Journal of Oral Hygiene & Health
Open Access

Oral Hygiene; Dental Plaque; Gingival Health; Tooth brushing; Customized Home Care

Introduction

Oral health-related quality of life is an integral part of general health and well-being. Good oral hygiene contributes to improved quality of life by reducing oral pain, preventing disease progression, and supporting overall physical and psychosocial well-being [1-3]. Poor oral health has been linked not only to dental caries and periodontal disease but also to systemic conditions such as cardiovascular disease, diabetes, and adverse pregnancy outcomes [4, 5]. Maintaining effective oral hygiene practices reduces the microbial burden in the oral cavity and lowers the occurrence of dental diseases [6]. Oral hygiene typically includes the use of a toothbrush and toothpaste; however, the effectiveness of oral hygiene practices depends on patient compliance, manual skill and motivation.

Tooth brushing is consistently characterized by uneven distribution of brushing time across tooth surfaces. Studies have shown that individuals spend a disproportionate amount of time brushing the buccal surfaces of the maxillary anterior teeth [7, 8]. Dental professionals recommend brushing for 2 minutes, twice a day. However, observation of brushing behavior suggests brushing occurs for less than 1 minute [9, 10].These findings with respect to uniformity and duration of brushing underscore the importance of oral hygiene instruction and technological interventions designed to promote balanced brushing [11].

Recent advances in technology provide the opportunity to create a unique oral hygiene device specific to each user. Intraoral scans that are now common in dental offices provide accurate three-dimensional representations of the dentition. The combination of these scans with 3D printing allows the generation of a device that conforms closely to the tooth surface. ZERO brush Inc. has utilized these technological advances to create a full-mouth power toothbrush with a mouthpiece that is custom fit to the dental anatomy of each user. The objective of this study is to evaluate the clinical performance of ZERO brush’s device in comparison to a manual toothbrush and to gain consumer insight into its acceptance.

Materials and Methods

This comprehensive evaluation of a ZERO brush full-mouth power toothbrush (ZBPT) with a custom-fit mouthpiece consisted of both a consumer research study that evaluated the toothbrush’s consumer acceptance and a clinical study that evaluated its efficacy and safety.

Consumer Research Study

The consumer research study was a 2-week home-use test placed from a central location (Various Views Research, Blue Ash, OH) using 101 adult individuals who expressed positive purchase intent to the ZBPT concept and did not meet any study exclusion criteria. Qualifying individuals obtained a full-mouth digital scan of their dentition. This scan was used to create a toothbrush mouthpiece unique to the participant. When the mouthpiece was complete, participants picked up their ZBPT test kit which included the custom mouthpiece, a handle, a charging stand, a quick-start guide, one tube of toothpaste (Crest 3DWhite, Procter & Gamble, Cincinnati OH USA), and a Snap-On toothpaste dispensing cap to aid application of the toothpaste to the mouthpiece. Participants unboxed, assembled, and turned on their ZBPT at the research facility. After 14-days of in-home use, participants completed an online survey about their experience.

Clinical Study

The clinical study was a prospective, randomized, examiner-blind, 2-arm parallel, 4-week evaluation of efficacy and safety of two oral hygiene devices. The study was approved by an accredited IRB (Sterling IRB, Atlanta GA, and IRB00001790) and executed at a single site (Complete Health Dentistry, Blue Ash OH). All subjects were recruited from the pool of participants in the previously mentioned consumer research study and thus had the ZBPT custom-fit mouthpiece previously made. The primary objectives of this study were the evaluations of dental plaque reduction and device safety. Secondary objectives included the evaluation of gingival health and recession after 4-weeks of in-home use.

The number of subjects was based on a parallel design study assuming a difference in the plaque score of 0.30 between the two toothbrushes and a common standard deviation of 0.40. A sample size of 56 subjects (28 per treatment group) was calculated to provide 80% power to detect a statistically significant difference in reduction in the plaque score with a significance level 0.05 using a two-sided two-sample equal-variance t-test. Due to possible attrition, up to 32 subjects in each group were planned for enrollment.

The study contained 3 subject visits to the dental clinic. During the first visit subjects were screened for enrollment criteria and consented. Enrollment criteria included a willingness to abide by study oral hygiene requirements, overall good general health, and evidence of mild to moderate plaque buildup without significant calcification. Exclusion criteria included significant decay, periodontal disease or active orthodontic treatment. Subjects who were enrolled received a manual toothbrush and toothpaste for a 7-day washout period before the Baseline visit.

At the Baseline visit (Visit 2) subjects were randomization to one of two treatment groups: ZBPT group = ZERO brush use for 30 s, or MTB group = manual toothbrush use for 60 s. Subjects received an oral exam, a full mouth digital scan (iTero Lumina, Tempe AZ, USA), a gingival bleeding assessment [12], measurement of gingival recession, and pre- and post-brushing plaque assessments using the Turesky Modified Quigley Hein Plaque Index [13]. Between the pre- and post-brushing assessments the subjects used their assigned oral hygiene device. Subjects returned for a post-use clinical evaluation (Visit 3) after using their assigned device at home for a 4-week period. Adverse events based on the oral exam and patient reporting were recorded at each Visits 2 and 3 to assess safety.

The plaque scores for each subject were analyzed to obtain mean subject plaque scores for both the whole mouth (overall) and sub regions of the dentition. The analysis yielded a pre-brushing mean plaque score and post-brushing mean plaque score for each subject using their assigned device. A percent reduction between the pre-brushing plaque score and the post-brushing plaque score was calculated for each subject and subsequently used to determine group averages for each device. A single-factor ANOVA was used to test for statistically significant treatment differences between the two groups. Similarly, changes in plaque levels were analyzed between the Baseline and Week 4 visits for both pre- and post-brushing scores. Gingival bleeding and recession measures were scored by the examiner during the clinical visit whereas the inflammation measure [14] was scored after the visit from the scanned images of the dentition and gingiva. Changes in bleeding, inflammation and recession were analyzed between the Baseline and Week 4 visits. A single-factor ANOVA was used to test for statistically significant treatment differences between the two groups’ change scores from baseline.

Results

Consumer Research Study

One hundred one participants completed the consumer research study. The average age of participants was 48.9 years (range: 23-70, SD = 11.27). There were 85 females (84.2%) and 16 males (15.8%) who participated. At the conclusion of the 14-day home use, 66% of participants rated ZBPT better than any toothbrush they had ever used, and 89% wanted to continue to use it. Attribute-level results include: 74% agreed ZBPT delivered a superior clean feeling every day; 76% agreed it was a gentle, comfortable brushing experience; 75% agreed it is the most effortless way to brush; and 73% agreed it simplifies their brushing routine.

Clinical Study

The clinical study demographic data for all enrolled subjects are presented in [Table 1]. The average age for all study participants was 47.9 years with a gender composition of 84.1% female and 19.9% male. There was no statistical difference between the ZBPT and MTB groups for either age or gender. Sixty-three subjects completed the Baseline visit (n=32 in the ZBPT group and n=31 in the MTB group). By the Week 4 visit there remained one subject fewer in each group: one lost to follow-up and the other to study non-compliance.

(A): ZBPT = ZERO brush power toothbrush; MTB = Manual toothbrush

(B): p-value is based on one-way ANOVA for continuous variables and Chi-squared test for categorical variables

Table 1: Clinical Study Demographic Characteristics: All Randomized Subjects

Summary plaque removal data for the single brushing event is presented in [Table 2] for the Baseline visit for the two treatment groups. There were no statistical differences in the overall pre-brushing plaque levels between the two groups (p=0.5000) nor for any of the sub-regions (p>0.22) at Baseline. For both treatments the within-group reduction from pre-brushing to post-brushing was statistically significant (p<0.0001). There was a 54.8% reduction in the plaque score for the ZBPT group from pre-brushing to post-brushing and a 29.9% reduction in the MTB group. The between-group treatment difference was statistically significant (p<0.0001) with the ZBPT group demonstrating greater plaque removal [Figure 1]. Shows a graphical representation of the overall result along with the results for the sub regions examined. The percentage plaque reduction in the various subregions within the ZBPT group ranged from 47% to 61% and within the MTBPT group ranged from 7% to 45%. The ZBPT group demonstrated statistically significant greater plaque reduction in all subregions (p<0.0001).

Table 2: Baseline Plaque Results: Pre- and Post-brushing

Figure 1: Percent plaque reduction from pre-brushing to post-brushing at the Baseline visit for the overall dentition and various subregions. The between-group differences are statistically significant for the overall score and for all subregions. ZBPT = ZERObrush power toothbrush, MTB = manual toothbrush.

A comparison of plaque scores at Baseline and Week 4 is presented in [Table 3]. Examining the within-group pre-brushing plaque scores showed that the ZBPT group returned at Week 4 with statistically significantly lower plaque scores than at baseline whereas there was no statistically significant reduction in the plaque scores in the MTB group. For pre-brushing scores, the ZBPT group showed a 0.39 reduction compared to a 0.07 score reduction in the MTB group. This between-group treatment difference was statistically significantly different (p=0.0243). Examining the post-brushing plaque scores showed that at both Baseline and Week 4 the ZBPT group has lower plaque levels than the MTB group, with the between group treatment difference being statistically significant (p=0.0002, p=0.0005; respectively).

Table 3: Plaque Score Changes from Baseline to Week 4

Changes in gingival bleeding and inflammation from Baseline to Week 4 are presented in [Table 4]. There was no statistically significant difference in the gingival bleeding or inflammation scores between the two groups at Baseline. However, at Week 4 both the bleeding and inflammation scores were trending downward in the ZBPT group but trending upward in the MTB group, indicating that the ZBPT group’s gingival health was improving while the MTB group’s gingival health was worsening. Examining the change in score from Baseline to Week 4 for both bleeding and inflammation showed the between-group treatment differences were statistically significant (p=0.0012, p<0.0001; respectively).

Table 4: Gingival Bleeding and Inflammation Changes from Baseline to Week 4

Changes in gingival recession from Baseline to Week 4 are presented in [Table 5]. Only the 57 subjects who had recession at either visit were included in the analysis (N=30 in the ZBPT group, N=27 in the MTB group). There was no statistically significant difference in the recession measures between the two groups at Baseline. Although the recession measures trended lower for both groups, the changes from Baseline were not statistically significant.

Table 5: Recession Changes from Baseline to Week 4

There were no adverse events reported in the study.

Discussion and Conclusions

ZBPT is a full-mouth power toothbrush with a custom-fit mouthpiece that removes dental plaque and debris from the surfaces of teeth. The ZBPT handle vibrates the mouthpiece, activating cleaning tips to gently scrub the tooth surfaces. Examinations of the single-brushing plaque removal results from this study indicate that use of the ZBPT resulted in a statistically significant superior level of plaque removal as compared to use of the MTB. Use of the ZBPT also resulted in less plaque remaining on the surfaces of the teeth after 4 weeks of use as compared to the MTB. Further, the study indicates that ZBPT use resulted in a more even level of plaque removal throughout the mouth than the use of the MTB. These results demonstrate a significant oral hygiene benefit to ZBPT users and are likely to be due to the customized fit of the mouthpiece and uniform surface coverage of the complete dentition during brushing.

For a novel toothbrush to be routinely used as part of daily oral hygiene, a high level of user acceptance is preferred. The results of the consumer research presented here show that the participants found the ZBPT to be desirable with 89% wanting to continue using it as it delivered a superior clean feeling. Users commented on how the custom-fit mouthpiece “hugs every tooth surface” providing “gentle gum care” and “confidence that every tooth is thoroughly cleaned every time”. Participants noted the “quick, thorough cleaning” made them less likely to skip brushing sessions.

Research shows that manual toothbrush users distribute brushing time unevenly across different areas of the mouth. People tend to spend more time brushing the buccal surfaces of the anterior teeth and less time on lingual surfaces, especially in posterior regions. This uneven brushing may lead to plaque accumulation on unbrushed surfaces with resulting higher levels of calculus formation and gingival inflammation. ZBPT brushes dental surfaces evenly by contacting all accessible surfaces at once. The ZBPT user no longer needs to be concerned about uniformly moving the toothbrush throughout the mouth. The results of this study, particularly as shown in [Figure 1], demonstrate that ZBPT use provides superior plaque removal in all sub regions of the dentition.

Dental professionals recommend brushing for 2 minutes twice a day, but MTB users often spend a minute or less per brushing. Assuming the average brusher has 28 teeth with 3 accessible brushing surfaces per tooth (facial, lingual, occlusal) and assuming the typical MTB brushes 3-4 surfaces at a time, a 60 second MTB brushing results in approximately 2-3 seconds of brushing spent on any given surface. During ZBPT use, each tooth surface receives 30 seconds of brushing. Reduced amount of time needed to brush one’s teeth and concurrent uniform dental plaque throughout the mouth can be strong motivators for regular oral hygiene.

This study showed that 4 weeks of ZBPT use provided superior bleeding and gingival inflammation reduction as compared to the MTB. As this was primarily a dental plaque reduction study and subjects were not selected based on these gingival health indices, the resulting subject scores were rather low at baseline. The reduction in bleeding and inflammation with the ZBPT is expected based on the reduction in plaque over the 4-week period. The increases in bleeding and inflammation within the MTB group suggest that the level of daily plaque removal with the MTB was insufficient to prevent a trend towards worsening gingival health.

The results of this study suggest that ZERO brush was well accepted by users and that the use of ZERO brush for 30 seconds provides superior removal of dental plaque and improvements in gingival health as compared to the use of a manual toothbrush for 60 seconds.

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