ORIGINAL ARTICLE Micro-CT assessment of changes in the morphology and position of the immature mandibular canal during early growth E. F. Hutchinson 1 • G. Florentino 1 • J. Hoffman 2 • B. Kramer 1 Received: 1 February 2016 / Accepted: 9 May 2016 Ó Springer-Verlag France 2016 Abstract Purpose The mandibular canal contributes to the devel- opment and growth of the mandible, as it acts as a conduit for the growing inferior alveolar neurovascular structures. A clear understanding of the canal’s pathway is, therefore, important in interpreting the growth pattern of the inferior alveolar neurovascular bundle. This study investigated the position of the mandibular canal within the body of the mandible and its general dimensions within a pediatric collection of mandibles. Methods The sample included 45 mandibles and was subdivided into three: group 1 (30 gestational weeks to birth), group 2 (birth to 12 months), and group 3 (1 to 4 years). Mandibles were scanned using a Nikon XTH 225L micro-CT unit. Scanning conditions ranged between 85 kV/83 lA and 100 kV/100 lA. Measurements inclu- ded: the maximum width and height of the mandibular canal and distances between the mandibular canal and the relevant surfaces of the mandible. Data analysis included an ANOVA, MANOVA, and principal component analysis. Results The mandibular canal increased significantly in size from 30 gestational weeks to 12 months relative to the deciduous molar crypts. Postnatally, the mandibular canal increased significantly in height at the level of the second deciduous molar crypt. The canal lies closer to the buccal surface in the region of the first and second deciduous molar teeth. Conclusion The consistency in the positioning of the mandibular canal within the body of the mandible may assist in predicting the occurrence of aberrant growth pat- terns, particularly during the initial stages of growth. Keywords Mandibular canal Á Development Á Micro-CT Á Dentition Introduction During the late prenatal and early postnatal periods, the craniofacial skeleton is subject to a variety of complex functional relationships that are associated with the early stages of mastication [9, 10]. These relationships and their subsequent effect on the morphology of the craniofacial skeleton are of importance in understanding the growth of the mandible [10, 16]. Both the ‘‘functional matrix model’’ [23–25] and the ‘‘principle of archial growth’’ [27] are of value in explaining the adaptation of the mandible to its functional demands. In the functional matrix model, the mandible consists of several subcomponents that are functionally influenced by either the dentition or a soft-tissue structure, e.g., the muscles of mastication [23, 24]. While changes in the morphology of each of the components may be due to the functional demands of an associated soft tissue structure, collectively, all the components of the mandible contribute to its growth as a functional unit [23–25]. The ‘‘functional matrix model’’ was further expanded by the ‘‘principle of archial growth’’ [27], which suggested that the human mandible grows by means of vertical (superior–anterior) apposition at the ramus along a pathway demarcated by & E. F. Hutchinson Erin.hutchinson@wits.ac.za 1 School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa 2 Department of Radiation Sciences, South African Nuclear Energy Corporation, Pelindaba, South Africa 123 Surg Radiol Anat DOI 10.1007/s00276-016-1694-x