Antimicrobial effect of Red Roselle (Hibiscus Sabdariffa) against different types of oral bacteria.

This study aimed to compare the antimicrobial effect of an aqueous extract Red Roselle calyx (RE), Chlorhexidine (CH), Amoxicillin-clavulanic acid (ACA), Tetracycline (Tet), and Metronidazole (Met)on Streptococcus mutans (S. mutans), Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis) bacteria. The bacterial inhibition zones (BIZ)of the RE (25, 50, 75, 100) mg/ml and CH solutions (0.2%, 2%) were determined using the agar well diffusion method. Additionally, the susceptibility of the tested bacteria against (30 µg) of standard antibiotics of ACA, Tet, and Met was examined. The bacterial minimum inhibitory concentration (MIC) was measured using the Broth Micro dilution method (BMDM). All tests were carried out in triplicates, and water was considered the negative control. For S. mutans, the RE at 50 mg/ml or above concentrations displayed higher BIZ than 0.2% CH. 100 mg/ml of RE recorded a greater BIZ than the 2% CH. The greater BIZ against S. mutans was recorded by Tet. A comparable effect was found with 0.2% CH (75, 100) mg/ml of the RE against S. aureus. Greater BIZ for S. aureus and E. faecalis were reported for 100 mg/ml RE compared to the Tet and Met RE at 100 mg/ml inhibited the E. faecalis growth in a zone size comparable to the CH (0.2%, 2%).The RE with 50,100 mg/ml concentrations showed comparable antimicrobial effect to 0.2%, 2% concentrations of CH, respectively. As an herbal substitute for commercial disinfectants, the RE can be considered an effective final endodontic irrigant and dental mouthwash.

Studying Effects of Calcium Oxide Nanoparticles on Dentinogenesis in Male Wistar Rats.

This study aimed to evaluate potential impacts of calcium oxide nanoparticles (CaO-NPs) at different dosages on predentin thickness, number of blood vessels, periodontal ligament thickness, and blood glucose level of Wistar rats. Twelve rats were randomly gathered into four groups, untreated (control) and CaO-NP-treated groups at three concentrations (25, 50, and 100 mg/kg of the body weight) over a period of 60 days. Histological investigation was performed on twenty-four lower incisor teeth extracted from all the tested groups under a light microscope, and an automatic Fujifilm was used to measure the blood glucose level. The results showed that regular nanoparticle treatment significantly increased predentin and periodontal ligament thicknesses, a gradual decrease in vascularization in the pulp tissue, and an increase in the blood glucose level as the dosages of nanoparticles administered to the rats increased. Administration of the CaO-NPs at low dosage (25 mg/kg) could be beneficial for the growth and integrity of teeth and dentinal tissues in rats.

Chemical Characterisation of Silanised Zirconia Nanoparticles and Their Effects on the Properties of PMMA-Zirconia Nanocomposites.

Objectives: The objective of this study was to investigate the mechanical properties of high-impact (HI) heat-cured acrylic resin (PMMA) reinforced with silane-treated zirconia nanoparticles. Methods: Forty-five PMMA specimens reinforced with zirconia were fabricated and divided into three groups: Pure HI PMMA (control group), PMMA reinforced with 3 wt.% of non-silanised zirconia nanoparticles and PMMA reinforced with 3 wt.% of silanised zirconia nanoparticles. Silanised and non-silanised zirconia nanoparticles were analysed with Fourier Transform Infrared (FTIR) Spectroscopy. For measuring the flexural modulus and strength, a Zwick universal tester was used, and for surface hardness, a Vickers hardness tester were used. Furthermore, raw materials and fractured surfaces were analysed using Scanning Electron Microscopy (SEM). A one-way ANOVA test followed by a post-hoc Bonferroni test was employed to analyse the data. Results: The results showed that the mean values for flexural strength (83.5 ± 6.2 MPa) and surface hardness (20.1 ± 2.3 kg/mm2) of the group containing 3 wt.% treated zirconia increased significantly (p < 0.05) in comparison to the specimens in the group containing non-treated zirconia (59.9 ± 7.1 MPa; 15.0 ± 0.2 kg/mm2) and the control group (72.4 ± 8.6 MPa; 17.1 ± 0.9 kg/mm2). However, the group with silanised zirconia showed an increase in flexural modulus (2313 ± 161 MPa) but was not significantly different (p > 0.05) from the non-silanised group (2207 ± 252 MPa) and the control group (1971 ± 235 MPa). Conclusion: Silane-treated zirconia nano-filler improves the surface hardness and flexural strength of HI PMMA-zirconia nanocomposites, giving a potentially longer service life of the denture base.

Evaluating In Vitro Performance of Novel Nickel-Titanium Rotary System (TruNatomy) Based on Debris Extrusion and Preparation Time from Severely Curved Canals.

INTRODUCTION: This laboratory-based study aimed to investigate the quantitative amount of apically extruded debris from severely curved root canals and the preparation time for the novel rotary system TruNatomy (TN; Dentsply Sirona, Charlotte, NC) compared with Reciproc Blue (RCB; VDW Dental, Munich, Germany), HyFlex (HyFlex Controlled Memory [HCM; Coltene/Whaledent, Altstatten, Switzerland] and HyFlex EDM [HEDM, Coltene/Whaledent]), and ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland) rotary systems. METHODS: One hundred mandibular molar human teeth with severe curvature of the mesiobuccal canal (25°-45°) were included in the present study. The specimens were randomly distributed into 5 balanced groups (n = 20): TN, RCB, HCM, PTN, and HEDM. The amount of extruded debris for each group during instrumentation at body temperature was collected in an Eppendorf tube. After desiccation, the mean debris weights for each group were calculated. The total preparation time for each group was also recorded. Data were statistically analyzed using the Kruskal-Wallis test at a significance level of P < .05. RESULTS: The HCM and HEDM groups extruded a significantly higher amount of debris than the other tested groups (P < .001). TN extruded the least amount of debris, but it was not significantly different compared with the RCB and PTN groups (P > .05). In terms of preparation time, the TN group did not show any significant difference compared with the other groups. CONCLUSIONS: All instrumentation systems extruded debris. TN was among the groups that produced the lowest amount of apically extruded debris that is clinically acceptable. The amount of apically extruded debris using the TN system was equal to 2 popular systems and statistically significantly less than 2 other popular systems studied.

Impact of Peracetic Acid on the Dynamic Cyclic Fatigue of Heat-Treated Nickel-Titanium Rotary Endodontic Instrument.

Peracetic acid (PAA) is widely used as a sterilizing/disinfecting agent, and, in endodontics, it has been introduced as a promising irrigant in root canal treatment. It has been used at different concentrations to achieve various functions. However, endodontic instruments in contact with PAA of a certain concentration may affect their fatigue resistance. Therefore, the aim of this study was to investigate the impact of PAA on the cyclic fatigue resistance of three commercial heat-treated nickel-titanium (NiTi) rotary files. Three types of heat-treated NiTi rotary files were selected: One Curve (OC), ProTaper Gold (PTG), and Wave One Gold (WOG). Each type was divided into three subgroups (n = 6 for each file type): (1) untreated instruments; (2) files immersed in 0.002% PAA; and (3) files immersed in 0.35% PAA. The performance of each file type was tested in a simulated canal. The number of cycles to fracture (NCF) was determined to assess cyclic fatigue resistance of the files. Independent sample t-test was applied to compare each treated file within a subgroup with its respective control group, and one-way ANOVA was used for comparison among the main groups. All types of tested files revealed a significant decline in the cyclic fatigue resistance after exposure to 0.002% PAA except the PTG (P=0.209). After exposure of the files to a higher concentration (0.35% PAA), a dramatic reduction was demonstrated by all the groups. Before and after exposure of the files to PAA, PTG displayed the highest cyclic fatigue resistance, followed by the WOG, while the OC showed the lowest resistance. Exposure of heated-treated NiTi files to PAA in a relatively high or low concentration adversely affects the cyclic fatigue resistance. The PTG files demonstrated the best performance among the tested types and can be disinfected with 0.002% PAA for clinical purpose.

The Effect of Biodentine Maturation Time on Resin Bond Strength When Aged in Artificial Saliva.

Biodentine is a calcium silicate cement (CSC) that has been broadly applied in vital pulp therapy. The quality of the Biodentine-composite bond has a significant effect on the longevity of the definitive restoration. The aim of this study is to investigate the shear bond strength (SBS) between Biodentine and composite restoration at different maturation times of Biodentine aged in artificial saliva. Fifteen Biodentine discs were allocated into three groups (n = 5) based on the timeframe of performance of composite restoration: immediate (after 12 min), after 14 days, and after 28 days of Biodentine maturation. Total etch and rinse adhesive system and bulk-fill regular resin composite were used. The shear bond strength and the failure pattern were assessed. One-way ANOVA with the Bonferroni post hoc test was applied for statistical analysis at p < 0.05. The highest (32.47 ± 8.18 MPa) and the lowest (4.08 ± 0.81 MPa) SBS values were recorded for 14 days and 12 min groups, respectively. Significant statistical differences were reported among the groups, and a high statistically significant difference was found between the immediate group and the other groups. Adhesive failure patterns were evident in all groups. More clinically acceptable bond strength between the Biodentine and overlaid composite restoration is at 14 days after Biodentine maturation. Delaying the coverage of Biodentine later than 14 days may significantly reduce the SBS. Using the artificial saliva as an aging medium may affect the SBS between Biodentine and composite material.

Effect of the Composition of CAD/CAM Composite Blocks on Mechanical Properties.

The aim of this study was to evaluate the effect of the composition of CAD/CAM blocks on their mechanical properties. Nine different CAD/CAM blocks, enamel and dentine, were tested. Sixteen samples of each material were separated for Vickers microhardness test (n=6, 5 readings per specimen), nanohardness test (n=6, 5 readings per specimen), filler weight (n=3), and SEM imaging (n=1). Data were statistically analysed using one-way ANOVA. Vita Mark II ceramic showed significantly higher values of hardness (in both nano- and microscale) and elastic modulus (6.83 GPa, 502 kg/mm2, and 47.7 GPa), respectively, than other materials. CAD/CAM composite blocks showed comparable values of hardness and elastic modulus to those of dentine but lower than those of enamel and ceramics. SEM images highlighted different filler-matrix microstructure of CAD/CAM composite blocks. It was concluded that (1) hardness and elastic moduli are positively correlated with ceramic filler percentage and microstructure and (2) CAD/CAM composite materials have comparable hardness and elastic moduli to tooth structure.