Effect of self-etch adhesives on self-sealing ability of high-copper amalgams

Statement of the Problem: Similar to conventional amalgam, high-copper amalgam alloy may also undergo corrosion, but it takes longer time for the resulting products to reduce microleakage by sealing the micro-gap at the tooth/amalgam interface

Purpose: The aim of this study was to evaluate the effect of self-etch adhesives with different pH levels on the interfacial corrosion behavior of high-copper amalgam restoration and its induction potential for self-sealing ability of the micro-gap in the early hours after setting by means of Electro-Chemical Tests [ECTs]

Materials and Method: Thirty cylindrical cavities of 4.5mm x 4.7mm were prepared on intact bicuspids. The samples were divided into five main groups of application of Adhesive Resin [AR]/ liner/ None [No], on the cavity floor. The first main group was left without an AR/ liner [No]. In the other main groups, the types of AR/liner used were I-Bond [IB], Clearfil S[3] [S[3]], Single Bond [SB] and Varnish [V]. Each main group [n=6] was divided into two subgroups [n=3] according to the types of the amalgams used, either admixed ANA 2000 [ANA] or spherical Tytin [Tyt]. The ECTs, Open Circuit Potential [OCP], and the Linear Polarization Resistance [LPR] for each sample were performed and measured 48 hours after the completion of the samples

Results: The Tyt-No and Tyt-IB samples showed the highest and lowest OCP values respectively. In LPR tests, the R[p] values of ANA-V and Tyt-V were the highest [lowest corrosion rate] and contrarily, the ANA-IB and Tyt-IB samples, with the lowest pH levels, represented the lowest R[p] values [highest corrosion rates]

Conclusion: Some self-etch adhesives may increase interfacial corrosion potential and self-sealing ability of high-copper amalgams

Effects of ascorbic acid on sperm motility, viability, acrosome reaction and DNA integrity in teratozoospermic samples

Oxidative stress in teratozoospermic semen samples caused poor assisted reproductive techniques [ART] outcomes. Among antioxidants, ascorbic acid is a naturally occurring free radical scavenger and as such its presence assists various other mechanisms in decreasing numerous disruptive free radical processes. The main goal of this study was to evaluate potential protective effects of ascorbic acid supplementation during in vitro culture of teratozoospermic specimens. Teratozoospermic semen samples that collected from 15 volunteers were processed, centrifuged and incubated at 37°C until sperm swimmed-up. Supernatant was divided into four groups and incubated at 37°C for one hour under different experimental conditions: Control, 10 micro m A23187, 600 micro m ascorbic acid and 10 micro m A23187+600 micro m ascorbic acid. After incubation sperm motility, viability, acrosome reaction, DNA damage and malondialdehyde levels were evaluated. Our results indicated that after one hour incubation, ascorbic acid significantly reduced malondialdehyde level in ascorbic acid group [1.4 +/- 0.11 nmol/ml] compared to control group [1.58 +/- 0.13 nmol/ml] [p<0.001]. At the end of incubation, progressive motility and viability in ascorbic acid group [64.5 +/- 8.8% and 80.3 +/- 6.4%, respectively] were significantly [p<0.05 and p<0.001, respectively] higher than the control group [54.5 +/- 6.8% and 70.9 +/- 7.3%, respectively]. A23187 significantly [p<0.0001] increased acrosome reaction in A23187 group [37.3 +/- 5.6%] compared to control group [8.5 +/- 3.2%] and this effect of A23187 attenuated by ascorbic acid in ascorbic acid+A23187 group [17.2 +/- 4.4%]. DNA fragmentation in ascorbic acid group [20 +/- 4.1%] was significantly [p<0.001] lower than controls [28.9 +/- 4.6%]. In vitro ascorbic acid supplementation during teratozoospermic semen processing for ART could protect teratozoospermic specimens against oxidative stress, and it could improve ART outcome