Three-Dimensional Digital Superimposition of Orthodontic Bracket Position by Using a Computer-Aided Transfer Jig System: An Accuracy Analysis

Influence of 3D printing angles on the accuracy of indirect adhesion transfer models: an in vitro study

The aim of this study was to evaluate the effect of different Angle printing on the model on the printing platform and whether it affects the later transfer accuracy. Ten bracket transfer models were printed on the platform of the 3D printer in four ways: 0° without support rod, 0°, 45° and 90° with support rod. Transfer guide plates for transfer brackets were made using PVS. The linear and angular discrepancies were determined digitally by measuring six different dimensions. The best performance was achieved at 90° with a support bar, with mesiogingival wing center point gap and diogingival wing center point gap of 0.169 and 0.176, respectively (P < 0.05). The linear deviation of groups A and B in the vertical direction was highest (0.285 (P < 0.001) and 0.283 (P < 0.001), respectively) when the transfer guide plate was made by PVS for the transfer bracket, followed by the proximal and distal direction. The best performance was achieved in the Orovestibular. The printing angle of the 3D indirect bonding slot transfer model on the printing platform significantly impacts the transfer accuracy, with the accuracy of the 45° and 90° bracket models having the least impact. A minimum transfer error of 90° since 90° 3D printed bracket transfer models with support rods have the best reliability.

Simplified ABO-OGS orientation improves training of orthodontic bracket positioning for undergraduate dental students

BACKGROUND

Mastery of orthodontic bracket bonding is an essential component of the undergraduate orthodontic curriculum. Traditional bracket bonding training using simple plaster models has some shortcomings, including a disconnect from clinical practice and poor perception of the criteria and accuracy. This study aims to optimize the bracket bonding course by comparing the traditional teaching method with simplified American Board of Orthodontics Objective Grading System (ABO-OGS)-oriented training methods.

METHODS

Fourth-year dental students from Fujian Medical University, spanning the 2015 to 2017 cohorts, participated in the orthodontic bracket bonding course. Students from these three cohorts were trained using the traditional plaster model method, the digital 2D ABO-OGS-oriented method, and the typodont ABO-OGS-oriented method, respectively. After the course, students and teachers completed a six-level Likert scale questionnaire to evaluate the teaching objectives, methods, and efficacy.

RESULTS

Both teachers and students agreed that the traditional bracket bonding training and the simplified ABO-OGS-oriented bracket bonding training were effective, with most students mastering the bracket bonding procedure. The simplified ABO-OGS-oriented bracket bonding was perceived as more novel and engaging compared to the traditional method (P < 0.05). However, the digital 2D ABO-OGS method was significantly less effective than the other two methods (P < 0.05). Instructors rated the typodont ABO-OGS-oriented training higher than the students did (P < 0.05).

CONCLUSION

Both the traditional and simplified ABO-OGS-oriented courses for bracket bonding yielded favorable results, with the simplified ABO-OGS approach being more engaging and innovative. The findings emphasize the critical role of hands-on practice in achieving optimal proficiency in bracket bonding techniques. A hybrid educational model that integrates digital 2D or 3D ABO-OGS-oriented training with offline practical sessions shows considerable potential for qualifying training and examination of orthodontic residency students.

Potential for bracket bonding errors based on tray accuracy and fit: Evaluation of 6 photopolymer resins for indirect bonding trays

INTRODUCTION

We assessed the accuracy and fit of 3-dimensional (3D)-printed indirect bonding (IDB) trays fabricated using various photopolymer resin materials.

METHODS

A maxillary plaster model and 60 plaster replicas were created. IDB trays with arbitrary bracket configurations were 3D-printed using 3 hard resins (Amber [AB], TC85DAC [TC], Orthoflex [OF]) and 3 soft resins (IBT [IT], IDB2 [ID], and MED625FLX [MD]). A reference plaster model with a computer-aided design-designed IDB tray attached with nonfunctional, arbitrary bracket configurations on the buccal surface serving as reference points for measurement was superimposed on scanned plaster replicas holding 3D-printed trays to assess transfer accuracy and clinically acceptable error. Printing accuracy was assessed by comparing computer-aided design trays to printed trays, and tray fit was measured by the gap volume between the tray and plaster replica using a Fit-Checker (GC Corp, Tokyo, Japan).

RESULTS

Six tray groups showed significant linear transfer errors, particularly in the vertical direction (0.15 mm [95% confidence interval {CI}, 0.10-1.15]; P = 0.004). The OF group exhibited the largest vertical error (0.27 mm [95% CI, 0.19-0.35]), whereas the ID group had the smallest (0.10 mm [95% CI, 0.06-0.14]). Angular errors did not exhibit significant differences across the groups. Linear precision error was the highest in OF, followed by ID, TC, and MD, then AB and IT (P <0.001). Of all tray groups, 90.1% and 68.8% met the clinically acceptable linear (<0.25 mm) and angular errors (1°).

CONCLUSIONS

Linear errors, particularly vertical errors, are more material-dependent than angular errors. Gap volume alone was not a reliable predictor of IDB tray accuracy. Therefore, material-specific designs are needed to control the optimal fit and facilitate precise bracket placement.

Direct versus fully digital indirect bracket bonding: a split-mouth randomized clinical trial on accuracy

OBJECTIVES

The primary aim is to assess differences in accuracy of orthodontic bracket positioning between fully digital indirect bracket bonding (IDB) and conventional direct bracket bonding (DBB). The secondary aims are to assess differences in bracket bonding failures, bracket repositioning need, clinician experience and patient satisfaction.

MATERIALS AND METHODS

This prospective study was designed as a split-mouth randomized clinical trial. In total, 35 patients were analyzed with a six month follow-up period. Translational and orientational deviations from the planned bracket position were determined. Clinician experience and patient satisfaction were evaluated by means of a survey.

RESULTS

The difference in translation was 0.34 mm (95% CI: 0.238-0.352, p = 0.017), the difference in orientation was 4.80˚ (95% CI: 3.858-5.727, p < 0.001), both in favour of IDB. IDB showed significantly more immediate (IDB: 3.9%, DBB: 0%) and late (IDB: 5.4%, DBB: 2.5%, p = 0.008) bonding failures. Clinicians and patients experienced a shorter clinical chair time with indirect bonding over direct bonding.

CONCLUSIONS

IDB bracket positioning leads to significant smaller translation and orientation deviations from digital IDB planning, than DBB bracket positioning. However, IDB leads to more immediate bonding failures than DBB. The majority of patients preferred IDB over DBB, due to a shorter clinical chair time.

CLINICAL RELEVANCE

This study adds to the knowledge of IDB in orthodontics and contributes to evidence on this technique. This evidence is applicable in everyday orthodontics, with respect to patient satisfaction and technical limits of IDB. The trial was registered in the Dutch Trial Register and the International Clinical Trials Registry Platform (ICTRP) of the World Health Organization (WHO), number NL9411.

Effect of fence tray matching care on excess adhesive and bracket placement accuracy for orthodontic bonding: an in vitro study

OBJECTIVE

This study aimed to evaluate the effect of fence tray matching care (FTMC) in bracket bonding by measuring excess adhesive, as well as linear and angular deviations, and by comparing it with the half-wrapped tray (HWT).

MATERIALS AND METHODS

An intraoral scanner was used to acquire data on the maxillary dental arch of a patient with periodontitis.Furthermore, 20 maxillary dental arch models were 3D printed. Using 3Shape, PlastyCAD software, and 3D printing technology, 10 FTMC (method I) and HWT (method II) were obtained. By preoperative preparation, intraoperative coordination, and postoperative measurement, the brackets were transferred from the trays to the 3D-printed maxillary dental arch models. Additionally, the bracket's excess adhesive as well as linear and angular deviations were measured, and the differences between the two methods were analyzed.

RESULTS

Excess adhesive was observed in both methods, with FTMC showing less adhesive (P< 0.001), with a statistical difference. Furthermore, HWT's vertical, tip and torque, which was significantly greater than FTMC (P< 0.05), with no statistical difference among other respects. The study data of incisors, canines, and premolars, showed that the premolars had more adhesive residue and were more likely to have linear and angular deviations.

CONCLUSIONS

The FTMC had higher bracket bonding effect in comparison to HWT, and the adhesive residue, linear and angular deviations are smaller. The fence tray offers an intuitive view of the precise bonding of the bracket, and can remove excess adhesive to prevent white spot lesions via care, providing a different bonding method for clinical applications.

Deep learning for virtual orthodontic bracket removal: tool establishment and application

OBJECTIVE

We aimed to develop a tool for virtual orthodontic bracket removal based on deep learning algorithms for feature extraction from bonded teeth and to demonstrate its application in a bracket position assessment scenario.

MATERIALS AND METHODS

Our segmentation network for virtual bracket removal was trained using dataset A, containing 978 bonded teeth, 20 original teeth, and 20 brackets generated by scanners. The accuracy and segmentation time of the network were tested by dataset B, which included an additional 118 bonded teeth without knowing the original tooth morphology. This tool was then applied for bracket position assessment. The clinical crown center, bracket center, and orientations of separated teeth and brackets were extracted for analyzing the linear distribution and angular deviation of bonded brackets.

RESULTS

This tool performed virtual bracket removal in 2.9 ms per tooth with accuracies of 98.93% and 97.42% (P < 0.01) in datasets A and B, respectively. The tooth surface and bracket characteristics were extracted and used to evaluate the results of manually bonded brackets by 49 orthodontists. Personal preferences for bracket angulation and bracket distribution were displayed graphically and tabularly.

CONCLUSIONS

The tool's efficiency and precision are satisfactory, and it can be operated without original tooth data. It can be used to display the bonding deviation in the bracket position assessment scenario.

CLINICAL SIGNIFICANCE

With the aid of this tool, unnecessary bracket removal can be avoided when evaluating bracket positions and modifying treatment plans. It has the potential to produce retainers and orthodontic devices prior to tooth debonding.

Do the Various Indirect Bonding Techniques Provide the Same Accuracy for Orthodontic Bracket Placement? (Randomized Clinical Trial)

Background

For orthodontic treatment to be effective, bracket placement must be precise to make the finishing stage easier, leading to an ideal occlusion with minimal intervention. This study aimed to evaluate the accuracy of manual and digital bracket positioning techniques utilizing computer-aided design and computer-aided manufacturing (CAD/CAM) jigs, 3D-printed indirect bonding trays (IBT), and double-layer vacuum-formed thermoplastic IBT.

Methods

This study was done by scanning the dental arch of 30 orthodontic patients. The virtual setup and bracket positioning were performed with the Insignia™ system for ten patients, and 3D Maestro® software was used for the virtual setup of the remaining 20 patients. At the same time, the bracket positioning of 10 patients was done digitally by the 3D Maestro® software and the remaining 10 patients manually through the Ray Set® device. IBT were fabricated by CAD/CAM system, 3D printer, and vacuum-formed thermoplastic machine. A virtual bracket position was compared to the actual bracket position using the best-fit method of 3D digital superimposition in Geomagic® Control X™ (CX) software to determine how accurate it was in terms of linear and angular accuracy. Statistical analyses using SPSS 26.0 including Bland-Altman plots were used to assess the intra-examiner reproducibility. Shapiro-Wilk test was used to measure normality distribution. Wilcoxon matched-pairs signed rank test was used to analyze the differences between bracket positions within each group.

Results

Although there were obvious positional discrepancies between several readings, they were still within clinically acceptable ranges.

Conclusions

All types of IBT would translate the planned position of the bracket from the digital and manual techniques to the teeth of patients with accepted precision in both linear and angular measurements; in addition, the error rate is about the same for all types of IBT. This trial is registered with NCT05549089.

3D printed indirect bonding trays: Transfer accuracy of hard versus soft resin material in a prospective, randomized, single-blinded clinical study

OBJECTIVES

This prospective clinical study aimed to compare transfer accuracy and immediate loss rate of hard versus soft transfer trays utilizing a CAD/CAM workflow.

METHODS

We performed virtual bracket placement on intraoral scans of adolescent patients to create individual indirect bonding trays. Orthodontic software (Appliance Designer, 3Shape, Copenhagen, Denmark) was used to design the trays, which were then produced using 3D printing technology. Patients were randomly assigned to the hard or soft resin groups with a 1:1 allocation. Subgroups were determined based on the Little's Irregularity Index and distributed equally.

RESULTS

552 brackets were bonded onto adolescent patients using 46 CAD/CAM indirect bonding trays. The linear mean transfer errors ranged from -0.011 mm (soft) to -0.162 mm (hard) and angularly -0.255° (hard) and -0.243° (soft). No statistically significant differences were found between the subgroups or soft and hard resin groups. However, the transfer accuracy of molar brackets was significantly lower in the transversal and horizontal directions. All mean transfer errors were within the limits of clinical acceptability. The loss rate was 2.4 % in the hard resin group and 2.3 % in the soft resin group. The Intra Observer Correlation was excellent.

SIGNIFICANCE

CAD/CAM technology for indirect bracket bonding has been proven reliable in a randomized clinical trial. Both hard and soft resin showed a low rate of immediate loss compared to the current literature. Soft resin was more favorable than hard resin in terms of accuracy and usability. However, the indirect bonding of molar brackets is significantly less accurate than incisor brackets.

Transfer Accuracy of 3D-Printed Customized Devices in Digital Indirect Bonding: A Systematic Review and Meta-Analysis

Aim

To evaluate in vitro and in vivo the accuracy of 3D-printed customized transfer devices during indirect bonding technique (IBT).

Methods

A search for articles published in the English language until April 2022 was carried out using PubMed, Web of Science, Scopus, and Google Scholar databases and by applying a specific search strategy for each database to identify all potentially relevant in vivo or in vitro studies. After the removal of duplicate articles and data extraction according to the participants-intervention-comparison-outcome-study design schema scheme, the methodological quality of the included studies was assessed using the Swedish Council on Technology Assessment in Health Care Criteria for Grading Assessed Studies.

Results

The initial search identified 126 articles, 43 of which were selected by title and abstract. After full-text reading, 15 papers were selected for the qualitative analysis and seven studies for the quantitative analysis. The evidence quality for the selected studies was moderate.

Conclusions

Except for the bucco-lingual direction, the 3D-printed customized devices have a transfer accuracy within the clinically acceptable limits established by the American Board of Orthodontics. Therefore, 3D-printed transfer devices may be considered an accurate method for bonding position during IBT, both in vitro and in vivo. Additional randomized clinical studies in vivo should be suggested.

CAD/CAM indirect bonding trays using hard versus soft resin material: a single-blinded in vitro study

OBJECTIVES

The present in vitro study aimed to evaluate the accuracy of three-dimensional (3D) printed indirect bonding trays consisting of hard or soft resin materials produced using computer-aided design and manufacturing (CAD/CAM).

METHODS

Forty-eight dental casts were 3D printed. Four groups based on frontal crowding were defined and divided into hard- and soft-resin groups. After virtual bracket positioning on the digital models, the transfer trays were 3D printed. To evaluate the accuracy of the procedure, measurements were performed using a digital overlay of the virtual (target) bracket position and a post-bonding scan. The horizontal, transverse, and vertical deviations and angular discrepancies were analyzed. The loss rate was evaluated descriptively as a percentage.

RESULTS

A total of 553 brackets were bonded using 24 soft and 24 resilient indirect bonding trays. The mean deviations were of 0.05 mm (transversal), 0.05 mm (horizontal), 0.09 mm (vertical), 0.13° (angulation) in the resilient resin group and of 0.01 mm (transversal), 0.08 mm (horizontal), 0.08 mm (vertical), 0.37° (angular) in the soft resin group. The loss rate was 6.9% and 0.7% in the hard and soft resin groups, respectively. Angular deviations were significantly higher in the soft resin group (P = 0.009), whereas the loss rate was considerably higher in the hard resin group (P < 0.001).

SIGNIFICANCE

The findings indicate that indirect bonding using CAD/CAM is an accurate procedure in the laboratory setting. Soft resins are considered favorable for loss rate and useability.

Clinical Study on Efficiency of Using Traditional Direct Bonding or OrthGuide Computer-Aided Indirect Bonding in Orthodontic Patients

Objective

This study aims to clinically investigate and compare the therapeutic effects and treatment cycle between traditional direct bonding and OrthGuide computer-aided indirect bonding in orthodontic treatment.

Methods

Forty patients treated at the Department of Orthodontics, Beijing Rytime Dental Hospital between July 1, 2016, and December 31, 2019, were included. The patients were divided into a control group (n = 20, traditional direct bonding) and a test group (n = 20, OrthGuide computer-aided indirect bonding). The American Board of Orthodontics (ABO) measurement was performed on patients using Uceph cephalometric analysis software to compare intragroup and intergroup differences, and the treatment cycles of all patients were recorded.

Results

After treatment, U1-NA (mm), ∠U1-SN (°), LL-EP (mm), and UL-EP (mm) in the control group were significantly lower than before treatment, and there was no significant difference in other ABO measurement indexes, while the test group showed no marked difference in all ABO measurements between pre- and posttreatment. Further, intergroup comparison showed no significant difference in ABO measurements in pre- and posttreatment between the two groups. The test group had a shorter treatment cycle than the control group, with an average treatment cycle of 21.20 ± 7.14 months in the control group and 17.17 ± 4.16 months in the test group.

Conclusion

There was no significant difference in the therapeutic effects between the direct and indirect bonding techniques. However, OrthGuide computer-assisted indirect bonding demonstrated a significantly shorter treatment cycle and might be more efficient than traditional direct bonding.

Bracket Transfer Accuracy with the Indirect Bonding Technique-A Systematic Review and Meta-Analysis

Purpose: To investigate the bracket transfer accuracy of the indirect bonding technique (IDB). Methods: Systematic search of the literature was conducted in PubMed MEDLINE, Web of Science, Embase, and Scopus through November 2021. Selection Criteria: In vivo and ex vivo studies investigating bracket transfer accuracy by comparing the planned and achieved bracket positions using the IDB technique were considered. Information concerning patients, samples, and applied methodology was collected. Measured mean transfer errors (MTE) for angular and linear directions were extracted. Risk of bias (RoB) in the studies was assessed using a tailored RoB tool. Meta-analysis of ex vivo studies was performed for overall linear and angular bracket transfer accuracy and for subgroup analyses by type of tray, tooth groups, jaw-related, side-related, and by assessment method. Results: A total of 16 studies met the eligibility criteria for this systematic review. The overall linear mean transfer errors (MTE) in mesiodistal, vertical and buccolingual direction were 0.08 mm (95% CI 0.05; 0.10), 0.09 mm (0.06; 0.11), 0.14 mm (0.10; 0.17), respectively. The overall angular mean transfer errors (MTE) regarding angulation, rotation, torque were 1.13° (0.75; 1.52), 0.93° (0.49; 1.37), and 1.11° (0.68; 1.53), respectively. Silicone trays showed the highest accuracy, followed by vacuum-formed trays and 3D printed trays. Subgroup analyses between tooth groups, right and left sides, and upper and lower jaw showed minor differences. Conclusions and implications: The overall accuracy of the indirect bonding technique can be considered clinically acceptable. Future studies should address the validation of the accuracy assessment methods used.