Background: With the increasing demands for adult orthodontics, a growing need arises to bond attachments to porcelain surfaces. Optimal adhesion to porcelain surface should allow orthodontic treatment without bond failure but not jeopardize porcelain integrity after debonding.The present study was carried out to compare the shear bond strength of metal bracket bonded to porcelain surface prepared by two mechanical treatments and by using different etching systems (Hydrofluoric acid 9% and acidulated phosphate fluoride 1.23%). Materials and Methods: The samples were comprised of 60 models (28mm *15mm*28mm) of metal fused to porcelain (feldspathic porcelain). They were divided as the following: group I (control): the porcelain surface left untreated and glazed, group II (Diamond bur group): the porcelain surface was treated with fine diamond bur at speed of 350000 rpm for 20 seconds, group III (Red stone bur): the porcelain surface was treated with coarse red stone bur at speed of 8500 rpm for 20 seconds. Each group consists of 20 samples, then each group subdivided into two subgroups; one treated with acidulated phosphate fluoride 1.23% and the other subgroup treated with Hydrofluoric acid 9 % with silane coupling agent. Results: The result of this study revealed that there was very high significant difference among all tested groups and the highest shear bond strength was for diamond bur group with HFA and Silane (8.67 MPa), the 2nd highest strength was for control group with HFA and Silane (7.52 MPa), the 3rd was (7.38 MPa) in red stone bur with HFA and Silane, the least shear bond strength values were obtained for subgroups treated with acidulated phosphate fluoride gel 1.23%. Conclusions: The most reliable procedure for bonding orthodontic brackets to the porcelain surfaces is through the surface treatment combinations of mechanical roughening by using diamond bur, 9% Hydrofluoric acid and Silane coupling agent application.
Diabetes mellitus is a multifaceted, chronic disease that happens either when the pancreas does not produce enough insulin or when the human body cannot competently use the insulin it produces. The study was aimed to determine and show the ultrastructural changes of cells in the placenta of women suffering from diabetes mellitus disease. In this study, a total of 102 placentas were investigated by transmission electron microscopy, which includes 34 placentas with gestational diabetes, 34 placentas with pregestational diabetes, and 34 placentas with normal pregnancy as a control group. Placental vascular-syncytial membrane, trophoblastic basement membrane, villous stroma, and fetal vessel were investigated for their thickening basement membr
... Show MoreBackground: Poly (methyl methacrylate) has several disadvantages (poor mechanical properties) like impact and transverse strength. In order to overcome these disadvantages, several methods were used to strengthen the acrylic resin by using different fibers or fillers. This study was conducted to evaluate the effect of Plasma treatment of the fiber on mechanical properties Poly (methyl methacrylate) denture base material. Materials and methods: Specimens were prepared from poly methyl metha acrylic (PMMA) divided according to present of fiber into 4 groups (first group without fiber as control group, second group with Plasma treated polyester fibers, third group with Plasma treated polyamide fibers and fourth group Plasma treated combination
... Show MoreA simple, accurate and sensitive spectrophotometric way is used to determine Bisacodyl in pure and pharmaceutical preparations. The proposed method depends on using 2,4-Dinitrophenylhydrazine as chromogenic reagent . The method was based on the oxidative coupling reaction of Bisacodyl with 2,4-Dinitrophenylhydrazine with Sodium periodate in the presence of sodium hydroxide as alkaline media to form red water soluble dye product , that has a maximum absorption at ?max 522nm . Beer ,s law is obeyed in the concentration of (2.00–20.00) ?g.ml -1 .The molar absorptivity is (6505) L.mol-1.cm-1,a sandall sensitivity of(0.0555) ?g.cm-2), correlation coefficient of (0.9970) , Limitof detection (LOD) (0.0312 ?g.ml-1), limit of Quantitation (LOQ) (
... Show MoreTo investigate the antiplaque and antigingivitis efficacy in addition to evaluating side effects and subjects’ perceptions of three commercially available mouthwashes.
This study was a double‐blind, parallel, and short‐term trial. A total of 75 dental students with biofilm‐induced gingivitis were included in the final analysis of the current study. Clinical parameters (plaque index and bleeding on probing) and the staining effect were measured at baseline and after 7 days. In addition, a VAS‐based assessment questionnaire was completed by the participants.
Background: Green Tea is made from the leaf of the plant “Camellia sinensisâ€. Green tea is reported to contain thousands of bioactive ingredients including catechins which have shown great promise for having antimicrobial effects. Periodontal diseases represent one of the most prevalent diseases around the world and the main etiologic factor behind it, is plaque accumulation, in addition certain kinds of bacteria have been detected frequently in subjects suffering from periodontitis, Several studies suggested that the outcome of periodontal treatment is better if particular pathogens including Aggregatibacteractinomycetemcomitans can no longer be detected after therapy. Materials and Methods: plaque samples were collected from 2
... Show MoreOxidative stress is oxidative damage caused by free radicals and reactive oxygen species (ROS). These ROS can cause oxidative damage to cellular components, including membrane lipids, receptors, enzymes, proteins, and nucleic acids. It would eventually lead to cell apoptosis and the appearance of certain pathological conditions. This work investigates the antioxidant potentials of chamomile extract in vitro by evaluating the extract activity to scavenge 2,2-Diphenyl-1-picrylhydrazyl (DPPH), also in vivo by investigating its effects on oxidative stress-induced rats by assessing the total oxidant status (TOS) and total antioxidant capacity in the radiation exposed rats with and without the treatment with chamomile extract. The results
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