Dental Metal Matrix Composites: The Effects of the Addition of Titanium Nanoparticle Particles on Dental Amalgam.

Dental amalgams have been used by dentists for the restoration of posterior human teeth. However, there have been concerns about the release of mercury from amalgams into the oral cavity. The objective of the present research is to study the effect of titanium (Ti) nanoparticles on the microstructural mechanism of the release of mercury vapor in two commonly used brands of dental amalgam (the Dispersalloy: 11.8% Cu; the Sybralloy: 33% Cu). Ti powder was added to both the Dispersalloy and the Sybralloy in increments of 10 mg up to 80 mg. The addition of Ti powder to both brands of dental amalgam has been found to result in a considerable decrease in Hg vapor release. The decrease in the Hg vapor release due to Ti addition has been explained by the formation of strong Hg-Ti covalent bonds, which reduce the availability of Hg atoms for evaporation. The Ti atoms in excess of the solubility limit of Ti in Hg reside in the grain boundaries, which also reduces the evaporation of Hg from the amalgam. The binding of Hg with Ti via a strong covalent bond also results in a significant improvement in mechanical properties such as Vickers hardness.

Determination and Calculations of Mercury Vapor Concentration and Energy Released from Freshly Condensed Dental Amalgams Having Various Copper Percentages within the Alloy.

Dental amalgam is an alloy consisting of a mixture of fine metallic powder of silver, tin, zinc, copper, and a trace amount of palladium in combination with about fifty percent elemental mercury that forms a matrix phase. Dental amalgams consisting of a high-copper content are the most common types of alloys currently utilized for the restoration of decayed, broken, and fractured posterior human teeth. The present research objective was primarily to improve the material properties by determining and analyzing the amount of mercury vapor released from dental amalgam received from eight different commercial brands. The mechanical hardness of the alloys was found to increase with an increase in copper content in the amalgam. The effect of copper addition on material aging was also studied. During the release of mercury vapor, the corresponding energies associated with the release of mercury vapor from each sample were determined for each successive measurement. The results indicated that increasing the copper content of the amalgam counters the release of mercury vapor from posterior teeth and improves the hardness properties.

Can Home-Based HIV Rapid Testing Reduce HIV Disparities Among African Americans in Miami?

Sixty percent of African Americans have had an HIV test, yet this population disproportionately contributes to AIDS mortality, suggesting that testing is not occurring early enough to achieve optimal outcomes. OraQuick, the first Food and Drug Administration-approved home-based HIV rapid test (HBHRT) could potentially increase testing rates. We assessed whether community health workers (CHWs) paired with HBRHT could improve HIV screening and health care access among African Americans in Miami, Florida. In October-November 2013, 60 African Americans were enrolled and randomized to the experimental condition, which received CHW assistance to complete HBHRT, or the control condition, which were instructed to complete HBHRT independently. Intervention participants were significantly (p ≤ .05) more likely than control participants to complete HBHRT and, if positive, get linked to HIV care (100% vs. 83%) χ(2) (1, N = 60) = 5.46, p ≤ .02. We concluded that CHW-assisted HBHRT may be a promising strategy to improve HIV testing and care among African Americans.

Strategies to Improve HIV Testing in African Americans.

Only 17% of Miami-Dade County residents are African American, yet this population accounts for 59% of the county's HIV-related mortality. The Centers for Disease Control and Prevention recommend annual testing for persons at increased risk for HIV, but 40% of African Americans have never been tested. OraQuick® (OraSure Technologies, Inc., Bethlehem, PA), the first US Food and Drug Administration-approved home-based HIV rapid test (HBHRT), has the potential to increase testing rates; however, there are concerns about HBHRT in vulnerable populations. We conducted focus groups in an underserved Miami neighborhood to obtain community input regarding HBHRT as a potential mechanism to increase HIV testing in African Americans. We queried HIV knowledge, attitudes toward research, and preferred intervention methods. Several HIV misconceptions were identified, and participants expressed support for HIV research and introducing HBHRT into the community by culturally appropriate individuals trained to provide support. We concluded that community health workers paired with HBHRT were a promising strategy to increase HIV testing in this population.