Condition category
Oral Health
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Neutrophils are the most common type of white blood cell found in the body. They enter the mouth mostly through the small open space of the gums, surrounding the teeth. These are also known as gingival crevices. Little is known about these oral neutrophils functional potential (what they can do) and their possible contribution in the maintenance of oral health. This study aims to investigate the presence and functional capabilities of oral neutrophils in people with no teeth (edentulous) since these individuals lack the presence of the gingival crevices found in people that still have their teeth.

What does the study involve?
This study looks at neutrophils taken from people without teeth but with a healthy mouth (orally healthy) with orally healthy people with teeth (dentate). Rinse and blood samples are taken from each person and analysed for functional activity (that is, ti see what functions the neutrophils have in the mouth) on the same day. All participants are informed about the purpose of the study, are given written information and are asked for their written consent prior to the start of the study.

What are the possible benefits and risks of participating?
This observational study gives new insights in the functioning of the immune response within the mouth of people without teeth. No risks or symptoms are to be expected to occur due to participating in this study.

Where is the study run from?
Academic Centre for Dentistry Amsterdam (Netherlands)

When is the study starting and how long is it expected to run for?
May 2014 to January 2016

Who is funding the study?
University of Amsterdam (Netherlands)

Who is the main contact?
Dr Elena Nicu

Trial website

Contact information



Primary contact

Dr Elena Nicu


Contact details

Gustav Mahlerlaan 3004
1081 LA
1081 LA

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Impaired polymorphonuclear neutrophils in the oral cavity of edentulous subjects


Study hypothesis

Edentulous subjects present with less functional polymorphonuclear neutrophils compared to dentate subjects.

Ethics approval


Study design

Observational case-control study

Primary study design


Secondary study design

Case-control study

Trial setting


Trial type


Patient information sheet


Edentulous subjects wearing full dentures for a minimum period of 1 year.


Volunteers were recruited at the Academic Centre for Dentistry Amsterdam (ACTA) in the Netherlands. Subjects were either patients at the dental clinics or non-professional personnel. All subjects were screened for their periodontal condition and additionally dental radiographs were taken in order to confirm the absence of alveolar bone loss. Edentulous subjects were included if they have been wearing a full denture for a minimum period of 1 year.

All subjects were informed about the purpose of the study, received written information and had given written consent prior to the start of this study. Each subject was asked to donate one blood sample and 4x oral rinse samples. Samples were donated on the same day. Venous blood samples were drawn from the antecubital fossa into one 9 ml sodium heparin blood collection tube. Oral rinse samples were taken before any other intra-oral procedures were carried out in order to avoid contamination. The edentulous subjects were asked to remove their dentures before the supervised sample collection. All subjects were instructed not to gargle nor clear their throat during the sampling procedure. Four serial rinses of the oral cavity were obtained with 10 ml of sterile sodium chloride solution (0.9%) for 30 seconds, each with 4.5 min intermission. The rinse samples were pooled into one collection tube.

Neutrophil counts were determined in blood and from oral rinses. Additionally cell functionality was determined using flow cytometry (cell membrane integrity, cell activation status and reactive oxygen species).

Intervention type



Drug names

Primary outcome measures

The presence of functionally impaired neutrophils in the oral cavity of edentulous subjects, measured using flow cytometry directly after sampling. All samples were analyzed using flow cytometry on the same day.

Secondary outcome measures

1. Cell number count, using a Muse cell counting device.
2. Cell membrane integrity, analysed using propidium iodide staining.
3. Neutrophil expression of cell activation markers CD11b, CD63 and CD66b and corrected for non-specific binding of isotype control antibodies.
4. Presence of constitutive reactive oxygen species (ROS) production, detected using dihydrorhodamine 123.
5. Presence of ROS production in response to stimulation, determined in samples incubated with forbid myristate acetate (PMA) or Fusobacterium nucleatum

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

edentulous for a minimum period of 1 year wearing a full denture OR dentate subjects with a minimum of 20 teeth.

Participant type


Age group




Target number of participants


Participant exclusion criteria

conditions that are known to systemically affect the neutrophil functionality (such as Diabetes, hematological disorders, recent illness, allergies). Furthermore, antbiotics use, pregnancy, removal partial dentures, night guards, orthodontic banding, oral piercings, oral lesions were excluded.

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Academic Centre for Dentistry Amsterdam (ACTA)
Gustav Mahlerlaan 3004
1081 LA

Sponsor information


Academic Centre for Dentistry Amsterdam (ACTA)

Sponsor details

Gustav Mahlerlaan 3004
1081 LA

Sponsor type




Funder type


Funder name

Universiteit van Amsterdam

Alternative name(s)

University of Amsterdam, UvA

Funding Body Type

private sector organisation

Funding Body Subtype




Results and Publications

Publication and dissemination plan

Intention to publish date

Participant level data

Available on request

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes