Oral ecology

The Department of Dentistry at Health has been studying the biofilm of human teeth for more than three decades. This makes the department an international pioneer in its field, and we possess profound and extensive knowledge about the life of bacteria on dental surfaces.

Our research group seeks to answer many questions, including:

  • Which biological mechanisms underlie the generally peaceful relationship between us and the microflora in our mouths?
  • Which changes in the composition of dental plaque (biofilm) can explain the development of periodontal disease?
  • How do various environmental factors affect the composition and structure of the dental biofilm and its potential for producing acid?
  • How can our scientific findings be converted into new strategies for preventing dental caries and periodontal disease?

Dental biofilm. Courtesy of Skaaring, Fejerskov & Nyvad. Aarhus University.The aim of doing research in oral ecology is to expand and diversify our knowledge about the oral microflora, and about its interaction with saliva, diet, and the immune system. By increasing our knowledge in these areas we become more able to understand what causes dental diseases, and more qualified to suggest how best to prevent them from occurring. Our basic working hypothesis is that caries and periodontal disease are caused by changes in the oral environment. If the mouth is supplied with sugar, its environment will favour acid-producing bacteria, which leads to cavities. If bacterial build-up is allowed to proceed along the gums, this leads to gingivitis, which can ultimately develop into periodontal disease.

Ecological imbalances lead to disease
One of the questions our research explores is how the composition, structure, and metabolic processes in plaque can explain why some people are more prone to develop pathological conditions than others. In short, we regard dental disease as the result of an imbalance in oral ecology – an imbalance that can be rectified, provided we intervene at an early stage, before it manifests as cavities or loosening of the teeth.


Research in oral ecology is conducted in close collaboration with other groups, both in Denmark and from the international research community.

1. ProSurf. One noteworthy project is our interdisciplinary cooperation with AU SCIENCE AND TECHNOLOGY (iNANO ) and industrial partners on a platform called “ProSurf – proteins and nanotechnology”. The objective of ProSurf is to develop nanoparticles based on milk protein for
use in dental-hygiene products. ProSurf is partly funded by the National Danish Advanced Technology Foundation.

Other ongoing projects are:

2. Studies of the structural composition and metabolic potential of young dental biofilms studied in vivo, with and without influence from sucrose.
3. Investigations to explain why certain periodontal-disease bacteria evade the effect of high antibody concentrations that they themselves generate in the host.
4. Investigation of the biochemical mechanisms by which toxins from periodontal-disease bacteria can kill our immune cells.


Actinomyces naeslundii in initial dental biofilm formation
(Dige I. Microbiology. 2009;155:2116–26)

pH landscapes in a novel five-species model of early dental biofilm
(Schlafer S. PLoS One. 2011;6(9):e25299. Epub 2011 Sept 23)

The role of bacteria in the caries process: Ecological perspectives
(Takahashi N. J Dent Res. 2011;90:294–303)

IgA and mucosal homeostasis
(Reinholdt J. In: Morteau O, editor. Oral Tolerance: The response of the intestinal mucosa to dietary antigens. Plenum Publishers, 2004, New York, pp. 81–98)

Microbiological and immunological characteristics of young Moroccan patients with aggressive periodontitis with and without detectable Aggregatibacter actinomycetemcomitans JP2 infection
(Rylev M. Mol Oral Microbiol. 2011;26:35–51)


In recent years, molecular and microscopic methods using fluorescent biomarkers have made it possible to analyse the bacterial composition and pH of intact biofilms without removing them from the tooth. This means that we can now examine the biofilm in its natural surroundings, along with the surface on which it grows and in interaction with the local environment in the oral cavity. Such methods are employed today to study whether various types of “environmental therapy” using nanoparticles are able to inhibit the potential of the biofilm to generate pathological conditions.

We use the following analytical methods:

  • DNA sequencing
  • Metabolomics
  • Immunochemistry/immunocytochemistry
  • FISH (Fluorescence In Situ Hybridization)
  • Biofilm pH real-time imaging
  • CLSM (Confocal Laser Scanning Microscopy)
  • SE M (Scanning Electron Microscopy)
  • Microradiography
  • Flow-cell experiments
  • In situ experiments.


Bente Nyvad

Phone: +4587168095

Golnoush Bahrami Møller
Associate professor

Phone: +4587168148

Vibeke Bælum

Phone: +4587167975

Dorte Haubek

Phone: +4587168092

Lise-Lotte Kirkevang
Associate professor

Phone: +4587168101

Rodrigo Lopez

Phone: +4587168112