So-called “Janus” drugs with two molecular “faces” may help address the pressing need for new treatments for herpes simplex virus (HSV). The emergence of resistance to common antiviral drugs such as acyclovir is an increasing problem, especially for patients with weakened immune systems. A team led by Yu-Chen Jiang at Sichuan University, and Hui Feng, Central South University, Changsha, review key strategies for new ways to halt the multiplication of HSV. One of the most promising involves drugs that, like acyclovir, mimic the molecular components of DNA and therefore interfere with the manufacture of viral DNA. Two key DNA components are purines and pyrimidines. The Janus drug molecules have one side that mimics purines while the other side mimics pyrimidines, allowing a double-hit against virus multiplication.

Increased levels of a protein produced in response to stress cause abnormal tooth development. Similar ‘heat shock’ proteins, including Hsp 25 and Hsp 27, have previously been implicated in the origin and formation of teeth, but no one had looked at Hsp 60. Tamás Papp from the University of Debrecen, Hungary, and colleagues examined the expression pattern of Hsp 60 in the lower incisors of mice. They found high levels of the protein in tooth germs, in layers inside the enamel organ called the stratum intermedium, ameloblasts and in cells of the outer dental pulp. The authors applied extra amounts of Hsp 60 to the teeth of embryonic mice and observed morphological defects in the precursor cells that eventually form teeth. The findings suggest that Hsp 60 could be involved in dental disease.

An orthodontic cement showing sustained release of calcium (Ca) and phosphate (P) ions may promote enamel remineralization. Fixed orthodontic attachments allow bacteria to accumulate causing enamel demineralization and white spot lesions. Dental cements formed from calcium phosphate (CaP) composites can release ions and prevent demineralization, however, these composites lack the required mechanical strength. Now, Hockin Xu at the University of Maryland, US, and colleagues report a nanoparticle-containing composite that shows sustained release of Ca/P ions over 14 days with an enamel bond strength similar to commercial orthodontic cements. The cement, formed from CaP nanoparticles mixed with a methacrylate-based resin, can be replenished with ions by placing it in Ca and P solutions, which may be possible using mouthwash. The CaP nanoparticle-based material was repeatedly re-charged with no observed decrease in ion release.

A sensitive spectroscopy technique could provide a simple, non-invasive way of measuring the extent of dental enamel erosion. Tooth enamel is prone to softening and erosion caused by consuming acidic foods and drinks, and a highly sensitive and non-destructive way of measuring the resulting damage is needed. Tae-Yub Kwon at Kyungpook National University and co-workers across South Korea compared an existing enamel microhardness test (Vickers) with a technique called attenuated total reflection Fourier transform infrared spectroscopy, or ATR-FTIR, capable of revealing microscopic changes on a molecular level. The team immersed cattle teeth in ten different acidic drinks, and interpreted the resulting ATR-FTIR spectra. Their method proved more sensitive than the Vickers test, giving detailed insights into surface hardness and erosion. Crucially, using ATR-FTIR would allow scientists to monitor enamel changes repeatedly in the same teeth over time.