Evaluation of the use of ultrasound within a power toothbrush to dislodge oral bacteria using an in vitro Streptococcus mutans biofilm model.

PURPOSE: To investigate in vitro the use of ultrasound in a power toothbrush to aid in the removal of dental plaque biofilm without bristle contact. METHODS: Dental plaque was modeled using Streptococcus mutans biofilm adherent to hydroxyapatite disks. Treatment arms included positive and negative controls, disks with and without biofilm, respectively. Power toothbrush modes of action tested included a toothbrush with sonic and ultrasonic action (ULT), the same toothbrush with only sonic action (ULN), a sonic toothbrush (SON) and a rotating/oscillating toothbrush (OSC). The active element of the toothbrushes (bristles or point of ultrasound emission) was immersed in toothpaste slurry and held 3 mm away from the disk surface. Treatment included activation of the toothbrush mode of action for 5 seconds. Control disks were exposed to the same fluid environment but not exposed to a power toothbrush. After treatment, biofilm present on the disks was stained using a red dental plaque disclosing solution. Photographs were then taken and the presence of biofilm assessed using digital image analysis. For each disk a normalized pixel volume, related to the presence of biofilm corrected for lighting, was determined. Statistical testing was done with a one-way ANOVA and a Bonferroni post hoc test. RESULTS: Normalized pixel volumes (mean +/- standard deviation) were 0.428 (0.010) for the negative control and 1.022 (0.040) for the positive control. Normalized pixel volumes for the power toothbrush modes of action were 0.641 (0.075) for ULT, 0.972 (0.027) for ULN, 0.921 (0.010) for SON and 0.955 (0.025) for OSC. Statistical analysis showed a significant treatment effect (P<0.001). All power toothbrush modes of action exhibited some biofilm removal without bristle contact in this in vitro assay. Of the modes of action tested, the combined sonic and ultrasonic mode of action (ULT) removed the greatest amount of biofilm from the disk surfaces. The same toothbrush when tested with (ULT) and without (ULN) ultrasound showed a greater amount of biofilm removed when ultrasound was present.

In vitro safety evaluation of a new ultrasound power toothbrush.

OBJECTIVE: To evaluate the safety of a novel ultrasound power toothbrush using a series of laboratory tests simulating extended brushing on the natural tooth surface, dental restorations, crowns, and orthodontic brackets. METHODS: To evaluate safety on the natural tooth and restored surfaces, human molars (n = 60) were prepared with restorations centered on the facial cementoenamel junction. The specimens received restorations of either 1) amalgam, 2) nanofilled composite resin, 3) glass ionomer, 4) cast gold-cemented with glass ionomer, or 5) pressed ceramic adhesively cemented with a composite resin cement. Orthodontic specimens (n = 33) were created by cementing brackets onto the buccal surfaces of extracted teeth. Crown specimens (n = 32) were created by cementing cast metal crowns onto identical pre-molar metal dies using zinc phosphate. All specimens were exposed to extended brushing in an environment controlled for time, brush head force, and dentifrice slurry. Treatment was assigned randomly to the specimens, and brushing was done with either the ultrasound toothbrush (Ultreo), or one of two positive controls: a manual toothbrush (Oral-B 35) and an oscillating-rotating power toothbrush (Oral-B Triumph). Negative control specimens remained unbrushed. Qualitative analysis via scanning electron microscopy was utilized to evaluate the tooth surface and restoration integrity. Shear and tensile testing was used to evaluate orthodontic bracket and crown retention, respectively. RESULTS: Exposure of the teeth and restored surface to the manual toothbrush resulted in some bristle furrows on cementum/dentin root surfaces, especially at the heights of contour and light grooves on the composite resin surfaces. The two power toothbrushes had no signs of root surface wear. None of the toothbrushes demonstrated breakdown of the restorative margins, any loss of cement, or any effect on the enamel. No significant treatment effect on the orthodontic bracket or crown retention force was found (ANOVA, p > 0.05). CONCLUSION: The new Ultrasound toothbrush was found to be safe on natural tooth surfaces and restorative materials, as established in comparison to positive and negative controls. Furthermore, no safety concerns related to orthodontic bracket or dental crown retention were identified with any treatment.

Synergistic use of ultrasound and sonic motion for removal of dental plaque bacteria.

Proving that an idea has merit for further investigation is one of the earliest steps in product development. This proof of concept can be effectively studied in a dynamic, multidisciplinary environment where ideas can be quickly tested in a manner related to final product use. In this article, the authors demonstrate the fecundity of a multidisciplinary environment by reviewing their early work that shows that ultrasound could be added to a power toothbrush to enhance the removal of dental plaque bacteria. They hypothesized that sonic brush head motion would generate bubbles in a dentifrice so that ultrasound beamed into that slurry would cause those bubbles to expand and contract in a manner that would dislodge the plaque bacteria adherent to the tooth surfaces. In this work, Streptococcus mutans bacteria adherent to various surfaces was used as a model of dental plaque on human teeth. Prototype power toothbrushes were created using commercially available and custom components so that the ultrasound and sonic processes could be individually modified and applied. Research demonstrated that the combination of sonic and ultrasound processes could synergistically remove S mutans biofilm. This finding established the proof of concept that eventually led to the development of a power toothbrush that uses both ultrasound and sonic activity.

In vitro evaluation of the efficacy and safety of the intelliclean system: interproximal biofilm removal and dentin substrate wear.

The ability of a novel integrated power toothbrush and liquid-toothpaste dispensing system, the IntelliClean System from Sonicare and Crest, to remove interproximal biofilm while being gentle on dentin was studied using two in vitro models. Interproximal biofilm removal was assessed via a complex multispecies biofilm grown on hydroxyapatite disks and then placed interproximally in a typodont section modeling a typical oral environment. The power toothbrush in the prototype integrated system was compared to a traditional rotating/oscillating power toothbrush, the Oral-B ProfessionalCare 7000, and a nonbrushing control through a series of 3 experiments with a total of 36 replicates per arm. The amount of interproximal plaque biofilm removed by the integrated system toothbrush was significantly greater than that removed by the rotating/oscillating toothbrush and by the nonbrushing control (P < .05). In the second model, dentin substrate wear was measured using profilometry after the brushing of dentin sections (3 mm x 10 mm) for a period equivalent to 2 years of typical product use. Dentin wear associated with the use of the prototype integrated system with standard and whitening versions of the liquid toothpaste was compared to that of a rotating/oscillating power toothbrush and a manual toothbrush with the standard version of the prototype liquid toothpaste, with a total of 12 replicates per arm. The amount of dentin wear induced by the integrated system with either the standard or whitening liquid toothpaste was significantly less than the wear from the rotating/oscillating power toothbrush and the manual toothbrush with the standard liquid toothpaste (P < .05).

Designing the next generation of a sonic toothbrush.

With the goal of aiding consumers' ability to achieve better oral health, oral hygiene products continue to evolve. Powered toothbrushes are an increasing part of this oral hygiene effort. This article summarizes the clinical and sensory testing associated with the Sonicare Elite, a new generation of sonic toothbrush. Important aspects of brush design such as bristle motion, head and neck shape, bristle configuration and trim, ergonomic design, and user interface are discussed. Further, the article discusses the mix of objective clinical and laboratory tests and subjective sensory and consumer tests that are utilized to ensure the product design meets the consumer's desire to achieve better oral health in a manner that is both pleasing and effective.