Root canal morphology and symmetry of mandibular second premolars using cone-beam computed tomography.

OBJECTIVES: The current study aims to investigate the morphology and symmetry of root canals of mandibular second premolar teeth via Cone-Beam Computed Tomography (CBCT) among a sample of the Saudi population. METHODS: A total of 1200 CBCT images were examined in the study. The number of roots in the mandibular second premolars was identified, and canal configurations were classified according to Vertucci classification. Bilateral symmetry and association between gender and number of roots and root canal configuration were investigated using a chi-square test was utilized for data analysis and p value was set at 0.05 for significance. RESULTS: Of the total 2400 Mandibular second premolars, 98.33% were single rooted and 1.67% were double rooted. The prevalence of double roots in females on the right side was significantly higher than that on the left side (p = 0.017), but the opposite was found among males. Only Type I and II canal configurations showed significant differences regarding gender and sides. 98.0% of teeth showed the symmetrical number of roots in both genders. The symmetry in canal configuration was 96.7% in males and 97.3% in females and 99.1% was Type I in both sides, 0.5% Type III, and 0.3% Type IV in both sides. CONCLUSIONS: The root morphology of mandibular second premolars in the Saudi population demonstrated a high degree of variability. The vast majority of mandibular premolars have a single root with one canal and a low prevalence of two rooted teeth. Contralateral mandibular second premolars exhibited great symmetry of roots and root canal configuration.

Dielectric properties and in vitro hemocompatibility of Nd:YAG laser-irradiated polyethylene terephthalate.

Surface properties and morphology of the biomaterial play an essential role in the polymer-material interaction. In this work, laser surface modification of polyethylene terephthalate as a polymer with distinguished mechanical properties was carried out using (neodymium-doped yttrium aluminum garnet) Nd:YAG laser (1.064 µm) with different output power (0.3, 3, and 6 W). The structural, surface, and dielectric properties of PET before and after laser irradiation have been studied using attenuation total reflection-Fourier transform infrared (ATR-FTIR), dielectric spectroscopy (DS), scanning electron microscope (SEM), and contact angle measurements. Moreover, the anticoagulant properties of the laser-irradiated PET was determined through measuring the prothrombin time (PT), partial thromboplastin time (PTT), and international normalized ratio (INR). In vitro platelet adhesion test was used to assess the platelets adhered to the surface of the samples; in addition to hematological study. It was found that contact angle (θ) measurements of laser-irradiated PET samples decreased compared to the unirradiated PET. The irradiated samples at 0.3 W have the lowest contact angle which is a clear indication that surface treatment with Nd:YAG laser brought about improving the wettability of the polymer. From the dielectric measurements, both values of permittivity and dielectric loss decrease by increasing the laser power. The electrical conductivity decreases with increasing laser power, but still in the same order 10-14 S/cm. The decrease in electrical conductivity σ may be due to the cross-linking of the polymeric matrix which led to a decrease in the total polarity and consequently decrease in electrical conductivity. The magnitude of σ obtained is highly recommended to be used for insulator purposes in addition to the main purpose that is blood contact.

Preparation and characterization of polyethylene terephthalate-chamomile oil blends with enhanced hydrophilicity and anticoagulant properties.

New blend films based on polyethylene terephthalate (PET) with different concentrations (50, 100 and 200 µL) of chamomile oil (CAO) were prepared. The effect of oil on the dielectric properties, structural and surface properties of PET was studied. The wettability of the blend films was evaluated by contact angle measurements. In vitro platelet adhesion on the surface and coagulation assessment were conducted to evaluate the behavior of the new blends for blood contact applications. Results of the study indicate that the wettability of PET-CAO blends up to 100 µL has been enhanced relative to the pure PET as indicated by the decrease in contact angle measurements. The attenuation total reflection-Fourier transform infrared spectra of the blends confirmed the presence of chamomile oil in the polymer matrix and suggested the presence of interaction between them. The permittivity ε' values decreased by increasing oil content upto 100 µL. On the other hand, the values of dielectric loss ε″ were found to increase by increasing oil content to 100 µL after which it decreased. The delay in partial thromboplastin time (PTT) of the blood would validate the anti-coagulant property of PET-CAO blends. The results demonstrated that the PET-CAO blends with concentration of 100 µL could be considered as a promising candidate material in blood contact application.

Biocompatibility enhancement of graphene oxide-silver nanocomposite by functionalisation with polyvinylpyrrolidone.

Several materials such as silver are used to enhance graphene oxide (GO) sheets antimicrobial activity. However, these toxic materials decrease its biocompatibility and hinder its usage in many biological applications. Therefore, there is an urgent need to develop nanocomposites that can preserve both the antimicrobial activity and biocompatibility simultaneously. This work highlights the importance of functionalisation of GO sheets using Polyvinylpyrrolidone (PVP) and decorating them with silver nanoparticles (AgNPs) in order to enhance their antimicrobial activity and biocompatibility at the same time. The structural and morphological characterisations were performed by UV-Visible, Fourier transform infrared (FTIR), and Raman spectroscopic techniques, X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HR-TEM). The antimicrobial activities of the prepared samples against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans were studied. The cytotoxicity of prepared materials was tested against BJ1 normal skin fibroblasts. The results indicated that the decoration with AgNPs showed a significant increase in the antimicrobial activity of GO and FGO sheets, and functionalisation of GO sheets and GO-Ag nanocomposite with PVP improved the cell viability about 40 and 35%, respectively.

Cyclic fatigue, bending resistance, and surface roughness of ProTaper Gold and EdgeEvolve files in canals with single- and double-curvature.

OBJECTIVES: The purpose of this study was to evaluate the cyclic fatigue, bending resistance, and surface roughness of EdgeEvolve (EdgeEndo) and ProTaper Gold (Dentsply Tulsa Dental Specialties) nickel-titanium (NiTi) rotary files. MATERIALS AND METHODS: The instruments (n = 15/each) were tested for cyclic fatigue in single- (60° curvature, 5-mm radius) and double-curved (coronal curvature 60°, 5-mm radius, and apical curvature of 30° and 2-mm radius) artificial canals. The number of cycles to fracture was calculated. The bending resistance of both files were tested using a universal testing machine where the files were bent until reach 45°. Scanning electron microscopy and x-ray energy-dispersive spectrometric analysis were used for imaging the fractured segments, while the atomic force microscope was used to quantify the surface roughness average (Ra). RESULTS: EdgeEvolve files exhibited higher cyclic fatigue resistance than ProTaper Gold files in single- and double-curved canals (p < 0.05) and both files were more resistant to cyclic fatigue in single-curved canals than double-curved canals (p < 0.05). EdgeEvolve files exhibited significantly more flexibility than did ProTaper Gold files (p < 0.05). Both files had approximately similar Ni and Ti contents (p > 0.05). EdgeEvolve files showed significantly lower Ra values than ProTaper Gold files (p < 0.05). CONCLUSIONS: Within the limitation of this study, EdgeEvolve files exhibited significantly higher cyclic fatigue resistance than ProTaper Gold files in both single- and double-curved canals.

Can Mineral Trioxide Aggregate and Nanoparticulate EndoSequence Root Repair Material Produce Injurious Effects to Rat Subcutaneous Tissues?

INTRODUCTION: The aim of this study was to evaluate the injurious effects of mineral trioxide Aggregate (MTA) and EndoSequence Bioceramic Root Repair Material (ERRM; Brassler USA, Savannah, GA) 7 and 30 days after their implantation into rat subcutaneous tissues. METHODS: Twelve Wistar rats were selected for the present study. Each animal received 3 implants: one contained MTA, one contained ERRM, and one was an empty tube that served as a control. Half of the animals were killed after 7 days, and the remaining animals were killed 30 days after implantation. Histologic sections prepared from the skin specimens were stained with H&E, toluidine blue, Masson trichrome, and Congo red. The data were statistically analyzed with 1-way analysis of variance and paired t tests. The P value for significance was set at .05. RESULTS: After 7 days, MTA produced a significantly greater inflammatory reaction that involved the deposition of amyloidlike protein and an increase in the mast cell population compared with ERRM (P < .05). After 30 days, the ERRM group exhibited significantly reduced inflammatory reactions compared to the MTA groups (P < .05). Areas of mononuclear cell aggregation, abscess formation, and necrosis were observed more frequently in the MTA group. The thickness of the fibrous capsule was significantly increased in the MTA compared with the ERRM groups (P < .05). Amyloidlike proteins were more frequently observed around the fibrous capsule and subdermal blood vessels and were more frequently deposited in the MTA than the ERRM specimens. CONCLUSIONS: The findings of the present study suggest that both ERRM and MTA cause an injurious effect when implanted in rat subcutaneous tissues after 7 and 30 days. ERRM is significantly less injurious to tissues than MTA.

Enhancement of the ocular therapeutic effect of prednisolone acetate by liposomal entrapment.

Eye drops account for 90% of ophthalmic formulations despite of the rapid precorneal drug loss. Our aim is to test the effect of positive charge induction and the subsequent size reduction on the efficiency of liposomes as ocular drug delivery system for the lipophilic drug prednisolone acetate (PSA). Different formulations of PSA-loaded liposomes, positive multilamellar liposomes (pMLV), positive small (nano-sized) unilamellar liposomes (pSUV) and neutral multilamellar liposomes (nMLV), were prepared. These formulations were characterized by measuring surface charge, size distribution, entrapment efficiency, release rate, and ability to deliver PSA across the cornea. In vitro studies showed that positive charge induction reduces the transcorneal flux (about 1.9-fold lower than nMLV), while the subsequent size reduction results in higher flux (about 1.2-fold higher than nMLV). But in vivo results revealed that pSUV produced more concentrations of PSA in aqueous humor than nMLV (P < 0.05) suggesting greater chance for drug penetration, pSUV were more effective than nMLV in this regard (P < 0.05). As revealed by in vivo studies and ophthalmic examinations, positive charge induction and the subsequent size reduction increased the efficiency of liposomes as ocular drug delivery system for PSA.

Preparation and evaluation of warfarin-ß-cyclodextrin loaded chitosan nanoparticles for transdermal delivery.

The main objective of the present work was to prepare warfarin-ß-cyclodextrin (WAF-ß-CD) loaded chitosan (CS) nanoparticles for transdermal delivery. CS is a hydrophilic carrier therefore, to overcome the hydrophobic nature of WAF and allow its incorporation into CS nanoparticles, WAF was first complexed with ß-cyclodextrin (ß-CD). CS nanoparticles were prepared by ionotropic pre-gelation using tripolyphosphate (TPP). Morphology, size and structure characterization of nanoparticles were carried out using SEM, TEM and FTIR, respectively. Nanoparticles prepared with 3:1 CS:TPP weight ratio and 2mg/ml final CS concentration were found optimum. They possessed spherical particles (35±12nm diameter) with narrow size distribution (PDI=0.364) and 94% entrapment efficiency. The in vitro release as well as the ex vivo permeation profiles of WAF-ß-CD from the selected nanoparticle formulation were studied at different time intervals up to 8h. In vitro release of WAF-ß-CD from CS nanoparticles followed a Higuchi release profile whereas its ex vivo permeation (at pH 7.4) followed a zero order permeation profile. Results suggested that the developed WAF-ß-CD loaded CS carrier could offer a controlled and constant delivery of WAF transdermally.