The effectiveness of conically shaped compared with cylindrically shaped interdental brushes - a randomized controlled clinical trial

Aim: The purpose of this study was to compare the effectiveness of conically shaped versus cylindrically shaped interdental brushes (IDB) in patients receiving supportive periodontal therapy. Materials and methods: Periodontal maintenance patients volunteered to be enrolled into this randomized controlled examiner-blind parallel study. At baseline and after 3 months, plaque scores, bleeding upon pocket probing scores and probing pocket depth (PPD) were assessed. The type of IDB (conical or cylindrical) was randomly assigned to each patient and individual instruction was provided regarding the method of use and the appropriate size. Only those approximal sites that had sufficient space for the IDB were eligible, and for those sites the data were analysed separately. Analyses were performed for all eligible approximal surfaces and a sub-analysis was performed for vestibular and lingual surfaces. Results: In total, 51 participants attended the baseline and the 3-month clinical appointments. Overall, there was no difference between conical and cylindrical IDBs. However, the conical IDB showed significantly higher plaque and bleeding scores at the lingual approximal sites. The cause of this difference was an increase in plaque and bleeding scores compared with baseline. With respect to the PPD, no difference between the IDBs was observed. Conclusion: Within the limitations of this experiment, the conical IDBs are less effective than cylindrical IDBs with respect to lingual approximal plaque removal. Thus, in patients receiving supportive periodontal therapy, the cylindrical shape should be the first choice of IDB to obtain and maintain gingival health around natural teeth.