CAD/CAM-based 3D-printed and PVS indirect bonding jig system accuracy: a systematic review, meta-analysis, and comparative analysis of hard and soft CAD/CAM transfer trays.

BACKGROUND: The widespread use of CAD/CAM transfer trays warrants evaluation of their accuracy as compared to PVS transfer trays. OBJECTIVES: To quantify the accuracy of CAD/CAM and PVS transfer trays, investigating any differences between soft and hard trays CAD/CAM transfer trays. SEARCH METHODS: Eight different databases (Scopus, Web of Science, PubMed, Google Scholar, ProQuest, Embase, Cochrane Library, ClinicalTrials.gov) were searched, without restrictions, up to an end date of February 2023. SELECTION CRITERIA: Clinical trials (randomized and non-randomized) and in vitro studies reporting average imprecision values for bracket positioning obtained by digital superimpositions of digitally planned and real positions. DATA COLLECTION AND ANALYSIS: Data eligibility, data extraction, and risk of bias (RoB-2 and ROBINS-I) were conducted independently. The data, where possible, were synthesized and quantitatively analysed (meta-analysis of mean differences with 95% confidence intervals). The Grade of Recommendation, Assessment, Development and Evaluation (GRADE) analysis of the quality of evidence was performed. The t-test for independent samples was used to compare the transfer accuracy of hard and soft CAD/CAM transfer trays. RESULTS: Thirteen studies were synthesized in this systematic review, and then eight studies were included in the quantitative meta-analysis. As regards linear measurements, there was a mean transfer error of 0.0752 mm (95%CI: 0.0428, 0.1076) for mesiodistal measures, 0.0943 mm (95%CI: 0.0402, 0.1484) for vertical, and 0.0815 mm (95%CI: 0.0469, 0.1160) for buccolingual. As for angular measurements, there was an average transfer error of 1.2279° (95% CI: 0.6011, 1.8548) for inclination, 0.9397° (95%CI: 0.4672, 1.4123) for angulation, and 0.8721° (95%CI: 0.4257, 1.3185) for rotation. CAD/CAM transfer trays were less accurate than polyvinylsiloxane (PVS) transfer trays, with those made of soft material being more accurate than the hard ones, except for vertical dimension. The GRADE quality of evidence ranged from very low to moderate. CONCLUSIONS AND IMPLICATIONS: CAD/CAM transfer trays provide high bracket positioning accuracy, with soft transfer trays offering greater precision than rigid ones. Future randomized prospective trials are required to enhance the strength of the available evidence. REGISTRATION: Prospero (CRD42023401278 number).

Accuracy of indirect bonding trays - a measurement algorithm.

AIM: To present an image-processing measurement algorithm to evaluate the transfer accuracy of indirect bonding (IDB) trays, exemplified by a CAD/CAM-based IDB tray integrated into a digital orthodontic workflow. MATERIALS AND METHODS: Plaster casts of 24 patients with full dentition and different malocclusions were scanned with an intraoral scanner (Trios; 3Shape, Copenhagen, Denmark) to obtain digital models, which served for the virtual placement of orthodontic brackets in simulation software (OnyxCeph; Image Instruments, Chemnitz, Germany). The resulting STL files were sent to a dental laboratory (CA Digital; Hilden, Germany) for the production of INDIVIDUA IDB trays. These trays were used to transfer the brackets to the respective plaster casts. Finally, a second scan was performed to record the actual bracket positions. The transfer accuracy was then analyzed by a measurement algorithm scripted to automation, which calculated the deviations of the planned and real bracket positions with a local best-fit alignment, resulting in three linear and three angular measurements for each bracket. RESULTS: In total, 622 brackets and tubes were transferred successfully. The presented algorithm analyzed the transfer accuracy and demonstrated that the linear measurements were 98.3% within the range of the American Board of Orthodontics standard. The angular measurements were 86.7% within this range when the INDIVIDUA IDB tray was used. CONCLUSION: Scripted measurement algorithms facilitated the evaluation of present and future materials and designs for IDB trays to obtain an efficient solution for orthodontic practice. The INDIVIDUA IDB tray is a digital alternative to conventional IDB trays (Int J Comput Dent 2022;25(3):295-302; doi: 10.3290/j.ijcd.b2599775).

Comparison of Bracket Failure Rate between Two Different Materials Used to Fabricate Transfer Trays for Indirect Orthodontic Bonding.

BACKGROUND: Various techniques have been advocated for over half a century for the fabrication of transfer trays for indirect orthodontic bonding. Authors have aimed to provide better light curing and accuracy of bracket positioning to avoid bracket failure and get the best possible results. AIM: This study is aimed to compare bracket failure rate when transfer trays were fabricated with a glue gun material and polylactic acid (PLA) filament for an indirect bonding procedure. MATERIALS AND METHODS: Customized transfer trays were fabricated using a glue gun material and PLA filament, and an indirect bonding procedure was performed. Bracket failure was assessed at regular intervals with adhesive remnant index (ARI) scoring, and reasons for bracket failure were assessed. RESULTS: Kolmogorov-Smirnov test was employed to test the normality of data. A Chi-square test was performed for the quantitative variables. Results showed higher bracket failure in the PLA transfer tray groups and in the mandibular arch, especially in the posterior region. Adhesive remnant index scores of 2 followed by 3 were prevalent, and the most common reason for bracket failure was an excessive force during PLA transfer tray retrieval followed by masticatory forces. CONCLUSIONS: Both the transfer tray methods are effective for an indirect bonding procedure. Polylactic acid transfer trays showed more bracket failure as compared to glue gun transfer trays, especially in the mandibular posterior region due to excessive force applied during tray retrieval. CLINICAL SIGNIFICANCE: This study aims to provide valuable information regarding the efficiency of various in-house methods of fabricating customized transfer trays and their effect on bracket failure rates.

Construction of an In Vivo Debonding Device and Comparison of Bracket Failure Rate and Debonding Force for Indirect Orthodontic Bonding.

AIM: A major limitation of indirect bonding is incomplete penetration of the curing light through transfer trays, leading to inadequate curing of light-cure adhesive resin, causing bracket bond failure. Dual-cure adhesive resin is both light and chemically cured, which reduces the requirement of light for curing of the composite. Comparative evaluation of bracket failure rate and bond strength between dual-cure composite and light-cure composite for indirect orthodontic bonding of brackets. MATERIALS AND METHODS: A split-mouth randomized clinical study was carried out in 51 patients (30 females and 21 males). Indirect orthodontic bonding using Erkogum as adhesive to attach the bracket to cast and glue gun material was utilized to form a transfer tray. Conventional light-cure and dual-cure adhesive resins were compared with regard to their bracket failure rate, adhesive remnant index score, and in vivo clinical bond strength. RESULTS: Kolmogorov-Smirnov test was employed to test the normality of data. Mann-Whitney U test and Chi-square test were performed for the quantitative variables and it was observed that both the groups showed similar results for the parameters being measured. The mandibular arch showed more bracket failure, the dual-cure composite group showed more bracket failure, however, the adhesive remnant index (ARI) score for both the groups was similar. No statistically significant difference was seen concerning the clinical bond strength between the two adhesive resins. CONCLUSION: Dual-cure adhesive system can be used for indirect bonding in orthodontics. The mandibular arch had a higher bond failure in the second premolar region. The sequence of bond failure was concordant among both the adhesive groups. However, dual-cure adhesive invariably showed more bracket failure. The highest bond strength was observed for the maxillary canine brackets in the light-cure group, and mandibular canine brackets in the dual-cure group. Whereas, the weakest bond strength in the light-cure group was observed for the mandibular second premolar brackets and for maxillary second premolar brackets in the dual-cure group. There was no significant difference between the in vivo clinical bond strength between the two adhesive systems. On debonding, majority of the adhesive was observed to be on the tooth surface. CLINICAL SIGNIFICANCE: This study signifies that both light-cure and dual-cure resins can be used for indirect bonding procedures but light-cure composite resin shows a lower bracket failure rate as compared to dual-cure composite resin.

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

Accurate bracket placement is essential for successful orthodontic treatment. An indirect bracket bonding system (IDBS) has been developed to ensure proper bracket positioning with three-dimensional computer-aided transfer jigs. The purpose of this study was to investigate the accuracy of bracket positioning by a one-body transfer jig according to the tooth type and presence/absence of a resin base. In total, 506 teeth from 20 orthodontic patients were included in this study. After initial dental models were scanned, virtual setup and bracket positioning procedures were performed with 3D software. Transfer jigs and RP models were fabricated with a 3D printer, and brackets were bonded to the RP model with or without resin base fabrication. The best-fit method of 3D digital superimposition was used to evaluate the lineal and angular accuracy of the actual bracket position compared to a virtual bracket position. Although all the measurements showed significant differences in position, they were clinically acceptable. Regarding the tooth types, premolars and molars showed higher accuracy than anterior teeth. The presence or absence of a resin base did not consistently affect the accuracy. In conclusion, the proper application of IDBS should be performed considering the errors, and resin base fabrication might not be essential in ensuring high-accuracy IDBS.

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.

3D Printing Pen: A Novel Adjunct for Indirect Bonding.

BACKGROUND: Direct orthodontic bracket bonding consumes significantly more chairside time in comparison to indirect bonding. The primary drawback of indirect bonding is incomplete penetration of the curing light through transfer trays, leading to bracket bond failure. The primary objective in a clinical setting is to minimize the chairside time. This technique of indirect bonding reduces chairside time, is economical, utilizes minimum armamentarium, and provides adequate light penetration and accuracy. TECHNIQUE: Impressions were made, casts were poured and marked for the desired bracket position as per MBT prescription. Bonding agent was used to stabilize the brackets on the working model. A 3D printing pen and polylactic acid (PLA) filament were used to fabricate transfer trays for indirect bonding. The tray with brackets held in the desired position was transferred to the oral cavity and cured. CONCLUSIONS: Fabrication of complete or partial transfer trays for indirect bonding using PLA with the help of a 3D printing pen is a precise, easy-to-use, economical, and reliable method that reduces chairside time. CLINICAL SIGNIFICANCE: When compared with other methods of indirect bonding, the PLA transfer tray made with a 3D printing pen was easy to fabricate with brackets held firmly in the tray for a precisely desired position. The tray fit snugly and permitted light curing of composite from all surfaces of brackets and removal of flash. This method significantly reduced the overall time of the indirect bonding procedure.

Accuracy evaluation of bracket repositioning by indirect bonding: hard acrylic CAD/CAM versus soft one-layer silicone trays, an in vitro study.

OBJECTIVES: Rapid development of digital technologies and 3D printing provide new tools for orthodontic indirect bonding. The purpose of this in vitro study is to evaluate the clinical acceptability of hard CAD/CAM indirect bonding tray. MATERIAL AND METHODS: Ten soft silicone transfer trays and ten hard CAD/CAM trays were produced, and 200 brackets were placed on them. The brackets were then transferred to twenty stereolithography -printed models by indirect bonding. These models were scanned and digitally compared with the reference model by three-dimensional superimpositions (GOM software). The linear and angular measurements were collected and analyzed. RESULTS: For the CAD/CAM trays, 100% of the mesiodistal, vertical, and transverse measurements of incisors were within the clinically acceptable range of the American Board of Orthodontists (ABO) standards. More specifically, the clinically acceptable linear measurements were between 97 and 100% for silicone trays while they were between 89 and 100% for CAD/CAM trays. The clinically acceptable angular measurements varied between 87 and 100% for the silicone trays and between 79 and 100% for the CAD/CAM trays. Silicone trays were more precise than CAD/CAM trays. The difference was significant for all linear and angular measurements. CONCLUSIONS: While the CAD/CAM group shows clinically acceptable results according to the ABO, silicone remains to be more precise than CAD/CAM for transfer trays and is therefore still the reference. CLINICAL RELEVANCE: We demonstrate here that the orthodontic indirect bondings, whether they are realized using silicone transfer trays or CAD/CAM trays, are clinically acceptable in terms of the repositioning accuracy of brackets.

The digital POIP concept: Preorthodontic implant placement.

OBJECTIVE: The aim of this report is to present an interdisciplinary treatment involving periodontics, orthodontics, dental implant placement, and prosthodontics with a fully digital dentistry approach. CLINICAL CONSIDERATIONS: The patient presented with an edentulous ridge on the area of the lower left lateral incisor as well as gingival recession on the adjacent teeth. After performing a digital orthodontic setup and indirect bonding bracket placement, a dental implant placement was carried out before orthodontic treatment in combination with guided bone regeneration (GBR), connective tissue graft (CTG) and periodontal accelerated osteogenic orthodontics (PAOO). In a 6-month period, orthodontic treatment was fully completed and the dental implant was restored at 8 months. Following one-and-a-half years, significant gingival recession reduction was accomplished and soft tissue augmentation around the dental implant appeared stable with a good functional and esthetic result. CONCLUSION: The use of the digital POIP concept with a proper diagnosis and careful planning is crucial for reducing treatment time and enhancing precision.

Comparison of three-dimensional printing guides and double-layer guide plates in accurate bracket placement.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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).

Effectiveness, efficiency and adverse effects of using direct or indirect bonding technique in orthodontic patients: a systematic review and meta-analysis.

BACKGROUND: The direct and indirect bonding techniques are commonly used in orthodontic treatment. The differences of the two techniques deserve evidence-based study. MATERIALS AND METHODS: Randomized controlled trials (RCTs), wherein direct and indirect bonding techniques were used in orthodontic patients were considered. The MEDLINE, EMBASE, CENTRAL and Web of Science databases were searched to identify relevant articles published up to December 2018. Grey literature was also searched. Two authors performed data extraction independently and in duplicate using the data collection form. The included trials were assessed using the Cochrane risk of bias assessment tool. RESULTS: Of the 1557 studies screened, 42 full articles were scrutinized and assessed for eligibility. Eight RCTs (247 participants) were finally included for the analyses. The qualitative synthesis showed that no significant difference existed in the accuracy of bracket placement and oral hygiene status between the two bonding techniques. The indirect bonding was found to involve less chairside time but more total working time compared with the direct bonding. The meta-analysis on bond failure rate demonstrated no significant difference between the direct and indirect bonding (RR = 1.13, 95% CI = 0.78-1.64, I2 = 22%, P = 0.50). Consistent results were obtained in the subgroup analyses and sensitivity analyses. CONCLUSION: Weak evidence suggested that the direct and indirect bonding techniques had no significant difference in bracket placement accuracy, oral hygiene status and bond failure rate, for bonding orthodontic brackets. The indirect bonding might require less chairside time but more total working time in comparison with the direct bonding technique. High-quality well-designed randomized controlled trials are needed before a conclusive recommendation could be made.

In vitro and in vivo comparison of orthodontic indirect bonding resins: A prospective study.

OBJECTIVE: The aim of this study was to evaluate in vitro shear bond strength (SBS) and in vivo bond survival rates of brackets bonded using orthodontic indirect bonding resins. MATERIALS AND METHODS: For the in vitro study, the first group was direct bonding control group. In Groups II and III, bonding was performed with indirect bonding resins that were either chemically or light-cured. The SBS of each sample was examined. For the in vivo study, full-mouth brackets were placed in 20 patients using a split-mouth approach, with either chemically-cured or a light-cured indirect bonding resin. The patients were followed for 12 months. Data were statistically evaluated using analysis of variance, Tukey's tests, and Weibull survival analysis. RESULTS: The mean SBS values (MPa) were 17.6 ± 6.6, 13.1 ± 4.7, and 15.1 ± 5.9 for Group I, Groups II, and III, respectively, (P < 0.05). The adhesive remnant index scores of the groups were generally Score 3 and Score 4. In vivo follow-up showed no statistically significant differences in total bond failure rate between groups (P > 0.05). CONCLUSIONS: In vitro study showed lower SBS with chemically-cured indirect bonding resin than flowable light-cured resin and the control group, but in vivo failure rates of both indirect resins were found to be adequate for clinical usage.

Self ligating lingual appliance.

Adult demand for orthodontics has grown considerably over the past 10 years propelling increased demand for Esthetic Orthodontics. Lingual appliances are a viable option toward providing Esthetic Orthodontics. The lingual surface of the teeth has a unique morphology that makes it difficult to place brackets in ideal positions. Indirect bonding has become the established methods of overcoming these discrepancies, along with the latest designs of self ligating brackets which offer more efficient mechanics and shorter treatment time.

Influence of different methods of cleaning custom bases on the shear bond strength of indirectly bonded brackets.

OBJECTIVE: To determine the influence on shear bond strength and bond failure location of four cleaning methods for orthodontic bracket custom bases. DESIGN: In vitro laboratory study. MATERIAL AND METHODS: Eighty bovine teeth were divided at random into four groups. The bracket custom bases were cleaned with different methods: group 1 with methyl methacrylate monomer, group 2 with acetone, group 3 with 50 µm aluminium oxide particles and group 4 with detergent. The brackets were indirectly bonded onto the teeth with the Sondhi Rapid-Set self-curing adhesive. The maximum required shear bond strength to debond the brackets was recorded. The bond failure location was evaluated using the Adhesive Remnant Index (ARI). One-way analysis of variance (ANOVA) analysis (P<0·05) was used to detect significant differences in the bond strength. Kaplan-Meier survival plots and log-rank test were done to compare the survival distribution between the groups. The Kruskal-Wallis test (P<0·05) was used to evaluate the differences in the ARI scores. RESULTS: The mean bond strengths in groups 1, 2, 3 and 4 were 23·7±5·0, 25·3±5·1, 25·6±3·7 and 25·7±4·2 MPa, respectively. There were no significant statistically differences in either the bond strength or the ARI score between the groups. CONCLUSION: The four custom base-cleaning methods presented the same efficiencies on indirect bond of the brackets; thus, practitioners can choose the method that works best for them.

Does clinical experience affect the bracket bonding accuracy of guided bonding devices in vitro?

OBJECTIVES: To study whether and how the clinical experience of the operator affects the accuracy of bracket placement using guided bonding devices (GBDs) in vitro. MATERIALS AND METHODS: Five resin models were bonded virtually with brackets, and the corresponding GBDs were generated and three-dimensionally printed. Nine operators, which included three dental students, three orthodontic students, and three orthodontists, bonded the brackets on the resin models using GBDs on a dental mannequin. After being bonded with brackets, the models were scanned, and the actual and designed positions of the brackets were compared. RESULTS: There was no immediate debonding. The orthodontists spent a significantly shorter time (22.36 minutes) in bracket bonding than the dental students (24.62 minutes; P < .05). The brackets tended to deviate to the buccal side in the dental student group. Linear deviations tended to be smallest in the orthodontic student group, but no significant difference was found among operators with different clinical experience (P > .5). All linear and angular deviations in each group were under 0.5 mm and 2°, respectively. CONCLUSIONS: Clinical experience was positively related to the bonding accuracy using GBDs, especially in the buccolingual dimension. Inexperience also led to longer bonding duration. However, bonding accuracy was clinically acceptable in general.

Evaluation of the accuracy of digital indirect bonding vs. conventional systems: a randomized clinical trial.

OBJECTIVES: To compare the accuracy and chair time of self-ligating brackets using direct bonding, traditional indirect bonding (IB), and computer-aided design/computer-aided manufacturing (CAD/CAM) IB techniques after orthodontic leveling and alignment. MATERIALS AND METHODS: Forty-five patients were randomly assigned to three bonding groups (G1 [n = 15], G2 [n = 15], and G3 [n = 15]). Evaluation after the alignment and leveling phases used two parameters of the objective grading system of the American Board of Orthodontics for root parallelism and posterior marginal ridges, assessed using panoramic radiographies (PR I and PR II), a digital model, and a plaster model. Blinding was only applied for outcome assessment. No serious harm was observed except for gingivitis associated with plaque accumulation. RESULTS: Although G3 showed better numerical results, they were not statistically significant in the radiographic or model evaluations (P > .001). Mean chair time was significantly shorter in G3 (1.1 ± 11.8 min) vs. G1 (56.7 ± 7.3 min) and G2 (52.8 ± 8.3 min; P < .001). CONCLUSIONS: The CAD/CAM IB system for self-ligating brackets was as effective as conventional methods, with a shorter chair time.

Is bracket bonding with guided bonding devices accurate enough for crowded dentition?

BACKGROUND: This research aimed to study whether bracket bonding using guided bonding devices (GBDs) is accurate enough for crowded dentitions in vitro. METHODS: Fifteen three-dimensionally (3D) printed resin model sets were included and divided into three groups: mild, moderate, and severe crowding. The resin models were scanned and virtually bonded with brackets. Corresponding GBDs were generated and 3D printed. Subsequently, the brackets were bonded to the resin models on a dental mannequin using the GBDs. The models with bonded brackets were scanned, and comparisons were made between the positions of the actually bonded and the planned ones to evaluate possible deviations. RESULTS: There was no immediate bonding failure in any group. The bonding duration tended to increase with crowding severity (P > 0.05). Almost all linear and angular deviations in all groups were below 0.5 mm and 2°, respectively, and no statistically significant difference was found among the different crowding degrees (P > 0.05). In all groups, the brackets tended to deviate lingually and had buccal crown torque. Brackets in the groups with mild and severe crowding showed a tendency for mesiobuccal rotation. CONCLUSION: GBDs provide high bracket bonding accuracy for dentitions with different crowding degrees and, thus, could hopefully be applied to uncrowded and crowded dentitions alike.

3D printed indirect bonding trays: transfer accuracy of bar vs shell design in a prospective, randomized clinical trial.

OBJECTIVES: To compare the transfer accuracy of two different indirect bonding (IDB) trays. MATERIALS AND METHODS: Digital IDB was performed on a total of 30 patients using one of two designs: shell and bar trays, with 15 patients in each group. Trays were designed with the Appliance Designer software (3Shape A/S, Copenhagen, Denmark). Angular (torque, tip, angulation) and linear (mesiodistal, buccolingual, occlusogingival) differences were compared between the bonded intraoral scans taken immediately after IDB and the virtually bracketed model prepared in Ortho Analyzer software (3Shape A/S) using open source GOM inspect software (GOM GmbH, Braunschweig, Germany). RESULTS: There were no significant differences found between the bar and shell groups. Within the groups, significant tip differences were found between the incisors, canines, and premolars in both groups (P = .0001). Additionally, a statistically significant torque difference was found in the canines and incisors in the shell group. The percentage of values that deviated from the clinical acceptance limit was relatively higher in the bar group. CONCLUSIONS: Although there was no statistical difference between groups, the shell tray showed better results according to clinical acceptability limits. This study is important as it is the first clinical study to compare directly printed transfer trays with different designs.

3D-printed indirect bonding trays and transfer jigs for lingual brackets: Digital workflows and two case reports.

With the advancement of 3-dimensionally (3D) printing technology, orthodontists can design and fabricate 3D-printed indirect bonding trays and transfer jigs for lingual brackets independently from the laboratory. The present article describes, in detail, the digital workflows for designing and fabricating 3D-printed lingual bracket indirect bonding trays and transfer jigs. Additionally, it aims to demonstrate the effectiveness of this approach in managing common orthodontic issues in adult patients. The first case report exemplifies the successful management of moderate crowding in a Class I adult patient using a non-extraction approach with lingual brackets and flexible 3D-printed indirect bonding trays. The second case illustrates the application of lingual brackets and rigid 3D-printed indirect bonding trays in managing a skeletal Class II adult patient with mouth protrusion requiring four-bicuspid extractions. The achieved good treatment results might demonstrate the high transfer accuracy of 3D-printed lingual bracket indirect bonding trays. Additional studies with large sample sizes should be conducted to compare the effectiveness and efficiency of 3D-printed trays with other tray types.

Bonding techniques in lingual orthodontics.

Bonding techniques in lingual orthodontics differ slightly from their counterparts in labial treatment, although there are many shared features. If protocols are followed correctly, bonding outcomes are very predictable and lingual bracket bonding can be integrated into a mixed orthodontic practice with the minimum of disruption. Here, we highlight the fundamentals of both chemical and light/dual cure bonding procedures using lingual appliances, and discuss special bonding circumstances. Although not exhaustive, this article will provide essential information for those operators embarking on the bonding of lingual appliances.