Getting my teeth into some latte art

LatteArt_CoffeeworksEach year, in the UK, there are approximately 160 000 hip or knee replacements. Additionally, many of us will have a dental implant during our lifetime. How is this linked with coffee? The answer lies in the differences between a latte and a cappuccino.

To support the artwork that can be seen on many a latte, the milk foam used for the drink is a fine “micro-foam”. It is quite a soft structure. On the other hand a cappuccino is more rigid, being made out of a larger foam structure. The different way that a barista froths the milk for a cappuccino compared to a latte means that the peak structures that can be formed in the cappuccino, are far more difficult to create in a latte, the cappuccino has more of a “meringue like” froth.

Joint replacements and dental implants were traditionally made from solid metal. This meant that the majority of the load that was put on the joint (by walking or chewing for example) was carried by the implant. It is thought that this was one of the reasons that joint replacements and dental implants eventually failed; the bond between the bone and the implant became progressively weaker in a process called “aseptic loosening”. In recent years there have been many improvements to joint replacements/implants so as to avoid these problems. One such improvement is to manufacture the implant out of a metallic foam instead of solid metal.

Cappuccino showing peaks in the foamJust like a latte or a cappuccino, the way that the metal foam responds to stress (and its rigidity) is dependent on many factors including the size of the bubbles in the foam and exactly what the foam is made from. (Imagine comparing a cappuccino with a soya milk cappuccino). By manipulating the structure of the metal foam, an implant can be made that behaves almost exactly as bone does when stress is placed on it. Together with the inherently stronger bone-implant bond created by the bone growing into the ‘bubbles’ of the implant foam, this is thought to reduce the risk of implant failure owing to ‘aseptic loosening’.

I am indebted to Michaela and Juan of Poppy’s Place for patiently showing me the art (and science) of making coffee. With good coffee (from Climpson & Sons) and knowledgeable barista-teachers, it is a place that I am sure that I will return to very soon. Michaela and Juan assured me that if I would like to see a properly rigid milk foam I should order a “babyccino”. There are however limits to the amount that I am prepared to ‘suffer for my science’ and the babyccino is it. If you would like to properly investigate the effect of bubble structure on the ability of an implant (dental or otherwise) to take stress, I suggest you compare a latte with a babyccino. If, like me, you like your coffee, a cappuccino will definitely suffice.

 

3 Responses to Getting my teeth into some latte art
  1. Julia says:

    I’ve been thinking today at work about a problem, then took a cup of coffee, which as a tea drinker I rarely do, and here it is: I realised I can look up the basics at the “Blue Sky Thinking”. It brought me closer to solving my problem. A great example of “bean thinking” efficiently. However, my employer might BEan THINKing differently: I spent then quite some time reading the Daily Grind posts. Really liked them. Are metallic foams already used in joint replacements or is it still an intention?

    • beanthinking says:

      Although this site concentrates on coffee, I think it’s ok to drink tea sometimes šŸ˜‰ Glad to hear that the site brought you closer to solving your problem.

      To answer the question, yes, I think that they are already being used in joint replacements but maybe not yet routinely (I found this website with some info: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3796997/ ). For dental implants, metal foams are currently used as one method (among several possible methods) of reducing the problem of the implant failure due to the stress load on the implant.

      So in summary, yes, metal foams do seem to already be in use but you will not necessarily get a metal foam ‘joint’ were you to have a hip replacement tomorrow.

  2. Julia says:

    Thanks for the detailed answer to my question!

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