TMJ response to mandibular advancement surgery: an overview of risk factors

Objective: In order to understand the conflicting information on temporomandibular joint (TMJ) pathophysiologic responses after mandibular advancement surgery, an overview of the literature was proposed with a focus on certain risk factors. Methods: A literature search was carried out in the Cochrane, PubMed, Scopus and Web of Science databases in the period from January 1980 through March 2013. Various combinations of keywords related to TMJ changes [disc displacement, arthralgia, condylar resorption (CR)] and aspects of surgical intervention (fixation technique, amount of advancement) were used. A hand search of these papers was also carried out to identify additional articles. Results: A total of 148 articles were considered for this overview and, although methodological troubles were common, this review identified relevant findings which the practitioner can take into consideration during treatment planning: 1- Surgery was unable to influence TMJ with preexisting displaced disc and crepitus; 2- Clicking and arthralgia were not predictable after surgery, although there was greater likelihood of improvement rather than deterioration; 3- The amount of mandibular advancement and counterclockwise rotation, and the rigidity of the fixation technique seemed to influence TMJ position and health; 4- The risk of CR increased, especially in identified high-risk cases. Conclusions: Young adult females with mandibular retrognathism and increased mandibular plane angle are susceptible to painful TMJ, and are subject to less improvement after surgery and prone to CR. Furthermore, thorough evidenced-based studies are required to understand the response of the TMJ after mandibular advancement surgery

CO2 quota attribution effects on the European electricity system comprised of self-centred actors

We propose to rethink collaboration between the European countries to robustly materialise the electricity system of the near future. The European countries all agree that carbon dioxide (CO2) emissions need to be decreased. The dividing question is who must contribute by how much. Three aspects of collaboration are investigated and set into relation to one another. First, the individual countries can be attributed a CO2 emission quota in different ways. Second, they can collaborate by relaxing their need for autonomy, e.g. becoming less self-sufficient by placing generation capacity in countries with better prerequisites. Third, collaboration can also be strengthened by extending the cross-border transmission grid. We investigate a near future European electricity system where the primary source of emission-neutral electricity is coming from different variable renewable energy sources, but which also includes current and planned nuclear, coal, lignite and gas-fuelled power plants. We show that different CO2 emission quota attributions have an immense effect on the required local CO2 prices. Furthermore, we investigate how this influences the technology mix in the individual countries. We conclude that it is significantly easier for certain countries to decarbonise their electricity production than for others. The difficulty in the specific country depends strongly on how emission allowances are allocated in Europe. Deep collaboration between the countries leads both to a lowered total system cost and, perhaps even more importantly, to CO2 emissions and required CO2 prices that are much more equal between the European partners