New virtual orthodontic treatment system for indirect bonding using the stereolithographic technique

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.

Effects of an augmented reality aided system on the placement precision of orthodontic miniscrews: A pilot study

Background/purpose

Augmented reality (AR) is gaining popularity in medical applications, which may aid clinicians in achieving improved clinical outcomes. The purpose of this study was to determine the positional and angle errors of orthodontic miniscrew placement by using a self-developed AR aided system.

Materials and methods

Cone beam computed tomography (CBCT) and patient printed models were used in in vitro experiments. The participants were divided into a control group and an AR group, in which traditional orthodontic methods and the AR-aided system were used respectively. After the information obtained from the CBCT images and navigation system was combined on the display device, the AR-aided system indicated the planned miniscrew position to guide the clinicians during the placement of miniscrews. Both methods were compared by a senior and a junior dentist, and the position and angle of miniscrew placement were statistically analyzed using Wilcoxon's signed-rank and Mann-Whitney U tests.

Results

When the AR-aided system was used, the accuracy of miniscrew placement in the mesiodistal position considerably increased (83%) when the procedure was performed by a senior clinician. In addition, the accuracy of miniscrew placement in the mesiodistal position and the angle of miniscrew placement considerably increased by approximately 67% and 72%, respectively, when the procedure was performed by a junior clinician. The position error of miniscrew placement was smaller for the junior clinician when the AR-aided system was used than for the senior clinician.

Conclusion

The AR-aided system improved the accuracy of miniscrew placement regardless of the clinician's level of experience.

Accuracy of 3-dimensional-printed customized transfer tray using a flash-free adhesive system in digital indirect bonding: An in vivo study

INTRODUCTION

This paper evaluated the accuracy of a computer-aided design and manufacturing indirect bonding technique using a new customized 3D-printed transfer tray and a flash-free adhesive system for orthodontic bonding.

METHODS

This in vivo study analyzed 106 teeth selected from 9 patients undergoing orthodontic treatment. Quantitative deviation analysis was performed to evaluate the bonding positioning errors, assessing the differences between the virtually planned and the clinically transferred bracket position after indirect bonding procedures by superimposing 3-dimensional dental scans. Estimated marginal means were evaluated for individual brackets and tubes, arch sectors, and overall collected measurements.

RESULTS

A total of 86 brackets and 20 buccal tubes were analyzed. Among individual teeth, mandibular second molars showed the highest positioning errors, whereas maxillary incisors reported the lowest values. Considering arch sectors, the posterior areas showed greater displacements than the anterior areas, as the right side compared to the left side, with a higher error rate reported for the mandibular arch than the maxillary arch. The overall bonding inaccuracy measurement was 0.35 mm, below the clinical acceptability limit of 0.50 mm.

CONCLUSIONS

The accuracy of a 3-dimensional-printed customized transfer tray using a flash-free adhesive system in computer-aided design and manufacturing indirect bonding was generally high, with greater positioning errors for posterior teeth.

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.

Accuracy of Orthodontic Indirect Bracket Bonding by CAD/CAM Transfer Tray

Introduction: Indirect bonding is a technique in which orthodontic attachments are transferred from dental casts (working models) and bonded onto dentition using a transfer tray. Indirect bonding is a preferred technique for many orthodontists as it is less time consuming compared to direct bonding. Evolution in technology allowed forming transfer trays digitally by the integration of computer-aided design and computer-aided manufacturing (CAD/CAM). This study was conducted to measure transfer accuracy of CAD/CAM indirect three dimensional printed bonding trays. Materials and methods: 140 teeth (all upper and lower incisors, canines and premolars) in 7 patients were bonded by vacuum-formed transfer tray formed on 3 dimensional (3D) printed models with resin brackets. Intra oral scanner was used initially to obtain stereolithographic file for virtual brackets positioning and another scan was taken after brackets bonding.   Superimposition of virtual STL files and post bonding STL files was done by Geomagic Qualify software to measure linear and angular deviation of brackets positions. Results: One sample t-test was performed to determine whether the mean transfer error was statistically within the selected acceptable limits of 0.5 mm for linear measurements. P-values of less than 0.05 indicated differences within the limits of 0.5 mm for linear measurements. All brackets were transferred within the accepted deviation limits Conclusions: CAD/CAM designed and printed transfer trays had high transfer accuracy in linear measurements in all teeth.

Comparison of Two 3D-Printed Indirect Bonding (IDB) Tray Design Versions and Their Influence on the Transfer Accuracy

Objective: This study aims to investigate the transfer accuracy of two different design versions for 3D-printed indirect bonding (IDB) trays. Materials and Methods: Digital plaster models of 27 patients virtually received vestibular attachments on every tooth using OnyxCeph³™ (Image Instruments, Chemnitz, Germany). Based on these simulated bracket and tube positions, two versions of transfer trays were designed for each dental arch and patient, which differed in the mechanism of bracket retention: Variant one (V1) had arm-like structures protruding from the tray base and reaching into the horizontal and vertical bracket slots, and variant two (V2) had a pocket-shaped design enclosing the brackets from three sides. Both tray designs were 3D-printed with the same digital light processing (DLP) printer using a flexible resin-based material (IMPRIMO® LC IBT/Asiga MAX™, SCHEU-DENTAL, Iserlohn, Germany). Brackets and tubes (discovery® smart/pearl, Ortho-Cast M-Series, Dentaurum, Ispringen, Germany) were inserted into the respective retention mechanism of the trays and IDB was performed on corresponding plaster models. An intraoral scan (TRIOS® 3W, 3Shape, Copenhagen, Denmark) was performed to capture the actual attachment positions and compared to the virtually planned positions with Geomagic© Control (3D Systems Inc., Rock Hill, SC, USA) using a scripted calculation tool, which superimposed the respective tooth surfaces. The resulting attachment deviations were determined in three linear (mesiodistal, vertical and orovestibular) and three angular (torque, rotation and tip) directions and analyzed with a descriptive statistical analysis. A comparison between the two IDB tray designs was conducted using a mixed model analysis (IBM, SPSS® Statistics 27, Armonk, NY, USA). Results: Both design versions of the 3D-printed IDB trays did not differ significantly in their transfer accuracy (p > 0.05). In total, 98% (V1) and 98.5% (V2) of the linear deviations were within the clinically acceptable range of ±0.2 mm. For the angular deviations, 84.9% (V1) and 86.8% (V2) were within the range of ±1°. With V1, most deviations occurred in the mesiodistal direction (3.3%) and in rotation (18%). With V2, most deviations occurred in the vertical direction (3.8%) and in palatinal and lingual crown torque (16.3%). Conclusions: The transfer accuracies of the investigated design versions for 3D-printed IDB trays show good and comparable results albeit their different retention mechanisms for the attachments and are, therefore, both suitable for clinical practice.

Comparison of the transfer accuracy of two digital indirect bonding trays for labial bracket bonding

OBJECTIVES

To compare the transfer accuracy of two digital transfer trays, the three-dimensional printed (3D printed) tray and the vacuum-formed tray, in the indirect bonding of labial brackets.

MATERIALS AND METHODS

Ten digital dental models were constructed by oral scans using an optical scanning system. 3D printed trays and vacuum-formed trays were obtained through the 3Shape indirect bonding system and rapid prototyping technology (10 in each group). Then labial brackets were transferred to 3D printed models, and the models with final bracket positioning were scanned. Linear (mesiodistal, vertical, buccolingual) and angular (angulation, torque, rotation) transfer errors were measured using GOM Inspect software. The mean transfer errors and prevalence of clinically acceptable errors (linear errors of ≤0.5 mm and angular errors of ≤2°) of two digital trays were compared using the Mann-Whitney U-test and the Chi-square test, respectively.

RESULTS

The 3D printed tray had a lower mean mesiodistal transfer error (P < .01) and a higher prevalence of rotation error within the limit of 2° (P = .03) than did the vacuum-formed tray. Linear errors within 0.5 mm were higher than 90% for both groups, while torque errors within 2° were lowest at 50.9% and 52.9% for the 3D printed tray and vacuum-formed tray, respectively. Both groups had a directional bias toward the occlusal, mesial, and buccal.

CONCLUSIONS

The 3D printed tray generally scored better in terms of transfer accuracy than did the vacuum-formed tray. Both types of trays had better linear control than angular control of brackets.

A comparative assessment of transfer accuracy of two indirect bonding techniques in patients undergoing fixed mechanotherapy: A randomised clinical trial

OBJECTIVES

To assess the transfer accuracy of three-dimensional (3D) printed transfer trays and compare them with transfer trays made up of polyvinyl siloxane (PVS) for use in indirect bonding.

DESIGN

This was a two-arm parallel prospective randomised controlled trial.

SETTING

The trial was undertaken at the outpatient department of a dental college.

PARTICIPANTS

A total of 30 patients (18 men, 12 women) were randomly allocated to two groups.

METHODS

The inclusion criteria included patients with permanent and fully erupted dentition (age range = 17-24 years), Angles class I malocclusion with crowding <3 mm requiring non-extraction treatment, good oral hygiene and no previous history of orthodontic treatment. Blinding was applicable only for outcome assessment. Indirect bonding was performed by the primary investigator for both the groups. Digital images of the pre-transfer and post-transfer brackets were obtained by means of an intra-oral scanner and compared using software. Superimpositions of pre- and post-transfer images were done to determine the transfer error for linear and angular variables for all tooth types.

RESULTS

A total of 600 teeth were bonded, 300 each for both groups. Statistically significant differences were observed in all dimension between the two groups, with 3D-printed trays being more accurate than PVS trays except in the vertical dimension (P < 0.05). The prevalence of clinically unacceptable transfer errors revealed that most of the transfer errors were in the vertical dimensions for 3D-printed trays.

CONCLUSION

3D-printed trays are more accurate than PVS trays except for transfers in vertical dimension.

The Indirect Bonding Technique in Orthodontics-A Narrative Literature Review

The technique described as indirect bonding is an alternative to the conventional intraoral method of bracket placement. The appliance position is planned and fixed on a plaster model and then transferred into the oral cavity. Indirect bonding is a precise and time-saving technique of bracket placement, growing in popularity in recent years. It provides a combination of great precision with time efficiency. The fundaments of the indirect bonding technique are presented here. From the first clinical trial conducted almost fifty years ago, the method has evolved; the progress that has been made is described. Modern technologies involving computer scanning and manufacturing have led to great precision in bracket placement. Digital innovations such as rapid prototyping and stereolithography open up a new avenue of research and represent the next steps in indirect technique development. Individual 3D transfers are convenient in difficult clinical cases and can improve the effectiveness of the procedure, reduce the number of technical stages and reduce total chairside time. This paper also summarizes the advancement in adhesive materials, including an overview of advantages and disadvantages of different types of bonding resins and of the mean shear bond strength (SBS) achieved in the indirect procedure.

Reproducibility of digital indirect bonding technique using three-dimensional (3D) models and 3D-printed transfer trays

OBJECTIVE

To evaluate the reproducibility of digital tray transfer fit on digital indirect bonding by analyzing the differences in bracket positions.

MATERIALS AND METHODS

Digital indirect bonding was performed by positioning brackets on digital models superimposed by tomography using Ortho Analyzer (3Shape) software. Thirty-three orthodontists performed indirect bonding on prototyped models of the same malocclusion using prototyped transfer trays for two types of brackets (MiniSprint Roth and BioQuick self-ligating). The models with brackets were scanned using an intraoral scanner (Trios, 3Shape). Superimpositions were made between the digital models obtained after indirect bonding and those from the original virtual setup. To analyze the differences in bracket positions, three planes were examined for each bracket: vertical, horizontal, and angulation. Three orthodontists repeated indirect bonding after 15 days, and Bland-Altman plots and intraclass correlation coefficients were used to evaluate inter- and intraevaluator reproducibility and reliability, respectively. Repeated-measures analysis of variance (ANOVA) was used to analyze the differences between bracket positions, and multivariate ANOVA was used to evaluate the influence of orthodontists' experience on the results.

RESULTS

Differences between bracket positions were not statistically significant, except mesial-distal discrepancies in the BioQuick group (P = .016). However, differences were not clinically significant (horizontal varied from 0.04 to 0.13 mm; angulation, 0.45° to 2.03°). There was no significant influence of orthodontist experience and years of clinical practice on bracket positions (P = .314 and P = .158). The reproducibility among orthodontists was confirmed.

CONCLUSIONS

The reproducibility of digital indirect bonding was confirmed in terms of bracket positions using three-dimensional printed transfer trays.

Accuracy of bracket positions with a CAD/CAM indirect bonding system in posterior teeth with different cusp heights

INTRODUCTION

Our objective was to evaluate the effect of cusp height of posterior teeth (first premolar, second premolar, first molar) on the accuracy of the computer-aided design and computer-aided manufacturing (CAD-CAM) indirect bonding system.

MATERIAL

Five kinds of maxillary arch models, without attrition, were divided into 2 groups: control group (with 0.5 mm of grinding) and experimental group (with the addition of 0.5 mm of wax to the cusp tip). Rapid prototype models were printed for both groups. Transfer jigs of the individual tooth brackets were designed using a digital model. 3-dimensional program to evaluate the differences between the intended digital bracket position and actual bracket position after indirect bonding. The differences were measured in the linear (mesiodistal, buccolingual, vertical) and angular (angulation, rotation, torque) dimensions. The Wilcoxon signed rank test was used for statistical analyses; significance was defined as P <0.05.

RESULTS

Both groups had similar frequencies of errors between the intended and actual bracket positions. The frequencies of vertical errors over 0.5 mm were 3.3% and 6.7% in the control and experimental groups, respectively. The frequencies of angulation, rotation, and torque errors over 1° were 53.3%, 43.3%, and 60%, respectively, for the control group; and 60%, 60%, and 73.3%, respectively, for the experimental group.

CONCLUSIONS

A difference in cusp height of maxillary posterior teeth did not produce a statistically significant difference in the linear and angular dimensions of bracket placement with the CAD/CAM indirect bonding system. However, given the tendency for a higher frequency in bracket placement errors in posterior teeth with larger cusp tips, cusp height should be considered when using a CAD/CAM indirect bonding system.

Virtually fabricated guide for placement of the C-tube miniplate

INTRODUCTION

This paper introduces a virtually planned and stereolithographically fabricated guiding system that will allow the clinician to plan carefully for the best location of the device and to achieve an accurate position without complications.

METHODS

The scanned data from preoperative dental casts were edited to obtain preoperative 3-dimensional (3D) virtual models of the dentition. After the 3D virtual models were repositioned, the 3D virtual surgical guide was fabricated. A surgical guide was created onscreen, and then these virtual guides were materialized into real ones using the stereolithographic technique.

RESULTS

Whereas the previously described guide required laboratory work to be performed by the orthodontist, our technique is more convenient because the laboratory work is done remotely by computer-aided design/computer-aided manufacturing technology. Because the miniplate is firmly held in place as the patient holds his or her mandibular teeth against the occlusal pad of the surgical guide, there is no risk that the miniscrews can slide on the bone surface during placement. The software program (2.5-dimensional software) in this study combines 2-dimensional cephalograms with 3D virtual dental models. This software is an effective and efficient alternative to 3D software when 3D computed tomography data are not available.

CONCLUSIONS

To confidently and safely place a miniplate with screw fixation, a simple customized guide for an orthodontic miniplate was introduced. The use of a custom-made, rigid guide when placing miniplates will minimize complications such as vertical mislocation or slippage of the miniplate during placement.

Accuracy of a cone beam computed tomography-guided surgical stent for orthodontic mini-implant placement

OBJECTIVE

To validate the accuracy of a cone-beam computed tomography (CBCT)-guided surgical stent for orthodontic mini-implant (OMI) placement by quantitatively evaluating the difference between CBCT-prescribed and actual position of mini-implants in preoperative and postoperative CBCT images.

MATERIALS AND METHODS

A surgical stent was fabricated using Teflon-Perfluoroalkoxy, which has appropriate biological x-ray attenuation properties. Polyvinylsiloxane impression material was used to secure the custom-made surgical stent onto swine mandibles. CBCT scanning was done with the stent in place to virtually plan mini-implants using a three-dimensional (3D) software program. An appropriate insertion point was determined using 3D reconstruction data, and the vertical and horizontal angulations were determined using four prescribed angles. A custom-designed surveyor was used to drill a guide hole within the surgical stent as prescribed on the CBCT images for insertion of 32 OMIs. The mandibles with a surgical stent in place were rescanned with CBCT to measure the deviations between the virtual planning data and surgical results.

RESULTS

The difference between the prescribed and actual vertical angle was 1.01 ± 7.25, and the horizontal difference was 1.16 ± 6.08. The correlation coefficient confirms that there was no intrarater variability in either the horizontal (R  =  .97) or vertical (R  =  .74) vectors.

CONCLUSIONS

The surgical stent in this study guides mini-implants to the prescribed position as planned in CBCT. Since the statistical difference was not significant, the surgical stent can be considered to be an accurate guide tool for mini-implant placement in clinical use.