Biomechanical Stress and Strain Analysis of Mandibular Human Region from Computed Tomography to Custom Implant Development

Currently computational tools are helping and improving the processes and testing procedures in several areas of knowledge. Computed tomography (CT) is a diagnostic tool already consolidated and now beginning to be used as a tool for something even more innovative, creating biomodels. Biomodels are anatomical physical copies of human organs and tissues that are used for diagnosis and surgical planning. The use of tomographic images in the creation of biomodels has been arousing great interest in the medical and bioengineering area. In addition to creating biomodels by computed tomography it is also possible, using this process, to create mathematical models to perform computer simulations and analyses of regions of interest. This paper discusses the creation of a biomodel of the skull-mandibular region of a patient from CT for study and evaluation of efforts in the area of the temporomandibular joint (TMJ) aiming at the design and development of a TMJ custom prosthesis. The evaluation of efforts in the TMJ region due to the forces of mastication was made using the finite element method and the results were corroborated by comparison with mandibular models studied in similar works

PRELIMINARY FINDINGS OF A POTENZIATED PIEZOSURGERGICAL DEVICE AT THE RABBIT SKULL

The number of available ultrasonic osteotomes has remarkably increased. In vitro and in vivo studies have revealed differences between conventional osteotomes, such as rotating or sawing devices, and ultrasound-supported osteotomes (Piezosurgery®) regarding the micromorphology and roughness values of osteotomized bone surfaces. Objective: the present study compares the micro-morphologies and roughness values of osteotomized bone surfaces after the application of rotating and sawing devices, Piezosurgery Medical® and Piezosurgery Medical New Generation Powerful Handpiece. Methods: Fresh, standard-sized bony samples were taken from a rabbit skull using the following osteotomes: rotating and sawing devices, Piezosurgery Medical® and a Piezosurgery Medical New Generation Powerful Handpiece. The required duration of time for each osteotomy was recorded. Micromorphologies and roughness values to characterize the bone surfaces following the different osteotomy methods were described. The prepared surfaces were examined via light microscopy, environmental surface electron microscopy (ESEM), transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM) and atomic force microscopy. The selective cutting of mineralized tissues while preserving adjacent soft tissue (dura mater and nervous tissue) was studied. Bone necrosis of the osteotomy sites and the vitality of the osteocytes near the sectional plane were investigated, as well as the proportion of apoptosis or cell degeneration. Results and Conclusions: The potential positive effects on bone healing and reossification associated with different devices were evaluated and the comparative analysis among the different devices used was performed, in order to determine the best osteotomes to be employed during cranio-facial surgery

Cone-Beam Computed Tomography Accuracy for Morphological and Morphometric Evaluation of Mandibular Condyles Using Small FOV and Small Voxel Size

  The objective of this study is to evaluate the accuracy of cone beam computed tomography (CBCT) in determining and visualizing the morphology and morphometry of the mandibular condyle. Narrative reviews with article searches were carried out through NCBI's PubMed database and Scopus from September 2021–October 2021, with the inclusion criteria articles published in 2011–2021.  The temporomandibular joint (TMJ) has a crucial role and is closely related to the masticatory system. The diagnosis of temporomandibular disorder (TMD) is not easy and is complex enough to require a comprehensive clinical and radiographic examination. Pathological changes such as erosion of the condyle, fracture, ankylosis, dislocation, and osteophyte can be well seen using CBCT imaging. CBCT images obtained with smaller field of view (FOV) have smaller a voxel size and a higher image resolution. FOV or scan volume refers to the anatomical area that will be included in the data volume or the area of the patient that will be irradiated. The dimension of FOV depends on the detector size and shape, the beam projection geometry, and the ability to collimate the beam. Voxel size is an important component of image quality, related to both the pixel size and the image matrix. Selection of small FOV and small voxel size is recommended because they provide better visualization and detail for the evaluation of morphology and morphometry of the condyle, especially the detection of erosion and defects on the condyle surface

Finite Element Analysis and Its Applications in Dentistry

Finite Element Analysis or Finite Element Method is based on the principle of dividing a structure into a finite number of small elements. It is a sophisticated engineering tool, which has been used extensively in design optimization and structural analysis first originated in the aerospace industry to study stress in complex airframe structures. This method is a way of getting a numerical solution to a specific problem, used to analyze stresses and strains in complex mechanical systems. It enables the mathematical conversion and analysis of mechanical properties of a geometric object with wide range of applications in dental and oral health science. It is useful for specifying predominantly the mechanical aspects of biomaterials and human tissues that cannot be measured in vivo. It has various advantages, can be compared with studies on real models, and the tests are repeatable, with accuracy and without ethical concerns

Osteoarthritis

Osteoarthritis is one of the most debilitating diseases affecting millions of people worldwide. However, there is no FDA approved disease modifying drug specifically for OA. Surgery remains an effective last resort to restore the function of the joints. As the aging populations increase worldwide, the number of OA patients increases dramatically in recent years and is expected to increase in many years to come. This is a book that summarizes recent advance in OA diagnosis, treatment, and surgery. It includes wide ranging topics from the cutting edge gene therapy to alternative medicine. Such multifaceted approaches are necessary to develop novel and effective therapy to cure OA in the future. In this book, different surgical methods are described to restore the function of the joints. In addition, various treatment options are presented, mainly to reduce the pain and enhance the life quality of the OA patients

Management of bone defects with Bio-oss

Introduction: The defects in the alveolar bone might appear as a result of congenital malformations, traumatic injuries, periodontal disease, surgical traumas, chronic periapical changes and tumors from benign or malignant origin. The aim of this study was to provide solid and healthy area with application of Bio-Oss in the defect. Materials and methods: Based on the clinical diagnosisestablished by previously taken history, clinical examination and radiographic images oral-surgery interventions was made. To realize the aim of this work, augmentative material was implicated in the bone defects made in the patients after removal of follicular cyst, chronic periapical lesion, and parodontopathia. During the first and seventh day of the interventions, the patients have been followed through from aspect of possible development of local and general complications after the oral-surgery intervention. After period of one, three and six mount control x-ray was made. Results: Obtained results confirmed that: volume of the socket and defect of the bone was kept, fast revascularization was achieved, bone formation and slow resorption of the augmentative material was achieved, and period of normal healing without infection was also achieved. Conclusions: The augmentative materials used for treatment of bone defects besides their basic chemical and physical characteristics referring to their solubility in the body fluids, the transformation, modulation and resorption must be completely safe or secure, i.e. not to bring any risk of infection, immunological risk, physiological intolerance or inhibition of the process of restitutio ad integrum. In our study Bio-Oss was confirmed as augmentative material who had this characteristics. Keywords: bone defect, resorption of the bone, augmentative material, Bio-Os

CT Scanning

Since its introduction in 1972, X-ray computed tomography (CT) has evolved into an essential diagnostic imaging tool for a continually increasing variety of clinical applications. The goal of this book was not simply to summarize currently available CT imaging techniques but also to provide clinical perspectives, advances in hybrid technologies, new applications other than medicine and an outlook on future developments. Major experts in this growing field contributed to this book, which is geared to radiologists, orthopedic surgeons, engineers, and clinical and basic researchers. We believe that CT scanning is an effective and essential tools in treatment planning, basic understanding of physiology, and and tackling the ever-increasing challenge of diagnosis in our society

Exogenous stimulation of meniscus cells for the purpose of tissue engineering the knee meniscus

Injuries to avascular regions of menisci do not heal and result in significant discomfort to patients. Current treatments, such as partial meniscectomy, alleviate the symptoms, but lead to premature osteoarthritis due to reduced stability and changes in knee biomechanics. An alternative treatment to overcome these problems involves functional tissue engineering. This thesis examined several exogenous factors to enhance the capability of meniscus cells (MCs) to synthesize relevant ECM markers and improve the functionality of constructs in vitro. First, the effect of passage on the phenotype of MCs in monolayer was investigated, and rapid changes were observed in collagen I, collagen II, and COMP expression. Collagen I and aggrecan protein coatings assisted in reversing expression levels of certain ECM markers; however, collagen II expression could not be reversed. Next, 3D tissue engineering studies were conducted using a cell-scaffold approach with MCs seeded on PLLA meshes. Anabolic stimuli that aided in meniscus regeneration included (1) hypoxia and bFGF, which resulted in synergistic increases in the total glycosaminoglycan content and compressive properties of constructs; (2) 10 MPa static hydrostatic pressure (HP), which resulted in increases in collagen content and the relaxation modulus of constructs; and (3) 10 MPa static HP and TGF-beta1, which resulted in additive increases in collagen content, and synergistic increases in the compressive moduli of constructs. Finally, a self-assembly, scaffoldless approach was employed for meniscus regeneration using co-cultures of MCs and articular chondrocytes (ACs). A high density of cells were seeded on non-adherent agarose molds and allowed to coalesce into a construct without a scaffold. Different co-culture ratios of MCs and ACs resulted in a spectrum of fibrocartilages that recapitulated some biochemical and biomechanical properties of the rabbit meniscus. Cell culturing conditions were optimized with the identification of a smooth 1% agarose mold that resulted in geometrically-mimetic meniscus constructs. In conclusion, this thesis quantified phenotypic changes in MCs over passage, and used scaffold-based and scaffoldless approaches to regenerate constructs with biochemical and biomechanical properties in the range of native tissue values. Successful replacement of a damaged meniscus will improve the quality of patient life and reduce the risk of osteoarthritis

Case series of breast fillers and how things may go wrong: radiology point of view

INTRODUCTION: Breast augmentation is a procedure opted by women to overcome sagging breast due to breastfeeding or aging as well as small breast size. Recent years have shown the emergence of a variety of injectable materials on market as breast fillers. These injectable breast fillers have swiftly gained popularity among women, considering the minimal invasiveness of the procedure, nullifying the need for terrifying surgery. Little do they know that the procedure may pose detrimental complications, while visualization of breast parenchyma infiltrated by these fillers is also deemed substandard; posing diagnostic challenges. We present a case series of three patients with prior history of hyaluronic acid and collagen breast injections. REPORT: The first patient is a 37-year-old lady who presented to casualty with worsening shortness of breath, non-productive cough, central chest pain; associated with fever and chills for 2-weeks duration. The second patient is a 34-year-old lady who complained of cough, fever and haemoptysis; associated with shortness of breath for 1-week duration. CT in these cases revealed non thrombotic wedge-shaped peripheral air-space densities. The third patient is a 37‐year‐old female with right breast pain, swelling and redness for 2- weeks duration. Previous collagen breast injection performed 1 year ago had impeded sonographic visualization of the breast parenchyma. MRI breasts showed multiple non- enhancing round and oval shaped lesions exhibiting fat intensity. CONCLUSION: Radiologists should be familiar with the potential risks and hazards as well as limitations of imaging posed by breast fillers such that MRI is required as problem-solving tool