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Bone adhesive summary.

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  • Bone adhesive summary.

    Many thanks to all those out there who sent in helpful suggestions.
    Sharon is gearing up to try a number of them. I'll post a brief
    message to let the list know what finally worked.


    Following are the suggestions from the generous folks who responded.
    I hope those authors will forgive my light editing to save bandwidth.

    From: "Donal McNally"

    We use dental stone to hold our specimens in place. You have to
    embed the ends of the bone a little, but since your bones are so
    long compared to their width, this should not be a problem. The
    stone (not plaster) is strong in compression and resist the
    specimen 'turning out' quite well.

    From: "Traci Wenzel"

    I don't know what kind of tests she is doing, but we have found
    that Krazy Glue (or cyanoacrylate of any kind) holds bone pretty
    well when glued to acrylic or aluminum...
    ..I've used it for gluing cubes of cancellous bone (~8mm
    square) to plastic for slicing on an Isomet and for gluing cylinders
    of cancellous bone (again ~8mm) to Aluminum disks to prevent the
    ends from slipping during compression tests. Application is simple
    --put a blob of glue on the plastic or aluminum, blot the end of
    bone that you want to glue, and stick it on. It hardens in a few
    seconds and holds very well. I would guess that she might have a
    chance with cortical bone if she could cut off the condyles, giving
    her a smooth regular surface to glue to.

    From: "Richard Hillam"

    We perform alot of mechanical tests on bones that vary from human spines
    to small bones 2mm in diameter.

    The difficulty with finding an adhesive is that most don't like water but
    in order to mechanically test a bone, it must remain hydrated. I've tried
    epoxy but without much success. Depending on the bone shape and test to be
    performed, we use either cyano-acrylate (eg. M=M M-bond 200), commonly
    called Super glue! or green dental cement (Kerr Suprastone). The former
    is very strong but requires thorough surface preparation ie all blood +
    debris removed, scrape away the periosteum then defat using 50/50 ether
    chloroform mixture. You can then go ahead and bond. The latter is not
    an adhesive but is excellent at moulding to the contours of the bone to
    firmly hold it in place whilst compressing, for example. It is very hard,
    non-compressive and once cured it will maintain its strengh in water. We
    use it for compressive tests on spines and vertebrae. It is very
    exothermic during curing!

    What ever you do, try and avoid trimming or cutting the bone to make it
    more convenient, as this obviously affects the mechanical properties. You
    may need to construct a custom jig.

    From: (Young Hui Chang)

    .. have you tried plain
    old cyanoacrylate (on a very clean dry surface; i.e., prepping with
    acetone). Another idea might be to try some dental adhesives. I can't think
    of it at the moment, but I did some work in dental materials a few years
    ago and we were using a few different dental bonding agents.

    From: "Howard J. Dananberg, DPM"
    Jay Phillips, DPM

    Try Histacryl. This is a bone cement used in surgery for small bones. It
    also applicable in nerve repair in Europe. Good Luck.

    From: (Michael Sanders)


    From: mehta@zermatt-ra.SWMED.EDU (Shreefal Mehta)

    One study of microtensile
    testing that was performed by J Rho and R Ashman
    here in Dallas, is published in J Biomech., 26(2):111-119 (1993).

    As also explained in Rho's dissertation, the specimens were inserted
    into 1 mm diameter holes drilled into the ends of rods, and after drying,
    the bone samples were glued in place with a cyanoacrylate glue. The samples
    were then tested in the dry state (no puns intended ;-) ).

    The only reason for your failure with diff glues that i can deduce,
    is that you are trying to keep your specimens wet.
    In that case, it is not really possible to glue them using cyanoacrylate
    or methylmethacrylate glues. However, if you wish
    to pursue the wet specimen approach, then i suggest an underwater
    epoxy that is available at the local hardware store.. It hardens,
    (bnut here is another problem) with an exothermic reaction, even
    under water. It is used to seal boat leaks etc etc etc.

    From: "Amy C. Courtney"

    ..I have successfully tested
    machined specimens as small as 2 mm in diameter and 3 cm long.
    Others in my laboratory have successfully tested whole rat bones
    of similar size using different techniques.

    (and later)

    ..For machined specimens of similar
    dimensions, I have used both custom and off-the-shelf three-jaw chucks
    mounted in an instron machine to hold the ends of the specimens. There
    are some careful techniques required for mounting the specimens, but I
    found it worked well.

    Those in my lab who test rat bones test them in compression, and
    mount the specimens in methylmethacrylate in small vial caps. Two caps
    are used to 'encapsulate' the ends of a vertebrae, one cap is used to
    support the distal end of a femur. The compressive load is applied
    either to the top cap or to the head of the rat femur.

    The methacrylate that I have had success with is 'room
    temperature curing' dental methacrylate, which is probably the same thing
    she has tried already. However, Perhaps the bones are coming out for the
    following reason: When the methacrylate cures, the heat causes fat to
    melt and ooze, creating a very slippery interface rather than a bond with
    the bone. I have found that working carefully to remove soft tissue from
    the ends of the bones, and even drying just the very ends with alcohol
    before embedding helps. This is assuming that the bones are slipping
    out, not actually fracturing at the ends near the embedding site.

    Other colleagues in my lab have tested small samples of
    trabecular bone in tension. They also found the need to clean out the
    very ends of the bone that were actually embedded prior to using
    cyanoacrylate (super glue) to bond the bone ends to endcaps.

    From: "Thomas G. Loebig"

    Have you tried using auto body filler, aka "bondo"? Nonetheless, it
    works well and is used by other researchers. There are various brands
    such as Snowite(sp?), Bondo, etc. Be careful to get the kind without
    fiberglass. I believe that it is a type of epoxy but I never checked
    that out since it is a good "off the shelf" filler available at auto
    parts stores. Like with methacrylates, make sure the surface of the
    bone is dry.

    (And later...)

    Since the bones pull-out before failure, it sounds like these specimens
    are very straight, at least at the ends, with no bumps to grab on to.
    If the bones are not damaged during the test, you might try applying a
    drop or two of SuperGlue (cyanoacrylate) to the tips and reinserting
    them into your blocks. As long as the mating surfaces are clean
    (electronic contact cleaner or rubbing alcohol), the fit is tight, and
    you hold pressure on the joint for about 30 seconds, you will get a
    very strong bond that with the right amount of surface area, will
    provide enough force to hold the specimen until the bone breaks.
    If you can do this, and it works on a new or previously used specimen,
    I would suggest first coating the bonding surface of the bone with a
    release agent such as vaseline or any teflon containing lubricant
    (I don't know if WD-40 would work but you can try it, we use TRI-FLOW
    with Teflon and petroleum lubes). Once the PMMA, Bondo, epoxy, etc.
    sets up, it should be easy (relatively) to remove the bones. You
    should then have a near perfect mold for your bones. Then you can
    clean them and glue them and get on with the test!
    I am assuming that you are doing some type of tensile test and that
    can be a pain. Fixation problems like this are common and a source of
    frustration to us all.
    Reasons for pull-out are most likely that the materials you used
    before don'treally form a chemical bond with the bone and the pores
    in the bone (assuming cortical) are too small for the polymers to
    grab well. The materials are also not much more than fillers and
    therefore not adhesives. Although some of the epoxies have adhesive
    qualities, they must be specially formulated for the application.
    SuperGlue, however, is an adhesive that is used extensively in the
    medical profession for microsurgery when sutures are too large to
    connect tissue. I've been told that it was invented precisely as a
    tissue adhesive but have never found independent confirmation of that.
    I can tell you from personal experience that formulations of the
    methyl- and ethyl- cyanoacrylates are used almost exclusively for
    bonding electrical resistance strain gauges to bone and that they
    work extremely well. Let me know if this works for you, good luck.

    From: "Ed Wachtel"

    We do testing of small trabecular and cortical bone specimens and
    have had excelent success with Lopctite prism 401 cyanoacrylate adhesive.
    Good luck