Planning Of Implants Research Articles

The diagnostic accuracy of aortic valve calcium score in patients with low gradient and high gradient aortic stenosis

Abstract Introduction The standard imaging modality for diagnosing aortic stenosis (AS) is echocardiography (echo), by which the definition of severe AS is based on the transvalvular mean gradient (AMG) (>40 mmHg) and aortic valve area (AVA) (<1 cm2). However, in around one quarter of the cases, echo provides discordant findings (AVA<1 cm2, despite of an AMG <40 mmHg), complicating clinical decision making. Computed tomography aortic valve calcium scoring (CT- AVCS) offers an alternative diagnostic method. In cases with discordant echo measurements current guidelines recommend the use CT-AVCS to decide on severity. Purpose Our aim was to validate the sensitivity of the recommended AVCS thresholds within our patient population, as well as to identify any factors associated with below cut-off AVCS values despite confirmed severe AS (low AVCS). Methods Our retrospective study included 332 consecutive patients with severe AS (AVA ≤1 cm2), who underwent CT angiography (CTA) for transcatheter aortic valve implantation (TAVI) planning. Based on the AMG the patients were classified into high gradient (HG: AMG ≥ 40 mmHg) and low gradient (LG: AMG <40 mmHg) groups. In the LG group AS severity was assessed by a multiparametric algorithm. To specify the predictors of low AVCS among patients with HG-AS, logistic regression analysis was used. The patients were followed for 50 months. Cox proportional hazard model was used to assess the risk of death from any cause. Results The HG-AS group consisted of 244 and the LG-AS cohort of 88 patients. In the HG-AS population the sensitivity of AVCS to diagnose severe AS was 89%. Within the HG severe AS group, logistic regression analysis revealed an association between low AVCS and the AMG (OR 0.89, CI 0.83 – 0.95, p <0,001), whereas none of the other tested factors (age, sex, hypertension, diabetes, left ventricle function, renal function) showed any association. In the LG-AS group, contrary to the HG- AS patients, the sensitivity of AVCS to define severe LG AS was limited (53% in males and 67% in females). Over a median follow-up of 50 months, the prognosis of HG AS patients with low AVCS was more favourable than that of the high AVCS patient population (HR 0.41; CI 017 – 097; p=0.04), however, in the LG AS group, the prognosis was not different when stratifying the patients according to high or low AVCS (p=0.21). Conclusions Our results confirmed that among patients with HG AS, the recommended AVCS thresholds provide a good diagnostic sensitivity for severe AS. Nonetheless, the number of severe AS patients with low AVCS is not negligible, especially within the LG-AS population, where the diagnosis is the most challenging. Our findings underline that in patients with discordant echocardiographic findings, a personalized, multiparametric diagnostic approach is needed, instead basing the final diagnosis exclusively on AVCS.

Unleashing the potential of applied UNet architectures and transfer learning in teeth segmentation on panoramic radiographs

Accurate tooth segmentation in panoramic radiographs is a useful tool for dentists to diagnose and treat dental diseases. Segmenting and labeling individual teeth in panoramic radiographs helps dentists monitor the formation of caries, detect bone loss due to periodontal disease, and determine the location and orientation of damaged teeth. It can also aid in both the planning and placement of dental implants, as well as in forensic dentistry for the identification of individuals in criminal cases or human remains. With the advancement of artificial intelligence, many deep learning-based methods are being developed and improved. Although convolutional neural networks have been extensively used in medical image segmentation, the UNet and its advanced architectures stand out for their superior segmentation capacities. This study presents four semantic segmentation UNets (Classic UNet, Attention UNet, UNet3+, and Transformer UNet) for accurate tooth segmentation in panoramic radiographs using the new Tufts Dental dataset. Each model was performed using transfer learning from ImageNet-trained VGG19 and ResNet50 models. The models achieved the best results compared to the other literature models with dice coefficients (DC) and intersection over union (IoU) of 94.64% to 96.98% and 84.27% to 94.19%, respectively. This result suggests that Unet and its variants are more suitable for segmenting panoramic radiographs and could be useful for potential dental clinical applications.

Analysis of factors affecting bone volume changes after immediate implantation in the maxillary central incisor.

This study aimed to evaluate the clinical outcomes of immediate implantation of single maxillary central incisor and explore factors affecting post-implant bone volume. Clinical data and imaging records from pre-surgery, the day of surgery, and 6 months post-surgery of 100 patients (100 implants) with non-salvageable maxillary central incisors who underwent immediate implantation were collected. Bone thickness at the cervical, middle, and apical regions of the implant's labial and palatal sides were measured immediately post-surgery and at 6 months, and bone volume changes were observed. A regression analysis model was used to assess predictive factors for labial and palatal bone plate thickness. At 6 months post-surgery, the labial bone thicknesses at the cervical, middle, and apical regions were 2.35, 2.29, and 3.28 mm, respectively, and those of the palatal side were 0.00, 2.40, and 6.05 mm, respectively. The cervical region had the highest alveolar crest collapse rates, with 32.87% on the labial side and 62.20% on the palatal side. The regression model indicated that factors influencing the thickness of bone at the cervical labial side of the implant included initial bone thickness, the implant center to adjacent tooth center angle, implant diameter, and the type of implant closure (P<0.05). The initial bone thickness on the palatal side was the sole predictor for bone thickness on the palatal side (P<0.05). Immediate implantation of single maxillary central incisors yields effective clinical results. The thickness of new bone around the implant is influenced by multiple factors. A comprehensive consideration of these factors in the planning of immediate implantation is necessary to achieve optimal therapeutic outcomes.

Mapping cognitive activity from electrocorticography field potentials in humans performing NBack task

Objective. Advancements in data science and assistive technologies have made invasive brain-computer interfaces (iBCIs) increasingly viable for enhancing the quality of life in physically disabled individuals. Intracortical microelectrode implants are a common choice for such a communication system due to their fine temporal and spatial resolution. The small size of these implants makes the implantation plan critical for the successful exfiltration of information, particularly when targeting representations of task goals that lack robust anatomical correlates. Approach. Working memory processes including encoding, retrieval, and maintenance are observed in many areas of the brain. Using human electrocorticography (ECoG) recordings during a working memory experiment, we provide proof that it is possible to localize cognitive activity associated with the task and to identify key locations involved with executive memory functions. Results. From the analysis, we could propose an optimal iBCI implant location with the desired features. The general approach is not limited to working memory but could also be used to map other goal-encoding factors such as movement intentions, decision-making, and visual-spatial attention. Significance. Deciphering the intended action of a BCI user is a complex challenge that involves the extraction and integration of cognitive factors such as movement planning, working memory, visual-spatial attention, and the decision state. Examining field potentials from ECoG electrodes while participants engaged in tailored cognitive tasks can pinpoint location with valuable information related to anticipated actions. This manuscript demonstrates the feasibility of identifying electrodes involved in cognitive activity related to working memory during user engagement in the NBack task. Devoting time in meticulous preparation to identify the optimal brain regions for BCI implant locations will increase the likelihood of rich signal outcomes, thereby improving the overall BCI user experience.

AGR – 2 The Multi-Dimensional Role of Neuropsychology in Diagnostically Complex Epilepsy Patients: Refining the Surgical Plan and Post-Operative Expectations

Abstract Objective We present a case highlighting the importance of neuropsychological involvement at all phases of a pre-surgical epilepsy work-up, including clinical interview, neuropsychological evaluation, Wada testing, extra-operative electrical stimulation mapping (ESM), and psychoeducation. Method A 24-year-old, right-handed, Caucasian female presented with non-lesional, intractable left-hemisphere localization-related epilepsy characterized by frequent experiences of déjà vu and autonomic sensations. Results Neuropsychological evaluation revealed weaknesses in processing speed and verbal memory implicating left hippocampal involvement. Wada testing suggested minimal contralateral memory support, indicating poor candidacy for resective surgery. The patient underwent prolonged sEEG monitoring to refine a plan for device implantation (i.e., responsive neurostimulation; RNS). No typical events were captured during extended study. Episodic somatosensory changes were captured, which had no electrographic correlate and were presumed to be non-epileptic. ESM evoked the patient’s classic semiology, elucidating nuanced information about her seizure onset zone and network. Barriers to extended monitoring and consistent, reliable engagement during ESM included depression, anxiety, and trauma; considerable neuropsychologist-led emotional support was required. Typical seizure semiology was elicited during stimulation of entorhinal cortices, posterior and anterior hippocampi, amygdala, cingulate and insula. RNS placement included a depth electrode targeting the medial structures (via a posterior approach) with a sub-temporal strip. Conclusions Involvement of neocortical and mesial temporal structures, coupled with a clear neuropsychiatric component, were believed to be poly-etiological factors to the patient’s presentation. Neuropsychological input at all phases of pre-surgical assessment was instrumental in systematically identifying and addressing her complex needs. Psychotherapeutic intervention was suggested to be equally as important to clinical, long-term patient outcome.

The Role and Applications of Artificial Intelligence in Dental Implant Planning: A Systematic Review.

Artificial intelligence (AI) is revolutionizing dentistry, offering new opportunities to improve the precision and efficiency of implantology. This literature review aims to evaluate the current evidence on the use of AI in implant planning assessment. The analysis was conducted through PubMed and Scopus search engines, using a combination of relevant keywords, including "artificial intelligence implantology", "AI implant planning", "AI dental implant", and "implantology artificial intelligence". Selected articles were carefully reviewed to identify studies reporting data on the effectiveness of AI in implant planning. The results of the literature review indicate a growing interest in the application of AI in implant planning, with evidence suggesting an improvement in precision and predictability compared to traditional methods. The summary of the obtained findings by the included studies represents the latest AI developments in implant planning, demonstrating its application for the automated detection of bones, the maxillary sinus, neuronal structure, and teeth. However, some disadvantages were also identified, including the need for high-quality training data and the lack of standardization in protocols. In conclusion, the use of AI in implant planning presents promising prospects for improving clinical outcomes and optimizing patient management. However, further research is needed to fully understand its potential and address the challenges associated with its implementation in clinical practice.

Learning three-dimensional aortic root assessment based on sparse annotations.

Analyzing the anatomy of the aorta and left ventricular outflow tract (LVOT) is crucial for risk assessment and planning of transcatheter aortic valve implantation (TAVI). A comprehensive analysis of the aortic root and LVOT requires the extraction of the patient-individual anatomy via segmentation. Deep learning has shown good performance on various segmentation tasks. If this is formulated as a supervised problem, large amounts of annotated data are required for training. Therefore, minimizing the annotation complexity is desirable. We propose two-dimensional (2D) cross-sectional annotation and point cloud-based surface reconstruction to train a fully automatic 3D segmentation network for the aortic root and the LVOT. Our sparse annotation scheme enables easy and fast training data generation for tubular structures such as the aortic root. From the segmentation results, we derive clinically relevant parameters for TAVI planning. The proposed 2D cross-sectional annotation results in high inter-observer agreement [Dice similarity coefficient (DSC): 0.94]. The segmentation model achieves a DSC of 0.90 and an average surface distance of 0.96mm. Our approach achieves an aortic annulus maximum diameter difference between prediction and annotation of 0.45mm (inter-observer variance: 0.25mm). The presented approach facilitates reproducible annotations. The annotations allow for training accurate segmentation models of the aortic root and LVOT. The segmentation results facilitate reproducible and quantifiable measurements for TAVI planning.

Photon-Counting Versus Dual-Source CT for Transcatheter Aortic Valve Implantation Planning

BackgroundCardiovascular CT is required for planning of transcatheter aortic valve implantation (TAVI). PurposeTo compare image quality, suitability for TAVI planning, and radiation dose of photon-counting CT (PCCT) with that of dual-source CT (DSCT). Material and MethodsRetrospective study on consecutive TAVI candidates with aortic valve stenosis who underwent contrast-enhanced aorto-ilio-femoral PCCT and/or DSCT between 01/2022–07/2023. Signal-to-noise (SNR) and contrast-to-noise ratio (CNR) were calculated by standardized ROI-analysis. Image quality and suitability for TAVI planning were assessed by four independent expert readers (two cardiac radiologists, two cardiologists) on a 5-point-scale. CT dose-index (CTDI) and dose-length-product (DLP) were used to calculate effective radiation dose (eRD). Results300 patients (136 female, median age: 81 years, IQR: 76-84) underwent 302 CT-examinations, with PCCT in 202, DSCT in 100; two patients underwent both. Although SNR and CNR were significantly lower in PCCT vs. DSCT-images (33.0±10.5 vs. 47.3±16.4 and 47.3±14.8 vs. 59.3±21.9, P<.001, respectively), visual image quality was higher in PCCT vs. DSCT (4.8 vs. 3.3, P <.001), with moderate overall inter-reader agreement among radiologists and among cardiologists (κ=0.60, respectively). Image quality was rated as “excellent” in 160/202 (79.2%) of PCCT vs. 5/100 (5%) of DSCT-cases. Readers found images suitable to depict the aortic valve hinge-points and to map the femoral access path in 99% of PCCT vs. 85% of DSCT (P<0.01), with suitability ranked significantly higher in PCCT vs. DSCT (4.8 vs. 3.3, P<.001). Mean CTDI and DLP, and thus eRD, were significantly lower for PCCT vs. DSCT (22.4 vs. 62.9; 519.4 vs. 895.5, and 8.8 ± 4.5 mSv vs. 15.3 ± 5.8 mSv; all P<.001). ConclusionPCCT improves image quality, effectively avoids non-diagnostic CT-imaging for TAVI planning, and is associated with a lower radiation dose compared with state-of-the-art DSCT. Radiologists and cardiologists found PCCT images more suitable for TAVI planning.

Accuracy of Boltless Frame-Based Stereo-Electroencephalography Electrode Implantation.

Boltless implantation of stereo-electroencephalography electrode is a useful alternative especially when anchor bolt is not available such as in country with limited resources or is less appropriate such as placement in patients with thin skull or at the occiput area, despite some drawbacks including potential dislodgement. While the accuracy of implantation using anchor bolt is well-studied, data on boltless implantation remain scarce. This study aimed to reveal the accuracy, permissible error for actual placement of electrodes within the grey matter, and delayed electrode dislodgement in boltless implantation. A total of 120 electrodes were implanted in 15 patients using a Leksell Stereotactic G Frame with each electrode fixed on the scalp using sutures. Target point error was defined as the Euclidean distance between the planned target and the electrode tip on immediate postimplantation computed tomography. Similarly, delayed dislodgement was defined as the Euclidean distance between the electrode tips on immediate postimplantation computed tomography and delayed MRI. The factors affecting accuracy were evaluated using multiple linear regression. The permissible error was defined as the largest target point error that allows the maximum number of planned gray matter electrode contacts to be actually placed within the gray matter as intended. The median (IQR) target point error was 2.6 (1.7-3.5) mm, and the permissible error was 3.2 mm. The delayed dislodgement, with a median (IQR) of 2.2 (1.4-3.3) mm, was dependent on temporal muscle penetration (P = 5.0 × 10-4), scalp thickness (P < 5.1 × 10-3), and insertion angle (P = 3.4 × 10-3). Boltless implantation of stereo-electroencephalography electrode offers an accuracy comparable to those using anchor bolt. During the planning of boltless implantation, target points should be placed within 3.2 mm from the gray-white matter junction and a possible delayed dislodgement of 2.2 mm should be considered.

Transfer accuracy of 3D printed versus CAD/CAM milled surgical guides for temporary orthodontic implants: A preclinical micro CT study

ObjectivesTemporary anchorage devices (TADs) have become an integral part of comprehensive orthodontic treatments. This study evaluated the transfer accuracy of three-dimensional (3D) printed and computer-aided design/computer-aided manufacturing (CAD/CAM) milled surgical guides for orthodontic TADs using micro-computed tomography (CT) imaging in a preclinical trial. MethodsOverall, 30 surgical guides were used to place TADs into typodonts; 3D printing and CAD/CAM milling were used to produce the guides. The virtual target positions of the TADs were compared to the real positions in terms of spatial and angular deviations using digital superimposition. Micro-CT imaging was used to detect the positions. To evaluate reliability, two investigators collected the measurements twice. Intra-rater and inter-rater correlations were tested. ResultsIn total, 60 palatal TADs were evaluated. The mean coronal deviations in the print group ranged from 0.15 ± 0.20 mm to 0.71 ± 0.22 mm, whereas in the mill group, they ranged from 0.09 ± 0.15 mm to 0.83 ± 0.23 mm. At the apical tip, the overall deviations in the print group ranged from 0.14 ± 0.56 mm to 1.27 ± 0.66 mm, whereas in the mill group, they ranged from 0.15 ± 0.57 mm to 1.09 ± 0.44 mm. The mean intra-class and inter-class correlation coefficients ranged from 0.904 to 0.987. No statistically significant differences were found between the groups. ConclusionsCAD/CAM milled guides yielded spatial and angular accuracies comparable to those of 3D printed guides with notable deviations in the vertical positioning of TADs. Clinical significanceDigital planning of orthodontic temporary implants combines clinical predictability and the safety of surrounding tissue. Therefore, the transfer accuracy of the guides is crucial. This preclinical study was the first to evaluate CAD/CAM milling for orthodontic guides and found its accuracy comparable to that of the current "gold standard".

Virtual Implant Planning and Surgical Guide for Single Implant Placement Fabricated from a Digital Diagnostic Cast, 2D Radiographic Imaging, and an Open-Source Program: A Dental Technique.

The following technique describes the virtual planning of a single implant by combining an intraoral digital scan, an open-source computer-aided design software program, bone sounding, and 2D radiographic imaging. The surgical implant guide is fabricated using additive manufacturing technologies. Further, the surgical implant guide positioned in the patient's mouth is used to radiographically verify the estimated mesiodistal implant angulation before proceeding with the surgical intervention and can be modified if necessary. When a CBCT scan is not available, this technique eases implant planning procedures and minimizes possible surgical complications.

Development and validation of a surgical planning tool for bone-conduction implants

BackgroundThe BONEBRIDGE® (Med-El GmbH) is a bone-conduction device comprising an external audio processor and an internal Bone Conduction-Floating Mass Transducer (BC-FMT) surgically anchored to the temporal bone. Due to the implant's size, its placement may be challenging in certain anatomies, necessitating thorough surgical planning. Manual planning methods are laborious, time-intensive, and prone to errors. This study aimed to develop and validate an automated algorithm for determining skull thickness, aiding in the surgical planning of the BONEBRIDGE and other devices requiring similar bone thickness estimations. Materials and methodsTwelve cadaveric temporal bones underwent clinical computed tomography (CT). A custom Python algorithm was developed to automatically segment bone from soft tissue, generate 3D models, and perform ray-tracing to estimate bone thickness. Two thickness colormaps were generated for each sample: the cortical thickness to the first air cell and the total thickness down to the dura. The algorithm was validated against expert manual measurements to achieve consensus interpretation. ResultsThe algorithm estimated bone-to-air thicknesses (mean = 4.7 mm, 95% Confidence Interval [CI] of 4.3–5.0 mm) that closely matched the expert measurements (mean = 4.7 mm, CI of 4.4–5.0 mm), with a mean absolute difference (MAD) of 0.3 mm. Similarly, the algorithm's estimations to the dura (6.0 mm, CI of 5.4–6.5 mm) were comparable to the expert markings (5.9 mm, CI of 5.4–6.5 mm), with a MAD of 0.3 mm. ConclusionsThe first automated algorithm to calculate skull thickness to both the air cells and dura in the temporal bone was developed. Colormaps were optimized to aid with the surgical planning of BONEBRIDGE implantation, however the tool can be generalized to aid in the surgical planning of any bone thickness application. The tool was published as a freely available extension to the open-source 3D Slicer software program (www.slicer.org).

Learn how to interpret and use intracranial EEG findings.

Epilepsy surgery is the therapy of choice for many patients with drug-resistant focal epilepsy. Recognizing and describing ictal and interictal patterns with intracranial electroencephalography (EEG) recordings is important in order to most efficiently leverage advantages of this technique to accurately delineate the seizure-onset zone before undergoing surgery. In this seminar in epileptology, we address learning objective "1.4.11 Recognize and describe ictal and interictal patterns with intracranial recordings" of the International League against Epilepsy curriculum for epileptologists. We will review principal considerations of the implantation planning, summarize the literature for the most relevant ictal and interictal EEG patterns within and beyond the Berger frequency spectrum, review invasive stimulation for seizure and functional mapping, discuss caveats in the interpretation of intracranial EEG findings, provide an overview on special considerations in children and in subdural grids/strips, and review available quantitative/signal analysis approaches. To be as practically oriented as possible, we will provide a mini atlas of the most frequent EEG patterns, highlight pearls for its not infrequently challenging interpretation, and conclude with two illustrative case examples. This article shall serve as a useful learning resource for trainees in clinical neurophysiology/epileptology by providing a basic understanding on the concepts of invasive intracranial EEG.

Iatrogenic bioprosthetic, self-expandable, transcatheter aortic valve replacement dysfunction after cardiac catheterization.

Bioprosthetic valve dysfunction (BVD) is typically a progressive process related to natural wear of the prosthesis. With acute presentations, possible durability issues or iatrogenic causes need to be considered. Here, we present 2 patients with acute BVD of self-expanding, transcatheter aortic valve replacement post-heart catheterization. The presentations and outcomes, in otherwise normally functioning valves antecedent to the heart catheterizations, raise the question of the increased complexity of coronary access in this valve platform, and whether that or other features provide for greater risk of such events. We believe this to be the first publication of such events and they help to highlight the importance of valve implantation planning, as well as familiarity with the potential complexity of coronary access during heart catheterization.

Impact of 3D imaging techniques and virtual patients on the accuracy of planning and surgical placement of dental implants: A systematic review.

The integration of advanced technologies, including three-dimensional (3D) imaging modalities and virtual simulations, has significantly influenced contemporary approaches to preoperative planning in implant dentistry. Through a meticulous analysis of relevant studies, this review synthesizes findings related to accuracy outcomes in implant placement facilitated by 3D imaging in virtual patients. A comprehensive literature search was conducted across relevant databases to identify relevant studies published to date. The inclusion criteria were studies utilizing 3D imaging techniques, virtual patients, and those focusing on the accuracy of dental implant planning and surgical placement. The selected studies were critically appraised for their methodological quality. After a rigorous analysis, 21 relevant articles were included out of 3021 articles. This study demonstrates the versatility and applicability of these technologies in both in vitro and in vivo settings. Integrating Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM), cone bean computed tomography (CBCT), and advanced 3D reconstruction methodologies showcases a trend toward enhanced precision in implant planning and placement. Notably, the evaluation parameters varied, encompassing distances, discrepancies, and deviations in the implant placement. The ongoing integration of systems such as dynamic navigation systems, augmented reality, and sophisticated software platforms shows a promising trajectory for the continued refinement of virtual reality applications in dental implantology, providing valuable insights for future research and clinical implementation. Moreover, using stereolithographic surgical guides, virtual planning with CBCT data, and 3D-printed templates consistently demonstrates enhanced precision in dental implant placement compared to traditional methods. The synthesis of the available evidence underscores the substantial positive impact of 3D imaging techniques and virtual patients on dental implant planning and surgical placement accuracy. Utilizing these technologies contributes to a more personalized and precise approach that enhances overall treatment outcomes. Future research directions and potential refinements to the application of these technologies in clinical practice should be discussed.

The feasibility of relaxation-enhanced angiography without contrast and triggering for preprocedural planning of transcatheter aortic valve implantation.

Cardiovascular MRI is advantageous in transcatheter aortic valve implantation (TAVI) planning. This study aimed to evaluate the feasibility of comprehensive non-contrast MRI [relaxation-enhanced angiography without contrast and triggering (REACT)] combined with a three-dimensional whole-heart MRI protocol for preprocedural planning of TAVI vs. computed tomography angiography (CTA). Thirty patients with severe aortic stenosis were prospectively enrolled. The anatomical properties of the aortic root anatomy, including the perimeter and area of the virtual aortic valve annulus and coronary heights, were determined from 3D whole-heart MRI and cardiac CTA (CCTA) images, respectively. The diameters of the aorta (thoracic and abdominal aorta) and iliofemoral arteries were measured from REACT and aortic CTA (ACTA) images, respectively. A paired t-test was used to compare these two modalities. Bland-Altman plots were used to assess cardiovascular MRI and CTA measurements. Transcatheter heart valve (THV) sizing was performed based on CCTA measurements and compared with 3D whole-heart MRI measurements. The extent of annular calcification on 3D whole-heart MRI images was evaluated by a four-point grading scale and compared with CCTA data. All 30 patients completed CTA and cardiovascular MRI examinations, with the TAVI procedure being administered in 25 patients. The mean acquisition time of the comprehensive MRI protocol was 18 ± 3.2 min. There were no significant differences between ACTA and REACT data in regard to the diameters of aortic and iliofemoral arteries, including the ascending thoracic aorta (37 ± 4.6 mm vs. 37.7 ± 5.2 mm, p = 0.085), descending thoracic aorta (24.3 ± 2.8 mm vs. 24.3 ± 2.8 mm, p = 0.832), abdominal aorta (20.9 ± 2.5 mm vs. 20.8 ± 2.5 mm, p = 0.602), bilateral common iliac arteries (right: 8.36 ± 1.44 mm vs. 8.42 ± 1.27 mm, p = 0.590; left: 8.61 ± 1.71 mm vs. 8.86 ± 1.46 mm, p = 0.050), and bilateral femoral arteries (right: 6.77 ± 1.06 mm vs. 6.87 ± 1.00 mm, p = 0.157; left: 6.75 ± 1.02 mm vs. 6.90 ± 0.80 mm, p = 0.142). Both modalities showed similar aortic valve morphology and semi-quantitative valve calcification (all, p's > 0.05). Overall agreement for implanted THV was found in all 25 (100%) patients assessed with both modalities. REACT combined with 3D whole-heart MRI enables reliable measurements of aortic root anatomy, annular calcification, and aorta and iliofemoral access in patients under evaluation for TAVI.

Computer Aided Full Arch Restoration by Means of One-Piece Implants and Stackable Guide: A Technical Note.

This technical note aims to present a recently developed computer-guided protocol characterized by titanium-reinforced stackable surgical guides during post-extractive implant placement and subsequent immediate loading. A full maxillary edentulism was rehabilitated with one-piece implants, starting from a pre-existing removable denture. 3D digital scans of the removable denture and upper and lower arches were performed. On this basis, a prototype with ideal esthetic and functional outcomes was realized and replicated into a custom-made radiological stent with markers. The superimposition of STL and DICOM files allowed virtual planning of one-piece implants in the ideal prosthetically driven position. The stackable guides, composed of a fixed base template and additional removable components, were then realized. The fixed template, initially secured with anchor pins to the bone, was no longer removed. The removable components, which were screwed to the base template, were used to perform implant surgery and immediate prosthetic loading. No surgical complications occurred, the implants achieved a minimum insertion torque of 35 Ncm, and immediate prosthetic loading was performed. The base template allowed for the maintenance of a fixed reference during the entire workflow, improving the transition between the digital project, the surgical procedure, and the prosthetic rehabilitation.

Comparative Assessment of Three Different Alveolar Ridge Dimension Measurement Methods before Implant Placement: An In Vivo Study.

The purpose of this study was to compare the three various techniques for measuring the alveolar ridge's dimensions prior to implant insertion. For this study, a total of 36 participants were chosen. To prepare a surgical stent, a study model was created from an alginate impression. A first point (reference point) was marked on the crest of the ridge in relation to the adjacent teeth. Then, one point (point 1) and another point (point 2) were marked at distances of 3 and 6 mm, respectively, from the reference point. Based on the procedure for measuring the size of the alveolar ridge, the study was divided into the following groups. Group I: Cone-beam computed tomography (CBCT) measurement method; Group II: Ridge mapping measurement method; Group III: Direct caliper measurements method. Descriptive statistics were used to estimate the mean and standard deviation (SD). The Student's unpaired t-test was utilized for the statistical analysis. The 5% level of significance was used. There was no significant difference found between CBCT with ridge mapping and direct caliper measurements. However, on comparison of ridge mapping and direct caliper measurements technique, at point 1, the ridge mapping was 3.88 ± 0.12 and the direct caliper measurement was 3.62 ± 0.08. At point 2, the ridge mapping was 6.58 ± 0.06 and the direct caliper measurement was 6.32 ± 0.04. There was a statistically significant difference found between these two measurement methods. Within the limitation, the current study came to the conclusion that when CBCT and ridge mapping measurements were individually compared with the gold standard-the surgical open method, CBCT-demonstrated to be a highly specific and sensitive method for detecting the residual alveolar ridge width in the treatment planning of dental implants. Evaluation of alveolar bone is necessary during treatment planning for dental implant placement. Using simply panoramic and/or periapical radiographs to evaluate the bone may not be sufficient because it only provides two-dimensional information regarding the implant locations. Therefore, for better implant placement, three-dimensional information of the implant site, such as CBCT and ridge mapping technique, should be assessed.

Influence of CBCT-derived panoramic curve variability in the measurements for dental implant planning.

To investigate whether the curve markings performed prior to panoramic and cross-sectional reconstructions can influence the planning of oral implants. Twenty oral radiologists landmarked the reference panoramic curves in 25 CBCT scans of the mandible. Bone height was measured on the resulting cross-sectional slices in the edentulous region of the lower first molar. The following data were recorded: (1) number of landmarks used to build each reference curve; (2) shape of the reference curve (inverted "U", inverted "V" or "horseshoe"); and (3) measurement in the first molar region. The data were assessed for variability based on the number of landmarks, the shape of the reference curve, and the measurements obtained. The number of landmarks used to guide the panoramic reconstruction varied among radiologists (p < 0.05), but most of them draw curves in inverted "U" shape (68-100%). The reproducibility of the measurements taken in the edentulous mandibular first molar region was excellent (84.7%). The number of landmarks and the shape of the curve did not have a significant influence on the reproducibility of the measurements (p > 0.05). Variations of the operator-dependent steps during the panoramic reconstructions occur but do not play a significant part changing the measurements taken for oral implant planning.

DEPLOYMENT BEHAVIOR OF STENT IN TAPERED VESSELS WITH MULTIPLE STENOSES: EFFECT OF DIFFERENT IMPLANTATION PLANNING SYSTEMS

In-stent restenosis (ISR), which is a common complication after stent intervention, affects the long-term outcome of stent intervention. Suitable implantation planning will effectively reduce the incidence of ISR. The aim of this study is to investigate the effect of different implantation planning on the mechanical behavior of stents in tapered vessels with multiple stenoses and select a better implantation planning. The finite element method (FEM) was used in this study. A different planning was designed as follows: (a) using a cylindrical balloon to deploy cylindrical stent (plan CC), (b) using the tapered balloon to deploy cylindrical stent (plan TC) and (c) using the tapered balloon to deploy tapered stent (plan TT). When the stent was expanded to the maximum diameter, the position of maximum vascular stress all appeared at distal plaque in three implantation plans. After balloon was deflated, the vascular stress in plan TC was the minimum. Using tapered balloon to deploy cylindrical stent has advantages in the tapered vessels with multiple stenoses and could reduce the probability of ISR. Moreover, this method could assess the mechanical properties of stent deployment in multiple stenoses and then select a better implantation planning.