Dentine production using data from decayed and sound teeth
Research type
Research Study
Full title
Linking Dental Pulp elastic moduli, RNA and histology
IRAS ID
294171
Contact name
Laura Whitehouse
Contact email
Sponsor organisation
University of Leeds
Duration of Study in the UK
1 years, 0 months, 0 days
Research summary
Summary of Research
It is known that the stiffness of tissue affects how stem cells change (differentiate) and move (migrate).
We hypothesize that in carious (decayed) teeth, the dental pulp (the soft tissue at the middle of a tooth, which contains the nerves and vessels that keep a tooth alive) becomes stiffer to encourage stem cells in the pulp to migrate to areas of decay and change into dentine-producing cells. This is part of a process called ‘reparative dentine formation’ where the normal cells responsible for keeping the dentine alive have been killed by the decay and the newly differentiated cells replace them. These new cells make reparative dentine as part of a ‘wound healing’ response to protect the pulp from the decay. Frequently this process is ineffective at sealing the pulp and an extraction or root canal treatment is indicated.
To explore reparative dentine formation, we will look at the stiffness of the dental pulp in decayed and sound teeth. To do this, we will use; atomic force microscopy (AFM) (a special type of microscopy that probes the tissue) to look at the tissue stiffness, tissue sections and special stains (immunohistochemistry) to look at what cells are present and what they are differentiating to and RNA data to explore cellular signalling.
We require sound and carious teeth to provide a comparison between normal and the diseased state. Carious teeth are frequently extracted because of decay, sound teeth are extracted because of orthodontic reasons or due to impaction or advanced gum disease.
Preliminary work, using teeth from Leeds Skeletal Tissue Bank, has shown that there is a difference in stiffness between the decayed and sound teeth. However, it usually takes >24 hours for teeth to be transported and processed by the Tissue Bank, causing much RNA depletion, making RNA analysis impossible.
Summary of ResultsThe study aimed to understand the differences between decayed and sound teeth.
Sometimes in decayed teeth, stem cells within the pulp (the soft part in the centre of the tooth containing blood vessels and nerves) begin to produce dentine to protect the pulp from the decay.
We examined this process using extracted teeth to better understand the factors involved in making dentine, so that we can create a new filling material that can regrow dentine from within the tooth.
This study looked at the fibres that make up the tissue of the pulp, assessed the stiffness of the tissue and cell-signalling.
We found that the stiffness of the pulp reduces towards the middle of the pulp and that the number of pulp fibres, the width of the fibres and the alignment of the fibres also reduced. This is important because stem cells in the pulp are thought to live near the middle of the pulp, and better understanding how these cells function in their environment helps us to better understand how they can be used to rebuild broken tooth tissue.
We also found that decayed teeth showed fewer areas of difference in their stiffness across the pulp than sound teeth. This is also important as the stem cells within the tooth are thought to travel to areas of damage in an attempt to heal the tooth; if we can work out what makes this process easier and quicker, we can build better materials for tooth repair.
We linked these findings to cell-signalling (RNA) data. We found that genes linked to inflammation and tissue regrowth are more commonly found in decayed teeth than sound.
It is possible that the inflammation and tissue changes could be making it easier for stem cells to travel to the area of tooth damage and transform into hard-tissue making cells (called odontoblasts) that can heal the tooth.
The new data and information from this study was used to help inform the characteristics needed to make a gel capable of producing dental hard tissues.
REC name
North West - Greater Manchester East Research Ethics Committee
REC reference
21/NW/0106
Date of REC Opinion
25 Mar 2021
REC opinion
Favourable Opinion