Disputas: Elisabeth Aurstad Riksen
Cand.odont. Elisabeth Aurstad Riksen ved IKO vil forsvare sin avhandling for graden ph.d: Effects of epigenetic and environmental factors on biomineralization
Tid og sted for prøveforelesning
- Professor Erik Fink Eriksen, UiO
- Ph.D. dr. odont Ann-Marie Roos-Jansåker, Universitetet i Kristianstad/ Centrum för specialisttandvård, Kristianstad
- Post-doc dr.odont. Else Kristine Breivik Hals, UiO
Leder av disputas
Instituttleder, professor Pål Barkvoll
For mer informasjon
Ta kontakt med Knut Gythfeldt
Effects of epigenetic and environmental factors on biomineralization.
Biomineralization is a complex process involving multistep series of up-and down
regulation of gene expression and activation of a cascade of growth factors ultimately
leading to mineralization of an organic matrix. Bone tissue is continuously remodelled
throughout life and secondary reactive dentin might be formed by odontoblasts in the
dental pulp; whereas tooth enamel is without the ability to regenerate or recover after
tissue damage. Once enamel is formed it loses its contact with the enamel matrix
secreting cells, the ameloblasts.
The main objective of this dissertation is to investigate if the enamel proteins amelogenin
and ameloblastin have epigenetic effect on osteoblast gene expression and bone growth
factors, and how enamel protein gene expressions are influenced by environmental
factors like fluoride and fluoxetine, a selective serotonin reuptake inhibitor (SSRIs).
The experimental methods include both in vivo and in vitro tests at a defined time frame
and environmental conditions. Cells, cell culture medium, and tissue are analyzed using
a range of methods including PCR, ELISA, Luminex, dot plot and spectrophotometry.
Recombinant amelogenin and enamel matrix derivative stimulates osteoblasts on
titanium in vivo and in vitro, whereas purified fractions of amelogenins of similar size
have unique effects on proliferation and differentiation of osteoblasts in vitro. Fluoride
reduces the gene expression and secretion of vascular factors in cultured ameloblasts.
Both murine enamel organs and ameloblasts have functional serotonin receptors. The
gene expression of enamel proteins and vascular factors are reduced in a dose-
dependent manner by fluoxetine, and serotonin. Conclusively enamel proteins stimulate
osteoblasts in vivo and in vitro, ameloblasts have serotonin receptors, and both fluoride
and SSRIs have adverse effect on enamel protein gene expression and vascular factors
contributing to development of enamel defects.