Search Results (59)

Study design: Trends in the utilization of Mandibulo-Maxillary Fixation (MMF) are shifting nowadays from tooth-borne devices over specialized screws to hybrid MMF devices. Hybrid MMF devices come in self-made Erich arch bar modifications and commercial hybrid MMF systems (CHMMFSs). Objective: We survey the available technical/clinical data. Hypothetically, the risk of tooth root damage by transalveolar screws is diminished by a targeting function of the screw holes/slots. Methods: We utilize a literature review and graphic displays to disclose parallels and dissimilarities in design and functionality with an in-depth look at the targeting properties. Results: Self-made hybrid arch bars have limitations to meet low-risk interradicular screw insertion sites. Technical/clinical information on CHMMFSs is unevenly distributed in favor of the SMARTLock System: positive outcome variables are increased speed of application/removal, the possibility to eliminate wiring and stick injuries and screw fixation with standoff of the embodiment along the attached gingiva. Inferred from the SMARTLock System, all four CHMMFs possess potential to effectively prevent tooth root injuries but are subject to their design features and targeting with the screw-receiving holes. The height profile and geometry shape of a CHMMFS may restrict three-dimensional spatial orientation and reach during placement. To bridge between interradicular spaces and tooth equators, where hooks or tie-up-cleats for intermaxillary cerclages should be ideally positioned under biomechanical aspects, can be problematic. The movability of their screw-receiving holes according to all six degrees of freedom differs. Conclusion: CHMMFSs allow simple immobilization of facial fractures involving dental occlusion. The performance in avoiding tooth root damage is a matter of design subtleties. Full article

This systematic review analyzed the combined use of aligners and orthodontic temporary anchorage devices (TADs) in orthodontic treatment. The aim was to evaluate the effectiveness, benefits, and potential challenges of integrating the use of miniscrews with aligners. This review was conducted according to the PRISMA statement, and the protocol was registered at PROSPERO under the ID CRD42024576712. A comprehensive search on PubMed, Scopus, and Web of Science was conducted to identify relevant papers involving patients treated with aligners and TADs, dating from 1 January 2004 to 17 July 2024. The electronic database search identified a total of 458 articles. After eligibility, 14 records were selected for qualitative analysis. The findings suggest that the combination of aligners and miniscrews significantly enhances treatment precision and control, especially in cases requiring complex tooth movements, such as intrusion, extrusion, and distalization. The use of miniscrews allows greater control of movement and stability. The integration of these two techniques presents challenges, such as the need for precise miniscrew placement and potential discomfort during insertion. However, there was high satisfaction due to the aesthetic and comfort benefits of aligners. Further research is desirable to delve deeper into the topic to optimize clinical outcomes. Full article

Background/Objectives: Orthodontic temporary anchorage devices (TADs) in the lateral maxillary region are useful tools for successful orthodontic treatment. Radiological anatomical knowledge is crucial for the successful placement of TADs. The use of cone-beam computed tomography (CBCT) is essential for evaluating the relationship between the ideal placement point (IPP) and dental structures, particularly in cases with anatomical limitations. Accordingly, this study aims to assess the anatomical conditions for orthodontic mini-implant (MI) insertion in the posterior maxilla using CBCT as the gold standard. Methods: This retrospective study included 62 patients (37.1% male, 62.9% female) aged 11 to 50 years. CBCT scans (sagittal and axial cross-sections) were used to evaluate interdental bone characteristics in different regions. The evaluated regions were defined as follows: Region 1 (canine and first premolar), Region 2 (first and second premolars), Region 3 (second premolar and first molar), and Region 4 (first and second molars). All parameters were assessed at three predefined levels: A, B, and C, located 4, 3, and 2 mm, respectively, from the alveolar crest. At the aforementioned levels, we performed measurements, such as the interdental width (IDW) in the mesiodistal direction and buccopalatal depth (BPD). The last observation was the relationship between the ideal TAD placement point (IPP) and dental structures, such as contact points (CPs) and cusp tips (C1-cusp of mesial tooth, C2-cusp of distal tooth, in each region). Results: A statistically significant positive correlation was found between the IDW and BPD at Levels A, B, and C in Region 1, while a negative correlation was observed between the IDW and BPD at Level C in Region 2′. The highest percentages of IDW exceeding 3 mm were found in Region 4 at Level A (67.7%), followed by Region 1′ and 2′, both at Level A. The mean interdental width measured at each level on the right and left sides was highest at Level A, exceeding 3 mm, and the width decreased with each successive level. The mean BPD measured at each level on the right and left sides was also highest at Level A. Conclusions: This methodological approach could assist in ensuring precise and efficient implant insertion. Furthermore, it can be concluded that the safe zone for buccal and interdental mini-implant placement is located 4 mm from the alveolar crest at Level A. Also, the CBCT analysis algorithm may serve as a valuable tool for clinicians in determining optimal TAD placement in different dental regions. 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

Objective: This study compared the tooth movement patterns of a power arm and a lever jig during mandibular canine retraction into a premolar extraction space using skeletal anchorage. Methods: A finite element model was developed based on anatomical structures. A mini-implant was placed between the mandibular second premolar and first molar, and canine retraction was simulated using a power arm and a lever jig. The lever jig’s vertical arm lengths were 6 mm, 8 mm, and 10 mm, corresponding to force application distances of 4.5 mm, 6.4 mm, and 8.2 mm from the archwire, matching the power arm. Finite element analysis was performed using linear mechanical properties and an explicit method. Results: With the power arm, increasing vertical length led to greater extrusion, while the posterior force remained unchanged. The lever jig also showed increased extrusion with length but to a lesser extent. Posterior force increased proportionally with the lever jig length. Initial displacement analysis showed greater extrusion and distal tipping with the power arm, while the lever jig suppressed extrusion and facilitated controlled tipping. Stress analysis revealed a more uniform periodontal ligament stress distribution with the lever jig. Conclusion: The lever jig minimizes extrusion and enhances force concentration posteriorly, promoting efficient distal movement. Full article

Background: Hydrostatic pressure in the periodontal ligament (PDL) plays a critical role in orthodontic treatment, influencing tooth movement and remodeling of periodontal tissue. The relationship between alveolar cortical bone density and the risk of root resorption due to excessive stress in the PDL has not been clearly defined. Objective: This study aimed to analyze hydrostatic pressure in the periodontal ligament of the tooth roots during en-masse retraction of the maxillary incisors using temporary skeletal anchorage devices (TISADs) after the first premolar extractions, as well as during full arch retraction. Methods: A numerical model was used, varying the Young’s modulus of cortical bone from 12.5 GPa to 27.5 GPa in increments of 3.0 GPa. Extreme values for bone stiffness were derived from the literature. In all the cases analyzed, the hook height was fixed at 6 mm, and the cranial surface was constrained. Results: Doubling the stiffness of the cortical bone approximately reduced the hydrostatic pressure in the PDL by 1.5 times for both full-arch retraction and post-first premolar extraction retraction. A critical hydrostatic pressure of 4.7 kPa was exceeded in full-arch retraction for low Young’s modulus of 12.5 Gpa values at forces as low as 600 g. On the contrary, for cortical bone with a high Young’s modulus of 27.5 GPa, this critical pressure was reached only at forces around 960 g, approximately 1.6 times higher. Conclusions: The density of the alveolar cortical bone significantly influences the hydrostatic pressure in the PDL of most tooth roots during orthodontic treatment. This parameter can be a critical factor in the risk of root resorption when optimal forces are exceeded. Further research is necessary to better understand these dynamics. Individual protocols for orthodontic treatment and CBCT imaging are necessary to minimize complications in the form of root resorption. Full article

This study introduced a novel force-driven automated staging design method for clear aligners, aimed at enhancing treatment planning efficiency and outcomes. The method simplified the alignment process into a force-driven mechanics model that calculates forces and moments exerted on teeth while adhering to Newton’s third law, determining their displacement and rotation at each position. An optimal path was generated by iteratively moving teeth from their initial to target positions and subsequently divided into stages based on a predefined step size. The algorithm was implemented in C++ and incorporated into the WebGL-based SmarteeCheck3.0 software for visualization. In a maxillary extraction case, the automated staging method (0.25 mm step size) generated 51 stages in merely 5 s, while manual staging (>0.25 mm step size) necessitated 30 min to achieve 55 stages. In a molar distalization case, the automated method demonstrated similar efficiency advantages, generating 30 stages for the maxilla and 34 for the mandible, compared to 41 stages each in manual staging. The automated staging approach yielded shorter and more precise tooth movement paths that adhered to aligner biomechanics and physical principles, surpassing the limitations of manual staging. For cases requiring entire arch displacement, the method incorporated sequential movements with anchorage control to maintain force equilibrium. This innovative method substantially improved design efficiency and accuracy, ultimately elevating the efficacy of clear aligner therapy, although further biomechanical analyses and experimental validations are needed to refine the model parameters. Full article

A simplified mechanics model of aligner–tooth interaction was developed to establish a precise computational method for overcorrection design in clear aligner orthodontics. Validated through finite element analysis and experiments, the results demonstrated that designing the movement of only the target teeth on the aligner leads to uneven force distribution on adjacent teeth, while an overcorrection design can evenly distribute the reaction force generated by pushing the target teeth to the anchorage teeth, reducing the maximum force on the anchorage teeth, minimizing unplanned tooth movement, and improving the efficacy of the designed tooth movement for all teeth. Full article

Background/objectives: This retrospective longitudinal outcome study comparing orthodontic extraction modalities, including extraction of maxillary first or second molars, aimed to compare the three-dimensional tooth movement of maxillary canines (C), premolars (P1, P2), and molars (M1, M2) in Class II division 1 malocclusion treatment with fixed appliances. Methods: A sample of 98 patients (mean age 13.20 ± 1.46 years) was selected for the M1 group, and 64 patients (mean age 13.20 ± 1.36 years) were chosen for the M2 group. Tooth movement was analyzed three-dimensionally on pre-treatment (T0) and post-treatment (T1) digital dental casts. Regression analyses compared the tooth movements (in mm) between the M1 and M2 groups. Results: The mean treatment duration for the M1 group was 2.51 ± 0.55 year, while, for the M2 group, it was 1.53 ± 0.37 year. The data showed limited distal movements of the C, P1, and P2 of approximately 2 mm in the M1 group and 1 mm in the M2 group during orthodontic treatment, but the M1 group exhibited significantly more distal movements than the M2 group (mean difference 1.11 to 1.24 mm). Vertical movements of the C, P1, and P2 in both groups were also minor (0.16 to 1.26 mm). The differences between groups did not exceed 0.2 mm and were not significant. Both treatment modalities resulted in a significant degree of anchorage loss with a distinct mesialization (8.40 ± 1.66 mm) of M2 in the M1 group and limited distalization (0.83 ± 0.98 mm) of M1 in the M2 group. Conclusions: The findings highlight the importance of thorough case evaluation when choosing between extraction modalities in Class II treatment. If a large distal movement of canines and premolars is required, additional anchorage mechanics should be considered. Full article

Objectives: Mandibular molar distalization is a complex orthodontic movement due to anatomic and biomechanical limitations. The opportunity to use a custom-made appliance with skeletal anchorage should be an advantageous alternative to traditional solutions: multiple extractions, interproximal reductions, vestibular inclination of incisal group. Methods: A 14-year-old female patient with Class II malocclusion and ectopic upper and lower canines was treated in the lower arch with a custom-made appliance anchored on a mini-screw in the right buccal-shelf where the ectopy and crowding was severe. The miniscrew was connected to a rigid arm with a rail equipped with a coil that activated promoted the distalization of first and second molars bonded with metallic bands. Results: After 8 months of treatment with activations repeated every 4 weeks, an effective distalization has been reached. Conclusions: Mandibular molars’ distalization is a challenging orthodontic result to achieve. When the need to obtain space cannot be beneficially obtained with conventional approaches, and distalization of the lower molars could be desirable, a custom distalization device with skeletal anchorage and biomechanics based on a pressed coil sliding on a rigid arm is an efficient solution. Full article

Background: Achieving ideal anchorage is crucial in orthodontics for controlled tooth movement. Miniscrews (MSs) have improved skeletal anchorage, but freehand placement poses risks like root damage and limited precision. Guided techniques, including radiographic guides and computer-assisted methods (static [sCAS] and dynamic [dCAS]), were developed to enhance accuracy and safety. Objective: This systematic review and meta-analysis aimed to evaluate the safety and accuracy of MS placement using different guidance approaches. Materials: A systematic search up to March 2024 identified studies on guided MS insertion, assessing safety (root contact/damage) and accuracy (angular, coronal, and apical deviations) of guided vs. freehand placement. Two reviewers assessed the risk of bias and study quality using RoB 2 for RCTs, NOS for cohort studies, and an adapted tool for pre-clinical studies. Random-effects meta-analysis was performed for studies with common parameters, and safety outcomes were pooled using logit-transformed proportions. Heterogeneity was evaluated with I² and χ² tests. Results: Eleven studies (652 MSs) were included, though no dCAS studies were analyzed. The only RCT had “some concerns” regarding risk of bias, cohort studies ranged from medium to low quality, and most pre-clinical studies had high bias risk. sCAS significantly reduced root damage compared to freehand methods (OR = 0.11; 95% CI: 0.04–0.36; p < 0.001; I² = 1%) and reduced angular and linear deviations. Due to heterogeneity, no quantitative synthesis of accuracy outcomes was performed. Conclusions: sCAS improves the safety and accuracy of MS insertion compared to freehand and radiographic guide methods. These results highlight the clinical benefits of sCAS in orthodontics. Future studies should refine protocols and explore dCAS for further accuracy improvements. Full article

Backgroud: Orthodontic treatment plans face challenges when deciding on tooth extraction, particularly when the retraction of incisors leads to a flattening of the lip curvature. Despite the significance of this issue, quantitative measurements of curvature have not been previously undertaken. This study presents novel soft tissue measurements, namely SAL (A’toSn-Ls) depth, SAL angle, PBL (B’toLi-Pg) depth, and angle, as tools for assessing lip curvature. The aim of this study was to assess whether new parameters demonstrated more pronounced flattening of the upper and lower lips in the extraction group compared to the non-extraction group. Methods: A total of sixty-two patients diagnosed with skeletal Class I malocclusion and treated with extraction or non-extraction orthodontic treatment were included and compared. Cephalometric measurements were analyzed and compared between the initial and final stages of treatment. Results: The difference in SAL (1.99°) and PBL (4.41°) angles and other soft tissue measurements between the groups was not statistically significant. Multiple regression analysis yielded the equation: ΔSAL = 0.66ΔU1 tip – 0.98ΔL1 tip – 1.58. Conclusions: Flattening of the upper lip was not significantly displayed on moderate anchorage. Consequently, orthodontic treatment accompanying the retraction of the upper incisors does not always result in obtuse lip profiles. Full article

Background: Dental implants are commonly employed to address edentulism, while orthodontic treatments often incorporate mini-screws to enhance tooth movement and provide stable anchorage. Both procedures are integral to modern dental practice and frequently interact in comprehensive care scenarios. While oral health professionals routinely assess patients’ medical histories before procedures, undiagnosed coagulopathies, such as Von Willebrand Disease (VWD), can present significant challenges when invasive procedures are carried out, such as the insertion of implants or mini-implants. Case description: This case report discusses the surgical placement of dental implants and orthodontic mini-screws in a patient with previously undiagnosed VWD, underscoring the potential complications and the importance of recognizing bleeding disorders in clinical practice, and provides some advice on the management of patients with previously undiagnosed VWD after/during surgical procedures. Conclusions: To prevent the risk of excessive bleeding, before surgery, all patients should be screened through precise questions on bleeding history. Full article

This paper presents a new type of large-diameter multi-disc soil anchor and its cavity-forming tool. The large-diameter multi-disc soil anchor is obtained by adopting a toothed chain, centrifuging holes to form cavities, forming multiple cavities, placing a steel strand with centering support, injecting cement mortar, and curing. In order to study the uplift bearing characteristics and creep property of the large-diameter multi-plate soil anchor, the equal-diameter soil anchor was taken as the control group. The ultimate pull-out bearing capacity, vertical displacement, axial force, anchor plate bearing load, and side friction resistance were simulated and analyzed by FLAC3D 5.0 64-bit software, and the creep property test of the anchor bolt was carried out. The results show that under the same conditions, the ultimate pulling capacity of the large-diameter multi-disc soil anchor is 125% higher than that of the same-diameter soil anchor. The vertical displacement of the large-diameter multi-disc soil anchor decreases by 51.74% compared with that of the equal-diameter soil anchor when the ultimate uplift capacity is reached. The side friction resistance of the large-diameter multi-disc soil anchor is small and its growth rate is slow. When the ultimate pulling capacity is reached, the load sharing of the anchor disc accounts for 76.54% of the total load applied. The creep rate of the large-diameter multi-plate soil anchor bolt is 0.91 mm, and the creep rate of the equal-diameter soil anchor bolt is 1.69 mm. By fitting the data, it is found that the large-diameter multi-disc soil anchor provides a method to increase the anchorage force of the soil anchor, and the research on its bearing characteristics and creep property provides a theoretical basis for the application of the soil anchor. Full article

Aims: It was the scope of this study to explore the biomechanical implications of retraction force application point modifications in lingual orthodontics, aiming to mitigate the bowing effect and enhance anchorage stability in the anterior teeth. Methods: Using the FE method on an idealized maxillary model, en masse retraction was simulated using a modified lingual fixed appliance including edgewise lingual brackets, a 0.017″ × 0.025″ mushroom-shaped archwire, and power arms between lateral incisors and canines, with a transpalatal arch (TPA) connecting the first molars. Applying bilateral retraction forces of 1.5 N at twelve positions, initial tooth displacements during space closure were evaluated. Results: Shifting power arms gingivally did not effectively counteract palatal tipping of incisors but reduced posterior and palatal tipping of canines with a power arm length of 11.3 mm preventing posterior tipping. Apically displacing the TPA retraction force increased mesiobuccal rotation while preventing mesial molar tipping for retraction forces applied 12.6 mm from the archwire. Conclusions: Apically shifting retraction forces can mitigate vertical bowing effects in lingual orthodontics, yet it also highlights the challenges in maintaining torque in the anterior teeth. Further research and clinical validation are essential in order to confirm these results, emphasizing the complexity and need for advanced biomechanical strategies in personalized lingual orthodontic treatments. Full article