Dental prophylaxis in children and adolescents with gamification

>> Digital games already exist that support and motivate children in optimizing their dental care and oral health. These entertaining toothbrushing games fall under the umbrella term gamification (Lampert et al. 2009: 1). The goal of these games is to increase users' motivation to complete daily tasks, such as brushing their teeth, through playful approaches and reward systems (Stieglitz 2017: 4).
Given the fact that communication devices are part of the everyday life of children and adolescents (bitkom 2014: 4) and, for example, 94% of 6- to 18-year-olds own a smartphone and 61% most frequently use applications with their mobile phones (Berg 2017), it is obvious to also use this methodology in oral hygiene.
Regarding the effectiveness of these digital games for dental prophylaxis, there are only few empirical results available in Germany as of April 2020. Wölber summarizes the key studies, but only addresses two projects conducted in German-speaking countries that tested the effectiveness of application-based digital motivational aids. Further studies on an application (app) were conducted in Atlanta and London. Three studies were found in the area of non-game-based motivational aids (Wölber 2017: 26). The study by Höfer et al., which examined the effect of a toothbrushing app on children, is the only study that shares similarities with this empirical study. In 2017, Höfer's research group tested the effectiveness of the toothbrushing app "Rainbow" on 49 five- and six-year-old children. The study lasted a total of twelve weeks. During this time, the subjects' plaque and gingivitis (values for gum inflammation) levels were recorded using oral hygiene indices. The assessment was conducted at baseline and after six and twelve weeks. The study showed that both the extent of plaque and gingivitis in preschool children could be reduced (Höfer et al. 2017: 78).

Goal
Due to the limited results on the effectiveness of gamification approaches in toothbrushing, the importance of daily oral hygiene, and the technological advances in toothbrushing games, this study focuses on oral hygiene in children and adolescents. The aim of this study is to evaluate the effectiveness of the game "ZahnHelden" on oral hygiene and to test whether the toothbrushing app leads to an improvement in plaque levels.
The study aims to answer the research question “How does the application-supported toothbrushing game ‘ZahnHelden’ influence the toothbrushing behavior of children and adolescents?”
methodology
Study procedure
The study was conducted at a dental practice in Essen between September 7 and October 23, 2017. Children and adolescents between the ages of 6 and 17 visited the dental practice twice for the study. There were an average of seven days between the two appointments. On both visits, the participants brushed their teeth independently in the practice using disposable toothbrushes with integrated toothpaste. In the first session, they performed their oral hygiene without the "ZahnHelden" toothbrushing app, and in the second session, they used it with the app.
The app was developed by goDentis – Gesellschaft für Innovation in der Zahnheilkunde mbH and released on March 8, 2016. The application is available free of charge in both the Apple Store and the Google Play Store and is therefore compatible with all Apple and Android devices. The app is available in German. The digital game is designed to be child-friendly and is recommended for children aged 5 and over. Children and teenagers can use the app while brushing their teeth. The app is positioned at face height. The Optical Flow camera function, which records brushing movements and their position from the mobile phone or tablet camera, ensures brushing control. If the position of the toothbrush changes, the app recognizes that the child is brushing at that moment. Brushing instructions are given while the app is used. The app specifies how long each area of the mouth should be brushed. Users receive immediate feedback on their brushing performance in the form of motivational sayings. After brushing your teeth several times with the help of the app, sounds are unlocked with which you can compose a song.
The tablet containing the application was held at face level by the dental prophylaxis assistant (DPA) during the test. In both sessions, after the children and adolescents had completed their oral hygiene routine, their teeth were stained with a plaque stain and the Quigley and Hein Plaque Index (QHI) was determined.
Plaque levels were documented by hand. Following the second session, a short oral survey was conducted in which the children and adolescents answered questions about their motivation and use of the app while brushing their teeth.

sample
Participants were actively and personally approached in the practice during their dental appointment in September and October 2017. The plan was to recruit 30 participants for this study. Participants were divided into two target groups based on their age: children between the ages of 6 and 11, and adolescents between the ages of 12 and 17. This classification was made because the participants were at different stages of development, during which their motivation to pay attention to oral hygiene can vary (Staehle et al. 1996: 17).
Dental key figure
The Quigley and Hein index (QHI) was used as a statistical dental indicator, which was calculated using an indicator liquid.
ity illustrates the extent of bacterial deposits, also called plaque, on a tooth surface (Hellwege 2003: 47).
For plaque visualization, the Mira-2-Ton plaque test from Hager and Werken was used. This test colors newly formed plaque red and older plaque blue (Hellwege 2003: 44). However, the focus of this study was on whether and to what extent the vestibular surface of the tooth contains bacterial plaque.
Plaque deposition was assessed using a scale with six grades:
2.4 Structure of the questionnaire
The survey was designed as an oral, structured interview with written questions and standardized response options. It contained a total of nine questions. Both the questions and the response options were formulated in simple, child-friendly language. The questionnaire was divided into the following four sections:
1. The first part of the questionnaire collected the participants' personal data. This included questions about age, gender, and daily toothbrushing frequency.
2. The second part focused on information about motivation via the app. The questions were aimed at the following: "Is brushing your teeth more, the same, or less fun with this app than without the app?" "Would you look forward to the next brushing and the new sound, or does it not matter to you?"
3. In the third part, questions were asked about the app's use and whether respondents would recommend it to others. These questions included: "How did you find brushing your teeth with the app? Easy or difficult?" "Would you recommend brushing with the app to your friends?" "Do you think you will continue brushing with the app?"
4. In the fourth and final part, the plaque values of the first and second sessions were documented.

The analyses were conducted using SPSS version 21. Descriptive analyses (frequency distributions, means, and standard deviations) were primarily performed. Valid cases were used as the basis for the analyses. Mean comparisons were performed using t-tests, and the Pearson correlation coefficient was analyzed. A value of α=5% was used as the significance level for each statistical test.
Hypotheses
At the beginning of the study, hypotheses were formulated that will be explored through this empirical study. These hypotheses are:
• Participants find brushing their teeth more enjoyable with the app than without it.
• The reward function of the application motivates the children's age group and the male participants more than the adolescents' age group and the female participants.
• In all subjects, the plaque volume decreased with the use of the app.

It is assumed that children and adolescents enjoy brushing their teeth more with the app than without it. Furthermore, it is assumed that children and male participants find the reward function more motivating than adolescents and female participants. This assumption is based on the fact that boys play digital games more often than girls, are more interested in technology, and are more ambitious (German Employees' Health Insurance), and the game was designed specifically for children with a child-friendly design. A similar study by Höfer et al. showed that the toothbrushing app "Rainbow" had a positive influence on toothbrushing behavior in five- and six-year-old children. Lower plaque levels were observed after the app was used (Höfer et al. 2017: 78). For this reason, it is also assumed for this study that the extent of plaque in participants decreases with the use of the "ZahnHelden" app.
Results
sample
The following provides an overview of the results of this study. These are divided into four sections. First, the interview responses, which are based on the children's and adolescents' self-assessment of the app, are presented. Next, the results of the measured plaque values from the two different examination sessions are summarized.
Of the 32 children and adolescents surveyed, 24 children and adolescents (n=24) participated in the study. This resulted in a participation rate of 75%. The average age of the participants was 11.13 years (min. 6; max. 17). In terms of age groups, the participants were divided into 11 children (46% of the participants) and 13 adolescents (54% of the participants). The female proportion was 42%, and the male proportion was 58%.

Results of the interview
As an initial question, participants were asked about their daily brushing frequency. Most participants reported brushing their teeth twice a day (831, 313).
The oral interviews revealed that none of the children or adolescents had previously used a toothbrushing app. The interviews also revealed that the participants found it fun while using the "ZahnHelden" app, as no one stated that brushing their teeth with the app was not fun. This was particularly evident in the children's age group and the male participants. The reward function was perceived as motivating overall, especially among the adolescent group (641 participants) and the male group (571 participants).
When asked about the difficulty of using the app, most participants stated that they found it easy to use. Almost 80% of participants would recommend the app to their friends, and more than half would continue to use the app for their home oral hygiene routine.

Plaque value results
The fourth part of the questionnaire involved documenting plaque levels from the two examination appointments. To determine whether using the "ZahnHelden" app led to improved plaque levels, or whether differences between children and adolescents, or between boys and girls, were observed, the index values were subsequently examined.
Figure 1 shows the two mean values of the measured values without using the app (QHI I) and with using the app (QHI II). The lower the QHI, the less plaque is present on the tooth surfaces.
The values show that female participants brushed their teeth best, but the greatest improvement was seen in male participants. The value for the first session was 1.718. In the subsequent session, the value improved by 0.393. The independent samples t-test highlights that the gender of the participants had a significant influence on the absolute difference between the trials (p=0.035).
However, significant improvements can also be seen in the children's category. Here, the mean of the QHI I is 1.71. The mean of the QHI II is 1.375. Here, the difference is 0.335. However, the analysis of the Pearson correlation coefficients does not allow any conclusions to be drawn regarding the influence of age on the test results, as the null hypothesis cannot be rejected at the significance level of α=5%.
When comparing the plaque mean values of the two sessions, a paired sample t-test showed that there was a highly significant improvement (p=0.002).
In summary, the results reflect a positive influence of the "ZahnHelden" app on the brushing behavior of children and adolescents aged 6 to 17 years. Using the game while brushing resulted in a statistically significant improvement in plaque removal from the vestibular smooth surfaces of the teeth. The greatest improvement in plaque levels, increased motivation during the game, and the greatest sense of enjoyment were observed particularly in the children's age group and the male group of participants.
discussion
The results are discussed below in relation to the hypotheses put forward.
The first hypothesis, that children and adolescents enjoy brushing their teeth more with the app than without it, was confirmed by the interviews. However, differences between the gender and age of the test subjects were evident. Significantly more children than adolescents stated that they enjoyed brushing their teeth more with the app than without it. Even during the test subject recruitment phase, it became clear that many older patients declined to participate in the study because they found the toothbrushing game too childish. The "ZahnHelden" app is fundamentally intended for younger users aged five and up. Therefore, special attention was paid to a child-friendly design during development.
Additionally, more boys (70% of boys) than girls (30% of girls) reported enjoying the app more. A study by DAK Gesundheit and the German Center for Addiction Inquiries found that gaming is the most popular online activity among boys (German Employees' Health Insurance). This study suggests that the enthusiasm and enjoyment of the game can be attributed to this.
The assumption that children and male participants are more motivated by the reward function than adolescents and female participants could only be partially confirmed. Before the study began, it was assumed that adolescents would consider the toothbrushing game "ZahnHelden" to be too childish and would show less interest in using it. However, more adolescents (571 participants) than children (431 participants) expressed enthusiasm for the reward function. This could be explained by the fact that the game and its reward function are easier for adolescents to understand. The interviews also revealed that the reward function motivates male participants more than female participants. One possible explanation for this could be the increased enthusiasm for technology and the pronounced ambition of boys (Wensierski 2015: 374).
The hypothesis that plaque levels would decrease in all participants with the use of the "ZahnHelden" app could not be fully confirmed. Not all participants showed improvement, but reduced plaque levels were observed in all categories (children, adolescents, girls, and boys). The Quigley and Hein indices from the two sessions showed a highly significant improvement in plaque levels (p=0.002) with the addition of the app.
The results of this study cannot be generalized due to the small number of participants. More studies need to be conducted in more cities. Home use and long-term effectiveness should also be investigated. This could be achieved by later monitoring whether the participants continued to use the "ZahnHelden" app, as stated in the interviews, and whether plaque levels have not changed after a longer period of time following the study. Bias also needs to be addressed. The improvement in plaque levels could also have been caused by inclusion in the study, as the children and adolescents knew that their brushing scores from the two measurements would be compared.
The results show that digital toothbrushing games can be used as a training and motivational tool to improve oral hygiene. Interview responses revealed that none of the participants had previously been familiar with or used an app of this type. To raise awareness of toothbrushing apps, they could be integrated into dental visits by having the dental assistant or dentist draw children's attention to the games. By testing them in person, children can become familiar with these types of apps, allowing them to use them at home and even become interested in using them.
The "ZahnHelden" toothbrushing app is therefore a useful addition to the hygiene routine, optimizing the fun, motivation, and effectiveness of toothbrushing. However, it is not a replacement for existing preventative measures, such as a visit to the dentist. Toothbrushing games can be integrated into the daily care routine and thus improve the overall quality of oral hygiene through the motivating gamification approach.
Conclusion
This study investigated and addressed the research question "How does the app-based toothbrushing game 'ZahnHelden' influence the toothbrushing behavior of children and adolescents?" To this end, the effectiveness of the "ZahnHelden" app was examined in an experimental research study.
The results showed that the toothbrushing app had a positive effect on the participants during brushing, as reduced plaque levels were recorded on the vestibular tooth surfaces of most participants. The study was able to show that the improvement in plaque levels through the use of the app was statistically significant. Furthermore, the oral interviews showed that the app motivated the participants through its feedback and reward functions. The participants also stated that brushing their teeth with the app was just as much or even more fun. The greatest improvement in plaque removal and the greatest motivation were observed in male participants and children aged 6 to 11. This shows that there is a difference both between the age group of children and adolescents and between male and female participants.
The app-based toothbrushing game "ZahnHelden" can therefore be used as a training and motivational aid for both children and adolescents. It supports caries prevention by teaching users a systematic brushing routine, getting them accustomed to daily brushing, and developing motivation and enjoyment for brushing.
However, it was also found that none of the participants had previously known about or used a toothbrushing app. In practice, this suggests that toothbrushing apps should be made more widely known.
Just like this study, other studies cannot provide information on the long-term effectiveness of toothbrushing apps. This is where further studies should begin to investigate the long-term effects of the gamification approach in dentistry.