The Hyrax as A Model for Facial Biomechanics and Growth

St. Claire, Marisa

Abstract

This proposal will explore the utility and feasibility of the rock hyrax (Procavia capensis) as a laboratory model for aspects of facial biomechanics and growth relevant to the etiology and prevention of dental crowding and malocclusion. Dental crowding (especially third molar impactions) and certain malocclusions partially result from inadequate mechanical stimuli to the mandibular and maxillary arches during growth. However, the magnitude, frequency and orientation of forces requisite for normal growth are unknown. Hyraxes may be a uniquely suitable model for studying the effects of biomechanical forces on human facial growth. As in humans, the entire postcanine tooth row in hyraxes lies beneath the orbits, so that postcanine occlusal forces are probably not counteracted by a rostrum. Hyraxes also resemble humans in having low-crowned teeth, and a transverse chewing stroke with buccal and lingual phases. This Phase I study will: (1) test protocols for laboratory management of hyraxes and their amenability to experimental manipulation; (2) begin a breeding colony; (3) conduct preliminary studies of hyrax facial and masticatory biomechanics using strain gauge, electromyogram and finite element analyses; and (4) conduct a preliminary study of site-specific reaction norms of facial growth in response to variations in masticatory loading forces.

Proposed Commercial Applications

The commercial value of the project is to develop an improved in vivo animal model for evaluating the biomechanical effects of growth responses to masticatory forces in the human face. Such an animal model will be useful for research and development of corrective procedures and devices for applying appropriate mechanical stimuli to treat and/or prevent orthodontic diseases such as malocclusions dental crowding. An improved animal model will also be useful for applied and clinical research on the biomechanical and growth effects of various foods and diets.