Background/objectives: When the indirect bonding technique was developed in 1972 by Silverman and Cohen, many authors wondered whether this technique would improve bracket positioning accuracy compared to the direct bonding technique. Studies have found little to no difference between them regarding positioning accuracy. Recently, technological advances have improved the indirect method by allowing the user to position the brackets virtually using software applications such as OrthoAnalyzer™. To the best of our knowledge, no studies have compared direct positioning to this new digital indirect technique. Thus, the aim of this study was to compare the accuracy of placement between the two techniques in the maxillary arch using two different bracket types: conventional twin brackets and self-ligating brackets. A secondary objective was to evaluate whether bracket type affected positioning accuracy. Methods: A maxillary arch of a patient was scanned by digital impression. Forty resin duplicates of this model were printed and then mounted on a mannequin head, on which 20 practitioners performed direct bonding using the aforementioned brackets. Later on, they performed a virtual indirect bonding of the same case virtually, with the digital impression superimposed to the patient’s CBCT (cone-beam computed tomography). Afterwards, the direct bonded models were unmounted, scanned, and then superimposed to the indirect models. Differences in height, angulation and mesio-distal position of the brackets were evaluated. Results: Regarding height, the differences between direct and indirect methods were not significant. Height difference was significantly greater for self-ligating brackets compared to conventional brackets. Regarding mesio-distal positioning, significant differences were noted for teeth 13 and 15 with self-ligating brackets (p-value = 0.019 and p-value = 0.043, respectively). The deviation was also greater for these brackets. Regarding angulation, the difference was significant on tooth 12 when using conventional brackets (p-value = 0.04) and on 12 and 22 when using self-ligating brackets (p-value = 0.09). Conclusion/implications: There were no major significant differences between direct and indirect bonding. Differences were significant only on the laterals for of angulation, and on teeth 13 and 15 for mesio-distal centering. The bracket type seems to influence positioning accuracy, since self-ligating brackets had a larger deviation range than conventional brackets.

Nicolas Nassar, Allahyar Geramy, Roland Kmeid, Nayla Bassil Nassif, Lina Medawar, Patrick Sayegh, Joseph Bouserhal. Korean J Orthod -0001;0:. https://doi.org/10.4041/kjod24.201

Objectives: This systematic review and meta-analysis aimed to evaluate microbial adhesion and biofilm formation on additively manufactured composite-based orthodontic clear aligners compared with thermoformed aligners and other conventional polymeric materials. The influence of material composition, surface roughness, post-processing parameters, and cleaning protocols on microbial colonization was also assessed. Methods: A comprehensive search of PubMed, EMBASE, Scopus, Web of Science, and the Cochrane Library was conducted up to September 2025. Only in vitro studies investigating microbial adhesion, biofilm biomass, or microbiome changes on three-dimensional (3D)-printed aligner composites were included. Primary outcomes consisted of colony-forming units (CFU), optical density (OD) from crystal violet assays, viable microbial counts, and surface roughness. Risk of bias was assessed using the RoBDEMAT tool. Data were narratively synthesized, and a random-effects meta-analysis was performed for comparable datasets. Results: Five studies fulfilled the inclusion criteria, of which two in vitro studies were eligible for meta-analysis. Microbial adhesion and biofilm accumulation were influenced by the manufacturing technique, composite resin formulation, and surface characteristics. Certain additively manufactured aligners exhibited smoother surfaces and reduced bacterial adhesion compared with thermoformed controls, whereas others with increased surface roughness showed higher biofilm accumulation. Incorporating bioactive additives such as chitosan nanoparticles reduced Streptococcus mutans biofilm formation without compromising material properties. The meta-analysis, based on two in vitro studies, demonstrated higher OD values for bacterial biofilm on 3D-printed aligners compared with thermoformed aligners, indicating increased biofilm biomass (p < 0.05), but not necessarily viable bacterial load. Conclusions: Microbial adhesion and biofilm formation on 3D-printed composite clear aligners are governed by resin composition, additive manufacturing parameters, post-curing processes, and surface finishing. Although certain 3D-printed materials display antibacterial potential, the limited number of studies restricts the generalizability of these findings. Clinical Significance: Optimizing composite formulations for 3D printing, alongside careful post-curing and surface finishing, may help reduce microbial colonization. Further research is required before translating these findings into definitive clinical recommendations for clear aligner therapy.

Objectives: This study aimed to analyze the three-dimensional displacement of maxillary first molars using a finite element model with two headgear configurations, namely cervical and horizontal pull headgears, as well as pendulum, infrazygomatic miniscrews, Bollard miniplates, Advanced Molar Distalization Appliance (AMDA), and Beneslider. The goal was to clarify how variations in anchorage design and force direction influence molar movement across the sagittal, vertical, and transverse planes. Methods: A three-dimensional finite element model of the maxillary dentition and supporting structures was constructed using reference anatomical data and standardized material properties. Each appliance was virtually simulated under its clinically recommended force magnitude and direction to ensure realistic biomechanical conditions. The orientation of each force vector relative to the molar’s center of resistance (CR) was analyzed, and resulting tooth displacements were quantified along the sagittal (Z), vertical (Y), and transverse (X) axes using 49-node reference paths connecting key anatomical landmarks. Results: Appliances applying forces through or above the molar CR, such as the AMDA, infrazygomatic miniscrews, and Bollard miniplates, produced nearly bodily distalization with minimal tipping (<0.6° (range 0.3–0.6°)) and slight intrusion (−0.12 to −0.18 mm). Conversely, systems delivering forces below the CR, such as the cervical headgear and pendulum, resulted in greater crown tipping and extrusion. The Beneslider exhibited an intermediate displacement pattern with moderate vertical control. Conclusions: Force vector height and direction relative to the molar CR critically determine 3D displacement behavior. Skeletal anchorage and adjustable systems, particularly the AMDA, demonstrated the most controlled distalization pattern with minimal tipping, whereas conventional tooth-borne designs induced more tipping and extrusion.

Objectives: This systematic review evaluated enamel surface alterations and residual composite following the removal of clear aligner attachments, with particular emphasis on the influence of removal techniques, instrument selection, operator experience, and the use of magnification on enamel preservation and cleaning efficiency. Methods: A comprehensive electronic search was performed in PubMed, Scopus, Embase, Web of Science, and Scielo up to October 2025. In vitro, ex vivo, and clinical studies assessing enamel loss, residual composite, surface roughness, or removal time after clear aligner attachment removal were included. Study selection, data extraction, and methodological assessment followed the PRISMA 2020 guidelines and Cochrane Handbook recommendations. Risk of bias was evaluated using a modified Joanna Briggs Institute checklist for laboratory-based studies. Due to substantial methodological heterogeneity, a narrative synthesis was conducted. Results: Of 656 identified records, three in vitro/ex vivo studies were assessed for eligibility. Reported enamel loss ranged from approximately 15 µm to more than 50 µm, depending on the removal protocol and visualization conditions. Residual composite covered approximately 20–40% of the treated enamel surface. Multi-step protocols combining tungsten carbide burs with silicone polishers under magnification demonstrated the most favorable balance between composite removal efficiency and enamel preservation. Fiberglass burs were associated with smoother enamel surfaces but increased enamel loss, whereas one-step polishing systems (OneGloss, Enhance, SM104) resulted in reduced surface roughness and shorter procedural time. The use of magnification loupes (≥2.5×) consistently improved removal precision and reduced residual composite. Meta-analysis was not feasible due to heterogeneity in outcome measures and testing methodologies. Overall risk of bias was deemed acceptable. Conclusions: Based on the limited number of available in vitro/ex vivo studies, removal of clear aligner attachments appears to be associated with measurable enamel loss and residual composite, largely influenced by the instruments and visualization aids used. Sequential carbide–silicone polishing protocols performed under magnification appear promising based on limited in vitro/ex vivo evidence, demonstrating a favorable balance between composite removal and enamel preservation under controlled laboratory conditions. However, given the scarcity of evidence and absence of clinical trials, these findings cannot be directly extrapolated to routine clinical practice. Further well-designed studies are required before definitive clinical recommendations can be established.