Perio(dontics

Clinical evaluation of an ionic toothbrush in the removal ofestablished plaqne and reduction of gingivitis

Ronald L, Van Swol*/Donald E. Van Scotter**/Jeffrey J. Pucher***/Andrew R. Dentino'

Abstract The clinical effectiveness of a manual Ionic toothbrush in the removal of dentalplaque and the reduction of gingivitis was evaluated. A double-blind studyevaluated the effect of a small, imperceptible electric current on established dentalplaque and gingivitis during loothbrushing. Sixty--four adults completed the study.Gingivitis and plaque scores were determined at baseline and after 3 and 6 months.The baseline indices of the nvo groups were well balanced. At each exainlnaiion, theparticipants were instructed how to hold the toothbrush properly arid retninded tochange brush heads every 4 weeks. Statistically significant iinprovemems in LoeGingival Index scores were observed from baseline to 6 months between the controland test groups and within the test group. The Quigley-Hein Plaque Index scoresalso showed a significant improvement from baseline ¡o 6 months between thecontrol and test groups and within Ihe test group.(Quintessence Int ¡996:27:389-394:)

Clinical relevance

By using the ionic toothbrush conscientiously on adaily basis, the compliant patient can removesignificantly more plaque tban with other tooth-brushes, reducing the risk of gingival inflammationand caries.

Introduction

For many years, people have used various methods forcleaning their teeth. The most primitive method wasthe use of various types of wooden stick. The mahireason for tooth cleaning in years past was the removalof food particles that caused oral discomfort, while oral

* Professor and Director. Division of Periodontics, Marquette Uruver-sity, School of Dentistry, Milwaukee. Wisconsin.

** Adjunct Professor. Division of Peri o don lies. Marquette University,School of Dentistry, Milwaukee, Wisconsin.

•"• Assistant Professor. Division of Periodontics. Marquene tjniversity,School of Dentistry, Milwaukee. Wisconsin.

Reprint requests; Dr Ronald L. Van Swol, Division of Periodontics,Marquette University, Sctiool of Dentistry, PO Box lS8t, Milwaukee,Wisconsin 532O1-IS81.

hygiene today is specifically directed toward plaquecontrol.' Today, toothbrushing is the most widelypracticed method of oral hygiene and has a very highdegree of social acceptability.- It bas been shown that,in industrialized countries, 80% to 90% ofthe popula-tion brush their teeth one or two times a day.̂ ''* It hasbeen fiirtber sbown that the toothbrushing practiced bythe majority of these people is unsatisfactory, if the goalis plaque controi. An average daily brushing ofapproximately 2 minutes' duration will remove onlyhalf the accumulated plaque, leaving the other half topromote rapid regrowth." This finding was supportedby another study, in whicb it was sbown that theaverage person, by brushing, removes only about 50ÏSof the plaque present on his or her teeth.^

In an effort to increase the amount of plaqueremoved at each brushing, toothbrushes of differentsizes and shapes and made of various materials havebeen developed. Brushes with soft bristles, multituftedheads, and end-rounded filaments have been intro-duced. In addition, many electric-powered tooth-brushes have been developed. Generally, the manualand electric toothbrusbes are equaUy effective inremoval of bacterial plaque.' In spite of all tbis activityin improving toothbrush type and design, most peoplestill remove oniy about 50% ofthe plaque present when

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they brush their teeth,^ The development of a tooth-bmsh that would allow the average person to removemore plaque from his or her teeth on a daily basis ishighly desirable.

In an effort to achieve better plaque removal, amanual ionic action toothbrush was developed. Thepurpose of this study in humans was to evaluate theeffectiveness of the hyG ionic toothbrush (HukubaDental) in removing dental plaque and reducinggingivitis.

Principies of the Ionic Action Mechanism

A basic understanding ofthe ionic action mechanismis essential. The use of devices with ionic action in theoral cavity is not a new concept. The terms ionto-phoresis, electmphoretic. and electmionlzinghave heenused synonymously in dentistry for many years,^""Ionic activity was a concept originally developed forChe desensitization of natural teeth. Pratt'' patentedthe idea in 1889.

The mechanism for the ionie aetion is due to achange in the polarity ofthe teeth. Teeth are normallynegatively charged and plaque is positively charged.Opposite charges attract and bond to each other.Plaque, therefore, is attaehed to the tooth surface byionic bonding.'^

The hyG toothbrush has a 3-V lithium batterylocated under the metal band on the handle. Thebattery is similar to a watch battery and just as safe. Thetoothbrush bristles are negatively charged through themetal rod within the brush head. When the metal bandon the toothbrush handle is held with moistenedfmgers, the positively charged ions are transferred tothe teeth during brushing. The tooth polarity changesfrom negative to positive. The positively charged toothions repel the positively charged plaque ions. Thepositively charged plaque ions are then attracted to thenegatively charged bristles ofthe hyG toothbrush. Thisimportant ionic exchange, along with the normalmechanical action of the bristles on the toolh andgingival surfaces, may enhance plaque removal.

Contact of moist fingers with the metal band on thehyG toothbrush handle is essential to maximize ionictransfer of plaque molecules between the teeth and thetoothbrush bristles. Laboratory studies have shownthat the actual current circulation from the 3-V lithiumbattery is 1.5 V at the teeth when the brush is held withmoistened fingers. The current is only 0.8 V when thebrush is held with dry fingers.'""

Method and materiais

Adult male and female subjeets were selected from thefaculty, staff, and general patients at Marquette Univer-sity, School of Dentistry. All potential subjects werethoroughly screened, and those who participated wererequired to meet the following qualifications:

1. They completed a Confidential Health Question-naire.

2. They signed an informed consent form that wasapproved by the Institutional Review Board atMarquette University.

3. They were dental piaque formers, as demonstratedby a elinical examination.

4. They were not taking any medication or usingmouthwashes that could have an inhibitory effecton formation of dental plaque.

5. They had a minimum of 20 natural teeth.6. They agreed to return for periodic examinations at

3 and 6 tnontiis following the recording of baselinedata.

The Intent of this study was to emoll 65 to 70patients who met these criteria. Three examiners weretrained by the principal investigator in the clitiicalindices to be used and were tested for intraexaminerand interexaminer reliability. A high level of reliabihtywas achieved.

The Loe Gingival index'^ was used to evaluategingival inflammation. The gingivai tissues weredivided into two gingival scoring units, namely thelabial/buccal and lingual/palatal surfaces. Criteria forscoring were as follows: 0 - normal gingiva; 1 - mildinflammation—slight change in color and slight edema,but no bleeding on probing; 2 = moderate inflamma-tion—redness, edema, and some glazing, but nobleeding on probing; and 3 = severe inñammation-marked redness, edema, and bleeding on probing.

The Quigley-Hein Plaque Index '* was used to assessdisclosed plaque on the labiai/buecal and lingual/palatal tooth surfaces; 0 = no plaque; 1 = separateflecks of plaque at the cervical margin ofthe tooth; 2 =a thin continuous band of plaque (up to 1 mm) at thecervical margin ofthe tooth; 3 - a band of plaque widerthan 1 mm but covering less than one third of thecrown ofthe tooth; 4 = plaque covering at least onethird but less tlian two thirds ofthe crown ofthe tooth;and 5 = plaque covering two thirds or more of thecrown ofthe tooth.

Seventy-one subjects were selected for the study.Each received a complete-mouth gingivai exatnina-

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tion. After each tooth area was scored according to theGingival Index, subjects were given a liquid disclosingsolution and instructed to rinse for 15 seconds. Plaquescores were then determined and recorded.

The subjects were given a prepackaged and codedhyG ionic action toothbrush (Fig 1 ), The toothbrusheswere received evenly divided (36 of each) betweenthose that had active batteries and those that hadinactive batteries. Each packet had a code number thatwas recorded for the subject at the time of deliveryNeither the researchers nor the subjects knew whethertheir toothbrush contained an active or inactivebattery.

Written instructions were given, and the subjectswere shown how to hold the toothbntsh properiy sothat their moist fingers touched the metal band duringtoothbrushing. Subjects were told to brush at leasttwice daily using their usual technique and dentifrice.They were lltrther advised not to use any oral rinsesthat could affect plaque inhibition during the course ofthe study Additional toothbrush heads with softmultitufted 0.18 diameter nylon bristles were dis-pensed. Subjects were instructed to change brushheads every 4 weeks. They were then scheduled for anappointment for the next scoring session, approxi-mately 3 months from the date of the Initial exam-ination.

At the 3-month examination, the gingival inflam-mation scores were determined and recorded. Eachsubject was given disclosing solution, and the plaqueaccumulations were scored and recorded. During thecourse of the examination, the subjects were observedto assure the safety of the toothbrush assigned to them.The safety assessment included examination of thetongue, hard palate, soft palate gingiva, oral mucosa,sublingual space area, tooth structure, dental restora-tions, and cervical root areas. They were questionedregarding any adverse reactions to their assignedtoothbrush. Each subject was again instructed to holdthe toothbrush properly and to change brush headsevery 4 weeks. They were given an appointment for thefinal exatnination, approximately 6 months frombaseline.

Subjects returning for the 6-month, or final phase,of the study were again observed and questionedregarditig the safety of their toothbrush. The gingivalinflammation and plaque scores were determined andrecorded. The subjects were informed that the studywas completed.

All data were statistically analyzed with Statview512 computer software (Brainpower). The statisticalsigtiificance of the data for the Gingival Index and

Fig 1 Electronic toothbrush evaitja-ted Metai pad (arrow), or terminai,must iiave linger or palm contact.

Table ! Demographic data of subjects

No,Female-male ratioAverage age (ys)Age range (ys)

Group A(test)

3430:432,4718-60

Group B(control)

3025:533,2019-67

Plaque Index within a group was determined with the ttest.

Results

At the completion of the clinical phase of the study, thecodes denoting toothbrushes with or without an activebattery were received from the sponsor. Based on thecodes, subject data were divided into two groups forevaluation and statistical analysis. Group A includedthose subjects who received a toothbrush with anactive battery. Group B included those who received atoothbrush with an inactive battery. Table I presents

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Table 2 Mean (+ SD) changes in plaque and gingival indices with use of an ionic toothbrush

Baseline3 Mo6 MoDifference (3 Mo)Difference (6 Mo)

Baseline3 Mo6 MoDifference (3 Mo)Difference (6 Mo)

Group A (test)(n = 34)

Group B (control)(n - 30) Significance

Plaque Index

1.76 + 0.501.26 ± 0.461.13 ±0.44*0,50 ±0.040.63 + 0.06

Gingival Index

1.71 ±0.560.87 ±0.340.82 + 0.40*0.84 ±0.220.89 + 0.16*

2.00 ±0.541.38 ±0.331,63 + 0.540.62 ±0.210.37 ± 0.00

1.68 ±0.500.91 ± 0.361.18 + 0.510.77 ±0.140.50 ±0.62

NSNSP=.OO]NSP<.QS

NSNS/»-.OOlNSP< .QS

' SiatiSLically significantNS - not significant.

the demographic data of the subjects in the study Ofthe 71 selected subjects, 64 completed the study. Sevensubjects were eliminated from the study and theirscores were not included in the final analysis. Of these,four did not use their assigned toothbrush exclusivelyduring the test period, and three took physician-prescribed antibiotics.

The results of the study are presented in Table 2. Thebasehne indices of the two groups were well balanced.Mean Löe^^ baseline gingival scores of 1.68 to 1.71were determined for the control and test groups,respectively. A statistically significant improvementwas observed from baseline to 6 months between thecontroi and test groups. There was also a statisticallysigniftcant improvement within the test group frombaseline to 6 months. The overall improvement ingingival health was 51.87% for the test group and30.18/S for the controi group.

Mean Quigley-Hein'^ baseline plaque scores of 2.00and 1.76 were found for the control and test groups,respectively. The scores indicated a statistically signif-icant improvement from baseline to 6 months betweenthe control and test groups. The test group had a36.17% reduction in plaque, compared to only 18,56%for the control group. This means that the test groupehtninated 48.69% more plaque than did the control

group. There was also a statistically significant im-provement within [he test group from baseline to 6months. Figures 2 and 3 iUustrate the significantimprovement observed during the course of the6-month test.

Discnssion

This double-blind clinical smdy evaluated the effect ofa small and imperceptible electrical current on estab-lished human dental plaque and gingivitis duringtoothbrushing. The hyG ionic action toothbrush usedin the study has a 3-V lithium battery (Panasonic,Hitachi, or Sony) that supplied a positive electricalcharge to the metal band on the handle and a negativecharge to the bristles. The body, which is electricallyconductive, serves as a conduit for the electrical chargeto the teeth.

When the toothbrush is held in the moist hand andthe bristles of the toothbrush head contact the targetteeth or gingiva in the presence of saliva, an imper-ceptible electrical circuit is energized. The salivabecomes the electrolyte in which ions commence theirselective motion." This electron fiow temporarilyreverses the polarity of the contacted teeth to a positivecharge. It allows a break in the ionic bonding between

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TIME (Moniha)

Fig 2 Changes m Plaque Index over lime. Group A:Toothbrush with active baltery, Group B: Toothbrush withinactive baltery.

riME (MonihaJ

Fig 3 Changes in Gingival Index ovet time Group A:Toothbrush with active battery, Group B' Toothbrush withinactive battery.

the teeth and the plaque. The plaque is then attractedto the negatively charged bristles of the toothbrush,which may enhance removal of the plaque,'^

The results of the study revealed a statisticallysigtiiñcant beneficial effect in lower plaque and gingi-vitis scores after 6 months. These findings contradictthose of a study by Van der Weijden et al, " who foundno beneficial effect. Their study was similar, although itran for only 5 montlis instead of 6 months. Theircurrent source was two 1.5-V batteries. An importantdifference may be their toothbrush design. The tooth-brush tested in the present study was designed formanual use, while the toothbrush used in the Van derWeijden study'^ was designed to deliver both anelectric current and make a vibrating motion. Thebulky design of their toothbrush handle would seem tomake manual use difficult. The toothbrush was testedwith the vibrating action switched off, which givescredence to the theory that manipulation was difficult.In addition, they used only a half-mouth scoringdesign, and we used a complete-mouth scoring design.

No effort was made to change the subjects' brushinghabits, although they were instructed to hold thetoothbrush properly. They were also told to use onlytheir assigned toothbrush for the duration of the study.At the 3-month examination, the proper use of thetoothbrush and the importance of maintaining thetwice-a-day level of brushing were again emphasized.

Specifically, patients were told that the brush handleshould be moist and that the thumb or fingers mustcontact the metal band (see Fig 1),

In the present study, statistically significant changesin the plaque and gingivitis scores were not observed at3 months; however, the mean scores were lower in thetest group. This indicates that the subject could expectsignificant improvement over time. It is probable thatstatistical significance was not evident at 3 monthsbecause of the Hawthome effect,-" That is, subjectstend to show immediate improvement in both controland test groups because of high interest and motiva-tion. With time, interest wanes, and subjects tend toreturn to their usual brushitig practices. This undoubt-edly occurred between the 3- at:d 6-month visits.Improvement in plaque and gingival scores recorded at3 months may in part be attributable to the high level ofcompliance of both groups early in the study. However,by the end of 6 months, all subjects are likely to revertback to their former brushing habits. Thus at 6 months,the benefits of the ionic actiort were evident at astatistically sigtiificant level.

This possibility is supported by the rebound inplaque and gingival scores that was observed in thecontrol group but not in the test group. This wouldindicate that the ionic action of the hyG toothbrush iseffective and helped subjects with average oral hygienepractices accomplish better overall plaque removal.

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CoDclusions

The results obtained in tbe study demonstrate tbeeffectiveness of an ionic toothbrusb with a 3-V battery.The removal of plaque and the reduction of gingivitiscan be enhanced by tbe use of the hyG ionic actiontoothbrush in personal oral hygiene care. The hyGionic action toothbrush is a safe and effeetive oralcleansing device when used unsupervised on a regularbasis for the removal of human dental plaque.

AcknowledgmentThis investigation was supported by a grant from Hukuba DentalCorporation, 9t4-l Naïukari, Nagareyamacity. Chiba, Japan.

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