Comparison of the accuracy of bracket axial positioning with and without radiographic support and according to practitioner experience: A three-dimensional study.

INTRODUCTION: Accurate bracket positioning remains challenging. To avoid angulation errors, some recommend examining the panoramic radiograph during bonding. However, it can cause distortions. Cone-beam computed tomography (CBCT) provides a more precise panoramic reconstruction but with higher radiation doses. The main objective of this study is to compare the accuracy of axial positioning between direct bonding without radiography, with conventional panoramic radiograph, and with panoramic reconstruction from CBCT. The secondary objectives are to evaluate positioning accuracy of each tooth and to assess the influence of practitioner level of experience. METHODS: Thirty practitioners, divided into two groups based on their experience performed direct bonding on a model thrice: without radiography, then with the conventional panoramic radiograph, then with the panoramic reconstruction from CBCT. Models were scanned, and angulation errors were measured using OrthoAnalyzer. Values were compared using the Friedman's test followed by the Bonferroni correction for multiple comparisons (P-value = 0.05). RESULTS: For the low level of experience group, angulation errors were significantly greater than the accepted limit without radiographic reference, and significantly lower with CBCT reconstruction. For the high level of experience group, angulation errors were significantly lower than the accepted limit for the three bonding methods. For every tooth, using the panoramic reconstruction from CBCT as a reference, was the most accurate method, regardless of the level of experience. More experienced practitioners made fewer errors for the three methods. CONCLUSIONS: Panoramic reconstruction from CBCT is the most accurate method to limit angulation errors during direct bonding. Conventional panoramic radiography remains a reliable tool if used with caution. Bonding without any radiographic reference should be avoided especially for less experienced practitioners.

Influence of orthodontic bracket prescription on smile attractiveness in patients with different sagittal skeletal patterns: A 3-dimensional cross-sectional study.

INTRODUCTION: The objective of this study was to evaluate the influence of orthodontic bracket prescription on smile attractiveness. METHODS: Three women were chosen according to their sagittal skeletal pattern: skeletal Class I, II, or III malocclusion. For each, 3 smiling pictures were taken in frontal, oblique, and lateral views. The maxillary arch was then scanned, and a 3-dimensional digital model was constructed on the OrthoAnalyzer software. The information of 3 orthodontic prescriptions, namely Roth, MBT, and Ricketts, was simulated after the virtual placement of orthodontic brackets on 10 maxillary teeth. The simulations were then superimposed on the smile photographs in the 3 views, creating a total of 27 images. Groups of orthodontists, dentists, and laypeople rated the attractiveness of each smile using the visual analog scale. RESULTS: This study included 167 evaluators: 54 orthodontists, 54 dentists, and 59 laypersons. In terms of orthodontic prescription, MBT esthetic scores were 4% lower than Roth scores (P <0.001), and Ricketts scores were 13.6% lower than Roth scores (P <0.001). In terms of skeletal pattern, Class II and III scores were 15.0% and 16.4% lower than Class I scores, respectively (P <0.001). Regarding the smiling view, oblique view scores were 3.1% lower than frontal view scores (P = 0.031), whereas lateral view scores were 8.4% lower than frontal view scores (P <0.001). In contrast to gender and age, the specialty of the evaluators significantly affected the esthetic rating of the smiles. CONCLUSIONS: The attractiveness of a smile is affected by the prescription of the brackets. The Roth prescription tends to obtain the most favorable esthetic scores, especially in sagittal smiling images. Profile smiles with excessively proclined incisors are considered unattractive. Different views of the same smile do not get similar esthetic scores because sagittal views are rated the most severely.

Comparison of the accuracy of bracket positioning between direct and digital indirect bonding techniques in the maxillary arch: a three-dimensional study.

BACKGROUND/OBJECTIVES: When the indirect bonding technique was developed in 1972 by Silverman and Cohen, many authors wondered whether this technique would improve bracket positioning accuracy compared to the direct bonding technique. Studies have found little to no difference between them regarding positioning accuracy. Recently, technological advances have improved the indirect method by allowing the user to position the brackets virtually using software applications such as OrthoAnalyzer™. To the best of our knowledge, no studies have compared direct positioning to this new digital indirect technique. Thus, the aim of this study was to compare the accuracy of placement between the two techniques in the maxillary arch using two different bracket types: conventional twin brackets and self-ligating brackets. A secondary objective was to evaluate whether bracket type affected positioning accuracy. METHODS: A maxillary arch of a patient was scanned by digital impression. Forty resin duplicates of this model were printed and then mounted on a mannequin head, on which 20 practitioners performed direct bonding using the aforementioned brackets. Later on, they performed a virtual indirect bonding of the same case virtually, with the digital impression superimposed to the patient's CBCT (cone-beam computed tomography). Afterwards, the direct bonded models were unmounted, scanned, and then superimposed to the indirect models. Differences in height, angulation and mesio-distal position of the brackets were evaluated. RESULTS: Regarding height, the differences between direct and indirect methods were not significant. Height difference was significantly greater for self-ligating brackets compared to conventional brackets. Regarding mesio-distal positioning, significant differences were noted for teeth 13 and 15 with self-ligating brackets (p-value = 0.019 and p-value = 0.043, respectively). The deviation was also greater for these brackets. Regarding angulation, the difference was significant on tooth 12 when using conventional brackets (p-value = 0.04) and on 12 and 22 when using self-ligating brackets (p-value = 0.09). CONCLUSION/IMPLICATIONS: There were no major significant differences between direct and indirect bonding. Differences were significant only on the laterals for of angulation, and on teeth 13 and 15 for mesio-distal centering. The bracket type seems to influence positioning accuracy, since self-ligating brackets had a larger deviation range than conventional brackets.