Search

Magnesium-based bulk metallic glasses are attractive due to their single-phase, chemically homogeneous alloy system and the absence of second-phase, which could impair the mechanical properties and corrosion resistance. However, one of the unsolved problems for the manufacturability and the applications of bulk metallic glasses is that their glass-forming ability is very sensitive to the preparation techniques and impurity of components since oxygen in the environment would markedly deteriorate the glass-forming ability. Therefore, the aim of this study was to establish proper processing conditions to obtain a magnesium-based amorphous ternary alloy and its characterization. The final composition was prepared using two binary master alloys by melting in an induction furnace. Carbon steel crucible was used in argon atmosphere with and without addition of SF6 gas in order to minimize the oxygen contamination. The microstructure, amorphous nature, thermal properties and chemical analysis of samples were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and inductively coupled plasma emission spectrometry, respectively. The oxygen content of the as-cast samples was chemically analyzed by using carrier gas hot extraction (O/N Analyzer TC-436/LECO) and was kept bellow 25 ppm (without SF6) and 10 ppm (with SF6). Bulk samples were produced by rapid cooling in a cooper mold until 1.5 mm thickness, with amorphous structures being observed up to 2.5 mm.

Introduction: Recent simple dental extraction protocols suggest that therapeutic levels of the anticoagulant drug should be maintained because bleeding complications could be managed with local haemostasis manoeuvres. The aim of the present study was to evaluate the association between bleeding complications and the international normalized ratio (INR) values in patients after dental extractions completed with a plug of bismuth subgallate, without interrupting anticoagulant administration. Materials and Methods: Patients undergoing oral Vitamin K antagonist chronic anticoagulant therapy requiring simple dental extractions were included in the study. INRs were recorded on the day of the surgery, and dental extractions were performed applying bismuth subgallate as a haemostatic agent. Patients took their anticoagulation drug normally. Bleeding complications were recorded. Results: The study included 694 patients, of whom 11 (1.58%) presented mediate post-operative bleeding that was effectively controlled through local manoeuvres. No episode of thromboembolism or infectious endocarditis was observed. The incidence of bleeding complications was not related to the INR values (P > 0.05). Discussion: INR values were not related to bleeding complications when simple dental extractions were performed applying bismuth subgallate as a haemostatic agent. [ABSTRACT FROM AUTHOR]

Introduction: Oral anticoagulants are widely used worldwide for many systemic diseases. Recent oral surgical protocols suggest that therapeutic levels of the anticoagulant drug should be maintained for simple dental extractions because bleeding complications could be managed with proper local hemostasis. The aim of the present study was to compare bleeding complication of three different local hemostatic agents for dental extractions without interrupting drug administration in patients undergoing oral Vitamin K antagonist chronic anticoagulant therapy. Material and Methods: Randomized control trial of three hemostatic agents for dental extractions, in patients under oral anticoagulant therapy without drug interruption. The present study included 240 patients with international normalized ratio between 1.5 and 3.5. Patients took their anticoagulation drug normally. A single surgeon performed calibrated simple dental extractions and applied a plug of bismuth subgallate (BS), fibrin tissue adhesive (FTA) or microfibrillar collagen (MC), assigned randomly. Statistical analysis of bleeding between the groups was performed using the Chi-square test. Results: There was no hemorrhagic complication in the BS group, and only one in the FTA group. However, in the MC group, 10 patients (12.5%) suffered postoperative bleeding. Data analysis showed statistical differences between the MC group and the other two groups (P < 0.05). Discussion: BS and FTA showed similar clinical effectiveness and were more effective than MC for the control of postoperative bleeding in oral anticoagulated patients. [ABSTRACT FROM AUTHOR]

Background: To compare global surgical pain under nerve block and mandibular infiltration anesthesia techniques, and to evaluate pain during drilling and the distance to the mandibular canal in posterior mandible implant surgeries., Material and Methods: A prospective, randomized, controlled, double-blind, clinical trial was conducted to compare nerve block (Group A) to mandibular infiltration (Group B) techniques for dental implant placement. Global surgical pain (VAS = visual analogue scale), pain during drilling or implant placement (MPQ = McGill pain questionnaire) and distance to the mandibular canal (Image J) were statically analyzed. Age, gender, anxiety levels, tooth to be replaced, implant size, adjacent teeth and duration of surgery were also analyzed., Results: 172 patients were included and 283 dental implants were analyzed. VAS values were significantly higher in Group B ( p <0.05). In Group A, 99% of the surgeries were performed painlessly during drilling and implant placement, but in Group B, 11.6% of implant placements (17 implants) felt pain during these surgical steps. Mean distance to mandibular canal (3.8 mm, range: 0.0 to 7.0) in those 17 implants placed under mandibular infiltration was clinically and statistically similar to the mean distance (3.0 mm, range: 0.0 to 9.0) of 130 implants placed painless ( p =0.10). Pain during drilling under mandibular infiltration was significantly associated with the duration of surgery ( p <0.05) and to both adjacent teeth being present ( p <0.05)., Conclusions: Although both techniques are safe and effective for placing implants in the posterior mandible, nerve block provides a more profound analgesia than mandibular infiltration. When placing implants under mandibular infiltration, as getting closer to the canal does not increase the feeling of pain, it is not recommended to use the presence of pain as a preventive resource to avoid inferior alveolar nerve injuries. Key words: Dental implant, mandibular infiltration anesthesia, nerve block, pain, nerve injury., Competing Interests: Conflict of interest statement: All authors declare that they have no financial or personal relationships with other people or organizations that could inappropriately influence (bias) this work.