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

Plain English Summary

Background and study aims
Interdental brushes help to prevent gum disease by getting rid of pieces of food and plaque from between the teeth. They have small bristled heads designed to clean between teeth and come in different widths to suit the sizes of the gaps in the teeth.
The aim of this study is to evaluate the cleaning efficacy of waist-shaped compared to straight soft interdental brushes in patients undergoing non-surgical gum (periodontal) treatment.

Who can participate?
Dental patients aged 35 years or over who require non-surgical periodontal therapy

What does the study involve?
Participants will be asked to use two different styles of interdental brushes to clean in between the teeth in either side of their mouth. They will be instructed to use the same style on the same side of their mouth for the duration of the study (8-weeks). At the start and the end of the study participants will have a full inspection of teeth and gums.

What are the possible benefits and risks of participating?
Benefits: possible improvement in gum health
Risks: None expected

Where is the study run from?
Medical University of Vienna, Austria

When is the study starting and how long is it expected to run for?
February 2017 to February 2018

Who is funding the study?
Medical University of Vienna (Medizinische Universität Wien), Austria

Who is the main contact?
Dr Christian Wehner

Trial website

Contact information



Primary contact

Mr Christian Wehner


Contact details

Sensengasse 2a
+43 650 7730390

Additional identifiers

EudraCT number

Nil known number

Nil known

Protocol/serial number


Study information

Scientific title

The influence of different interdental brush designs on the efficacy of plaque removal during non-surgical periodontal treatment: A split‐mouth randomized controlled trial


Study hypothesis

Waist-shaped interdental brushes yield better cleaning efficacy than straight designed brushes in patients undergoing periodontal therapy.

Ethics approval

Approved 27/10/2016, Ethics Committee of the Medical University of Vienna (Borschkegasse 8b/6; A-1090 Vienna, Austria;; +43 1 40 400 – 21470), ref: Nr. 1670/2016

Study design

Split-mouth randomized controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Periodontal problems


Following inclusion into the study, a periodontal status comprising whole-mouth probing pocket depths (PPD) and bleeding on probing (BOP) assessment, PCR, approximal plaque index (API), papillary bleeding index (PBI), and smoking status were evaluated (time point 1, T1). Patients received supragingival debridement and were instructed not to use further oral hygiene cleaning devices except for electric tooth brush with the same brush head, which has been given to the patients as well as to apply the same toothpaste. Initial periodontal therapy was started at the second visit (T2), and PCR, API, and PBI were assessed again. A blinded examiner determined the Plaque Index (PI) according to Silness & Loe at eight areas of the teeth adjacent to the interdental spaces including the following: buccomesial, buccal, buccodistal, distal, distolingual, lingual, mesiolingual and mesial.

Two interdental brushes of either soft straight or waist-shaped design were randomly allocated to the four sites. With regard to the size of the interdental spaces, the following brushes were applied: straight soft interdental brushes of either 3 mm diameter (red) or 4 mm diameter (blue), or waist-shaped brushes of either 5-3-5 mm diameter (No. 3, white) or 7-4-7 mm diameter (No. 5, red), respectively. Randomization was performed via a online available tool.For each patient, the two brushes were randomly assigned to either the right or the left side with the concordant dental interspaces. For oral hygiene, additionally to an electric toothbrush and tooth paste, patients were instructed only to use the interdental brushes at the previously determined sites. Following this procedure, non-surgical periodontal therapy using curettes and sonic scaler was performed by skilled periodontists with a specialization in periodontology (SH, HH, CW, Division of Conservative Dentistry and Periodontology, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria). Patients were provided with a sufficient number of interdental brushes for home use until the next appointment. To complete periodontal therapy, time point three (T3) was scheduled within two weeks after T2. Reevaluation was performed eight weeks later at the final appointment (T4).

Intervention type



Not Applicable

Drug names

Interdental brushes

Primary outcome measure

Plaque index measured using site-specific plaque index at baseline and 8-weeks

Secondary outcome measures

1. Probing pocket depth measured using periodontal probe at baseline and 8-weeks
2. Bleeding on probing measured by visual inspection at baseline and 8-weeks
3. Plaque control record (PCR) measured using visual inspection at baseline and 8-weeks
4. Approximal plaque index (API) measured using visual inspection at baseline and 8-weeks
5. Papillary bleeding index (PBI) measured using visual inspection at baseline and 8-weeks

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. ≥ 35 years of age at time of periodontal therapy start
2. No history of periodontal therapy
3. No physical or mental impairment
4. No medication influencing saliva flow
5. No special dietary restrictions

Participant type


Age group




Target number of participants


Total final enrolment


Participant exclusion criteria

1. Presented with oral diseases other than periodontal disease
2. Suffered systemic diseases that could influence the outcome of therapy (e.g. uncontrolled diabetes mellitus)
3. Not using an electric toothbrush from the same brand
4. Did not have four interdental spaces eligible for the used interdental brushes

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Medical University of Vienna
University Clinic of Dentistry Sensengasse 2a

Sponsor information


Medical University of Vienna

Sponsor details

Spitalgasse 23
+43 (0)1 401600

Sponsor type




Funder type


Funder name

Medizinische Universität Wien

Alternative name(s)

Medical University of Vienna, MediUni Wien

Funding Body Type

government organisation

Funding Body Subtype

Local government



Results and Publications

Publication and dissemination plan

Planned publication in a high-impact peer-reviewed journal.

IPD sharing statement:
The current data sharing plans for this study are unknown and will be available at a later date.

Intention to publish date


Participant level data

To be made available at a later date

Basic results (scientific)

Publication list

2020 results in (added 28/05/2020)

Publication citations

Additional files

Editorial Notes

28/05/2020: Publication reference and total final enrolment number added. 22/11/2019: Background an study aims were added to the plain English summary 19/11/2019: Trial’s existence confirmed by Ethics Committee of the Medical University of Vienna