Development and Evaluation of a Mobile Oral Health Application for Preschoolers

Introduction

Dental caries, also known as cavities, is a multifactorial, biofilm-sucrose-dependent disease, characterized by the progressive destruction of the mineral structure of dental tissues, that can be controlled by restricting the consumption of sugars in the diet and mechanical rupture of the dental biofilm through oral hygiene. ¹ Dental caries comprises the most prevalent chronic disease in children worldwide and is considered a public health problem. ^2,3 In Latin American and Caribbean countries, more than half of the preschool children from 5 to 6 years of age are still affected by this disease. ² In Brazil, according to data from the last survey carried out in 2010 by the Ministry of Health, 53.4% of 5-year-old children exhibited tooth decay in 2.43 teeth on average, and, at that age, the cavity index was higher than in the other analyzed age groups. ⁴

Social, economic, and cultural characteristics are associated with the risk of dental caries. In Brazil, a polarizing tendency of the prevalence of this disease in low-income and low-education populations has been verified. ^5,6 Considering that the lack of knowledge about the causes associated with the development of caries is also pointed out as a risk factor, health education plays a fundamental role in the prevention of disease and is one of the strategies advocated by the Ministry of Health to promote oral health since childhood, especially in the preschool phase, which corresponds to the moment of habit formation. ⁷

Considering that educational health actions should follow the current trend of using learning resources that are close to the reality of the target public, new technologies can facilitate access to health information for the child population through mobile learning with the use of digital games in application format. ^8,9 These games, which include multimedia and interactivity resources, are already part of the daily life of children, considered digital natives, and can be an alternative to propagate oral health information. ^{9 –11} However, few games in application format, developed especially for the preschool public, are focused on oral health education. The available options are predominantly entertaining and minimally educational. ^12,13

Therefore, in an attempt to promote access to oral health information, focusing on the prevention of cavities during childhood through learning resources that are close to the reality experienced by children, the present study aimed at developing an educational game in application format, for mobile devices, with usability tested for preschoolers under 6 years of age.

Materials and Methods

The study comprised an analytical, transversal, observational, descriptive, and quantitative assessment. The first stage consisted of the selection of the target public and the choice of topics to be explored in the software application, according to the Basic Attention Guidelines of the Ministry of Health. ⁷ Next, the development (execution and complementation) of the application was carried out, from January to July 2017, by the staff of the Technological Innovation Laboratory of the Christus University Center (UniChristus), with the participation of a multidisciplinary team composed of professionals from the areas of computing, health, and pedagogy.

The study was approved by the Research Ethics Committee of the Christus University Center, according to the norms that regulate human research of the National Health Council of the Ministry of Health (Resolution N. 196 of October 10, 1996 and Resolution N. 251 of August 07, 1997), under Certificate of Presentation for Ethics Appreciation (CAAE) number 68216617.6.0000.5049.

The interactive children's book flux design methodology was used for the conception, ideation, and execution of the interfaces of the game. ¹⁴ A digital educational game, named “1, 2, 3 … Brush!,” was developed in the mobile app format. The game was directed toward preschool children from 3 to 5 years of age and addressed the following topics: dental caries, healthy diet, cariogenic diet, oral hygiene, bottle feeding, the relationship between deciduous and permanent teeth, and prejudicial habits related to malocclusion. ⁷ Two versions of the application were developed for the major existing mobile platforms: Android^™ and iOS^™.

The following stage of the study consisted in determining the sample for the usability test. During application development, it is recommended to perform usability tests to identify possible problems in the interaction between the user and the interface, before commercialization. ¹⁵ An application's usability can be assessed by harmonizing its primary attributes: the potential of the interface to be understood by the user (“effectiveness”), by way of easy navigation (“efficiency”), that is user friendly (“satisfaction”). ¹⁶

To calculate the sample size, it was estimated that 90% of children would consider the application as usable. ¹⁷ Considering an infinite population with a power of 90% and a level of significance of 95%, an extrapolated N of 43 sample units was reached. The calculation was performed using the Epi Info ^™ software for Windows, version 7.2 (Centers for Disease Control and Prevention [CDC], Atlanta). The sample was randomly composed of preschool students from a public school of the municipal education network of Fortaleza-CE, Brazil, through a random lottery executed using the random.org website. The students of the Tertuliano Cambraia Municipal School who studied in the afternoon, which pertained to the analyzed age group (from 3 to 5 years) until the final date of the tests, were included in the lottery. The exclusion criteria comprised neurological conditions that interfered with the use of software applications and the absence of the children's compliance.

Thus, the composite sample for the study included twelve 3-year-olds, thirteen 4-year-olds, and eighteen 5-year-olds, totaling the 43 calculated sample units. Only one 3-year-old child did not want to participate in the test and was replaced by the next child in the lottery. The participation of the children was voluntary and required the authorization of their respective guardians through the signing of a Term of Free and Informed Consent.

The next step of the study consisted in conducting the usability test to evaluate the attributes of effectiveness, efficiency, and satisfaction in the use of the application regarding its four segments: Home Screen, Character Selection Screen, Application Exploration Screens (Story Menu), and the Proposed Activity Screens (Game Menu). In the efficiency evaluation, the children's performance was also analyzed in three activities proposed in the Game Menu, which addressed healthy diets (to identify cariogenic and noncariogenic foods) and oral hygiene habits (need for dental brushing after meals and before bedtime). The performance was analyzed according to the number of attempts required for each child to complete the activities.

Only one evaluator conducted all of the tests to avoid possible biases. The assays were applied in the library at the very school where the children study, given that it is a quiet environment, with minimal external stimuli that could interfere with the user's application experience. Images of the home screen of the application and a child executing the usability test are shown in Figures 1 and 2.

OPEN IN VIEWER

Fig. 1.

Home screen of the application.

OPEN IN VIEWER

Fig. 2.

Child executing the usability test.

Observation and interview surveying comprised the used techniques to evaluate effectiveness/efficiency and satisfaction, respectively, since these methods are used in usability tests with children who have not yet mastered the written language. ^18,19 The measuring mechanism applied to assess effectiveness and efficiency was the User's Success Rate, expressed as a percentage and calculated using specific equations, ^17,19 which consists of the sum of tasks performed correctly during the use of the application (such as selecting a menu or dragging objects). A task that was concluded successfully (“Yes”) equaled 100%; tasks completed with difficulty (“Partial”) represented 50% of success, and uncompleted tasks (“No”) corresponded to 0%. ^15,16 To measure satisfaction, a structured script form that had already been validated in the literature was used and it evaluated the following aspects: fun, ease of use of the application, user affinity with the character, interest of the user to repeat the user experience, and interest of the user to use the application at home. ^{18 –20}

After concluding the test phase, a sociodemographic questionnaire was applied to the child's respective guardian, in which the family income, the experience regarding the use of mobile devices by the child, and the purpose of their use were discussed.

The data collected in the assessments were analyzed by Fisher's exact test and the chi-square test, with a 95% confidence interval, using the SPSS^® software, version 20.0. (IBM Corp. Released 2011. IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp.).

Results

The results obtained in the usability test regarding the effectiveness and efficiency of the application are described below in relation to the total number of children in the study (N = 43) and by age group (Tables 1 and 2). Accordingly, the results concerning the satisfaction assessment are shown in Table 3. The p > 0.05 demonstrates that there was no statistical difference between the groups due to the high number of successfully executed tasks by the children during the usability test.

Regarding the performance in the three evaluated activities proposed in the Game Menu, the percentages of children of 3, 4, and 5 years of age, who selected all of the healthy foods on the first attempt in the game “Put the healthy food into the mouth,” were 25%, 76.9%, and 44.4%, respectively. In the postmeal oral hygiene game (“I just ate. What should I do?”), the percentages of the 3, 4, and 5 year olds that solved the activity on the first attempt were 91.6%, 76.9%, and 66.6%, respectively. In the game addressing the need for dental brushing before bedtime (“What to do before bedtime?”), the respective percentages of the 3, 4, and 5-year-old children that executed the activity on the first attempt were 91.6%, 76.9%, and 77.7%.

In the effectiveness and efficiency assessments of the Proposed Activity screens, the evaluated elements “The child did not have problems in solving the activities proposed in the application” and “The child managed to put the healthy food into the character's mouth” displayed different patterns of response compared to the other elements (p < 0.05), given that significant “Partial” and “No” results were observed in the 5-year-old children.

According to the data obtained from the sociodemographic questionnaire, 55.8% and 41.8% of the children had family incomes that were equal to or less than one minimum wage, and most of the children in the sample already used mobile devices (86%). Statistical analysis using Fisher's exact test and the chi-square test showed that the results obtained in the usability assessments did not exhibit a significant relationship with the family income and the use of mobile devices (p > 0.05).

Discussion

Dental caries in childhood is still considered a public health problem and may have negative repercussions on phonation, chewing, swallowing, esthetics, and the self-esteem of children affected by this disease. ^2,21 In this sense, educational strategies for dietary guidance and instruction in oral hygiene are essential for the prevention of caries and should be introduced as early as possible, thus providing means to promote self-care. ²² These actions must respect the cognitive characteristics of childhood, as well as prioritize playfulness as a way of arousing interest and motivation. ²³

The current model of health education, characterized as an active process of knowledge construction, has sought to use more dynamic approaches with resources that are closer to reality experienced by individuals. ²⁴ Few educational oral health applications, directed at preschoolers, are available. This makes the comparison between studies limited, given that most of the softwares that address the issue are aimed at primary school children. ⁹ The diversity of usability testing methodologies also hinders this comparison. ¹⁸ Educational strategies in oral health for children may follow this trend, using learning resources such as digital games. ⁹ Based on this, the game, developed in the present study, was designed to convey oral health information in a playful manner using mobile devices, which already constitute as tools in the daily life of children. ^10,11

Given that in the age group of the application's target public, most of the children are not yet literate, which could generate difficulty in understanding more complex interfaces, a gamified model (elaborated with elements of game mechanics) was employed, using animation and audio resources. The techniques selected for the usability tests in the present study are commonly used with children who have not yet mastered the written language. ^18,19,25

Usability tests with children present the following limitations that should be considered: the children's attention span, their motivation to please adults, the ability to adapt to new situations, possible difficulty in verbalizing their opinions, and their ability regarding abstract thinking and understanding of the assessed concepts. ^25,26 In view of the mentioned limitations, usability tests with children are generally performed with the use of more than one technique. ¹⁹ Thus, in the present study, the evaluation of the application's usability was conducted using two methods: observation and satisfaction interview surveying. ^{18 –20}

After assessing the effectiveness and efficiency of the Home, Character Selection, Application Exploration (Story Menu), and the Proposed Activity Screens, it was verified that the children understood the objectives of the interfaces, performing the tasks needed to navigate (such as accessing the start menu, selecting the desired character, brushing the character's teeth, and dragging objects) in all segments of the application, even if at some point they required assistance from the evaluator.

Thus, in the effectiveness and efficiency evaluations, the software application obtained satisfactory results, given that in usability tests the value of the success rate of these attributes usually remains around 50% since the user often makes mistakes the first time he/she uses an application. ¹⁷ The satisfaction assessment was also considerably positive, demonstrating the children's wide acceptance of the application.

The differences observed in the efficiency evaluation possibly occurred due to the inherent characteristics of the children participating in the study. Three year olds naturally require navigation assistance, even with applications developed according to the cognitive aspects of that age. ²⁷ The 5-year-old children obtained a lower efficiency performance possibly because they tend to act more untimely, which can be expected due to the leap that occurs in language development between 5 and 7 years of age (speech planner function), leading to difficulty in the coordination between thought and action. ²⁸

The activity in which the children displayed the most significant difficulty in all of the groups was the “Put the healthy food into the mouth” exercise. According to the obtained results, this was the game where the largest number of children required two or more attempts to complete the activity. This effect was observed not to be due to navigability (since the children were able to carry out the task of dragging objects), but because of the difficulty in differentiating healthy foods from cariogenic ones.

The choice of sweet foods by children may be related to the dietary habits of their families. The data obtained through the sociodemographic questionnaires revealed that almost all of the participants in the study come from families with incomes that are equal to or less than a minimum wage. Some studies correlate the prevalence of cavities in low-income communities to more substantial consumption of foods rich in sugar. ^3,29

Few educational oral health applications directed to the preschool public are available, which makes the comparison between studies limited, given that most of the softwares that address the issue are aimed at primary school children. ⁹ The diversity of usability testing methodologies also hinders this comparison. ¹⁸

During the usability test, the need to improve some of the screens to enhance the interaction between the users and the interface was verified. In the Story Menu, the home screen will be modified in order for the character to appear in the living room, with new audio: “Hello! Let's learn how to care for our teeth. Click the arrow below and let's go! 1, 2, 3 … Brush!.” Another alteration to be made will be on the flossing screen so that the floss always appears next to the bathroom sink. The dental floss animation will be replaced with an interactive activity, in which the child can use the floss to assist in the oral hygiene of the character. Finally, in the Game Menu, explanatory audio will be inserted at the end of the “Put the healthy food into the mouth” game, since it was the exercise in which the children exhibited the most difficulty, to emphasize the relationship between foods rich in sugar and dental caries.

Conclusions

According to the objectives of the present study, an educational game was developed, in an application format for mobile devices, with usability for preschoolers between 3 and 5 years of age, given that it obtained excellent results regarding the three evaluated aspects (effectiveness, efficiency, and satisfaction). However, future studies are necessary to verify the efficacy of the developed interface in the context of the children's learning process in health and the promotion of habits related to healthy diets and oral hygiene for the general preschool public.