I was at my local National Health Service dentist having some root canal work done on a molar that's been grumbling for some time. As a polymer technologist, there's something strangely comforting about dentist's surgeries, one of the few places where people do not object to polymers from the floor to ceiling in the name of hygiene.
Then two unexpected things happened.
Firstly, it was bearable. My dentist sloshes local anaesthetic onto and into your gums so expertly that you could have your jaw removed and not notice.
Secondly, he took me through what he'd done after the drilling, filling and filing was over.
He explained that my root canals were between 1.6 and 1 cm long (that's about 0.75/inch to 0.5/inch long) and that he'd filled them with gutta percha.
I last heard of gutta percha about 20 years ago on my polymer science and technology degree. Polymers are such a big class of chemicals that I felt at least part of the degree's role was to mention polymers in passing so we could bluff our way into any conceivable job in the business. It's stood me in good stead for the past 20 years.
As we polymer technologists know, gutta percha is trans-1,4-polyisoprene and is produced in a bioreactor, or tree. Natural rubber and synthetic analogues of natural rubber are the cis-1,4- polyisoprene isomer. Natural rubber is rubbery, gutta percha isn't. That's because one is trans, and packs together well enough to have a developed crystalline nature. Cis-1,4-polyisoprene packs together badly with only limited crystallinity.
I had always wondered two things. What gutta percha was used for, and why my degree was being taught in the polymers metals and dental technology department of Manchester Polytechnic. That's now renamed as the Centre for Materials Science Research at Manchester Metropolitan University.I had thought, when I thought about it at all, that metallurgy was perhaps a dull kind of chemistry, but couldn't guess that polyisoprene held the link between an exciting course like mine, and dentistry. In one simple answer 20+ years after graduation I found out.
It looks like I've had isoprene at the back of my mind for about half of my life, and all things being equal, I'll have a head full of isoprene to see me thought the remainder. There's something symmetrical about that.