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
Mr Christian Wehner
+43 650 7730390
The influence of different interdental brush designs on the efficacy of plaque removal during non-surgical periodontal treatment: A split‐mouth randomized controlled trial
Waist-shaped interdental brushes yield better cleaning efficacy than straight designed brushes in patients undergoing periodontal therapy.
Approved 27/10/2016, Ethics Committee of the Medical University of Vienna (Borschkegasse 8b/6; A-1090 Vienna, Austria; ethikkommission.meduniwien.ac.at; +43 1 40 400 – 21470), ref: Nr. 1670/2016
Split-mouth randomized controlled trial
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
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).
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
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
Medical University of Vienna
+43 (0)1 401600
Medizinische Universität Wien
Medical University of Vienna, MediUni Wien
Funding Body Type
Funding Body Subtype
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)
2020 results in https://pubmed.ncbi.nlm.nih.gov/32458074/ (added 28/05/2020)