# Prototype of Augmented Reality Technology for Orthodontic Bracket Positioning: An In Vivo Study
###### Abstract  
To improve the accuracy of bracket placement in vivo, a protocol and device were introduced, which consisted of operative procedures for accurate control, a computer-aided design, and an augmented reality-assisted bracket navigation system. The present study evaluated the accuracy of this protocol. Methods: Thirty-one incisor teeth were tested from four participators. The teeth were bonded by novice and expert orthodontists. Compared with the control group by Boone gauge and the experiment group by augmented reality-assisted bracket navigation system, our study used for brackets measurement. To evaluate the accuracy, deviations of positions for bracket placement were measured. Results: The augmented reality-assisted bracket navigation system and control group were used in the same 31 cases. The priority of bonding brackets between control group or experiment group was decided by tossing coins, and then the teeth were debonded and the other technique was used. The medium vertical (incisogingival) position deviation in the control and AR groups by the novice orthodontist was 0.90 \(\pm\) 0.06 mm and 0.51 \(\pm\) 0.24 mm, respectively (_p_ < 0.05), and by the expert orthodontist was 0.40 \(\pm\) 0.29 mm and 0.29 \(\pm\) 0.08 mm, respectively (_p_ < 0.05). No significant changes in the horizontal position deviation were noted regardless of the orthodontist experience or use of the augmented reality-assisted bracket navigation system. Conclusion: The augmented reality-assisted bracket navigation system increased the accuracy rate by the expert orthodontist in the incisogingival direction and helped the novice orthodontist guide the bracket position within an acceptable clinical error of approximately 0.5 mm. augmented reality; orthodontic; bracket navigation system; bracket positioning +
Footnote †: journal: _Sci._  
Footnote †: journal: _Sci. in front of their eyes, which improved their wire construction efficiency and lowered errors [2; 3]. Gradually, AR expanded to various fields, including gaming, service, factory assembly, and medical industries. In the field of oral medicine, AR is also used in oral maxillofacial surgeries, dental implant [4; 5], and oral education [6]. In addition, AR can promote the development of orthodontics [3]. The problem of accurate orthodontic bracket positioning is being discussed for many decades now. In 1972, [PERSON] devised the straight wire (preadjusted) appliance, which the technique reduces a part of wire bending [7; 8; 9]. The concept of straight wire appliance is each bracket has built-in specific torque, tip, in/out, and proper offset to achieve proper alignment of the center of the slot and to allow teeth to properly settle in the ideal final positions. The most important thing when using the straight wire appliance is bracket positions. However, inaccurate bracket positions can affect occlusal function and dental aesthetics, causing articulation disorders and grooved marginal ridges between teeth; inaccurate bracket positions can also increase the likelihood of food becoming lodged between teeth, which can inflame the gingiva, damage the alveolar bone, and lead to periodontal disease [10]. The problem of inaccurate bracket positions does not only occur because of orthodontics being performed by different clinical dentists. Even when the treatment is performed by the same dentist, bracket deviation of teeth in different quadrants is likely. Various factors can affect bracket positioning, including the clinical crown height, tooth morphology, abnormal incisor line, and occlusal interference. Therefore, making accurate orthodontic decisions is critical for clinical dentists. In the past, dentists could only rely on their experience and adjust the bracket positions until correct positioning was achieved.