IN VITRO EVALUATION OF THE PRECISION OF WORKING CASTS FOR IMPLANT-SUPPORTED RESTORATION WITH MULTIPLE ABUTMENTS

Objective:

The purpose of this study was to compare the accuracy of two working cast fabrication techniques using strain- gauge analysis.

Methods:

Two working cast fabrication methods were evaluated. Based on a master model, 20 working casts were fabricated by means of an indirect impression technique using polyether after splinting the square transfer copings with acrylic resin. Specimens were assigned to 2 groups (n=10): Group A (GA): type IV dental stone was poured around the abutment analogs in the conventional way; Group B (GB), the dental stone was poured in two stages. Spacers were used over the abutment analogs (rubber tubes) and type IV dental stone was poured around the abutment analogs in the conventional way. After the stone had hardened completely, the spacers were removed and more stone was inserted in the spaces created. Six strain-gauges (Excel Ltd.), positioned in a cast bar, which was dimensionally accurate (perfect fit) to the master model, recorded the microstrains generated by each specimen. Data were analyzed statistically by the variance analysis (ANOVA) and Tukey''s test (α= 5%).

Results:

The microstrain values (με) were (mean±SD): GA: 263.7±109.07με, and GB: 193.73±78.83με.

Conclusion:

There was no statistical difference between the two methods studied.     

Shear bond strength between metal alloy and a ceramic system, submitted to different thermocycling immersion times

The aim of this study was to evaluate the shear bond strength of Co-Cr and Ni-Cr metal alloys and a specific ceramic, submitted to different thermocycling immersion times. Sixty metal-ceramic specimens were confectioned and standardized in cylindricalformat. Three thermocycling conditions were evaluated: without thermocycling, 3,000 cycles (5 degrees C/55 degrees C+/-1) with 30s of immersion time and 3,000 cycles (5 degrees C/55 degrees C+/-1) with 60s. The shear bond strength was performed in a universal testing machine, using a special device to concentrate the tension at the metal/ceramic interface during the test. The load was applied until fracture of the specimens. The data was statistically analyzed by ANOVA (two-way) and Tukey (p<0.05) test. The results didn't show significant statistic differences between the metal-porcelain combinations. Nevertheless, both metal-ceramic systems submitted to 60s of immersion time showed lower values compared to specimens without thermocycling. It was concluded that the thermocycling immersion time of 1 minute affect the shear bond strength values for the Ni-Cr/porcelain and Cr-Co/porcelain systems.     

Outcomes of transoral laser microsurgery and transoral robotic surgery in oropharyngeal squamous cell carcinoma

ObjectiveTransoral robotic surgery (TORS) has evolved to a standard therapy modality for oropharyngeal carcinoma, especially in T1/ T2 tumors involving the base of the tongue due to its advantages compared with open surgery. However, knowledge about its benefits compared with transoral laser microsurgery (TLM) are scarce. This study compares oncological and functional results of TLM or TORS in the treatment of oropharyngeal squamous cell carcinoma (OPSCC).MethodsThis retrospective analysis comprises all patients with OPSCC treated with TLM (n = 30) or TORS (n = 24) between April 2003 and May 2018 (follow-up 43 ± 38.3 months). Both treatment groups (TLM and TORS) were comparable in terms of the stage of the disease, prognosis-determining factors, and adjuvant therapy modalities.ResultsThere were no significant differences regarding to the resection status (p = 0.272), the rate of local- (p = 0.834) and distant- recurrence (p = 0.416), with a disease-free survival of 86.7 % and 87.5 %, respectively (p = 0.892). In addition, we could not confirm any differences regarding to operating time (p = 0.860), intraoperative blood loss (p = 0.660), inpatient stay (p = 0.585) and postoperative bleeding rate (p = 0.245). The frequency of tracheostomy and percutaneous endoscopic gastrostomy between both groups is comparable, with a longer duration of tube feeding in patients who have received TLM (p = 0.030).ConclusionIn conclusion, TORS allows for similar oncological outcomes compared with TLM at comparable perioperative risks. The postoperative swallowing function may benefit from TORS.     

Intensified CHOP regimen in aggressive lymphomas: maximal dose intensity and dose density of doxorubicin and cyclophosphamide.

BACKGROUND: Following our previous study of CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) intensification in non-Hodgkin's lymphoma (NHL), in the present report we attempted to further increase dose intensity by shortening the between-course intervals with the support of growth factors. PATIENTS AND METHODS: A total of 67 patients were enrolled. With a fixed dose of doxorubicin 75 mg/m(2), cyclophosphamide (CTX) was started at a dose of 1750 mg/m(2) and increased by 250 mg/m(2) in consecutive cohorts of patients provided that no dose-limiting toxicity occurred. After the maximal tolerated dose (MTD) had been identified, this was used to treat more patients in order to confirm the feasibility of the regimen on a large scale, with the number of cycles being varied on the basis of disease extension. RESULTS: Twenty-three cases were enrolled in the CTX dose finding phase. Dose-limiting non-hematological toxicity occurred at 2250 mg/m(2). As the intermediate level of 2000 mg/m(2) had a borderline toxicity profile, a CTX dose of 1750 mg/m(2) was defined as the MTD. A total of 53 patients then received the MTD during the course of the study as a whole. At the MTD, toxicity was acceptable. Only 10 of 189 cycles (4%) required hospitalization due to infection or febrile neutropenia. Seventy-four percent of the patients achieved complete remission. Freedom from progression and overall survival at 12 months were 71% and 86% in the whole series, and 58% and 71% for high-risk cases, respectively. CONCLUSIONS: This intensified CHOP regimen is feasible on an outpatient basis. It can be safely considered a definitive treatment in patients at low and intermediate risk, and as induction before high-dose consolidation in high-risk cases.     

Molecular typing of Agrobacterium species isolates from catheter-related bloodstream infections.

Agrobacterium isolates from intravenous catheters of three hospitalized patients were initially identified as A. tumefaciens, but inability to produce 3-ketolactose revealed that two of them were A. vitis. However, rDNA analysis correlated all of the isolates to A. tumefaciens. Pulsed-field gel electrophoresis analysis ascertained the nosocomial transmission of the infection.     

A pilot study of low-dose subcutaneous alemtuzumab therapy for patients with hemotherapy-refractory chronic lymphocytic leukemia

Subcutaneous low-dose alemtuzumab (10 mg t.i.w. for 18 weeks) induced a 50% response rate, including 25% complete response, in 16 patients with refractory chronic lymphocytic leukemia (CLL) patients. The responses were substantial even in patients with unfavorable cytogenetics, fludarabine/rituximab refractoriness, Rai stage IV, previous infections, and age over 65 years. Subcutaneous low-dose alemtuzumab is effective in poor prognosis B-CLL, and has a particularly favourable toxicity profile.     

Abnormal uterine bleeding associated with hormonal contraception

Millions of women in the United States use some type of hormonal contraception: combination oral contraceptive pills (OCPs), progestin-only pills, medroxyprogesterone acetate injections, or subdermal levonorgestrel implants. Abnormal uterine bleeding is a common but rarely dangerous side effect of hormonal contraception. It is, however, a major cause for the discontinuation of hormonal contraception and the resultant occurrence of unplanned pregnancy. The evaluation of abnormal uterine bleeding in women who are using hormonal contraception includes an assessment of compliance, a thorough history and complete physical examination to exclude organic causes of bleeding, and a targeted laboratory evaluation. Pregnancy and the misuse of OCPs are frequent causes of abnormal uterine bleeding. Bleeding is common during the first three months of OCP use; counseling and reassurance are adequate during this time period. If bleeding persists beyond three months, it can be treated with supplemental estrogen and/or a nonsteroidal anti-inflammatory drug (NSAID). Other options are to change to an OCP with a higher estrogen content or to a different formulation (i.e., a low-dose OCP containing a different progestin). Management strategies for women with abnormal uterine bleeding who are using progestin-only contraceptive methods include counseling and reassurance, as well as the administration of supplemental estrogen and/or an NSAID during bleeding episodes.     

Unsuspected skeletal sarcoidosis mimicking metastatic disease on FDG positron emission tomography and bone scintigraphy

Sarcoidosis is a disease process of unknown cause that exhibits heterogeneous clinical manifestations. Although the mediastinum and lungs are most commonly involved, the granulomatous process may also affect the skeleton, skin, eyes, kidneys, spleen, and liver. A 51-year-old woman with low back pain and no history of cancer was found to have a suspicious lesion at L4 on magnetic resonance imaging. Findings of bone scintigraphy were consistent with multiple metastases, and computed tomography of the chest identified two small indeterminate pulmonary nodules. Similarly, findings of fluorodeoxyglucose positron emission tomography were consistent with widespread skeletal metastases, but a primary tumor was not identified. Biopsy of a left femur lesion was diagnostic of active sarcoidosis with no evidence of cancer.     

Anticoagulation for Mechanical Heart Valves in Patients with and without Atrial Fibrillation

Surgical replacement of a native valve with a biological or mechanical prosthesis is the definitive treatment for many forms of advanced valvular heart disease. Mechanical heart valves are less prone to structural deterioration compared with bioprostheses, but require chronic oral anticoagulation to prevent thromboembolic events. Thromboembolic risk varies based on patient-related risk factors, including atrial fibrillation, advanced age, low ejection fraction, and hypercoagulability. Other important correlates of high thromboembolic risk include valve design, valve position, anticoagulation variability, and time from surgery. Clinical management is further complicated when antithrombotics may need to be interrupted or altered during surgery or pregnancy. At present, vitamin K antagonists are the only approved agents for thromboprophylaxis but are limited because of a narrow therapeutic window and requirement for frequent monitoring. Novel anticoagulants, including inhibitors of factor IIa and Xa, are currently being evaluated and may emerge as alternatives to vitamin K antagonists.