Brushing without brushing?—a review of the efficacy of powered toothbrushes in noncontact biofilm removal

Critical hydrodynamic force levels for efficient removal of oral biofilms in simulated interdental spaces

OBJECTIVES

Sonic toothbrushes generate hydrodynamic shear forces for oral biofilm removal on tooth surfaces, but the effective thresholds for biofilm removal remain unexplored. This in vitro study aimed to investigate various threshold values for hydrodynamic biofilm removal in vitro.

MATERIALS AND METHODS

A specialized test bench was designed with a known water flow field within a gap, ensuring that hydrodynamic shear forces on the wall were solely dependent on the volume flow, which was quantifiable using an integrated flow meter and proven by a computational fluid dynamics simulation. A young 20 h supragingival six-species biofilm was developed on hydroxyapatite disks (∅ 5 mm) and applied into the test bench, subjecting them to ascending force levels ranging from 0 to 135 Pa. The remaining biofilms were quantified using colony forming units (CFU) and subjected to statistical analysis through one-way ANOVA.

RESULTS

Volume flow measures < 0.1 l/s: Error 1% of reading were established with the test bench. Untreated biofilms (0 Pa, no hydrodynamic shear forces) reached 7.7E7 CFU/harvest and differed significantly from all treated biofilm groups. CFU reductions of up to 2.3E6 were detected using 20 Pa, and reductions of two orders of magnitude were reached above wall shear forces of 45 Pa (6.9E5).

CONCLUSIONS

Critical hydrodynamic force levels of at least 20 Pa appear to be necessary to have a discernible impact on initial biofilm removal.

CLINICAL RELEVANCE

Pure hydrodynamic forces alone are insufficient for adequate biofilm removal. The addition of antiseptics is essential to penetrate and disrupt hydrodynamically loosened biofilm structures effectively.

Investigation of the effects of Bipolar Radiofrequency Energy on the Structural Morphology of Dental Plaque

OBJECTIVES

 To investigate the effects of radiofrequency (RF) energy, applied through a power toothbrush, on the structural morphology of dental plaque and its bacteria components. Previous studies showed that a toothbrush powered by RF (ToothWave) effectively reduces extrinsic tooth stains, plaque, and calculus. However, the mechanism by which it reduces dental plaque deposits is not fully established.

MATERIALS AND METHODS

 Multispecies plaques at sampling time points of 24, 48, and 72 hours were treated with the application of RF using ToothWave with the toothbrush bristles 1 mm above the plaque surface. Groups that underwent the same protocol but without RF treatment served as paired controls. Confocal laser scanning microscope (CLSM) was used to determine cell viability at each time point. Plaque morphology and bacteria ultrastructure were viewed using scanning electron microscope (SEM) and transmission electron microscope (TEM), respectively.

STATISTICAL ANALYSIS

 Data were analyzed statistically using analysis of variance (ANOVA) and Bonferroni post-tests.

RESULTS

 At each time, RF treatment significantly (p < 0.05) reduced the viable cells in plaque and caused a substantial disruption of plaque morphology, while the untreated plaque had intact morphology. Cells in treated plaques showed disrupted cell walls, cytoplasmic material, huge vacuoles, and heterogeneity in electron density, while these organelles remained intact in untreated plaques.

CONCLUSION

 The application of RF via a power toothbrush can disrupt plaque morphology and kill bacteria. These effects were enhanced by the combined application of RF and toothpaste.

Rational Designs of Biomaterials for Combating Oral Biofilm Infections

Oral biofilms, which are also known as dental plaque, are the culprit of a wide range of oral diseases and systemic diseases, thus contributing to serious health risks. The manner of how to achieve good control of oral biofilms has been an increasing public concern. Novel antimicrobial biomaterials with highly controllable fabrication and functionalization have been proven to be promising candidates. However, previous reviews have generally emphasized the physicochemical properties, action mode, and application effectiveness of those biomaterials, whereas insufficient attention has been given to the design rationales tailored to different infection types and application scenarios. To offer guidance for better diversification and functionalization of anti-oral-biofilm biomaterials, this review details the up-to-date design rationales in three aspects: the core strategies in combating oral biofilm, as well as the biomaterials with advanced antibiofilm capacity and multiple functions based on the improvement or combination of the abovementioned antimicrobial strategies. Thereafter, insights on the existing challenges and future improvement of biomaterial-assisted oral biofilm treatments are proposed, hoping to provide a theoretical basis and reference for the subsequent design and application of antibiofilm biomaterials.

Effect of a multichannel oral irrigator on periodontal health and the oral microbiome

Oral biofilms or dental plaques are one of the major etiological factors for diverse oral diseases. We aimed to evaluate the effect of a multichannel oral irrigator (MCOI) on periodontal health in 29 participants randomly divided into two groups: the MCOI group and the control group. To evaluate the effect of the MCOI on periodontal health, the modified Quigley Hein Plaque Index (PI), Mühlemann-Son Sulcus Bleeding Index (SBI), bleeding on probing (BOP), and swelling were evaluated and compared before and after MCOI use for 3 days. Although PI and SBI showed statistically significant increases in the control group, the MCOI group showed no significant changes in either parameter. Moreover, the percentage of BOP was significantly lower in the MCOI group. Saliva samples were analyzed by 16s rRNA amplicon sequencing to investigate changes in the oral microbiome. Sequencing results showed that Porphyromonas spp. were significantly increased in the control group, whereas no significant change was detected in the MCOI group. Using the MCOI, enriched populations and functional pathways were detected in pioneer species comprising non-mutans streptococci. These findings provide evidence of the effectiveness of the MCOI in maintaining periodontal health and a healthy microbial ecology in the oral cavity.

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.

Strategies to Combat Caries by Maintaining the Integrity of Biofilm and Homeostasis during the Rapid Phase of Supragingival Plaque Formation

Bacteria in the oral cavity, including commensals and opportunistic pathogens, are organized into highly specialized sessile communities, coexisting in homeostasis with the host under healthy conditions. A dysbiotic environment during biofilm evolution, however, allows opportunistic pathogens to become the dominant species at caries-affected sites at the expense of health-associated taxa. Combining tooth brushing with dentifrices or rinses combat the onset of caries by partially removes plaque, but resulting in the biofilm remaining in an immature state with undesirables’ consequences on homeostasis and oral ecosystem. This leads to the need for therapeutic pathways that focus on preserving balance in the oral microbiota and applying strategies to combat caries by maintaining biofilm integrity and homeostasis during the rapid phase of supragingival plaque formation. Adhesion, nutrition, and communication are fundamental in this phase in which the bacteria that have survived these adverse conditions rebuild and reorganize the biofilm, and are considered targets for designing preventive strategies to guide the biofilm towards a composition compatible with health. The present review summarizes the most important advances and future prospects for therapies based on the maintenance of biofilm integrity and homeostasis as a preventive measure of dysbiosis focused on these three key factors during the rapid phase of plaque formation.

Comparative Study of Different Sampling Methods of Biofilm Formed on Stainless-Steel Surfaces in a CDC Biofilm Reactor

The formation of biofilms in dairy processing plants can reduce equipment efficiency, contribute to surface deterioration, and contaminate dairy products by releasing the microorganisms they contain, which may cause spoilage or disease. However, a more representative identification of microbial communities and physico-chemical characterization requires to detach and recover adequately the entire biofilm from the surface. The aim of this study is to develop an efficient technique for in-plant biofilm sampling by growing a strain of Pseudomonas azotoformans PFl1A on stainless-steel surface in a dynamic CDC biofilm reactor system using tryptic soy broth (TSB) and milk as growth media. Different techniques, namely, swabbing, scraping, sonic brushing, synthetic sponge, and sonicating synthetic sponge were used and the results were compared to a standard ASTM International method using ultrasonication. Their efficiencies were evaluated by cells enumeration and scanning electron microscopy. The maximum total viable counts of 8.65 ± 0.06, 8.75 ± 0.08, and 8.71 ± 0.09 log CFU/cm2 were obtained in TSB medium using scraping, synthetic sponge, and sonicating synthetic sponge, respectively, which showed no statistically significant differences with the standard method, ultrasonication (8.74 ± 0.02 log CFU/cm2). However, a significantly (p &lt; 0.05) lower cell recovery of 8.57 ± 0.10 and 8.60 ± 0.00 log CFU/cm2 compared to ultrasonication were achieved for swabbing and sonic brushing, respectively. Furthermore, scanning electron microscopy showed an effective removal of biofilms by sonic brushing, synthetic sponge, and sonicating synthetic sponge; However, only the latter two methods guaranteed a superior release of bacterial biofilm into suspension. Nevertheless, a combination of sonication and synthetic sponge ensured dislodging of sessile cells from surface crevices. The results suggest that a sonicating synthetic sponge could be a promising method for biofilm recovery in processing plants, which can be practically used in the dairy industries as an alternative to ultrasonication.

Effects of Electric-Toothbrush Vibrations on the Expression of Collagen and Non-Collagen Proteins through the Focal Adhesion Kinase Signaling Pathway in Gingival Fibroblasts

Electric-toothbrush vibrations, which remove plaque, are transmitted to the gingival connective tissue via epithelial cells. Physical energy affects cell function; however, the effects of electric-toothbrush vibrations on gingival extracellular matrix (ECM) protein expression remain unknown. We aimed to examine the effects of these vibrations on the expression of ECM proteins—type I collagen (col I), type III collagen (col III), elastin, and fibronectin (FN)—using human gingival fibroblasts (HGnFs). HGnFs were seeded for 5 days in a six-well plate with a hydrophilic surface, exposed to electric-toothbrush vibrations, and cultured for 7 days. Subsequently, the mRNA and protein levels of col I, col III, elastin, and FN were examined. To investigate the role of focal adhesion kinase (FAK) signaling on ECM protein expression in vibration-stimulated cells, the cells were treated with siRNA against protein tyrosine kinase (PTK). Electric-toothbrush vibrations increased col I, col III, elastin, and FN expression; promoted collagen and non-collagen protein production; and enhanced FAK phosphorylation in HGnFs. Moreover, PTK2 siRNA completely blocked the effects of these vibrations on the expression of col I, col III and elastin mRNA. The results suggest that electric-toothbrush vibrations increase collagen, elastin, and FN production through the FAK-signaling pathway in fibroblasts.

Interdental biofilm reduction and composition after use of an activated and inactivated side-to-side toothbrush - a proof-of-principle clinical study

OBJECTIVES

To evaluate interdental biofilm reduction and composition after powered toothbrushing with a side-to-side (sonic) toothbrush compared to manual toothbrushing following single brushing exercises in periodontally healthy young adults.

MATERIALS AND METHODS

All participants brushed with a side-to-side toothbrush without toothpaste in four different modes: toothbrush (a) inactivated without instruction (OFF-NI), (b) activated without instruction (ON-NI), (c) inactivated with instruction (OFF-I), and (d) activated with instruction (ON-I) at consecutive visits (single brushing exercises). Before and after brushing, the Approximal Plaque Index (API) was assessed at three interdental spaces and plaque samples were taken from two interdental sites. Biofilm reduction and composition were analyzed microbiologically by total bacterial load and 16S rRNA sequencing.

RESULTS

Thirty participants (age: 22.9 ± 2.5 years) completed the study. Most participants showed no or incomplete plaque removal assessed by API following single brushing exercises, while the frequency of API reduction was higher after ON-NI compared to OFF-I (p = 0.023). Irrespective of the brushing mode, a significant reduction of total bacterial load was detected with lower bacterial counts after OFF-NI compared to ON-NI (p = 0.008) and ON-I (p = 0.007). Biofilm composition showed slight changes in the relative abundances of bacterial taxa, regardless of the brushing mode.

CONCLUSIONS

Manual and powered toothbrushing with a side-to-side toothbrush, with and without instruction, showed incomplete interdental biofilm removal in periodontally healthy young adults following single brushing exercises.

CLINICAL RELEVANCE

Data has to be validated in further studies on other groups, however, in periodontally healthy young adults, additional devices seem to be necessary for sufficient interdental cleaning.

Efficacy of a sonic toothbrush on plaque removal-A video-controlled explorative clinical trial

Clinical studies on the efficacy of sonic toothbrushes show inconsistent results, most studies have been conducted without sufficient supervision of appropriate toothbrush usage. Aims of the explorative clinical trial were therefore to investigate whether the usage of an activated sonic toothbrush reduces plaque more effectively than an inactivated one used as a manual toothbrush, and to which extent the correct use of such toothbrush plays a role in its efficacy. The clinical trial was designed as a video-controlled interventional study. Thirty participants (mean (±SD) age 22.9 (±2.5) years) were included, areas of interest were the buccal surfaces of the upper premolars and the first molar (partial mouth recording). Toothbrushing was performed without toothpaste in a single brushing exercise under four different conditions: switched off, habitually used as manual toothbrush, no instruction; switched on, habitually used as powered toothbrush, no instruction; switched off, used as manual toothbrush, instruction in the Modified Bass Technique; switched on, used as powered toothbrush, instruction in a specific technique for sonic toothbrushes. Brushing performance was controlled by videotaping, plaque was assessed at baseline (after 4 days without toothbrushing) using the Rustogi modified Navy-Plaque-Index and planimetry. Main study results were that plaque decreased distinctly after habitual brushing regardless of using the sonic brush in ON or OFF mode (p for all comparisons < 0.001). After instruction, participants were able to use the sonic brush in ON mode as intended, with only minor impact on efficacy. Using the toothbrush in OFF mode with the Modified Bass Technique was significantly less effective than all other conditions (p for all comparisons < 0.001). Under the conditions used, the sonic toothbrush was not more effective when switched on than when switched off, and there was no evidence that the correct use of the toothbrush was more effective than the habitual use.

Improved Oral Health and Adaptation to Treatment in Dogs Using Manual or Ultrasonic Toothbrush or Textile of Nylon or Microfiber for Active Dental Home Care

Poor oral health is a common problem in dogs causing pain and impaired welfare. The gold standard to maintain good oral health and prevent periodontitis is daily tooth brushing. However, many dog owners find it difficult, and dogs often show aversive behavior. There are several different tools available, and in this intra-subject study, four different active dental home care treatment options were examined: manual and ultrasonic toothbrush, a nylon glove, and a microfiber finger cloth. The treatments were evaluated for efficacy against gingivitis, plaque, and calculus in beagle dogs. Each dog received two treatments on the buccal sides of the teeth once daily, either two types of toothbrushes (N = 10) or two types of textiles (N = 11), on separate sides of the mouth. The dogs' teeth were assessed before and after the five-week treatment period, with the assessor blinded by additional, similar dogs (N = 7). The study also assessed the dogs' stress levels during treatment using a fear, anxiety, stress (FAS) protocol. All four treatments improved dog oral health, reducing gingivitis and plaque. Furthermore, the amount of calculus also decreased in some individuals. Adaptation to dental care occurred in the dogs over time. This information can be used to encourage dog owners to brush their dogs' teeth.

A two-week single-group longitudinal test of a new sonic-powered toothbrush simulating the 'bass brushing technique' with tapered bristles on the brush head for reduction of dental plaque and gingivitis

OBJECTIVE

To investigate the effect of a new powered toothbrush with tapered bristles on the brush head for the reduction of dental plaque and gingivitis.

METHODS

This was a single-centre, single-group, longitudinal clinical trial. Thirty-two participants who were typical manual toothbrush users were recruited and assigned the sonic-powered brush. Interviews were arranged on the 1^st , 4^th , and 15^th days which represented the baseline (T₁ ), middle (T₂ ) and final (T₃ ) time points, respectively. At each visit, the plaque index (PlI), gingival index (GI), bleeding on probing (BOP) and probing depth (PD) were recorded for the Ramfjord index teeth, gingival crevicular fluid(GCF) samples were collected and the proportions of eight periodontal pathogenic bacteria were analysed. Repeated-measures analysis of variance (ANOVA) was used for comparisons at different time points.

RESULTS

PlI was significantly reduced by 41.67% from T₁ to T₂ (p<0.001) and decreased by 18.57% from T₂ to T₃ (p=0.003). GI also varied significantly from T₁ to T₂ (p=0.018) and T₁ to T₃ (p=0.037). A 35.86% reduction in the BOP percentage occurred after using the sonic-powered toothbrush for 3 days (p=0.001). However, no significant difference was observed in the mean values of PD at different examination intervals (p=0.529). There was no significant difference in the proportions of bacteria between T₁ and T₃ (p>0.05).

CONCLUSION

This research demonstrated the efficacy of the sonic-powered brush handle together with tapered bristles on the brush in reducing plaque and gingivitis within a short time period.

A profilometric and scanning electron microscopic analysis of tooth surface abrasion caused by rotary/oscillatory, linear motion, sonic, and ultrasonic toothbrushes: An in vitro study

Background:

Adequate plaque control facilitates good gingival and periodontal health, prevents tooth decay, and preserves oral health. Toothbrushing is the primary method of removing plaque and can be classified into powered and manual toothbrushes.

Aim:

The primary objective was to compare the abrasiveness and surface roughness caused by four different power-driven toothbrushes with a different mode of action, on tooth surfaces in vitro.

Materials and Methods:

An in vitro experiment was conducted on eighty freshly extracted tooth specimens which were equally divided into four groups. Each group was brushed with the specifically assigned electric toothbrush to that group, but keeping parameters such as force applied during brushing, storage of tooth before and after brushing, and toothbrushing time same. A total of the 2-month study was done on each tooth specimen. Tooth surface roughness was recorded before and after the toothbrushing experiment to check the difference between surface roughness readings. Scanning electron microscopic (SEM) analysis was done afterward to analyse the surface topography of each group specimens.

Statistical Analysis Used:

Paired t-test used for intergroup analysis and intragroup analysis was done using Kruskal–Wallis test.

Results:

After comparing the baseline and final readings of each group, it has been found that the mean difference between values is highly significant in Group 1 (rotary/oscillatory). The mean rank of Group 1 was least in all four groups, which showed the highest tooth surface abrasion in that group. SEM analysis also revealed that Group 1 tooth specimens had deeper scratches/lines comparatively to other groups.

Conclusion:

Rotary/oscillatory toothbrush caused the highest tooth surface abrasion when compared with other electronic toothbrushes.

Efficacy of a Hybrid Toothbrush versus Comparative Manual Toothbrush for Plaque Removal - Randomized In-Use Study

Purpose

An innovative hybrid toothbrush was designed to function either in manual sonic mode or combined mode (manual and sonic). The primary objective was to assess the efficacy of a new hybrid powered toothbrush (PTB) used in combined mode versus a comparative manual toothbrush (MTB) for plaque removal, after 14 days of twice-daily use under normal conditions. The secondary objectives were to evaluate the gingival state, to evaluate the tolerance of the hybrid PTB and to evaluate its acceptability.

Materials and Methods

This study was a monocentric, block-randomized, dual treatment, parallel group, and examiner-blinded trial with before and after evaluation. It was conducted on two groups of 55 subjects presenting a visible plaque accumulation (score ≥2 as measured by the Turesky Modification of the Quigley-Hein Plaque Index (TMQHPI)). On Day 1/Day 8/Day 15, the same investigator conducted blind clinical examinations on each subject and evaluated TMQHPI and Papillary Bleeding Score (PBS). On Day 1, the subjects received either the hybrid PTB or the comparative MTB and used it twice daily under normal conditions of use.

Results

The hybrid PTB used in its combined mode eliminates dental plaque more efficiently than the comparative MTB, especially in difficult-to-access areas such as posterior and interproximal dental surfaces, while remaining gentle on the gingivae. The PBS was significantly lower with the hybrid toothbrush compared with the reference manual one.

Conclusion

The new device confirmed previous findings and should improve oral hygiene following the manufacturer's instructions. Moreover, the specific design of the toothbrush means that it can be used according to the oral environment conditions and personal feeling.

Impact of interdental brush shape on interpapillary cleaning efficacy - a clinical trial

This study aimed to investigate whether interdental brush shape influences cleaning efficacy, by comparing a waist-shaped interdental brush (W-IDB) with a cylindrical IDB (C-IDB); both provided with the same bristle texture. Cleaning efficacy of differently shaped IDBs was measured in proximal surfaces of teeth in a split-mouth cross-over design. Twenty-eight patients abolished oral hygiene for 4 d. Line angle plaque area was scanned with an intraoral camera after use of disclosing dye in baseline and after IDB application and analyzed planimetrically. Additionally, bacterial load in the IDBs was analyzed after usage by colony forming units (cfu). A Wilcoxon signed-rank test with continuity correction was used to compare the results of the waist-shaped and the cylindrically-shaped IDBs. The waist-shaped IDBs cleaned significantly better than their cylindrically-shaped counterparts (area cleaned: 23.1% vs. 18.3%), when applied at same interdental spaces (p < 0.001). However, no significant differences were found in comparison of bacterial load on the IDBs (median cfu counts: 2.3E9 vs. 2.7E9, p = 0.93). Irrespective of bristle texture or size, IDB shape have impact on cleaning efficacy. Waist-shaped IDBs are more effective in cleaning of the line angle area than cylindrically-shaped IDBs.

Dental Plaque Removal by Ultrasonic Toothbrushes

With the variety of toothbrushes on the market, the question arises, which toothbrush is best suited to maintain oral health? This thematic review focuses first on plaque formation mechanisms and then on the plaque removal effectiveness of ultrasonic toothbrushes and their potential in preventing oral diseases like periodontitis, gingivitis, and caries. We overviewed the physical effects that occurred during brushing and tried to address the question of whether ultrasonic toothbrushes effectively reduced the microbial burden by increasing the hydrodynamic forces. The results of published studies show that electric toothbrushes, which combine ultrasonic and sonic (or acoustic and mechanic) actions, may have the most promising effect on good oral health. Existing ultrasonic/sonic toothbrush models do not significantly differ regarding the removal of dental biofilm and the reduction of gingival inflammation compared with other electrically powered toothbrushes, whereas the manual toothbrushes show a lower effectiveness.

Nanoparticles for the Treatment of Oral Biofilms: Current State, Mechanisms, Influencing Factors, and Prospects

Due to their excellent size, designability, and outstanding targeted antibacterial effects, nanoparticles have become a potential option for controlling oral biofilm-related infections. However, the formation of an oral biofilm is a dynamic process, and factors affecting the performance of antibiofilm treatments are complex. As such, when examining the existing literature on the antibiofilm effects of nanoparticles, attention should be paid to the specific mechanisms of action at different stages of oral biofilm formation, as well as relevant influencing factors, in order to achieve an objective and comprehensive evaluation. This review is intended to detail the antibacterial mechanisms of nanoparticles during the four stages of the formation of oral biofilms: 1) acquired film formation; 2) bacterial adhesion; 3) early biofilm development; and 4) biofilm maturation. In addition, factors influencing the antibiofilm properties of nanoparticles are summarized from the aspects of nanoparticles themselves, biofilm models, and host factors. The limitations of current research and possible trends for future research are also discussed. In summary, nanoparticles are a promising antioral biofilm strategy. It is hoped that this review can serve as a reference and inspire ideas for further research on the application of nanoparticles for effectively targeting and treating oral biofilms.

Long-term impact of powered toothbrush on oral health: 11-year cohort study

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 examinations were included. Mixed‐effects linear regression models were constructed between 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 potential 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)] and mean CAL [β: −0.19 (95% CI: −0.32; −0.07)] progressions; and had 17.7% less DMFS progression and 19.5% more teeth retained than the manual toothbrushers.

Conclusions

In the long‐term, powered toothbrush seems to be effective in reducing mean PD and mean CAL progressions, besides increasing the number of teeth retained.

A new tooth brushing approach supported by an innovative hybrid toothbrush-compared reduction of dental plaque after a single use versus an oscillating-rotating powered toothbrush

Background

An innovative hybrid toothbrush was designed functioning either in manual mode, in powered mode (sonic) or in combined mode (manual and powered). The primary aim of this study was to evaluate and compare the clinical efficacy of this first hybrid toothbrush (Elgydium Clinic/Inava Hybrid) used in combined mode to a marketed oscillating-rotating powered toothbrush (Oral-B Vitality) in the reduction of dental plaque after a single use. The secondary aims were to evaluate the tolerance and acceptability of each device.

Methods

It was a randomized, examiner-blind, single-center study performed on two parallel groups: hybrid toothbrush (n = 33) versus oscillating-rotating toothbrush (n = 33). A brushing exercise was conducted for two minutes on subjects presenting a “Silness and Löe Plaque Index” (PI) between 1.0 and 2.0 and a “Modified Gingival Index” between 1.0 and 2.0. They were not to have ever used an electric toothbrush. To assess the device effect after brushing, a paired t-test was applied on the change outcome (After-Before brushing). An unpaired t-test was used to compare the efficacy of both devices. A global tolerance assessment of each powered toothbrush was done on all the subjects. The number and percentage of reactions related to each toothbrush was collected and the final tolerance assessment was estimated.

Results

After a single use, the hybrid toothbrush used in combined mode presented a global anti-plaque efficacy characterized by a significant decrease of the global PI of 45% on average (p < 0.0001; paired t-test). It was as effective as the oscillating rotating toothbrush in plaque removal (p > 0.05; unpaired t-test). The global tolerance of both toothbrushes was judged as “Good” and they were equally appreciated by the users.

Conclusion

The results of this one-time use trial demonstrate the efficacy of the hybrid toothbrush used in combined mode for plaque removal. The hybrid toothbrush design allows each user to adapt tooth brushing to his preference (manual / sonic / combined), his skills or his mouth condition. We hypothesize that such an individualized approach can favor long term compliance with oral health recommendations and improve global oral wellness.

Trial Registration

ISRCTN12394494, 20/02/2018 - Retrospectively registered.

Influence of the amplitude of different side-to-side toothbrushes on noncontact biofilm removal

OBJECTIVES

To investigate the impact of the lateral deflection of toothbrush bristles (amplitude) of three side-to-side toothbrushes for noncontact biofilm removal in an artificial interdental space model.

MATERIALS AND METHODS

A three-species biofilm (Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus sanguinis) was formed in vitro on protein-coated titanium disks. A flow chamber system was combined with a static biofilm growth model. The amplitudes of three commercial side-to-side toothbrushes were evaluated by means of a dose response analysis. The amplitudes were decreased in steps (100%, 85%, 70%, 55%, and 40%). Subsequently, the biofilm-coated substrates were exposed to the toothbrushes. The biofilms were analyzed with confocal laser scanning microscope images and measured using volumetric analyses.

RESULTS

The predictability of interdental biofilm reduction differed among the toothbrushes. A lower variety in the results of repeated experiments occurred in toothbrush C compared to toothbrushes A and B. Toothbrush C obtained highest percentage of biofilm reduction by 85% of amplitude power setting (median biofilm reduction 76%). Decreasing the amplitude from 85 to 40% resulted in reduced biofilm reduction (p = 0.029). In contrast, no significance could be observed for the differences of the tested amplitudes within toothbrushes A and B (p > 0.05). Between the toothbrushes, a significant difference in interdental biofilm reduction was found between C-A (p = 0.029) and C-B (p = 0.029) with amplitude of 85%.

CONCLUSIONS

The amplitude of one of the investigated side-to-side toothbrushes affected the biofilm reduction predictably in an interdental space model.

CLINICAL RELEVANCE

Within certain toothbrushes, a specific amplitude power setting may demonstrate beneficial effects on noncontact biofilm removal.

Surface roughness and bacterial adhesion on root dentin treated with diode laser and conventional desensitizing agents

The treatments for dentin hypersensitivity (DH) may change the surface roughness of the root dentin, which can lead to biofilm accumulation, increasing the risk of root caries. The aim was to compare the surface roughness of root dentin after different treatments of DH and the biofilm formation on those surfaces. After initial surface roughness (Sa) assessment, 50 bovine root fragments received the following treatments (n = 10): G 1-no treatment; G2-5% sodium fluoride varnish; G3-professional application of a desensitizing dentifrice; G4-toothbrushing with a desensitizing dentifrice; and G5-diode laser application (908 nm; 1.5 W, 20 s). The Sa was reevaluated after treatments. Afterward, all samples were incubated in a suspension of Streptococcus mutans at 37 °C for 24 h. The colony-forming units (CFU) were counted using a stereoscope, and the results were expressed in CFU/mL. The one-way ANOVA and the Tukey's tests compared the roughness data and the results obtained on the bacterial adhesion test (α = 5%). G2 (2.3 ± 1.67%) showed similar Sa variation than G1 (0.25 ± 0.41%) and G5 (5.69 ± 0.99%), but different from group G3 (9.05 ± 2.39%). Group 4 showed the highest Sa variation (30.02 ± 3.83%; p < 0.05). Bacterial adhesion was higher in G4 (2208 ± 211.9), suggesting that bacterial growth is greater on rougher surfaces. The diode laser and the conventional treatments for DH may change the surface roughness of the root dentin, but only brushing with desensitizing dentifrice induced a higher bacteria accumulation on root dentin surface.

Efficacy of various side-to-side toothbrushes and impact of brushing parameters on noncontact biofilm removal in an interdental space model

OBJECTIVES

The objective of this study was to evaluate the efficacy of four different side-to-side toothbrushes and the impact of various brushing parameters on noncontact biofilm removal in an adjustable interdental space model.

MATERIALS AND METHODS

A three-species biofilm, consisting of Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus sanguinis, was formed in vitro on protein-coated titanium disks using a flow chamber combined with a static biofilm growth model. Subsequently, the biofilm-coated disks were exposed to four different powered toothbrushes (A, B, C, D). The parameters distance (0 and 1 mm), brushing time (2, 4, and 6 s), interdental space width (1, 2, and 3 mm), and toothbrush angulation (45° and 90°) were tested. The biofilm volumes were determined using volumetric analyses with confocal laser scanning microscope (Zeiss LSM700) images and Imaris version 7.7.2 software.

RESULTS

The median percentages of simulated interdental biofilm reduction by the tested toothbrushes ranged from 7 to 64 %. The abilities of the analyzed toothbrushes to reduce the in vitro biofilm differed significantly (p < 0.05). Three of the tested toothbrushes (A, B, C) were able to significantly reduce a simulated interdental biofilm by noncontact brushing (p ≤ 0.005). The brushing parameters and their combinations tested in the experiments revealed only minor effects on in vitro interdental biofilm reduction (p > 0.05).

CONCLUSIONS

A three-species in vitro biofilm could be altered by noncontact brushing with toothbrushes A, B, and C in an artificial interdental space model.

CLINICAL RELEVANCE

Certain side-to-side toothbrushes demonstrate in vitro a high efficacy in interdental biofilm removal without bristle-to-biofilm contact.

Antimicrobials Influence Bond Stiffness and Detachment of Oral Bacteria

Oral biofilm can never be fully removed by oral hygiene measures. Biofilm left behind after brushing is often left behind on the same sites and exposed multiple times to antimicrobials from toothpastes and mouthrinses, after which removal becomes increasingly difficult. On the basis of this observation, we hypothesize that oral bacteria adhering to salivary conditioning films become more difficult to remove after adsorption of antimicrobials due to stiffening of their adhesive bond. To verify this hypothesis, bacteria adhering to bare and saliva-coated glass were exposed to 3 different mouthrinses, containing chlorhexidine-digluconate, cetylpyridinium-chloride, or amine-fluoride, after which bacterial vibration spectroscopy was carried out or a liquid-air interface was passed over the adhering bacteria to stimulate their detachment. Brownian motion–induced nanoscopic vibration amplitudes of 4 oral streptococcal strains, reflecting their bond stiffness, decreased after exposure to mouthrinses. Concurrently, the percentage detachment of adhering bacteria upon the passage of a liquid-air interface decreased after exposure to mouthrinses. A buffer control left both vibration amplitudes and detachment percentages unaffected. Exposure to either of the selected mouthrinses yielded more positively charged bacteria by particulate microelectrophoresis, suggesting antimicrobial adsorption to bacterial cell surface components. To rule out that exposure of adhering bacteria to the mouthrinses stimulated polysaccharide production with an impact on their detachment, Fourier transform infrared spectroscopy was carried out on bacteria adhering to an internal reflection element, prior to and after exposure to the mouthrinses. Infrared absorption band areas indicated no significant change in amount of polysaccharides after exposure of adhering bacteria to mouthrinses, but wave number shifts demonstrated stiffening of polysaccharides in the bond, as a result of antimicrobial adsorption to the bacterial cell surface and in line with changes in surface charge. Clinically, these findings suggest that accumulation of oral biofilm exposed to antimicrobials should be prevented (interdental cleaning aids, floss use), as removal becomes progressively more difficult upon multiple exposures.

Interproximal biofilm removal by intervallic use of a sonic toothbrush compared to an oral irrigation system

BACKGROUND

The purpose of this in-vitro study was to investigate the potential of biofilm removal in interproximal tooth regions using intervallic cleaning with an oral irrigator or a sonic toothbrush.

METHODS

Three-species biofilms (Streptococcus mutans (OMZ 918), Streptococcus oralis SK 248 (OMZ 60), Actinomyces naeslundii (OMZ 745)) were grown on hydroxyapatite discs for 3 days in culture media. Every 24 h, specimens were incubated for 15 min in resazurin solution (i.e., culture medium and 10 % v/v alamarBlue®) to measure the metabolic activity with a fluorescence spectrophotometer in relative fluorescence units (rfu) at baseline. Then, specimens were fixed in interproximal holding devices and underwent treatment with an oral irrigator (WF; Waterpik® Sensonic WP-100E), an active sonic toothbrush (WPa), or an inactive sonic toothbrush (WPi; Waterpik® Sensonic SR-3000E) for 10 s (n = 18/group). Untreated biofilms served as controls (CO). After treatment, bacterial activity was re-measured, and specimens were re-grown in fresh medium for 24 h until next cleaning procedure. Altogether, cleaning was repeated in intervals of three treatment days (d1, d2, d3). After d3, SEM images were taken (n = 8) and CFU was measured (n = 3). Metabolic activity was analyzed for each disc separately, rfu values were averaged for d1 to compare initial biofilm stability, and ratios of baseline and post-treatment values were compared. Results were analyzed using ANOVA with the post-hoc Scheffé test, or Kruskal-Wallis with post-hoc Mann-Whitney test.

RESULTS

Median baseline rfu-values of d1 resulted in 7821.8 rfu (interquartile range = 5114.5). Highest reduction in metabolic activity was recorded significantly for the oral irrigator used for 10 s (residual activity per day d1: WF 17.9 %, WPa 58.8 %, WPi 82.5 %, CO 89.6 %; d2: WF 36.8 %, WPa 85.2 %, WPi 82.5 %, CO 90.0 %; d3: WF 17.2.%, WPa 79.6 %, WPi 96.3 %, CO 116.3 %). SEM images of untreated specimens (CO) and specimens treated with the sonic toothbrush (WPa and WPi) showed huge amounts of biofilm, while oral irrigator-treated specimens (WF) revealed barely any bacteria. CFU data confirmed the graduations between the groups.

CONCLUSIONS

Cleaning of interproximal regions achieved better success with an oral irrigator as compared to the use of a sonic toothbrush. (350/350 words).

Influence of time, toothpaste and saliva in the retention of Streptococcus mutans and Streptococcus sanguinis on different toothbrushes

OBJECTIVES

The intraoral transmission of cariogenic and periodontopathogenic species seems to be facilitated by contaminated toothbrushes and other oral hygiene devices. The aim of this investigation was to analyze the in vitro retention and survival rate of Streptococcus mutans and Streptococcus sanguinis on different toothbrushes. The impacts of human saliva and antimicrobial toothpaste on these parameters were further evaluated.

MATERIAL AND METHODS

Part I: Four toothbrushes (Colgate 360°, Curaprox CS5460 ultra soft, elmex InterX, Trisa Flexible Head3) were contaminated by S. mutans DSM 20523 or S. sanguinis DSM 20068 suspensions for three minutes. Bacteria were removed from the toothbrushes after either three minutes (T0) or 24 hours (T24) of dry storage and grown on Columbia blood agar plates for the quantification of colony-forming units (CFUs). Part II: The effects of saliva from a caries-active or a caries-inactive person and of toothpaste containing 0.12% chlorhexidine digluconate were also tested.

RESULTS

Part I: After three minutes of dry storage, approximately one percent of the bacteria were still detectable on the toothbrushes. After 24 hours, S. sanguinis exhibited a more pronounced decrease in viable cell numbers compared with S. mutans but the differences were not significant (Kruskal-Wallis test, p>0.05). Part II: The addition of human saliva from a caries-active or caries-inactive person slightly increased the retention of both streptococcal species at T0. The use of toothpaste had no influence on the amount of viable streptococci at T0, but it reduced the microbial load after 24 hours of storage. There were only slight nonsignificant differences (p>0.05) between the four toothbrushes.

CONCLUSIONS

In vitro bacterial retention and survival of S. sanguinis and S. mutans on different toothbrushes occurred. Within the limitations of this study, the use of human saliva or an antimicrobial toothpaste did not lead to significant differences in the microbial load on toothbrushes.

Antimicrobial penetration in a dual-species oral biofilm after noncontact brushing: an in vitro study

OBJECTIVES

Oral biofilm is inevitably left behind, even after powered brushing. As a special feature, powered brushing removes biofilm in a noncontact mode. When the brushing distance becomes too large, biofilm is left behind. We hypothesize that biofilm left behind after brushing has different viscoelastic properties than before brushing, impacting antimicrobial penetration.

MATERIALS AND METHODS

In vitro grown dual-species biofilms were subjected to 20 % mechanical deformation before and after powered brushing at 4-mm brushing distance. Biofilm thickness and stress relaxation were measured for unbrushed and brushed biofilms. Stress relaxation was analyzed with a three-element Maxwell model. Antimicrobial penetration from five mouthrinses was microscopically evaluated for unbrushed and brushed biofilms.

RESULTS

Thicknesses of unbrushed and brushed biofilms were similar. Brushing decreased the prevalence of fast and increased the prevalence of slow relaxation elements, which was accompanied by deeper penetration of chlorhexidine and cetylpyridinium chloride. Penetration of antimicrobials from other mouthrinses was relatively low in unbrushed and brushed biofilms.

CONCLUSIONS

This confirmation of our hypothesis points to an additional advantage of powered toothbrushing in a noncontact mode, changing the viscoelastic properties of biofilm in a direction that increases antimicrobial penetration of chlorhexidine and cetylpyridinium.

CLINICAL RELEVANCE

The biofilm left behind after noncontact powered toothbrushing may have less recalcitrance toward penetration of chlorhexidine and cetylpyridinium chloride than prior to brushing.