This prospective clinical study aimed to compare transfer accuracy and immediate loss rate of hard versus soft transfer trays utilizing a CAD/CAM workflow.
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.
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.
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.
•First clinical study evaluating transfer accuracy of 3D printed indirect orthodontic bonding trays using hard or soft material.•CAD/CAM technology was applied for digital bracket positioning and 3D printing of the transfer trays.•Hard and soft transfer trays have been shown to be accurate in a clinical setting.•Trays made of soft bonding material showed a lower rate of immediate loss and are favorable in clinical use.
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.
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).
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.
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.
To compare the transfer accuracy of two different three-dimensional printed trays (Dreve FotoDent ITB Dreve Dentamid, Unna, Germany and NextDent Ortho ITB NextDent, Soesterberg, the Netherlands) to ...polyvinyl siloxane (PVS) trays for indirect bonding.
A total of 10 dental models were constructed for each investigated material. Virtual bracket placement was performed on a scanned dental model using OnyxCeph (OnyxCeph 3D Lab, Chemnitz, Germany). Three-dimensional printed transfer trays using a digital light processing system three-dimensional printer and silicone transfer trays were produced. Bracket positions were scanned after the indirect bonding procedure. Linear and angular transfer errors were measured. Significant differences between mean transfer errors and frequency of clinically acceptable errors (<0.25 mm/1°) were analyzed using the Kruskal-Wallis and χ2 tests, respectively.
All trays showed comparable accuracy of bracket placement. NextDent exhibited a significantly higher frequency of rotational error within the limit of 1° (P = .01) compared with the PVS tray. Although PVS showed significant differences between the tooth groups in all linear dimensions, Dreve exhibited a significant difference in the buccolingual direction only. All groups showed a similar distribution of directional bias.
Three-dimensional printed trays achieved comparable results with the PVS trays in terms of bracket positioning accuracy. NextDent appears to be inferior compared with PVS regarding the frequency of clinically acceptable errors, whereas Dreve was found to be equal. The influence of tooth groups on the accuracy of bracket positioning may be reduced by using an appropriate three-dimensional printed transfer tray (Dreve).
The aim was to investigate the influence of three different three-dimensional (3D)-printed bonding tray designs and professional experience on accuracy of indirect bracket placement.
Virtual bracket ...placement was performed on a scanned dental model using OnyxCeph software (Image Instruments, Chemnitz, Germany). Three different designs for indirect bonding trays (open, semi-open, and closed design) were created and produced using a 3D printer. To analyze the influence of professional experience, one of the three tray designs was produced twice. In this case, bracket placement was performed by an inexperienced dentist. Bracket positions were scanned after the indirect bonding procedure. Linear and angular transfer errors were measured. Significant differences between the target and actual situation were analyzed using the Kruskal-Wallis and χ
test.
All bonding tray designs resulted in comparable results. The results of the unexperienced dentist showed significantly higher deviations than those for the experienced orthodontist in the torque direction. However, the mean values were comparable. The open tray design exceeded the clinically acceptable limits of 0.25 mm and 1° more often. The inexperienced dentist exceeded these limits significantly more often than the experienced orthodontist in the vertical and torque direction. The immediate bracket loss rate showed no significant differences between the different tray designs. Significantly more bracket losses were observed for the inexperienced dentist during the procedure compared to the experienced orthodontist.
The bonding tray design and professional experience had an influence on the exceedance of clinically relevant limits of positioning accuracy and on the bracket loss rate.
AIMThe positional accuracy of bracket placement planned through tooth setup vs actual placement was evaluated by means of conventional thermoplastic indirect bonding trays and customized 3D-printed ...indirect bonding trays. MATERIALS AND METHODSA total of 280 bracket positions placed on the crowns of 10 dental plaster models were evaluated. The manual setup method and a thermoplastic indirect bonding tray were used for the manual group. For the CAD/CAM group, the bracket was positioned using a digital setup and a corresponding 3D-printed tray. The positional accuracy of the bracket placement on the duplicated gypsum model using the trays was evaluated by means of 3D software. Six errors of bracket position (height, depth, mesiodistal, torque, rotation, and tip errors), including linear and angular errors, were measured. Differences in variables were compared across subgroups using the independent t test or the Mann-Whitney U test. RESULTSOnly the height error differed significantly (P < 0.05) between groups (manual: 0.2 mm; CAD/CAM: 0.12 mm). For both incisors and molars, the manual group showed significantly greater height errors than the CAD/CAM group (P < 0.05). The analysis of variance of the position error to the whole bracket showed statistically significant differences between tooth positions, linear measurements, and angular measurements (P < 0.05). CONCLUSIONA 3D-printed indirect bonding tray showed accuracy similar to that of conventional methods for bracket placement, with slightly greater bracket height accuracy. Further studies should strive to improve accuracy in terms of tooth positions.
In the current study, we aimed to evaluate the accuracy of indirect bonding by either three-dimensional (3D) printing guides or double-layer guide plates. The results may serve as a clinical ...reference for bracket placements.
In total, 140 teeth were collected and arranged into five pairs of full dentition. The marking points were labeled on the buccal/labial surface of the crown in these orthodontic study models. (1) 3D printing guide: A digital profile was generated using an intraoral scanner. Two types of indirect bonding guide, namely the whole denture type and the single tooth type, were designed with the 3Shape TRIOS® Standard intraoral scanner and fabricated using 3D printing technology. (2) Double-layer guide plate: A working model was obtained by replicating the experimental models, and the double-layer guide plate was then made of the inner layer soft film (1.0 mm thickness) and the outer layer hard film (0.6 mm or 0.8 mm thickness). Brackets were transferred from working models to study models by the indirect bonding trays. We measured and analyzed the distance between marking points and bracket placement. Statistical analysis was done using SPSS 20.0 software. The accuracy of indirect bonding between 3D printing guide and double-layer guide plate was compared using paired t-test.
According to our data, there was a significant difference between the 0.6 mm group and 0.8 mm group when the brackets were indirectly adhered using double-layer guide plates (p = 0.036). However, no statistical significance in bracket positioning accuracy was revealed between two types of 3D printing guide (p = 0.078), as well as between the 3D printing guide group and the 0.6 mm double-layer guide plate group (p = 0.069).
When applying double-layer guide plates for indirect bonding, the 0.6 mm group is more accurate than the 0.8 mm group. When utilizing 3D printing guides for indirect bonding, whole denture type is more accessible than single tooth type but with no significant difference in accuracy. The accuracy of indirect bonding is comparable when using 3D printing guides (whole denture type) and double-layer guide plates (0.6 mm).
To examine the ultimate accuracy of bracket placement in labial vs lingual systems and in direct vs indirect bonding techniques.
Forty pretreatment dental casts of 20 subjects were selected. For each ...dental cast, four types of bracket placement were compared: labial direct (LbD), labial indirect (LbI), lingual direct (LgD), and lingual indirect (LgI). Direct bonding was performed with the casts held in a mannequin head. Labial brackets were oriented with a Boone gauge, and lingual brackets were oriented with the Lingual-Bracket-Jig System. Torque error (TqE) and rotation deviation (RotD) were measured with a torque geometric triangle and a toolmaker's microscope, respectively. Both torque and rotational measurements were evaluated statistically as algebraic and absolute numeric values, using analysis of variance with repeated measures.
Absolute TqE and RotD were significantly (P < .001) higher in direct than in indirect bonding techniques higher in both the labial and lingual bracket systems by twofold and threefold, respectively (LbD = 7.26 degrees , 1.06 mm; vs LbI = 3.02 degrees , 0.75 mm; LgD = 8.42 degrees , 1.13 mm; vs LgI = 3.18 degrees , 0.55 mm). No statistically significant difference was found between labial and lingual systems for the same bonding technique. Maxillary incisors demonstrated the largest RotD angle (eg, right lateral: 12.04 degrees ). A distal off-center RotD was predominant in the mandibular dentition.
Labial and lingual systems have the same level of inaccuracy. For both systems, indirect bonding significantly reduces absolute TqE and RotD. The TqE found can cause transverse discrepancy (scissors or crossbite) combined with disclusion with antagonist teeth. The RotD found can result in irregular interproximal contact points.
In orthodontics the precise location of bracket placement on the teeth is a goal in order to individualize and optimize treatment outcome. The authors will describe the indirect bonding procedure ...with thermal glue transfer tray and brackets with positioning jigs for precise bracket placement.
PDF
