New approach to quantifying developmental variation in the dentition using serial microtomographic imaging

Abstract

KEY WORDSserial microtomographic imaging; tooth development; deciduous molar ABSTRACT Dental morphogenesis and cellular differentiation are expressed in the fully formed tooth by the topography of the dentin-enamel junction and outer enamel surface. These boundaries can be differentiated using a variety of imaging systems. In this study, we used serial microCT imaging to provide accurate 3D reconstructions of developing lower human second deciduous molars. These were used to quantify the volume of enamel and dentin of individual cusps in relation to basal crown height. As growth and differentiation proceed apically, the spatial orientation of cusp tips and their bases were used to estimate their order of initiation and coalescence. We found that the order of coalescence differed from the order of initiation. We also found that dentin cusp height and volume as well as rate and quantity of enamel apposition varied along mesio-distal and bucco-lingual axes, and were independent of order of initiation and duration of growth. These results demonstrate that the potential for variation in crown size and form is maintained throughout development. We propose that the microCT model developed in this study constitutes a new approach for the investigation of developmental variation and its contribution to phylogenetic variation expressed in crown form and size.

New visions of dental tissue research: Tooth development, chemistry, and structure

“…This interface represents the initial position of the cells that are responsible for enamel and dentine secretion and is believed to be heavily influenced by embryological enamel knots that form before hard-tissue secretion (reviewed in Avishai and colleagues 93 and Skinner and colleagues 94 ). Olejniczak and colleagues, 85,[95][96][97] have demonstrated that the primate EDJ has a taxon-specific shape, despite some intra-taxon variation, and that components of this shape, such as relative dentine horn height, may serve to group members of the Ponginae.…”

Assessment of the accuracy of dental enamel thickness measurements using microfocal X‐ray computed tomography

“…A number of studies have examined the repeatability of measurements (and inter-and intraindividual errors in locating landmarks) from mCT images of trabecular bone (e.g., Durand and Rü egsegger, 1991;Balto et al, 2000), tooth root canals (Peters et al, 2000), and tooth enamel (Avishai et al, 2004). To date, however, the only studies that have attempted to assess the accuracy of measurements derived from high-resolution X-ray computed tomography have been conducted with reference to trabecular bone configuration (Kuhn et al, 1990;Mü ller et al, 1996aMü ller et al, ,b, 1998Hildebrand et al, 1999;Fajardo et al, 2002), periapical and periradicular alveolar bone destruction (Balto et al, 2000;von Stechow et al, 2003), the diameters of tooth root canals (Rhodes et al, 1999), and cortical bone porosity (Cooper et al, 2004).…”

“…McErlain et al (2004) examined a single tooth from a 420-year-old Late Iron Age site in Cambodia and simply commented that they were clearly able to differentiate visually the hard tissue components, which were displayed with "exceptional clarity." The study by Avishai et al (2004) examined individual error rates in locating landmarks (and resultant measurements) in a series of tooth germs derived from archeological contexts.…”

Mineral distribution in highly fluorotic and in normal teeth: A synchrotron microcomputer tomographic study

“…Rat incisors were studied by Wong et al with a special emphasis on the dentin-enamel junction [20]. Developing human molars were studied by Avishai et al [21]. We have studied the pharyngeal teeth of zebrafish [22].…”