Preparing Specimens: Teeth and Calcified Tissue

Collecting and Storing Specimens

  1. Have all containers, tools, labeling instruments, and storage systems well organized in advance. Use only paper envelopes to package teeth. Do not use plastic envelopes. A standardized data entry form can be pre-printed or stamped on paper envelopes to enable efficient and complete data recording both during and after the specimen is collected.
  2. Never use any chemical to preserve or store teeth. If jaw fragments are preserved with teeth left in them, treatment with alcohol, formalin, etc. will permanently harden the connective tissue attachments between teeth and bone, making extraction extremely difficult. Instead of using a chemical preservative, refer to paragraph 5 below.
  3. Keep specimens free of contamination. Place teeth directly in envelopes without laying them on the ground where they will pick up sand or grit.
  4. Organize the sample by species. Primarily because of size differences, different processing methods are used for teeth of different species. Keep specimens from each species separate, in identification, storage, and packaging systems. Fisher canine teeth are sexually dimorphic and the great size difference makes necessary separate grouping of teeth from males and females.
  5. Store teeth in a cool and dry place. In paper envelopes, the teeth will dry without rotting. In sealed plastic envelopes, there will be decomposition of soft tissues associated with the teeth, creating an undesirable nuisance factor for technicians who handle the teeth later on. If teeth are to be stored for several months or years before sending them for analysis, store them cleaned and frozen. Enclose the envelopes within a plastic bag to avoid frost accumulation during storage.
  6. Always double-check all specimen identifications, both on the container and on inventory listings, to make sure no number is incorrectly written, omitted, or duplicated.

Tooth Extraction and Cleaning

  • Live or Recently Killed Animals: It is important to extract the tooth without breaking off the root tip where the cementum annuli are most distinct. A tooth can be extracted from a live animal or fresh carcass by using a dental elevator to carefully but completely loosen the tissue around the entire tooth circumference. Then, it is pulled straight out with an extractor or similar tool. The attachment between incisor and mandible of the ungulate is largely soft tissue that can be severed by cutting with a sharp knife on either side of the tooth. After the cuts, the tooth can be loosened by gently twisting and rocking it before pulling with an extractor or pliers.
  • SkullsĀ or Mandibles: Histological damage to tooth tissues is caused by exposure to excessive heat and/or chemical agents, such as bleach. Use a hot water bath at 70-90 degrees Centigrade for 4-6 hours to loosen the teeth for extraction, or prepare them for cleaning. Teeth will be loosened from smaller specimens (e.g. marten skull/mandible) more quickly than larger (e.g. coyote or wolf). Use the lower limits of temperature and shorter times for smaller specimens. After the hot water bath treatment, dirt or sand can be wiped off the tooth with a frequently changed piece of nylon net fabric. A very firm wiping with the nylon net leaves the underlying cementum intact. On the other hand, cleaning the tooth with a sharp instrument or rotary tool can severely damage the cementum.