The efficacy of an oscillating‐rotating power toothbrush compared to a high‐frequency sonic power toothbrush on parameters of dental plaque and gingival inflammation: A systematic review and meta‐analysis

Eveline van der Sluijs; Dagmar Else Slot; Nienke Lisette Hennequin‐Hoenderdos; Cees Valkenburg; Fridus (G A) van der Weijden

doi:10.1111/idh.12597

. 2022 Jun 25;21(1):77–94. doi: 10.1111/idh.12597

The efficacy of an oscillating‐rotating power toothbrush compared to a high‐frequency sonic power toothbrush on parameters of dental plaque and gingival inflammation: A systematic review and meta‐analysis

Eveline van der Sluijs ^1,^✉, Dagmar Else Slot ¹, Nienke Lisette Hennequin‐Hoenderdos ¹, Cees Valkenburg ¹, Fridus (G A) van der Weijden ¹

PMCID: PMC10084121 PMID: 35535635

Abstract

Aim

To establish the efficacy of oscillating‐rotating power toothbrush (OR‐PTB) compared to high‐frequency sonic power toothbrush (HFS‐PTB) on improving parameters of plaque and gingival inflammation. Safety and participants' preference were secondary interests.

Materials and methods

MEDLINE‐PubMed and Cochrane‐CENTRAL databases were searched, up to April 2021. Inclusion criteria were (randomized)controlled clinical trials that evaluated healthy humans brushing with an OR‐PTB compared to a HFS‐PTB. Evaluation for a minimum of 4 weeks, of one or more of the following parameters: plaque index scores (PI), bleeding scores (BS), number of bleeding sites (NoB) and gingival index scores (GI).

Results

Thirty two publications involving 38 comparisons were included after the independent screening. The descriptive analysis showed that in 54% of the comparisons, a significant difference in favour of the OR‐PTB was found for PI, BS and GI scores. The Quigley and Hein index showed a significant difference of means (DiffM) between the end scores (DiffM 0.13, 95% CI [0.05;0.21] p < 0.001), as well as for the Rustogi‐modified Navy index (DiffM 0.01, 95% CI [0.01;0.03] p = 0.002). This is in line with the meta‐analysis for BS (DiffM 0.09, 95% CI [0.03;0.14] p = 0.003), for which the results were in favour of the OR‐PTB and considered potentially clinically relevant. NoB showed a significant difference in favour of the OR‐PTB for the end scores (DiffM 3.61, 95% CI [2.63;4.58] p < 0.00001). No difference in safety was indicated, 78% of participants preferred the OR‐PTB.

Conclusion

For patients to maintain good plaque control and improve gingival health, there is a small but significant difference based on longer‐term studies between OR‐PTB and HFS‐PTB. This difference is potentially clinically relevant.

Keywords: dental plaque, gingival health, oscillating‐rotating toothbrush, power toothbrush, sonic toothbrush, systematic review

1. INTRODUCTION

There is general agreement that the greatest contributor to oral health is regular and thorough dental plaque removal, typically by means of a toothbrush. ¹ Toothbrushes are available in many different designs, varying in the shape of the handle, brush head, arrangement of bristles and filament shapes. The brush head in particular is continuously under revision in order to improve effectiveness. Powered toothbrushes (PTBs) have been in use since the 1940s, starting with devices with a circular brush head or a rectangular\brush head. Today PTBs are widely used and demonstrate benefits with regard to reducing dental plaque and gingivitis in comparison to manual toothbrushes (MTBs) in both short‐ and long‐term observations. ² Because of this cleaning performance and ease of use, PTBs are becoming increasingly accepted. ³ Several types of PTBs with different brush head configurations and modes of actions are available on the market. The high‐frequency sonic power toothbrush (HFS‐PTB) with a side‐to‐side bristle movement and the oscillating‐rotating power toothbrush (OR‐PTB) are the most retailed and researched modes of action worldwide.

Almost a decade ago, a solid Cochrane systematic review ³ conducted a direct comparison between PTBs with different modes of actions in regards to plaque and gingivitis reduction. At that time, no definitive conclusions could be drawn regarding the superiority of one type of PTB over another. A network meta‐analysis was recently published on the effects of OR‐PTBs, HFS‐PTBs and MTBs. The meta‐analysis was limited to randomized control trial (RCT) studies with a duration of up to 3 months in the period 2007–2017 and available in the database of a PTB manufacturer. ⁴ The analysis ultimately recommended that patients with various degrees of gingival bleeding use OR‐PTBs over HFS‐PTBs to improve plaque control and parameters of gingival inflammation. ⁴ Another systematic review compared PTBs to MTBs for oral health with no limitation to study duration. This review concluded that a PTB is more effective in reducing dental plaque, gingivitis and bleeding compared with a MTB. ⁵ Based on studies solely from the last decade, a recent systematic review further concluded that there is some evidence to suggest that OR‐PTBs might remove more plaque and reduce the number of bleeding sites better than other PTBs, including HFS‐PTBs. ⁶ Based on single brushing exercises, recent evidence also indicates that the use of OR‐PTBs results in a larger reduction of plaque scores than the use of HFS‐PTBs. ⁷ The authors of the study, with moderate certainty, recommended a OR‐PTB over a HFS‐PTB. However, the authors noted that the clinical relevance of the observed difference deserved further evaluation in longer‐term studies.

All other recent systematic reviews ⁶ , ⁷ on this topic were characterized by various restrictions, such as a specific research design, ⁷ year of publication, ⁶ or manufacturer database. ⁴ Therefore, based on that and the suggestion of a SR for long‐term studies there is a need for a SR that included and updates the findings of the dated Cochrane systematic review Deacon et al. (2010) ³ with respect to the comparison of OR and HFS‐PTB. Thus, the aim of this systematic review is to evaluate direct comparisons of the oscillating‐rotating power toothbrush versus high‐frequency sonic power toothbrush mode of action with respect to parameters of plaque and gingival inflammation using data from studies with a minimum duration of 4 weeks. The recommendations that emerge from this review may guide dental care professionals in providing evidence‐based advice concerning power toothbrush use to their patients.

2. MATERIALS AND METHODS

The systematic review and meta‐analyses in this study were prepared and reported in accordance with the Cochrane Handbook for Systematic Reviews of Interventions. ⁸ In addition, this research adhered to the guidelines of Transparent Reporting of Systematic Reviews and Meta‐analyses ⁹ , ¹⁰ and Assessing the Methodology Quality of Systematic Reviews. ¹¹ , ¹²

The protocol for this systematic review was developed a priori and registered with the International Prospective Register of Systematic Reviews ¹³ under registration number CRD42020161883.

2.1. Focused questions

The questions that guided the systematic review, which is focused on healthy participants, were the following.

Primary question:

What is the efficacy of oscillating‐rotating power toothbrush compared to high‐frequency sonic power toothbrush in improving parameters of dental plaque and gingival inflammation?

Secondary questions:

What is the safety of oscillating‐rotating power toothbrush compared to high‐frequency sonic power toothbrush for oral soft tissues and hard tissues?
What are participants' preferences between oscillating‐rotating power toothbrush and high‐frequency sonic power toothbrush?

2.2. Search strategy

For the comprehensive search strategy that was in place through April 2021, three electronic databases were utilized to search for appropriate papers that satisfied the study purpose. The National Library of Medicine, Washington, D.C. (MEDLINE‐PubMed) and the Cochrane Central Register of Controlled Trials (CENTRAL) were used to identify eligible publications. Table 1 presents the search strategy, including the search terms. All references cited in the papers that were selected for this review were scrutinized to identify additional relevant studies. Further hand searching was not performed other than as part of the Cochrane Worldwide Hand Searching Program and uploaded to CENTRAL.

TABLE 1.

Search terms used for the search strategy

The following strategy was used in the search: {(intervention) AND (specification)}
{(<Intervention:>
Toothbrush* OR ‘Toothbrushing’[Mesh])
AND
(<specification:>
power* OR electric*)}

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Note: The asterisk (*) was used as a truncation symbol.

2.3. Screening and selection

Two reviewers (NLHH and EvdS) screened the titles and abstracts of publications obtained from the search process using the Rayyan web application. ¹⁴ , ¹⁵ Possible duplicates were flagged and checked by the two reviewers to eliminate identical studies. Disagreements in the screening and selection process were resolved by consensus or, if disagreement persisted, by arbitration through a third reviewer (DES). The reviewers read titles and abstracts in detail to screen for suitability and categorized them as included, excluded or undecided. Once the list of included titles and abstracts was obtained, full‐text versions of the papers were retrieved and screened for suitability. After the independent screening process, the search was unblinded and the ‘conflicts’ that were identified by Rayyan were resolved by the reviewers. The reviewers worked independently and were blinded from each other's results during the screening process.

The eligibility criteria for published studies were the following:

Publications written in the English language.
(Randomized) controlled clinical trials (CCT or RCTs).
Studies conducted on humans who met the following conditions:
- ≥18 years old
- In good general health, which means having no systemic disorders
- Participant brushing
- Without an orthodontic fixed appliance
Study duration of a minimum of 4 weeks.
Intervention: A high‐frequency sonic power toothbrush (HFS‐PTB) with a side‐to‐side bristle movement.
Comparison: An oscillating‐rotating power toothbrush (OR‐PTB). Only power toothbrushes with a rechargeable battery and a handle containing a motor that provides mechanical movement to a brush head with filaments. ¹⁶
Primary parameters of interest: Plaque index scores (PI), bleeding scores (BS), number of bleeding sites (NoB), gingival index scores (GI).
Secondary parameters of interest: Oral soft tissue assessments (OST), gingival abrasion scores (GA), adverse events (AE) and/or panellist questionnaires.

2.4. Assessment of heterogeneity

The heterogeneity of the primary outcome parameters across publications was detailed according to the following factors:

Study design and participant characteristics.
Study procedures and products.
Plaque and gingivitis indices and their modifications.

To evaluate methodological heterogeneity, the study designs and toothbrushing regimens were evaluated. When clinical or methodological heterogeneity was considered to be high across publications, the sources of heterogeneity were explored by subgroup analyses and sensitivity analysis.

2.5. Risk of bias assessment and grading

Two reviewers (NLHH and DES) individually scored the methodological qualities and ethical aspects ⁷ of the included publications according to the method described in detail by Van der Weijden (2009) ¹⁷ and Keukenmeester et al. (2012). ¹⁸ When random allocation, defined eligibility criteria, masking of examiners, masking of participants, balanced experimental groups, identical treatment between groups (except for the intervention) and reporting of follow‐up were present, the study was classified as having an estimated low risk of bias. When one of these criteria was missing, the study was considered to have an estimated moderate risk of bias. When two or more of these criteria were missing, the study was estimated to have a high risk of bias. Disagreements in the quality assessments were resolved by consensus or, if disagreement persisted, by arbitration through a third reviewer (FvdW).

2.6. Statistical analyses

2.6.1. Data extraction

The data from the publications that met the selection criteria were extracted and processed for further analysis. Two reviewers (EvdS and NLHH) evaluated the selected publications for mean baseline, end and incremental difference scores and standard deviations (SDs). To ensure an accurate estimate, any data approximation in figures was avoided. Some of the studies provided a standard error (SE) of the mean. These values were converted to SDs based on the sample size (SE = SD/√N). Numbers with three digits were rounded to two digits. In cases of missing data or undetermined information, attempts were made to contact the first or corresponding author of the included publications for clarification or to retrieve additional data. For studies that had multiple treatment arms and for which data from the control group were compared with more than one other group, the number of participants (N) in the control group was divided by the number of comparisons. Disagreements in the data extraction were resolved by consensus or, if disagreement persisted, by arbitration through a third reviewer (DES).

2.6.2. Data analysis

Descriptive analysis

A descriptive data analysis was conducted for all included studies to summarize the results. The primary variables of interest were plaque index scores (PI), bleeding scores (BS) and/or gingival index scores (GI). The data were summarized and analysed using vote counting. ¹⁹ For the secondary parameters of interest, an overview was presented.

Meta‐analysis

When appropriate, a meta‐analysis was performed, and the difference of means (DiffM) was calculated using an inverse variance method (review manager 2014) in Review Manager [RevMan Version 5.3.Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2014] ²⁰ with either the fixed or random‐effects model, as appropriate. For the analysis, the assumption was made that summary data were missing at random, and therefore, all available data were included. The data were separated by the following primary indices: Modified Quigley and Hein Plaque index, ²¹ , ²² , ²³ Rustogi Modified Navy Plaque index, ²⁴ papillary bleeding index, ²⁵ angular bleeding Index/bleeding on marginal probing, ²⁶ , ²⁷ , ²⁸ NoB, gingival bleeding index, ²⁹ or the (modified) gingival index. ³⁰

Heterogeneity was tested using the chi‐square test and the I² statistic. ⁸ A chi‐square test resulting in a p‐value <0.1 was considered to be an indication of significant statistical heterogeneity. As an approximate guide for assessing the degree of inconsistency across studies, an I² statistic of 0%–40% was interpreted as might not be important, a statistic of 40%–60% indicated moderate heterogeneity, 60%–80% indicated substantial heterogeneity, and 80%–100% indicated considerable heterogeneity. ³¹

Publication bias

If the meta‐analysis comprised sufficient trials to make visual inspection of the plot meaningful (10 trials minimum), funnel plots were used for assessment of publication bias. The presence of asymmetry in the inverted funnel may suggest publication bias. ⁸ , ³²

Additional analysis

The Lan‐DeMets version ³³ of the O'Brien‐Fleming function ³⁴ was used for calculating the trial sequential monitoring boundaries (TSMBs). TSA software version 0.9.5.10 Beta (Copenhagen Trial Unit) was used. ³⁵ , ³⁶ , ³⁷ , ³⁸

Furthermore, distribution‐based methods were applied in order to determine the clinical relevance of the study results. ³⁹ , ⁴⁰ , ⁴¹ , ⁴² , ⁴³ , ⁴⁴ Using the distribution‐based method, the clinical relevance was scored as not clinically relevant, potentially clinically relevant or clinically relevant, based on the relationship among the mean difference of the variable, minimal important difference (MID) and effect size ⁴⁴ was interpreted as small, 0.50 (0.40–0.79) as medium and ≥0.80 as large. The MID was determined by multiplying the effect size of the difference between groups by the pooled baseline SD of the two groups. ³⁹ The MID was calculated by multiplying either 0.2 or 0.5 by the pooled baseline standard deviation. ⁴¹

Evaluation of the clinical relevance of the results on the variable plaque indices, BOP, MGI and GBI was performed based on the distribution‐based method using the ES, ³⁹ MID ³⁹ , ⁴⁵ and clinical judgement. ⁴²

2.7. Grading the body of evidence

The Grading of Recommendations Assessment, Development and Evaluation system, as proposed by the GRADE working group, was used to rank and grade the evidence emerging from this review. ⁴⁵ , ⁴⁶ Two reviewers (FvdW and DES) rated the certainty of the evidence as well as the strength and direction of recommendations according to the following aspects: risk of bias of the individual studies, consistency and precision among the study outcomes, directness of the study results and detection of publication bias. Any disagreement between the two reviewers was resolved after additional discussion with the third reviewer (EvdS).

3. RESULTS

3.1. Search and selection results

Figure 1 presents the search and selection results and the included publications. Among the unique titles and abstracts, there were 14 conflicts (<2%) scored by the reviewers. The comprehensive search of the databases resulted in 32 publications including 38 comparisons that were eligible for inclusion. ⁴⁷ , ⁴⁸ , ⁴⁹ , ⁵⁰ , ⁵¹ , ⁵² , ⁵³ , ⁵⁴ , ⁵⁵ , ⁵⁶ , ⁵⁷ , ⁵⁸ , ⁵⁹ , ⁶⁰ , ⁶¹ , ⁶² , ⁶³ , ⁶⁴ , ⁶⁵ , ⁶⁶ , ⁶⁷ , ⁶⁸ , ⁶⁹ , ⁷⁰ , ⁷¹ , ⁷² , ⁷³ , ⁷⁴ , ⁷⁵ , ⁷⁶ , ⁷⁷ , ⁷⁸

Search and selection results. (M)GI, Modified gingival index; (M)Q&H‐PI, modified Quigley & Hein plaque index; (R)MN‐PI, Rustogi Modification of the Navy plaque index; Ang/BOMP, Angular Bleeding index/ Bleeding on marginal probing; BI, Bleeding index; BS, Bleeding scores; GBI, Gingival bleeding index; MGI, Modified gingival Index; NoB, Number of bleeding sites

3.2. Study characteristics and heterogeneity assessment

Considerable heterogeneity was observed in the 32 papers with respect to study design; evaluation period; study population and number, gender and age of participants. With the exception of two comparisons ⁵¹ , ⁵⁸ that used a cross‐over design, all other included studies were RCTs and had a parallel design. Four comparisons ⁴⁸ , ⁵³ , ⁵⁴ , ⁵⁷ utilized a split‐mouth method in which one comparison ⁴⁸ selected two contralateral quadrants and the other three comparisons ⁵³ , ⁵⁴ , ⁵⁷ divided the dentitions into the left and the right side. The total study duration varied from 30 days to 6 months. The total number of participants ranged from 30–284. The approximate mean age of the 2805 participants was 40 and varied from 18–83 years old. Information regarding the study characteristics is provided in an overview in online Appendix S1A and in detail in online Appendices S1B,C.

3.3. Risk of bias assessment

The quality assessments including internal validity, external validity, statistical validity and clinical and ethical considerations are presented in the online Appendices S3A,B. The estimated potential risk of bias is moderate in one publication ⁶⁴ and low in the other 31 publications. ⁴⁷ , ⁴⁸ , ⁴⁹ , ⁵⁰ , ⁵¹ , ⁵² , ⁵³ , ⁵⁴ , ⁵⁵ , ⁵⁶ , ⁵⁷ , ⁵⁸ , ⁵⁹ , ⁶⁰ , ⁶¹ , ⁶² , ⁶³ , ⁶⁵ , ⁶⁶ , ⁶⁷ , ⁶⁸ , ⁶⁹ , ⁷⁰ , ⁷¹ , ⁷² , ⁷³ , ⁷⁴ , ⁷⁵ , ⁷⁶ , ⁷⁷ , ⁷⁸ Compared to the older studies, the five ethical aspects were more frequently reported in the publications from the last decade.

3.3.1. Ethical aspects

IRB approval was reported for all studies since 2002, with the exception of one study. ⁶⁴ From the same year onward, all participants provided written informed consent. The presence of a conflict of interest (COI) was reported in 16 out of 32 publications. ⁶⁰ , ⁶² , ⁶³ , ⁶⁴ , ⁶⁵ , ⁶⁷ , ⁶⁹ , ⁷⁰ , ⁷¹ , ⁷² , ⁷³ , ⁷⁴ , ⁷⁵ , ⁷⁶ , ⁷⁷ , ⁷⁸ Of the 16 publications, 10 publications disclosed a combination of non‐industry authors and industry‐related authors. ⁶⁰ , ⁶² , ⁶⁵ , ⁶⁷ , ⁶⁹ , ⁷² , ⁷⁴ , ⁷⁶ , ⁷⁷ , ⁷⁸ Only the non‐industry authors declared not having a COI. The source of funding was reported in 22 publications ⁴⁹ , ⁵³ , ⁵⁴ , ⁵⁶ , ⁵⁷ , ⁵⁹ , ⁶⁰ , ⁶¹ , ⁶² , ⁶³ , ⁶⁴ , ⁶⁵ , ⁶⁶ , ⁶⁷ , ⁶⁸ , ⁶⁹ , ⁷⁰ , ⁷¹ , ⁷² , ⁷³ , ⁷⁴ , ⁷⁵ , ⁷⁶ , ⁷⁷ , ⁷⁸ and of those, two publications ⁷⁰ , ⁷³ stated that products were supplied by one or more manufacturers.

3.4. Results of study outcomes

The online Appendices S4, S5 and S6 detail the results from the data extraction for the primary parameters of interest: PI, BS, PBI, GBI and the Modified Gingival Index scores (MGI).

3.4.1. Descriptive analysis

Tables 2 and 3 present an overview of the descriptive analysis of the 32 publications and 38 comparisons. Table 2 indicates statistical significance results of OR‐PTBs compared to HFS‐PTBs. The overall difference was significant in favour of the OR‐PTB in 54% of the comparisons that evaluated PI, 58% with respect to BS and 48% with respect to MGI scores. In total, 22 out of the 98 primary outcome parameters of interest indicated no difference between both toothbrushes (Details are shown in online Appendix S2). Table 3 presents an overview of the secondary parameters of interest. In the included studies, there was no difference between the toothbrushes with respect to safety (Online Appendices S7 and S8), and participants in seven out of the nine publications preferred the OR‐PTB (Online Appendix S9).

TABLE 2.

Overview of the descriptive summary of the 32 studies and 38 comparisons with the number and percentages of statistical significance of the OR‐PTB compared to the HFS‐PTB in numbers and percentages

Outcome	Number of comparisons	Significant difference in favour of the comparison (OR‐PTB)	Significant difference in favour of the intervention (HFS‐PTB)	No difference	Unknown (?)	Online appendix number
Plaque index scores	35	19 (54%)	3 (9%)	11 (31%)	2 (6%)	S2
Bleeding scores	38 ^a	22 (58%)	8 (21%)	4 (10.5%)	4 (10.5%)	S2
(modified) Gingival index scores	25	12 (48%)	5 (20%)	7 (28%)	1 (4%)	S2
Overall	98	53 (54%)	16 (16%)	22 (22%)	7 (7%)

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Abbreviations: HF‐PTB, High‐frequency sonic power toothbrush; OR‐PTB, Oscillating‐rotating power toothbrush.

^{^a}

Twelve comparisons evaluated two measures of bleeding scores.

TABLE 3.

Overview of the descriptive summary of safety assessments and panel list questionnaire comparing OR‐PTB with HFS‐PTB

Outcome	Number of publications	Number of publications and the result	Online appendix number
Intra‐oral safety assessments	23	15 No difference 8 Unknown	S7
Gingiva abrasion score	1	No difference between the products	NA
Adverse events	22	18 Reported no AE 10 Reported AE assessed as possibly related to the study product 1 Reported AE unrelated to the products	S8
Panellist questionnaire	9	5 Significant in favour of OR‐PTB 3 Numerically in favour for OR‐PTB 1 Unknown	S9

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Abbreviations: AE, Adverse Event; HFS‐PTB, High‐frequency sonic power toothbrush; NA, not applicable; OR‐PTB, Oscillating‐rotating power toothbrush.

3.4.2. Meta‐analysis

Primary outcomes

Tables 4, 5, 6, 7, 8, 9, 10 present an overview of the outcomes of the meta‐analysis, and the forest plots are displayed in online Appendices S10 to S16. The meta‐analysis was based on 16 comparisons using the modified Quigley and Hein Plaque index (MQHPI). The results revealed that the Difference of Means (DiffM) was significant (p < 0.001) in favour of the OR‐PTB for end scores (DiffM = 0.13, 95% CI [0.05; 0.21]) (Table 4). In addition, the (Rustogi) modified Navy Plaque index (RMNPI) demonstrated a statistically significant DiffM (p = 0.002) for the end scores (DiffM = 0.01 (95% CI [0.00; 0.03]) in favour of the OR‐PTB (Table 5).

TABLE 4.

Meta‐analysis for the modified Quigley and Hein Plaque index using a random model

Modified Quigley and Hein Plaque index	Number of comparisons	Comparison	Effect size			Heterogeneity		Online Appendix number
			DiffM	95% CI	p‐Value	I ²	p‐Value	Forrest plot	Funnel plot	TSA
			DiffM	95% CI	p‐Value	I ²	p‐Value	Forrest plot	Funnel plot	Number	TSA does research the RIS or not (yes/no)
Grossman et al. (1995) ⁴⁷ Robinson et al. (1997) ⁴⁹ Yankell & Emling (1997) ⁵⁰ Putt et al. (2001) ⁵³ Van der Weijden et al. (2002–1) ⁵⁴ Goyal et al. (2005) ⁵⁵ 2x Patters et al. (2005) ⁵⁶ Rosema et al. (2005) ⁵⁷ Williams et al. (2009) ⁶⁰ Büchel et al. (2014) ⁶⁵ Schmickler et al. (2016) ⁷⁰ 2x Schmalz et al. (2017‐AJD) ⁷¹ Schmalz et al. (2018‐COI) ⁷³ 2x	16	Baseline	−0.03	(−0.08; 0.02)	0.19	0%	0.95	S10A	S10B	NA	NA
		End	0.13	(0.05; 0.21)	<0.001	54%	0.008	S10C	S10D	S10E	Yes
		Difference	?	?	?	?	?	NA	NA	NA	NA

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Note: p‐Values are presented in bold if p ≤ 0.05.