Methods for medical applications

The book describes the significant multidisciplinary research findings at the Università Politecnica delle Marche and the expected future advances. It addresses some of the most dramatic challenges posed by today's fast-growing, global society and the changes it has caused. It also discusses solutions to improve the wellbeing of human beings. The book covers the main research achievements in the different disciplines of the physical sciences and engineering, as well as several research lines developed at the university's Faculty of Engineering in the fields of electronic and information engineering, telecommunications, biomedical engineering, mechanical engineering, manufacturing technologies, energy, advanced materials, chemistry, physics of matter, mathematical sciences, geotechnical engineering, circular economy, urban planning, construction engineering, infrastructures and environment protection, technologies and digitization of the built environment and cultural heritage. It highlights the international relevance and multidisciplinarity of research at the university as well as the planned research lines for the next years.

Keywords: Higher education , History of UNIVPM , University development , University governance , UNIVPM

Background: The combination of breast conserving surgery (BCS) with plastic surgery techniques has provided a useful surgical tool matching the radicality of the oncological excision with the preservation of breast cosmesis. Even though BCS represents a good option for surgical treatment of tumors located in these quadrants, wide excisions often necessitate breast reshaping in order to avoid nipple areola complex (NAC) displacement and skin retraction. We present a new surgical technique to repair upper-outer quadrants' defects following breast cancer excision using dermo-glandular flaps and an axillary adipo-fascial flap. Methods: During the period from January 2014 to December 2015, 168 patients with an upper-outer quadrant's breast cancer have been treated in our Department. 83 women have been treated with the described oncoplastic technique and immediate contra-lateral symmetrisation and 85 women underwent standard BCS. We present surgical, oncological and cosmetic outcomes comparing our results with standard BCS. Results: At a mean follow-up of 27 months loco-regional recurrences in the two groups were comparable. Short-term complication rates were comparable between the two groups. Re-intervention rates for positive margins were significantly higher in the standard BCS group. The overall satisfaction with cosmetic outcome both assessed by the patient and the surgeon was significantly higher in the oncoplastic group. Conclusions: The proposed oncoplastic technique represents a safe and effective solution for reshaping that follows upper-outer breast cancer wide excision, achieving comparable complication rates, lower re-intervention rates for positive margins and better cosmetic results when compared with standard BCS.

Keywords: Breast Cancer , Oncoplastic breast surgery , Surgical technique

Recently, robotics has increasingly become a companion for the human being and assisting physically impaired people with robotic devices is showing encouraging signs regarding the application of this largely investigated technology to the clinical field. As of today, however, exoskeleton design can still be considered a hurdle task and, even in modern robotics, aiding those patients who have lost or injured their limbs is surely one of the most challenging goal. In this framework, the research activity carried out by the Department of Industrial Engineering of the University of Florence concentrated on the development of portable, wearable and highly customizable hand exoskeletons to aid patients suffering from hand disabilities, and on the definition of patient-centered design strategies to tailor-made devices specifically developed on the different users' needs. Three hand exoskeletons versions will be presented in this paper proving the major taken steps in mechanical designing and controlling a compact and lightweight solution. The performance of the resulting systems has been tested in a real-use scenario. The obtained results have been satisfying, indicating that the derived solutions may constitute a valid alternative to existing hand exoskeletons so far studied in the rehabilitation and assistance fields.

Keywords: Biomechanical engineering , Hand exoskeleton , Kinematic analysis , Mechanism design and optimization , Mechatronics , Wearable robotics

This study proposes a novel occlusions detection and restoration strategy. The aim is to success with 3D face recognition even when faces are partially occluded by external objects. The method, which relies on geometrical facial properties, is designed for managing two types of facial occlusions (eye and mouth occlusions due to hands). First occlusions are detected and (if present) classified, by considering their effects on the 3D points cloud. Then, the occluded regions are progressively removed, and finally, the non-occluded symmetrical regions are used to restore the missing information. After the restoration process, face recognition is performed relying on the restored facial information and on the localized landmarks. The landmarking methodology relies on derivatives and on 12 differential geometry descriptors. The discriminating features adopted for facial comparison include shape index histograms, Euclidean and geodetical distances between landmarks, facial curves, and nose volume. Obtained recognition rates, evaluated on the whole Bosphorus database and on our private dataset, ranging from 92.55 to 97.20% depending on the completeness of data.

Keywords: 3D face , Differential geometry , Face analysis , Face recognition , Feature extraction

Three-dimensional technologies have had a wide diffusion in several fields of application throughout the last decades; medicine is no exception and the interest in their introduction in clinical applications has grown with the refinement of such technologies. We focus on the application of 3D methodologies in maxillofacial surgery, where they can give concrete support in surgical planning and in the prediction of involuntary facial soft-tissue changes after planned bony repositioning. The purpose of this literature review is to offer a panorama of the existing prediction methods and software with a comparison of their reliability and to propose a series of still pending issues. Various software are available for surgical planning and for the prediction of tissue displacements, but their reliability is still an unknown variable in respect of the accuracy needed by surgeons. Maxilim, Dolphin and other common planning software provide a realistic result, but with some inaccuracies in specific areas of the face; it also is not totally clear how the prediction is obtained by the software and what is the theoretical model they are based on.

Keywords: 3D face analysis , Orthognathic surgery , Prediction methods , Soft tissue prediction , Surgical planning

In recent years, facial expression analysis and recognition (FER) have emerged as an active research topic with applications in several different areas, including the human-computer interaction domain. Solutions based on 2D models are not entirely satisfactory for real-world applications, as they present some problems of pose variations and illumination related to the nature of the data. Thanks to technological development, 3D facial data, both still images and video sequences, have become increasingly used to improve the accuracy of FER systems. Despite the advance in 3D algorithms, these solutions still have some drawbacks that make pure three-dimensional techniques convenient only for a set of specific applications; a viable solution to overcome such limitations is adopting a multimodal 2D+3D analysis. In this paper, we analyze the limits and strengths of traditional and deep-learning FER techniques, intending to provide the research community an overview of the results obtained looking to the next future. Furthermore, we describe in detail the most used databases to address the problem of facial expressions and emotions, highlighting the results obtained by the various authors. The different techniques used are compared, and some conclusions are drawn concerning the best recognition rates achieved.

Keywords: 2D/3Dcomparison , 3Dface analysis , Action units , Deep learning-based FER , Facial action coding system , Facial expression recognition

Nowadays, facial mimicry studies have acquired a great importance in the clinical domain and 3D motion capture systems are becoming valid tools for analysing facial muscles movements, thanks to the remarkable developments achieved in the 1990s. However, the face analysis domain suffers from a lack of valid motion capture protocol, due to the complexity of the human face. Indeed, a framework for defining the optimal marker set layout does not exist yet and, up to date, researchers still use their traditional facial point sets with manually allocated markers. Therefore, the study proposes an automatic approach to compute a minimum optimized marker layout to be exploited in facial motion capture, able to simplify the marker allocation without decreasing the significance level. Specifically, the algorithm identifies the optimal facial marker layouts selecting the subsets of linear distances among markers that allow to automatically recognizing with the highest performances, through a k-nearest neighbours classification technique, the acted facial movements. The marker layouts are extracted from them. Various validation and testing phases have demonstrated the accuracy, robustness and usefulness of the custom approach.

Keywords: 3D face , Face analysis , Feature extraction , Marker optimization , Motion capture

As the potentials of technology grow, the embedding of IT advances in different fields and applications increases. A recent example is virtual reality and in particular the virtual product. The possibility of having a product in a virtual form allows creators and designers to efficiently manage the cycle of a product generation and evolution. The key advantage of the “virtual” is to have the product in advance, even in the conceptualization phase, with clear benefits in terms of consumptions of resources and, hence, sustainability. A potential customer could thus interact with a product-to-be and provide feedback about its look and feel, its usability, and, most of all, give an emotional response. In this context, the interaction between the virtual product and the future customer becomes a core point for the new approaches related to user-centred and user experience design, giving birth to a design methodology called “emotional design”. In particular, the study of facial expressions seems to be the more reliable and attractive aspect of it.

Keywords: 3D , Concept design , Emotional design , Facial expression recognition , PLM , Virtual reality

Surgical interventions for jaw reconstruction require the design and the production of surgical guides that allow the surgeon to operate quickly and accurately. In some cases, the reconstruction is performed by inserting a prothesis, thus operating exclusively on the jaw, while in other cases the reconstruction is performed by withdrawing and inserting part of the fibula in place of the original jaw bone. This project aims to develop a procedure that allows 3D modeling of the surgical guides necessary for surgical intervention. The idea is to find a surgical guide archetype, a starting shape for the surgeon so that the cutting planes can be oriented without the surgical guide having to be redesigned from scratch for every single patient. The first step of the procedure is the segmentation, performed applying the thresholding operation on the images provided by magnetic resonance MR in order to identify the region of interest (ROI). The second step is the reconstruction of the 3D model, so that a mesh is obtained from 2D images. Subsequently the mesh is post-processed and the cutting plans along which the surgeon will intervene are defined.

Keywords: 3D modeling , 3D reconstruction , Maxillofacial surgery , Surgical guides

This work proposes a method for recognizing the main 13 Facial Action Units and the 6 basic emotions. The methodologies rely on Differential Geometry to extract relevant discriminant features from the query faces, and on some linear quantities used as measures: Euclidean, geodesic, and angles between 17 automatically extracted soft-tissue landmarks. A thresholding system which evaluates local properties of connected regions, selected through tailored geometrical descriptors, supports the identification of the AUs. Then, a technique based on crisp logic allows the identification of the global expression. The three-dimensional context has been preferred due to its invariance to different lightening/make-up/camouflage conditions.

Keywords: Emotional design , Face expression recognition , Intelligent drive

This paper proposes a methodology to assess the discriminative capabilities of geometrical descriptors referring to the public Bosphorus 3D facial database as testing dataset. The investigated descriptors include histogram versions of Shape Index and Curvedness, Euclidean and geodesic distances between facial soft-tissue landmarks. The discriminability of these features is evaluated through the analysis of single block of features and their meanings with different techniques. Multilayer perceptron neural network methodology is adopted to evaluate the relevance of the features, examined in different test combinations. Principle component analysis (PCA) is applied for dimensionality reduction.

Keywords: 3D face recognition , Dimensionality reduction , Geometrical descriptors , Neural network , Principal component analysis

This paper proposes a methodology to assess the discriminative capabilities of geometrical descriptors referring to the public Bosphorus 3D facial database as testing dataset. The investigated descriptors include histogram versions of Shape Index and Curvedness, Euclidean and geodesic distances between facial soft-tissue landmarks. The discriminability of these features is evaluated through the analysis of single block of features and their meanings with different techniques. Multilayer perceptron neural network methodology is adopted to evaluate the relevance of the features, examined in different test combinations. Principle Component Analysis (PCA) is applied for dimensionality reduction.

Keywords: 3D face recognition , Dimensionality reduction , Geometrical descriptors , Neural network , Principal component analysis

Purpose: To determine the trueness and precision of frameworks manufactured with a selective laser melting/milling hybrid technique (SLM/m) and conventional milling by comparing the implant-platform/framework interface with those of the original computer-aided design (CAD). Materials and Methods: Using a virtual 6-implant-supported full-arch framework CAD drawing, 27 titanium replicas were manufactured by 3 independent manufacturing centers (n = 9/center) using a hybrid SLM/m technology (labs 1 and 2) or the conventional milling technique (lab 3). Using an opto-mechanical coordinate measuring machine, the frameworks' misfit distribution and patterns were analyzed, and the position error between paired platform positions within each framework was evaluated to calculate the misfit tendency for each group. A multilevel analysis using a mixed-effects model was conducted (α = 0.05). The trueness was evaluated as the dimensional difference from the original, while the precision as the dimensional difference from a repeated scan. Results: The 3 dimensional misfits differed significantly among the 3 groups, with the milled group exhibiting the least accurate outcome (p = 0.005). The mean 3D positioning errors ranged from 8 to 16 µm and from 9 to 22 µm for the SLM/m technique (labs 1 and 2, respectively), and from 20 to 35 µm for conventional milling (lab 3). Regarding the misfit distribution pattern, the misfit increased with the distance between paired platform positions in all groups. Conclusions: All groups had 3D misfits well within the error limits reported in the literature. The 3D misfits of new hybrid (SLM/milling) and conventional (milling) procedures differed significantly among them, with the milling technique the less accurate and precise. The largest errors in all groups were found between the most distant implants, resulting in a correlation between the framework span and the inaccuracies.

Keywords: CAD/CAM , implant prosthesis , opto-mechanical measurement , oral rehabilitation , precision , trueness

The pre-operative planning of a hip arthroplasty entails the choice of the prosthetic hip model and of the position of both joint components with reference to bone. Assessing the impact of geometrical factors on the final hip range of motion (ROM) is not trivial, since it requires performing 3D evaluations. Nonetheless, it deserves to be studied since hip impingement and dislocation are still relevant complications in hip arthroplasty.This work pertains a numerical model for the assessment of the hip ROM in relation to cotyle position. External/internal rotation is considered as a benchmark, and multiple combinations of acetabular anteversion/inclination are considered.According to results, over two hundred different geometric configurations can be examined in few minutes, and the cotyle position can be so optimized with relevant benefits in term of hip ROM.

When a new material for the realization of an implantable device in the bone is being studied, in addition to its chemical-physical-mechanical characterization, tests regarding osteointegration are performed. Usually, researchers evaluate the ability of biomaterials to bind to the bone under load-bearing conditions, through animal experiments in the phase of a preclinical study, provided the respective authorization by the ethics committee. In more detail, plugs made of the material under investigation are prepared and implanted into a weight-bearing portion of the skeleton of animals (typically into the knee joint of goats, pigs, rabbits or dogs); after a pre-set time, the animal is sacrificed, the bone element is extracted, it is tested mechanically – generally by means of a pull-out test – and finally it is examined histologically. Mechanical tests often require demanding specimen preparation, which could bias results. In the scope of a research regarding the interface behaviour of a ceramic plug (two different ceramic plugs) compared to a titanium one, the authors have suggested a novel testing technique which allows to perform ‘push-in' tests, instead of the more common pull-out tests. This methodology has been followed here to compare titanium versus ceramic plugs at different times from implant (0, 3 months, 1 year) into goat knees. As a result, the study reports the shear resistance of bone–plug interfaces. The statistical analysis of the data allowed us to establish that titanium plugs systematically exhibit a higher resistance (p<0.10); this resistance undergoes a significant increment as time passes (p<0.07) due to progressive osteointegration.

Keywords: Biomaterial interface , Bone , Mechanical test , Osteointegration

Objectives: To investigate the in vitro cytotoxicity of different thermoplastic materials for clear aligners on human primary gingival fibroblasts (HGFs). Materials and Methods: Four materials for clear aligners were considered in this study: Duran (Scheu-Dental GmbH, Iserlohn, Germany), Biolon (Dreve Dentamid GmbH, Unna, Germany), Zendura (Bay Materials LLC, Fremont, CA, USA), and SmartTrack (Align Technology, San Jose, CA, USA). Three out of four materials (Duran, Biolon, Zendura) were assessed as thermoformed and nonthermoformed, whereas the SmartTrack was assessed only as thermoformed. The samples were placed at 378C in airtight test tubes containing Dulbecco's Modified Eagle's Medium (DMEM; 0.1 mg/mL) for 14 days. The cell viability of HGFs cultured with this medium was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Data were analyzed by means of one-way and two-way analysis of variance and post hoc tests (a ¼ 0.05). Results: Each material exhibited a slight cytotoxic effect after 14 days. The highest cytotoxicity level on HGFs was achieved by Biolon (64.6% 6 3.3 of cell viability), followed by Zendura (74.4% 6 2.3 of cell viability), SmartTrack (78.8% 6 6.3 of cell viability), and finally Duran (84.6% 6 4 of cell viability), which was the least cytotoxic. In the comparison between nonthermoformed and thermoformed materials for Duran, Biolon, and Zendura, the thermoformed materials showed the highest level of cytotoxicity (P, .001). Conclusions: Under the experimental conditions of this study, all the materials for clear aligners presented a slight cytotoxicity. Biolon was the most cytotoxic and the thermoforming process increased the cytotoxicity of the materials.

Keywords: Biocompatibility , Clear aligners , Cytotoxicity , Orthodontics

Robotics is increasingly involving many aspects of daily life and robotic-based assistance to physically impaired people is considered one of the most promising application of this largely investigated technology. However, the World Health Organization reports that, so far, only 10% of people in need can get access to the so-called assistive technology also due to its high costs. This work aims to tackle the aforementioned point presenting an innovative control strategy for a low-cost hand exoskeleton system based on surface electromyography signals. Most of the activities of daily living are, in fact, carried out thanks to the hands while the exploitation of surface electromyography signals represents a non-invasive technique in straightforwardly controlling wearable devices. Although such approach results deeply studied in literature, it has not been deeply tested on real patients yet. The main contribution of this article is hence not only to describe a novel control strategy but also to provide a detailed explanation of its implementation into a real device, ready to be used. Finally, the authors have evaluated and preliminary tested the proposed technique enrolling a patient in a single-case study.

Keywords: assistive devices , control strategy , hand exoskeletons , Surface EMG , wearable robotics

In recent years the science of dental materials and implantology have taken many steps forward. In particular, it has tended to optimize the implant design, the implant surface, or the connection between implant and abutment. All these features have been improved or modified to obtain a better response from the body, better biomechanics, increased bone implant contact surface, and better immunological response. The purpose of this article, carried out by a multidisciplinary team, is to evaluate and understand, through the use also of bioengineering tests, the biomechanical aspects, and those induced on the patient's tissues, by dental implants. A comparative analysis on different dental implants of the same manufacturer was carried out to evaluate biomechanical and molecular features. Von Mises analysis has given results regarding the biomechanical behavior of these implants and above all the repercussions on the patient's tissues. Knowing and understanding the biomechanical characteristics with studies of this type could help improve their characteristics in order to have more predictable oral rehabilitations

Keywords: biomechanical phenomena , bone tissue , dental implants , dental occlusion , dental prosthesis design , finite element analysis , immunological , osseointegrated implants , osseointegration , wound healing

HoloLens is the most recent and advanced forms of wearable Mixed Reality (MR) technology. It enables the user wearing a head-mounted device to experience 3D holographic objects “inside” the visualization of the real environment where he or she is located. Existing HoloLens applications have been developed in domains such as data visualization, entertainment, industrial training, education, and tourism, but the use of this technology in the arena of mental health is largely unexplored. The paper presents a HoloLens-based system called MemHolo that addresses persons with mild Alzheimer's Disease (AD). AD is associated to a chronic progressive neurodegenerative process that severely affects cognitive functioning (especially memory) and some motor functions. MemHolo is intended to be used as a cognitive training tool to practice short-term and spatial memory in a safe and controlled virtual environment, and to mitigate the effects of mental decline. The paper discusses the design process of MemHolo, and describes three evaluation studies on progressive prototypes. To our knowledge, MemHolo is the first HoloLens application designed natively for persons with AD. Our empirical work sheds a light on how these people experience HoloLens applications, highlights some challenges and potential benefits of using MR technology in the AD arena, and may pave the ground towards new forms of treatment.

Keywords: Alzheimer disease (AD) , Augmented reality , Cognitive training , Elderly , HoloLens , Mixed reality

HoloLearn is a Mixed Reality (MR) application that exploits Microsoft HoloLens to help people with Cognitive Disability improve autonomy in everyday life. Using HoloLearn, the user is immersed in a MR environment based on the surrounding space, in which s/he can learn simple daily tasks in an engaging way, with the help of a virtual assistant if needed.

Keywords: Augmented Reality , Cognitive Disability , Holograms , HoloLens , Mixed Reality , Virtual Assistant