Measurement of bristle splaying of toothbrushes using digital imaging and evaluation of plaque removal efficacy over 3 months: A randomized controlled trial (RCT)

Abstract

Objective The aim of this study was to develop an objective method to assess the degree of bristle splaying of used manual toothbrushes and to investigate their plaque removal efficacy. Methods A randomized controlled trial targeting Hiroshima University students was performed to assess the plaque removal efficacy of polybutylene terephthalate (PBT) manual toothbrushes. Participants were randomly assigned to the soft toothbrush group (n = 40) or the medium toothbrush group (n = 40). A small number of participants discontinued the intervention for personal reasons in both the medium (n = 6) and soft (n = 2) toothbrush groups. Toothbrushes were collected immediately after first use (T0: baseline), after 1 month of use (T1: month 1), after 2 months of use (T2: month 3) and after 3 months of use (T3: month 6), following the allocation of a new toothbrush. The bristle surface area was measured using digital software. Results The surface area of the bristles was significantly greater at T1, T2 and T3 than at T0 in the medium toothbrush group (n = 34) and soft toothbrush group (n = 38) (P < .001). Importantly, plaque removal efficacy, calculated from a modified plaque control record score and modified patient hygiene performance score, was significantly lower at T2 than at T0 in both groups. Conclusions Our method for evaluation of bristle splaying is considered to be reliable and reproducible. PBT toothbrushes may become less effective after two months of use.

Changes in the Bristle Stiffness of Polybutylene Terephthalate Manual Toothbrushes over 3 Months: A Randomized Controlled Trial

“…We performed a single-center randomized controlled trial (RCT) to evaluate the bristle stiffness and bristle splaying of soft and medium manual toothbrushes among dental and medical students of Hiroshima University [4]. The study was performed at the Department of Public Oral Health, Graduate School of Biomedical and Health Sciences, Hiroshima University.…”

“…Therefore, we aimed to analyze 40 participants per group. Eligibility criteria and participant characteristics have also been described in our previous paper [4]. Eligible participants were Hiroshima University students who were ≥18 years of age and <40 years of age, with at least 18 natural teeth excluding the third molars.…”

“…Participants were then randomly assigned to the soft toothbrush group (n = 40) or the medium toothbrush group (n = 40) with a 1:1 allocation. The method of random allocation was described in our previous paper [4]. Before the start of this study, a dental hygienist provided the participants with instructions for toothbrushing.…”

“…Before the start of this study, a dental hygienist provided the participants with instructions for toothbrushing. Participants were instructed to brush their teeth using a gentle scrubbing technique [4]. Participants were also instructed to brush their teeth for 3 minutes twice per day with an allocated toothbrush.…”

“…However, toothbrushes begin to wear out and become less effective in cleaning teeth over time [2,3]. We previously reported that polybutylene terephthalate (PBT) toothbrushes become less effective in removing dental plaque after two months of use [4]. Therefore, regular toothbrush replacement is recommended to maintain good oral hygiene.…”