Ole Blok Fejerskov

Diagrammatic model of the enamel organ during maturation stage of amelogenesis stating the localization of proven ion transporters (coloured circles). The ameloblasts cyclically change between ruffle-ended (RA) and smooth-ended (SA) ameloblasts. The present model assumes that ameloblasts and papillary cells (PL) act as a functional syncytium allowing free diffusion of ions via the numerous connected gap junctions. Further it suggests, that carbonic anhydrase (CA II) together with vacuolar H+-ATPase, AE2 and an unidentified Cl- channel are key players in the acidification of the enamel surface compartment (ES) in the RA stage. In SA cells, internalization of the H+-ATPase from the distal cell surface membrane precludes this acidification and the intercellular spaces between SA cells open towards the enamel surface. This allows acidified, decomposed enamel matrix proteins (DEMP) to escape from the bulk enamel and let the HCO3- containing intercellular fluid neutralize the enamel surface. AE2 and the Na+/H+ exchanger (NHE1) may in the SA cells function to regulate intracellular pH and cell volume, which may both be challenged by the rapidly changing intercellular milieu. In our view, the Na+-K+ ATPase activity in the papillary layer maintains negative cell potential and electrochemical Na+-gradient, during all stages of the ameloblast modulation cycle, and the presence of a range of membrane proteins specialized for HCO3--transport in the papillary is a reflection of the cells capacity to defend pHi in a changing extracellular environment. bl, basal lamina; K+, ubiquitous potassium channel.

Group Leader

Ole Blok Fejerskov
Professor, Ph.D, Dr.Odont, Emeritus
More information

RESEARCH

Experimental animal studies on enamel formation under  normal and pathophysiological conditions

RESEARCH INTERESTS
The effect of fluoride on dental enamel during development ( dental fluorosis).

Human enamel pathology.

The natural history of  dental caries and periodontal diseases.

Cell membrane ion transporters.

Compartmental pH regulation extracellularly.

METHODOLOGIES
Immuno-histochemistry,  electron microscopy,

Clinical and epidemiological studies in Africa, Thailand and China combined with microbiological studies of oral ecology.

Collaborators & Centers

  • “Membranes” – an  AU interdisciplinary research center
  • Prof. Yoshiro Takano, Section of Biostructural Science, Graduate School of Tokyo Medical and Dental University
  • Prof. Gunnar Dahlén, Dept. of Oral Microbiology, Göteborg University
  • Prof. Vibeke Baelum, Dept. of Public Health, AU
Henvendelse om denne sides indhold: 
Revideret 03.08.2016