Background: This study was conducted to assess the effect of sonic activation and bulk placement of resin composite in comparison to horizontal incremental placement on the fracture resistance of weakened premolar teeth. Materials and method: Sixty sound human single-rooted maxillary premolars extracted for orthodontic purposes were used in this study. Teeth were divided into six groups of ten teeth each: Group 1 (sound unprepared teeth as a control group), Group 2 (teeth prepared with MOD cavity and left unrestored), Group 3 (restored with SonicFill™ composite), Group 4 (restored with Quixfil™ composite), Group 5 (restored with Tertic EvoCeram® Bulk Fill composite) and Group 6 (restored with Universal Tetric EvoCeram® composite using horizontal incremental layering technique). Standardized class II MOD cavity was prepared in all teeth except (group 1).After finishing the restorative procedure of each group according to the manufacturer's instructions, all teeth were stored in deionized distilled water in an incubator at 37°C for seven days.All specimens were subjected to compressive axial loading until fracturein a universal testingmachine.Specimens were examined by a stereomicroscope at a magnification of (20X) to evaluate the mode of fracture . Results: The results of this study revealed that the control group exhibited the highest fracture resistance compared to all prepared teeth groups (restored or unrestored) and the differences were statistically highly significant (P<0.01), except with group 3 (which was restored with SonicFill™ composite) where the difference was statistically significant only (P < 0.05).Additionally the results of this study revealed that the prepared unrestored teeth (Group 2) exhibited the lowest fracture resistance compared to all restored groups and the differences were statistically highly significant (P<0.01). Meanwhile, among the restored teeth groups, teeth restored with SonicFill™ composite (group 3) exhibited the highest fracture resistance as compared with all other restored groups and the difference was statistically highly significant (P<0.01). On the other hand, no statistically significant differences in fracture resistance were found among groups 4, 5 and 6, which were restored with Quixfil™ composite, Tetric EvoCeram® Bulk Fill composite and Universal Tetric EvoCeram® composite, respectively (P > 0.05). Group 3and Group 5 showed mostly mixed mode of failure, while Group 4 showed mostly adhesive mode of failure. On the other hand Group 6 teeth showed different modes of failure. Conclusions: SonicFill™ composite can be considered as a viable treatment modality for the restoration of weakened maxillary premolar teeth. On the other hand, the time-consuming incremental layering technique can be substituted with bulk filling, using bulk fill materials (Quixfil™ and Tetric EvoCeram® Bulk Fill) for reinforcement ofweakened maxillary premolars.
Nutrient agar medium with various concentrations of cefotaxime was used for isolation spontaneous mutants from wild type strain of P.aeruginosa PHA-1. Eighty-two mutants were successfully isolated with the viable count 52×107 , these mutants were confirmed as spontaneous not physiological adaption mutants by reculture on the same medium. Then, wild type PHA-1 and mutants were examined for production pyocyanin; a blue greenish pigment was clearly noticed on King A medium. Remarkably the mutant strain named S300-8 was distinguished in productivity in comparison with wild type strain PHA-1; the amount of pigment was 56.0667mg/l and 74.53mg/l respectively. In addition, pyocyanin produced by mutant strain S300-8 revealed a potent efficacy again
... Show MorePolyacrylonitrile nanofiber (PANFS), a well-known polymers, has been extensively employed in the manufacturing of carbon nanofibers (CNFS), which have recently gained substantial attention due to their excellent features, such as spinnability, environmental friendliness, and commercial feasibility. Because of their high carbon yield and versatility in tailoring the final CNFS structure, In addition to the simple formation of ladder structures through nitrile polymerization to yield stable products, CNFS and PAN have been the focus of extensive research as potential production precursors. For instance, the development of biomedical and high-performance composites has now become achievable. PAN homopolymer or PAN-based precursor copolymer can
... Show MoreBackground: The clinical examination is one of the best suitable methods for diagnosis of low backache. Backache is one disease that the signs, clinical examination finding, and the results on imaging modalities not always related. The straight leg raising (SLR) and slump tests, can be used for diagnosis of lumber disc herniation. Objectives: To compare the result of the slump test and SLR test in the diagnosis of lumber disc herniation. Subjects and Methods: A prospective comparative study conducts on 280 patients in Al-Kindy teaching and private clinics complaints of backache, aging between 18-70 years old with acute or recurrent backache, sciatica pain, or low back and sciatica pain for last 12 weeks, while patients
... Show MoreBackground: The clinical examination is one of the best suitable methods for diagnosis of low backache. Backache is one disease that the signs, clinical examination finding, and the results on imaging modalities not always related. The straight leg raising (SLR) and slump tests, can be used for diagnosis of lumber disc herniation.
Objectives: To compare the result of the slump test and SLR test in the diagnosis of lumber disc herniation.
Subjects and Methods: A prospective comparative study conducts on 280 patients in Al-Kindy teaching and private clinics complaints of backache, aging between 18-70 years old with acute or recurrent backache, sciatica pai
... Show MoreThe technique of plant tissue culture has been used to In vitro micropropagation of Spilanthes acmella (L.) Murr. It is an ornamental and medicinal plant not cultivated in Iraq. Seeds were sterilized and cultuared on full strength Murashige and Skoog medium(1962)(MS). Naphthalene acetic acid (NAA), 6- furfuryl aminopurine (Kin.) growth regulators were used at the Initiation stage.The combination between IAA and Kin. was used in multiplication stage. IAA was used for rooting the shoots. Results showed that 1.5% sodium hypochlorite for 15 min was very effective for disinfecting and survival. Nodes exhibited relatively highest response as compared with apical meristems and leaflets culture. Supplying the culture medium with 1 mg/L.
... Show MoreCompaction of triticale grain with three moisture contents (8%, 12%, and 16% wet basis) was measured at five applied pressures (0, 7, 14, 34, and 55 kPa). Bulk density increased with increasing pressure for all moisture contents and was significantly (p < 0.0001) dependent on both moisture content and applied pressure. A Verhulst logistic equation was found to model the changes in bulk density of triticale grain with R2 of 0.986. The model showed similar beha