A Clinical Evaluation of the Plaque Removal Efficacy

A Clinical Evaluation of the Plaque Removal Efficacy
of Five Manual Toothbrushes
N.C. Sharma, DDS J. Qaqish, BSc
BioSci Research
Las Vegas, NV, USA
P.A. Walters, RDH, MSDH, MSOB J. Grender, PhD A.R. Biesbrock, DMD, PhD, MS
Procter & Gamble Company
Health Care Research Center
Mason, OH, USA
Abstract
• Objective: To assess and compare the plaque removal efficacy of five different Oral-B® manual toothbrushes: CrossAction®
Pro-Health® (CAPH), CrossAction® (CA), Exceed® (EX), Advantage 123® (ADV 123), and Indicator® (IND).
• Methods: This was a single-use, five-treatment, examiner-blind, randomized, five-period (visit) crossover study, with 10 different
treatment sequences (groups) that determined the order in which the five toothbrushes were assigned at study visits. Three toothbrushes had an advanced CrissCross® bristle design (CAPH, CA, EX), while two had more standard designs with straight bristles
(ADV 123 and IND). At the first visit, subjects disclosed their plaque with disclosing solution, and an examiner performed a baseline
plaque examination using the Rustogi, et al. Modification of the Navy Plaque Index (RMNPI). Subjects brushed for one minute
with their assigned toothbrush under supervision, after which they again disclosed their plaque and were given a second plaque
examination. The same procedure was followed for each of the visits in turn.
• Results: All five manual toothbrushes showed a statistically significant (p < 0.0001) reduction in plaque from baseline for the whole
mouth (84% to 93%), gingival margin (74% to 88%), and approximal surfaces (95% to 99%). For pair-wise treatment comparisons
for all three plaque measures, CAPH, CA, and EX demonstrated statistically significantly better plaque removal than ADV 123 and
IND (all p < 0.018). No other treatment comparisons were statistically significant.
• Conclusion: All five manual toothbrushes showed highly effective plaque reduction for whole mouth, gingival margin, and approximal
surfaces. Comparisons between brushes showed consistent advantages for CAPH, CA, and EX compared to ADV 123 and IND
for all three plaque measures, indicating that advances in toothbrush design can further enhance plaque removal.
(J Clin Dent 2010;21:8–12)
(IND), which has standard, flat-trim bristles, and Advantage
123® (ADV 123), which has multi-level straight bristles. More
advanced models with CrissCross® bristles, specifically aimed at
helping to remove plaque from hard-to-reach areas, in particular from between the teeth and along the gum line, include CrossAction® Pro-Health® (CAPH), CrossAction® (CA), and Exceed®
(EX). Although manufacturers may introduce brush head design features with the sole purpose of achieving better plaque
removal, such claims should be substantiated by appropriate
plaque removal data. Thus the purpose of the present investigation was to assess the plaque removal efficacy of these different
toothbrush models under controlled experimental conditions,
and determine whether the brushes could be differentiated in
terms of their effectiveness.
Introduction
Efficient plaque removal is essential for the prevention of
dental caries and gingivitis, and forms the basis of any good daily
oral hygiene routine. But achieving and maintaining optimal
oral health, and hence avoiding periodontal disease, requires
highly effective plaque removal methods.1,2 The manual toothbrush is widely used by the public, and is often the sole means
of plaque removal for many people. However, there is evidence
for sub-optimal brushing technique and for brushing time to be
less than ideal.3-5 Manual toothbrush users therefore need to
ensure that their chosen brush and their personal technique will
remove plaque successfully and efficiently, and do so from all
tooth surfaces.
Manufacturers of manual toothbrushes aim for innovations in
brush head design that will help to compensate for sub-optimal
brushing technique and brushing time (e.g., Beals, et al 6). The
performance of any new brush, however, should be established
within controlled clinical studies. Single-use comparative clinical studies with a crossover design can be used to assess differences in plaque removal efficacy between toothbrushes.7-9
Among the popular manual toothbrushes in use today are a
number of different models manufactured by Oral-B® (Procter &
Gamble, Cincinnati, OH, USA), with end-rounded bristles for
safety purposes. The more basic designs include Indicator®
Materials and Methods
Subjects and Study Design
Before the start of the study, the protocol was approved by the
BioSci Research Canada, Ltd. Institutional Review Board, and
only subjects who gave informed consent were allowed to take
part in any study procedures. To be included in the study, subjects who were recruited from the general population were required to be in good general health, between 18 and 70 years of
age, and to have at least 16 natural teeth with facial and lingual
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Vol. XXI, No. 1
The Journal of Clinical Dentistry
9
scoreable surfaces (at least four molars). Subjects with evidence
of neglected dental health were excluded from the study, and
subjects were not permitted to continue if during the study they
participated in any other clinical investigation of oral or dental
products.
The study had a single-use, five-treatment, examiner-blind,
randomized, five-period (visit), crossover design with 10 different
treatment sequences (groups), AEBDC, EDACB, DCEBA, etc.,
that were balanced for first order carryover effects. The groups determined the inclusion and exclusion criteria entered the study.
Subjects then disclosed their plaque by swishing with red disclosing solution (Chroma-O-Red® erythrosin FD&C red 3 solution, Germiphene Corp., Brantford, Ontario, Canada), and an order was determined in which the five toothbrushes were assigned
at study visits, where A, B, C, D, and E represented CAPH, CA,
EX, ADV 123, and IND, respectively (Figure 1). Subjects were
randomized in equal numbers to one of the 10 groups.
Figure 2. Rustogi, et al. Modification of the Navy Plaque Index.10 Disclosed
plaque was scored in each tooth area as present (scored as 1) or absent (scored
as 0) and recorded for both buccal and lingual surfaces. Whole mouth = areas
A, B, C, D, E, F, G, H, and I; gingival margin (gum line) = areas A, B, and C;
approximal = areas D and F.
CrissCross!
bristles; multisection power
tip bristles; outer
gingival
stimulators
CrissCross!
bristles; multisection power
tip bristles
CrissCross!
bristles; multisection power
tip bristles
A
B
C
Multi-level
straight bristles;
multi-section
power tip
bristles; outer
gingival
stimulators
D
Standard, flattrim bristles
Ee
Figure 1. Study toothbrushes: A = CrossAction Pro-Health (CAPH); B = CrossAction (CA); C = Exceed (EX); D = Advantage 123 (ADV 123); E = Indicator
(IND).
Subjects were instructed to use their own toothpaste and toothbrush at home between study visits, and to do so throughout the
study. Subjects were also instructed to refrain from all oral
hygiene procedures (for approximately 23 to 25 hours), and
from eating, drinking, chewing gum, or smoking (previous four
hours) prior to their appointment time.
At the first study visit, subjects who had given signed informed consent, and who were eligible in terms of the inclusion
and exclusion criteria, entered the study. Subjects disclosed
their plaque by swishing with red disclosing solution (ChromaO-Red erythrosin FD&C red 3 solution; Germiphene Corp.,
Bradford, Ontario, Canada) for one minute. An examiner then
performed a baseline plaque examination using the Rustogi, et
al. Modification of the Navy Plaque Index (RMNPI).10 Plaque
was evaluated on each of nine sites on buccal and lingual tooth
surfaces (i.e., total of 504 sites for 28 teeth). Plaque was scored
as either absent (score = 0) or present (score = 1) on each site,
and from these scores average whole mouth, marginal, and interproximal (approximal) plaque scores were computed for each
subject. The surface areas are defined in Figure 2.
Subjects were instructed to brush for one minute with their
assigned toothbrush and a marketed toothpaste under supervision, unaided by access to a mirror. After brushing their teeth, the
subjects again swished with red disclosing solution for one
minute to reveal the plaque, and this was followed by a second
plaque examination. The same procedure was followed for each
of the visits in turn, which were separated by an interval of at
least 23 hours, and at each visit subjects were assigned brushes
according to their treatment sequence. The same marketed toothpaste with sodium fluoride was used for brushing at each study
visit (Crest® Cavity Protection, Procter & Gamble, Cincinnati,
OH, USA). Subjects were assessed at each visit for their eligibility to continue in the study.
Data Analysis
A sample size of 50 subjects was estimated for this crossover
study to ensure an 80% (power = 1–β) or greater chance of
detecting a difference between a pair of treatment groups of at
least 0.024 whole mouth RMNPI units (assuming an estimate of
SD = 0.06), and at least 0.04 gingival margin or approximal
RMNPI units (assuming an estimate of SD = 0.10).
For the primary analysis, average whole mouth RMNPI scores
obtained for each subject were scored at baseline and following
brushing, and the differences (baseline minus post-brushing)
were calculated for each of the five periods. Analysis of covariance (ANCOVA) for a crossover design was applied to the differences, with baseline scores as covariates, to assess treatment
effects. Pair-wise testing between individual groups was conducted using t-tests between adjusted treatment mean scores
(baseline minus post-brushing difference) from the ANCOVA.
Additional analyses were carried out on gingival margin and approximal RMNPI scores using the same methods. The ANCOVA
model included terms for baseline plaque, period, treatment,
carryover, and subjects. No statistically significant carryover
effects (p  0.236) were found for either whole mouth, gingival
margin, or approximal scores, and this term was dropped from
the final analysis for assessing treatment group differences. All
comparisons were two-sided with a significance level of α = 0.05.
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The Journal of Clinical Dentistry
Results
A total of 50 subjects were enrolled in the study and all subjects were included in the statistical analysis. Table I shows the
demographic data for the subjects.
Table I
Baseline Demographic Characteristics (N = 50)
Gender
Female
Male
Age (years)
Mean (SD)
Min-Max
31
19
31.46 (12.48)
18–67
SD = standard deviation
Whole Mouth
Mean whole mouth RMNPI scores for pre-brushing and for
post-brushing plaque reduction are shown for all five treatments
in Table II, along with p-values for reductions from baseline and
for treatment comparisons. Baseline whole mouth average
RMNPI scores ranged from 0.639 to 0.645, with no statistical
differences among the five treatments (p = 0.775). All five treatments showed statistically significant whole mouth plaque
removal from baseline (all p < 0.0001), with reductions ranging
from 0.544 (IND) to 0.599 (CAPH). Treatment comparisons
showed significantly better plaque removal for CAPH, CA, and
EX versus ADV 123 and IND (all p £ 0.0003). No other treatment comparisons were statistically significant.
Table II
Whole Mouth Plaque Reduction Using the
Rustogi, et al. Modified Navy Plaque Index (RMNPI)
Treatment
CAPH
CA
EX
ADV 123
IND
Pre-Brushing
(Baseline)
Mean (SD)
Post-Brushing
Reduction
Adjusted Mean
(SE)
% Difference from
Baseline in
Plaque Removal
(p-value)
0.644 (0.037)
0.645 (0.052)
0.643 (0.040)
0.639 (0.041)
0.645 (0.044)
0.599 (0.007)
0.585 (0.007)
0.582 (0.007)
0.549 (0.007)
0.544 (0.007)
93.0 (p < 0.0001)
90.7 (p < 0.0001)
90.5 (p < 0.0001)
85.9 (p < 0.0001)
84.3 (p < 0.0001)
Treatment Comparisona
% Difference Between Brushes
in Plaque Removal (p-value)
CAPH versus ADV 123
CAPH versus IND
CA versus ADV 123
CA versus IND
EX versus ADV 123
EX versus IND
9.1 (< 0.0001)
10.1 (< 0.001)
6.6 (< 0.0001)
7.5 (< 0.0001)
6.0 (0.0003)
6.8 (< 0.0001)
SD = standard deviation
SE = standard error
a
No other pair-wise comparisons were statistically significant (p > 0.05).
Gingival Margin
Table III shows mean gingival margin RMNPI scores for all
five treatments and comparisons between treatments. The baseline average score was 1.0 for all treatments. Relative to baseline,
all five treatments showed statistically significant plaque removal
at the gingival margin (all p < 0.0001). CAPH, CA, and EX
showed significantly better plaque removal at the gingival margin
Vol. XXI, No. 1
Table III
Gingival Margin Plaque Reduction Using the
Rustogi, et al. Modified Navy Plaque Index (RMNPI)
Treatment
CAPH
CA
EX
ADV 123
IND
Pre-Brushing
(Baseline)
Mean (SD)
Post-Brushing
Reduction
Adjusted Mean
(SE)
% Difference from
Baseline in
Plaque Removal
(p-value)
1.000 (0.001)
1.000 (0)
1.000 (0.001)
1.000 (0)
1.000 (0)
0.877 (0.019)
0.839 (0.019)
0.838 (0.019)
0.761 (0.019)
0.741 (0.019)
87.7 (p < 0.0001)
83.9 (p < 0.0001)
83.8 (p < 0.0001)
76.1 (p < 0.0001)
74.1 (p < 0.0001)
Treatment Comparisona
% Difference Between Brushes
in Plaque Removal (p-value)
CAPH versus ADV 123
CAPH versus IND
CA versus ADV 123
CA versus IND
EX versus ADV 123
EX versus IND
15.2 (< 0.0001)
18.4 (< 0.0001)
10.2 (0.0002)
13.2 (< 0.0001)
10.1 (0.0002)
13.1 (< 0.0001)
SD = standard deviation
SE = standard error
a
No other pair-wise comparisons were statistically significant (p > 0.05).
versus ADV 123 and IND (all p £ 0.0002). No other treatment
comparisons were statistically significant.
Approximal
Mean approximal RMNPI scores and treatment comparisons
are shown in Table IV. Baseline scores were 0.999 or 1.0 for all
treatments. All five treatments had statistically significantly
lower post-brushing interproximal plaque scores versus baseline
(all p < 0.0001). Significant treatment comparisons were seen for
CAPH, CA, and EX versus ADV 123 and IND (all p £ 0.0175).
No other treatment comparisons were statistically significant.
No treatment-related adverse effects were reported for any of
the brushes during the study.
Table IV
Approximal Plaque Reduction Using the
Rustogi, et al. Modified Navy Plaque Index (RMNPI)
Treatment
CAPH
CA
EX
ADV 123
IND
Pre-Brushing
(Baseline)
Mean (SD)
Post-Brushing
Reduction
Adjusted Mean
(SE)
% Difference from
Baseline in
Plaque Removal
(p-value)
0.999 (0.008)
1.000 (0.003)
1.000 (0.001)
0.999 (0.006)
1.000 (0)
0.991 (0.008)
0.982 (0.008)
0.977 (0.008)
0.953 (0.008)
0.949 (0.008)
99.2 (p < 0.0001)
98.2 (p < 0.0001)
97.7 (p < 0.0001)
95.4 (p < 0.0001)
95.4 (p < 0.0001)
Treatment Comparisona
CAPH versus ADV 123
CAPH versus IND
CA versus ADV 123
CA versus IND
EX versus ADV 123
EX versus IND
% Difference Between Brushes
in Plaque Removal (p-value)
4.0 (0.0002)
4.4 (< 0.0001)
2.9 (0.0046)
3.5 (0.0011)
2.4 (0.0175)
3.0 (0.0049)
SD = standard deviation
SE = standard error
a
No other pair-wise comparisons were statistically significant (p > 0.05).
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The Journal of Clinical Dentistry
Discussion
An impressive variety of toothbrushes is available to the consumer, and the public can be confident that manufacturers strive
to introduce new models that offer advantages over those that are
currently available. Advances in the design of the brush handle
and head, and the configuration and type of brush head bristles,
often seek to maximize comfort and acceptability, which should
directly help users comply with the well-known recommendations for optimal brushing time and frequency (two minutes,
twice daily). Crucially though, new design features are intended
to help the user achieve highly effective plaque removal despite
an often inefficient personal brushing technique.
Dental professionals and the public can make more informed
choices between different commercial products and their potential benefits when the relative merits of models for improved oral
hygiene have been evaluated. Single-use comparative clinical
studies7-9 are useful for determining the relative plaque removal
effectiveness of novel brushes, which may provide an indication
of gingival health benefits long term.11 Ideally, these single-use
studies should be run as crossover designs, where the design is
balanced for first-order carryover effects. In addition, the design
should allow the treatment effect to be estimated in the presence
of carryover effects, if they indeed exist. The design in the
current study has these features in that it is balanced for carryover and can provide an estimate of treatment effects with minimal increase in variance, even if carryover is included in the
model. Other designs, such as the two-treatment, two-period,
two-sequence crossover design, do not contain these desirable
properties.12
The present single-use comparative study of plaque removal
effectiveness scored plaque on all tooth surfaces using a wellaccepted index,10 and showed highly significant (p < 0.0001)
plaque reductions from baseline with all five models of manual
toothbrushes. Significant plaque reduction (Figure 3) was seen
not only for the entire mouth (at least 84%), but also at those
surfaces known to be difficult-to-reach during normal use, i.e.,
along the gum line (at least 74%) and between the teeth (at least
95%). Of specific interest, and of direct importance for differentiating between brushes in terms of their plaque removal
effectiveness, was the finding that CA, CAPH, and EX were
11
consistently and significantly (p < 0.05) better than ADV 123 or
IND at removing plaque according to all three of the plaque
measures (whole mouth, approximal, and gingival margin).
A number of design features may differentiate commercially
available brushes, but the defining feature of the three brushes
that showed superiority in our study, i.e., CA, CAPH, and EX,
is the bristle configuration, specifically, CrissCross bristles angled in opposing directions. These results can be seen to support
the already documented benefits of CrossAction brushes.13 The
CrissCross configuration aids plaque removal from hard-toreach areas, and in this respect has advantages over the straight
bristle configuration seen in numerous toothbrush models, and
currently in the IND and ADV 123 brushes used in this study. As
noted by Cugini and Warren,13 the CrissCross bristle design
more effectively removes plaque on both forward and backward
strokes, allowing greater coverage of the tooth surface than
straight bristles.
In two separate four-period crossover studies that compared
plaque removal effectiveness between EX and Asian Colgate®
360° (Colgate-Palmolive Company, New York, NY, USA), the
EX model with a CrissCross bristle configuration showed significantly greater plaque removal.14,15 These findings, together
with the results of CA comparisons that include some earlier
models,9,16 provide highly relevant data for assessing the relative
merits of different brushes.
Conclusions
Five different manual toothbrushes all showed statistically
significant plaque reduction from baseline with single use for
whole mouth (at least 84%), gingival margin (at least 74%), and
approximal surfaces (at least 95%). All brushes were highly
effective, but comparisons between brushes showed consistent
and statistically significant (p < 0.05) advantages for CAPH, CA,
and EX in comparison with ADV 123 and IND for all three
plaque measures. These differences demonstrate that advances
in toothbrush design can produce even greater plaque removal
results.
Acknowledgments: The authors thank Dr. Jane Mitchell (MWS Ltd, Staffordshire, UK) for assistance with manuscript preparation. This study was supported
by the Procter & Gamble Company.
For further correspondence with the authors of this paper,
contact Dr. Aaron Biesbrock—biesbrock.ar@pg.com
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Figure 3. Percent plaque removal for whole mouth, gingival margins, and
approximal surfaces with all five brushes: CAPH, CA, EX, ADV 123, and IND.
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