A 5‐week randomized clinical evaluation of a novel electric toothbrush head with regular and tapered bristles versus a manual toothbrush for reduction of gingivitis and plaque

Abstract Objective To evaluate the efficacy of an oscillating‐rotating (O‐R) electric rechargeable toothbrush with a novel round brush head comprised of regular and tapered bristles in reducing plaque and gingivitis versus a manual toothbrush. Methods This was a randomized, examiner‐blind, parallel group, five‐week study. Participants with mild‐to‐moderate plaque and gingivitis received an oral examination and were evaluated for baseline plaque (Rustogi Modified Navy Index), gingivitis (Modified Gingival Index) and gingival bleeding (Gingival Bleeding Index). Qualifying participants were randomly assigned to the novel Oral‐B sensitive brush head (EB60) on an Oral‐B Vitality O‐R handle (D12) or an ADA manual toothbrush. Participants brushed twice daily with the assigned brush and a standard fluoride dentifrice for 5 weeks before returning for an oral examination and plaque and gingivitis evaluations. Results A total of 150 participants were randomized to treatment and completed the study (mean age = 45.7 years). Both brushes demonstrated a statistically significant reduction in number of bleeding sites versus baseline (P < 0.001). At Week 5, the number of bleeding sites was reduced from baseline by 11.15 (52.2%) for the O‐R brush and 5.04 (23.6%) for the manual brush. The treatment difference was statistically significant (P < 0.001). Significant reductions versus baseline (P < 0.001) were also seen for both brushes for MGI, GBI and Rustogi plaque measures (whole mouth, gingival margin and proximal), but the O‐R brush produced significantly greater reductions versus the manual brush (P < 0.001). Conclusion The O‐R handle and round brush head with tapered and regular bristles produced greater plaque and gingivitis reductions than the manual brush.


| INTRODUC TI ON
Periodontal disease is multifactorial, but typically involves an inflammatory response to dental plaque. 1,2 It is prevalent, with approximately 80% of the population experiencing gingivitis, the earliest stage of periodontal disease. 3 Gingivitis develops within days of dental plaque accumulation, and if not reversed may progress to periodontitis with clinical attachment loss. 4 Preventing gingivitis is a key factor in oral health, therefore effective oral hygiene with thorough plaque removal and control is essential. 5 Among mechanical methods for plaque removal, the toothbrush is the most frequently used device.
A multitude of manual and electric (ie, power) brush designs are now available, including brushes with advanced technologies designed to improve mechanical plaque removal and the brushing experience. The oscillating-rotating (O-R) brush technology has been thoroughly researched and systematic reviews show it is more effective for removing dental plaque and reducing gingivitis than a manual brush. 6 There is also evidence that O-R brushes reduce plaque and gingivitis more than sonic brushes in the short term. 7 Many advanced toothbrush models include innovations in bristle design, such as end rounded, angled, multi-level and CrissCross ® bristle arrangements along the brush head. Tapered bristles (also known as super thin or ultrathin bristles) have also been incorporated into manual brush designs to better reach proximal and other hard-to-reach areas, 8 while providing a gentle brushing experience. 9,10 Tapered bristles are more flexible and much thinner than others, and have an extended taper. The plaque removal efficacy of tapered bristles in a manual brush design has been shown in in vitro and in vivo studies. 9,[11][12][13][14][15][16][17][18][19] Recently, a round brush head for O-R electric rechargeable brushes has been developed and designed according to consumer preferences for a gentle brushing experience with a mix of regular end-rounded and tapered bristles. The purpose of the current study was to evaluate the efficacy of an O-R brush handle with the novel round brush head comprised of tapered and regular bristles in the reduction of dental plaque and gingivitis versus a manual toothbrush among generally healthy participants with mild-to-moderate plaque and gingivitis over a 5-week period. This is the first reported research on the new brush head.

| Study design
This was a five-week, single-centre, randomized, two-treatment, examiner-blind, parallel group study. Prior to starting the study, Institutional Review Board approval was obtained for the study protocol and informed consent form (16048-11:57:4531-05-2016).
One hundred and fifty-two potential participants were recruited by All Sum Research Center Ltd. in Mississauga, Ontario by phone or email in April of 2016. Participants signed a written informed consent prior to their participation in the study. Qualified participants were instructed to abstain from brushing and performing any oral hygiene 3-6 hours prior to their Baseline and Week 5 visits, and to abstain from eating, chewing gum or drinking after oral hygiene on the morning of their appointments (small sips of water were allowed up until 45 minutes prior to their appointment). At the baseline visit, participants first received an oral examination. This was followed by an assessment of gingivitis using the Modified Gingival Index (MGI) and Gingival Bleeding Index (GBI). 20,21 Next, an assessment of plaque was performed using the Rustogi Modified Navy Plaque Index (RMNPI) after plaque on all surfaces was first stained using Chrom-O-Red erythrosine disclosing solution (Germiphene Corp., Bradford, ON, Canada). 22

| Study population
Participants had to be typical manual toothbrush users 18 years of age or older, in good general health, without orthodontic appliances, and have a minimum of 16 natural teeth with facial and lingual scorable surfaces for consideration. Teeth with scorable surfaces excluded third molars, teeth (or implants) with crowns or bridges, and F I G U R E 1 Test products. Left: Oral-B Vitality brush handle and round brush head with regular end-rounded bristles (centre ring) and tapered bristles (outer ring). Right: Manual toothbrush teeth with large restorations covering >50% of the tooth surface.
Participants qualified for entrance into the study if they met these requirements and had a baseline gingivitis (MGI) score of at least 1.75 but not greater than 2.3, a minimum of 10 bleeding sites (GBI score of 1 or 2), and a whole mouth RMNPI score greater than 0.50. Participants received their assigned products by clinical site personnel in a separate area to ensure the examiner was blinded to treatment assignment. In the same area, they then received verbal and written instructions on oral hygiene and product usage, and were asked to perform a supervised brushing in front of a mirror using the assigned products. Participants using the electric brush were instructed to brush for 2 minutes, twice daily for approximately five weeks with their assigned toothbrush and dentifrice according to manufacturer's usage instructions. Participants using the ADA manual brush were instructed to brush in their usual manner with the assigned products. At the Week 5 visit, all participants were ascertained to still meet the study criteria, including having refrained from brushing for 3-6 hours prior to their appointment, and from eating, chewing gum and drinking as described above. Each participant then received an oral examination, MGI, GBI and RMNPI plaque assessments as described for the Baseline visit.

| Clinical assessments
All clinical assessments were performed by the same experienced examiner 23,24 at the baseline and Week 5 visits. The safety assessment included visual examination of the intra-oral and oropharyngeal soft tissues, lips and the peri-oral area using a standard dental light, dental mirror and gauze. The dentition was examined using a standard dental light, dental mirror and air syringe.

| Data analysis and statistical methods
The sample size was determined by power analyses with α = 0.05, using a 2-sided test. Based on whole mouth MGI variability of 0.084 and whole mouth RMNPI variability of 0.042, it was determined that a sample size of 75 participants in each group would provide 90% power to detect a difference in mean MGI and RMNPI scores of 0.050 and 0.025 units, respectively, between treatments. Statistical analyses were performed to determine group differences. A twosample t test was used to compare group differences for age; gender was compared using a chi-square test, and for ethnicity and smoking status using Fisher's exact test. Separate calculations were per-

| RE SULTS
A total of 150 participants were randomized to treatment; all participants completed the study (Figure 2). The mean age of participants was 45.7, with ages ranging from 18 to 77 years. Overall, 64% of participants were female, and 92% were nonsmokers. Statistical analyses showed that the treatment groups were well-balanced for age, gender and smoking status (P ≥ 0.496, Table 1).

| MGI, GBI and number of bleeding sites
The baseline means and Week 5 reductions in MGI, GBI and number of bleeding sites are shown in Table 2. There were no statistically

| Plaque scores
Randomized participants presented at baseline with moderate plaque accumulations (whole mouth RMNPI >0.50). Baseline whole mouth RMNPI scores were 0.633 for the O-R group and 0.625 for the manual group, with no statistically significant difference between the groups for any baseline plaque measure (whole mouth, proximal, gingival margin; P ≥ 0.246). At Week 5, statistically significant reductions in whole mouth, gingival margin and proximal region RMNPI scores were observed for both groups (P < 0.001 for each measure) (

| Safety
No adverse events were observed or reported during the study.

| D ISCUSS I ON
Manual and electric brush designs have improved as a result of research on brush handles, brush heads and bristle configurations.
Tapered bristles represent one such improvement whereby thinner, more flexible bristles can remove dental plaque, including in hardto-reach areas, 8 while providing a gentle brushing experience. 9,10 Tapered bristles may also deliver functional chemistry in dentifrice to hard-to-reach areas better than conventional bristles. Since an electric toothbrush head control with only endrounded bristles was not included in this trial, it is not possible to ascertain the relative efficacy contribution of the electric brush technology relative to the tapered bristles. It is possible to make broad comparisons based on a large systematic review evaluating the plaque-and gingivitis-reducing effects of electric toothbrushes collectively versus manual toothbrushes. 6 The review included fifty-five clinical trials, twenty-seven of which evaluated oscillating-rotating electric toothbrushes using various handles, brush heads and clinical indices. Looking across the 1-to 3-month studies, electric toothbrushes were found to have an 11% advantage versus manual for plaque removal a 6% benefit for gingivitis reduction.
In this 5-week trial, the O-R toothbrush with the novel head comprised of tapered and end-rounded bristles showed a 10% plaque removal advantage and an 8.5% gingivitis reduction advantage versus the manual toothbrush.   28,29 This study focused on the therapeutic effects of the new brush head on an entry-level handle among usual manual toothbrush users.
Future research could involve evaluations of the brush head on more advanced handles, comparisons versus different toothbrush controls, assessments among typical electric toothbrush users and/or a survey of patient experience.

| CON CLUS IONS
The current study demonstrates the efficacy of a novel round sensitive brush head with tapered bristles on an O-R electric toothbrush handle. In comparison to a standard manual brush with end-rounded filaments, the O-R brush resulted in significantly greater reductions in gingival inflammation, number of bleeding sites and plaque. This brush head and handle combine the proven efficacy of the O-R technology with tapered bristles to provide effective cleaning, particularly in hard-to-reach proximal areas.

| Scientific rationale for study
Tapered bristles, used in manual toothbrushes to reduce plaque and gingivitis, have been incorporated with regular bristles in a round brush head to provide efficient plaque removal. This study evaluated the efficacy of the new head in reducing plaque and gingivitis on an entry-level O-R handle versus a manual brush.

| Principal findings
The brush head and O-R handle provided greater plaque and gingivitis reductions than the manual brush.

| Practical implications
The new brush head with tapered and end-rounded bristles is an effective option for patients with poor plaque control or gingivitis.