About the Authors

Christopher K. Hope

chope@liv.ac.uk

Affiliations Department of Health Services Research, University of Liverpool, Liverpool, United Kingdom, School of Dentistry, University of Liverpool, Liverpool, United Kingdom

Karen Billingsley

Affiliations Department of Health Services Research, University of Liverpool, Liverpool, United Kingdom, Department of Medical Microbiology, Royal Liverpool and Broadgreen University Hospital, Liverpool, United Kingdom

Elbert de Josselin de Jong

Affiliations Department of Health Services Research, University of Liverpool, Liverpool, United Kingdom, Inspektor Research Systems BV, Amsterdam, The Netherlands

Susan M. Higham

Affiliations Department of Health Services Research, University of Liverpool, Liverpool, United Kingdom, School of Dentistry, University of Liverpool, Liverpool, United Kingdom

Competing Interests

Inspektor Research Systems BV provided the salary for author EdJdJ, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. EdJdJ’s involvement in this research was under the auspices of his status as an honourary member of staff at The University of Liverpool. The specific role of EdJdJ is articulated in the ‘author contributions’ section. This does not alter the authors' adherence to PLOS ONE policies on sharing data and materials. EdJdJ holds several patents with respect to QLF technology. The remaining authors declared no conflict of interest.

Author Contributions

Conceived and designed the experiments: CKH. Performed the experiments: CKH KB. Analyzed the data: CKH. Wrote the paper: CKH EdJdJ SMH. Discussions regarding fluorescence: EdJdJ.