Method to identify bioburden in a root canal following preparation

The Problem

Bacteria remaining in the root canal (RC) space at the time of completion of a root canal treatment (RCT) can lead to a persistent or secondary infection, which requires revision of the treatment. Currently, there are no methods in widespread use to detect bacterial presence within the root canal space in a fast and reliable manner.  Such methods are especially relevant in determining the endpoint in root canal treatments to improve the success rates and the longevity of the treatment in preserving the tooth.


The Solution

A new optically-based spectroscopic technique has been developed which allows the rapid detection of live-organisms within root canals, without signal from dead or non-viable cells complicating the readout.  Patients would immediately benefit from this novel technique since the absence of significant bacterial contamination from root canals increases the success rate of root canal treatments.  It will also allow the reduction of the number of visits necessary to complete the endodontic treatments by reducing the need for temporary repairs during intermediate medication with antibacterial agents.  Two test formats are proposed, micro-endoscopic in situ visualisation or a bench-side evaluation of the paper points already in use by practitioners for cleaning/drying of the excavated root canal.

Technology has been developed for the determination of live cellular organisms using a photo-luminescence method in vivo in root canals or on paper points. A known fluorophor is used which binds to the live cell and is converted from a photo-luminescently inactive form to an active form, following a short period of incubation (an example is Calcein AM; which is already widely used).  Either the probe is inserted into the cavity of the tooth and any luminescence measured to determine whether any viable cellular material remains in situ, or a sample of material can be extracted on a paper point and the luminescence determined ex vivo.

In commercial form this system would involve a patient-side reader and a reagent system to prepare the points for bio-burden detection, with adaptions made for in vivo and ex vivo measurement. 


Benefits and Applications

Approximately 14M RCT’s are carried out in England and Wales per annum, yet initial endodontic treatment still fails in up to 25 % of cases, commonly as a result of residual infection.  The application of this approach is anticipated to increase the success rate of endodontic therapy.  In addition, it is anticipated that use of this technology will enable tooth preservation to be achieved despite a reduced number of procedures by enabling full restoration of an affected tooth within a single treatment session.

For in vivo visualisation of residual biofilm, current micro-endoscopes provide only white light visualisation of the root canal, which is of limited value in assessing the effectiveness of the preparation.  This technology would significantly extend the performance and value of current equipment, providing a clinically valuable assessment not currently available.  The optical detection of residual biofilm within root canal spaces has been benchmarked to the gold-standard microbiological culturing technique and preliminary data have been obtained in vitro establishing the validity of the approach. 

Because paper points are routinely used in the root canal process, an ex vivo system to evaluate the burden would integrate readily into existing treatment practice. The test can be run in parallel to other work in the root canal treatment.

Both approaches would be of major benefit in indicating accurate end points of the RC drilling and cleaning step, removing the uncertainty associated with visualising the inside of the roots, which results either in residual material remaining or for which practitioners compensate by over-drilling resulting in unnecessary tooth damage.


IP Position

A patent application was filed with priority date 17 AUG 2011 and this resulted in an international PCT application (published as WO 2013/024088) which has led to national applications pending in Europe and Japan. Notice of allowance received for USA.  Commercial development partners are sought and field specific exclusive licences are available.


Patent Information:
For Information, Contact:
Ceri Mathews
IP & Licensing Manager
King's College London
Frederic Festy
Timothy Watson
Federico Foschi
Richard Cook
Garrit Koller
Francesco Mannocci