Effects of ultrasonic and sonic scaling on surfaces of tooth‑colored restorative materials: An in vitro study

Objective: The effects of sonic and ultrasonic scalings (USSs) on the surface roughness of nanohybrid, flowable, and polyacid-modified resin composites and conventional glass ionomer cement were examined, and the effectiveness of repolishing on the scaled material surfaces was determined.Materials and Methods: The surface roughness of each sample was measured three times before and after each scaling and after repolishing, and the data were analyzed using repeated measuresanalysis of variance, Tukey’s multiple comparisons, and paired t-tests by a statistical program.Results: Although sonic and USS both significantly increased the surface roughness of all the tooth-colored materials, USS roughened the surfaces of all the test materials more than SS did. Hence, USS may detrimentally affect tooth-colored restorative materials, especially conventional glass ionomers and compomers. Repolishing decreased the surface roughness of all the materials to near their baseline levels.Conclusions: On the basis of these results, the repolishing of restoration surfaces is strongly recommended after dental scalings.Keywords: Repolishing, sonic scaling, tooth‑colored dental materials, ultrasonic scalin

Redox homeostasis of albumin in relation to alpha-lipoic acid and dihydrolipoic acid

Albumin represents the predominant circulating antioxidant agent in plasma exposed to continuous oxidative stress and a change in serum albumin structure accounts for its antioxidant properties. Alterations in the redox status of albumin may result in impairments of its biological properties. Alpha-lipoic acid (LA), a naturally occurring thiol compound found in virtually all species, is a potent antioxidant with high efficacy which is also involved in the chelation of metal ions, regeneration of antioxidants, and repair of oxidatively damaged proteins. In human body LA is rapidly reduced to dihydrolipoic acid (DHLA) after intake into the cell. Both, LA and DHLA are amphipathic molecules which act as antioxidants both in hydrophilic and lipophilic environments. The present study aimed to investigate the antioxidant/pro-oxidant effects of LA and DHLA due to their concentrations in metal-catalyzed protein oxidation (MCO) of human serum albumin (HSA). Progressive oxidative modification of albumin was found in MCO system by an increased content of protein hydroperoxides (POOH), protein carbonyl groups (PCO) which is the former's major breakdown product, and other protein oxidation markers such as advanced oxidized protein products (AOPP) and protein thiol groups (P-SH). The possible antioxidant protective effects of LA and DHLA were observed with 25 µM and 50 µM; DHLA being more influential. Protein oxidation parameters were found to be lower and P-SH levels seemed higher. However, prooxidant effects of both LA and DHLA came on the scene with increased concentrations of 75 µM and 100 µM where the latter seemed the most hazardous with contradicted results. It is clear that the loss of biological activity of human serum albumin by MCO system appears of medical relevance and if LA exerts similar effects seen in the present study, it is possible that cellular prooxidant activity can also result consuming this unique antioxidant in certain doses

Label-Free Electrochemical Detection of the Specific Oligonucleotide Sequence of Dengue Virus Type 1 on Pencil Graphite Electrodes

A biosensor that relies on the adsorption immobilization of the 18-mer single-stranded nucleic acid related to dengue virus gene 1 on activated pencil graphite was developed. Hybridization between the probe and its complementary oligonucleotides (the target) was investigated by monitoring guanine oxidation by differential pulse voltammetry (DPV). The pencil graphite electrode was made of ordinary pencil lead (type 4B). The polished surface of the working electrode was activated by applying a potential of 1.8 V for 5 min. Afterward, the dengue oligonucleotides probe was immobilized on the activated electrode by applying 0.5 V to the electrode in 0.5 M acetate buffer (pH 5.0) for 5 min. The hybridization process was carried out by incubating at the annealing temperature of the oligonucleotides. A time of five minutes and concentration of 1 μM were found to be the optimal conditions for probe immobilization. The electrochemical detection of annealing between the DNA probe (TS-1P) immobilized on the modified electrode, and the target (TS-1T) was achieved. The target could be quantified in a range from 1 to 40 nM with good linearity and a detection limit of 0.92 nM. The specificity of the electrochemical biosensor was tested using non-complementary sequences of dengue virus 2 and 3

Use of a New Ziprasidone-Selective Electrode in Mixed Solvents and Its Application in the Analysis of Pharmaceuticals and Biological Fluids

The construction and characterization of a new ion-selective electrode for the determination of the antipsychotic ziprasidone in mixed solvents is presented. The electrode contains a plasticized polymeric membrane based on a ziprasidone-tetraphenylborate ion-exchanger. The influence of membrane composition on the electrode response towards ziprasidone in hydroalcoholic solutions was studied. The electrode displayed a stable response in a 2:3 (v/v) methanol/water medium from a ziprasidone concentration of 3 × 10−6 M with a fast response time of less than 20 s. The electrode also showed good selectivity towards ziprasidone over common inorganic and organic compounds and several species with pharmacological activity. The electrode was successfully applied to the determination of ziprasidone in pharmaceuticals and human urine and serum

ACTA ORTHOPAEDICA ET TRAUMATOLOGICA TURCICA

Objective: The aim of this study was to biomechanically compare 3 different cannulated screw configurations used in internal fixation of unstable femoral neck fractures. Methods: The study included 28 synthetic left femurs randomly divided into 4 equal groups. Samples in the first 3 groups were osteotomized in the basicervical region to create Pauwels Type 3 fractures. Fixation was carried out using cannulated screws. In Group 1, four screws were used including 3 in an inverted triangle configuration in parallel with the neck and the fourth screw transversely into the calcar. In Group 2, three screws were used including 2 in parallel with the neck and the third transversely into the calcar. In Group 3, three screws were used in an inverted triangle configuration in parallel with the neck. No osteotomy or fixation was carried out in Group 4. Load test was performed on all the groups and the strength of the screw fixations against axial load and their amount of relocation were measured. Results: Average maximum strength was 36.1 +/- 3.2 N/mm(2) in Group 1, 27.3 +/- 4.1 N/mm(2) in Group 2 and 21.9 +/- 3.2 N/mm(2) in Group 3. The average relocation in the line of osteotomy in the moment of average maximum stress (21.9 +/- 3.2 N/mm(2)) was 11.5 +/- 2.1 mm in Group 3,6 +/- 1.3 mm in Group 2 and 5.8 +/- 1.1 mm in Group 1 (p0.05). Conclusion: The use of a transverse screw in the calcar in addition to cannulated screws parallel to the neck appear to provide stability benefit in the treatment of unstable femoral neck fractures