J Clin Periodontol. 2019;00:1–10.
1 | INTRODUCTION
Periodontitis and caries are the most commonly occurring den-
tal diseases worldwide (Marcenes et al., 2013) and account for
about 60% of tooth loss (Glockmann, Panzner, Huhn, Sigusch, &
Glockmann, 2011). The main aetiology for both diseases is accu-
mulation of bacterial plaque on tooth surfaces (Löe, Theilade, &
Jensen, 1965; Marsh & Nyvad, 2008; Newman, 1986; Theilade,
Wright, Jensen, & Löe, 1966). It has been well established that the
cornerstone for prevention of periodontitis and caries is through
supragingival plaque control and fluoride usage, respectively.
Althou gh personal ora l hygiene methods su ch as toothbrushi ng can
prevent biofilm accumulation and gingivitis (Tonetti et al., 2015), it
has to be noted that proper brushing skills are vital to achieve this.
Effective brushing is linked to a number of influencing factors.
Usually, brushing skills are acquired through parents, and it takes
time to actually master them perfectly (Unkel, Fenton, Hobbs, &
DOI: 10.1111/jc pe.13126
Long‐term impact of powered toothbrush on oral health:
11‐year cohort study
Vinay Pitchika1 | Christiane Pink1 | Henry Völzke2 | Alexander Welk1 |
Thomas Kocher1 | Birte Holtfreter1
This is an open access article under the terms of the Creat ive Commo ns Attri bution-NonCo mmercial License, which permits use, distribution and reproduction
in any medium, provided the original work is properly cited and is not used for commercial purposes.
© 2019 The Authors. Journal of Clinical Periodontology Published by John Wiley & Sons Ltd.
1Department of Restorative Dentistry,
and Preventive and Pediatric
Dentistry, University Medicine Greifswald,
2Institute of Community
Medicine, University Medicine Greifswald,
Vinay Pitchika, Unit of Periodontology,
Department of Restorative Dentistry,
Periodontology, and Endodontology
and Preventive and Pediatric Dentistry,
University Medicine Greifswald,
Fleischmannstr. 42, Greifswald 17475,
The SHIP cohort study is part of the
Community Medicine Research Net (http://
www.mediz in.uni-greif swald.de/cm) of the
University of Greifswald, Germany, which is
funded by the German Federal Ministry of
Education and Research (BMBF, grant no.
01ZZ96030, 01ZZ0701); the Ministry for
Cultural Affairs and the Ministry for Social
Affairs of the Federal State of Mecklenburg-
West Pomerania (SHIP; http://www.mediz
in.uni-greif swald.de/cm). Vi.P was supported
by funding provided by Procter and Gamble
Co. towards personnel costs.
Aims: This study aimed to assess 11-year longitudinal effects of powered toothbrush
on periodontal health, caries and tooth loss in an adult population.
Materials and Methods: Participants of Study of Health in Pomerania (SHIP) cohort
with dental examinations and interview data at SHIP-1, SHIP-2 or SHIP-3 examina-
tions were included. Mixed-effects linear regression models were constructed be-
tween the exposure (manual versus powered toothbrush) and outcome variables
(periodontal status using mean probing depth (PD) and mean clinical attachment loss
(CAL), caries status using DMFS and DFS scores, and tooth loss), adjusting for poten-
tial baseline covariates.
Results: Final baseline (SHIP-1) study sample comprised of 2,819 participants.
Powered toothbrush users increased from 18.3% (SHIP-1) to 36.9% (SHIP-3); were
younger; had significantly less mean PD [β:−0.09(95%CI:−0.16;−0.02)]andmean
CAL [β: −0.19(95%CI:−0.32; −0.07)]progressions;and had 17.7% less DMFS pro-
gression and 19.5% more teeth retained than the manual toothbrushers.
Conclusions: In the long-term, powered toothbrush seems to be effective in reduc-
ing mean PD and mean CAL progressions, besides increasing the number of teeth
caries, gingivitis, oral hygiene, periodontitis, tooth loss, toothbrush
PITCHIKA eT Al .
Frere, 1995). If an improper technique is detected at a later point
of life, it is difficult to modify it (Alcouffe, 1988). Furthermore,
the fine motor skills might degrade with ageing and could impair
maintaining proper oral hygiene in elderly people (Felder, Reveal,
Lemon, & Brown, 1994; Hitz Lindenmüller & Lambrecht, 2011).
Powered toothbrushes (PTB) are advertised as having better
biofilm removal capacity than manual toothbrushes (Verma & Bhat,
2004), which was attested by in vitro studies (Hunt, 2002; Schmidt,
Zaugg, Weiger, & Walter, 2013). Under clinical settings, they were ef-
fective in removing plaque (Rosema, Slot, van Palenstein Helderman,
Wiggelinkhuizen, & Van der Weijden, 2016) and tackling gingivitis
(Yaacob et al., 2014). However, studies assessing the long-term ef-
fectiveness of PTBs on slowing initiation or progression of periodon-
titis are limited (Dentino et al., 2002; Dörfer, Staehle, & Wolff, 2016;
Moritis, Jenkins, Hefti, Schmitt, & McGrady, 2008; Schmalz et al., 2017;
Wilson, Levine, Dequincey, & Killoy, 1993); these studies mainly fo-
cussed on plaque, calculus or gingivitis. In addition to having employed
small sample sizes (maximum of 180 subjects) and short follow-up
times ranging from few weeks to a maximum of 3 years, these studies
did not include tooth loss as an outcome, which is of paramount im-
portance for patients. A recently published Cochrane review concluded
“Powered toothbrushes reduce plaque and gingivitis more than manual
toothbrushing in the short and long term. The clinical importance of
these findings remains unclear” (Yaacob et al., 2014). Similarly, stud-
ies associating PTB usage with caries are limited (Papas et al., 2007;
Willershausen & Watermann, 2001). Furthermore, prospective pop-
ulation-based cohort studies assessing the effectiveness of PTBs are
unavailable as of now.
Therefore, in this study, we aimed to estimate the longitudinal
effects of PTB usage on (a) periodontal health in terms of mean
probing depths (PD) and mean clinical attachment loss (CAL), (b)
coronal caries experience using decayed, missing and filled surfaces
(DMFS) and decayed and filled surfaces (DFS) scores and (c) number
of teeth present using 11-year data from the representative popula-
tion-based cohort, Study of Health in Pomerania (SHIP).
2 | MATERIAL AND METHODS
2.1 | Study population
The study sample was obtained from the ongoing prospective cohort
study (SHIP), which adapted a two-stage cluster design (Keil et al.,
1988). The cohort was initiated in 1997–2001 (SHIP-0) and was fol-
lowed up after 5 (SHIP-1), 11 (SHIP-2) and 16 years (SHIP-3) (Völzke
et al., 2011). Since information about the PTB usage was not avail-
able in SHIP-0, we considered the data from SHIP-1 as baseline ex-
amination and SHIP-2 and SHIP-3 as the 6- and 11-year follow-ups,
respectively. Participants with information on exposure, outcomes
and covariates within at least one examination were included in the
study. The study started with a sample of 3,300 participants at base-
line. The flow of study participants in the study is shown in Figure 1.
The study protocol was approved a priori by the ethics committee of
the University of Greifswald, and written informed consent for the
interviews, clinical and dental examinations was obtained from all the
2.2 | Dental examination
Dental examinations were performed by calibrated and licensed
dentists. Initial training was conducted by a periodontist (TK). The
intra-rater and inter-rater reliability values are shown in Table S1.
Identical recording protocols were used for all time points. From the
dental examination, number of teeth present (full mouth), PD, CAL,
DMFS score and DFS score were calculated. Detailed information on
the dental examination can be found in the supplementary material.
2.3 | Interviews and medical examination
Trained and certified interviewers conducted computer-assisted per-
sonal interviews for participants during all the visits to collect informa-
tion on the exposure and covariates. Participants were asked whether
they used powered or manual toothbrush at each time point from
SHIP-1 to SHIP-3. Based on the toothbrushing frequency, participants
times/day). Classification of covariates considered in the study (educa-
tional status at the start of study, smoking status, toothbrushing fre-
quency, dental visit in the last 12 months, periodontal treatment in the
last 5 years, diabetes, physical activity and Centers for Disease Control
and Prevention/American Academy of Periodontology (CDC/AAP)
case definition of periodontitis) are mentioned in Table 1. Body mass
index (BMI) was calculated as weight in kg/(height in m)2. At baseline
(SHIP-1), known diabetic cases, defined as diagnosed cases accord-
ing to self-reported physician's diagnosis or treatment with anti-dia-
betic drugs (Anatomical Therapeutic Chemical Classification System
code A10), were recorded. Prevalent cases based on information
from SHIP-0 were combined with incident cases between SHIP-0 and
SHIP-1. Blood samples were drawn at non-fasting status to determine
HbA1c levels using HPLC method (Bio-Rad Diamat, Munich, Germany).
Scientific rationale for the study: Powered toothbrushes
have been in the market for quite a long time and, their
effectiveness has been shown in a number of clinical or
observational studies. However, long-term effectiveness
of powered toothbrushes in a population-based study has
never been performed.
Principal findings: Powered toothbrush users had reduced
progression of probing depths and clinical attachment loss.
On the long run, this has been translated into retaining
more number of teeth.
Practical implications: Powered toothbrush seems to be
an effective (preventive) tool in maintaining oral hygiene.
Therefore, dental practitioners might recommend its usage.
PITCHIK A eT Al.
2.4 | Statistical analyses
All analyses were performed using Stata/SE 14.2 (StataCorp 2015,
College Station, T X, USA). The following time-varying outcomes were
considered: (a) mean PD, (b) mean CAL, (c) DMFS, (d) DFS and (e)
number of teeth present. Continuous and categorical variables were
compared using Student's t test and chi-square test, respectively. To
assess the longitudinal effects of PTB usage on different outcomes,
mixed-effects linear regression models over three time points were
constructed for each outcome using the entire sample. The time
variable was divided by 11, to obtain estimates that reflect the ef-
fect of PTB usage 11 years from baseline, which was the time span
between SHIP-1 and SHIP-3. All covariates were selected a priori,
based on the clinical knowledge. Models were constructed with sub-
ject ID and time as random intercept and slope, respectively, so that
they took into effect the repeated measurements within subjects at
different follow-ups, which denote the multiple levels. The advantage
with mixed-effects modelling approach is that it requires complete
datasets at each follow-up separately, but not across examinations.
All models were adjusted for baseline (SHIP-1) covariates, such as
age, sex, BMI, education, smoking, diabetic status, HbA1c values,
frequency of toothbrushing and history of dental visit in the last
12 months. Physical activity was included as additional covariate in
the number of teeth present models. Mean PD and CAL models were
additionally adjusted for physical activity and history of periodontal
treatments during the past 5 years; but the random slope was ex-
cluded as the models did not converge. Age was included in the model
as a restricted cubic spline with three knots. The adjusted estimates
(β), 95 confidence intervals (95% CI) and their corresponding p-values
were calculated. After obtaining the adjusted estimates, percentage
change for MTB and PTB users after 11 years of follow-up time was
calculated using the formula ((βPTB−βMTB)/βMTB)*100 (United States
FIGURE 1 Overview of the flow of
study participants in the study
PITCHIKA eT Al .
Census Bureau, 2015). p-Values < 0.05 were considered as indicator
of statistical significance.
Analyses were restricted to the following subsets: (a) regular
brushers (n = 2,464 at SHIP-1), (b) younger subjects (25–55 years,
n = 1,617) and (c) younger regular brushers (n = 1,403). After ini-
tial analyses, participants were stratified based on the CDC/AAP
case definition of periodontitis to observe if the severity of peri-
odontal disease had an influence on the association with PTB, and
all models were repeated. Furthermore, sensitivity analyses were
performed on the entire sample models by including subjective
influence on oral hygiene, inter-dental aids usage, screening for
preventive medicine and cancer or preventive dental screening
(Table S5). Additionally, to avoid over-adjustment, we performed
directed acyclic graphs (DAGs) for each outcome spectrum
(periodontitis, caries and no. of teeth present) (Textor, Hardt,
& Knüppel, 2011). DAGs for each outcome resulted in adjusting
for age, sex, education, toothbrushing frequency, dental visit in
the last 12 months and history of periodontal treatment within
the last 5 years (Figure S1). Thereafter, models were constructed
adjusting for these variables under each outcome. The recom-
mendations of the Strengthening the Reporting of Observational
Studies in Epidemiology (STROBE) guidelines for observational
studies were applied for reporting (von Elm et al., 2014).
3 | RESULTS
3.1 | Baseline characteristics
A total of 2,819 participants with mean age of 52.1 ± 14.4 years were
included in the model (Table 1). PTB users were younger (46.3 years)
than the MTB users (53.4 years). PTB users fared well in education,
toothbrushing frequency, dental visit in the last 12 months, diabetic
TABLE 1 Baseline characteristics (SHIP 1) for participants present in the final model
Variable Group Tot al MTB user PTB user p‐value
Sample size for SHIP 1 in model 2,819 2,304 515 –
Age (in years) – 52.1 ± 14.4 53.4 ± 14. 5 46.3 ± 12.4 <0.001**
Sex Male 1,353 (48.0) 1,156 (50.2) 197 (38.3) <0.001*
Female 1,466 (52.0) 1,14 8 (49. 8) 318 (61.7 )
Education <10 years 868 (30.8) 788 (34.2) 80 (15.5) <0.001*
10 years 1,408 (50.0) 1,10 3 (47.9) 305 (59.2)
>10 ye ars 543 (19.2 ) 413 (17.9) 130 (25.3)
Smoking status Non-smoker 1,207 (42.8) 999 (43.4) 208 (40.4) 0.36*
Former smoker 870 (30.9) 710 (30.8) 160 (31.1)
Occasional smoker 97 (3.4) 74 (3.2) 23 (4.4)
Current smoker 645 (22.9) 521 (22.6) 124 (24.1)
Toothbrushing frequency Irregular brushers 442 (15.7) 391 (17.0) 51 (9.9) <0.001*
Regular brushers 2,377 (84.3) 1,913 (83.0) 464 (90.1)
Dental visit in the last 12 months No 20 0 (7. 1) 176 ( 7.6) 24 (4.6) 0.02*
Yes 2,619 (92 .9) 2,128 (92.4) 491 (95.4)
Periodontal treatment in the last
No 2, 513 (89. 2) 2,076 (90.1) 437 (85.0) 0.002*
Yes 304 (10.8) 227 (9.9) 77 (15.0)
Diabetes No 2,568 (91.1) 2,090 (90.7) 478 (92.8) 0.13*
Yes 251 (8.9) 214 ( 9.3) 37 (7. 2)
HbA1c (in %) - 5.4 ± 0.8 5.4 ± 0.8 5.2 ± 0.8 <0.001**
BMI (in kg/m2) - 27.8 ± 4.8 27.9 ± 4.8 27. 0 ± 4.9 <0.001**
Physical activity <1 hr sport/week 1,784 (63.3) 1,510 (65. 6) 274 (5 3. 2) <0.001*
1–2 hr sport/week 490 (17.4) 381 (16.5) 109 (21.2)
>2 hr sport/week 545 (19. 3) 413 (17.9) 132 (25.6)
CDC/AAP case definition No/mild periodontitis 1,187 (48 .3) 885 (44.7) 302 (63.2) <0.001*
Moderate periodontitis 877 (35.7) 740 (37.3) 137 (28.7)
Severe periodontitis 395 (16.0) 356 (18.0) 39 (8.1)
Note: Data are presented as mean ± standard deviation or number (column percentages).
Abbreviations: MTB: manual toothbrush; PTB: powered toothbrush; BMI: body mass index; CDC/AAP: Centers for Disease Control and Prevention/
American Academy of Periodontology.
*p-Values were obtained using chi-square test for categorical variables. **p-Values were obtained using Student's t test for continuous variables.
Bold numbers indicate statistically significant effect (p-Value < 0.05).
PITCHIK A eT Al.
status, BMI and physical activity. PTB usage in our study had increased
over time [SHIP-1: 515 (18.3%); SHIP-2: 540 (27.3%); SHIP-3: 543
(36.9 %)].Comp ar edto MT Bu ser s, PT Bu ser sh ad lo we rm ea nP D,me an
CAL, DMFS and DFS scores while having more teeth present (Table 2).
3.2 | Association between PTB usage and
After adjustment, PTB usage was significantly associated with re-
duced mean PD and mean CAL progression in the entire sample as
well as all subsets (Table 3). “PTB usage” denotes the effect of PTB
usage on dependent variable for time = 0 (baseline/SHIP-1). Time
(per 11-year increase) reflects the rate of change in MTB users over
11-year follow-up (SHIP-3). Interaction denotes exposure-depend-
ent (PTB vs. MTB) difference in the rates of change over 11-year
follow-up period. For example, in the entire sample, PTB users
had −0.0 3 mm smaller mean PD th an MTB brushers at ba seline.
However, after 11 years, MTB users had 0.41 mm of mean PD pro-
gression, while the PTB users had 0.09 mm significantly less mean
PD, that is 0.32 mm mean PD progression. This difference could also
be translated as PTB users having 22% less mean PD progression
over a period of 11 years (Figure 2 and Table S2). On exploring the
subsets of study participants, PTB users had a significantly low mean
PDprogressions(estimates rangingfrom −0.09to −0.11).Similarly,
PTB usage was associated with low mean CAL progression in the en-
ranging f rom −0.19 to −0.26). On s tratif ying the stu dy populat ion
based on the CDC/AAP definition (Table 4 and Figure 2), PTB usage
in the entire sample and regular brushers was associated with less
mean PD progression among subjects with no/mild and moderate
periodontitis, and less mean CAL progression in subjects with mod-
erate periodontitis only. Subjects with severe periodontitis did not
benefit from the usage of PTB.
3.3 | Association between PTB usage and caries
With respect to caries, PTB users had lower DMFS and DFS scores
throughout the study period (Table 2). On further exploring the data
after adjustment (Table 3), PTB users in the entire sample and in the
regular brushers’ subset had 1.32 surfaces (half-mouth) less DMFS
progression, corresponding to 17.7% significantly less DMFS pro-
gression than the MTB users; but this association was not present
among other subsets of participants. PTB usage had no influence on
the DFS scores (Table 3), even after stratifying the subjects based on
CDC/AAP definition (Table S3).
3.4 | Association between PTB usage and
number of teeth present
PTB users also had significantly less number of teeth lost over 11-year
follow-up, indirectly leading to more number of teeth present (Table 2).
After adjustment, reduction in the number of teeth present was about
Outcome Examination (N)
Mean ± SD
Tot al MTB user PTB user p‐Valuea
Mean PD SHIP-1 (2,616) 2.31 ± 0.71 2.34 ± 0.76 2.13 ± 0.57 <0.001
SHIP-2 (1,847) 2.64 ± 0.58 2.69 ± 0:60 2.52 ± 0:51 <0.001
SHIP-3 (1,372) 2.49 ± 0.59 2.55 ± 0.65 2.38 ± 0.45 <0.001
Mean CAL SHIP-1 (2,482) 2.23 ± 1.72 2.38 ± 1.78 1.62 ± 1.31 <0.001
SHIP-2 (1,758) 2.85 ± 1.53 3.02 ± 1.62 2.44 ± 1.20 <0.001
SHIP-3 (1,294) 2.54 ± 1.45 2.76 ± 1.59 2.21 ± 1.13 <0.001
DMFS SHIP-1 (2,787) 33.1 ± 16.4 34.1 ± 16.7 28.6 ± 14.3 <0.001
SHIP-2 (1,925) 34.6 ± 15.8 36.0 ± 16.2 30.8 ± 14.0 <0.001
SHIP-3 (1,417) 36.0 ± 15.8 38.1 ± 16.4 32.6 ± 14.3 <0.001
DFS SHIP-1 (2,709) 32.5 ± 16.2 33.4 ± 16.5 28.6 ± 14.3 <0.001
SHIP-2 (1,902) 34.3 ± 15.7 35.8 ± 16.2 30.7 ± 14.0 <0.001
SHIP-3 (1,417) 36.0 ± 15.8 38.1 ± 16.4 32.6 ± 14.3 <0.001
No. of teeth
SHIP-1 (2,819) 19.9 ± 7.5 19.2 ± 7.8 23.1 ± 5.0 <0.001
SHIP-2 (1,975) 20.0 ± 7.6 18.9 ± 8.1 22.9 ± 4.9 <0.001
SHIP-3 (1,471) 20.1 ± 7.6 18.5 ± 8.4 22.8 ± 5.0 <0.001
Note: Data are presented as mean ± standard deviation.
Abbreviations: MTB: manual toothbrush; PTB: powered toothbrush; PD: probing depth, CAL: clini-
cal attachment loss, DMFS: decayed, missing, filled surfaces; DFS: decayed, filled sur faces.
ap-Values were obtained using Student's t test.
Bold numbers indicate statistically significant differences (p < 0.05). Mean values do not allow
directly comparing the time course of the variables, since the three follow-ups are not identical in
terms of included SHIP participants.
TABLE 2 Distribution of dental
variables in participants included in the
models, stratified by examination time
PITCHIKA eT Al .
20% lesser in PTB users, that is PTB users retained on average 0.36
teeth more than their counterparts. Regularly brushing PTB users re-
tained 0.39 teeth more. On analysing the strata of study sample based
on CDC/AAP definition categories, PTB users in the entire sample with
no/mild periodontitis had 0.19 more teeth retained (Table S4).
4 | DISCUSSION
This study assessed the longitudinal association of PTB usage on peri-
odontit is, caries and num ber of teeth present f rom a prospective p opu-
lation-based cohort. Our main findings suggest that PTB usage over a
period of 11 year s had an effect i n reducing the pro gression of mean PD
and mean CAL in the study participants. This protective effect trans-
lated into more retained teeth in the whole cohort over the 11-year
study period. However, PTB usage did not influence caries (DFS) pro-
gression. These data circumvent the critique of the latest Cochrane re-
view on this subject: Empirical data on thresholds for clinically important
differences in plaque and gingivitis levels would help to determine whether
oral hygiene aids provide important health benefits (Yaacob et al., 2014).
Published short-term studies on PTB usage showed better plaque con-
trol and reduced gingivitis, but the present longitudinal study showed
for the first time that these effects are likely to get translated into re-
duced progression of PD and CAL. Also, more retained teeth speak in
favour of a clear tangible health benefit of PTB.
The main strength of the present study is that prospective data
from a population-based cohort with a follow-up time of 11 years
have been analysed. Our study had the benefit of extensive dental
data in terms of surface-level periodontal measures and caries data.
We identified and adjusted for commonly observed covariates such
as age, sex, BMI, education, smoking, diabetic status, HbA1c values,
toothbrushing frequency and history of dental visits, in addition to
periodontal treatment history and physical activity in some models.
Our study also had its share of limitations. It might be argued that
PTB users were younger in age, with better education, and oral health
awareness, in addition to having better physical activity. However, the
associations observed in this study were not lost even after adjusting
for all the relevant factors, although residual confounding cannot be
excluded. Furthermore, when the entire sample models were addi-
tionally adjusted for subjective influence on oral hygiene, inter-dental
TABLE 3 Results from mixed-effects linear models evaluating the effects of powered toothbrush usage on rates of change in oral health
β (95% CI)
Entire sample Regular brushers Younger subjects
Mean PDaPTB usage −0.03(−0.08;0.03) −0.03(−0.09;0.03) −0.02(−0.09;0.04) −0.02(−0.08;0.05)
Time (per 11-year increase) 0.41 (0.38; 0.45) 0.42 (0.38; 0.46) 0.42 (0.38; 0.47) 0.43 (0.39; 0.48)
Interaction −0.09 (−0.16; −0.02) −0.10 (−0.17; −0.02) −0.09 (−0.17; −0.01) −0.11 (−0.19; −0.02)
Mean CALaPTB usage 0.00(−0.11;0.11) −0.01(−0.13;0.10) 0.02(−0.10;0.14) 0.03(−0.10;0.15)
Time (per 11-year increase) 0.93 (0.86; 0.99) 0.93 (0.85; 1.00) 0.99 (0.91; 1.07) 1.00 (0.92; 1.09)
Interaction −0.19 (−0.32; −0.07) −0.19 (−0.33; −0.06) −0.23 (−0.38; −0.09) −0.26 (−0.41; −0.11)
DMFSbPTB usage 0.06(−0.67;0.79) 0.07(−0.69;0.83) 0.11(−0.69;0.92) 0.26(−0. 59;1.12)
Time (per 11-year increase) 7.4 3 (6 .97; 7. 89) 7. 51 ( 7.01 ; 8. 01) 6.84 (6.26; 7.42) 6.93 (6.30; 7.56)
Interaction −1. 32 (−2.18; −0.45) −1. 32 (−2.23; −0.41) − 0.73(−1.71;0.25) −0.78(−1.82;0.25)
DFSbPTB usage 0.41(−0.01;0.82) 0.37(−0.06;0.80) 0.35(−0.14;0.85) 0.36(−0.16;0.87)
Time (per 11-year increase) 3.68 (3.41; 3.94) 3.60 (3.32; 3.87) 3.78 (3.44; 4.13) 3.71 (3.34; 4.08)
Interaction −0.40(−0.89;0.10) −0.25(−0.76;0.26) −0.40(−0.99;0. 20) −0.29(−0.90;0.33)
No. of teeth
PTB usage −0.03(−0.24;0.18) −0.03(−0.25;0.19) −0.00(−0. 21;0.21) −0.05(−0.27;0.17)
Time (per 11-year increase) −1.86(−2.01;−1.72) −1.88(−2.03;−1.72) −1.38(−1.56;−1.21) −1.39(−1.58;−1.20)
Interaction 0.36 (0.11; 0.62) 0.39 (0.12; 0.66) 0.01(−0.25;0.27) 0.04(−0.23;0.31)
Note: All models were adjusted for baseline covariates, such as, age, sex, education, smoking, BMI, diabetic status, HbA1c values, toothbrushing fre-
quency and dental visits in the last 12 months. Subject ID and time were constructed as random intercept and slope, respectively. Number of teeth
present models were additionally adjusted for physical activity. Mean PD and mean CAL models were additionally adjusted for physical activity and
periodontal treatment within the last 5 years.
PTB usage: Effects of powered toothbrush usage on dependent variable for time = 0 (baseline/SHIP-1). Time (per 11-year increase): Rate of change
for manual toothbrush user over 11-year follow-up period. Interaction: Exposure-dependent (PTB versus MTB) difference in the rates of change over
11-year follow-up period.
Abbreviations: β: beta coefficient; 95% CI: 95% confidence interval; PD: probing depth; CAL: clinical attachment loss; DMFS: decayed, missing, filled
surfaces; DFS: decayed, filled surfaces.
aModels were performed without the inclusion of random slope.
bModels were performed with the inclusion of time per 11-year increase as a random slope.
Bold numbers indicate statistically significant effect (p-Value < 0.05).
PITCHIK A eT Al.
aids usage, screening for preventive medicine and cancer or preven-
tive dental screening, none of these variables failed to elicit significant
effect on the estimates. To avoid over-adjustment, based on the infor-
mation from DAGs, models were adjusted only for age, sex, education,
toothbrushing frequency, dental visits in the last 12 months and his-
tory of periodontal treatment within the last 5 years. This conserva-
tive approach did not alter any of our results (Table S6).
Periodontal and caries examinations were recorded using half-
mouth basis, which might not reflect the absolute values, although
it has less bias in comparison with full-mouth method (Tran et al.,
2016). Furthermore, caries was recorded only on cavitation level.
Leaving out non-cavitated caries lesions would have under-repre-
sented the caries burden in this study. Information on PTB usage
was obtained only through a simple question with binomial answer
possibility. In addition to usage of PTB in combination with MTB,
differentiation between different types of PTB, that is oscillatory
vs. vibratory, battery-powered vs. electric, sonic vs. ultra-sonic,
was not measured, especially when there were studies reporting
differences among them (Deacon et al., 2010; Rosema et al., 2016).
However, the differences between the different types of PTB
are not well studied, and more focus in this direction is needed.
Because it is not plausible to perform a long-term randomized con-
trolled trial to test the effectiveness of PTBs over MTBs, evidence
from well-designed population-based cohorts/practice-based re-
search is relevant for the dental community.
Although the effectiveness of PTB on periodontitis has been
well documented in the literature (Forrest & Miller, 2004; de Jager,
Rmaile, Darch, & Bikker, 2017; Yaacob et al., 2014), the evidence
arriving from long-term studies is limited (Ainamo, Xie, Ainamo, &
Kallio, 1997; Dentino et al., 2002; Dörfer, Joerss, & Wolff, 2009;
Dörfer et al., 2016). In a 12-month longitudinal study, Ainamo et al.
(1997) found PTBs to be effective in controlling gingivitis in terms of
reducing bleeding on probing, but they were not significantly bet-
ter in removing plaque. Dörfer et al. (2016) performed a random-
ized study with the longest follow-up time of 3 years, in which they
did not find any significant differences in PD and CAL progression
between PTB and MTB users with pre-existing recessions >2 mm.
However, as shown in a recent meta-analysis (Yaacob et al., 2014),
the use of a PTB results in less supragingival plaque, which in con-
sequence prevents or decreases the magnitude of gingivitis. An im-
proved oral hygiene has an effect on preventing the transition from
gingivitis to periodontitis rather than the progression of periodontitis
(Hellström, Ramberg, Krok, & Lindhe, 1996; Ramseier et al., 2017;
Schätzle et al., 2004). In line with this observation, we could see that
PTB had a distinct effect in reducing the PD and CAL progression in
subjects affected with no/mild or moderate periodontitis, whereas
the subjects with severe periodontitis did not benefit from the better
oral hygiene through PTB usage (Hellström et al., 1996). Although
the magnitude of change in PD and CAL among subjects with severe
periodontitis was in line with the moderate periodontitis subjects,
the effects were not significant, presumably due to the reduced sam-
ple size. Furthermore, it could be observed that the mean age of the
PTB users was significantly lower than the MTB users. In addition to
oral hygiene, progression of the periodontal disease in elderly people
is influenced by many other factors (Lamster, 2016), which might not
be counteracted by toothbrushing alone. Ramseier et al. (2017) con-
cluded from the 40-year results of the Sri Lanka study that gingivitis
control in young subjects is essential in preventing progression of
FIGURE 2 Percentage differences between the rates of change for powered toothbrush users in comparison with manual toothbrush
users. (a) Percentage change for powdered toothbrush users in entire sample and different subsets (regular brushers, younger subjects and
younger regular brushers) analysed. (b) Percentage change for powdered toothbrush users in entire sample stratified based on the CDC/AAP
definition of periodontitis (No/mild, moderate and severe)
PITCHIKA eT Al .
periodontitis, further loss of attachment and ultimately tooth loss.
Our data may be interpreted that subjects using a PTB experience
less attachment loss, which after 11-year follow-up resulted on av-
erage 0.36 more teeth than the MTB users. Furthermore, subjects
with no/mild periodontitis had 0.19 more teeth retained than their
To our knowledge, the number of studies assessing the rela-
tionship between caries and PTB is rare. In an interventional study
among drug-induced xerostomia patients (N = 80) with a follow-up
time of 1 year, Papas et al. (2007) recorded a significant reduction of
root caries among PTB users. Willershausen and Watermann (2001)
performed an interventional study (N = 40) with a 3-year follow-up
on elementary school children, but did not observe any benefit of
PTB on caries prevalence. A systematic review conducted on seven
studies assessing influence of oral hygiene in the absence of fluo-
ride on dental caries concluded “Personal oral hygiene in the ab-
sence of fluorides has failed to show a benefit in terms of reducing
the incidence of dental caries” (Hujoel, Hujoel, & Kotsakis, 2018).
In line with this argumentation, lack of association between PTB
usage and DFS seems plausible. However, PTB usage was associ-
ated with less DMFS progression, and this was due to the influence
from the M-component, which is a predominant feature in the el-
There has been a significant association of PTB usage with more
number of teeth retained in the entire sample and in the regular
brushers’ subset. Based on this, it is evident that the PTB usage on the
long run helps in preventing tooth loss and maintaining the number
of teeth in the oral cavity. From this study, it could be seen that the
TABLE 4 Results from mixed-effects linear models evaluating the effects of powered toothbrush usage on rates of change in
periodontitis models stratified by CDC/AAP definition
β (95% CI)
Entire sample Regular brushers Younger subjects
CDC/AAP definition = no/mild periodontitis
Mean PDaPTB usage −0.00(−0.05;0.04) 0.01(−0.04;0.06) 0.01(−0.11;0.13) 0.03(−0.09;0.16)
Time (per 11-year increase) 0.42 (0.38; 0.45) 0.43 (0.39; 0.47) 0.37 (0.30; 0.45) 0.40 (0.32; 0.48)
Interaction −0.06 (−0.13; −0.00) −0.08 (−0.14; −0.01) −0.05(−0.22;0.12) −0.08(−0.26;0.10)
Mean CALaPTB usage −0.02(−0.11;0.07) 0.01(−0.09;0.10) 0.06(−0.21;0.33) 0.10(−0.19;0.39)
Time (per 11-year increase) 0.82 (0.75; 0.89) 0.83 (0.75; 0.91) 0.67 (0.50; 0.83) 0.73 (0.55; 0.92)
Interaction −0.07(−0.19;0.06) −0.09(−0.22;0.04) −0.09(−0.47;0.29) −0.15(−0.55;0.25)
CDC/AAP definition = moderate periodontitis
Mean PDaPTB usage 0.04(−0.04;0.13) 0.05(−0.04;0.14) −0.04(−0.17,0.09) −0.05(−0.18;0.09)
Time (per 11-year increase) 0.27 (0.22; 0.33) 0.28(−0.22;0.34) 0.29 (0.21; 0.36) 0.28 (0.20; 0.37)
Interaction −0.16 (−0.27; −0.05) −0.17 (−0.29; −0.05) −0.04(−0.21;0.13) −0.05(−0.23;0.13)
Mean CALaPTB usage 0.04(−0.12;0.21) 0.03(−0.14;0.20) 0.00(−0.25;0.25) −0.04(−0.30;0. 22)
Time (per 11-year increase) 0.64 (0.55; 0.74) 0.65 (0.55; 0.76) 0.63 (0.50; 0.76) 0.61 (0.47; 0.75)
Interaction −0.32 (0. 51; −0.12) −0.33 (−0.54; − 0.13) −0.17(−0.46;0.12) −0.17(−0.48;0.14)
CDC/AAP definition = severe periodontitis
Mean PDaPTB usage −0.0 0(−0.23;0.23) −0.03(−0. 28;0.22) 0.10(−0.24;0.45) − 0.01(−0.38;0.36)
Time (per 11-year increase) 0.36 (0.23, 0.49) 0.36 (0.22; 0.51) 0.41 (0.24; 0.58) 0.40 (0.22; 0.59)
Interaction −0.22(−0.52;0.08) −0.19(−0.52;0.13) −0.45(−0.93;0.03) −0.31(−0.81;0.19)
Mean CALaPTB usage −0.09(−0. 50;0.32) −0.06(−0.48;0.37) −0.21(−0.85;0.43) −0.27(−0.92;0.37)
Time (per 11-year increase) 1.13 (0.92; 1.35) 1.12 (0.89; 1.35) 1.09 (0.80; 1.38) 1.06 (0.76; 1.35)
Interaction −0.30(−0.81;0.21) −0.35(−0.88;0.18) −0.65(−1.50;0. 20) −0. 59(−1.40;0.22)
Note: All models were adjusted for baseline covariates, such as, age, sex, education, smoking, BMI, diabetic status, HbA1c values, toothbrushing
frequency, dental visit in the last 12 months, physical activity and history of periodontal treatment in the last 5 years. Subject ID was constructed as
Abbreviations: β: beta coefficient; 95% CI: 95% confidence interval. CDC/AAP: Centers for Disease Control and Prevention/American Academy of
Periodontology. PD: probing depth; CAL: clinical attachment loss; DMFS: decayed, missing, filled surfaces; DFS: decayed, filled surfaces. PTB usage:
Effects of powered toothbrush usage on dependent variable for time = 0 (baseline/SHIP-1). Time (per 11-year increase): Rate of change for manual
toothbrush user over 11-year follow-up period. Interaction: Exposure-dependent (PTB versus MTB) dif ference in the rates of change over 11-year
aModels were performed without the inclusion of random slope.
Bold numbers indicate statistically significant effect (p-Value < 0.05).
PITCHIK A eT Al.
PTB usage may have a long-term protective effect on the oral health
in general. It could also be seen that there has been a gradual increase
in the usage of PTB over time. The reasons for this might be increased
advertisements and dentist recommendations. German Oral Health
Study showed that recently there has been an increase in the usage of
inter-dental cleaning aids (Jordan & Micheelis, 2016). This, in addition
to increased PTB usage as observed in the SHIP cohort, reflects the
increased awareness of German population towards oral hygiene.
5 | CONCLUSION
From the results in this study, it could be seen that the PTB usage
has a long-term protective effect on the oral health in terms of re-
duced probing depths, clinical attachments and number of teeth los t.
Based on this, it seems that the PTB usage in the long run helps in
maintaining the number of teeth in the oral cavity and reducing the
progression of periodontal disease burden.
The authors thank the study participants and all contributions to the
SHIP data collection by dental and medical examiners, technicians,
interviewers and assistants.
CONFLICTS OF INTERESTS
Prof. Dr. Thomas Kocher had received grants from Procter and
Gamble Co. to pay the salary for a scientist for 6 months, which did
not have any influence on the study design, data analysis and inter-
pretation of the results. The authors declare no potential conflicts of
interest with respect to the authorship and publication of this article,
and this includes financial interests.
Vinay Pitchika https://orcid.org/0000-0001-6947-2602
Christiane Pink https://orcid.org/0000-0001-5950-2716
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Additional supporting information may be found online in the
How to cite this article: Pitchika V, Pink C, Völzke H, Welk A,
Kocher T, Holtfreter B. Long-term impact of powered
toothbrush on oral health: 11-year cohort study. J Clin
Periodontol. 2019;00:1–10. https ://doi.org/10.1111/