Development of a Visio-Haptic Integrated Dental Training Simulation System

The use of haptic devices in the medical field has become widespread in the last decade. In this study, a visio-haptic dental training system is developed using haptic and stereoscopic devices. Several advantages are offered by such a simulation system, including effective learning without any fear of making mistakes on a patient, possibility of repeating various dental operations, ease of evaluating student performance, and low-cost dental training even without an instructor. In this study, the biomechanical properties of enamel, dentin, pulp, and caries were modeled, and the parameters were fine-tuned to provide more realistic haptic sensations. Maxillary and mandibular dental arches and various dental instruments such as mouth mirror, probe, and dental drills were modeled in a 3D virtual environment. Probing and cavity preparation on teeth were implemented in the training system. Various graphical rendering methods (Surface Rendering in CPU, Iso-Surface Rendering, and Ray-Casting in GPU) were implemented and compared in performance. The implementation details and the software structure used are described. Finally, detailed performance tests by a group of dentists are conducted, and the results of these tests are presented. The performance tests found that dentists have a strong motivation to use the system and that in the aspects of usability, clarity, effectiveness, help/support provided, and satisfaction, the users' responses were above average

Syndrome of inappropriate antidiuretic hormone secretion related to Guillain-Barré syndrome after laparoscopic cholecystectomy

Background and objectives: Guillain-Barré Syndrome is one of the most common causes of acute polyneuropathy in adults. Recently, the occurrence of Guillain-Barré Syndrome after major and minor surgical operations has been increasingly debated. In Guillain-Barré syndrome, syndrome of inappropriate antidiuretic hormone secretion and dysautonomy are generally observed after maximal motor deficit. Case report: A 44-year-old male patient underwent a laparoscopic cholecystectomy for acute cholecystitis. After the development of a severe headache, nausea, diplopia, and attacks of hypertension in the early postoperative period, a computer tomography of the brain was normal. Laboratory tests revealed hyponatremia linked to syndrome of inappropriate antidiuretic hormone secretion, the patient's fluids were restricted, and furosemide and 3% NaCl treatment was initiated. On the second day postoperative, the patient developed numbness moving upward from the hands and feet, loss of strength, difficulty swallowing and respiratory distress. Guillain-Barré syndrome was suspected, and the patient was moved to intensive care. Cerebrospinal fluid examination showed 320 mg/dL protein, and acute motor-sensorial axonal neuropathy was identified by electromyelography. Guillain-Barré syndrome was diagnosed, and intravenous immune globulin treatment (0.4 g/kg/day, 5 days) was initiated. After 10 days in the intensive care unit, at which the respiratory, hemodynamic, neurologic and laboratory results returned to normal, the patient was transferred to the neurology service. Conclusions: Our case report indicates that although syndrome of inappropriate antidiuretic hormone secretion and autonomic dysfunction are rarely the initial characteristics of Guillain-Barré syndrome, the possibility of postoperative syndrome of inappropriate antidiuretic hormone secretion should be kept in mind. The presence of secondary hyponatremia in this type of clinical presentation may delay diagnosis

Periodontal ligament cell behavior on different titanium surfaces

Aim. The purpose of this study was to investigate proliferation, morphology, mineralization and mRNA expressions of mineralized tissue associated proteins of PDL cells on smooth (S), sandblasted small-grit (SSG), sandblasted large-grit (SLG) and sodium titanate (NaTi) coated titanium alloys, in vitro. Methods and materials: PDL cells were cultured with DMEM media containing 10% FBS on the S, SSG, SLG and NaTi titanium surfaces. PDL cell proliferation, mineralization and immunohistochemistry experiments for Bone Sialoprotein (BSP) were performed. The morphology of the PDL cells was examined using confocal and scanning electron microscopy (SEM). Gene expression profiles of cells were evaluated using a quantitative-polymerase chain reaction (Q-PCR) for type I collagen (COL I), Osteocalcin (OCN), osteopontin (OPN) and Runt-related transcription factor-2 (Runx2) on days 7 and 14. Results. Proliferation results on days 6 and 10 were similar in groups, while those of day 13 revealed a decrease in the NaTi group when compared to the S group. NaTi surface induced BSP mRNA expression which was correlated with mineralization tests and BSP immunostaining results. Increased Runx2 mRNA expression was also noted in the NaTi surface when compared to other surfaces. Conclusions. This study considers the NaTi surface as a potential alternative to SSG and SLG surfaces. This surface might provide a promising environment for PDL ligament-anchored implants