Metal-ceramic bond strength between a feldspathic porcelain and a Co-Cr alloy fabricated with Direct Metal Laser Sintering technique

PURPOSE: The aim of the present study was to record the metal-ceramic bond strength of a feldspathic dental porcelain and a Co-Cr alloy, using the Direct Metal Laser Sintering technique (DMLS) for the fabrication of metal substrates. MATERIALS AND METHODS: Ten metal substrates were fabricated with powder of a dental Co-Cr alloy using DMLS technique (test group) in dimensions according to ISO 9693. Another ten substrates were fabricated with a casing dental Co-Cr alloy using classic casting technique (control group) for comparison. Another three substrates were fabricated using each technique to record the Modulus of Elasticity (E) of the used alloys. All substrates were examined to record external and internal porosity. Feldspathic porcelain was applied on the substrates. Specimens were tested using the three-point bending test. The failure mode was determined using optical and scanning electron microscopy. The statistical analysis was performed using t-test. RESULTS: Substrates prepared using DMLS technique did not show internal porosity as compared to those produced using the casting technique. The E of control and test group was 222 ± 5.13 GPa and 227 ± 3 GPa, respectively. The bond strength was 51.87 ± 7.50 MPa for test group and 54.60 ± 6.20 MPa for control group. No statistically significant differences between the two groups were recorded. The mode of failure was mainly cohesive for all specimens. CONCLUSION: Specimens produced by the DMLS technique cover the lowest acceptable metal-ceramic bond strength of 25 MPa specified in ISO 9693 and present satisfactory bond strength for clinical use.

Sildenafil versus continuous positive airway pressure for erectile dysfunction in men with obstructive sleep apnea: a comparative study of their efficacy and safety and the patient's satisfaction with treatment / 亚洲男科学杂志(英文版)

<p><b>AIM</b>To assess the efficacy of sildenafil and continuous positive airway pressure (CPAP) in the treatment of concurrent erectile dysfunction (ED) with obstructive sleep apnea (OSA), and to gauge the level of treatment satisfaction in patients and their partners.</p><p><b>METHODS</b>Forty men were treated for 12 weeks with sildenafil 100 mg (20 men) or CPAP during nighttime sleep (20 men). Treatment efficacy was assessed by the rate of successful intercourse attempts, and satisfaction with treatment was assessed by patients' and partners' answers to question 1 of the Erectile Dysfunction Inventory of Treatment Satisfaction.</p><p><b>RESULTS</b>Under sildenafil, 128 of 249 (51.4%) intercourse attempts were successful; under CPAP, 51 of 193 (26.9%) attempts were successful ((c)P < 0.001). Erectile function was improved in both groups. After sildenafil and CPAP treatment, the mean International Index for Erectile Function domain scores were 14.3 and 10.8, respectively ((b)P = 0.025), compared to 7.8 and 7 at baseline, respectively. CPAP and sildenafil were well tolerated. Sporadic episodes of nasal dryness under CPAP and transient headache and flushing under sildenafil were not significant. Fifty percent of patients treated with sildenafil and 25% with CPAP were satisfied with the treatment, and their partners were equally satisfied. The satisfaction scores for both patients and partners under sildenafil were superior to those under CPAP ((c)P < 0.002).</p><p><b>CONCLUSION</b>Both sildenafil 100 mg and CPAP, used separately, had positive therapeutic impact but sildenafil was superior. Patients and their partners were more satisfied with sildenafil for the treatment of ED. However, because of the high proportion of dissatisfied men and partners, new therapeutic agents or a combination of the two methods must be studied further.</p>