Cleansing Efficacy of Waist-shaped Interdental Brushes. A Randomized-controlled Crossover Study.
Phase: NA
Conditions: Periodontitis, Adult
Sponsor: Medical University Innsbruck

Study protocol, October 10th 2017 
 
Cleansing efficacy of waist-shaped interdental brushes. A randomized-controlled 
crossover study. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Rationale 
The use of interdental brushes is the most effective method to remove biofilm from 
interproximal sites. Oral line angles are predilection sites of plaque accumulation when 
interdental brushes are inserted bucally / labially only. The aim of this study is to compare the 
cleansing efficacy of waist-shaped interdental brushes (Circum®, Topcaredent, Zurich, CH) 
with that of cylindric interdental brushes (IDB, Topcaredent, Zurich, CH) in interproximal 
sites in periodontal maintenance patients. 
The null hypothesis is that there will be no difference in plaque indices between the two 
interdental brushes at interproximal tooth sites of patients with opened interdental spaces. 
 
Ethical approval 
The study was approved by the Ethics Committeee of the Medical Universty of Innsbruck, 
Austria (ID AN5123). 
 
Study design 
Randomized-controlled by toss of a coin 
Single-blind: Two calibrated examiners 
Crossover: Two intervention periods of 30 days each; wash out period one week 
 
 
Study subjects 
Twenty periodontal patients of the University Hospital of Dental Prosthetics and Restorative 
Dentistry, Medical University of Innsbruck 
Inclusion criteria: 
 Completion of active periodontal treatment 
 Maximum probing pocket depths of 5 mm 
 No site ≥ 4 mm with bleeding on probing 
 Bleeding on probing < 10% 
 Open interproximal spaces both, in mandible and maxilla 
 Presence of > 23 natural teeth with no need for prosthetic rehablilitation 

Exclusion criteria: 
 Oral or systemic diseases other than periodontitis 
 Mucosal / periodontal swelling or suppuration 
 Pregnancy 
 Minority 
 Need for frequent drug consumption 
 
Teeth with ceramic restorations and implants are excluded from analysis. 
Recruition period: September 1st to November 30th 2017 
Data collection period: December 1st to March 30th 2018 
 
Clinical parameters 
Primary outcome measure: Plaque index by Quigley and Hein modified by Turesky et al. 
1970 (T-QHI) (Turesky et al., 1970) 
Secondary outcome measure: papillary bleeding index (PBI) by Saxer and Mühlemann (Saxer 
et al., 1977) 
Both are assessed by two blinded and calibrated examiners at four sites per tooth: 
mesiobuccal, distobuccal, mesiolingual, and distolingual including the line angles. 
 
Clinical intervention 
Visit 1: 
1) Pre-intervention: professional tooth cleaning. 
2) Each proband is instructed by one dental hygienist with two sizes of waist-shaped test 
and cylindric control brushes, respectively, to guide the brushes from the buccal / 
labial side through the interdental spaces of all teeth four times each. 
3) Randomization to group 1 or group 2 is performed by the toss of a coin. 
 
 
First intervention period 30 days: Group 1 starts with using waist-shaped and group 2 starts 
with using cylindric brushes. 
 
Visit 2: 
1) Primary and secondary outcome parameters are measured (two calibrated blinded 
examiners 
2) Professional tooth cleaning 
3) Re-instruction by the dental hygienist 

Second intervention period 30 days: Group 2 using waist-shaped and group 1 using 
cylindric brushes. 
 
Visit 3: 
1) Primary and secondary outcome parameters are measured (two calibrated blinded 
examiners 
2) Professional tooth cleaning 
 
 
In addition, probands use the electric toothbrush (Oral-B® CrossAction, Procter & Gamble, 
Taunus, D) with toothpaste (Colgate total original®, Colgate & Palmolive, Vienna, AT) and 
are instructed not to use any chemical oral rinsing solution during the study period. 
 
Statistical analysis 
Sample size calculation is based on a study by Chongcharoen et al. 2012. 
For descriptive analysis, median and interquartile range are given. The mode is defined as the 
T-QHI and PBI grade most often measured in an individual. On the site level, T-QHI is 
converted into a dichotomous index, and the odds ratio and confidence interval (CI) for 
establishing plaque free interdental sites are calculated with logistic regression analysis with a 
significance level of p < 0.05.