An odontoblast is a biological cell of neural crest origin that is part of the outer surface of the dental pulp, and whose biological function is dentinogenesis, which is the creation of dentin, the substance under the tooth enamel. The odontoblasts secrete dentin throughout life, which may be an attempt to compensate for natural wearing down of the enamel. In the case of an infection breaching the tooth to the pulp and killing odontoblasts, Periodontal Ligament Stem Cells may differentiate into odontoblasts which would then secrete reparative dentin.

Alkaline Phosphatase (ALP)

• an early marker of odontoblast differentiation.  PMID: 15610605, PMID: 16862747

alpha 1 Type 1 Collagen (alpha I type I collagen)

• detected within the endoplasmic reticulum (ER), the Golgi (G) and secretory granules (SG) of odontoblasts. PMID: 15609627
• In odontoblasts, however, the steady state level of collagen type 1 mRNA was higher in the older coronal odontoblasts. PMID: 1508873

DMP1/DMP2 (dentin matrix protein)

• specific marker of odontoblast differentiation.  PMID: 15610605, PMID: 15221440
• an acidic phosphoprotein that has been postulated to play an important role in mineralized tissue formation. The earliest localization of DMP 1 was in the Golgi region as well as in the nucleus of differentiating odontoblasts. When mineralization spread from matrix vesicles to the surrounding matrix, DMP 1 was extracellularly detected around the mineralizing globules. In the regions of fully mineralized mantle dentin, it was present in the mineralized regions, mainly around the peritubular dentin. The appearance of DMP 1 during early dentinogenesis implies a direct role for this protein in both odontoblast differentiation and matrix mineralization. PMID: 16049693
• DMP1 is localized in the nucleus during early differentiation of odontoblasts. PMID: 16679514

DPP (dentine phosphoprotein)

• synthesized by the odontoblasts, transported through their processes and secreted into the dentine. PMID: 3518674
• exclusively synthesized by odontoblasts; DPP thus can be regarded as specific biochemical markers for odontoblast activity. PMID: 2689085
• the major non-collagenous protein component of the dentin extracellular matrix. This highly acidic phosphorylated protein is solely expressed by ectomesenchymal-derived odontoblast cells of the tooth organ. PMID: 1508875

DSP (dentin sialoprotein, dentinsialoprotein)

• Dentin sialoprotein (DSP) and dentin phosphoproteins (DPP) are uniquely expressed by differentiating and fully differentiated mature odontoblasts. PMID: 9541234
• DSP and DPP are specific markers for terminally differentiated odontoblasts and are encoded by a single gene DSPP (dentin sialophosphoprotein). PMID: 15308669

DSPP (dentin sialophosphoprotein)

• specific marker of odontoblast differentiation.  PMID: 15610605, PMID: 15221440
• Dentin sialophosphoprotein (DSPP) consists of dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). The spatial-temporal expression of DSPP is largely restricted during differentiational stages of dental cells. DSPP plays a vital role in tooth development. PMID: 15980071
• a new gene involved in odontoblast differentiation. PMID: 12640735

Enamelysin

• marker of odontoblast differentiation.  PMID: 15610605
• preferentially expressed gene fragments in odontoblasts. PMID: 10980418

Mov13 allele

• a cell type and stage-specific marker for odontoblast and osteoblast differentiation. PMID: 2387241

Nestin

• a specific marker for the odontoblast. PMID: 8901197
• Reactivity for nestin could be detected in the odontoblasts, stratum intermedium and in some of the apical processes of the ameloblasts. PMID: 15721146
• a marker of young odontoblasts, is expressed in a selective manner in odontoblasts surrounding the injury site, while Notch is expressed in the sub-odontoblastic layer of cells. PMID: 12640742
• In young permanent teeth, nestin is found only in functional odontoblasts, which produce the hard tissue matrix of dentin. Expression is progressively down-regulated and nestin is absent from older permanent teeth. In carious and injured teeth, nestin expression is up-regulated in a selective manner in odontoblasts surrounding the injury site, showing a link between tissue repair competence and nestin up-regulation under pathological conditions. PMID: 10880398

OSAD (Osteoadherin)

• a keratan sulfate-containing proteoglycan, belonging to the small leucine-rich proteoglycan (SLRP) family, is highly expressed during early crown formation in the entire odontoblast cell layer, in the area of Hertwig's epithelial root sheath, in the cells of the newly formed mantle dentin, and in the odontoblasts at the fissures. Ultrastructural studies indicated that OSAD might be associated with collagen fibrils. Thus, OSAD may play an important role during tooth development and biomineralization of dentin. PMID: 12648264
• an early marker of odontoblast differentiation. In newborns, OSAD was detected at the tip of the first molar cusp where it accumulated in predentin concomitantly with odontoblast differentiation. PMID: 14673660
• In more mature teeth (newborn and 2-day-old rats), OSAD expression starts in the polarized odontoblasts and increases in the secretory and mature odontoblasts, respectively. PMID: 10913920

Osteopontin (OPN)

• expressed/localized to the root surface during cementogenesis and is also seen throughout the PDL region. The expression/localization of OPN to odontoblasts and its role in dentinogenesis is less apparent. PMID: 7785893
• OPN (osteopontin) is a bone-associated adhesion protein. OPN was expressed in the dental follicle region of molars obtained from 3 day old CD-1 mice, but was not expressed in the odontoblast layer. In contrast by day 8, positive staining was noted in the odontoblast layer, as well as in the area of Hertwig's epithelial root sheath. PMID: 1508903

Osteocalcin (OC)

• A second marker for odontoblasts, but also synthesized by osteoblasts and osteocytes. PMID: 2689085

Phex (phosphate-regulating gene with homologies to endopeptidases on X-chromosome)

• marker of odontoblast differentiation.  PMID: 15610605