Article
Sometimes we need a push, a deadline, or even a threat to get us into action. Minamata provides us with a serious push with regard to what we will be using to restore posterior teeth in the future.
Minamata is a city in Japan. A chemical company was established there in 1908 (Chisso Co) and, in 1932, they started making acetaldehyde, a chemical which is used, with others, to make plastics. Mercury was used as a catalyst. It appears that organic mercury was dumped into the ocean; the locals (and the local cats) ate the fish and shellfish. Cats started going crazy, sometimes throwing themselves into the sea. Humans had difficulty walking, talking and eating; some had convulsions and died. The resultant mercury poisoning affected 60,000 people and was first reported in 1956, being then and now one of the world's worst environmental disasters. The Ministry of Trade and Industry blocked researchers from getting access to company waste and eventually made the company install a cyclator (sedimentation system) and, by 1959, there was agreement with patients of the ‘Minamata disease’ to give sympathy money in return for promising not to sue. In 1968, the Government officially announced the cause and, in 1973, Chisso Co lost a lawsuit, the largest settlement in Japan at that time.1
If we move on 80 years from the initial use of mercury in the factory, Minamata has become a model environmental city. Discussions started in February 2009 and culminated in a conference held there to discuss the worldwide future of mercury. Hence, in Minamata in October 2013, 147 countries signed a treaty on minimizing the use of mercury. Alongside the use of mercury in fertilisers and industry, there is a section (Annex A, Part II) on measures to be taken to phase down the use of dental amalgam.2
These are:
All of these seem eminently sensible, but it is the recommendation concerning insurance programmes that favour the use of dental amalgam which is of greatest relevance to dentistry in the UK. In particular, it could affect NHS dentistry, in which the fee structure might be considered to discourage the use of alternative materials such as resin composite, because they take longer to place3 and are therefore more expensive. The amalgam vs composite debate was given a lengthy airing in the 40th Anniversary issue of Dental Update in May 20134 and readers were given a view, on that occasion, on what an ideal amalgam replacement might look like. This material may well be:
In addition, if speed of placement is a consideration, might there also be some consideration to points 2 and 4 above, for this new material to be self curing (although that might seem to be turning the clock back!) because it has been determined that 86% of the mean time difference between placing an amalgam and composite restoration in a posterior tooth is accounted for by the acid etching, washing/drying and light curing.5
When might this material become available? Hopefully, before the Minamata arrangements come into effect! When might that be? Some consider that this will be in the distant future (Personal Communication, Graham Stokes, British Dental Association representative, speaking at the European Dental Materials Conference in Birmingham, August 2013), but I tend to agree with Chris Lynch and Nairn Wilson that it is likely to be in circa five years, and that the teaching related to dental amalgam in dental schools will be phased out, starting with the students enrolling in 2015.6 In other words, we had all better become adept at the placement of resin composite restorations (or their mercury-free successor mentioned above) in posterior teeth! Just as well that the results of a survey in 2009/2010 indicated that present day dental students are receiving greater experience in the teaching of posterior composite than their predecessors.7 Nevertheless, for those who graduated earlier, a lot of courses will need to be organized! In that regard, an article in the present issue of Dental Update examines the current status of glass ionomer as an alternative material for use in loadbearing situations in posterior teeth (pp840-844).
It has been a momentous year for Dental Update, as we celebrated 40 years of successful evidence-based, peer-reviewed publishing since our first issue in 1973. I hope that you have enjoyed reading the past year's issues and that the topics which we have covered have been of value to you in your everyday clinical practice, let alone providing you with verifiable CPD. Of course, each issue would not be possible without our super authors – thanks to all of them, our reviewers, and the help of everyone in the production office at Guildford, ably led by Angela Stroud. It remains therefore for me to wish you an enjoyable festive season and to wish you every happiness in 2014.