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Home > Common Questions

Common Questions

Who can I contact at the Hard Tissue Research Laboratory?

How should I prepare the specimens I harvest?

Is a special fixative necessary?

How should I package and label the specimens?

How should we ship the specimens to the laboratory?

How long does it usually take for the specimens to be processed?

What about coverslipping the slides once we receive them from the Hard Tissue Research Laboratory?

What's the best way to store the slides for a long time?

COVERSLIPPING ALTERNATIVE:

Who can I contact at the Hard Tissue Research Laboratory?

Call Dr. Rohrer at 612-624-5478 or Hari Prasad at 612-626-2190 between 8:00 am and 5:00 pm Central Time, Monday through Friday. Feel free to leave a message if we're not available for the phone.

How should I prepare the specimens I harvest?

It is best to have as little bone around implants as possible given the constraints of the research project. Adequate fixation and infiltration of resin is enhanced by not having extra bone in the specimens. If the specimen contains a section of the mandible, it is best to remove the inferior cortical plate if possible without harming the implant. The clinical investigator should retrieve and prepare the specimens to as close as possible the ideal size before shipping them to the Hard Tissue Research Laboratory. When the specimens arrive in the laboratory, we will section the implants, buccal-lingually, mesio-distally, or in multiple cross sections, depending on the research protocol, prior to dehydration and infiltration Bone core specimens should be retrieved by as large a trephine as possible. The absolute minimum size of a core is 1mm in diameter and 2mm in length. Of course, the larger the core, the better the results. The bone core should be removed from the trephine prior to sending it to the lab.

Is a special fixative necessary?

The specimens should be fixed in 10% neutral buffered formalin, at least a ten-fold volume of fixative to volume of specimen.The specimens can be shipped in formalin or 70% alcohol. If shipping in alcohol, the specimens should fix at least 24-48 hours in formalin. If shipped overnight, the specimens can be simply wrapped in saturated gauze with the formalin or alcohol.

How should I package and label the specimens?

The specimens should be packaged individually and labeled well IN PENCIL on the outside and on a small piece of white paper on the inside of the container. Ink is not to be used. This primary container should be sealed so there can be no leakage. The primary container should be placed in a leak proof secondary container such as a high quality zip-lock bag which may or may not be labeled. The specimens should be packaged in a strong, crush proof box with enough absorbent packing material to soak up all the liquid should it leak. The box should not be able to be soaked with the liquid should it come out of the containers. Changes in air pressure during air shipment tends to cause formalin to leak out of containers which seem tight.

It is imperative that the specimens be well identified in the containers and also on an identification sheet. The information should include:

1. Your identification number of the specimen

2. Information on the specimen including

How should we ship the specimens to the laboratory?

The specimens should be shipped overnight, preferably with a shipper which can track the shipment all the way to the lab. It is best if one calls the Hard Tissue Research Laboratory at 612.626.2190 or Dr. Rohrer's office at 612.624.5478 to make sure someone will be at the laboratory to receive the shipment when it arrives so it can be immediately logged in and started on the dehydration/infiltration process.

The address for shipping specimens is:

Hard Tissue Research Laboratory
The University of Minnesota School of Dentistry
16-116 Moos Tower
515 Delaware st. S.E
Minneapolis MN 55455

How long does it usually take for the specimens to be processed?

The dehydration and infiltration process takes approximately 1 month. The time for the preparation of the slides depends on the number of specimens, what is required, and how busy the lab is at that time. In general, projects are completed between 60 and 120 days.

What about coverslipping the slides once we receive them from the Hard Tissue Research Laboratory?

THESE SLIDES ARE NOT COVERSLIPPED WHEN SENT FROM OUR LABORATORY. They need to be coverslipped with oil before you view them microscopically or take pictures. Before viewing, use immersion oil or a very clear light machine oil to coverslip the slides. DO NOT TRY TO EVALUATE OR PHOTOGRAPH THE SLIDES WITHOUT COVERSLIPS.

What's the best way to store the slides for a long time?

For long term storage, the slides should be coverslipped with ample oil to prevent drying. Storage at room temperature in the dark is best to avoid fading of the stains.Anytime there is a bubble, dust or anything else in the coverslipping that inhibits photography, simply clean and recoverslip.

COVERSLIPPING ALTERNATIVE:

What we usually do at the Hard Tissue Research Laboratory is use immersion oil. As an alternative to placing a coverslip over the oil which often traps very small bubbles, I put the oil on and spread it around the area in which I'm interested and then, instead of putting a coverslip on, I use a coverslip as a squeegee and draw it across the slide firmly at about a 45 degree angle. This seems to leave a good layer of oil for viewing with few or no bubbles. Of course, it gathers dust immediately so I clean the slide carefully if I can't cover it up right away.

 
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