Cusp Height Research Articles

Development of a correction coefficient for radiographic evaluation of the alveolar bone crest: a pilot study.

To analyze the differences in cusp height on radiographs, establishing proportional relationships between cusp and alveolar bone crest (ABC) measurements. The goal of this study was to develop a correction coefficient by considering this proportion. Twenty-one artificial teeth, molars and premolars, and bovine ribs were used. Interproximal radiographs were taken with the aid of a positioner. The vertical angles used were: 0°, + 5°, and + 10°, and processed using three spatial resolutions measured in line pairs per mm (lp/mm): 20, 25 and 40. The Perio filter was applied to each image, in addition to the original one. Combinations of angle, resolution, and filter were made. Eighteen images were analyzed by three specialists, resulting in 252 measurements for each evaluator, totaling 756 measurements. The overall variability of the measurements can be explained mainly by the variation in tooth anatomy. The 0° 25 lp/mm Perio filter method was the closest one to the actual clinical scenario for both cusps and ABC. The correction factor managed to explain 71.45% of the errors. The variation in vertical angulation interferes with cusp and ABC measurements, and the angulation at 0º and spatial resolution of 25 lp/mm showed better results. The use of correction coefficients allowed approaching actual measurement values. More accurate ABC height measurements are essential even in radiographic exams that do not meet the standard of excellence because the need to repeat radiographic exams is then eliminated.

Testing the patterning cascade model of cusp development in Macaca fascicularis mandibular molars

ObjectiveMolar crown configuration plays an important role in systematics, and functional and comparative morphology. In particular, the number of cusps on primate molars is often used to identify fossil species and infer their phylogenetic relationships. However, this variability deserves renewed consideration as a number of studies now highlight important developmental mechanisms that may be responsible for the presence of molar cusps in some mammalian taxa. Experimental studies of rodent molars suggest that cusps form under a morphodynamic, patterning cascade model of development (PCM) that involve the iterative formation of enamel knots. This model posits that the size, shape and location of the first-forming cusps determines the presence and positioning of later-forming cusps. DesignHere we test whether variation in accessory cusp presence in 13 Macaca fascicularis mandibular second molars (M2s) is consistent with predictions of the PCM. Using micro-CT, we imaged these M2s and employed geometric morphometrics to examine whether shape variation in the enamel-dentine junction (EDJ) correlates with accessory cusp presence. ResultsWe find that accessory cusp patterning in macaque M2s is broadly consistent with the PCM. Molars with accessory cusps were larger in size and possessed shorter relative cusp heights compared to molars without accessory cusps. Peripheral cusp formation was also associated with more centrally positioned primary cusps, as predicted by the PCM. ConclusionsWhile these results demonstrate that a patterning cascade model is broadly appropriate for interpreting cusp variation in Macaca fascicularis molars, it does not explain all manifestations of accessory cusp expression in this sample.

Mesh Optimisation for General 3D Printed Objects with Cusp-Height Triangulation Approach

3D printing (3DP) is increasingly utilized to achieve quick turnaround on various geometric designs and prototypes, being the growing part of additive manufacturing technology (AMT). The 3DP technique effectively improves the production of complex models in terms of low-cost, time-consuming production, and with less material volume. The key to results optimisation with 3DP is the preparation of the geometry. The following techniques can effectively reduce the required time of the 3D printing process for complex and non-linear CAD files. The fused deposition modelling/fabrication (FDM/FFF) techniques become the first choice in many applications, including biomedical ones. Still, some obstacles exist in the geometry roughness and quality zones. This paper proposes an optimisation method for 3D printed shapes used in biomedical devices and instrumentation by minimising the support structure attached to the model using the FDM technique. In this research, we proposed a method for dynamic compensation against gravity-affected parts extended from the main object’s geometry using a forward planar learning (FPL) algorithm to minimise cusp height in 3D printed objects. After the slicing stage, the outcomes proved to be of good quality, optimised the object’s surfaces, and minimised the printing time by 32%–38%. The proposed method is promising in defining a better setting for slicing and toolpath for FDM 3D printing. However, this method was not tested on other 3DP methods (Stereolithography (SLA), Selective laser sintering (SLS), and Digital Light Processing (DLP)), as more verification efforts need to be done on these 3D printing processes.

Transcription factor activator protein 2C contribute to molar development in mice

Objective: Explore the expression pattern of transcription factor activator protein 2C (TFAP2C) and identify the roles of Tfap2c during tooth development. Methods: Real-time fluorescence quantitative PCR (RT-qPCR) was used to analyze the relative expression level of Tfap2c in various organs of embryonic day(E)14.5 mouse embryos and mouse molar germs at E12.5-E18.5 and postnatal day (P)0-P7. The expression position of Tfap2c in mouse molar germs was demonstrated by frozen section immunofluorescence staining. Cultured mandibular molar germs were transfected with control small interfering RNA (siRNA) or Tfap2c siRNA to evaluate the effect of Tfap2c on tooth molar germs development, and RT-qPCR was used to detect the relative expression level of genes related to odontoblast expression. Dental mesenchymal cells were isolated from E14.5 molar germs and transfected with control siRNA or Tfap2c siRNA, cell counting kit 8 (CCK-8) and scratch healing test were applied to detect dental mesenchymal cell viability and migration. Results: Tfap2c was highly expressed in the early development period of mouse molar germs. Tfap2c was expressed in the epithelial and mesenchymal tissues of E13.5 mouse molar germs and there was no significant difference of relative expression of Tfap2c between them (t=1.06, P=0.472). Tfap2c was expressed in mesenchymal tissues of E14.5 mouse molar germs and the relative expression of Tfap2c in mesenchymal tissues was significantly higher than epithelial tissues (t=37.29, P<0.0001). For molar germs transfected with Tfap2c siRNA, the relative height of cusps (0.708±0.171) and the ratio of cusp height and crown height (0.321±0.068) was significantly lower than control group (1.000±0.287 and 0.483±0.166) (t=2.79, P=0.012; t=2.85, P=0.015). But there was no significant difference in relative height (1.078±0.206, 0.993±0.254, t=0.83, P=0.419)and relative width (1.000±0.116, 0.999±0.122, t=0.01, P=0.992) of crowns between two groups. The relative expression level of genes related to odontoblast expression was decreased (Dspp: t=15.33, P<0.001; Dmp1: t=13.81, P<0.001). Tfap2c siRNA hinders cell migration in dental mesenchymal cells (t=29.86, P=0.001), but there was no significant difference in CCK-8 absorbance value between two groups. The relative expression level of genes related to odontoblast expression was also decreased in dental mesenchymal cells transfected with Tfap2c siRNA (Dspp: t=3.86, P=0.031; Dmp1; t=4.36, P=0.022). Conclusions: Tfap2c highly expressed in the early morphogenesis period of mouse molar germs, mainly in mesenchymal tissues. Tfap2c affected the cusps formation of mouse molar germs and migration of dental mesenchymal cells.

Performance and failure modes of continuous fibre-reinforced energy absorption tubes by cylindrical layered 3D printing

ABSTRACT Precisely controlling the distribution of continuous fibres on a cylindrical surface is crucial for manufacturing high-performance continuous fibre-reinforced composite (CFRC) tubular structures. Existing manufacturing processes are complex, hindering the regulation of fibre orientation and content. Therefore, this study achieved unrestricted control of 3D-printed continuous fibres in terms of content and arbitrary orientation on a cylindrical surface using a cylindrical layered path planning strategy. The study investigated the impact of different fibre orientations and printing parameters on the compressive performance and energy absorption of 3D-printed CFRC tubes under quasi-static axial compression by analysing fibre distribution and failure modes. Compared to the flat layered printing strategy, the cylindrical layered printing strategy showed significant increases in compressive strength and energy absorption, by 44.3% and 85.2%, respectively. A cusp height analysis model demonstrated that the cylindrical layered printing strategy significantly enhances forming accuracy compared to the conventional flat layered method. The CFRC lightweight energy absorption tubes fabricated with this strategy demonstrated the viability of the manufacturing process. This new manufacturing technology has significant potential for producing high-performance and high-precision CFRC energy absorption tubes, applicable in aeronautics and astronautics.

1040 Morphometric Study of Human Aortic Valve Along with a Case of Bicuspid Aortic Valve in Cadaver

Abstract Aim The morphometric data pertaining to the aortic valve is very relevant for aortic valvular diseases and prosthetic valve transplant thereof, but such data is variably described in autopsy studies which prompted us to study the same in cadaveric hearts of Indian population. We also present a case of symmetrical bicuspid aortic valve (BAV). Method Thirty formalin fixed cadaveric hearts of both genders, aged between 58 -83 years were taken. Guidelines for using cadaver for teaching and research were followed. Various attributes of the aortic valve viz. number, width and height of cusps, number and depth of aortic sinuses, number of coronary ostia were recorded. All measurements were made with Vernier callipers and statistical analysis was performed with Microsoft Excel version 2019. Results The mean cusp heights were 18.28±0.54 mm, 19.52±0.34 mm and 20.91±0.46 mm respectively for the right, left and the non-coronary cusps. The mean depths of the aortic sinuses were 17.3±0.68 mm, 16.8±0.74 mm and 15.9±0.32 mm respectively for the right, left and the non-coronary sinus. We also observed symmetrical BAV in 1 (2.5%) out of the 30 specimens but the death of the individual was unrelated to the presence of the anomaly. Conclusions The morphometric parameters obtained in the study would help in transplanting prosthetic aortic valve with greater compatibility. The chance of encountering congenital BAV even in individuals with no cardiac ailment should be borne in mind.

Deep learning-designed implant-supported posterior crowns: Assessing time efficiency, tooth morphology, emergence profile, occlusion, and proximal contacts

ObjectivesTo compare implant supported crowns (ISCs) designed using deep learning (DL) software with those designed by a technician using conventional computer-aided design software. MethodsTwenty resin-based partially edentulous casts (maxillary and mandibular) used for fabricating ISCs were evaluated retrospectively. ISCs were designed using a DL-based method with no modification of the as-generated outcome (DB), a DL-based method with further optimization by a dental technician (DM), and a conventional computer-aided design method by a technician (NC). Time efficiency, crown contour, occlusal table area, cusp angle, cusp height, emergence profile angle, occlusal contacts, and proximal contacts were compared among groups. Depending on the distribution of measured data, various statistical methods were used for comparative analyses with a significance level of 0.05. ResultsISCs in the DB group showed a significantly higher efficiency than those in the DM and NC groups (P ≤ 0.001). ISCs in the DM group exhibited significantly smaller volume deviations than those in the DB group when superimposed on ISCs in the NC group (DB–NC vs. DM–NC pairs, P ≤ 0.008). Except for the number and intensity of occlusal contacts (P ≤ 0.004), ISCs in the DB and DM groups had occlusal table areas, cusp angles, cusp heights, proximal contact intensities, and emergence profile angles similar to those in the NC group (P ≥ 0.157). ConclusionsA DL-based method can be beneficial for designing posterior ISCs in terms of time efficiency, occlusal table area, cusp angle, cusp height, proximal contact, and emergence profile, similar to the conventional human-based method. Clinical significanceA deep learning-based design method can achieve clinically acceptable functional properties of posterior ISCs. However, further optimization by a technician could improve specific outcomes, such as the crown contour or emergence profile angle.

Analysis of changes and correlation in condyle-fossa relationship after maxillary skeletal expansion.

To investigate the changes in condyle-glenoid fossa relationship after maxillary skeletal expansion (MSE) and to verify the correlation between the condyle positional changes and expansion effect. In this study, 20 patients (mean age 21.1 ± 5.7 years, 8 male, 12 female) with maxillary transverse deficiency (MTD) were treated with the MSE appliance, which contained molar bands and a expander with four micro-implants. The CBCT images were taken before expansion (T0), after expansion (T1) and after 6 months of maintenance (T2). The posterior TMJ space (PS), superior TMJ space (SS), anterior TMJ space, coronal lateral TMJ space (CLS), coronal medial TMJ space (CMS), condyle axis angle, maxillary basal bone width (BWM), inter-molars width, nasal bone width, molar inclination and molar palatal cusp height (U6H) were measured using Dolphin Imaging. At T1, compared with T0, the PS and SS significantly increased by 0.41 mm (P = .008) and 0.3 mm (P = .007). But only the SS significantly increased by 0.21 mm (P = .025) at T2. There was a significant difference of 0.37 mm (left-right, P = .014) between the left and right SS at T0, but no significant difference at T1 and T2. The increased BMW showed weak positive correlations with the change of PS (P = .015) and CMS (P = .031), and the decreased U6H showed weak negative correlations with the change of PS (P = .015) and CLS (P = .031) at T1. The use of MSE led to an increase in the SS and PS, which were weakly correlated with BWM and U6H. But this effect in the TMJ space gradually diminished after 6 months of maintenance, and the symmetry of the condyle-fossa relationship was preserved.

Systematic adjustment of root dimensions to cusp size in aortic valve repair: a computer simulation.

Aortic valve repair requires the creation of a normal geometry of cusps and aortic root. Of the different dimensions, geometric cusp height is the most difficult to change while annular and sinotubular dimensions can be easily modified. The objective of this study was to investigate, by computer simulation, ideal combinations of annular and sinotubular junction size for a given geometric height. Based on a literature review of anatomical data, a computational biomechanics model was generated for a tricuspid aortic valve. We aimed to determine the ideal relationships for the root dimensions, keeping geometric height constant and creating different combinations of the annular and sinotubular junction dimensions. Using this model, 125 virtual anatomies were created, with 25 different combinations of annulus and sinotubular junction. Effective height, coaptation height and mechanical cusp stress were calculated with the valves in closed configuration. Generally, within the analysed range of geometric heights, changes to the annular diameter yielded a stronger impact than sinotubular junction diameter changes for optimal valve configuration. The best results were obtained with the sinotubular junction being 2-4 mm larger than the annulus, leading to higher effective height, normal coaptation height and lower stress. Within the range tested, stenosis did not occur due to annular reduction. In tricuspid aortic valves, the geometric height can be used to predict ideal post-repair annular and sinotubular junction dimensions for optimal valve configuration. Such an ideal configuration is associated with reduced cusp stress.

Comparative Analysis of Morphological and Morphometric Features of Human, Pig, Calf, and Sheep Aortic Valves: A Cross-sectional Study

Introduction: The aortic valve plays a critical role in maintaining unidirectional blood flow from the left ventricle into the aorta, ensuring efficient circulation throughout the body. Comprising three cusps-the left coronary, right coronary, and non-coronary cusps-the intricate anatomy of the aortic valve is essential for its proper function. The scarcity of aortic valve homografts for transplantation has led to increased interest in studying readily available sources for suitable and durable xenografts. Aim: To compare the morphological and morphometric characteristics of the aortic valves in humans with those in pigs, calves, and sheep. Materials and Methods: The present cross-sectional study was conducted over a three-week period in July 2022. Aortic valves were collected from humans, pigs, calves, and sheep. Five human hearts were obtained from the Anatomy Department of Adichunchanagiri Institute of Medical Sciences, BG Nagar. Additionally, five hearts each from calves, pigs, and sheep were obtained from a nearby abattoir. The hearts were then fixed in a 10% formaldehyde solution for approximately 18 hours. All fat and muscle surrounding the aorta were removed, and the aorta with intact valves was dissected. An incision was made between the left coronary and non-coronary aortic cusps to measure the individual cusps. Morphological and morphometric measurements, including annulus diameter, cusp height, commissural distances, and length of the lunula, were taken using a vernier calliper. The obtained values were statistically compared using paired t-test. Results: The mean values of various measurements of human aortic valves were found to be similar to those of pig aortic valves. Both humans and pigs have three aortic cusps, namely the left, right, and non-coronary cusps. The mean diameter of the aortic annulus in humans was 2.18 cm, while in pigs it was 2.28 cm. The height of the left and right cusps in both human and pig aortic valves was approximately 1.6 cm, whereas the height of the non-coronary cusp was 1.64 cm in humans and 1.38 cm in pigs. The external inter-commissural distance of the left cusp was 2.48 cm, and that of the right cusp was 2.58 cm in both humans and pigs. The external inter-commissural distance of the non-coronary cusp was 2.4 cm in humans and 2.36 cm in pigs. The length of the lunula and internal inter-commissural length of the aortic cusps in humans were relatively similar to those in pigs. However, when compared to measurements in cows and sheep, significant variations were observed. Conclusion: The study findings provide valuable insights into the potential suitability of pig aortic valves for xenograft transplantation and their implications for cardiac surgical procedures.

Observations of beach cusp morphodynamics on a composite beach

Substantial volumes of sediment are moved on coarse grained beaches through the formation and destruction of beach cusps, yet the processes governing cusp behaviour remain poorly understood. Here, we combine continuous 2D LiDAR scan data with daily UAV topographic surveys and RGB imagery to provide detailed morphological measurements of beach cusps on a composite beach with the aim to investigate the role of sediment size and tidal stage on cusp behaviour. Rapid changes in cusp height and prominence were observed when storm-eroded gravels were readily transported over relatively impermeable sandy substratum, showing the high-order control that mixed matrix sediments have on this process. Post storm, gravels armoured the swash zone overlaying the sand and were rapidly reworked into horns, with the incipient bays simultaneously experiencing erosion. We provide some of the first field observations to show divergent behaviours occurring simultaneously along the beach as cusps adjust to the new dominant hydrodynamic regime, with some areas experiencing a shortening of cusp wavelength through new horn growth, whilst others contemporaneously experienced wavelength growth through the removal of intermediate horns. Cusp formation was generally more pronounced on the falling tide, but some evidence indicates horns can also be consolidated and grow in relief at some stages of individual rising tides. This research demonstrates how feedback between sediments, morphology and hydrodynamics are key to determining cusp form, with these insights only made possible through the novel combination of LiDAR, UAV, and camera methods to provide sufficient temporal and spatial resolution to resolve key processes.

Risk of Sinus Sequestration During Redo Transcatheter Aortic Valve Implantation: The Prevalence, Predictors, and Risk Stratification

The number of patients undergoing transcatheter aortic valve implantation (TAVI) with the potential for re-intervention is steadily increasing; however, there is a risk of sinus sequestration (SS) during a redo TAVI. The prevalence, predictors, and risk stratification of risk for SS remain uncertain. We analyzed computed tomography acquired from 263 patients who underwent TAVI between 2021 and 2022: balloon-expandable valve (BEV), 71%, and self-expandable valve (SEV), 29%. Patients were considered at risk of SS if they met 1) BEV frame > sino-tubular junction (STJ) or SEV neo-commissure > STJ and 2) valve-to-STJ < 2 mm. The risk of left, right, and any SS in 51%, 50%, and 65%, respectively, which did not differ between BEV and SEV. The predictors of any SS were the height of the left and right coronary cusp (Odds ratio [OR], 0.81 and 0.71; cut-off, 18.6 and 19.2 mm) and STJ minus annulus diameter (OR, 0.65; cut-off, 3.7 mm) in BEV, and STJ diameter (OR, 0.47; cut-off, 27.6 mm) in SEV. The number of predictors stratified the risk of any SS: low risk with BEV, at 0 predictors (14% at risk of SS); intermediate risk, 1 predictor (65%); high risk, 2 or 3 predictors (81% and 95%); low risk with SEV, 0 predictors (33%), vs. high risk, 1 predictor (91%). In conclusion, two-thirds of patients undergoing TAVI were at risk of SS. The height of the coronary cusp and the STJ diameter were associated with, and adequately stratified the risk of SS.

Arl4c is involved in tooth germ development through osteoblastic/ameloblastic differentiation

Murine tooth germ development proceeds in continuous sequential steps with reciprocal interactions between the odontogenic epithelium and the adjacent mesenchyme, and several growth factor signaling pathways and their activation are required for tooth germ development. The expression of ADP-ribosylation factor (Arf)-like 4c (Arl4c) has been shown to induce cell proliferation, and is thereby involved in epithelial morphogenesis and tumorigenesis. In contrast, the other functions of Arl4c (in addition to cellular growth) are largely unknown. Although we recently demonstrated the involvement of the upregulated expression of Arl4c in the proliferation of ameloblastomas, which have the same origin as odontogenic epithelium, its effect on tooth germ development remains unclear. In the present study, single-cell RNA sequencing (scRNA-seq) analysis revealed that the expression of Arl4c, among 17 members of the Arf-family, was specifically detected in odontogenic epithelial cells, such as those of the stratum intermedium, stellate reticulum and outer enamel epithelium, of postnatal day 1 (P1) mouse molars. scRNA-seq analysis also demonstrated the higher expression of Arl4c in non-ameloblast and inner enamel epithelium, which include immature cells, of P7 mouse incisors. In the mouse tooth germ rudiment culture, treatment with SecinH3 (an inhibitor of the ARNO/Arf6 pathway) reduced the size, width and cusp height of the tooth germ and the thickness of the eosinophilic layer, which would involve the synthesis of dentin and enamel matrix organization. In addition, loss-of-function experiments using siRNAs and shRNA revealed that the expression of Arl4c was involved in cell proliferation and osteoblastic cytodifferentiation in odontogenic epithelial cells. Finally, RNA-seq analysis with a gene set enrichment analysis (GSEA) and Gene Ontology (GO) analysis showed that osteoblastic differentiation-related gene sets and/or GO terms were downregulated in shArl4c-expressing odontogenic epithelial cells. These results suggest that the Arl4c-ARNO/Arf6 pathway axis contributes to tooth germ development through osteoblastic/ameloblastic differentiation.

Sharpening the mesowear tool: geometric morphometric analysis of cusp shape and diet in ruminants

Mesowear is a dietary proxy that relates attritive wear and abrasive wear to the shape of worn tooth cusps of ungulates. Traditional mesowear methods categorize cusps according to relief and sharpness. A geometric morphometric approach has the potential to measure shape with higher precision and to discover unrecognized aspects of cusp shape, possibly improving the efficacy of mesowear. We quantified mesowear in extant Ruminantia, using a 2-D semilandmark outline technique on upper second molar metacones generated from photographs. Among the 91 species sampled, 65 were preassigned to dietary categories, browser, grazer, mixed feeder, and frugivore based on substantiated documentation of diet in the wildlife literature. Metacone cusp shape and metacone mesowear score were found to be independent of size. Principal component and discriminant function analyses of Procrustes transformed semilandmark coordinates revealed two diet-related components of cusp shape. The primary component is related to the traditional mesowear variables of cusp height and side steepness. The secondary shape component reveals variation in the mesiodistal symmetry of the metacone and may relate to a proal vector during the power stroke phase or the relative orientation of the cusps with respect to the chewing stroke vector. Discriminant function analysis of semilandmark data accurately classified the diets of species more frequently (67.2%) than the traditional mesowear method (56.1%). The semilandmark data successfully recognized the diets of grazing and browsing species with correct classification rates ranging from 69% to 95%. The diets of frugivorous and mixed feeding species were less frequently correctly recognized (33%–53%). Mixed feeding diets may be more difficult to recognize due to more heterogeneous diets when compared to browsers and grazers. Frugivores are more difficult to recognize because their rounded cusp apices resemble those of mixed feeders and grazers. We conclude that quantitative shape analysis improves the potential of mesowear. When used as a dietary proxy, we anticipate that mesowear analysis will correctly categorize the diets of most species. When misclassifications are made, they may most often be misclassifications of generalist mixed feeders and frugivores as either browsers or grazers.

Coronary Obstruction From TAVR in Native Aortic Stenosis: Development and Validation of Multivariate Prediction Model

BackgroundTranscatheter aortic valve replacement (TAVR)–related coronary artery obstruction prediction remains unsatisfactory despite high mortality and novel preventive therapies. ObjectivesThis study sought to develop a predictive model for TAVR-related coronary obstruction in native aortic stenosis. MethodsPreprocedure computed tomography and fluoroscopy images of patients in whom TAVR caused coronary artery obstruction were collected. Central laboratories made measurements, which were compared with unobstructed patients from a single-center database. A multivariate model was developed and validated against a 1:1 propensity-matched subselection of the unobstructed cohort. ResultsSixty patients with angiographically confirmed coronary obstruction and 1,381 without obstruction were included. In-hospital death was higher in the obstruction cohort (26.7% vs 0.7%; P < 0.001). Annular area and perimeter, coronary height, sinus width, and sinotubular junction height and width were all significantly smaller in the obstructed cohort. Obstruction was most common on the left side (78.3%) and at the level of the coronary artery ostium (92.1%). Coronary artery height and sinus width, but not annulus area, were significant risk factors for obstruction by logistic regression but performed poorly in predicting obstruction. The new multivariate model (coronary obstruction IF cusp height > coronary height, AND virtual valve-to-coronary distance ≤4 mm OR culprit leaflet calcium volume >600 mm3) performed well, with an area under the curve of 0.93 (sensitivity = 0.93, specificity = 0.84) for the left coronary artery and 0.94 (sensitivity = 0.92, specificity = 0.96) for the right. ConclusionsA novel computed tomography–based multivariate prediction model that can be implemented routinely in real-world practice predicted coronary artery obstruction from TAVR in native aortic stenosis.

Dental topographic proxies for ecological characteristics in carnivoran mammals.

Form-function relationships in mammalian feeding systems are active topics of research in evolutionary biology. This is due principally to their fundamental importance for understanding dietary adaptations in extinct taxa and macro-evolutionary patterns of morphological transformations through changing environments. We hypothesize that three-dimensional dental topographic metrics represent stronger predictors for dietary and other ecological variables than do linear measurements. To test this hypothesis, we measured three dental topographic metrics: Relief Index (RFI), Dirichlet Normal Energy (DNE), and Orientation Patch Count Rotated (OPCR) in 57 extant carnivoran species. Premolar and molar dental topographic indices were regressed against activity, diet breadth, habitat breadth, terrestriality, and trophic level variables within a phylogenetic framework. The results of this study showed significant correlations between RFI and the ecological variables diet breadth and trophic level. Weaker correlations are documented between OPCR and activity and between DNE and trophic level. Our results suggest that cusp height is strongly reflective of dietary ecology in carnivorans as a whole, and represents a proxy mainly for different degrees of hypercarnivory observed within this group of predatory mammals.

Theoretical and experimental investigations for geometrical error during hemispherical cavity machining on CO2 laser

CO2 laser material processing has become popular due to its unique advantages such as high productivity, ease of automation, non-contact processing, greater material utilization, and minimum heat-affected zone. Polymethylmethacrylate (PMMA) is found to be one of the most suitable thermoplastics for CO2 laser machining due to its higher melting point and higher absorptivity at the CO2 laser wavelength. The scope of the present work deals with geometrical error analysis during machining of the three-dimensional spherical cavity with the help of a 2D setup of the laser. The influence of process parameters like power, cutting speed, and the number of passes of laser probe on cusp height is examined. The cusp height is measured after machining equal and unequal step size on PMMA. The experiments were performed for profile controlled approach for equal step size and accuracy approach for unequal step size. An algorithm is proposed for predicting unequal step diameter with a constant value of cusp height. It was observed that higher power, lower speed, and more number of passes of laser probe leads to minimum cusp height. Hence, the proposed algorithm for predicting unequal step diameter for a constant cusp height leads to a reduction in staircase effect, thereby, producing a smoother curve as compared to the profile controlled (equal step diameter) approach.

Tricuspidization technique with reimplantation for a bicuspid aortic valve: a case report

BackgroundBicuspid aortic valve (BAV) is the most frequent congenital cardiac anomaly. We report a successful case in which the tricuspidization technique with valve-sparing aortic root replacement was used for BAV with severe aortic regurgitation.Case presentationA 22-year-old man was admitted for progressively worsening aortic regurgitation due to a congenital BAV. Preoperative examination revealed annuloaortic ectasia and left ventricular dilatation with worsening ejection fraction. The right and left coronary cusps of the aortic valve were fused with severe prolapse. During surgery, as there was no obvious calcification or degeneration of each coronary cusp and the commissural orientation was nearly 120°, we judged that tricuspid reconstruction was preferable. Neo-left and right commissure reconstruction by raphe suspension and free margin resuspension of the non-coronary cusp were performed with valve-sparing aortic root replacement (reimplantation technique). Postoperatively, the coaptation height of each coronary cusp was remarkably increased, and aortic regurgitation and left ventricular function improved. The patient was discharged 12 days postoperatively without any complications.ConclusionsThe tricuspidization technique with valve-sparing aortic root replacement was a valuable strategy for repairing the bicuspid valve (type I) with severe aortic valve regurgitation. Although we believe that our tricuspidization technique has the potential for good durability, further experience is warranted to confirm the safety and efficacy of this technique.

Surgical Repair of a Sinus of Valsalva Aneurysm.

A surgically challenging case of an unruptured Sinus of Valsalva aneurysm (SoVA) with severe aortic regurgitation (AR) due to cusp prolapse is presented. Sinus reconstruction with a patch cut out from the sinus portion of a Gelweave Valsalva graft (Terumo Vascutek) was performed. Intraoperative measurements showed insufficient effective height of the right coronary cusp; therefore, cusp plication and pericardial patch augmentation of the right coronary cusp were performed with satisfying result.

Tomographic analysis of the anatomical proportion between buccal cusps heights and marginal ridges depths of maxillary premolars for vertical bracket positioning

ABSTRACT Objective There are several protocols for vertical positioning of brackets during bonding suggested in the literature; however, it is observed that even with a strict bonding protocol, the marginal ridges of the posterior teeth, mainly premolars, do not coincide at the end of levelling phase. The purpose of this retrospective study was to analyse whether there is an anatomical proportion between the height of the buccal cusp and the depth of the marginal ridges in the upper premolars using the point of greatest convexity on the buccal surface as a reference. Methods 40 CBCT scans were analysed using a 3D software. After the demarcation of 3 points of interest, linear measurements were recorded and compared on all upper premolars separately, through linear regression analysis. Results Although there was a tendency for a positive correlation between the recorded measurements, there was a high level of dispersion between points, and a high confidence interval between maximum and minimum values. The linear regression coefficients on teeth 14, 15, 24 and 25 were, respectively: 0.6527(0.508–0.797); 0.7426(0.521–0.964); 0.6205(0.436–0.805) e 0.7558(0.562–0.949). Conclusions The great level of variations, and the absence of an anatomical proportion makes clear the need for individualization of bracket bonding heights in upper premolars for a coincidence of marginal ridges at the end of the orthodontic levelling phase, and suggests that the use of a predetermined value on the buccal faces of premolars for brackets bonding it is not an accurate indicator of the levelling of marginal ridges.