Developmental Defects of the Root

There are numerous hereditary conditions that can affect the shape, size, and composition of the dental roots. Many syndromes and chromosomal anomalies have associated tooth and dental root phenotypes. Therefore, the following section is not meant to be an exhaustive review but rather will highlight some of the critical components for root formation discussed in the previous section. There are many diverse conditions that are associated with taurodontism Online Mendelian Inheritance in Man...

Evolution and Genetics of Teeth

Completion of the human genome project vastly improved our ability to discern the genetic etiologies of inherited diseases. Besides the human genome, partial and complete characterization of other genomes is progressing at a steady pace and already huge sequence databases are available from numerous organisms. Clever analyses of these databases have yielded surprising and interesting insights into the evolution of vertebrate mineralized tissues. This special issue of Cells Tissue and Organs...

Classification Of Taurodontism

CYNODONT HYPODONT MESODONT HYPERDONT PYRAMIDAL CYNODONT HYPODONT MESODONT HYPERDONT PYRAMIDAL < 1.10 1.10 - 1.29 1.30 - 2.00 > 2.00 < 1.10 1.10 - 1.29 1.30 - 2.00 > 2.00 Fig. 1. Taurodontism ranges in severity, becoming increasingly severe with increasing delay of invagination of the epithelial root sheath. The degree of taurodontism can be quantified based on the crown-body (CB) to root (R) ratio. each have a supernumerary root variant (three roots as opposed to the more typical two...

Clinical Implications

Normal formation of the dental root is critical to the function and longevity of the dental apparatus. Variable root formation results in numerous developmental variants that can challenge virtually every aspect of dental therapy. The loss of or a decrease in root structure compromises the support of the clinical crown (decreased crown to root ratio) and will likely result in decreased tooth longevity Grossmann and Sadan, 2005 . The diverse morphology of the dental roots, multiple supernumerary...

AMEL and the Evolutionary Origin of EMP Genes

The current knowledge on the relationships and evolutionary origin of EMPs was acquired in several steps, and this study represents the last (but not least) one. This story can be briefly reconstructed as follows. In 2001, Delgado et al. showed a high sequence similarity of the 5' region (exon 2, which mainly encodes the signal peptide) of AMEL, SPARC, and SPARCL1, suggestive of a common origin of this region after duplication. Using a molecular-clock method to estimate SPARC SPARCL1...

Enamel Enameloid and the Origin of EMPs

Morphological studies of enamel and enameloid in living taxa have shown that they are different in their mode of formation. The enamel organic matrix is secreted by the ameloblasts, and contains enamel-specific proteins. In contrast, enameloid organic matrix is mostly deposited by odontoblasts and contains a large amount of collagen, but the ameloblasts contribute to its formation, too Prostak and Skobe, 1984 Sasagawa, 1984 Prostak and Skobe, 1988 Prostak et al., 1993 Sasagawa, 1995, 2002 ....

Results and Discussion

SCPP Genes of Placentals, Marsupials, and Different lineages of placental mammals have distinct duplication and deletion histories of milk and saliva class SCPP genes. For instance, humans have three functional casein genes CSN1S1, CSN2, and CSN3 , whereas the mouse has five Csn1s1, Csn2, Csn1s2a, Csn1s2b, and Csn3 Rijnkels et al., 2003 . CSN1S2 became a pseudogene in the human, chimpanzee, and rhesus monkey genomes. Exon duplication and deletion also occur frequently in casein genes. In...