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.

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.

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).

Colagem Indireta Virtual 3D: uma nova perspectiva para os protocolos de colagens indiretas / 3D Virtual Indirect Bonding: a new perspective for indirect bonding protocols

O propósito do tratamento ortodôntico é alcançar os objetivos estéticos e funcionais com eficiência. O posicionamento correto dos acessórios ortodônticos, como braquetes e tubos, constitui uma etapa crítica para se atingir esses objetivos, principalmente com os braquetes straight-wire, que devem ser colados o mais corretamente possível, minimizando recolagens e dobras de refinamento. Para suprir a dificuldade da colagem direta, que apresenta obstáculos como a presença de saliva, dificuldade dos pacientes na abertura bucal e diferenças anatômicas entre os dentes, um método de colagem indireta de braquetes foi proposto em 1972. Mais recentemente, com os avanços do escaneamento intraoral, planejamento virtual e impressão 3D, o método de colagem indireta de braquetes foi facilitado, apoiado pela tecnologia no posicionamento desses acessórios, minimizando a etapa laboratorial. Com a incorporação da tecnologia CAD/CAM ao método de colagem indireta, surgiu a colagem indireta virtual 3D, facilitando as etapas de todo o processo, unindo eficácia e eficiência a um protocolo clínico simples, trazendo novas perspectivas ao método de colagem indireta (AU)

The aim of orthodontic treatment is to achieve aesthetic and functional goals efficiently. The correct positioning of orthodontic accessories, such as brackets and tubes, is a critical step in achieving these objectives, especially with straight-wire brackets, which must be bonded as correctly as possible, minimizing re-bonding and refinement bends. To overcome the difficulty of direct bonding, which presents obstacles such as the presence of saliva, patients' difficulty opening their mouths and anatomical differences between teeth, a method of indirect bracket bonding was proposed in 1972. More recently, with advances in intraoral scanning, virtual planning and 3D printing, the indirect bracket bonding method was improved, supported by technology in the positioning of these accessories, minimizing the laboratory stage. With the incorporation of CAD/CAM technology into the indirect bonding method, 3D virtual indirect bonding emerged, facilitating the steps of the entire process, combining effectiveness and efficiency with a simple clinical protocol, bringing new perspectives to the indirect bonding method. (AU)

Youtube videos as a source of information on digital indirect bonding: A content analysis.

Purpose: The aim of this study was to evaluate YouTube videos as a source of information for digital indirect bonding techniques. Materials and methods: The keyword "digital indirect bonding" was first searched on YouTube, resulting in 57 recorded videos. Descriptive parameters, including source, target audience, purpose, duration, upload date, number of likes, dislikes, views, and comments, were then evaluated. After this initial assessment, the interaction index and viewing rate were calculated. Video content quality was determined using a 5-point scale that categorized videos as having poor, moderate, or good content quality. This rating was based on the presence and discussion of various topics related to digital indirect bonding, including digital scan, digital bracket placement, transfer tray production from a 3D-printed model or direct production as a 3D-printed tray, clinical application, and advantages and/or disadvantages. The videos were assessed for quality using the global quality scale (GQS) and video information and quality index (VIQI). Statistical evaluation was conducted using Kruskal-Wallis, Chi-square, and Pearson correlation analysis, and intraclass correlation coefficients were calculated to determine the rating reliability. Results: The majority of the videos were classified as having poor content quality (41.9%), followed by moderate (38.7%) and good (19.4%) content quality. No significant differences were found between the videos in terms of descriptive parameters. However, videos with good content quality had significantly higher GQS and VIQI scores than moderate and poor content videos. The total content showed significant correlations with GQS and VIQI (r=0.780 and r=0.446, respectively; plt;0.05). Conclusion: In conclusion, while the majority of YouTube videos regarding digital indirect bonding were of poor content quality, those that were of good content quality could be considered a useful source of professional information.

The Influence of Indirect Bonding Technique on Adhesion of Orthodontic Brackets and Post-Debonding Enamel Integrity-An In Vitro Study.

The increasing demand for orthodontic treatments due to the high prevalence of malocclusion has inspired clinicians and material scientists to investigate innovative, more effective, and precise bonding methods with reduced chairside time. This study aimed at comparing the shear bond strength (SBS) of metal and ceramic brackets bonded to enamel using the indirect bonding technique (IDB). Victory Series metal brackets (Metal-OPC, Metal-APC) and Clarity™ Advanced ceramic brackets (Ceramic-OPC) (3M Unitek, Monrovia, CA, USA) were bonded indirectly to extracted human premolars through the etch-and-rinse technique. A qualitative assessment of the enamel surface using microscopic methods was performed, and the amount of residual adhesive was reported as per the adhesive remnant index (ARI). Moreover, the bracket surface was evaluated with SEM-EDS. The highest SBS mean values were observed in the Ceramic-OPC group (16.33 ± 2.01 MPa), while the lowest ones were obtained with the Metal-OPC group (11.51 ± 1.40 MPa). The differences between the Metal-AOPC vs. Metal-APC groups (p = 0.0002) and the Metal-OPC vs. Ceramic-OPC groups (p = 0.0000) were statistically significant. Although the Ceramic-OPC brackets bonded indirectly to the enamel surface achieved the highest SBS, the enamel damage was significantly higher compared to that of the other groups. Thus, considering the relatively high bond SBS and favourable debonding pattern, Metal-APC brackets bonded indirectly may represent the best choice.

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.

Evaluation of effectiveness and efficiency of fixed orthodontic treatment comparing standard and computer-aided design and manufacturing conventional bracket systems using indirect bonding for both: A retrospective study.

BACKGROUND: To compare the effectiveness and efficiency of orthodontic treatment (OT) with standard versus computer-aided design and computer-aided manufacturing (CAD/CAM) indirect bonding of conventional brackets. METHODS: This retrospective study examined two groups: standard indirect bonding group (12 males, 13 females; mean age 12.21 ± 0.52 years), and digital indirect bonding group (11 males, 14 females; mean age 12.76 ± 1.32 years), treated via a CAD/CAM indirect bonding system. Conventional brackets were used in both groups. Pretreatment and post-treatment records were acquired for all subjects. Weighted Peer Assessment Rating (W-PAR) index was used to assess the effectiveness of OT, in conjunction with five angular cephalometric measurements (ANB°, Sn-GoGn°, U1-PP°, IMPA° and FMA°) and comparatively analyzed using generalized mixed-effects models and post hoc test. Treatment efficiency was assessed in terms of the numbers of bracket repositionings, archwire bends, accidental bracket debondings, appointments and treatment months. Comparative analysis of efficiency was performed using the asymptotic Wilcoxon-Mann-Witney test. Statistical significance was set at 5%. RESULTS: Total W-PAR and W-PAR component scores decreased significantly during treatment for both groups and in a similar way. Cephalometric measures ANB° and IMPA° significantly decreased and increased, respectively. Significantly fewer bracket repositionings, number of appointments and treatment months were recorded in group digital indirect bonding. CONCLUSIONS: Although both methods investigated were effective to achieve good outcomes, CAD/CAM indirect bonding method increased the efficiency of OT, when conventional brackets are used.

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.

MH-SETUP, combining Kesling wax-setup with indirect bonding and custom-made brackets for labial/lingual techniques to eliminate the finishing phase.

OBJECTIVE: A novel technique, named the MH setup (MH is an abbreviation for the author's name), was developed to provide an accurate yet simplified method to produce custom-made brackets without bonding errors. This setup aimed to simplify the treatment and eliminate the finishing phase, so that the orthodontist was able to provide better care with less time and lower costs. MATERIALS AND METHODS: The setup was performed in two major steps: direct bonding on the cast followed by cutting and setting the teeth into precise positions using brackets. The first set of brackets, bonded directly onto casts, oriented the teeth by setting them ideally into wax rims with full control over first-, second-, and third-order bends. The fully engaged archwire used allowed for precise control over the arch symmetry and form. Setting teeth in wax allowed the clinician to refine the occlusion and correct any minor errors that arose during the initial bonding. The second set of brackets, mounted on the fully engaged archwire, featured custom-made composite bases. The transfer tray combined the benefits of its soft inner and hard outer layers, providing control over bonding and later ease of peeling from the brackets. RESULTS: The patient was satisfied with a full bonding procedure lasting 15 min that remained simple without unnecessary stress. The clinician was confident that the procedure allowed the precise positioning of brackets and simple bonding for all teeth in the arch, combined with the elimination of the finishing phase. CONCLUSION: The MH technique offered a simple, precise, and inexpensive improvement to the Kesling wax setup. The process allowed for precise bonding without errors or expensive armamentarium. The brackets were transformed into custom-made prescriptions and could be used with labial or lingual techniques. The method allowed for teeth addition, trimming, or overcorrection according to the clinician's preferences. The MH setup facilitated visualization of the treatment objectives with precise locations and the opportunity to revise the treatment plan or to discuss further options with the patient.

Comparison of residual monomer amounts released from indirect bonding adhesives.

OBJECTIVES: To quantify the amount of residual monomer released from orthodontic adhesives used in the indirect bonding technique and compare it to a direct bonding composite resin. MATERIALS AND METHODS: Five hundred stainless steel orthodontic brackets were bonded on bovine incisors using five groups of bonding resins: Transbond XT (TXT), Transbond Supreme LV (SLV), Sondhi Rapid-Set (SRS), Transbond IDB (IDB), and Custom I.Q. (CIQ). Liquid samples were gathered on the first, seventh, 21st, and 35th days. Residual monomer release was measured from the liquid samples with a liquid chromatography device. In addition, the amount and shape of the adhesive between the tooth surface and the bracket base was evaluated using obtained electron microscopy images. The data were analyzed using analysis of variance, and a Tukey post-hoc test was applied. RESULTS: Hydroxyethylmethacrylate and bisphenol A-glycidyl methacrylate monomers were released by all study groups. Urethane-dimethacrylate was released from the TXT, SLV, IDB, and CIQ groups. Triethylene glycol dimethacrylate was released from TXT, SLV, IDB, and SRS groups. The amount of total monomer release was higher in chemically cured adhesives than in light-cured adhesives. Among the chemically cured adhesives, premix adhesives had the highest amount of total monomer release. The light-cured adhesives had less thickness. CONCLUSIONS: Light-curing adhesives have significantly less monomer release than chemically polymerized adhesives.

Transfer Accuracy of Three Indirect Bonding Trays: An In Vitro Study with 3D Scanned Models.

Objective: The goal of the current study is to compare the transfer accuracy of two different conventional indirect bonding trays with 3D-printed trays. Methods: Twenty-two patients' upper dental models were duplicated, scanned and brackets were bonded digitally. Different indirect bonding trays (double vacuum formed, transparent silicone and 3D-printed) were prepared according to three groups. These trays were used for the transfer of the brackets to the patients' models, then models with brackets were scanned. GOM Inspect software was used for the superimposition of virtual bracket setups and models with brackets. A total of 788 brackets and tubes were analyzed. Transfer accuracies were determined according to the clinical limit of 0.5 mm for linear and 2° for angular measurements. Results: 3D-printed trays had significantly lower linear deviation values than other trays for all planes (p<0.05). 3D-printed trays have significantly lower torque and tip deviation values than other groups (p<0.05). Transfer deviations were within the clinically acceptable limit for all transfer trays in horizontal, vertical and transverse planes. Deviation values of the molars were higher than those of the other tooth groups for all trays in the horizontal and vertical planes (p<0.05). Brackets were generally deviated toward the buccal direction in all tray groups. Conclusion: The transfer accuracy of 3D-printed transfer trays was more successful than the double vacuum formed and transparent silicone trays in the indirect bonding technique procedure. Deviations in the molar group were greater than those in the other tooth groups for all transfer trays.

Comparison of bracket bonding between two CAD/CAM guided bonding devices: GBD-U vs GBD-B.

OBJECTIVE: To compare the bracket bonding accuracy, efficiency, reproducibility, and three-dimensional (3D) printing duration of the computer-aided design/computer-aided manufacturing (CAD/CAM) unilateral contact guided bonding device (GBD-U) and the bilateral contact guided bonding device (GBD-B) in vitro. METHODS: Five resin dental model sets were scanned and virtually bonded with brackets. GBD-U and GBD-B were designed and 3D printed for each model. GBD-Us had guide blocks that fit the occlusal sides of the bracket tie-wings, while GBD-Bs had guide arms that fit the occlusal and distal sides of the tie-wings. Five orthodontic residents were recruited to bond brackets on the same 3D-printed copies of resin models in a dental mannequin using GBD-Us and GBD-Bs, respectively. The time for 3D printing of GBDs and bracket bonding was recorded. The linear and angular deviations between the bonded brackets and the virtually bonded ones were measured. RESULTS: A total of 50 sets of resin models (1000 brackets/tubes) were bonded. The time for 3D printing and bracket bonding was shorter for GBD-Us (41.96 mins/6.38 mins) than for GBD-Bs (78.04 mins/7.20 mins). In both devices, 100% linear deviations and over 95% angular deviations were below 0.5 mm or 2°, respectively. Deviations in the mesiodistal dimension, torque, angulation, and rotation were significantly lower in the GBD-U group (P<0.01). High inter-operator reproducibility of bracket bonding was confirmed for both devices. CONCLUSION: GBD-U was more time-efficient in 3D printing. Both GBDs showed clinically acceptable accuracy, whereas GBD-U had higher bonding accuracy in the mesiodistal dimension, torque, angulation, and rotation than GBD-B. CLINICAL SIGNIFICANCE: CAD/CAM GBD-U provides high bracket bonding accuracy in a time-efficient manner and has the potential to be clinically applied.

Impact of different pretreatments and attachment materials on shear bond strength of indirectly bonded brackets using CAD/CAM transfer trays to monolithic zirconia.

OBJECTIVE: Investigating the impact of different pretreatment methods, attachment materials and aging regimens on shear bond strength (SBS) between zirconia and indirectly bonded brackets using CAD/CAM transfer trays. METHODS: Zirconia substrates were conditioned with silica coated alumina (CoJet) and a) Clearfil Ceramic Primer Plus (CF), b) RelyX Ceramic Primer (RXP), c) Futurabond U (FU). Brackets were virtually placed, transfer tray designed (OnyxCeph) and 3D-printed for indirect bonding with a) Transbond LV (TBL), b) Nexus NX3 (NX3), c) Maximum Cure (MC). SBS testing was performed with a universal testing machine after 24 h, 500 thermal cycles, 90 d. Directly bonded brackets to human enamel using Transbond XT Adhesive served as control. The adhesive remnant index (ARI) was evaluated. Data was analyzed with Shapiro-Wilk, Kruskal-Wallis and Dunn's post-hoc test with Bonferroni correction, Chi2 test (p < 0.05), and the Weibull modulus was calculated. RESULTS: SBS ranged from 0.1 to 15.5 MPa and were influenced mostly by the attachment material. NX3 generally showed the highest values (9.5-15.8 MPa). Initially RXP/TBL and FU/TBL presented the lowest values (4.3/4.8 MPa). Aging regimens reduced SBS of MC irrespective of pretreatment, after 90 d values ranged from 0.1 to 0.9 MPa. ARI 1 was predominant in all MC groups and FU/NX3, 2 and 3 in the other groups. Weibull moduli ranged between 0.15 (MC/RXP/500 TC) and 6.24 (NX3/RXP/500 TC). SIGNIFICANCE: MC seems not to be suitable for indirect bonding using CAD/CAM transfer trays to zirconia. NX3 showed similar SBS values compared to the control, TBL lower.

A new method for successful indirect bonding in relation to bond strength.

The aim of the work was to develop a new transfer method for indirect bonding of brackets to improve the bond strength by applying a uniform contact pressure over the entire dental arch. This has a great potential to reduce the bracket loss rate during clinical treatment. A suitable shape memory polymer (SMP) was selected and prepared in the chemistry laboratory. This SMP applies a force to the brackets during bonding and thus increases the bond strength by applying uniform contact pressure. Various transfer trays were equipped with SMP platelets and the transfer of brackets from the plaster model to the real human tooth model was performed in vitro. The transfer accuracy and bond strength of the bonded brackets were investigated by 3D-overlay and shear tests, respectively. The transfer accuracy was technique sensitive and showed higher accuracy for the trays with SMPs and self-curing silicones than for the vacuum formed trays with SMPs. The bond strength of the indirectly bonded brackets with SMPs was on average 1-2 MPa higher than the bond strength of the brackets indirectly bonded with a conventional two-layer vacuum formed tray without SMPs. Thus, transfer trays with SMPs can provide a significant improvement in bond strength during indirect bonding after appropriate adjustment.

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.

Indirect bonding: an in-vitro comparison of a Polyjet printed versus a conventional silicone transfer tray.

OBJECTIVES: To investigate and compare transfer accuracy between a Polyjet printed indirect bonding (IDB) tray (SureSmile, Dentsply Sirona, Richardson, TX, USA) and a conventional two-layered silicone tray. MATERIALS AND METHODS: Plaster models of 24 patients were digitized with an intraoral scanner, and brackets and tubes were positioned virtually on the provider's homepage. IDB trays were designed over the planned attachments and Polyjet 3D-printed. For the conventional tray, brackets and tubes were bonded in their ideal positions manually before fabricating a two-layered silicone tray. For both trays, attachments were transferred indirectly to corresponding models. A second scan was performed of each bonded model to capture actual attachment positions, which were then compared to initial bracket positions using Geomagic Control (3D Systems Inc., Rock Hill, SC, USA). Linear and angular deviations were evaluated for each attachment within a clinically acceptable range of ≤0.2 mm and 1°. A descriptive statistical analysis and a mixed model were executed. RESULTS: Both trays showed highest accuracy in the orobuccal direction (99.5% for the 3D-printed tray and 100% for the conventional tray). For the 3D-printed tray, most frequent deviations were found for torque (15.4%) and, for the silicone tray, for rotation (1.9%). A significant difference was observed for angular measurements (P = .004) between the trays. CONCLUSIONS: Transfer accuracy of Polyjet printed IDB tray is not as high as transfer accuracy of the conventional silicone tray, though both trays show good results and are suitable for clinical application.

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.

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.

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.