4-Year Follow-Up After Transcatheter Tricuspid Valve Replacement Using the EVOQUE System.

Transcatheter tricuspid valve replacement (TTVR) is an increasingly used treatment technique for patients with severe tricuspid regurgitation (TR). Currently, available data from international registries and randomized controlled trials provide outcome data until a maximum follow-up of 2 years after the procedure. This case report presents 4-year follow-up data for an 84-year-old woman who underwent TTVR for torrential TR in 2019. The patient experienced durable TR reduction, symptomatic improvement, right ventricular reverse remodeling, and substantial improvement in liver and kidney function.

The Diagnosis and Treatment of Tricuspid Regurgitation.

BACKGROUND: It is estimated that 6% of persons over age 75 have clinically relevant tricuspid regurgitation (TR). This condition carries a high mortality and is of particular interest because of the recent development of new interventional treatments. METHODS: This review is based on publications that were retrieved by a selective search in the PubMed database for randomized controlled trials (RCTs), observational studies, registry studies, expert recommendations, and current international guidelines. RESULTS: The evidence reveals that TR is an independent cause of mortality. Mortality is correlated with the severity of TR: approximately 35% of patients with severe TR and right heart failure die within 1 year, and about 60% within 3 years. The clinical course varies depending on the etiology (primary TR, atrial/ventricular secondary TR, association with pacemaker systems). In the outpatient setting, timely diagnosis by transthoracic echocardiography is crucial. The options for pharmacotherapy are essentially limited to diuretic treatment (grade 2a recommendation). Early referral to a specialized heart valve center is essential for the prevention of irreversible damage of the right heart and secondary end-organ damage, including cardiohepatic and cardiorenal syndromes. In the heart valve center, an extended diagnostic evaluation with multimodal imaging is followed by a case discussion by the interdisciplinary cardiac team, with individual evaluation of the treatment options. The first randomized controlled trial of treatment for TR yielded a win ratio of 1.48 (95% confidence interval, [1.06; 2.13]) for interventional treatment (edge-to-edge repair) compared to optimal medical therapy. CONCLUSION: As the understanding of tricuspid regurgitation improves, strategies for its interventional treatment are undergoing steady development, with the aim of lowering the mortality of this condition.

Southern Ocean drives multidecadal atmospheric CO2 rise during Heinrich Stadials.

The last glacial period was punctuated by cold intervals in the North Atlantic region that culminated in extensive iceberg discharge events. These cold intervals, known as Heinrich Stadials, are associated with abrupt climate shifts worldwide. Here, we present CO2 measurements from the West Antarctic Ice Sheet Divide ice core across Heinrich Stadials 2 to 5 at decadal-scale resolution. Our results reveal multi-decadal-scale jumps in atmospheric CO2 concentrations within each Heinrich Stadial. The largest magnitude of change (14.0 ± 0.8 ppm within 55 ± 10 y) occurred during Heinrich Stadial 4. Abrupt rises in atmospheric CO2 are concurrent with jumps in atmospheric CH4 and abrupt changes in the water isotopologs in multiple Antarctic ice cores, the latter of which suggest rapid warming of both Antarctica and Southern Ocean vapor source regions. The synchroneity of these rapid shifts points to wind-driven upwelling of relatively warm, carbon-rich waters in the Southern Ocean, likely linked to a poleward intensification of the Southern Hemisphere westerly winds. Using an isotope-enabled atmospheric circulation model, we show that observed changes in Antarctic water isotopologs can be explained by abrupt and widespread Southern Ocean warming. Our work presents evidence for a multi-decadal- to century-scale response of the Southern Ocean to changes in atmospheric circulation, demonstrating the potential for dynamic changes in Southern Ocean biogeochemistry and circulation on human timescales. Furthermore, it suggests that anthropogenic CO2 uptake in the Southern Ocean may weaken with poleward strengthening westerlies today and into the future.

Residual tricuspid regurgitation after tricuspid transcatheter edge-to-edge repair: Insights into the EuroTR registry.

AIMS: Data on the prognostic impact of residual tricuspid regurgitation (TR) after tricuspid transcatheter edge-to-edge repair (T-TEER) are scarce. The aim of this analysis was to evaluate 2-year survival and symptomatic outcomes of patients in relation to residual TR after T-TEER. METHODS AND RESULTS: Using the large European Registry of Transcatheter Repair for Tricuspid Regurgitation (EuroTR registry) we investigated the impact of residual TR on 2-year all-cause mortality and New York Heart Association (NYHA) functional class at follow-up. The study further identified predictors for residual TR ≥3+ using a logistic regression model. The study included a total of 1286 T-TEER patients (mean age 78.0 ± 8.9 years, 53.6% female). TR was successfully reduced to ≤1+ in 42.4%, 2+ in 40.0% and 3+ in 14.9% of patients at discharge, while 2.8% remained with TR ≥4+ after the procedure. Residual TR ≥3+ was an independent multivariable predictor of 2-year all-cause mortality (hazard ratio 2.06, 95% confidence interval 1.30-3.26, p = 0.002). The prevalence of residual TR ≥3+ was four times higher in patients with higher baseline TR (vena contracta >11.1 mm) and more severe tricuspid valve tenting (tenting area >1.92 cm2). Of note, no survival difference was observed in patients with residual TR ≤1+ versus 2+ (76.2% vs. 73.1%, p = 0.461). The rate of NYHA functional class ≥III at follow-up was significantly higher in patients with residual TR ≥3+ (52.4% vs. 40.5%, p < 0.001). Of note, the degree of TR reduction significantly correlated with the extent of symptomatic improvement (p = 0.012). CONCLUSIONS: T-TEER effectively reduced TR severity in the majority of patients. While residual TR ≥3+ was associated with worse outcomes, no differences were observed for residual TR 1+ versus 2+. Symptomatic improvement correlated with the degree of TR reduction.

Right ventricular to pulmonary artery coupling in patients with different types of aortic stenosis undergoing TAVI.

BACKGROUND: Right ventricular (RV) dysfunction in patients undergoing transcatheter aortic valve implantation (TAVI) for aortic stenosis (AS) has long been disregarded. We aimed to assess the predictive value of RV to pulmonary artery coupling (RV/PAc), defined as tricuspid annular plane systolic excursion to systolic pulmonary artery pressure, on mortality in different flow types of AS after TAVI. METHODS: All patients undergoing TAVI for AS at our centre between 2018 and 2020 were assessed; 862 patients were analysed. The cohort was dichotomized using a ROC analysis (cut-off 0.512 mm/mmHg), into 429 patients with preserved and 433 patients with reduced RV/PAc. RESULTS: Reduced RV/PAc was associated with male sex and a higher rate of comorbidities. Short-term VARC-3 endpoints and NYHA classes at follow-up were comparable. Reduced RV/PAc was associated with higher 2-year all-cause mortality (35.0% [30.3-39.3%] vs. 15.4% [11.9-18.7%], hazard ratio 2.5 [1.9-3.4], p < 0.001). Cardiovascular mortality was almost tripled. Results were consistent after statistical adjustment and in a multivariate model. Sub-analyses of AS flow types revealed lower RV/PAc in classical and paradoxical low-flow low-gradient AS, with the majority having reduced RV/PAc (74% and 59%). RV/PAc retained its predictive value in these subgroups. CONCLUSIONS: RV dysfunction defined by low RV/PAc is a strong mortality predictor after TAVI independent of flow group. It should be incorporated in future TAVI risk assessment.

[Clinical aspects and treatment of tricuspid valve regurgitation]. / Klinik und Therapie der Trikuspidalklappeninsuffizienz.

Tricuspid regurgitation (TR) leading to right heart failure is prevalent and associated with increased mortality. The significant under-recognition of the disease resulted from insufficient medical therapies and the high associated risk of surgical therapy. Over the last decade there has been a rapid development of interventional treatment options so that the disease has increasingly become the focus of attention of specialists in internal medicine and interventional cardiologists. The etiology of TR is differentiated into primary TR, secondary atrial TR, secondary ventricular TR and TR associated with cardiac implantable electronic devices (CIED). The TR was identified as an independent predictor of mortality, independent of associated diseases such as atrial fibrillation, left-sided heart failure or pulmonary hypertension. Even patients with low to moderate TR have a significantly increased risk of mortality. Early diagnostics and estimation of the severity by echocardiography as well as timely referral to a tertiary heart valve center are decisive in order to evaluate possible treatment options before irreversible right ventricular damage and secondary organ dysfunction occur. For transcatheter edge-to-edge repair and transcatheter tricuspid valve replacement there is now first evidence from randomized controlled studies. While the understanding of TR is continuously improving, new tricuspid valve repair and replacement systems are in a state of steady progress. Whether the treatment has an effect on reduction of the mortality and stabilization of right ventricular failure with a reduction in hospitalization, will first be shown in future studies.

Congestion patterns in severe tricuspid regurgitation and transcatheter treatment: Insights from a multicentre registry.

AIMS: While invasively determined congestion holds mechanistic and prognostic significance in acute heart failure (HF), its role in patients with tricuspid regurgitation (TR)-related right- heart failure (HF) undergoing transcatheter tricuspid valve intervention (TTVI) is less well established. A comprehensive understanding of congestion patterns might aid in procedural planning, risk stratification, and the identification of patients who may benefit from adjunctive therapies before undergoing TTVI. The aim of this study was to investigate the role of congestion patterns in patients with severe TR and its implications for TTVI. METHODS AND RESULTS: Within a multicentre, international TTVI registry, 813 patients underwent right heart catheterization (RHC) prior to TTVI and were followed up to 24 months. The median age was 80 (interquartile range 76-83) years and 54% were women. Both mean right atrial pressure (RAP) and pulmonary capillary wedge pressure (PCWP) were associated with 2-year mortality on Cox regression analyses with Youden index-derived cut-offs of 17 mmHg and 19 mmHg, respectively (p < 0.01 for all). However, RAP emerged as an independent predictor of outcomes following multivariable adjustments. Pre-interventionally, 42% of patients were classified as euvolaemic (RAP <17 mmHg, PCWP <19 mmHg), 23% as having left-sided congestion (RAP <17 mmHg, PCWP ≥19 mmHg), 8% as right-sided congestion (RAP ≥17 mmHg, PCWP <19 mmHg), and 27% as bilateral congestion (RAP ≥17 mmHg, PCWP ≥19 mmHg). Patients with right-sided or bilateral congestion had the lowest procedural success rates and shortest survival times. Congestion patterns allowed for discerning specific patient's physiology and specifying prognostic implications of right ventricular to pulmonary artery coupling surrogates. CONCLUSION: In this large cohort of invasively characterized patients undergoing TTVI, congestion patterns involving right-sided congestion were associated with low procedural success and higher mortality rates after TTVI. Whether pre-interventional reduction of right-sided congestion can improve outcomes after TTVI should be established in dedicated studies.

Ten Future Challenges in the Field of Transcatheter Mitral Valve Edge-to-Edge Repair.

Mitral valve transcatheter edge-to-edge repair (M-TEER) and replacement (TMVR) have evolved as guideline-recommended treatment approaches for mitral regurgitation (MR). Even though they are supported by a growing body of evidence from either randomized trials or large registries, there are still several unsolved challenges in the field of interventional MR treatment. In the present review, we discuss the ten most important open questions regarding M-TEER and TMVR.

Atrial Functional Tricuspid Regurgitation in Patients Undergoing Transcatheter Aortic Valve Replacement.

BACKGROUND: Knowledge about atrial functional tricuspid regurgitation (afTR) in transcatheter aortic valve replacement (TAVR) patients is scarce. OBJECTIVES: The aim of the study was to analyze the association between the entity and the development of tricuspid regurgitation (TR) in patients undergoing TAVR for aortic stenosis and concomitant TR. METHODS: We analyzed patients undergoing TAVR for severe aortic stenosis from January 2013 to December 2020 and concomitant at least moderate TR at baseline. afTR was defined as enlargement of the right atrium in relation to the right ventricle. TR development after TAVR and 3-year all-cause mortality were evaluated. RESULTS: Out of 3,474 TAVR patients, we identified 420 patients with concomitant at least moderate TR. A total of 363 patients were included in the study, with 178 patients stratified in the afTR and 185 in the non-afTR group based on a receiver-operating characteristic curve cutoff of 1.132 of the right atrial/right ventricular area ratio. TR improvement after TAVR was observed in significantly less patients with afTR compared with non-afTR (31.1% vs 60.6%; P < 0.001). Multivariate regression analysis confirmed afTR as independent predictor for TR persistence (adjusted OR: 2.80; 95% CI: 1.66-4.76; P < 0.001). Moreover, afTR was associated with aggravation of TR after TAVR (17.0% vs 6.8%; P = 0.013). Three-year all-cause mortality was significantly higher in patients with persistence compared with patients with improvement of TR (P < 0.001). CONCLUSIONS: In TAVR patients, afTR is an independent predictor for TR persistence. Moreover, TR persistence is associated with increased 3-year all-cause mortality.

Nationwide USA re-analysis of amplicon metabarcoding targeting ß-tubulin isoform-1 reveals absence of benzimidazole resistant SNPs in Ancylostoma braziliense, Ancylostoma tubaeforme and Uncinaria stenocephala.

Nationwide sampling by Venkatesan and colleagues (2023) described the resistance status of the canine hookworm, Ancylostoma caninum, to benzimidazoles across the USA via ß-tubulin isotype-1 amplicon metabarcoding. In this study, we aimed to use the existing public amplicon metabarcoding data and mine it for the presence of ß-tubulin isotype-1 sequences that belong to hookworm species other than A. caninum. Through bioinformatics analysis we assigned species to A. caninum, Ancylostoma braziliense, Ancylostoma tubaeforme and Uncinaria stenocephala. All non-A. caninum sequences contained only the benzimidazole susceptible residues of ß-tubulin isotype-1. Using two ß-tubulin isotype-1 metabarcoding sequence data (assay targeting 134 and 167 codons, and assay targeting 198 and 200 codons), 2.0% (6/307) and 2.9% (9/310) individual samples had hookworms other than A. caninum (A. braziliense n = 5, A. tubaeforme n = 4 and U. stenocephala n = 2), respectively. We identified one sample containing A. braziliense in each of the Northeastern region and Midwestern region, and in three samples from the Southern region. Presence of A. tubaeforme in dog faeces is considered as pseudoparasitism. There were no statistically significant regional differences for the distribution of each species, for either of the two assays independently or combined (χ2 tests, P > 0.05). Our work demonstrates the utility of the amplicon metabarcoding for the identification of species through antemortem assays, thus resolving the dilemma of assigning hookworm species based on either post-mortem or egg sizes for the identification of hookworms.

Artificial intelligence-enabled assessment of right ventricular to pulmonary artery coupling in patients undergoing transcatheter tricuspid valve intervention.

AIMS: Right ventricular to pulmonary artery (RV-PA) coupling has been established as a prognostic marker in patients with severe tricuspid regurgitation (TR) undergoing transcatheter tricuspid valve interventions (TTVI). RV-PA coupling assesses right ventricular systolic function related to pulmonary artery pressure levels, which are ideally measured by right heart catheterization. This study aimed to improve the RV-PA coupling concept by relating tricuspid annular plane systolic excursion (TAPSE) to mean pulmonary artery pressure (mPAP) levels. Moreover, instead of right heart catheterization, this study sought to employ an extreme gradient boosting (XGB) algorithm to predict mPAP levels based on standard echocardiographic parameters. METHODS AND RESULTS: This multicentre study included 737 patients undergoing TTVI for severe TR; among them, 55 patients from one institution served for external validation. Complete echocardiography and right heart catheterization data were available from all patients. The XGB algorithm trained on 10 echocardiographic parameters could reliably predict mPAP levels as evaluated on right heart catheterization data from external validation (Pearson correlation coefficient R: 0.68; P value: 1.3 × 10-8). Moreover, predicted mPAP (mPAPpredicted) levels were superior to echocardiographic systolic pulmonary artery pressure (sPAPechocardiography) levels in predicting 2-year mortality after TTVI [area under the curve (AUC): 0.607 vs. 0.520; P value: 1.9 × 10-6]. Furthermore, TAPSE/mPAPpredicted was superior to TAPSE/sPAPechocardiography in predicting 2-year mortality after TTVI (AUC: 0.633 vs. 0.586; P value: 0.008). Finally, patients with preserved RV-PA coupling (defined as TAPSE/mPAPpredicted > 0.617 mm/mmHg) showed significantly higher 2-year survival rates after TTVI than patients with reduced RV-PA coupling (81.5% vs. 58.8%, P < 0.001). Moreover, independent association between TAPSE/mPAPpredicted levels and 2-year mortality after TTVI was confirmed by multivariate regression analysis (P value: 6.3 × 10-4). CONCLUSION: Artificial intelligence-enabled RV-PA coupling assessment can refine risk stratification prior to TTVI without necessitating invasive right heart catheterization. A comparison with conservatively treated patients is mandatory to quantify the benefit of TTVI in accordance with RV-PA coupling.

Applying the TRILUMINATE Eligibility Criteria to Real-World Patients Receiving Tricuspid Valve Transcatheter Edge-to-Edge Repair.

BACKGROUND: According to the TRILUMINATE (Clinical Trial to Evaluate Cardiovascular Outcomes in Patients Treated With the Tricuspid Valve Repair System) trial, transcatheter tricuspid edge-to-edge repair (T-TEER) improves quality of life beyond medical treatment, while no effects on heart failure hospitalization (HFH) and survival were observed at 1 year. However, the generalizability of the TRILUMINATE trial to real-world conditions remains a subject of discussion. OBJECTIVES: The aim of this study was to apply the clinical TRILUMINATE inclusion and exclusion criteria to a real-world T-TEER patient group and evaluate symptomatic and survival outcome in TRILUMINATE-eligible and TRILUMINATE-ineligible patients. METHODS: Clinical TRILUMINATE inclusion and exclusion criteria were applied to a cohort of patients who underwent T-TEER at 5 European centers from 2016 to 2022. Study patients were compared regarding baseline characteristics, survival, HFH, and symptomatic outcomes as measured by NYHA functional class, a quality-of-life questionnaire and 6-minute walk distance. RESULTS: Of 962 patients, 54.8% were classified as TRILUMINATE eligible, presenting with superior left ventricular function and fewer comorbidities compared with the ineligible population. Tricuspid regurgitation reduction, improvement in NYHA functional class, quality of life, and exercise capacity were comparable in both groups. However, the 1-year survival and HFH rates significantly differed (tricuspid regurgitation ≤2+ at discharge, 82% vs 85%; survival, 85% vs 75%; HFH, 14% vs 22% for eligible vs ineligible patients). CONCLUSIONS: The observed differences in survival and HFH outcomes suggest a limited generalizability of TRILUMINATE to real-world conditions and indicate the need for additional studies evaluating the outcomes after T-TEER in less selected patient populations.

Comparison of balanced and unbalanced crystalloids as resuscitation fluid in patients treated for cardiogenic shock.

BACKGROUND: The efficacy and safety of saline versus balanced crystalloid solutions in ICU-patients remains complicated by exceptionally heterogenous study population in past comparative studies. This study sought to compare saline and balanced crystalloids for fluid resuscitation in patients with cardiogenic shock with or without out-of-hospital cardiac arrest (OHCA). METHODS: We retrospectively analyzed 1032 propensity score matched patients with cardiogenic shock from the Munich University Hospital from 2010 to 2022. In 2018, default resuscitation fluid was changed from 0.9% saline to balanced crystalloids. The primary endpoint was defined as 30-day mortality rate. RESULTS: Patients in the saline group (n = 516) had a similar 30-day mortality rate as patients treated with balanced crystalloids (n = 516) (43.1% vs. 43.0%, p = 0.833), but a higher incidence of new onset renal replacement therapy (30.2% vs 22.7%, p = 0.007) and significantly higher doses of catecholamines. However, OHCA-patients with a lactate level higher than 7.4 mmol/L had a significantly lower 30-day mortality rate when treated with saline (58.6% vs. 79.3%, p = 0.013). In addition, use of balanced crystalloids was independently associated with a higher mortality in the multivariate cox regression analysis after OHCA (hazard ratio 1.43, confidence interval: 1.05-1.96, p = 0.024). CONCLUSIONS: In patients with cardiogenic shock, use of balanced crystalloids was associated with a similar all-cause mortality at 30 days but a lower rate of new onset of renal replacement therapy. In the subgroup of patients after OHCA with severe shock, use of balanced crystalloids was associated with a higher mortality than saline. TRIAL REGISTRATION: LMUshock registry (WHO International Clinical Trials Registry Platform Number DRKS00015860).

Force-Controlled Biomechanical Simulation of Orthodontic Tooth Movement with Torque Archwires Using HOSEA (Hexapod for Orthodontic Simulation, Evaluation and Analysis).

This study aimed to investigate the dynamic behavior of different torque archwires for fixed orthodontic treatment using an automated, force-controlled biomechanical simulation system. A novel biomechanical simulation system (HOSEA) was used to simulate dynamic tooth movements and measure torque expression of four different archwire groups: 0.017″ x 0.025″ torque segmented archwires (TSA) with 30° torque bending, 0.018″ x 0.025″ TSA with 45° torque bending, 0.017″ x 0.025″ stainless steel (SS) archwires with 30° torque bending and 0.018″ x 0.025″ SS with 30° torque bending (n = 10/group) used with 0.022″ self-ligating brackets. The Kruskal-Wallis test was used for statistical analysis (p < 0.050). The 0.018″ x 0.025″ SS archwires produced the highest initial rotational torque moment (My) of -9.835 Nmm. The reduction in rotational moment per degree (My/Ry) was significantly lower for TSA compared to SS archwires (p < 0.001). TSA 0.018″ x 0.025″ was the only group in which all archwires induced a min. 10° rotation in the simulation. Collateral forces and moments, especially Fx, Fz and Mx, occurred during torque application. The measured forces and moments were within a suitable range for the application of palatal root torque to incisors for the 0.018″ x 0.025″ archwires. The 0.018″ x 0.025″ TSA reliably achieved at least 10° incisal rotation without reactivation.

Cardio-hepatic syndrome in patients undergoing transcatheter aortic valve replacement.

BACKGROUND: Cardiohepatic syndrome (CHS) has been identified as an important but underrecognized survival predictor in multiple cardiovascular disease entities. The objectives of this study were to evaluate the prevalence and prognostic value of CHS in patients undergoing TAVR for severe aortic stenosis (AS). METHODS: The study included patients with available laboratory parameters of hepatic function who underwent TAVR from July 2013 until December 2019 at our center. CHS was defined as an elevation of at least two of three laboratory cholestasis parameters above the upper limit of normal (bilirubin, alkaline phosphatase, and gamma glutamyl transferase). Study endpoints were three-year survival, technical and device failure (VARC 3), as well as New York Heart Association (NYHA) functional class at follow-up. RESULTS: Among a total of 953 analyzed patients (47.6% females, median age 80.0 [76.0-85.0] years) CHS was present in 212 patients (22.4%). In patients with vs. without CHS, rates of technical (6.1% vs. 8.4%, p = 0.29) and device failure (18.9% vs. 17.3%, p = 0.59) were comparable. NYHA functional class at baseline and follow-up was more severe in patients with CHS. Nevertheless, heart failure symptoms improved from baseline to follow-up irrespective of hepatic function. Three-year survival rates were significantly lower in patients with CHS (49.4 vs. 65.4%, p < 0.001). The predictive value of CHS persisted after adjustment in a multivariable analysis (hazard ratio 1.58, p < 0.01). CONCLUSION: In patients undergoing TAVR, CHS is prevalent in 22% of patients and is associated with increased postinterventional mortality. Thus, CHS should be included in the decision-making process within the TAVR heart team. Cardiohepatic syndrome (CHS) as defined by an elevation of at least two of three laboratory cholestasis parameters above the upper limit of normal was prevalent in 22% of patients undergoing TAVR for severe AS. The presence of CHS was associated with more severe heart failure symptoms and worse three-year survival.

Biomechanical simulation of forces and moments of initial orthodontic tooth movement in dependence on the used archwire system by ROSS (Robot Orthodontic Measurement & Simulation System).

OBJECTIVES: Aim of this study was to determine the forces and moments during simulated initial orthodontic tooth movements using a novel biomechanical test setup. METHODS: The test setup consisted of an industrial precision robot with a force-torque sensor, a maxillary model and a control computer and software. Forces and moments acting on the corresponding experimental tooth during the motion simulations were dynamically measured for two 0.016" NiTi round archwires (Sentalloy Light/Sentalloy Medium). Intrusive (#1), rotational (#2) and angular (#3) tooth movements were simulated by a control program based on the principle of force control and executed by the robot. The results were statistically analysed using K-S-test and Mann-Whitney U test with a significance level of α = 5%. RESULTS: Sentalloy Medium archwires generated higher forces and moments than the Sentalloy Light archwires in all simulations. In simulation #1 the mean initial forces/moments reached 1.442 N/6.781 Nmm for the Light archwires and 1.637 N/9.609 Nmm for the Medium archwires. In movement #2 Light archwires generated mean initial forces/moments of 0.302 N/-8.271 Nmm whereas Medium archwires generated 0.432 N/-9.653 Nmm. Simulation #3 showed mean initial forces/moments of -0.122 N/8.477 Nmm from the Light archwires compared to -0.300 N/11.486 Nmm for the Medium archwires. SIGNIFICANCE: The measured forces and moments were suitable for initial orthodontic tooth movement in simulations #2 and #3, however inadequate in simulation #1. Reduced archwire dimensions (<0.016″) should be selected for initial leveling of vertical malocclusions.

Thermal Programming of Commercially Available Orthodontic NiTi Archwires.

The shape of superelastic Nickel-Titanium (NiTi) archwires can be adjusted with thermal treatments using devices such as the Memory-MakerTM (Forestadent), which potentially affects their mechanical properties. The effect of such treatments on these mechanical properties was simulated by means of a laboratory furnace. Fourteen commercially available NiTi wires (0.018″ × 0.025″) were selected from the manufacturers American Orthodontics, Dentaurum, Forestadent, GAC, Ormco, Rocky Mountain Orthodontics and 3M Unitek. Specimens were heat treated using different combinations of annealing duration (1/5/10 min) and annealing temperature (250-800 °C) and investigated using angle measurements and three-point bending tests. Complete shape adaptation was found at distinct annealing durations/temperatures for each wire ranging between ~650-750 °C (1 min), ~550-700 °C (5 min) and ~450-650 °C (10 min), followed by a loss of superelastic properties shortly afterwards at ~750 °C (1 min), ~600-650 °C (5 min) and ~550-600 °C (10 min). Wire-specific working ranges (complete shaping without loss of superelasticity) were defined and a numerical score (e.g., stable forces) was developed for the three-point bending test. Overall, the wires Titanol Superelastic (Forestadent), Tensic (Dentaurum), FLI CuNiTi27 (Rocky Mountain Orthodontics) and Nitinol Classic (3M Unitek) proved to be the most user-friendly. Thermal shape adjustment requires wire-specific working ranges to allow complete shape acceptance and high scores in bending test performance to ensure permanence of the superelastic behaviour.

Influence of growth structures and fixed appliances on automated cephalometric landmark recognition with a customized convolutional neural network.

BACKGROUND: One of the main uses of artificial intelligence in the field of orthodontics is automated cephalometric analysis. Aim of the present study was to evaluate whether developmental stages of a dentition, fixed orthodontic appliances or other dental appliances may affect detection of cephalometric landmarks. METHODS: For the purposes of this study a Convolutional Neural Network (CNN) for automated detection of cephalometric landmarks was developed. The model was trained on 430 cephalometric radiographs and its performance was then tested on 460 new radiographs. The accuracy of landmark detection in patients with permanent dentition was compared with that in patients with mixed dentition. Furthermore, the influence of fixed orthodontic appliances and orthodontic brackets and/or bands was investigated only in patients with permanent dentition. A t-test was performed to evaluate the mean radial errors (MREs) against the corresponding SDs for each landmark in the two categories, of which the significance was set at p < 0.05. RESULTS: The study showed significant differences in the recognition accuracy of the Ap-Inferior point and the Is-Superior point between patients with permanent dentition and mixed dentition, and no significant differences in the recognition process between patients without fixed orthodontic appliances and patients with orthodontic brackets and/or bands and other fixed orthodontic appliances. CONCLUSIONS: The results indicated that growth structures and developmental stages of a dentition had an impact on the performance of the customized CNN model by dental cephalometric landmarks. Fixed orthodontic appliances such as brackets, bands, and other fixed orthodontic appliances, had no significant effect on the performance of the CNN model.