Comparison of sonic and ionic toothbrush in reduction in plaque and gingivitis.

BACKGROUND: A paucity of conclusive research exists on the optimal design and mode of action of toothbrushes, leading to the introduction of new generation of toothbrushes. Sonic and ionic toothbrushes belong to this new generation of toothbrushes. The aim of the present study was to clinically assess and compare the efficacy of the sonic and ionic toothbrushes.
MATERIALS AND METHODS: A single blind study, using a split-mouth method, was conducted for 45 days on a total of 22 (11 males and 11 females) student volunteers, with age of 17 to 21 years. Plaque, gingival, and bleeding indices were recorded after every 15 days.
RESULTS: Both the toothbrushes showed significant reduction in all three parameters. However, the sonic toothbrush proved to be more effective than the ionic toothbrush on the percentage basis, the difference in parameters was statistically nonsignificant.
CONCLUSION: It may be concluded from the present study that though the sonic toothbrush was insignificantly superior to the ionic toothbrush, both the toothbrushes are clinically effective in removing plaque and improving the gingival conditions.

“Correct and routine toothbrushing will soon iron out, so to speak, all the irregularities in, and restore normal colour and contour to, the gingivae …… thus, since the toothbrush may also readily aid in the resolution of these incipient symptoms, its potentiality in their prevention is evident.”

INTRODUCTION

Although there have been many advances in knowledge of the causes of human periodontal diseases, plaque remains the primary initiator or trigger.[12] Removal of dental plaque is essential for dental health[3] and personal oral hygiene is necessary for maintaining periodontal health.[4] Though there are various methods, including chemical and other mechanical methods advocated for this purpose, toothbrushing is the most commonly used method.[5]

Various forms and designs of powered toothbrushes have been introduced in world market since 1960s with varying efficiency, acceptability, and popularity. The mode of action of these brushes is designed to simulate the manual toothbrushes, but they have established themselves as a superior alternative to manual toothbrushes as they are much more attractive and user-friendly.[6] However, clinical studies have proved that manual and electric toothbrushes are equally effective in removal of plaque and reducing clinical signs of gingival inflammation.[7]

More recently, two unique toothbrushes, Sonic (hyG, Hukuba Dental, Nagareyama, Japan) and Ionic (Cybersonic, Florida, USA), have been introduced to market, to further improve plaque-removing efficacy. The aim of present study was to clinically assess and compare efficacy of sonic and ionic toothbrushes in reducing plaque, gingivitis, and sulcular bleeding.

MATERIALS AND METHODS

Screening and selection of subjects

A total of 22 student volunteers of first-year Bachelor of Dental Surgery BDS (11 males and 11 females), with age of 17 to 21 years (mean age – 18.8+1.02), were screened, selected, and stratified, according to inclusion and exclusion criteria by a second examiner Dr. A.

Inclusion criteria consisted of subjects:

with good general health,

without any systematic diseases,

with disease known to affect oral tissues,

who had not received any periodontal therapy for past 3 months,

who had not taken any antibiotics or antiseptic mouthwashes since last one month prior to study,

with full complement of teeth, except third molars,

with ability to attend hospital at recall intervals.

Exclusion criteria consisted of subjects:

with orthodontic appliances,

using any other supplemental plaque control methods,

with five or more carious teeth requiring immediate treatment,

with mucogingival problems like high frenal attachment,

with manual dexterity conditions,

who were taking drugs that could affect state of gingival tissues including corticosteroids and nonsteroidal anti-inflammatory drugs.

Material used

Sonic (hyG, Hukuba Dental, Nagareyama, Japan) and Ionic (Cybersonic, Florida, USA) [Figures 1 and 2].

Figure 1

Sonic toothbrush

Figure 2

Ionic toothbrush

Study design

A single blind study, using a split mouth method, i.e., using sonic on one side's upper and lower arch and ionic on other side's upper and lower arch, was designed. The study was designed for 45 days and indices were recorded after every 15 days (0, 15, 30, and 45 days).

Consent for participating in the study was taken from all volunteers. Baseline scoring of plaque index (PI)[8] using a two-tone disclosing agent (Alpha Plac), modified gingival index (MGI),[9] and gingival bleeding index (GBI)[10] was done. The volunteers had not yet started brushing with the given brushes.

Instructions were given to use only the given brushes on assigned sides twice daily for 3 minutes by the assigned toothbrushing technique, with assigned dentifrice (Colgate Total (R)) only. Volunteers were asked to refrain from brushing 24 hours before every recall visit and return for periodic examination after every 15 days, that is, on 15th, 30th, and 45th days till the end of study. During each recall visit, plaque, gingival, and bleeding indices were scored. Only Dr. A. knew on which side each of the brush was used, and was not involved in clinical scoring of indices. Compliance and comments about brushes were determined by a questionnaire at each recall visit. Also, instructions, including the brushing technique, were reinstated at each recall visit.

Statistical analysis

Intragroup comparisons were analyzed by paired t test and intergroup comparisons of reductions in various clinical parameters between two groups were analyzed by Mann-Whitney test. P value of <0.05 was considered statistically significant.

RESULTS

Modified gingival index

Mean reduction in MGI scores for both the brushes has been shown in Table 1. Though the sonic toothbrush was better in result on 15th day and at the end of study, the ionic toothbrush showed more reduction on 30th day. On intergroup comparison, the difference in P values (P value - 0.37, P value - 0.37, P value - 0.53, P value - 0.92, and P value - 0.18, respectively) was found to be statistically nonsignificant for 0-15th, 0-30th, 0-45th, 15th-30th, 30th-45th day intervals.

Table 1

Comparison of reduction in gingival index at different time intervals

Plaque index

As shown in Table 2 the ionic toothbrush showed more reduction on 15th and 30th day, while both the toothbrushes showed almost same reduction on 45th day. P value - 0.78, 0.27, and 0.94 for the respective time intervals was again found to be statistically nonsignificant. Also, P value - 0.82 and P value - 0.69, respectively for 15th–30th day and 30th–45th day intervals, was found to be statistically nonsignificant.

Table 2

Comparison of reduction in plaque index at different time intervals

Gingival bleeding index

As shown in Table 3, reduction in GBI was more in case of sonic toothbrushes at the end of the study (45th day), while, the ionic toothbrushes showed more reduction on 15th and 30th day. The difference in P values (P value - 0.72, P value - 0.67, and P value - 1.00, for 15th , 30th , 45th days respectively) was found to be statistically nonsignificant. Also, for the time intervals 15-30 days and 30-45 days, the difference in P values (P value - 0.15 and P value - 0.61, respectively) was found to be statistically nonsignificant.

Table 3

Comparison of reduction in bleeding index at different time intervals

DISCUSSION

Sonic toothbrush operates at 31 000 brush strokes per minute (260 Hz), ten times more than electric toothbrushes [Figure 3]. The generated sonic waves create high-speed scrubbing strokes that can remove plaque from subgingival and interdental areas. Cavitational effect, fluid streaming, and acoustic vibrations [Figure 4], which may cause hydrodynamic stresses, may also aid in dislodging microbial plaque.

Figure 3

Components of sonic toothbrush

Figure 4

Cavitation and acoustic streaming

Use of devices with ionic action in the oral cavity is not a new concept. The terms iontophoresis, electrophoresis, and electrolyzing have been used in dentistry for many years. Ionic toothbrush is only slightly larger than the manual toothbrush, with replaceable brush-heads [Figure 5], and works on the principle of changing surface charge of tooth to repel plaque even from inaccessible areas of teeth [Figure 6]. It is also speculated that the activated anions might inhibit coupling between the pellicle and bacteria, mediated by calcium bridges. The important ionic exchange, along with the normal mechanical action of the bristles on the tooth surface, enhances plaque removal.

Figure 5

Parts of ionic toothbrush

Figure 6

Parts of ionic toothbrush

The study was designed to be a single blind study, thus reducing the bias error. Split-mouth study was designed to reduce interpatient difference and made sure that similar conditions apply for both the brushes. Heasman and Mc Craken[11] considered split-mouth study of greatest value for evaluation of plaque-removing efficacy, especially for powered toothbrushes.

One problem in the design of short-term brushing studies is that the amount of plaque to be removed may decrease in the course of study due to motivation and brushing experiences.[1213] To avoid such problems, we chose to use a standardized period of at least 24 hours of plaque accumulation before each recall visit. This might have also reduced the “How thorne effect?,” that is, the patients brush more consciously on the day of recall.[14]

In a short-term clinical study, many different factors such as duration of toothbrushing, manual dexterity, motivation, frequency of toothbrushing, technique and thoroughness of toothbrushing, type of dentifrice (Colgate Total®) being used, regularity and punctuality of follow-up appointments, and “novelty-effects”[15] may interfere with results. On the other hand, lack of interest on the part of participants and increased number of drop-outs in case of long-term studies can lead to frustration of examiners and an overall affect on the results.[11]

Subjects using any additional plaque control measures like interdental cleansing aids and mouthwashes were not selected because it could have affected the outcome of this study. Third molars were not included because of the difficulty in visibility and accessibility. Subjects wearing orthodontically bound appliances, removable or fixed prosthesis, or having grossly destructed teeth were also not included because of asymmetrical pattern of plaque formation in these patients and also these iatrogenic factors may annoy their users by greater propensity to fray.

Brushing twice daily at 10- to 12-hour interval has been advised, since early plaque is more vulnerable to mechanical action.[16] The duration of toothbrushing has an almost linear monotonic effect on plaque reduction, which may vary between 30 seconds to 8 minutes.[17] As a result, the possible differences between toothbrushes may be obscured. Hence, we decided to standardize the minimum brushing time for optimum plaque removal, that is, 3 minutes twice daily as suggested by Pader.[18]

Findings of this study show significant reduction in gingivitis with the use of sonic toothbrush, which were in accordance to other studies.[719-24] Tritten and Armitage[23] reported sonic toothbrushes to be superior to manual toothbrushes in removing supragingival plaque, probably because of the better compliance toward these brushes;[202425] however, contradictory findings were reported by others.[26-30] Also, mean reduction in GBI scores were in accordance to O’Beirne et al.[22] and other studies.[20233132]

Our results confirm findings of other previous studies by Maki et al.[33] and Van Swol et al.[34] that reported a significant reduction in gingival index using ionic toothbrush. Electrically charging tissue, in addition to mechanical plaque removal by ionic toothbrush, might show additional improvements in gingivitis.[35] Toshihoro et al.[36] stated that anions might be activated that inhibit coupling between pellicle and bacteria, mediated by calcium bridges. This may result in its effectiveness in removing plaque. Plaque-removing effect of ionic toothbrush has also been reported by various other authors.[21333738] Ionic toothbrush was found to have no beneficial effect on gingiva and plaque in at least one study, probably, because of the bulky design of the brushes used in that study, which were designed to have vibratory action in addition to current transfer. This vibratory action was switched off during their study, indicating some difficulty in manipulation.[39]

There was no ulceration or gingival ablation noticed by use of either of the brushes. A slight increase/less reduction in parameters were seen between 30th and 45th day for both brushes. This may be attributed to gradual reduction of initial novelty effect[37] and/or Hawthorne effect.[14]

Although brushes have shown almost same reduction in PI, slight difference in gingival and bleeding index may be attributed to efficacy of sonic toothbrush to disrupt subgingival plaque with fluid dynamic activity generated by them,[40] in addition to supragingival plaque.[41] Fluid dynamic activity generated by sonic vibrations has been shown to remove microbial plaque formed in vivo,[4042] even at a distance of 3 mm beyond its bristle tips, thus having some effect on subgingival plaque also, although effect of these phenomenon in thick medium of saliva and toothpaste are debatable. The comparatively less precise method of scoring these indices, especially MGI which is based only on observation of gingival color and consistency by examiner, may also account for such difference.

Some better results by sonic toothbrush may also be explained by greater compliance shown by volunteers toward this toothbrush in comparison with ionic toothbrush. The subjects found sonic toothbrush much easier to use as they had to apply less force, probably because of adjunctive vibrations. As the subjects applied lesser force for sonic toothbrush, lesser wear of bristles was seen in sonic toothbrush in comparison with ionic toothbrush.

Superiority of sonic toothbrush may be attributed, in part, to novelty-effect, as sonic toothbrush was different in design and mode of action, while ionic toothbrush was more like any other manual toothbrush. Though ionic toothbrush also has a new mode of action, it does not make much difference to the subject while brushing.

CONCLUSION

During this 45-day clinical trial, no adverse effects were found or reported for both brushes. Based on the data, this study demonstrates that both sonic and ionic toothbrushes are capable of removing plaque and reducing gingivitis and bleeding effectively. The results show that the sonic toothbrush showed better results as compared with the ionic toothbrush, though the difference was statistically insignificant.