperative, 12, 24, 48, and 72 h. One-way ANOVA and post hoc statistical analysis were conducted, with a p-value of ⩽ considered as statistically significant.

Results

Preoperatively, most patients experienced moderate to severe pain. The patients in groups 1 and 2 reported considerable reduction in their pain scores (p ⩽ 0.001) on each time interval. However, patients in group 3 experienced a higher level of pain even at 72 h. No considerable distinction was found among participant's pain scores of groups 1 and 2 (p = 0.193).

Conclusion

For effective pain-relieving, both nitrofurantoin and double antibiotic paste can be successfully used in patients suffering from symptomatic irreversible pulpitis. However, when calcium hydroxide was used, patients experience high levels of pain.

Antibacterial and Cytotoxicity of Root Canal Sealer with the Addition of Chitosan Nanoparticle at Various Concentrations

OBJECTIVES

 The aim of this study was to evaluate the addition of chitosan nanoparticle with concentrations of 0, 10, 20, and 30% to the epoxy resin-based (ERB) sealer on its antibacterial and cytotoxicity effect.

METHODS AND MATERIALS

 This research was divided into two studies, the first study was the addition of chitosan with a concentration of 0% (as control), 10, 20, and 30% to an ERB sealer on its antibacterial effect, and the second study was on its cytotoxicity. An agar diffusion test was employed to determine the antibacterial effect on Enterococcus faecalis. An MTT (3-{4,5-dimethylthiazol-2-yl}-2,5-diphenyl tetrazolium bromide) assay was utilized to test the cytotoxicity by evaluating cell viability.

STATISTICAL ANALYSIS

 One-way analysis of variance and Tukey's test (α = 0.05) were used to analyze data obtained from each evaluation with a significance level of 95%.

RESULTS

 The addition of chitosan nanoparticles at concentrations 10, 20, and 30% produced a greater inhibition zone of E. faecalis (p < 0.05), however, had less cytotoxicity compared with no addition of chitosan (0%) (p < 0.05).

CONCLUSION

 The addition of chitosan nanoparticles at concentrations 10, 20, and 30% to the ERB sealer produced greater antibacterial and less cytotoxicity compared with no addition of chitosan (0%).

Effect of Different Intracanal Medicaments on the Viability and Survival of Dental Pulp Stem Cells

Background: Stem cells play an important role in the success of regenerative endodontic procedures. They are affected by the presence of medicaments that are used before the induction of bleeding or the creation of a scaffold for endodontic regeneration. This study examines the effects of different intracanal medicaments on the viability and survival of dental pulp stem cells at different doses and over different exposure times. Methods: Dental pulp stem cells were cultured from healthy third molar teeth using the long-term explant culture method and characterized using flow cytometry and exposed to different concentrations of calcium hydroxide, doxycycline, potassium iodide, triamcinolone, and glutaraldehyde, each ranging from 0 (control) to 1000 µg/mL. Exposure times were 6, 24, and 48 h. Cell viability was measured using the MTT assay, and apoptosis was measured using the Annexin V-binding assay. Results: All medicaments significantly reduced cell viability at different concentrations over different exposure times. Calcium hydroxide and triamcinolone favored cell viability at higher concentrations during all exposure times compared to other medicaments. The apoptosis assay showed a significant increase in cell death on exposure to doxycycline, potassium iodide, and glutaraldehyde. Conclusion: The intracanal medicaments examined in our study affected the viability of dental pulp stem cells in a time and dose-dependent manner. They also adversely affected the survival of dental pulp stem cells. Further studies are needed to better understand the effect of prolonged exposure to medicaments according to clinical protocols and their effect on the stemness of dental pulp stem cells.

The Application of Small Molecules to the Control of Typical Species Associated With Oral Infectious Diseases

Oral microbial dysbiosis is the major causative factor for common oral infectious diseases including dental caries and periodontal diseases. Interventions that can lessen the microbial virulence and reconstitute microbial ecology have drawn increasing attention in the development of novel therapeutics for oral diseases. Antimicrobial small molecules are a series of natural or synthetic bioactive compounds that have shown inhibitory effect on oral microbiota associated with oral infectious diseases. Novel small molecules, which can either selectively inhibit keystone microbes that drive dysbiosis of oral microbiota or inhibit the key virulence of the microbial community without necessarily killing the microbes, are promising for the ecological management of oral diseases. Here we discussed the research progress in the development of antimicrobial small molecules and delivery systems, with a particular focus on their antimicrobial activity against typical species associated with oral infectious diseases and the underlying mechanisms.

A critical analysis of research methods and experimental models to study tooth discolouration from endodontic materials

As a range of materials used in endodontics may cause tooth discolouration, exploration of factors responsible for the darkening of the tooth crown or root is warranted. This narrative review paper discusses the range of technical factors that apply in laboratory studies that assess endodontic discolouration. As an example of how these factors operate, particular examples relating to discolouration caused by endodontic medicaments containing tetracycline antibiotics are used. Following the PRILE 2021 guidelines approach, a summary of key variables to be addressed in the methodology for laboratory studies is presented, to inform future work.

Small Molecule Compounds, A Novel Strategy against Streptococcus mutans

Dental caries, as a common oral infectious disease, is a worldwide public health issue. Oral biofilms are the main cause of dental caries. Streptococcus mutans (S. mutans) is well recognized as the major causative factor of dental caries within oral biofilms. In addition to mechanical removal such as tooth brushing and flossing, the topical application of antimicrobial agents is necessarily adjuvant to the control of caries particularly for high-risk populations. The mainstay antimicrobial agents for caries such as chlorhexidine have limitations including taste confusions, mucosal soreness, tooth discoloration, and disruption of an oral microbial equilibrium. Antimicrobial small molecules are promising in the control of S. mutans due to good antimicrobial activity, good selectivity, and low toxicity. In this paper, we discussed the application of antimicrobial small molecules to the control of S. mutans, with a particular focus on the identification and development of active compounds and their modes of action against the growth and virulence of S. mutans.

A Novel Small Molecule, ZY354, Inhibits Dental Caries-Associated Oral Biofilms

Biofilm control is a critical approach to the better management of dental caries. Antimicrobial small molecules have shown their potential in the disruption of oral biofilm and control of dental caries. The objectives of this study were to examine the antimicrobial activity and cytotoxicity of a newly designed small-molecule compound, ZY354. ZY354 was synthesized, and its cytotoxicity was evaluated in human oral keratinocytes (HOK), human gingival epithelial cells (HGE), and macrophages (RAW) by CCK-8 assays. Minimal inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), minimum biofilm inhibition concentrations (MBICs), and minimum biofilm reduction concentrations (MBRCs) of ZY354 against common oral streptococci (i.e., Streptococcus mutans, Streptococcus gordonii, and Streptococcus sanguinis) were determined by microdilution method. The exopolysaccharide (EPS)/bacterium ratio and the dead/live bacterium ratio in the ZY354-treated multispecies biofilms were determined by confocal laser scanning microscopy, and the microbial composition was visualized and quantified by fluorescent in situ hybridization and quantitative PCR (qPCR). The demineralizing activity of ZY354-treated biofilms was evaluated by transverse microradiography. The results showed that ZY354 exhibited low cytotoxicity in HOK, HGE, and RAW cells and exhibited potent antimicrobial activity against common oral streptococci. The EPS and the abundance of S. mutans were significantly reduced after ZY354 treatment, along with an increased dead/live microbial ratio in multispecies biofilms compared to the level with the nontreated control. The ZY354-treated multispecies biofilms exhibited reduced demineralizing activity at the biofilm/enamel interface. In conclusion, the small-molecule compound ZY354 exhibits low cytotoxicity and remarkable antimicrobial activity against oral streptococci, and it may have a great potential in anticaries clinical applications.

Microhardness evaluation of silorane and methacrylate composites submitted to erosion and abrasion processes

Objective: The aim of this study was to evaluate the Knoop hardness number (KHN) of methacrylate (MC) and silorane (SC) composites after being submitted to erosion and abrasion processes. Material and methods: Forty samples were made with each composite: MC and SC. The samples were divided into eight groups (n = 10) according to the type of composite (G1-G4, MC; G5-G8, SC) and the beverages involved in the erosion process (G1 and G5 - Control (C), without erosion, with abrasion; G2 and G6 - Orange Juice (OJ), abrasion; G3 and G7 - Smirnoff Ice® (SI), abrasion; G4 and G8 - Gatorade® (GA), abrasion). The KHN test was performed 24 h after the last cycle of erosion/abrasion. Results: The MC groups showed smaller KHN values for the SI group (p < 0.05) when compared to the Control and OJ groups; however, for the SC groups, no differences were found (p > 0.05). Conclusion: Methacrylate composite when submitted to acidic beverages erosive challenge combined with abrasive process might alter its surface microhardness. However, the beverages used in the present study were not able to interfere in silorane composite surface microhardness.