Name: systematic assessment of mammalian skull specimens for dental and temporomandibular joint pathology
Uploaded: 2022-08-22T15:00:00
Description: Watch this Scientific Journal Video about Systematic Assessment of Mammalian Skull Specimens for Dental and Temporomandibular Joint Pathology at JoVE.com

The authors thank the Department of Ornithology and Mammalogy, California Academy of Sciences, San Francisco, the Museum of Vertebrate Zoology, University of California, Berkeley, and the Museum of the North, University of Alaska, Fairbanks, for making their collections available for this research.

The present study was conducted using specimens from the Department of Ornithology and Mammalogy, California Academy of Sciences, San Francisco, the Museum of Vertebrate Zoology, University of California, Berkeley, and the Museum of the North, University of Alaska, Fairbanks. Permission to examine skull specimens and publish works from the data was obtained from the museums that own and manage each collection.
1. Specimen selection and documentation
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	<li>Document specim...

<ol>
	<li>Reif, W. E., Hecht, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evolution+of+Dermal+Skeleton+and+Dentition+in+Vertebrates.">Evolution of Dermal Skeleton and Dentition in Vertebrates.</a> Evolutionary Biology: Volume 15. , 287-368 (1982).</li><li>Mallat, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ventilation+and+the+origin+of+jawed+vertebrates:+A+new+mouth.">Ventilation and the origin of jawed vertebrates: A new mouth.</a> Zoological Journal of the Linnean Society. 117 (4), 329-404 (1996).</li><li>Glatt, S. E., Francl, K. E., Scheels, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+survey+of+current+dental+problems+and+treatments+of+zoo+animals.">A survey of current dental problems and treatments of zoo animals.</a> International Zoo Yearbook. 42 (1), 206-213 (2008).</li><li>Kapoor, V., Antonelli, T., Parkinson, J. A., Hartstone-Rose, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oral+health+correlates+of+captivity.">Oral health correlates of captivity.</a> Research in Veterinary Science. 107 (1), 213-219 (2016).</li><li>Norton, B. B., Tunseth, D., Holder, K., Briggs, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Causes+of+morbidity+in+captive+African+lions+(Panthera+leo)+in+North+America,+2001-2016.">Causes of morbidity in captive African lions (Panthera leo) in North America, 2001-2016.</a> Zoo Biology. 37 (5), 354-359 (2018).</li><li>Bergman, A., Olsson, M., Reiland, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Skull-bone+lesions+in+the+Baltic+grey+seal+(Halichoerus+grypus).">Skull-bone lesions in the Baltic grey seal (Halichoerus grypus).</a> Ambio. 21 (8), 517-519 (1992).</li><li>Mortensen, P., Bergman, A., Bignert, A., Hansen, H. 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E., Eriksen, T., Baelum, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Periodontal+disease+in+research+beagle+dogs+-+An+epidemiological+study.">Periodontal disease in research beagle dogs - An epidemiological study.</a> Journal of Small Animal Practice. 49 (12), 610-616 (2008).</li><li>Constantino, P. J., Lee, J. J. W., Morris, D., Lucas, P. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adaptation+to+hard-object+feeding+in+sea+otters+and+hominins.">Adaptation to hard-object feeding in sea otters and hominins.</a> Journal of Human Evolution. 61 (1), 89-96 (2011).</li><li>Winer, J. N., Liong, S. M., Verstraete, F. J. 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M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dental+and+temporomandibular+joint+pathology+of+the+kit+fox+(Vulpes+macrotis).">Dental and temporomandibular joint pathology of the kit fox (Vulpes macrotis).</a> Journal of Comparative Pathology. 167 (1), 60-72 (2019).</li><li>Arzi, B., Winer, J. N., Kass, P. H., Verstraete, F. J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Osteoarthritis+of+the+temporomandibular+joint+in+Southern+sea+otters+(Enhydra+lutris+nereis).">Osteoarthritis of the temporomandibular joint in Southern sea otters (Enhydra lutris nereis).</a> Journal of Comparative Pathology. 149 (4), 486-494 (2013).</li><li>Briggs, K. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dentition+of+the+Northern+elephant+seal.">Dentition of the Northern elephant seal.</a> Journal of Mammalogy. 55 (1), 158-171 (1974).</li><li>Verstraete, F. J. M., Terpak, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anatomical+variations+in+the+dentition+of+the+domestic+cat.">Anatomical variations in the dentition of the domestic cat.</a> Journal of Veterinary Dentistry. 14 (4), 137-140 (1997).</li><li>Fritzell, E. K., Haroldson, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Urocyon+cinereoargenteus.">Urocyon cinereoargenteus.</a> Mammalian Species. 189, 1-8 (1982).</li><li>Chiasson, R. 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E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Etiopathogenesis+of+feline+dental+resorptive+lesions.">Etiopathogenesis of feline dental resorptive lesions.</a> Veterinary Clinics of North America: Small Animal Practice. 22 (6), 1385-1404 (1992).</li><li>van Houte, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+micro-organisms+in+caries+etiology.">Role of micro-organisms in caries etiology.</a> Journal of Dental Research. 73 (3), 672-681 (1994).</li><li>Thrall, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Textbook of Veterinary Diagnostic Radiology. , (2012).</li><li>Tsugawa, A. J., Verstraete, F. J. 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The anatomy of the teeth and jaws is a quintessential example of divergent evolution and is a true reflection of a species&#39; natural history, behavior, and health status. An individual&#39;s oral health may play directly into their survival and fitness. The current study outlines a systematic, reproducible, and detailed manner of assessing the dental health and TMJ abnormalities of museum specimens that may reflect pathology in live populations.
Despite dental diseases universally affecting...

The development of jaws and teeth marks a critical time point in the evolution and development of vertebrates. While jaws initially developed as part of a mechanism of respiration in aquatic and marine species, teeth offered a new manner of apprehending and processing prey items1,2. Since the development of jaws and teeth, organisms have evolved innumerable variations in anatomy that correspond to their function and reflect the ecologic role to which they belong. Due to their mineralized nature, teeth and skulls represent a bounty of information that persists in the environment and fossil record and can offer myriad insights into the ecology, health status, and behavior of individuals and, by extension, species.
The acquisition of information pertaining to the teeth and jaws of animals and characterizing form and pathology has many benefits. Recognizing common disease processes can improve conservation efforts of wild species and optimize the care of captive animals3,4,5. For example, information gleaned from museum skull specimens has been used to make inferences on the exposure of the Baltic grey seal (Halichoerus grypus) and harbor seals (Phoca vitulina) to environmental pollutants such as organochlorines over time6,7, although a causative relationship between orofacial lesions and pollutants has not been confirmed. Furthermore, diseases of the oral cavity are some of the most prevalent diseases in domestic species, and understanding the oral health status of wild species may advance the clinical medicine and management of domestic species8,9.
As animals have developed such variation in normal craniofacial shape and dentition, it can be challenging to characterize and compare these aspects between species. Understanding the ecology and natural behavior of an organism, as well as its typical environment, is imperative before attempting to examine its skull. Doing so will drive the formation of questions and hypotheses about a particular species&#39; dentition and inevitably enrich the conclusions from data analysis. For example, recognizing that the typical diet of the Southern sea otter (Enhydra lutris nereis) includes hard-shelled mollusks, crustaceans, and echinoderms is essential to contextualize the degree and effect of attrition and/or abrasion of the teeth10,11. Although one can assume the likelihood that an individual of a species will develop certain dental diseases, it is critical to have a systematic, precise, and reproducible protocol for evaluating dental pathology. This should include an appraisal of occlusion, anatomical and developmental findings, periodontal disease, endodontal findings, and temporomandibular joint (TMJ)&#160;pathology. Developing such a protocol with similar statistical analysis will allow for a detailed comparison of dental and TMJ disease from species to species. A systematic method has been utilized to characterize dental and temporomandibular joint pathology in many mammalian species and has proven to be translatable to organisms with diverse forms11,12,13,14,15,16,17,18,19,20,21,22,23,24.
To compare future data on additional species, it is important to have an accepted method for assessing diseases of the teeth and jaws that can be applied to a variety of species. This article aims to detail a standardized and organized approach for assessing the dental and TMJ&#160;pathology of skull specimens.

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		<tr>
			<td>Arctos Collaborative Collection Management Solution</td>
			<td>https://arctosdb.org</td>
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			<td>Disposible Nitrile Gloves</td>
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			<td>Double-Ended Dental Explorer/Probe, #2 Handle</td>
			<td>Hu Friedy</td>
			<td>541-5860</td>
			<td></td>
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			<td>High resolution digital camera</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
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			<td>Light source</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Magnifying glass (Optional)</td>
			<td></td>
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			<td>Surgical Magnification Loupes (Optional)</td>
			<td>Surgitel</td>
			<td>EVC00TTL</td>
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</table>

systematic assessment of mammalian skull specimens for dental and temporomandibular joint pathology

Museum skull specimens represent a non-invasive, informative, and readily available means to study temporomandibular joint (TMJ) lesions, dental pathology, and anatomic variations in many mammalian species. Studying the teeth and jaws of an array of species can present a challenge requiring attention to detail and understanding of a species&#39; normal anatomy. In the present article, a systematic and precise protocol for examining skull specimens is discussed that has been applied to a variety of mammals to define characteristic diseases in the oromaxillofacial region. The procedure outlined is simultaneously precise, repeatable, and adaptable to the highly differing skull and tooth shapes and anatomy across species. Specifically, specimens are examined for missing teeth, periodontal disease, endodontal disease, TMJ pathology, and anatomical variations. Results gleaned from research on museum specimens may reflect the natural history, health, and disease status of individuals and species. Furthermore, these data can inform ecological and conservation research efforts, as well as the care of captive individuals.

The current protocol results in a combination of objective and semi-subjective data, and the positive outcome depends on the accurate and repeatable assessment of specimens. Multiple observers with knowledge of the normal anatomy of the target species and an understanding of general dental and maxillofacial pathology ideally must be present to assess each specimen to minimize bias systematically. The assessment of each specimen must be discussed, and a consensus needs to be obtained. No threshold for the number of specim...

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Systematic Assessment of Mammalian Skull Specimens for Dental and Temporomandibular Joint Pathology

The present protocol describes the techniques for the systematic assessment of skull specimens to characterize anatomical and developmental variations and abnormalities of the teeth, periodontal disease, endodontal disease, and temporomandibular joint pathology.

Museum skull specimens represent a non-invasive, informative, and readily available means to study temporomandibular joint (TMJ) lesions, dental ...

We have collaborated with the California Academy of Sciences and other museums for quite a while now to document the dental pathology of mammals of the western United States, including the bears, the marine mammals, the felids, and the canids, and the advantage of this technique that it allows for reproducible results across the species. Our protocol is an excellent means of enacting the scientific method. Past projects have been formative for veterinary students and pre-dental students, and collaborators have developed an understanding of normal maxillofacial anatomy, data analysis, and scientific writing.The temporomandibular joint, or TMJ, is one of the most important joints of the body of mammals, as it affects breathing, eating, drinking, and other functions like protection. Information obtained from study of the TMJ and its disorders is crucial for conservational science, since it affects survival and fitness This protocol can provide insight into companion animal and exotic animal health, evolutionary biology, and ecology. This method is specific to the oral maxillofacial region of mammalian species.The prerequisites for using this methodology are to have a good understanding of the normal anatomy of the species and to have a good working knowledge of dental pathology in general to recognize the lesions. Document the specimen information, including identification numbers, species, sex, and location of origin. Examine the skull for completeness of the anatomic structures.Estimate the age of the specimen at the time of death based on the closure of cranial sutures. For the gray fox skull, young adults have open sutures at the base of the skull, while the sutures of older adults have closed. Consult pertinent literature for the time of cranial suture closure, as this varies for each target species.Replace loose teeth with their corresponding alveolae. Inspect each dental quadrant successionally, and record the presence or absence of teeth. Classify the loss of each tooth as either congenitally absent or acquired tooth loss or artifactually absent.Document any persistent deciduous teeth or supernumerary teeth. Examine the shape of the crown of each tooth and any visible root structure. Document the number of roots by examining the loose teeth out of their alveolae.Examine the teeth for any extra roots. Use a metal or plastic periodontal probe and explorer to ascertain the texture of the alveolar bone for evidence of periodontitis. Attempt to insert the periodontal probe between the roots of each multi-rooted tooth to test for the presence of furcation involvement or exposure.Depending on the number of roots, multiple areas should be tested for furcation. Examine each tooth for fracture as indicated by the loss of tooth substance with sharp edges. To determine if each fracture is complicated or uncomplicated, attempt to insert the probe into the pulp chamber from the fractured site.Examine both sides of the skull and the teeth for evidence of periapical lesions that are characterized by expansion of the alveolar bone in the region of the apex of the tooth root with evidence of increased vascularization. Examine each tooth for attrition or abrasion indicated by the loss of tooth substance with a smooth, glassy appearance and rounded edges. Attempt to insert the explorer tip into the pulp chamber to determine pulp chamber exposure from the abraded region.Inspect the bone components of the temporomandibular joint, including the head of the mandible, the condylar process, and the mandibular fossa of the squamous temporal bone. Check for evidence of temporomandibular joint pathology, while ruling out artifacts such as postmortem trauma, drawer damage, or preparation artifacts. Next, examine the skull for evidence of traumatic injury.The current protocol results in a combination of objective and semi-subjective data, and the outcome depends on the accurate and repeatable assessment of specimens;for example, in Mirounga angustirostris, persistent deciduous teeth were observed, and supernumerary root was seen in Lynx rufus californicus. In Urocyon cinereoargenteus, stage two periodontitis was observed, characterized by increased vascularization of the alveolar bone. Stage three was characterized by moderate bone loss and furcation involvement.Stage four was characterized by severe alveolar bone loss. Fractured teeth were observed in Callorhinus ursinus and periapical lesions in Enhydra lutris nereis. Temporomandibular joint osteoarthritis was observed in Puma concolor cougar with an irregular articular surface, subchondral bone exposure, and porosity of the mandibular condylar processes.A specimen free of any detectable pathology or minimal disease or anatomic variation was found and documented to act as a standard for comparison. The most important aspects of this protocol are familiarity with a species'normal maxillofacial and dental anatomy, recognition of affected tissues, and diligent documentation of findings. Future studies of the TMJ will provide information on histology, biomechanics, and also observation of the animal in the wild.This will put context of the pathology found in the museum specimen. Our work has provided a sound methodology for analysis and has yielded important reference points for comparative work with other species in other parts of the world.

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