Vertical Root Fracture in Upper Premolars with Endodontic Posts: Finite Element Analysis

Upper premolars restored with endodontic posts present a high incidence of vertical root fracture (VRF). Two hypotheses were tested: (1) the smaller mesiodistal diameter favors stress concentration in the root and (2) the lack of an effective bonding between root and post increases the risk of VRF. Using finite element analysis, maximum principal stress was analyzed in 3-dimensional intact upper second premolar models. From the intact models, new models were built including endodontic posts of different elastic modulus (E = 37 or E = 200 GPa) with circular or oval cross-section, either bonded or nonbonded to circular or oval cross-section root canals. The first hypothesis was partially confirmed because the conditions involving nonbonded, low-modulus posts showed lower tensile stress for oval canals compared to circular canals. Tensile stress peaks for the nonbonded models were approximately three times higher than for the bonded or intact models, therefore confirming the second hypothesis.     

Caudal septoplasty: efficacy of a surgical technique-preliminnary report

Although not being the most frequent nasal septal deviations, those of the caudal septum account for many complaints. The correction of such defects has always been the subject of much controversy, and several different operative techniques have been described.AimTo assess the efficacy of a surgical technique for correcting caudal septal deviations.Materials and MethodsProspective study with preliminary reports of 10 patients who answered a standardized, specific questionnaire (the Nasal Obstruction Symptom Evaluation, or NOSE), underwent acoustic rhinometry and had their noses photographed. Caudal deviations were then corrected through a surgical technique whereby the entire deviated portion is removed and a straight cartilage segment is placed between the medial crura of the alar cartilages, through a retrograde approach, to support the nasal tip. Sixty days after all patients were reassessed.ResultsAs for the NOSE questionnaire, mean pre-operative and post-operative scores were 82.39 and 7.39 respectively (p<0.001). Pre-operative acoustic rhinometry showed mean minimum crosssectional area (MCA) values of 0.352 and 0.431 cm2, whereas mean post-operative values were 0.657 and 0.711 cm2(p<0.0001).ConclusionsThe study results prove, both subjectively (patient satisfaction as measured with a standardized questionnaire) and objectively (acoustic rhinometry findings), that the proposed technique for correction of caudal septal deviation is safe and effective.     

Strength of Denture Base Resins Repaired with Auto- and Visible Light-Polymerized Materials

Purpose: Clinicians are still confused about the choice of repair method, which depends on factors such as the length of time required for processing, the mechanical strength of the repaired material, and the effect of stress concentration in the acrylic resins before the repair. The aim was to determine the impact and flexural strength characteristics, such as stress at yield, Young's modulus, and displacement at yield of denture base resins fractured and repaired by three methods using heat‐, auto‐, and visible light‐polymerized acrylic resins. Material and Methods: For impact and flexural strength tests, 18 rectangular specimens measuring 50 × 6 × 4 mm³ and 64 × 10 × 3.3 mm³, respectively, were processed using Impact 2000, Lucitone 550, Impact 1500, and QC‐20 acrylic resins. Fracture tests were performed according to ISO1567:1999. Afterward, all fractured specimens were stored in distilled water at 37°C for 7 days, and then repaired with (1) the same acrylic resin used for specimen fabrication (n = 6), (2) an autopolymerized acrylic resin (TruRepair, n = 6), and (3) a visible light acrylic resin (Versyo.com, n = 6). The repaired specimens were again submitted to the same fracture tests, and the failures were classified as adhesive or cohesive. Data from all mechanical tests after repair by the different methods were submitted to two‐way ANOVA, and mean values were compared by the Tukey test. Results: All acrylic resins showed adhesive fractures after impact and flexural strength tests. Differences (p < 0.05) were found among repair methods for all acrylic resins studied, with the exception of displacement at yield, which showed similar values for repairs with auto‐ and visible light‐polymerized acrylic resins. The highest values for impact strength, stress, and displacement at yield were obtained when the repair was made with the same resin the specimen was made of. Conclusion: Denture base acrylic resins repaired with the same resin they were made of showed greater fracture strength.     

Olanzapine Solvates

Olanzapine was crystallized from 12 organic solvents alone or in mixture, by cooling in the freezer, by slow evaporation of the solvent, or by suspending olanzapine powder for some time in the solvent. All the samples thus obtained were examined by thermal analysis (differential scanning calorimetry—DSC and thermogravimetry—TG) to certify the formation of a solvate, the presence of polymorph (form 1 or 2) in the desolvated olanzapine, comparing the different profile of the thermograms, and to calculate the stoichiometry of the possible solvate. According to the DSC thermogram, the solvents can be divided into four classes: those that do not form solvates and leave olanzapine form 1 (ethyl acetate, toluene, diethyl ether, and acetone); those that form solvate and leave form 1 of olanzapine after desolvation (methanol, 1- and 2-propanol); those that after desolvation of the solvate show a polymorph transition in the thermogram indicating the presence of form 2 of olanzapine (ethanol); other solvents (tetrahydrofuran, chloroform, acetonitrile) give solvate thermograms, where this last thermal trace is only poorly evident. With few exceptions, each solvent forms solvate both when pure and in mixture (10%, v/v, in ethyl acetate). Methanol monosolvate displays complex thermogram and thermogravimetric desolvation profiles, depending on the crystallization experimental conditions, used to prepare the solvates. Dichloromethane solvate was found by X-ray diffraction analysis to be amorphous and, on heating during DSC analysis, allowed the crystallization of both form 1 and 2, with different weight ratio, according to the experimental conditions of the solvate preparation.     

Excess weight and associated risk factors in patients with systemic lupus erythematosus

The objective of this study is to determine the socio-demographic, clinical and laboratory characteristics of outpatients with SLE who present with excess weight as well as to assess the immunosuppressive therapy used. One hundred and seventy women with SLE were evaluated consecutively in a transversal study. The relationship between excess weight and the patients’ characteristics was evaluated using univariate and multivariate Poisson regression analysis. Of the 170 patients evaluated, 109 presented with excess weight, two were malnourished and 59 were classified as eutrophic. Age and disease duration of those with excess weight were 42.4 ± 8.7 and 10.4 ± 6.2 years, respectively. Risk factors associated with excess weight were the following: age ≥40 years, <8 years of education, lack of occupation, damage index ≥1, systemic high blood pressure, diabetes mellitus and triglycerides ≥150 mg/dL levels. The use of antimalarial therapy and steroids was associated with a lower frequency of excess weight. Age ≥40 years and the non-usage of methotrexate were the variables independently associated with excess weight in the multivariate analysis. Patients with SLE who have excess weight present distinct clinical-laboratory findings, socio-demographic characteristics and treatment options when compared to normal weight patients. Prospective studies should assess whether these characteristics will interfere with the outcome or prognosis of lupus.     

3-Phenylcoumarin derivatives selectively modulate different steps of reactive oxygen species production by immune complex-stimulated human neutrophils

Immune complex (IC) deposition in tissues triggers the release of harmful oxidant and lytic compounds by neutrophils. We examined how ten 3-phenylcoumarin derivatives affect the reactive oxygen species (ROS) production by IC-stimulated human neutrophils. Most of the 3-phenylcoumarins inhibited the luminol-enhanced chemiluminescence (CL-lum) more strongly than they inhibited the lucigenin-enhanced chemiluminescence (CL-luc), without clear signs of toxicity. The most effective CL-lum inhibitors, 6,7-dihydroxy-3-[3′,4′-methylenedioxyphenyl]-coumarin (5) and 6,7-dihydroxy-3-[3′,4′-dihydroxyphenyl]-coumarin (19), also inhibited myeloperoxidase activity more potently and had higher hypochlorous acid scavenging ability, but did not affect the NADPH-oxidase activity. The type, number, and position of the substituent influenced the pharmacological effects of 3-phenylcoumarins; however, the structural requirements for CL-lum and CL-luc inhibition were a little different. Compounds 5 and 19 are promising prototypes of therapeutic molecules to modulate ROS production by neutrophils in IC-mediated inflammatory diseases.