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The ultrastructure of subgingival dental plaque, revealed by high-resolution field emission scanning electron microscopy

Lookup NU author(s): Dr Richard HollidayORCiD, Professor Philip Preshaw, Professor Nicholas JakubovicsORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Aims: To explore the ultrastructure of subgingival dental plaque using high resolution field emission scanning electron microscopy (FE-SEM) and to investigate whether extracellular DNA (eDNA) could be visualised in ex vivo samples.Methods: Ten patients were recruited who fulfilled the inclusion criteria (teeth requiring extraction with radiographic horizontal bone loss of over 50% and grade II/III mobility). In total, 12 teeth were extracted using a minimally traumatic technique. Roots were sectioned using a dental air turbine handpiece, under water cooling to produce 21 samples. Standard fixation and dehydration protocols were followed. For some samples, gold-labelled anti-DNA antibodies were applied prior to visualising biofilms by FE-SEM. Results: High resolution FE-SEMs of subgingival biofilm were obtained in 90% of the samples. The sectioning technique left dental plaque biofilms undisturbed. Copious amounts of extracellular material were observed in the plaque, which may have been eDNA since they had a similar appearance to labelled eDNA from in vitro studies. There was also evidence of membrane vesicles and open ended tubular structures. Efforts to label eDNA with immune-gold antibodies were unsuccessful and eDNA was not clearly labelled. Normal 0 false false false EN-GB X-NONE X-NONE Conclusions: High resolution FE-SEM images were obtained of undisturbed subgingival ex vivo dental plaque biofilms. Important structural features were observed including extracellular polymeric material, vesicles and unusual open tubule structures which may be remnants of lysed cells. The application of an eDNA immune-gold labelling technique, previously used successfully in in vitro samples, did not clearly identify eDNA in ex vivo samples. Further studies are needed to characterise the molecular composition of the observed extracellular matrix material.

Publication metadata

Author(s): Holliday R, Preshaw P, Bowen L, Jakubovics N

Publication type: Article

Publication status: Published

Journal: BDJ Open

Year: 2015

Volume: 1

Online publication date: 27/11/2015

Acceptance date: 22/09/2015

Date deposited: 04/12/2015

ISSN (electronic): 2056-807X

Publisher: Nature Publishing Group


DOI: 10.1038/bdjopen.2015.3


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