In order to improve the effect and efficiency of the reconstructed image after hybrid volume rendering of different kinds of volume data from medical sequential slices or polygonal models, we propose a hybrid volume rendering method based on Shear-Warp with economical hardware. First, the hybrid volume data are pre-processed by Z-Buffer method and RLE (Run-Length Encoded) data structure. Then, during the process of compositing intermediate image, a resampling method based on the dual-interpolation and the intermediate slice interpolation methods is used to improve the efficiency and the effect. Finally, the reconstructed image is rendered by the texture-mapping technology of OpenGL. Experiments demonstrate the good performance of the proposed method.
Algorithms ; Computer Graphics ; Image Processing, Computer-Assisted ; methods ; Medical Illustration ; Models, Anatomic ; Phantoms, Imaging

OBJECTIVE: To investigate whether the accuracy of 3D laser scanning is influenced by the angles and number of scans. METHODS: Using a 3D laser scanner, 10 manikins with facial markers were scanned at 7 horizontal angles (front view and at 20degrees, 45degrees, and 60degrees angles on the right and left sides). Three-dimensional facial images were reconstructed by 6 methods differing in the number and angles of scans, and measurements of these images were compared to the physical measurements from the manikins. RESULTS: The laser scan images were magnified by 0.14 - 0.26%. For images reconstructed by merging 2 scans, excluding the front view; and by merging 3 scans, including the front view and scans obtained at 20degrees on both sides; several measurements were significantly different than the physical measurements. However, for images reconstructed by merging 3 scans, including the front view; and 5 scans, including the front view and scans obtained at 20degrees and 60degrees on both sides; only 1 measurement was significantly different. CONCLUSIONS: These results suggest that the number and angle of scans influence the accuracy of 3D laser scanning. A minimum of 3 scans, including the front view and scans obtained at more than 45degrees on both sides, should be integrated to obtain accurate 3D facial images.
Manikins

No abstract available.
Audiovisual Aids*

PURPOSE: Cardiopulmonary resuscitation (CPR) education for school is extremely important in the community. In Korea, the curriculum for health care training including CPR has been established by law since 2009. The aim of this survey was to investigate the current status of CPR training in school from the viewpoint of program administration and their aids. METHODS: In January 2012, we conducted an interview survey with 243 health teachers regarding their educational status and confidence, current education condition for school, teaching materials, and opinion on governmental health policy. The characteristics of survey respondents were compared according to elementary, middle, and high school. According to their place of work, we focused on teaching methods and programs for implementation of adequate CPR practices. RESULTS: Half of the participants worked in elementary schools, 29% in middle schools, and 20% in high schools. Ninety-four percent of elementary respondents reported having ever run a CPR curriculum, and 51% of middle school respondents and 41% of high school respondents administered CPR education in 2011. The median time for CPR lessons was two class hours [interquartile range (IQR): 1~2]. The median number of students per lesson was 30 (IQR: 26~71). Among those who had been trained, 84% of the elementary school, 56% of middle school, and 55% of the high school had performed manikin practice. Healthcare textbooks (58%), group-used manikins (31%), visual aids (24%), and only 6% of individual practice manikins were secured for use as CPR teaching aids. CONCLUSION: Wide variations in CPR curriculums and educational materials were observed among different school levels, and the standard program administrations and equipment were insufficient. Therefore, strategies and guidelines for program administration should be established as soon as possible.
Audiovisual Aids ; Cardiopulmonary Resuscitation ; Curriculum ; Surveys and Questionnaires ; Delivery of Health Care ; Educational Status ; Health Policy ; Humans ; Hypogonadism ; Jurisprudence ; Korea ; Manikins ; Mitochondrial Diseases ; Ophthalmoplegia ; Teaching ; Teaching Materials

INTRODUCTIONThe aim of the study is to investigate the effect of using Automated External Defibrillator (AED) audiovisual feedback on the quality of cardiopulmonary resuscitation (CPR) in a manikin training setting.

MATERIALS AND METHODSFive cycles of 30 chest compressions were performed on a manikin without CPR prompts. After an interval of at least 5 minutes, the participants performed another 5 cycles with the use of real time audiovisual feedback via the ZOLL E-Series defibrillator. Performance data were obtained and analysed.

RESULTSA total of 209 dialysis centre staff participated in the study. Using a feedback system resulted in a statistically significant improvement from 39.57% to 46.94% (P=0.009) of the participants being within the target compression depth of 4 cm to 5 cm and a reduction in those below target from 16.45% to 11.05% (P=0.004). The use of feedback also produced a significant improvement in achieving the target for rate of chest compression (90 to 110 compressions per minute) from 41.27% to 53.49%; (P<0.001). The mean depth of chest compressions was 4.85 cm (SD=0.79) without audiovisual feedback and 4.91 (SD=0.69) with feedback. For rate of chest compressions, it was 104.89 (SD=13.74) vs 101.65 (SD=10.21) respectively. The mean depth of chest compression was less in males than in females (4.61 cm vs 4.93 cm, P=0.011), and this trend was reversed with the use of feedback.

CONCLUSIONIn conclusion, the use of feedback devices helps to improve the quality of CPR during training. However more studies involving cardiac arrest patients requiring CPR need to be done to determine if these devices improve survival.

Adult ; Audiovisual Aids ; Cardiopulmonary Resuscitation ; instrumentation ; methods ; Defibrillators ; Feedback ; Female ; Humans ; Male ; Manikins ; Middle Aged ; Pressure ; Prospective Studies ; Thorax ; Young Adult

OBJECTIVETo analyze stress distribution in alveolar bone around implants of implant supported overdentures (ISO) with linear occlusion and with anatomic occlusion at lateral mandibular position, and to justify the possibility of decreased injurious force around implants in ISO with linear occlusion.

METHODSComputerized tomography scan and finite element analysis (FEA) were used to set up two 3-D FEA models of maxillae and mandible with severe residual ridge resorption. The mucosa, linear and anatomic occlusal ISO with bar attachments, and two implants inserted between mandibular foramina were also established in the models. With the condition of imitating the loading of masseter muscles, these models were loaded to simulate the stress distributions in alveolar bone around implants under ISO at lateral occlusion position.

RESULTSAt lateral occlusion, the stress distributions in alveolar bone around implants under ISO with anatomic occlusion were mainly on the lingual and distal sides of the working side implants. However, stress distributions under ISO with linear occlusion were on the distal sides of bilateral implants. Both the stress peaks of ISOs with linear occlusion and with the anatomic one appeared in the working side. In anatomic occlusion model, sigma(z): -6.47 MPa and 6.81 MPa, sigma(1): -4.20 MPa and 7.20 MPa (negative value: compressive stress, positive value: tensile stress); in linear occlusion model, sigma(z): -4.86 MPa and 3.04 MPa, sigma(1): -3.48 MPa and 5.33 MPa.

CONCLUSIONSAt lateral occlusion, when comparing the ISO with two different occlusion schemes, stress peak in alveolar bone around implants in the linear occlusion model was lower than that in the anatomic occlusion model at equal loading situation. Stress in the alveolar bone under ISO with linear occlusion distributed more evenly than that under ISO with anatomic occlusion.

Dental Implantation ; Dental Occlusion ; Denture, Complete, Lower ; Finite Element Analysis ; Humans ; Mandible ; physiology ; Models, Anatomic ; Models, Biological ; Stress, Mechanical

PURPOSE: The aim of this study was to determine the influence of anatomical conditions on primary stability in the models simulating posterior maxilla. METHODS: Polyurethane blocks were designed to simulate monocortical (M) and bicortical (B) conditions. Each condition had four subgroups measuring 3 mm (M3, B3), 5 mm (M5, B5), 8 mm (M8, B8), and 12 mm (M12, B12) in residual bone height (RBH). After implant placement, the implant stability quotient (ISQ), Periotest value (PTV), insertion torque (IT), and reverse torque (RT) were measured. Two-factor ANOVA (two cortical conditions×four RBHs) and additional analyses for simple main effects were performed. RESULTS: A significant interaction between cortical condition and RBH was demonstrated for all methods measuring stability with two-factor ANOVA. In the analyses for simple main effects, ISQ and PTV were statistically higher in the bicortical groups than the corresponding monocortical groups, respectively. In the monocortical group, ISQ and PTV showed a statistically significant rise with increasing RBH. Measurements of IT and RT showed a similar tendency, measuring highest in the M3 group, followed by the M8, the M5, and the M12 groups. In the bicortical group, all variables showed a similar tendency, with different degrees of rise and decline. The B8 group showed the highest values, followed by the B12, the B5, and the B3 groups. The highest coefficient was demonstrated between ISQ and PTV. CONCLUSIONS: Primary stability was enhanced by the presence of bicortex and increased RBH, which may be better demonstrated by ISQ and PTV than by IT and RT.
Dental Implants ; In Vitro Techniques* ; Maxilla* ; Maxillary Sinus ; Models, Anatomic ; Polyurethanes ; Torque

PURPOSE: Sufficient area in the interforaminal region is required for dental implant placement, and the anterior loop of the mandibular canal is located within the limits of this area. The aim of this study was to evaluate the prevalence and extent of the anterior loop in a Brazilian sample population using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: CBCT images from 250 patients (500 hemimandibles) obtained for various clinical indications were randomly selected and evaluated to determine the presence and length of the anterior loop. The length of the anterior loop was then compared based on gender, age, and the side of the mandible. The data were analyzed using the Pearson chi-square test and linear regression analysis. RESULTS: An anterior loop was identified in 41.6% of the cases, and its length ranged from 0.25 mm to 4.00 mm (mean, 1.1±0.8 mm). The loop had a greater mean length and was significantly more prevalent in males (p=0.014). No significant differences were found between the right and left sides regarding length (p=0.696) or prevalence (p=0.650). CONCLUSION: In this study, a high prevalence of the anterior loop of the mandibular canal was found, and although its length varied greatly, in most cases it was less than 1 mm long. Although this is a prevalent anatomical variation, safety limits for the placement of implants in this region cannot be established before an accurate evaluation using imaging techniques in order to identify and preserve the neurovascular bundles.
Anatomic Variation ; Cone-Beam Computed Tomography* ; Dental Implants ; Humans ; Linear Models ; Male ; Mandible ; Prevalence

PURPOSE: This study aimed to evaluate the effects of i) the extent of peri-implant bone defects and ii) the application of bone cement on implant stability with respect to the measurement direction. METHODS: In 10 bovine rib bones, 4 implant osteotomies with peri-implant bone defects of various widths were prepared: i) no defect (D0), ii) a 2-mm-wide defect (D2), iii) a 4-mm-wide defect (D4), and iv) a 8-mm-wide defect (D8). The height of all defects was 10 mm. Implant stability quotient (ISQ) values and Periotest values (PTVs) were measured after implant placement and bone cement application. RESULTS: With increasing defect width, decreased ISQs and increased PTVs were observed. Statistically significant differences were found between groups D0 and D8, D0 and D4, and D2 and D8. Prior to bone cement application, inconsistent PTVs were found in group D8 depending on the measurement direction. Bone cement increased the implant stability. CONCLUSION: Peri-implant bone deficits measuring around 50% of the implant surface compromised implant stability. Clinically, PTVs should be cautiously interpreted in implants with large peri-implant defects due to inconsistent recordings with respect to the measurement direction.
Alveolar Bone Loss ; Bone Transplantation ; Dental Implants ; In Vitro Techniques ; Models, Anatomic ; Osteotomy ; Ribs

OBJECTIVETo look for the way of three-dimensional simulation of the craniofacial system.

METHODSA three-dimensional laser scanner was used for gypsum models digitization and computed tomography scans was employed for skull reconstruction, then the data of teeth and temporomandibular joint were picked up and integrated. The ARCUS sigma system was used to record spatial mandibular movements. The data of both digital reconstruction and spatial movements were transferred into one coordinate system. The software for three-dimensional simulation was programmed.

RESULTSThe preliminary program could be used to analyze static and dynamic occlusion and gnathic relations, to check the contact points and to show from various visual angles and slices. The occlusal plane, curves, and helical axis were initially defined and displayed.

CONCLUSIONSUsing available instruments and methods, we developed the primary edition for three-dimensional simulation of the craniofacial system. However, it is far from a mature system and there is still plenty of work to be done.

Dental Occlusion ; Humans ; Imaging, Three-Dimensional ; Mandible ; physiology ; Models, Anatomic ; Skull ; Temporomandibular Joint ; physiology ; Tooth