Influence of surface properties of resin‐based composites on in vitro Streptococcus mutans biofilm development

The aim of this in vitro study was to evaluate the influence of physicochemical surface properties of resin‐based composites on Streptococcus mutans biofilm formation. Specimens were prepared from each of four resin‐based composites by polymerization against Mylar strips. Half of the number of specimens received no further surface treatment, whereas the other half were subjected to a polishing treatment. Surface roughness (SR) and topography were assessed using profilometry and atomic force microscopy. Surface free‐energy (SFE) was determined, and the chemical surface composition was analysed by X‐ray photoelectron spectroscopy (XPS). S. mutans biofilms were formed on the surface of the resin‐based composite specimens for either 48 or 96 h using an artificial mouth system (AMS). Polishing caused a significant decrease in SFE, and XPS analysis indicated an increase of surface silicon and a decrease of surface carbon. Only for Grandio was a significant increase in SR identified after polishing, which was probably related to the higher concentration of filler particles on its surface. Significantly less S. mutans biofilm formation was observed on polished resin‐based composites than on unpolished resin‐based composites. These results indicate that the proportions of resin matrix and filler particles on the surface of resin‐based composites strongly influence S. mutans biofilm formation in vitro, suggesting that minimization of resin matrix exposure might be useful to reduce biofilm formation on the surface of resin‐based composites.     

Gonadal function recovery in very long-term male survivors of childhood cancer

BackgroundAlthough gonadal toxicity has been reported, no data are available on recovery of gonadal function in very long-term survivors of childhood cancer. Inhibin B is a novel reliable serum marker which has been shown to be of value in childhood cancer survivor studies to identify risk groups for impaired gonadal function, but consecutive long-term follow-up studies using serum inhibin B as a marker are not available.ObjectiveTo evaluate possible recovery of gonadal dysfunction over time in adult male survivors of childhood cancer.MethodsIn this retrospective study, adult male long-term childhood cancer survivors (n = 201) who visited our outpatient late effects clinic were included and we used inhibin B as a surrogate marker for gonadal function.ResultsMedian age at diagnosis was 5.9 years (range 0.0–17.5) and discontinuation of treatment was reached at a median age of 8.2 years (range 0.0–20.8). Inhibin B levels were first measured after a median follow-up time of 15.7 years (range 3.0–37.0). Median interval between the first (T1) and second measurement (T2) was 3.3 years (range 0.7–11.3). Median inhibin B level was 127 ng/L (range 5–366) at T1 and 155 ng/L (range 10–507) at T2. The prediction model suggests that inhibin B levels do not normalise in survivors with a very low Inhibin B level at T1.ConclusionsOur results suggest that recovery of gonadal function is possible even long after discontinuation of treatment. However, this recovery does not seem to occur in survivors who already reached critically low inhibin B levels after discontinuation of treatment.     

Optimizing Online Suicide Prevention: A Search Engine-Based Tailored Approach

Search engines are increasingly used to seek suicide-related information online, which can serve both harmful and helpful purposes. Google acknowledges this fact and presents a suicide-prevention result for particular search terms. Unfortunately, the result is only presented to a limited number of visitors. Hence, Google is missing the opportunity to provide help to vulnerable people. We propose a two-step approach to a tailored optimization: First, research will identify the risk factors. Second, search engines will reweight algorithms according to the risk factors. In this study, we show that the query share of the search term “poisoning” on Google shows substantial peaks corresponding to peaks in actual suicidal behavior. Accordingly, thresholds for showing the suicide-prevention result should be set to the lowest levels during the spring, on Sundays and Mondays, on New Year’s Day, and on Saturdays following Thanksgiving. Search engines can help to save lives globally by utilizing a more tailored approach to suicide prevention.     

Two cases of pisiform bone impingement syndrome after proximal row carpectomy

Proximal row carpectomy (PRC) is an established surgical procedure used to treat post-traumatic osteoarthritis of the wrist with sparing of the midcarpal joint and advanced aseptic necrosis such as lunatomalacia. Proximalization of the distal carpal row following PRC may lead to secondary problems such as radiocarpal impingement. At follow-up, two of our patients complained about ulnar-sided wrist pain after proximal row carpectomy. Computed tomography (CT) scans were taken for both patients with an additional magnetic resonance imaging scan for one patient. The CT scan revealed clear osteolysis consistent with a pisiform bone impingement on the ulnar styloid process in both the cases, and also on the hamate in one patient. An impingement syndrome of this nature has not previously been described and should be kept in mind when patients report ulnocarpal symptoms after PRC.