Ca2+ diffusion through dentin of Ca(OH)2 associated with seven different vehicles

This investigation measured the diffusion of Ca2+ through dentin by using Ca(OH)2 associated with various vehicles. After mechanical preparation and removal of smear layer, 41 human premolar teeth were stored individually in flasks containing 800 ml of ultra-pure deionized water for 2855 h. The Ca2+ concentration was measured by atomic absorption spectrophotometry as a function of time. These measurements were divided into two phases: dissolution, to check the loss of Ca2+ from the tooth structure itself, for which all canals were kept empty and open in the absence of medication for 1168 h, and diffusion, in which the specimens were divided into 10 groups (3 control groups: group 1 = water control, group 2 = sealing control, and group 3 = open canal dissolution control; 7 experimental groups in which the whose canals were filled with Ca(OH)2 paste associated with the following vehicles: group 4 = saline; group 5 = polyethylene glycol (Calen); group 6 = glycerin and camphorated parachlorophenol group 7 = camphorated paramonochlorophenol; group 8 = glycerin; group 9 = glycerin and tricresol formaldehyde (TCF); and group 10 = anesthetic solution. This phase lasted 1687 h. A total of 1058 measurements of Ca2+ were made. Regression analysis was used for statistical evaluation. We concluded that diffusion occurred differently for each group: the medications used in the root canals interacted with the dentinal structure or among themselves; the medication coated the dentinal tubule, facilitating the diffusion of Ca2+ into the external part of the root.     

pH and calcium ion release of 2 root-end filling materials

OBJECTIVE: The purpose of this study was to evaluate the pH and calcium ion release of 2 materials used for root-end fillings and perforation repair. STUDY DESIGN: ProRoot and MTA-Angelus were placed in plastic tubes and immersed in glass flasks containing deionized water. After 3, 24, 72, and 168 hours, the water in which each had been immersed was tested to determine the pH changes and released calcium. RESULTS: The values for pH and calcium ion release were slightly higher for MTA-Angelus than ProRoot. The calcium release and pH of both materials were initially higher. CONCLUSION: The results suggest that both materials release calcium and promote alkaline pH.     

Do beta-blockers prolong survival in heart failure only by inhibiting the beta1-receptor? A perspective on the results of the COMET trial

Experimental and clinical studies indicate that carvedilol exerts multiple antiadrenergic effects in addition to beta(1)-receptor blockade, but the prognostic importance of these actions has long been debated. This controversy has now been substantially advanced by the results of the recently completed Carvedilol Or Metoprolol European Trial (COMET), which showed that carvedilol (25 mg twice daily) reduced mortality by 17% when compared with metoprolol (50 mg twice daily), P=.0017--a result that was consistent with the differences seen across earlier controlled trials with beta-blockers in survivors of an acute myocardial infarction and in patients with chronic heart failure. Questions have been raised about the interpretation of these findings in view of the fact that the trial did not use the dose or formulation of metoprolol that was shown to prolong life in a placebo-controlled trial (ie, Metoprolol CR/XL [Controlled Release] Randomized Intervention Trial in Heart Failure). Pharmacokinetic and pharmacodynamic analyses, however, indicate that the dosing regimen of metoprolol selected for use in the COMET trial produces a magnitude and time course of beta(1)-blockade during a 24-hour period that is similar to the dose of carvedilol targeted for use in the trial. These analyses suggest that the observed difference in the mortality effects of metoprolol and carvedilol is not related to a difference in the magnitude or time course of their beta(1)-blocking effects but instead reflect antiadrenergic effects of carvedilol in addition to beta(1)-blockade.     

Mechanical failure of the American Medical Systems Ultrex inflatable penile prosthesis: before and after 1993 structural modification

PURPOSE: The 700 Ultrex (American Medical Systems, Minnetonka, Minnesota) is the only penile prosthesis capable of length and girth expansion. Early experience with the 700 Ultrex showed an increased mechanical failure rate compared with the 700CX, mostly secondary to cylinder failure. In 1993 the Ultrex cylinders were modified. We examined the performance of the Ultrex device before and after modification. MATERIALS AND METHODS: We compared our results with the Ultrex prosthesis before (group 1) and after (group 2) the 1993 modification. We implanted 239 devices from October 1989 to December 1999. A total of 26 patients have died. Followup was obtained on the results of 137 of the remaining 213 implants (64%), including 85 pre-modification devices in 85 patients and 52 post-modification devices in 51, via a mailed questionnaire, telephone survey or chart review. The questionnaire and survey included a 5-point satisfaction scale. Groups 1 and 2 were compared in regard to 3 end points, namely cylinder, mechanical and overall failure. RESULTS: Followup was less than 1 to 136 months (median 92, 25th to 75th percentiles 43 to 108) in group 1 and less than 1 to 92 months (median 46, 25th to 75th percentiles 21 to 75) in group 2. The 5-year Kaplan-Meier estimates of overall, mechanical and cylinder survival in groups 1 and 2 were 64.7%, 70.7% and 80.2%, and 77.7% (p = 0.23), 93.7% (p = 0.017) and 96.2% (p = 0.008), respectively. Overall satisfaction was similarly high in groups 1 and 2 (mean 3.9 and 4 points). CONCLUSIONS: On long-term followup the 1993 modification of the Ultrex cylinders appears to have significantly decreased the propensity of cylinder failure of the pre-modification device.