Evaluation of the success of predicted dental changes with clear-aligner treatment: A pilot study.

Objective: This pilot study concerned evaluation of the success of predicted dental changes in patients presenting with Class I malocclusions who were submitted to treatment aligners, using the superimposition. Methods: The digital models were superimposed and analyzed using 3DSlicer 5.0 software. Treatment and predicted changes regarding horizontal and vertical linear displacements, mesiodistal rotations, and incisor buccolingual tipping were quantified. The success rates were calculated by dividing the mean treatment change amount by the predicted change amount. Results: Lower-incisor intrusion was the most accurate of the predicted vertical displacements (86.96 %), and buccal expansion of upper canines (99.32 %) and mesial translation of the lower incisors (98.57 %) were the most accurate horizontal linear displacements. The predicted rotation was achieved with the highest accuracy for lower incisors (75.69 %). Incisor buccolingual tipping success rates ranged between 45.78 % and 69.31 %. Low accuracy of predicted changes was found for upper-molar extrusion (10.23 %) and constriction (8.91 %). However, minimal corrections in these directions were planned. Conclusions: Dental changes for all regions of maxillary and mandibular arches could be evaluated. High success rates were observed for most of the movements planned for ClearCorrect aligner therapy.

Effect of orthodontic space closure on dental pulp sensitivity. Prospective clinical trial.

BACKGROUND: Orthodontic tooth movement (OTM) is a biological process that can influence the function of the pulp, including its innervation. The excitability of the nerve fibres of the pulp may be altered by forces exerted on the nerve fibres or by reduced blood flow to the pulp. The aim of this clinical study was to evaluate the sensitivity of the dental pulp during levelling and during the phase of space closure, to assess the role of certain controlled risk factors. METHODS: Twenty-two adolescent participants requiring orthodontic space closure in transcanine sector were enrolled in a prospective clinical study. Patients were observed before OTM, after levelling and 1 month during active space closure. The sensitivity threshold of the pulp was measured using the electric pulp test (EPT). Dental models were obtained using an intraoral scanner, allowing measurement of interdental distances and calculation of OTM speed. The teeth were categorized according to position and tooth type. RESULTS: The EPT values increased significantly during orthodontic treatment (one-way RM-ANOVA, P = .014). There was a significant difference in EPT values between the tooth categories. Teeth with a single root adjacent to the residual space had the highest EPT thresholds (two-way RM-ANOVA, P < .001; Holm-Sidak, P < .05). CONCLUSIONS: OTM reduced pulpal sensitivity. Pulpal sensitivity during active space closure was similar to sensitivity during the levelling phase. The pulpal sensitivity of molars was less affected by OTM than that of single-rooted teeth, while teeth closer to the gap had a significantly higher pulpal sensitivity threshold during active OTM.

The biological effects of Piezocision™ on bone for accelerated tooth movement: A systematic review of animal studies.

OBJECTIVES: This systematic review aimed to assess the biological response at tissue, cellular, and molecular levels following Piezocision™ surgery, and its efficacy in accelerating orthodontic tooth movement. MATERIAL AND METHODS: A systematic review of the literature was conducted across 4 databases following the PRISMA guidelines up to May 2022. Prospective controlled animal studies involving healthy animals under active orthodontic treatment assisted by corticotomy performed with a piezotome (Piezocision™) published in the English language without time restrictions were included. The article selection, data extraction and risk of bias assessment (SYRCLE tool) were performed by two independent blinded review authors. RESULTS: Out of 738 articles screened, 10 studies were included with various level of bias. Biological responses were categorized into tissue, cellular, and molecular levels. Tissue-level changes included a global decrease in bone mineral content post-Piezocision™. At the cellular level, increased bone turnover activity was noted. Molecularly, elevated RANKL and OPG expression, along with increased TRAP+ and cytokines, were observed after Piezocision™. Studies confirmed Piezocision's efficacy, reporting 1.35 to 3.26 times faster tooth movements, peaking between the 3rd and 50th day post-surgery. Biological responses were transient, reversible, and proportional to surgical insult, with reactivation possible through a second Piezocision™. CONCLUSIONS: After Piezocision™ surgery, a transient and reversible biological response was described at the tissue, cellular and molecular levels, which induced faster orthodontic tooth movements. This biological response could be re-activated by an additional Piezocision™ and is proportional to the surgical injury. SYSTEMATIC REVIEW REGISTRATION: Prospero CRD42022303237.

Comparison of the efficiency of initial dental alignment with Invisalign® aligners changed every 7 or 14 days in mature adults: Randomized clinical trial.

OBJECTIVE: To compare the anterior crowding correction after sequential use of the first 5 aligners between two aligner exchange protocols (7 and 14 days) in mature adult patients. MATERIALS AND METHODS: Thirty-six patients over 35 years who received orthodontic treatment with Invisalign® were randomly allocated to two different aligner replacement sequence protocols: Group 1: exchange every 7 days (n = 18); and Group 2: exchange every 14 days (n = 18). All patients were scanned with iTero Element 5D® (Align Technology) in two treatment times: at pre-treatment (T1) and after using the first five aligners (T2). Little's Irregularity Index (LII) and arch widths were evaluated with OrthoCAD software. Intra and intergroup comparisons were performed with the dependent and independent t-tests. The results were considered significant for P < .05. RESULTS: Thirty-five patients completed the study. Both groups' maxillary and mandibular Irregularity Indexesi were significantly lower at T2. There was no significant difference in inter-canine, inter-premolar, and intermolar distances. G2 (14 days) presented a greater decrease in mandibular irregularity than G1 (7 days). CONCLUSION: Both exchange protocols (7 and 14 days) effectively correct anterior crowding in the initial phase of orthodontic treatment with aligners in mature adult patients. However, the 14-day exchange protocol provided a greater correction in mandibular anterior crowding in the evaluated period than the 7-day exchange protocol.

The effect of micro-osteoperforations on the rate of maxillary incisors' retraction in orthodontic space closure: a randomized controlled clinical trial.

BACKGROUND: This single-centered randomized controlled clinical trial aimed to evaluate the effectiveness of micro-osteoperforations (MOPs) in accelerating the orthodontic retraction of maxillary incisors. METHODS: Forty-two patients aged 16-40 were recruited and randomly assigned into two groups, one which underwent MOPs (MOPG) in the buccal and palatal region of all maxillary incisors immediately before the start of retraction and one which did not (CG). Eligibility criteria included the orthodontic need for maxillary first premolars extraction and space closure in two phases. The primary outcome of the study consisted of measuring the rate of space closure and, consequently, the rate of incisors' retraction using digital model superimposition 14 days later and monthly thereafter for the next 4 months. The secondary outcomes included measuring anchorage loss, central incisors' inclination, and root length shortening, analyzed using cone beam computed tomography scans acquired before retraction and 4 months after retraction. Randomization was performed using QuickCalcs software. While clinical blinding was not possible, the image's examinator was blinded. RESULTS: Twenty-one patients were randomly assigned to each group. However, due to various reasons, a total of 37 patients (17 male and 20 female) were analyzed (mean age: 24.3 ± 8.1 years in the MOPG; 22.2 ± 4.2 years in the CG) during the trial. No statistically significant difference was found between the MOPG and the CG regarding the incisors' retraction measured at different time points at the incisal border (14 days, 0.4 mm vs. 0.5 mm; 1 month, 0.79 mm vs. 0.77 mm; 2 months, 1.47 mm vs. 1.41 mm; 3 months, 2.09 mm vs. 1.88 mm; 4 months, 2.62 mm vs. 2.29 mm) and at the cervical level (14 days, 0.28 mm vs. 0.30 mm; 1 month, 0.41 mm vs. 0.32 mm; 2 months, 0.89 mm vs. 0.61 mm; 3 months, 1.36 mm vs. 1.10 mm; 4 months, 1.73 mm vs. 1.39 mm). Similarly, no statistically significant differences were detected in the space closure, anchorage loss, central incisors' inclination, and radicular length between groups. No adverse effect was observed during the trial. CONCLUSIONS: MOPs did not accelerate the retraction of the maxillary incisors, nor were they associated with greater incisor inclination or root resorption. Trial registration ClinicalTrials.gov NCT03089996. Registered 24 March 2017- https://clinicaltrials.gov/ct2/show/NCT03089996 .

Eficiência da prescrição de bráquetes ortodônticos no tratamento com diferentes sistemas de bráquetes - uma proposta clínica / Orthodontic bracket prescription efficiency in treatment with different bracket systems - a clinical proposal

Com a diversificação das prescrições existentes, a correta escolha de acordo com a necessidade individual de cada má oclusão pode ser importante para estabelecer maior controle biomecânico durante o tratamento ortodôntico. Este estudo teve como objetivo avaliar o tratamento ortodôntico com a versatilidade na associação de diferentes prescrições em um relato de caso clínico e determinar se existe alguma relação com a dimensão vertical, transversal e o perímetro de arco que podem contribuir com a estabilidade e longevidade do tratamento ortodôntico. A prescrição, quando corretamente indicada, tem impacto no controle do movimento dentário para estabelecer oclusão, estética e estabilidade adequadas. Concluiu-se que o surgimento de novas prescrições tende a favorecer ao máximo a abrangência de mais pacientes no tratamento ortodôntico (AU)

With the diversification of existing bracket prescriptions, the correct choice according to the individual needs of each malocclusion is essential to establish greater biomechanical control during orthodontic treatment. This study aimed to evaluate orthodontic treatment with the versatility in association of different prescriptions in a clinical case report and to determine whether there is any relationship with the vertical dimension, transverse dimension, and arch perimeter that can contribute to the stability and longevity of the orthodontic treatment. The prescription, when correctly indicated, has an impact on the control of tooth movement to establish proper occlusion, esthetics, and stability. It was concluded that the emergence of new prescriptions favors the maximum coverage of more patients in orthodontic treatment. (AU)

Research progress on applications and mechanisms of osteogenesis effect of magnetic fields in oral field / 口腔疾病防治

@#Magnetic fields are safe and used in noninvasive physical therapies. Numerous studies have confirmed that magnetic fields have good osteogenic effects and certain value for clinical application in accelerating orthodontic tooth movement, promoting bone-implant integration, promoting fracture healing and improving the effects of distraction osteogenesis. Magnetic fields are expected to become applied as effective auxiliary methods for treating oral diseases. To support the clinical application of magnetic fields, this article reviews the applications of magnetic fields in the oral cavity, the biological effects on bone cells and the molecular mechanisms through which magnetic fields regulate bone metabolism. The biological effects of magnetic fields on bone cells include promoting osteogenesis by osteoblasts and mesenchymal stem cells and inhibiting bone resorption by osteoclasts. At the molecular level, bone cells sense and respond to magnetic stimulation, and through various mechanisms, such as displacement currents, Lorentz forces, and free radical pair effects, stimuli are transformed into biologically recognizable electrical signals that activate complex downstream signaling pathways, such as the P2 purinergic receptor signaling pathway, adenosine receptor signaling pathway, transforming growth factor-β receptor signaling pathway, mammalian target of rapamycin (mTOR) pathway, and Notch pathway. In addition, magnetic parameters, which are the factors affecting the osteogenic effects of magnetic fields, are discussed. However, the mechanisms of the osteogenic effects of magnetic fields are unclear, and further studies of these mechanisms could provide effective strategies for bone regeneration and periodontal tissue regeneration. In addition, considering the target of magnetic field therapies, combination with other drugs could lead to new strategies for the treatment of oral diseases.

Comparative Efficacy of Traditional Corticotomy and Flapless Piezotomy in Facilitating Orthodontic Tooth Movement: A Systematic Review and Meta-Analysis.

Background and Objectives: This study aimed to perform a meta-analysis comparing the effects of corticotomy and flapless piezocision on accelerated tooth movement. Materials and Methods: A comprehensive search using a combination of controlled vocabulary (MeSH) and free-text terms was undertaken by two reviewers to identify published systematic reviews. Three major electronic databases (Medline via PubMed, Cochrane Database, and Embase) were searched up to 2 June 2023. Results: The results of the meta-analysis showed that the pooled standardized mean difference values of accumulative movement distances for flapless piezocision were 1.43 (95% CI, 0.38 to 2.48; p < 0.01), 1.09 (95% CI, -0.08 to 2.26; p = 0.07), and 0.73 (95% CI, -0.58 to 4.02; p = 0.14). The results of the meta-analysis demonstrated that the pooled SMD values of accumulative movement distances for the corticotomy were 2.76 (95% CI, 0.18 to 5.34; p = 0.04), 1.43 (95% CI, -1.10 to 3.96; p = 0.27), and 4.78 (95% CI, -4.54 to 14.10; p = 0.32). Although the test for overall effectiveness was significant for piezocision and corticotomy, there were no significant differences between piezocision and corticotomy. Conclusions: The study determined that both conventional corticotomy and flapless piezosurgery are effective as adjuncts to orthodontic treatment. Moreover, no significant difference was observed in the short-term effectiveness of canine retraction acceleration between conventional corticotomy and flapless piezocision. While piezocision may be a favorable option for orthodontic treatment, corticotomy can be considered in cases requiring additional procedures such as bone grafting.

Orthodontic treatment in traumatized permanent teeth: a systematic review / Tratamento ortodôntico em dentes permanentes traumatizados: uma revisão sistemática

Objective: to analyze, through literature review, the available literature on orthodontic treatment in traumatized permanent teeth. Methods: A literature search was performed in electronic databases (PubMed and SciELO) using the descriptors [tooth injuries] OR [injuries, teeth] OR [injury, teeth] OR [teeth injury] OR [injuries, tooth] OR [injury, tooth] OR [tooth injury] OR [teeth injuries] AND [orthodontics]. Observational studies and clinical trials were included, narrative reviews, laboratory and in vitro studies, case reports and series as well as articles that presented abstracts written in languages other than Portuguese, English and Spanish were excluded from the study. Two reviewers considered the eligibility, the risk of bias of the analyzed data and the qualitative synthesis of the studies included. A total of 1,322 references were found and 4 articles met all inclusion criteria and were included in the qualitative analysis. Some consequences like pulp necrosis and root resorption have been highlighted and trauma severity should be considered when orthodontically intervening in previously traumatized teeth. Final considerations: The traumatized teeth can be orthodontically treated as long as the time of tissue reorganization is respected, and the pull and periodontal conditions are followed up.(AU)

Objetivos: analisar, por meio de revisão de literatura, a respeito do tratamento ortodôntico em dentes permanentes traumatizados. Metodologia: Uma pesquisa bibliográfica foi realizada em bancos de dados eletrônicos (PubMed e SciELO) usando os descritores [tooth injuries] ou [injuries, teeth] ou [injury, teeth] ou [teeth injury] ou [injuries, tooth] ou [injury, tooth] ou [tooth injury] ou [teeth injuries] e [orthodontics]. Foram incluídos estudos observacionais e ensaios clínicos, revisões narrativas, estudos laboratoriais e in vitro, relatos de casos e séries, bem como artigos que apresentassem resumos redigidos em idiomas diferentes do português, inglês e espanhol foram excluídos do estudo. Dois revisores consideraram a elegibilidade, o risco de viés dos dados analisados e a síntese qualitativa dos estudos incluídos. Foram encontradas 1.322 referências e 4 artigos atenderam a todos os critérios de inclusão e foram incluídos na análise qualitativa. Algumas consequências como necrose pulpar e reabsorção radicular têm sido destacadas e a gravidade do trauma deve ser considerada na intervenção ortodôntica em dentes previamente traumatizados. Considerações finais: Os estudos incluídos nesta revisão sugerem que dentes traumatizados podem ser tratados ortodônticamente desde que respeitado o tempo de reorganização tecidual e acompanhadas as condições pulpares e periodontais.(AU)

Calcitonin as a pharmacological anchorage in orthodontics.

Objective: This study aimed to evaluate the effects of salmon calcitonin administration as a pharmacological anchoring agent in orthodontics and to determine the influence of locally applied calcitonin on serum calcium levels. The secondary aim was to observe the response of dental and periodontal tissues using light microscopy. Methods: Fourteen healthy male adult Wistar rats with an average weight of 250 g had their teeth moved, seven of which received a local injection of salmon calcitonin in the furcation region of the left upper first molar. Concurrently, the remaining seven were used as controls. In the control group, saline solution was injected in the bifurcation region of tooth 26 to subject these animals to the same stress level as those of the experimental group. After 14 days, a 6 mm diameter orthodontic elastic band was inserted between teeth 26 and 27 in all animals to induce the movement of these teeth. The rats were anaesthetised and exsanguinated on day 21. In both groups, tooth movement and serum calcium levels were measured. The jaws were dissected with straight scissors, and tissue blocks containing gingiva, bone and teeth were identified, fixed and demineralised. Then, the pieces were cut into semi-serial slices, stained with hematoxylin, eosin, and Mallory's trichrome, and analysed under an Axiophot light microscope. Results: There was significantly less tooth movement in the experimental group (X̄; 0,150 mm ± 0,037) than in the control group (0,236 mm ± 0,044; P = 0,003), while there was no significant difference in serum calcium levels between the two groups (controlX̄; 9,53 mg/dl ± 1,53; experimental 10,81 mg/dl ± 1,47; P = 0,15). Conclusion: While calcitonin did not completely inhibit osteoclast activity, it promoted orthodontic anchorage, apparently, by local action.

Predictability and Effectiveness of Nuvola® Aligners in Dentoalveolar Transverse Changes: A Retrospective Study.

Nowadays, many people use clear aligners to address their dental issues. The efficacy of transparent dental aligners must be investigated even though they are more aesthetically pleasing, easy to use, and tidy than permanent tools. Thirty-five patients in this study's sample group who used Nuvola® clear aligners for their orthodontic therapy were prospectively observed. Initial, simulated, and final digital scans were analysed with a digital calliper. The actual results were compared with the prescribed ending position to evaluate the efficacy of transversal dentoalveolar expansion. Aligner treatments in Groups A (12) and B (24), particularly in the dental tip measures, demonstrated high adherence to the prescription. On the other hand, the gingival measures exhibited a greater level of bias, and the differences were statistically significant. However, there was no difference in the outcomes between the two groups (12 vs. 24). Within specific parameters, the evaluated aligners were shown to be helpful in predicting movements in the transverse plane, particularly when considering movements linked to the vestibular-palatal inclination of the dental elements. This article compares the expansion effectiveness of Nuvola® aligners compared with other work in the literature using competitor companies.

Randomized clinical trial on the effect of intermittent vibrational force application during orthodontic treatment with aligners on RANKL and OPG concentrations in crevicular fluid.

Application of intermittent forces by vibration is proposed as an easy-to-use accelerator of dental movement. The purpose of this study was to determine the effect of intermittent vibrational force application during orthodontic aligner treatment on receptor activator of nuclear factor-kappa B ligand (RANKL) and osteoprotegerin (OPG) concentrations in crevicular fluid as markers of bone remodeling. This three-arm parallel randomized clinical trial included 45 candidates for malocclusion treatment with aligners, randomly assigned to: Group A (vibrational forces from onset of treatment); Group B (vibrational forces at 6 weeks after treatment onset); or Group C (no vibration). The frequency of aligner adjustment also differed among groups. At different time points, a paper tip was used to draw crevicular fluid samples from a moving lower incisor for RANKL and OPG analysis using ELISA kits. Mixed-model ANOVA found no significant differences in RANKL (A: p = 0.31, B: p = 0.8, C: p = 0.49) or OPG (A: p = 0.24, B: p = 0.58, C: p = 0.59) over time in any group or as a function of the application/non-application of vibration or the frequency of aligner adjustments. Application of this accelerator device did not significantly affect bone remodeling in patients undergoing orthodontic treatment with aligners. However, a nonsignificant improvement in biomarker concentrations was observed when aligners were changed every 7 days and vibration was also applied. Further research is warranted to establish protocols for the application of vibration and the timing of aligner adjustments.

The effect of orthodontic tooth movement on the sensitivity of dental pulp: A systematic review and meta-analysis.

Objectives: Orthodontic tooth movement (OTM) is a process that's initiated by orthodontic forces. As a consequence, the forces could restrict pulpal blood supply, possibly affecting dental pulp. The study aimed to review the available evidence on the short and long-term effects of orthodontic tooth movement on dental pulp sensitivity and to identify clinically relevant risk factors. Sources: PubMed, Embase, Scopus, and Web of Science were searched for papers from 1990 to the end of December 2021. Study selection: The studies that evaluated dental pulp sensitivity of teeth undergoing OTM were included in the systematic review. Randomized, nonrandomized and case-controlled studies were included in the analysis. Risk of bias in each study was assessed using the ROBINS-I tool. Data: The systematic search yielded an initial sample of 1110 studies, 17 were included in qualitative analysis. Most studies were classified as moderate risk of bias, however only limited long-term evidence with a higher risk of bias exists. Electric pulp test (EPT) sensitivity threshold during active OTM was increased by 4.25 SD (P < 0.001) and the relative risk (RR) of pulpal non-sensitivity was 13.27 (P < 0.001) higher compared to pre-orthodontic baseline status. Significant differences were between subgroups associated with the type of OTM. A positive relationship between pulpal non-sensitivity and mean patient age was discovered (P = 0.041). After OTM the risk of pulpal non-sensitivity remained 5.76 times higher (P < 0.001) in the long term. Conclusions: Evidence showed that OTM could affect dental pulp sensitivity. The type of OTM and patients' age were identified as clinically relevant risk factors. Clinical significance: Orthodontic tooth movement negatively impacts the sensitivity of dental pulp during active treatment and to a lesser degree in the long term. Pulpal sensitivity tests during active OTM should therefore be interpreted with caution. Data indicates younger patients have a lower risk of negative pulpal sensitivity during orthodontic treatment.

Analgesia por láser de baja potencia en pacientes con tratamiento ortodóncico / Low power laser analgesia in patients with orthodontic treatment i: en

Introducción: El dolor es el síntoma más común luego de la primera activación de la aparatología ortodóncica. El tratamiento analgésico más utilizado es el paracetamol; sin embargo, su uso inhibe la actividad de la ciclooxigenasa y la síntesis de prostaglandinas, lo que puede afectar el mecanismo del movimiento dental y el remodelado óseo. Objetivo: Evaluar la efectividad del láser de baja potencia para el alivio del dolor en pacientes con tratamiento ortodóntico. Métodos: Se realizó un estudio cuasiexperimental de intervención terapéutica, desde enero hasta diciembre de 2020, en 40 pacientes atendidos en la consulta de ortodoncia del Hospital General Docente Dr. Juan Bruno Zayas Alfonso de Santiago de Cuba, en quienes se aplicaría fuerza ortodóncica por primera vez. Estos fueron distribuidos de forma aleatoria en 2 grupos de 20 integrantes cada uno: el de estudio, tratado con láser de baja potencia, y el de control, que recibió medicación convencional (paracetamol). Para la validación estadística de la información se emplearon el porcentaje y la prueba de la t de Student para muestras independientes, con 95 % de confiabilidad. Resultados: Luego de tres sesiones terapéuticas, 90,0 % del grupo de estudio refirió no presentar dolor o sentirlo de forma leve, mientras que del grupo de control solo 10,0 % de los pacientes fue ubicado en cualquiera de las dos categorías anteriores. Existió diferencia significativa entre ambos grupos (p=0,00). Conclusiones: Se demostró que el láser, como terapia alternativa, fue más efectivo que el paracetamol.

Introduction: Pain is the most common symptom after the first activation of orthodontic appliance. The most widely used analgesic treatment is paracetamol; however, its use inhibits cyclooxygenase activity and prostaglandin synthesis, which can affect the mechanism of tooth movement and bone remodeling. Objective: To evaluate the effectiveness of low power laser for pain relief in patients with orthodontic treatment. Methods: A quasi-experimental study of therapeutic intervention was carried out, from January to December 2020, in 40 patients treated at the orthodontic clinic of Dr. Juan Bruno Zayas Alfonso Teaching General Hospital in Santiago de Cuba, in whom orthodontic force was applied for the first time. These were randomly distributed into 2 groups of 20 members each: the study group, treated with low-power laser, and the control group, that received conventional medication (paracetamol). For statistical validation of data, the percentage and the Student's t test for independent samples were used, with 95 % confidence interval. Results: After three therapeutic sessions, 90.0% of the study group reported not presenting pain or feeling it slightly, while only 10.0% of patients in control group were put in any of the two previous categories. There was a significant difference between both groups (p=0.00). Conclusions: Laser, as an alternative therapy, was shown to be more effective than paracetamol.

Evaluation of stress distribution values at the temporomandibular joint and distalization of teeth during en-masse retraction of the mandibular dentition using buccal shelf bone screws: A FEM study.

INTRODUCTION: Present Finite-element-method (FEM) study evaluates the stress distribution values at the Temporomandibular-Joint (TMJ) during en-masse retraction of the mandibular dentition using buccal shelf bone screws with varying magnitudes of forces. MATERIAL AND METHODS: Nine replicas of a pre-existing three-dimensional finite element model of the craniofacial skeleton and articular disc from Cone-Beam-Computed-Tomography (CBCT) data and Magnetic-Resonance-Imaging (MRI) data of a patient were used. Buccal shelf (BS) bone screws were inserted buccal to the mandibular second molar region. Forces of magnitudes 250 gm, 350 gm and 450 gm were applied through NiTi coil springs along with stainless-steel archwires of sizes 0.016 × 0.022-inch, 0.017 × 0.025-inch and 0.019 × 0.025-inch. RESULTS: On the articular disc, the maximum stress was observed at the inferior region and the inferior part of the anterior and posterior zone at all force levels. The stress on the articular disc and displacement of teeth increased with increase in force levels in all the 3 archwires. The maximum stress at the articular disc and displacement of teeth was observed for 450 gm force and the least for 250 gm force. No significant difference in the amount of displacement of teeth or the stresses produced at the articular disc was seen with increasing the size of the archwire. CONCLUSION: With the present FEM study, we can deduce that it is better to use forces of lower levels on patients with temporomandibular-disorders (TMD) so as to reduce the stresses produced at the TMJ to avoid worsening of the TMD condition.

Friction and archwire engagement in contemporary self-ligating appliance systems : An in vitro comparison.

PURPOSE: The aim of this study was to compare classical friction (FR) in passive self-ligating brackets (P-SLBs), active self-ligating brackets (A-SLBs) and a traditional twin bracket, in vitro, and to identify the point of initiation of bracket-archwire engagement. METHODS: Nine bracket systems of 0.022 in slot size were FR tested: 5 P­SLB systems; 4 A­SLB systems; and a control group of twin brackets with elastomeric ligatures. Single upper right central incisor brackets were mounted on a custom metal fixture for testing. Straight sections of various round and rectangular nickel-titanium (NiTi) archwires (0.016, 0.018, 0.018â€¯× 0.018, 0.020â€¯× 0.020, 0.016â€¯× 0.022, 0.017â€¯× 0.025, 0.019â€¯× 0.025, and 0.021â€¯× 0.025 in) were ligated to the bracket and peak static FR (cN) was measured with an Instron Universal Testing Machine. Ten unique tests each utilizing a new bracket and new archwire were conducted for each group in the dry state. RESULTS: FR was significantly different between control, P­SLB and A­SLB systems (P < 0.001). P­SLB groups displayed no significant differences in FR between each other, regardless of archwire size. A­SLB groups did exhibit significant differences in FR between each other depending on both the bracket system and archwire size. Each A­SLB system tested possessed a distinctly different pattern of initiation of bracket-archwire engagement. CONCLUSIONS: FR between the archwire and bracket slot differs between P­SLB and A­SLB systems, with a distinct pattern of FR and bracket-archwire engagement for each A­SLB system. Understanding the different bracket-wire interactions of SLB systems should help orthodontic clinicians to plan effective and efficient biomechanics with the bracket system of their choice.

Rate of upper incisor retraction in Class II division 1 patients managed with palatal versus buccal miniscrew supported segmental orthodontics: Randomized parallel clinical trial.

OBJECTIVE: This study was conducted to compare maxillary incisor retraction rates using buccal orthodontics with segmented arch approach supported by a buccal or palatal mini-screw in non-growing Class II Division 1 patients during a 3-month period. PATIENTS AND METHODS: All patients between September 2018 and December 2021 with following criteria were included: non-growing class II division 1 protrusion, indication for premolar extraction, no or little crowding, normal overbite, no previous orthodontic treatment, no systematic disease, good oral hygiene, no periodontal problems or oral habits. Mini-implant was inserted buccally or palatally between upper second premolar and first molar bilaterally. Incisor retraction was manipulated by a 200-gram force through a nickel-titanium closed-coil spring extended from the mini-implant to the segmental design. Study casts were made before retraction and after every 4 weeks (T0: baseline, T1: 4 weeks, T2, 8 weeks, T3: 12 weeks). A repeated measures ANOVA was performed for total comparison of data (mm of retraction) on 3D casts. A pairwise t test with Bonferroni correction was used for comparison between two experimental periods for the same group. An independent samples t-test was also used for comparison between two groups for the same experimental period. RESULTS: Of 30 patients meeting the eligibility criteria, only 28 were included with mean age 16±2.5 years. Repeated measures ANOVA revealed significant differences in incisor retraction between the time intervals for both buccal and palatal groups (P=0.001). In addition, the paired-sample t test indicated a significant difference between each time interval for both the buccal and palatal groups (P=0.001), except between T3 and T2 for the palatal group (P=0.09). The independent sample t-test revealed significant differences between the buccal and palatal groups at T1 (Mean: 0.55 [0.355-0.748],=0.001) and T2 (Mean: 1.4 [0.91-1.88], P=0.001); whereas no significant difference was found at T3 (Mean: 1.15 [0.67-1.63], P=0.945). CONCLUSIONS: Anterior retraction using a segmental palatal model with mini-screws was effective regardless of the buccal or palatal situation of the minivis. Retraction of incisors with palatal miniscrews was significantly faster in the first two months.

Do platelet concentrates accelerate orthodontic tooth movement?: a systematic review.

PURPOSE: Surgical techniques in orthodontics have received widespread attention in recent years. Meanwhile, biomaterials with high molecular content have been introduced, such as platelet concentrates (PCs), which may accelerate orthodontic tooth movement (OTM) and reduce periodontal damage. The present systematic review aimed to answer the following PICO question: "In patients in whom orthodontic surgical techniques are performed (P), what is the effectiveness of using PCs over the surgical site (I) when compared to not placing PCs (C) to achieve faster tooth movement (O)?" METHODS: A search was performed in 6 databases. The criteria employed were those described in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses declaration. The present review included studies with a control group that provided information about the influence of PCs on the rate of OTM. RESULTS: The electronic search identified 10 studies that met the established criteria. CONCLUSIONS: The included studies were very diverse, making it difficult to draw convincing conclusions. However, a tendency was observed for OTM to be accelerated when PCs were used as an adjuvant for canine distalization after premolar extraction when distalization was started in the same session. Likewise, studies seem to indicate an association between PC injection and the amount of canine retraction. However, it is not possible to affirm that the use of PCs in corticotomy shortens the overall treatment time, as this question has not been studied adequately. TRIAL REGISTRATION: PROSPERO Identifier: CRD42021278542.

É possível realizar tracionamento ortodôntico cirúrgico em incisivo com dilaceração radicular? / Is it possible to perform surgical orthodontic traction on incisor with root dilaceration?

Resumo Introdução: O traumatismo dental na dentição decídua pode influenciar o desenvolvimento dos sucessores permanentes e causar um deslocamento da coroa em relação à raiz dental, gerando uma curvatura definida como dilaceração, que em grande parte dos casos impede a irrupção normal do dente permanente. Diversas são as possibilidades de tratamento, desde exodontia ao tratamento ortocirúrgico. Objetivo: O presente trabalho tem o objetivo de relatar um caso clínico de incisivo central superior esquerdo (21) com dilaceração radicular cujo tratamento envolveu procedimento cirúrgico e tracionamento ortodôntico ancorado no disjuntor maxilar. Resultado: O desfecho do tratamento foi satisfatório, visto que o dente incluso foi reposicionado e a má oclusão da paciente foi corrigida. Conclusão: O tracionamento ortocirúrgico de incisivo superior permanente com dilaceração radicular é desafiador e com prognóstico incerto. Contudo, seu reposicionamento é possível quando se realiza um diagnóstico, planejamento periodontal e biomecânico adequado (AU)

Abstract Introduction: Dental trauma in the primary dentition can influence the development of permanent successors and cause a displacement of the crown in relation to the dental root, generating a curvature defined as laceration, which in most cases prevents the normal eruption of the permanent tooth. There are several treatment possibilities, from extraction to orthosurgical treatment. Objective: The present study aims to report a clinical case of a left upper central incisor (21) with root laceration whose treatment involved a surgical procedure and orthodontic traction anchored in the maxillary breaker. Result: The treatment outcome was satisfactory, since the included tooth was repositioned and the patients' malocclusion was corrected. Conclusion: Orthosurgical traction of the permanent upper incisor with root dilaceration is challenging and has an uncertain prognosis. However, its repositioning is possible when a diagnosis, periodontal and biomechanical planning is performed.(AU)

Effect of local injection of injectable platelet-rich fibrin on bone remodeling during orthodontic tooth movement in dogs.

Background: This study aimed to assess the effect of local injection of injectable platelet-rich fibrin (i-PRF) on bone remodeling during orthodontic tooth movement in dogs. Materials and Methods: In this animal study, the maxillary first premolars of four adult male mixed-breed dogs were bilaterally extracted, and a nickel-titanium closed coil spring with 150 g force was placed between the canine and second premolar teeth. One quadrant of the maxilla was randomly selected as the test quadrant, and 0.5 cc i-PRF was injected into the periodontal ligament (PDL) around the second premolar at 1, 21, and 42 days. The other quadrant served as the control group and received saline injections. The dogs were sacrificed after 63 days, histological sections were prepared, and changes in bone remodeling were assessed by comparing the percentage of osteogenesis and number of osteoblasts and osteoclasts between the two groups by the Wilcoxon and Mann-Whitney U-tests (α = 0.05). Results: The percentage of osteogenesis (16.0% ± 4.96% in i-PRF and 13.5% ± 4.43% in the control), the percentage of newly formed lamellar bone (10.25% ± 2.87% in i-PRF and 8.75% ± 2.36% in the control), the percentage of woven bone (5.75% ± 2.21% in i-PRF and 4.75% ± 2.36% in the control), the number of osteoblasts (15.0 ± 3.46 in i-PRF and 11.75 ± 2.36 in the control), and the number of osteoclasts (11.25 ± 4.34 in i-PRF and 6.25 ± 2.62 in the control) were not significantly different between the two groups (P > 0.05). Conclusion: PDL injection of i-PRF around the second premolars of dogs under orthodontic force had no significant effect on bone remodeling.