Search Results (92)

Objective: To evaluate the concordance of automated 3D superimposition methods applied to digital models, with a focus on methods that consider stable palatal regions as geometric reference landmarks versus those that do not. Design and setting: This was a prospective, cross-sectional study using digital model files of patients undergoing orthodontic treatment in a university clinical setting. Participants: Sixty-one patients were prospectively enrolled and divided into three groups based on the type of orthodontic treatment they received: (20) non-extractive orthodontic treatment without intermaxillary elastics, (21) intermaxillary elastics, and (20) control subjects with no orthodontic movement. The inclusion criteria included the availability of complete pre- and post-treatment digital casts and the absence of significant craniofacial anomalies. Methods: Three superimposition methods were tested: (1) superimposition according to palate and palatal ridges, (2) best-fit superimposition of arches in occlusion, and (3) best-fit superimposition of individual arches. Discrepancies were identified by comparing the spatial positions derived from each method. Within three spatial axes, deviations of ±0.5 mm and ±1.15° were not considered significant. Bland–Altman plots were used to quantify palatal rugae based and non-based spatial differences between methods. Differences in the superimposition results between the three patient groups were evaluated using ANOVA tests. Results: Differences in spatial position between the superimposition methods often exceeded the acceptable range. The results were compared between the three patient groups with a statistical significance of α = 0.05. In the present study, the high reliability of the superimposition method based on the palate and palatal ridges was observed. Conclusion: Superimposition methods based on the palate and palatal rugae provide superior accuracy in determining treatment-related changes in upper arch digital models. These findings illustrate the need for appropriate selection of superimposition techniques based on the study objective of using clinically relevant techniques. Full article

Background: Canine impaction complicates treatment and prolongs duration, requiring precise localization. CBCT is the gold standard for diagnosis and assessment. However, it involves high radiation exposure and cost. This study aimed to evaluate the effectiveness of a combined biomechanical approach for orthodontic traction of impacted maxillary canines (IMCs) and to determine whether intraoral scans (STL files) could replace a final CBCT in assessing canine repositioning. Methods: The sample included 10 patients (7 males and 3 females) with 13 severely displaced IMCs, treated with a protocol combining Invisalign^® aligners, elastics, mini-implants, and sectional wires. In all, 9 IMC were palatally impacted, while 4 were buccally impacted. A representative clinical case is presented to illustrate the biomechanics used in one of the complex cases. Canine movement was evaluated at the cusp and apex through two methods: overlay of pre- and post-treatment CBCTs, and overlay of initial and final STL scans onto the initial CBCT. Results: A Class I canine relationship was successfully achieved in all patients. No statistically significant differences were found between the two measurement methods (p > 0.05). Conclusions: Orthodontic traction of IMC, especially in complex cases, can be achieved using aligners, elastics, mini-implants, and sectional wires. Once the canine crown has erupted and is clinically visible, STL scans overlaid with the initial CBCT can accurately assess the final position of the crown and root. This allows clinicians to avoid a second CBCT in selected cases, reducing patient radiation exposure while maintaining diagnostic accuracy. Full article

Maintaining the cleanliness of orthodontic aligners is crucial for oral hygiene and preserving the optical properties of aligners. In this randomized clinical trial, we compared the effectiveness of different cleaning methods for the maintenance of Invisalign clear aligners. Twelve adult patients received five aligners, each worn for 10 days. The aligners were divided based on the cleaning method: tooth brushing with whitening toothpaste, vinegar, Fittydent Super Cleansing Tablets, Invisalign cleaning crystals, and only water. Scanning electron microscopy (SEM) was used to detect surface morphology changes; color changes (ΔE) were evaluated using a spectrophotometer. Fourier transform infrared spectroscopy (FTIR) with a diamond hemisphere was used to study the aligners’ chemical compositions. Nanoindentation testing was used to assess changes in the elastic modulus. SEM confirmed the effectiveness of Invisalign cleaning crystals in maintaining cleanliness, revealing a surface similar to that of the control group with no adverse effects. Color stability analysis revealed significant ΔE value differences; whitening toothpaste had significantly lower ΔE values than water and Invisalign cleaning crystals. The elastic modulus and FTIR analyses indicated no significant differences between the cleaning methods. Therefore, Invisalign cleaning crystals and whitening toothpaste are safe for aligner maintenance, showing successful and aesthetically pleasing results. Full article

According to the World Health Organization, malocclusion type III is third, most important oral health problem. It may be the least prevalent malocclusion, but it is the most noticeable and challenging for orthodontic therapy. With this narrative review, we wanted to give a summation of the most current knowledge about diagnostics, different therapy options, limitations, and additional factors that can influence the therapy of class III malocclusion to help clinicians and researchers focus on the specific approaches. Therapy options were divided into the following groups: orthopedic, orthodontic, and surgical. The SNA, SNB, and ANB angles (cephalometric values) are the best ones to examine improvements in different skeletal improvements, while dentoalveolar improvements were also described, emphasizing the limitation of orthopedic therapy to change the skeletal discrepancy. Eruption-guided appliances and chin cups are more effective in early childhood, mixed dentition, during permanent teeth eruption, with no significant skeletal discrepancy. If a discrepancy exists, a face mask is the first therapy choice. The therapy of an underdeveloped maxilla can be solved with different palate expanders. Bulkiness, lack of long-term results, and duration of therapy make fixed orthodontic appliances with braces and elastic traction favorable nowadays. If the skeletal discrepancy is major, a surgical approach should be considered. One of the main limitations in articles is the combination of different therapy approaches, ages, and dentition preferred for device application, duration of therapy, and lack of information about long-term outcomes. On the other hand, the lack of original articles is noticeable, so further research should be done. Full article

Background/Objectives: The growing demand for esthetic, less painful, and more comfortable orthodontic treatment has led to increasing use of aligner systems. Initially used for less complicated malocclusions, aligners are now being incorporated into complex treatment plans, including cases involving impacted teeth. While aligners are a popular alternative to traditional fixed appliances, they still have limitations. This study aims to evaluate the effectiveness of aligner-based orthodontic treatment in patients with impacted or significantly ectopic canines. Methods: This study was conducted in accordance with the PRISMA guidelines. The search terms used were as follows: ‘Clear Aligner’ OR ‘Invisalign’ AND ‘Impacted Canine’ OR ‘Impacted Tooth’ OR ‘Ectopic Tooth’ OR ‘Ectopic Canine.’ A total of 1101 records were identified, of which 170 articles underwent screening. Fifteen articles were assessed for eligibility, and ultimately six case reports and one three-dimensional finite element analysis (FEA) study were included for both quantitative and qualitative synthesis. Results: According to the studies, additional appliances are often required to achieve favorable outcomes when treating impacted canines with aligner systems. Temporary anchorage devices (TADs) were used in 5 out of 9 reported cases for canine traction into the dental arch. In three cases, TADs were combined with sectional wires implemented as cantilevers. Elastics were used in 6 out of 9 cases for traction to the opposite arch, and in 5 out of 9 cases as interarch elastics attached to the aligners. Interarch elastics were applied in various ways, either directly to the aligners or to primary canines using hidden buttons inside pontics or dovetail hooks. Elastics were also anchored to the lower arch with class II, class III, or cross-arch (criss-cross) mechanics. Conclusions: This review highlights the promising potential of aligner systems in the treatment of impacted canines. However, additional auxiliaries, such as TADs, sectional wires, or elastics remain nearly essential for initial canine traction. Aligner systems offer versatile treatment options, and the possibility of reduced treatment time represents a valuable area for future research. Full article

Background: This cephalometric study aimed to evaluate the effects of clear aligner therapy in growing individuals with Class II malocclusion, comparing two functional approaches: the use of Class II elastics or the Mandibular Advancement (MA). Methods: Cephalometric data from 39 patients with Class II malocclusion treated using clear aligners either combined with Class II elastics (EL group; n = 18) or Mandibular Advancement (MA group; n = 21) were analyzed and compared with an untreated control group (UC2; n = 15). Results: Both treatment groups (EL and MA) showed a significant reduction in the ANB angle compared to the control (MA: −1.5°; EL: −2.2°; UC2: +0.2°). An increase in mandibular length, as measured by Co–Gn, was observed in both the EL and MA groups (+5.5 mm and +8.3 mm, respectively) relative to the control group. Soft tissue analysis of the Pg–TVL distance from T1 to T2 revealed the most substantial forward displacement of the chin in the MA group (MA: +2.0 ± 3.7 mm; EL: +0.5 ± 0.7 mm; UC2: −1.6 ± 3.3 mm). Vertically, the MA group exhibited a more marked decrease in the palatal-mandibular plane angle than the other groups. Both treatment modalities significantly reduced overjet and overbite from T1 to T2. Conclusions: The EL and MA appliances effectively advanced the mandible, leading to significant improvements in the sagittal relationship, overjet, and overbite while maintaining stable vertical control. Additionally, the MA group exhibited a more pronounced forward movement of the soft tissue chin. Full article

Background: During the initiation of routine orthodontic treatment with fixed appliances, placing elastic separators (ESs) may lead to the patient experiencing considerable pain. Earlier studies evaluating the effects of low-level laser therapy (LLLT) on reducing pain caused by orthodontic ESs have reported contradictory results. The aim of our study was to evaluate the effect of a single application of LLLT on the experience of pain following ES placement. Methods: A double-blind, placebo-controlled randomized controlled trial was performed—with implementation of the split-mouth technique—where n = 33 volunteers (12 male and 21 female; aged between 19 and 36 years) were enrolled. ESs were placed at the mesial and distal surfaces of the first permanent molars in the upper or lower jaws. Jaws were divided into two quadrants; the treatment group received LLLT (using a GaAlAs diode laser, at a 980 nm wavelength, with 100 mW producing 6 J of energy; continuous wave), while the other quadrant served as the placebo side receiving a similar treatment, but without laser irradiation, immediately after separation. A questionnaire with a visual analogue scale (VAS; 0–100) was used for the assessment of pain (spontaneous pain and pain on mastication) scored for each first permanent molar directly after separation and after 6, 24, 48 and 72 h of both laser and placebo treatment application. Results: Mean VAS values were lower, but not significantly different, between the treatment vs. placebo groups for spontaneous pain at either measurement point (p > 0.05). Mean VAS values were significantly lower in the treatment groups for pain on mastication at the 6 (9.29 ± 12.65 vs. 19.07 ± 20.99; p = 0.025), 24 (21.96 ± 21.11 vs. 37.19 ± 26.35; p = 0.012) and 48 h (28.01 ± 21.40 vs. 42.60 ± 26.29; p = 0.016) measurement points. The analgetic effect of LLLT was most effective after 6 h, both in the resting position (−49% decrease) and during mastication (−51% decrease). Conclusions: A single application of LLLT with 6 J of energy may have beneficial effects on reducing the pain caused by orthodontic ESs used at the initiation of treatment with fixed appliances, especially during mastication, after 6–48 h following the separation procedure. Trial registration: clinicaltrials.gov ID NCT06816537 (date of registration: 7 February 2025, retrospectively registered). Full article

Aim: Class II Division I malocclusion poses significant challenges in orthodontics. The combination of a Herbst appliance and miniscrew anchorage emerged as a practical solution to improve skeletal and dental outcomes. This study employed finite element analysis to evaluate the biomechanical effects of a miniscrew-supported Herbst appliance on mandibular advancement and dentition movement. Methods: High-definition CBCT scans captured the maxilla and mandible’s detailed dental anatomy. The scans were stored in DICOM format for seamless integration with Mimics software (Mimics Innovation Suite research version 21.0, Materialise NV, Leuven, Belgium) for 3D reconstruction and model refinement. The appliance, designed with a maxillary fixed palatal arch and mandibular acrylic splint connected by telescoping rods, incorporated titanium TADs and elastic chains. STL models were optimized in Geomagic x Design for finite element analysis in Abaqus, assigning validated mechanical properties for materials. Tetrahedral meshing and realistic boundary conditions simulated biomechanical interactions. Tetrahedral C3D4 elements were used for meshing, ensuring a balance between computational efficiency and detailed anatomical representation. Tetrahedral meshing and realistic boundary conditions simulated biomechanical interactions. Dynamic simulations in CATIA evaluated mandibular movement. FEA analyzed displacement across dentoalveolar structures along the X, Y, and Z axes to assess treatment efficacy and biomechanical stability. Results: The Z displacement analysis revealed that the incisal edges of the lower central, lateral, and canines shifted lingually by 0.41, 0.4, and 0.47 mm, respectively. Additionally, the apices of the lower central, lateral, and canines displaced backwards by 0.05 mm, 0.05 mm, and 0.07 mm, respectively. Conclusions: The appliance facilitated mandibular advancement, bodily retracted the lower incisors, well-controlled the upper ones, and mesial-tipped the upper posterior teeth. In contrast with traditional functional appliances, it caused the lower anterior teeth to move backwards, while skeletal anchorage overcame some shortcomings of nonsurgical treatments. This method might be a good treatment option for growing skeletal Class II patients. Full article

To create an orthodontic bracket material combining the favourable properties of ceramic and polymer while minimising their limitations, graded porous ceramic scaffolds were created using unidirectional gelation-freeze casting, following which the pores were infiltrated with polymer. Two processing parameters were investigated: (1) sedimentation times of 0, 8, and 24 h, with ceramic solid loading of 20 vol.% and 2.5 wt.% gelatine concentration, and (2) ceramic solid loadings of 15, 20, and 25 vol.% with a fixed 2.5 wt.% gelatine concentration and an 8 h sedimentation time. The graded ceramic structures demonstrated porosity gradients ranging from 9.86 to 63.84 vol.%, except those with 25 vol.% ceramic solid loading at 8 h sedimentation. The Al₂O₃-UDMA/TEGDMA composites had compressive strengths of 60.25 to 120.92 MPa, modulus of elasticity of 19.84 to 35.29 GPa, and fracture toughness of 0.78 to 1.78 MPa·m^1/2. The values observed were between those of dense ceramic and pure polymer. Statistical analysis was conducted using Excel^® 2019 (Microsoft^®, Washington, DC, USA). Means, standard deviations, and 95% confidence intervals (CI) were calculated at a significance level of α = 0.05, alongside polynomial regression to evaluate relationships between variables. Composites with 20 vol.% ceramic solid loading at 8 h sedimentation displayed promising potential for further clinical validation. Full article

Background/Objectives: Delayed tooth eruption (DTE) is a very challenging clinical situation, and the pathogenesis has been associated with local, systemic, and genetic factors. The aim of this presentation is to describe the management of such a case with delayed eruption of mandibular central incisors and canines. Methods: An 11-year-old female patient presented with DTE involving lower incisors (32, 42) and canines, seeking orthodontic treatment. Furthermore, lower permanent central incisors were congenitally missing while lower deciduous incisors were still in place. After a year-and-a-half of just monitoring the case and having suggested the extraction of deciduous first molars and canines, orthodontic treatment started with fixed appliances in the upper and lower jaw. First and second premolars gradually erupted after the precursor’s extraction. Lower canines and the two existing incisors were, after several months, surgically exposed and a gold chain apparatus was bonded on each one, while the closed eruption technique was chosen. A 0.17 × 0.25 stainless steel (SS) lingual wire, leaning on the buccal tubes of the lower molar bands and properly manipulated around them, was fitted in conjunction with the labial brackets and wires in order to facilitate the traction of the impacted teeth, which was carried out for one after the other using either an elastic chain or a second super-elastic wire. Results: All impacted teeth were finally restored to their proper place. The root of 71 did not present resorption, so the tooth was maintained in the lower arch while inter-proximal reduction was performed in the upper arch in the anterior region, in order to anticipate the lower missing incisor. Finally, a stable occlusion with proper contacts was achieved. Conclusions: Proper diagnosis, on-time extractions of deciduous teeth, and a well-designed treatment plan regarding space management and orthodontic traction of impacted teeth contributed to successful treatment outcomes in this DTE case. Full article

Metal alloys continue to be, and are expected to remain, essential materials for fabricating prosthetic elements due to their unique properties, particularly their high strength, durability, and appropriate modulus of elasticity, which make them well-suited for such applications. However, commonly used non-precious metal alloys exhibit lower corrosion resistance compared to precious metal alloys. This reduced resistance leads to the release of metal ions from the alloy into the oral environment. Adverse biological responses to metal alloys can be mitigated through various surface modifications, most commonly by applying coatings. These coatings are typically ceramic, including oxides, nitrides, and carbides. In this study, the mechanical properties (hardness, modulus of elasticity, adhesion, and thickness) of complex Si(C,N) coatings applied to a prosthetic Ni-Cr alloy were investigated. Depending on the proportions of N, C, and Si in the coating, the hardness ranged from 12 to 15 GPa, while the modulus of elasticity varied between 130 and 170 GPa. Adhesion strength, measured via the scratch test method, was within an acceptable range. Microscopic analysis revealed that the coatings had a thickness of 2 to 2.5 μm, exhibiting a homogeneous, columnar structure. In conclusion, the properties of the fabricated Si(C,N) coatings are deemed satisfactory for their intended use as protective layers for prosthetic and orthodontic components. Full article

The quad-helix and W-arch are commonly used appliances for expanding the dental arch in orthodontic treatment. However, differences in performance between these two expanders remain unclear, and no guidelines exist for selecting one over the other. The purpose of this study was to investigate whether there were differences in dental arch expanding ability between these appliances. Maxillary arch expansions were simulated using the finite element method. The expander was assumed to be an elastic beam, while the teeth and alveolar bone were treated as rigid bodies. The periodontal ligament (PDL) was modeled as a nonlinear elastic material. The teeth moved in the same direction as the initial movement caused by the elastic deformation of the PDL. The right and left canines, premolars, and first molars were expanded symmetrically in either parallel or fan shapes. When the wire diameter of the W-arch was set to 0.032 inches its stiffness became equivalent to that of a quad-helix with a wire diameter of 0.036 inches. Canines and premolars were expanded through tipping movements. The molars initially tipped buccally, then became upright and moved bodily. Both expanders expanded the arch in almost the same manner. There was no difference in arch expansion ability between the W-arch made of 0.032-inch wire and the quad-helix made of 0.036-inch wire. The W-arch may be preferred as the first choice due to its simpler structure compared to the quad-helix. Full article

Background/Objectives: Molar distalization with clear aligners is increasingly used for Class II malocclusions, yet the associated periodontal ligament (PDL) stress and potential root resorption risk remain unclear. Three-dimensional finite element analysis (3D FEA) provides insight into these factors, but variations in attachments and anchorage strategies merit systematic evaluation. To determine whether molar distalization with clear aligners exceeds the PDL stress thresholds for root resorption and to assess how different attachments and anchorage methods influence stress distribution. Methods: In accordance with the PRISMA 2020 guidelines, four electronic databases were searched without language or date restrictions. Studies were included if they (1) employed 3D FEA, (2) analyzed PDL stress during aligner-based molar distalization, and (3) assessed root resorption risk or stress thresholds. Two reviewers independently screened and extracted data, yielding eight studies. Results: Attachments lowered PDL stress and distributed forces more evenly, reducing root resorption risk compared with no attachment cases. Micro-implants shifted stress to molars and protected anterior teeth; palatal mini-screws achieved greater distalization but higher stress, requiring caution, while buccal mini-screws showed lower stress in first premolar roots. Placing a mini-screw between first and second molars yielded the lowest, most uniform stress. Class II elastics—with precision cuts—demonstrated low compressive stress and improved anchorage, although some resorption risk persisted in maxillary anteriors. Conclusions: Clear aligner–based molar distalization can elevate PDL stress to potentially resorptive levels. Although attachments, micro-implants, and Class II elastics improve stress distribution and lessen root resorption risk, it is not fully eliminated. Careful, individualized treatment planning remains essential, and further clinical validation is needed to establish definitive guidelines. Full article

This study evaluated the effect of oral cavity environmental factors on the friction and wear of materials used in 3D-printed orthodontic devices. Commercial materials GR-10 (Pro3Dure) and NextDent SG (NextDent) were examined, with samples produced using ASIGA UV MAX and Phrozen Shuffle Lite 3D printers. Our tests included measurements of hardness, stiffness, elastic modulus, cyclic loading, scratch resistance, and tribological assessments in oscillatory motion. Surface analyses were conducted using scanning electron microscopy with an energy-dispersive spectroscopy analyzer. The results showed that NextDent SG exhibited higher hardness and modulus of elasticity, while GR-10 demonstrated better scratch resistance. Despite similar friction coefficients, significant variations in wear were observed under different environmental conditions, highlighting the importance of considering these factors in the performance of orthodontic materials. Full article

Background and Objectives: This study aimed to evaluate the outcomes of Class II subdivision teenage patients treated with Invisalign^® clear aligners (CAs) and elastics. Materials and Methods: A total of 23 individuals aged 14.3 ± 2.5 years were enrolled in this study. The participants were divided into Group 1 (mandibular midline deviation) and Group 2 (maxillary midline deviation). The midline deviation from the facial midline; anteroposterior discrepancy; overjet (OJ), overbite (OB), and Peer Assessment Rating (PAR) scores; upper incisor and lower incisor (L1) positions; and angulation were measured at the beginning (T0) and end (T1) of the orthodontic treatment. Results: Group 1 showed significant higher variations in OJ (−2.3 ± 2.3 vs. −0.6 ± 0.8, p < 0.001), OB (−2.1 ± 2.3 vs. −1.1 ± 1.4, p < 0.001), PAR score (−32.0 ± 11.7 vs. −27.3 ± 13.1, p < 0.001), L1-to-mandibular-plane angle (−3.6 ± 7.0 vs. −1.3 ± 3.2, p < 0.001), and interincisal angle (10.07 ± 8.7 vs. 5.9 ± 5.3, p = 0.007). The midline deviation was the only measurement with higher variation in Group 2. The average distance between the mesiobuccal cusp of the maxillary first molar and the buccal groove of the mandibular first molar was 0.3 ± 0.5 mm. Conclusions: A total of 21 patients achieved bilateral Class I (91% success rate) and demonstrated great improvement (72–96%) in PAR scores. Regardless of the etiology of malocclusion, the orthodontic correction of the Class II subdivision with CAs showed high accuracy and predictable results. Full article