Effect of Final Irrigation Solutions on Mechanical Properties of Root Canal Dentine Running title: Final Irrigation on Mechanical Properties.

OBJECTIVES: The final irrigation solution should have the capability of a chelation agent to remove the smear layer. The purpose of this study was to determine the effect of EDTA, novel silver citrate, and chitosan nanoparticles as a final irrigation solution on the mechanical properties of root canal dentine, namely the flexural strength and elastic modulus. METHODS: Thirty-two intact, single, and straight roots, with no caries, no cracks, and no restoration of premolars, were assigned into four groups of 8 teeth each. Group 1: irrigated with EDTA; Group 2: irrigated with novel silver citrate; Group 3: irrigated with chitosan nanoparticles; Group 4: irrigated with saline as control. Using a Universal Testing Machine, each sample was tested for flexural strength and elastic modulus with a three-point bend test. The data were analysed using one-way ANOVA and followed by the Tukey's test with a significance level of 95%. RESULTS: Chitosan nanoparticles generated the highest flexural strength and elastic modulus of root canal dentine (212.03 +- 1.64 and 16.40 +- 1.05, respectively) than EDTA (127.10 +- 0.90 and 7.37 +- 0.94) and novel silver citrate (177.87 +- 2.03, and 12.27 +- 1.01) (p<0.05). However, chitosan nanoparticles have similar flexural strength and elastic modulus of root canal dentine when compared to saline (213.76 +- 1.48, 17.02 +- 1.14, respectively) (p>0.05). CONCLUSION: Among final irrigations used, chitosan nanoparticles produced the highest flexural strength and elastic modulus of root canal dentine compared to EDTA and novel silver citrate.

The Potential of QP3VH-Chitosan Peptide as Biomimetic Remineralization in Early Dental Caries Treatment: An In Vitro Study.

OBJECTIVES: The development of remineralization biomimetics using organic peptide molecules is expected to resemble the hydroxyapatite (HA) mineralization process in tooth enamel. The development of an amelogenin derivative peptide combined with antimicrobial peptide was designed, resulting in QP3VH. This combination then was mixed with chitosan as a carrier. This study aimed to evaluate the biomimetic efficacy of QP3VH as a remineralizing agent combined with chitosan. MATERIALS AND METHODS: Fifty deciduous mandibular incisor enamel samples were used in this study. The artificial enamel lesions were created on a buccal surface and were randomly assigned to five groups of 10 each according to the remineralizing agent used: QP3VH, NaF, QP3VH + NaF, QP3VH + CS (QP3VH + chitosan), and saline distilled water (SDW). Each group was performed pH cycling for seven days. Enamel surface morphology and evaluation of mineral content Ca/P (calcium and phosphate) using scanning electron microscopy and energy dispersive X-ray analysis. The assessment was carried out, after demineralization, and after application with remineralization agents. STATISTICAL ANALYSIS: Data were analyzed using a one-way analysis of variance followed by least significance difference post-hoc test. The paired t-test was utilized to compare the demineralization and remineralization results. The significance level used was 95%. RESULTS: The remineralized group exhibited a significant increase in calcium and phosphate content on the enamel surface (p <0.05), and QP3VH + CS produced the maximum Ca/P mass percent after remineralization. CONCLUSION: Combining QP3VH with chitosan produces greatest remineralization than QP3VH, QP3VH + NaF, Naf, and SDW; therefore, QP3VH peptide has potential as a remineralizing agent, in the future.

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%).

Antibacterial efficacy, calcium ion release, and pH using calcium hydroxide with three vehicles.

Context: Vehicles combined with calcium hydroxide, as an intracanal medicament, play a key factor in affecting antibacterial, calcium release, and pH. Aims: The aim of this study is to investigate the effect of three vehicles (glycerin, chlorhexidine gluconate/CHX, and chitosan nanoparticle) combined with calcium hydroxide as an intracanal medicament on antibacterial efficacy against Enterococcus faecalis, calcium ion release, and pH of at different interval times of 7 and 14 days. Settings and Design: The research was experimental laboratory. Materials and Methods: Each study used 24 samples of eight teeth each and was randomly divided into three groups based on the vehicle of calcium hydroxide: group 1: glycerin, group 2: CHX, and group 3: chitosan nanoparticles. Each vehicle group was then further divided into two subgroups of four teeth based on the interval times (group A: 7 days and group B: 14 days). The antibacterial efficacy was determined using an agar diffusion method. Calcium ion release was analyzed with atomic absorption spectrometry, and pH was measured using a pH meter. Statistical Analysis Used: Data from each study were analyzed by two-way ANOVA, followed by Tukey's test with a significance level of 95%. Results: The results exhibited that chitosan nanoparticles had the highest antibacterial efficacy against E. faecalis, calcium ion release, and pH, while the lowest was glycerin at 7 and 14 days (P < 0.05). Conclusion: Calcium hydroxide combined with chitosan nanoparticle as an intracanal medicament produced the highest antibacterial efficacy against E. faecalis, calcium ion release, and pH than glycerin and CHX at intervals of 7 and 14 days.

Time-Dependent Effect of Chitosan Nanoparticles as Final Irrigation on the Apical Sealing Ability and Push-Out Bond Strength of Root Canal Obturation.

MATERIALS AND METHODS: Fifty-six premolars were used in this study and divided by two evaluations: 28 teeth for apical sealing ability and 28 others for bond strength. Each study was assigned randomly into two groups of fourteen teeth: Group-1, final irrigation with 17% EDTA; Group-2, with 0.5% chitosan nanoparticles. Each group was further divided into two groups of 7 each: Group-A, final irrigation was applied for 1 minute; Group-B, for 3 minutes. All teeth were obturated with epoxy resin-based sealer and gutta-percha. In the apical sealing ability study, the obturated teeth were immersed in 2% methylene blue and observed under a stereomicroscope (8x magnification). In the bond strength study, the teeth were tested using the push-out technique and observed under a stereomicroscope (40x magnification) to determine the failure type. Data from each evaluation were analysed with two-way ANOVA followed by the LSD test. RESULTS: Final irrigation using 0.5% chitosan nanoparticles produced the same apical sealing ability and bond strength as 17% EDTA (p > 0.05). A significant difference occurred between application times (p < 0.05). The failure type was observed predominantly as cohesive, and the least was adhesive. CONCLUSION: Regardless of the final irrigation solution used, 3-minute application time produced greater apical sealing ability and push-out bond strength than 1-minute application time.