Introduction
Although attractiveness and acceptability of orthodontic appliances have been rated by adults for themselves and for adolescents, children and adolescents have not provided any substantial data. The objective of this study was to evaluate preferences and acceptability of orthodontic appliances in children and adolescents.
Methods
Images of orthodontic appliances previously captured and standardized were selected and incorporated into a computer-based survey. Additional images of shaped brackets and colored elastomeric ties, as well as discolored clear elastomeric ties, were captured and incorporated onto existing survey images with Photoshop (Adobe, San Jose, Calif). The survey displayed 12 orthodontic appliance variations to 139 children in 3 age groups: 9 to 11 years (n = 45), 12 to 14 years (n = 49), and 15 to 17 years (n = 45). The subjects rated each image for attractiveness and acceptability. All images were displayed and rated twice to assess rater reliability.
Results
Overall reliability ratings were r = 0.74 for attractiveness and k = 0.66 for acceptability. There were significant differences in bracket attractiveness and acceptability in each age group. The highest-rated appliances were clear aligners, twin brackets with colored ties, and shaped brackets with and without colored ties. Colored elastomeric ties improved attractiveness significantly over brackets without colored ties for children in the 12-to-14 year group. There was a tendency for older subjects to rate clear orthodontic appliances higher than did younger subjects. Ceramic brackets with discolored ties tended to be rated lower than ceramic brackets with new ties and scored lowest in acceptability and attractiveness in all age groups. Girls rated shaped brackets significantly higher than did boys.
Conclusions
Children’s preferences for orthodontic appliances differ by age and sex. Child and adolescent preferences differ from adult preferences.
Traditionally, the options for bracket style or appliance design were considerably limited for both the patient and the provider. Recently, the orthodontic market has experienced phenomenal growth in the development and production of orthodontic appliances that are designed to appeal to the patient consumer. A shifting paradigm toward dental esthetics, increased demand for orthodontic treatment, consumer-driven desire for esthetic treatment alternatives, and a competitive orthodontic industry and specialty have all contributed to the development and production of alternative orthodontic appliances and new bracket styles. Orthodontic patients and practitioners now have a variety of treatment options previously unavailable.
Orthodontic appliances have evolved according to public demand and available technology, with the underlying goal, in large part, to reduce the visibility of the appliances. With the development of successful direct bonding techniques, the use of custom-fitted bands was replaced by bondable brackets. Plastic and ceramic brackets were developed to provide a relatively clear and esthetic alternative to metal braces, but they also introduced greater complications with bonding and breakage, decreased treatment efficiency, and increased costs to the patient and the provider. Clear plastic tray aligners (eg, Invisalign, Align Technology, Santa Clara, Calif) and lingual braces were developed to provide even more invisible options for patients, but they have unique clinical obstacles and treatment limitations.
Some advances in appliance design, however, have moved against the trend for clear or invisible appliances. Elastomeric ligature ties, for the most part, have replaced steel ligature ties as a means of engaging archwires and introduced a variety of colors for patients to select. Companies such as WildSmiles (WildSmiles, Omaha, Neb) incorporated unique and eye-catching shapes into the base of traditional twin brackets, allowing patients to select from heart, star, soccer ball, football, or diamond shaped braces.
Just as each orthodontic appliance is unique in its esthetic qualities, each also has biomechanical benefits and potential limitations. For a practitioner providing bracket options for patients, selecting which bracket to offer becomes a function of both esthetics and functionality: what will be esthetically acceptable to the patient and clinically efficient for the doctor?
Few studies have investigated patients’ perceptions of appliance esthetics. Ziuchkovski et al evaluated the attractiveness and acceptability of traditional, ceramic, self-ligating, and lingual braces, as well as clear aligners for adults and their children. Rosvall et al evaluated an expanded set of bracket options and included an assessment of the value of esthetic appliances to consumers. Both studies found that attractiveness and acceptability varied significantly by appliance type: alternative appliances (lingual and clear aligners) >ceramic brackets >ceramic self-ligating brackets >all stainless steel twin and self-ligating brackets. They found no statistical significance between the various brands or styles in each category. These studies showed that adult consumers value less metal showing in their braces and were less willing to accept treatment with appliances they consider to be unesthetic.
Although these earlier studies gave a baseline of esthetic values for adult patients, they only indirectly answered how appliance esthetics apply to children. When adult subjects were asked whether the appliances would be acceptable for their child’s orthodontic treatment, Ziuchkovski et al found that all appliances that were rated less acceptable by adults were rated significantly higher in reference to their children. Rosvall et al, however, found no difference in how adult patients rated appliance acceptability for themselves or their children. In a survey of 160 orthodontically treated and untreated 27-year-old Swedish adults, 84% responded that they did, or would have been willing to, wear visible braces during adolescence if needed. When this same group was asked whether they would be willing to wear visible braces as adults, 77% of previously untreated subjects responded definitely or probably, compared with only 60% of those who had undergone previous orthodontic treatment. This suggested that children would be more willing to accept treatment with visible appliances than adults. At this point, no one has asked children and adolescents what they favor for orthodontic appliances and their esthetics. Such studies have been performed to evaluate adult preferences, but understanding the esthetic desires of the entire patient base requires further investigation of the preferences of children and adolescents.
The purpose of this study was to determine how children perceive the esthetic attractiveness and acceptability of a variety of orthodontic appliances. We evaluated the overall preferences of children and compared the interaction of preferences at different ages and between the sexes. This information will help practitioners recognize and meet the demands of young patients in their practices and provide a baseline of data to be used to assess future changes in patient preferences.
Material and methods
This research was designed as a computer-based survey, incorporating standardized digital images of orthodontic appliances to evaluate the esthetic preferences of children and adolescents. It was an extension of research projects previously performed by Ziuchkovski et al and Rosvall et al, and we used some of their previously acquired and standardized images. Research design and survey presentation was the same as used in these previous studies to maintain uniformity and allow a more accurate comparison of results. New variables studied in this project (colored elastomeric ties, shaped brackets, and discolored clear elastomeric ties) were digitally incorporated onto existing images acquired previously to limit confounding variables. A summary of the initial capture and manipulation of these is outlined below. For more details on the methods of image acquisition and standardization, readers are referred to the original articles.
A model was selected for placement and imaging of orthodontic appliances on the basis of good alignment of teeth and the absence of strong sex markers in the circum-oral region. Fabrication of a custom jig specific to the model’s dentition allowed for precise and reproducible placement of various bracket systems. Brackets were bonded from maxillary second molar to second molar, and a 14-mil Sentalloy nickel-titanium wire (GAC International, Bohemia, NY) was engaged in with AlastiK clear ligatures (3M Unitek, St Paul, Minn). An Essix (Raintree Essix, Metairie, La) appliance (clear tray) was fabricated and imaged to simulate clear tray alignment systems such as Invisalign.
Images were captured with a digital camera (D100, Nikon, Melville, NY) equipped with a Nikko 24 to 85-mm macro lens and Nikon SB-29s Macro Speedlight flash. Camera settings were manually set, and all in-camera image enhancement features were turned off. A custom jig was used for image acquisition to standardize the camera distance and angle. Lighting conditions were constant for all images acquired, and a GretagMacbeth Mini ColorChecker (X-Rite, Grand Rapids, Mich) was fastened to the jig to allow for standardization of images to the standard color reference patches.
Image incorporation and standardization was performed with Photoshop (version 7.0, Adobe, San Jose, Calif), and the inCamera plug-in software (version 4.0.1, Pictocolor Software, Burnsville, Minn). To limit confounding variables, a standard perioral smiling image of the model was captured and layered over intraoral appliance images. Appliance image position in reference to the smile layer was standardized by means of vertical and horizontal reference lines and verified by toggling between intraoral layers in Photoshop. Examples of several images acquired by this method are shown in Figure 1 .
Shaped brackets were supplied by WildSmiles and incorporated onto existing images. WildSmiles star and heart shaped brackets were selected to represent the bracket styles most appealing to male and female subjects. The brackets were mounted on a typodont model from maxillary canine to canine in the proper mesiodistal and incisal-gingival position. A 14-mil Sentalloy nickel-titanium wire was engaged with clear elastomeric ties. Images of the brackets were captured by using a digital camera (D60, Nikon) with standard flash and a Nikkor 18 to 55 mm lens. By using Photoshop Elements 7.0, WildSmiles brackets and ligature ties were individually cut and layered over an existing image at corresponding maxillary canine-to-canine brackets. Bracket brightness, contrast, hue, and saturation were adjusted to match adjacent brackets. Examples of the WildSmiles images are shown in Figure 2 .
Clear elastomeric ties on existing survey images were digitally enhanced to simulate colored elastomeric ties. Individual ties were traced and layered in Photoshop 7.0 on MicroArch (GAC International) and WildSmiles bracket images. The hue, saturation, and lightness of the elastomeric ties were adjusted to create accurate representations of red, dark red, green, orange, blue, light blue, pink, purple, violet, and gray ties. These colors were used to show the possible color options that patients could choose at appointments. Care was taken to record the level and degree of color enhancement to standardize colors between bracket images. Examples of colored elastomeric ties are displayed in Figure 3 .
Similar techniques were used to simulate the discoloration of clear elastomeric ties that typically occurs between appointments. Before image enhancement, digital photos were taken of several patients with ceramic brackets and clear elastomeric ties after 4 to 6 weeks of placement and used to reference the discoloration typically seen at adjustment appointments. By using Photoshop, clear elastomeric ties on Mystique brackets (GAC International) were then discolored (yellowed and darkened) according to actual patient images. An example of these brackets is given in Figure 4 .
Previous research showed no significant difference between how adult subjects rated 3 ceramic brackets: Mystique, Ice (Ormco, Orange, Calif), and Clarity (3M Unitek). Because Mystique had the highest average visual analog score (VAS) in previous research, it was selected to represent ceramic brackets in this survey. There was also no significant difference in previous studies between the control (representing lingual braces) and the Essix (representing Invisalign). Because it could be confusing for children to rate an orthodontic appliance that they could not see, we eliminated the image of lingual braces from this survey. Table I details the appliances and ligature tie combinations used in this study.
| Appliance/tie combination | Type of appliance |
|---|---|
| GAC MicroArch, clear ties | Standard twin stainless steel |
| GAC MicroArch, colored ties | Standard twin stainless steel |
| WildSmiles hearts, clear ties | Stainless steel shaped |
| WildSmiles hearts, colored ties | Stainless steel shaped |
| WildSmiles stars, clear ties | Stainless steel shaped |
| WildSmiles stars, colored ties | Stainless steel shaped |
| GAC In-Ovation R | Stainless steel self-ligating |
| Ormco Damon 3 | Hybrid self-ligating |
| GAC In-Ovation C | Ceramic self-ligating |
| GAC Mystique, clear ties | Ceramic |
| GAC Mystique, discolored ties | Ceramic |
| Essix (clear tray) | Clear tray aligner |
Acquired and standardized images were incorporated into a computer-based survey and administered to children and adolescents 9 to 17 years old. The survey was designed and prepared by using a numerical computing environment and programming language software (MATLAB R2008a, Mathworks, Natick, Mass). A customized mouse-operated graphic interface was developed that combined data collection and survey administration. Images were displayed on a laptop computer (Pavilion dv6000, Hewlett Packard, Palo Alto, Calif) with a 17-in monitor at a life-size ratio to allow a realistic assessment of bracket esthetics.
The study was approved by the institutional review board of The Ohio State University. The subjects were recruited in the College of Dentistry clinics. Eligibility to participate in the survey included any willing child 9 to 17 years old who had never undergone orthodontic treatment with brackets or aligners. All surveys were completed on a laptop computer in the consultation rooms of the orthodontic clinic. The computer survey included an introduction, demographic information, instructions, and image rating screens. Subjects navigated through the survey by clicking “next” and were prevented from proceeding if all questions were not completely answered.
A series of tutorial screens instructed subjects on how to complete the survey and gave examples of orthodontic appliances to be rated. The subjects were instructed on how to use the VAS on a sample survey question and could practice using the scale by clicking or dragging the VAS marker. As an example of colored elastomeric ties, the subjects were shown a full smiling image of MicroArch brackets with red ties, displayed over a series of 9 variously colored elastomeric ties on single brackets. The subjects were told that these images represented their ability to select various colored ties at each orthodontic visit. The subjects were also briefly introduced to clear tray aligners and shown an image of an Essix appliance. At the conclusion of the instructional pages, the subjects were presented a grid of all 12 appliance images and instructed to take a minute to look at all images before starting the survey. By doing so, the subjects could familiarize themselves with all appliances before rating the first image displayed.
The image-rating pages consisted of a VAS question and a yes-or-no acceptability question. The subjects were presented the image to be rated and were asked, “how good do you think these braces look?” Attractiveness was gauged by means of the VAS, a horizontal bar anchored by “really good” on 1 side and “really bad” on the other. A thin gray marker in the middle of the bar could be dragged to the desired spot along the scale, or the subject could simply click anywhere along the bar to move the marker to that point. The subjects were then asked the acceptability question, “if you were going to have braces, would you be willing to wear these?” All orthodontic appliance images were displayed in random order. After each image had been displayed and rated once, all images were randomly displayed again, and the same questions were asked to evaluate intrarater reliability.
The final survey page displayed a grid of all 12 appliance images. The subjects were asked, “if you were going to have braces, which appliance style would you prefer most? Click on the picture of your favorite style; then click on your second favorite, third, fourth, and fifth.” While seeing all appliance options, the subjects could then rank their 5 favorite brackets.
The sample size was based on a power analysis with results from previous studies. The results of this analysis showed that a sample of 45 subjects in each age group (9-11, 12-14, and 15-17 years) was needed to detect statistical significance with a power of 0.8 and an alpha of 0.05. This allowed pair-wise comparisons between the 3 groups and potentially detected differences as small as 12% on the VAS scale.
One hundred forty-one subjects attempted to take the survey. One subject chose not to complete it after starting, and another was unable to complete the survey without help from a family member. The remaining subjects (n = 139) are detailed by their demographic groupings in Table II .
