Powered Toothbrushes: An Opportunity for Biofilm and Gingival Inflammation Control

The present review aimed at a broad investigation on the potential of powered as compared to manual toothbrushes in different aspects of clinical dentistry. Studies evaluating plaque and gingival inflammatory parameters were included, as well as those that investigated adverse effects. Emphasis was given separately to adults, youngsters, special-needs patients, and those under fixed orthodontic therapy. In general, comparisons favored powered toothbrushes. In summary, approximately 68% of the included studies, in terms of plaque/gingival inflammation in adults, presented better results for powered toothbrushes. In children and special-needs populations, approximately 40% of the included studies favored powered toothbrushes for plaque/gingival inflammation, and none favored manual ones. In orthodontic individuals, 50% of the studies also demonstrated a better effect of powered toothbrushes on plaque and gingival inflammation. All included studies that assessed adverse events did not demonstrate a difference in these effects when comparing manual vs. powered toothbrushes. It is concluded that the use of powered toothbrushes is an opportunity to enhance patterns of plaque control and associated gingival inflammation.


Introduction
Supragingival plaque control is one of the most beneficial preventive strategies in clinical dentistry. In accordance with individual needs, the dental practitioner is responsible for motivating and instructing the patient to carry out more effective plaque control, always minimizing adverse effects. Studies consistently demonstrate that individuals with good standards of oral hygiene standards and good professional maintenance of oral health have a lower incidence of dental caries, periodontal diseases, tooth loss, and as shown more recently, better outcomes with dental implants.
A classic study performed in Sweden by Axelsson et al. clearly demonstrated that a strict oral hygiene program results in long-term maintenance of the teeth with a lower incidence of caries and periodontal breakdown [1]. Other studies also have demonstrated similar findings [2,3]. Despite the well-established positive role of proper plaque control, optimal levels of oral hygiene are not observed in the population as a whole [4,5].
Manual toothbrushes are the instruments most widely used for the removal of plaque. Although initially developed for situations where manual toothbrushes are not effective, especially due to impairment of motor function, powered toothbrushes are currently used as an alternative to manual toothbrushes. 1 e industry has developed different types of powered toothbrushes, and this innovative technology has evolved very rapidly. In 1998, the European Workshop on Mechanical Plaque Control carefully reviewed the evidence supporting the use of powered toothbrushes. Its conclusions included the increased ability of powered toothbrushes to remove plaque from the interproximal area; the importance of professional motivation (reinforcement) to achieve optimal results with powered toothbrushes; the safety of powered toothbrushes regarding lack of adverse effects in terms of trauma; and superior efficacy of powered toothbrushes as compared to manual ones, as demonstrated in clinical trials. e panel also concluded that toothbrush design could have a role in these results [6]. e literature supporting the use of powered toothbrushes has continuously grown. Continuous updates are needed to keep up with research and development in this area. In the present study, a panel of experts from Brazil and Mexico sought to review the best available evidence on possible indications for powered toothbrushes in clinical dentistry as of December 2020.
is is not a systematic review, since there are multiple questions and interests. Rather, it is a narrative summary of the available, published evidence comparing manual and powered toothbrushes. e authors are aware that publication bias is present and that much of this body of evidence is industry-funded. It is also acknowledged that further research and development in healthcare technologies are of utmost importance.
To compile this evidence, a systematic search of the PubMed database, combining terms of interest for the present study to find all possible articles comparing manual and powered toothbrushes, was conducted. Different terms of interest were combined in each of the topics (always having the outcome and synonyms and the exposure-manual and electric toothbrushes and synonyms). e authors scrutinized the retrieved potential articles for eligibility. For the purposes of this review, powered toothbrushes are defined as all toothbrushes that are driven by an external power source. Due to the broad spectrum of this review, the authors gave preference to clinical trials. However, in order to adopt a mechanistic approach, in vitro studies that were considered to shed some light on the theme were also included. It should also be noted that as clinical trials are included in the present review, it is of utmost importance to include information related to adverse events.
is was the case in the present review, which includes possible adverse effects, especially the development of noncarious cervical lesions.

Effect of Powered Toothbrushes on Dental Biofilm/Microbial Parameters.
One of the main objectives of toothbrushing is to control dental plaque buildup and, consequently, gingival inflammation. In this respect, systematic reviews with meta-analyses are highlighted to investigate the effects of manual versus powered toothbrushes on dental plaque and gingival inflammatory signs. In the study by Jager et al. [7], the results of a meta-analysis of 1,780 subjects indicated that high-frequency, high-amplitude, sonic-powered toothbrushes decreased plaque and gingivitis with significantly better effectiveness than manual toothbrushes.
Different studies have been performed to assess the effect of powered toothbrushes on microbial biofilms, using different laboratory techniques. Several technologies have been incorporated into powered toothbrushes, and a significant effect has been demonstrated for some. Table 1, for example, captures the effect of a sonic technology for powered toothbrushes against oral bacteria. It is important to understand the effects of such toothbrushes in the context of the mechanisms against oral biofilms.

Effect of Powered Toothbrushes on Dental Plaque and Associated Gingival Inflammatory Parameters in Adults.
e use of powered toothbrushes has mainly been studied in adult individuals. To obtain high-quality evidence, randomized controlled clinical trials have been performed. A systematic search of the literature, including keywords related to gingivitis, gingival inflammation, and powered/ powered toothbrushes, yielded 22 studies that met eligibility criteria for inclusion in this review ( Table 2). From these studies, the industry has financed a significant part; however, approximately half of them are independent studies, as indicated in the conflict of interests in the publications.
A synthesis of qualitative information from these studies, chosen by presenting the comparison of interest, is presented in Table 2. Of 22 randomized clinical trials comparing different powered to manual toothbrushes, 15 (68%) demonstrated the superiority of powered toothbrushes to reduce gingival inflammation. e majority of these trials also analyzed plaque buildup and a similar tendency was observed, in which powered toothbrushes had a better effect. Only two studies (9%) demonstrated a better effect of the manual toothbrush on signs of gingival inflammation. e remaining 5 studies did not reveal statistically significant differences between powered and manual toothbrushes on gingival inflammatory parameters. When parameters related to dental plaque are observed, the same tendency of better results for powered toothbrushes is demonstrated. It should be noted that some studies have also assessed probing depth (PD), which is considered a sign of gingival inflammation as well. In this sense, since alterations in PD are possible with an increase/decrease in inflammation, this was considered in the present review.
It needs to be stressed that the present review aims to provide a general overview of the different effects of powered toothbrushes as compared to manual ones. erefore, the inclusion of different types of brushes with different designs, several methods of analysis of both plaque and gingival inflammation, and observation periods prevent the pooling of results for meta-analysis. Summarizing the results, it could be stated that powered toothbrushes consistently provide better plaque removal and a reduction of associated gingival inflammation as compared to manual toothbrushes in studies performed on healthy adult individuals.   International Journal of Dentistry 5    International Journal of Dentistry was observed between the two groups. No significant differences were found between the two groups with regard to PD.

12
International Journal of Dentistry International Journal of Dentistry 13  14 International Journal of Dentistry International Journal of Dentistry 15

Adverse Effects of Powered versus Manual Toothbrushes:
Possible Relationship between Toothbrush Type and Noncarious Lesions. Toothbrushing has increased worldwide as a result of oral hygiene awareness programs. One of the problems arising from this change in behavior is the occurrence of adverse effects, especially gingival recession and noncarious lesions. Studies assessing the potential impact of powered versus manual toothbrushing on the incidence of gingival recession are lacking. e diagnosis of noncarious lesions is part of routine dental practice. ese multifactorial conditions are usually related to the patient's lifestyle, including the type of toothbrush they use. Few studies have sought to evaluate the relationship between different toothbrush types/brushing habits and the development of gingival recession, tooth abrasion, dentin hypersensitivity, and other noncarious lesions.
Although it is important to study the type of toothbrush used, it is also essential to note that differences in the results obtained with different toothbrushes are also modified by brushing variables, such as timing, frequency, and brushing force. In addition, variations in bristle characteristics, such as filament stiffness and end-rounding, have been assumed to influence factors such as hard and soft tissue abrasion [34].
Even though anecdotal information is available from studies related to toothbrushing and adverse events, the body of evidence is still weak, with the majority of studies not evaluating these parameters. Some systematic reviews suggested that there were insufficient data to support or refute the association between different toothbrushes and noninflammatory gingival recession [35]. Most studies claim that the use of powered toothbrushes implies that less force is applied while brushing. However, very few of these studies have shown a significant difference in the incidence or regression of noncarious lesions such as gingival recession, even with less force applied while brushing. is information is also available from a study that solely used powered toothbrushes. It should be emphasized that a very low number of studies have assessed adverse events related to powered toothbrushes. erefore, the findings from this study are considered warranted. [36].
When the act of toothbrushing is assessed in isolation (excepting cases of abusive use, e.g., excess use of abrasive dentifrice), clinically significant effects on tooth surface loss are seen [37]. Gingival abrasions can be found in clinical trials of both manual and powered toothbrushes [38]. erefore, additional laboratory and clinical trials are needed to better evaluate the role of toothbrush type in the development of noncarious lesions (35). What is already known is that individual use of inappropriate brushing techniques is more closely related to the onset of noncarious lesions than the type of toothbrush itself [38].
Five studies included in the present review assessed this potential role. A summary is given in Table 3.

Effect of Powered Toothbrushes on Dental Plaque in the
Youngster Population. Our search of the available literature (Table 4) yielded 5 studies that comparatively evaluated powered versus manual toothbrushes in youngsters. As a whole, there is moderate-quality evidence that powered toothbrushes provide a greater benefit than or benefit equal to manual toothbrushes for children. Both powered and manual toothbrushes remove plaque with reasonable efficacy in this population. Regarding plaque control, 2 of the 5 included studies demonstrated the superiority of powered toothbrushes over manual ones in reducing plaque in children. Of the remaining 3 studies, all described powered and manual toothbrushes as equivalent in this respect. However, within the analyses of individual studies, powered toothbrushes generally tended to perform better. However, the clinical significance of these results remains unclear, and additional research is warranted. It is worth mentioning that this result refers to data collected from various types and brands of powered toothbrushes, including toothbrushes with oscillating, rotating, sonic, and ionic actions; that the age of the patients ranged between 6 to 25 years; and that brushing techniques and brushing time varied.

Effect of Powered Toothbrushes on Dental Plaque in Special-Needs Populations.
Optimal levels of plaque control are of utmost importance at all ages to achieve adequate levels of oral health. However, mechanical strategies for plaque control often fail to achieve the desired or optimal levels. is is especially true for individuals that lack motor skills or that have special needs. For these reasons, powered toothbrushes have a definite indication for patients lacking fine motor skills, such as those with certain disabilities and autism [47]. e adequacy of plaque control depends on patient adherence. In physically or mentally disabled individuals, difficulties in oral hygiene maintenance are common enough that oral hygiene practices may need to be simplified or modified to suit the individual situation [48].
In the present review, it is inferred that there is moderate-quality evidence that powered toothbrushes provide a greater or equal benefit than manual brushes in specialneeds patients. Indeed, both manual and powered toothbrushes decrease levels of plaque and gingival inflammation in this population. Among the 7 clinical trials comparing the effects of powered and manual toothbrushes on plaque control in special-needs individuals, which were included in this review (Table 5), 3 studies demonstrated a superiority of powered over manual toothbrushes in reducing plaque and gingival inflammation. In the remaining 4 studies, an equivalence between powered and manual toothbrushes (or individualized manuals) was observed. It is noteworthy that this result refers to data collected from various types of powered toothbrushes, including toothbrushes with oscillating, rotating, sonic, and ionic actions, and that the age of the patients ranged widely (6 to 34.5 years), as did brushing techniques and times. It must however be taken into account that the type and level of disability of the participants of the included studies also varied. In this sense, each work should be carefully read and understood, with the clinical perspective of to whom these results should apply.

22
International Journal of Dentistry Behavioral assessment was carried out using the Frankl Behavior Scale 7-day period with each type with 7day washout period in between. e use of powered or manual toothbrush had no effect on the quantity of dental biofilm removed in children and teenagers with DS, nor did it influence their cooperation during the procedure.
International Journal of Dentistry 23  International Journal of Dentistry 25

28
International Journal of Dentistry Bleeding Index All subjects in both treatment groups, but not the control group, were also instructed to use a 0.05% NaF mint-flavored mouth rinse (Flurigard, Colgate) once a day at bedtime. ey were told to keep half ounce of the rinse in their mouth for 1 minute and then to expectorate, but not rinse with water, after using the rinse. ese instructions also were reinforced at each monthly visit.
e results showed that although there were no significant differences between the three groups at baseline, the Rota-dent group showed significantly (p < 0.05) less posttreatment decalcification than either the control or rinse groups. In a separate analysis of first molars, the Rota-dent group again showed the least decalcification and the control group showed the most. is result should be interpreted in light of the concept of personalized oral care, in which each individual needs to be evaluated and monitored over time in order to understand the clinical benefit of each preventive or therapeutic measure.

Effect of Powered Toothbrushes on Dental Plaque/Gingival Inflammatory Signs or Demineralization in Orthodontic
Patients. Fixed orthodontic appliances unquestionably increase the difficulty of self-performed mechanical plaque control. In this sense, all attempts to enhance the quality of oral hygiene should be pursued, including the use of powered toothbrushes.
is review included 8 studies assessing this population (Table 6).
e vast majority of studies (all but one) evaluated the effect on plaque control and/or gingival inflammatory signs. e remaining studies [54] focused on dental caries and demineralization of enamel surfaces. Half of the studies (including the one focusing on demineralization) demonstrated the superiority of powered toothbrushes compared to manual toothbrushes.
ree studies demonstrated the equivalence of the effect of powered and manual toothbrushes [58][59][60], and one study [55] showed a better effect of manual toothbrushes.
Similar to the other topics of the present review, even though there is no consensus, there is a trend toward better effects with powered toothbrushes. ese results should always be interpreted with caution in terms of effect size. In this topic, motivation has also been studied, and it has been suggested that powered toothbrushes present an interesting result in this respect, suggesting superiority. In summary, there is a role for powered toothbrushes for individuals under fixed orthodontic therapy.

Concluding Remarks
e present narrative review of the literature sought to increase awareness among dental care practitioners about the effects of powered toothbrushes as compared to manual ones. It is well known that oral hygiene methods should be individualized, and, therefore, each individual should be advised by his or her dentist or dental hygienist about which would be more suitable.
e results found in this review are generally consistent with the superiority of powered toothbrushes as compared to manual ones, especially concerning dental plaque removal and associated reduction of gingival inflammation. Table 7 summarizes the evidence included in the present review in the different areas of interest assessed. e studies included in this review observed the effects of powered toothbrushes on adults, children, individuals with special needs, and orthodontic patients. In general, the effect of powered toothbrushes was significantly superior to that of manual toothbrushes, with no evidence of a higher incidence of adverse effects. e vast majority of included studies did not look for patient-centered outcomes, motivation, satisfaction, etc. In this sense, additional studies are warranted. e findings of this narrative review suggest that the powered toothbrush is a very promising alternative for self-performed plaque control.
Data Availability e data are available on Pubmed. Disclosure e present review was performed with the support of Colgate Palmolive.

Conflicts of Interest
e authors declare no conflicts of interest.