1,721,027 research outputs found
Mechanical evaluation of new injection needles for dental anesthesia
No full textAIM: In this study Authors want to evaluate the static and dynamic flexural behaviour of innovative injection needles for dental anaesthesia comparing to the traditional needles. METHODS: Four kinds of innovative injection needles (Carpule Free Flow-Heraeus Kulzer), different for length and external diameter, have been evaluated in comparison with the traditional ones (Carpule-Heraeus Kulzer), dimensions being equal except for the internal diameter. Static stiffness tests (10 for each kind of needles, resulting in a totality of 80 tests) and fatigue bending test (10 for each kind of needles, each tested at 3 different bending angles, resulting in a totality of 240 tests) have been conducted following the ISO 9626 norms. The final comparison among the obtained data have been conducted using a one way statistical analysis of variance (ANOVA). RESULTS: After stiffness tests the Carpule Free Flow injection needles and the traditional ones showed the same static behaviour, resulting in statistical comparable values of mean deflection at the maximum load allowed by ISO norms tests, whereas the 0.4 mm external diameter showed a statistically significant difference because the Carpule Free Flow needles achieved lower deflection values. After dynamic bending tests at 20 degrees both needle types showed the same behaviour, whereas at 30 degrees bending the Carpule Free Flow injection needles showed a higher number of breaks comparing to normal type, up to a maximum value of breaks (10 out of 10) for the 0.4 mm external diameter needles. After 50 degrees fatigue bending tests the Carpule Free Flow needles came to the break point after lower number of cycles than the Carpule needles. CONCLUSION: This study pointed out that, among anaesthesia injection needles, the Carpule Free Flow needles not only showed better clinical characteristics but also a mechanical behaviour, both static and dynamic, statistically similar to traditional ones, according to international standards. After fatigue bending higher than 20 degrees, exclusively made in this research in order to simulate critical or extreme conditions, all analysed Carpule Free Flow needles have been broken after a lower number of cycles. It is concluded that it is recommended not to repeatedly bend this kind of needles at more than 90 degrees. At the end of this study it may be suggested that this kind of needles cannot be repeatedly bended at angles more than 90 degrees
Long-term treatment with low doses of interleukin-2 and interferon-alpha: immunological effects in advanced renal cell cancer
No full textEffects of Nd: Yag laser on dental enamel.
No full textCaries prevention should be an important goal of the dentistry practitioner. In addition to traditional preventive techniques, laser beam has been a recent suggestion. This study aimed to evaluate Nd:YAG laser treatment effects on dental enamel surfaces, irradiated at different energy levels, by scanning electron microscopy (SEM) observations and surface micro-hardness tests to evaluate if caries prevention can be achieved by laser treatment. Forty human teeth were divided in four groups of 10 specimens each: in three groups the enamel surface was treated with three different laser beam energy levels, 60, 120 and 160 mJ, in one group the enamel was not lased. Five samples from each group were subjected to the Vickers microhardness test and five samples underwent SEM investigation. Results of the microhardness test demonstrated no significant differences between treated and non-treated dental enamel samples. SEM observation demonstrated a rougher enamel surface in all treated groups: the 60 mJ treated group showed tooth surfaces with vertical scratches, the 120 mJ treated group showed the enamel surface covered by craters and cracks, and the 160 mJ treated group showed a completely changed enamel structure with columns separated by voids and with a glass-like surface. These investigations demonstrated that dental enamel laser treatment at low energy levels (not >60 mJ) produces a protective glass-like surface, without the loss of its integrity and could be an advisable technique to prevent caries. Higher energy laser treatment leads to modifications of the enamel morphology such as craters and cracks, even if it does not cause any change in enamel hardness characteristics, which could be more useful in conservative dentistry
Raccolta dell’espirato condensato con un semplice sistema che ne aumenta la quantità e ne previene la contaminazione salivare.
No full textEarly fatal hemoptysis after first-dose, first-line pembrolizumab in a central lung cancer: Did tumor shrinkage matter?
No full textA patient diagnosed with centrally located advanced lung adenocarcinoma with signs of large vessels infiltration, strongly expressing PD-L1, was candidate to first-line pembrolizumab. He had not complained of any bleeding manifestation before immunotherapy. 5 days after the first dose of pembrolizumab, the patient experienced massive, fatal hemoptysis. Given the central localization of the tumor and the strong PD-L1 expression, a contribution of rapid disease shrinkage is envisaged in determining the fatal hemorrhagic event. An attentive clinical attitude should be dedicated in centrally located and vessel-infiltrating tumors strongly expressing PD-L1 and candidate to anti-PD-1/PD-L1 agents
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