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

Accuracy of digital indirect bonding technology for customized orthodontic brackets based on personalized typodonts

OBJECTIVE

The chief aim of this study was to confirm the accuracy and repeatability of digital indirect bonding (IDB) by simulating customized clinical orthodontic procedures with personalized typodonts from the perspective of orthodontic outcomes.

METHODS

Five personalized typodonts were produced with 3D-printing technology to mimic straight-wire orthodontic procedures. The digital IDB was employed to position the customized brackets. After treatment, the PAR index, the ABO-OGS index and the occlusal contact area were analyzed. The matching degree between the target position and the posttreatment position on typodonts was assessed with Geomagic Control X.

RESULTS

The mean arch discrepancy between the personalized typodonts and the initial intraoral scan model was 0.15 mm ± 0.01 mm in the maxilla and 0.20 mm ± 0.01 mm in the mandible. Following customized orthodontic therapy, the PAR Index decreased from 29 to 1, the ABO-OGS Index was 13.8 ± 0.84, and the occlusal contact area increased 4.04mm2 ± 1.14mm2, with the bilateral occlusal contact area becoming equally distributed. The mean arch discrepancy between the target position and the actual posttreatment positions was 0.15 mm ± 0.01 mm in the maxilla and 0.16 mm ± 0.01 mm in the mandible.

CONCLUSIONS

Digital IDB is conducive to locating the brackets in the target position to precisely achieve the ideal therapeutic outcome of customized orthodontic systems on the personalized typodont. The customized bracket design and the digital IDB can lead orthodontics in a more accurate, visual, and predictable direction.

Three-Dimensional-Printed Photopolymer Resin Materials: A Narrative Review on Their Production Techniques and Applications in Dentistry

Additive manufacturing (3D printing) has transformed dentistry by providing solutions with high precision and accuracy achieved through digital workflows, which facilitate the creation of intricate and personalized structures. Additionally, 3D printing promotes cost efficiency by reducing material waste and errors while enabling on-demand production, minimizing the need for extensive inventories. Recent advancements in 3D-printed resin materials have enhanced their clinical applications by improving mechanical strength, biocompatibility, esthetics, and durability. These innovations have facilitated the fabrication of complex and patient-specific structures, such as dental prostheses, surgical guides, and orthodontic appliances, while significantly reducing production time and material waste. Ongoing research and innovation are expected to strengthen resin properties, including strength, translucency, and durability, broadening their clinical applications. The ongoing evolution of 3D printing technology is poised to play a critical role in driving personalized treatments, streamlining clinical workflows, and shaping the future of dental care. This narrative review comprehensively examines the production techniques and clinical applications of 3D-printed photopolymer resins across various dental specialties, including prosthodontics, orthodontics, pediatric dentistry, maxillofacial surgery, periodontology, endodontics, and conservative dentistry. Additionally, the review provides insight into the transformative impact of these technologies on patient care, highlights existing challenges, and suggests future directions for advancing resin properties and their integration into routine dental practice.

Comparison of 1- and 3-piece directly 3-dimensional printed indirect bonding trays: An in vitro study

INTRODUCTION

This study aimed to compare the transfer accuracy of indirect bonding trays of different thicknesses and numbers of pieces.

METHODS

Digital indirect bonding was performed on 56 printed resin models, divided into 4 groups with 14 models in each: 1-mm 1-piece tray (OPT), 2-mm OPT, 1-mm 3-piece tray (TPT), and 2-mm TPT. The trays were designed using Appliance Designer (3Shape A/S, Copenhagen, Denmark). Angular (torque, tip, or angulation) and linear (mesiodistal, buccolingual, occlusogingival, or vertical) differences were compared by using open-source GOM Inspect software (GOM GmbH, Braunschweig, Germany).

RESULTS

In the buccolingual direction, the 1-mm TPT (0.180 ± 0.041 mm) was significantly more accurate than the 1-mm OPT (0.240 ± 0.032 mm). In the vertical direction, significant differences were seen between the 1-mm and 2-mm OPTs (1-mm OPT: 0.220 ± 0.043 mm; 2-mm OPT: 0.428 ± 0.143 mm; P = 0.003) and between the 1-mm and 2-mm TPTs (1-mm TPT: 0.210 ± 0.072 mm; 2-mm TPT: 0.340 ± 0.062 mm; P = 0.004) in the total region. In the tip angle, significant differences were seen between the 1-mm and 2-mm OPTs and between the 1-mm OPT and TPT. In the torque angle, a significant difference was seen between the 1-mm TPT (2.815°±0.350°)and 2-mmTPT (2.368° ± 0.245°; P = 0.017).

CONCLUSIONS

Both the thickness and the splitting of the trays impacted the bracket bonding accuracy. The 1-mm trays were more accurate than the 2-mm trays. Despite a few statistically significant differences between the 1-mm OPT and TPT, the 1-mm OPT was recommended for clinical use, considering the designing and placing of the trays.

Transfer accuracy of 3D printed versus CAD/CAM milled surgical guides for temporary orthodontic implants: A preclinical micro CT study

OBJECTIVES

Temporary anchorage devices (TADs) have become an integral part of comprehensive orthodontic treatments. This study evaluated the transfer accuracy of three-dimensional (3D) printed and computer-aided design/computer-aided manufacturing (CAD/CAM) milled surgical guides for orthodontic TADs using micro-computed tomography (CT) imaging in a preclinical trial.

METHODS

Overall, 30 surgical guides were used to place TADs into typodonts; 3D printing and CAD/CAM milling were used to produce the guides. The virtual target positions of the TADs were compared to the real positions in terms of spatial and angular deviations using digital superimposition. Micro-CT imaging was used to detect the positions. To evaluate reliability, two investigators collected the measurements twice. Intra-rater and inter-rater correlations were tested.

RESULTS

In total, 60 palatal TADs were evaluated. The mean coronal deviations in the print group ranged from 0.15 ± 0.20 mm to 0.71 ± 0.22 mm, whereas in the mill group, they ranged from 0.09 ± 0.15 mm to 0.83 ± 0.23 mm. At the apical tip, the overall deviations in the print group ranged from 0.14 ± 0.56 mm to 1.27 ± 0.66 mm, whereas in the mill group, they ranged from 0.15 ± 0.57 mm to 1.09 ± 0.44 mm. The mean intra-class and inter-class correlation coefficients ranged from 0.904 to 0.987. No statistically significant differences were found between the groups.

CONCLUSIONS

CAD/CAM milled guides yielded spatial and angular accuracies comparable to those of 3D printed guides with notable deviations in the vertical positioning of TADs.

CLINICAL SIGNIFICANCE

Digital planning of orthodontic temporary implants combines clinical predictability and the safety of surrounding tissue. Therefore, the transfer accuracy of the guides is crucial. This preclinical study was the first to evaluate CAD/CAM milling for orthodontic guides and found its accuracy comparable to that of the current "gold standard".