PURPOSE: The purpose of this study is to evaluate the feasibility of phase contrast X-ray microtomography and microradiography, using a polychromatic synchrotron X-ray, for analysis of the mouse lung microstructure. MATERIALS AND METHODS: Normal mice were used for experiments. Some of the mouse lungs were prepared by the lung fixation-inflation method. The resulting sponge-like inflated lung samples were used for microtomography. The remaining mouse lungs were cut into 10 um sections and were used for microradiography and optical microscopic correlation. The experiments on mouse lung samples were performed at the 7B2 beamline of the Pohang Light Source in Korea. RESULTS: Phase contrast X-ray microtomography of inflated lung samples showed individual alveolar structure on 3-D reconstruction. Phase contrast microradiographs of thin lung samples showed microstructure of lung, such as alveoli and bronchioles, and were well correlated with optical microscopic images. CONCLUSIONS: The results indicate that the phase contrast X-ray microtomography and microradiography using polychromatic synchrotron X-ray is feasible for evaluation of microstructure of the lung.
Animals ; Lung/*cytology/*radiography ; Mice ; Microscopy/*methods ; Microscopy, Phase-Contrast ; X-Ray Microtomography/*methods

OBJECTIVES: The aims of this study were to quantify tug-back by measuring the pulling force and investigate the correlation of clinical tug-back pulling force with in vitro gutta-percha (GP) cone adaptation score using micro-computed tomography (µCT). MATERIALS AND METHODS: Twenty-eight roots from human single-rooted teeth were divided into 2 groups. In the ProTaper Next (PTN) group, root canals were prepared with PTN, and in the ProFile (PF) group, root canals were prepared using PF (n = 14). The degree of tug-back was scored after selecting taper-matched GP cones. A novel method using a spring balance was designed to quantify the tug-back by measuring the pulling force. The correlation between tug-back scores, pulling force, and percentage of the gutta-percha occupied area (pGPOA) within apical 3 mm was investigated using µCT. The data were analyzed using Pearson's correlation analysis, one-way analysis of variance (ANOVA) and Tukey's test. RESULTS: Specimens with a strong tug-back had a mean pulling force of 1.24 N (range, 0.15–1.70 N). This study showed a positive correlation between tug-back score, pulling force, and pGPOA. However, there was no significant difference in these factors between the PTN and PF groups. Regardless of the groups, pGPOA and pulling force were significantly higher in the specimens with a higher tug-back score (p < 0.05). CONCLUSIONS: The degree of subjective tug-back was a definitive determinant for master cone adaptation in the root canal. The use of the tug-back scoring system and pulling force allows the interpretation of subjective tug-back in a more objective and quantitative manner.
Dental Pulp Cavity ; Gutta-Percha ; Humans ; In Vitro Techniques ; Methods ; Root Canal Obturation ; Tooth ; X-Ray Microtomography

BACKGROUND: To evaluate the feasibility of a micro-image based finite element model to determine the efficacy of sequential treatments on the bone quality in a rat osteoporosis model. METHODS: Rat osteoporosis and treated osteoporosis models were established with the bone loss, restore and maintain concept. Thirty Sprague-Dawley rats were used in this study. A sham operation or ovariectomy was performed at 20 weeks after birth, which was followed by the respective sequential trials as follows: (1) sham-operation only, (2) ovariectomy only, (3) ovariectomized rats with parathyroid hormone maintenance, (4) ovariectomized rats treated with PTH for 5 weeks and then withdrawal, (5) ovariectomized rats treated with PTH for 5 weeks and then with 17 beta-estradiol, and (6) ovariectomized rats treated with parathyroid hormone for 5 weeks and then treated with zoledronate. The histomorphometry indices were determined using the micro-images from a micro-computed tomogram. Finite element analysis was carried out to determine the mechanical properties (Stiffness and Young's modulus) of the vertebra bodies. The differences in properties between the groups were compared using ANOVA and a Bonferroni's multiple group comparison procedure. RESULTS: The histomorphometry and mechanical properties were significantly better in groups (3) and (6) than in the groups (1) and (2) (p < 0.05). The stiffness (sigmas) and Young's modulus (E) was highest in group (3) following by group (6). CONCLUSIONS: Finite element analysis based on micro-images provides a useful tool that reflects the changes in micro-structural and mechanical properties of a rat vertebral body with the bone loss, restore and maintain concept.
Analysis of Variance ; Animals ; Female ; *Finite Element Analysis ; Osteoporosis/*pathology/*radiography ; Rats ; Rats, Sprague-Dawley ; Spine/*pathology/*radiography ; Tomography, X-Ray Computed/methods ; X-Ray Microtomography/*methods

This study aimed to utilize micro-computed tomography (micro-CT) analysis to compare new bone formation in rat calvarial defects using chitosan/fibroin-hydroxyapatite (CFB-HAP) or collagen (Bio-Gide) membranes. Fifty-four (54) rats were studied. A circular bony defect (8 mm diameter) was formed in the centre of the calvaria using a trephine bur. The CFB-HAP membrane was prepared by thermally induced phase separation. In the experimental group (n=18), the CFB-HAP membrane was used to cover the bony defect, and in the control group (n=18), a resorbable collagen membrane (Bio-Gide) was used. In the negative control group (n=18), no membrane was used. In each group, six animals were euthanized at 2, 4 and 8 weeks after surgery. The specimens were then analysed using micro-CT. There were significant differences in bone volume (BV) and bone mineral density (BMD) (P<0.05) between the negative control group and the membrane groups. However, there were no significant differences between the CFB-HAP group and the collagen group. We concluded that the CFB-HAP membrane has significant potential as a guided bone regeneration (GBR) membrane.
Animals ; Bone Regeneration ; Chitosan ; chemistry ; Collagen ; chemistry ; Fibroins ; chemistry ; Rats ; Rats, Sprague-Dawley ; Skull ; abnormalities ; X-Ray Microtomography ; methods

OBJECTIVEIn vivo Micro-PETICT imaging of mouse/rat brain has been widely used to non-invasively monitor brain and provides researchers a better understanding of therapeutic effects in models of human neurological disease. For the need of further processing, extraction of brain tissue from head is required and vital.

METHODSAn automatic multistep combination methods was proposed based on an improved level set framework, which includes (1) Use Fuzzy-C-Means method together with threshold and morphology methods to get the initial level-set surface automatically. (2) Combine gradient vector flow to enhance the gradient contrast and enforce the surface move toward to the object's surface much faster, especially obtain a significantly improvement in the regions of forehead and the joint between brain and neck. (3) introduce an automatic stop condition based on average bandwidth energy maximization to overcome the leakage problem.

RESULTS3 Micro-CT images of rat and 3 of mouse have been tested using the proposed methods and the average accuracy has increased by 33% for rat and 6.7% for mouse. The average processing duration for rat and mouse are about 8 minutes and 4 minutes, respectively.

CONCLUSIONSThe proposed methods were proved that it can be effectively used for Micro-PET/CT imaging of mouse/rat brain segmentation and have a great improvement on accuracy and convenience.

Animals ; Image Processing, Computer-Assisted ; methods ; Imaging, Three-Dimensional ; methods ; Mice ; Neuroimaging ; methods ; Pattern Recognition, Automated ; methods ; Rats ; X-Ray Microtomography ; methods

Microvessel networks were imaged by means of synchrotron radiation CT, A sliced loading and double threshold method was utilized for extracting vessels from large quantities of data (2 GB-5 GB). Preliminary analysis on the development of tumor microvessel networks was performed by statistically analyzing volume rendering and two qualitative factors, micro vessel density (MVD) and fractal dimension(FD).
Animals ; Female ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Microvessels ; diagnostic imaging ; Neoplasms ; blood supply ; diagnostic imaging ; Neovascularization, Pathologic ; diagnostic imaging ; pathology ; X-Ray Microtomography ; methods

OBJECTIVETo explore the preventive effect of Yougui drink on femoral head necrosis in rats under micro CT.

METHODSTwenty-five SD rats were divided into steroid hormone group (group A, 10 rats ), Yougui drink group (group B,10 rats) and normal group (group C,5 rats)with random number table. Endotoxin were injected into abdominal cavity of rats in group A and B for 2 days, methylprednisolone sodium succinate were injected by gluteus for twice a week continued for 6 weeks; group B were gavaged by Yougui drink (veryday for 8 weeks; group C did not do any processing. All rats were killed on the 10th weeks,m icro CT were used to scan femoral head in vitro and preventive effect of Yougui drink (n femoral head necrosis in rats.

RESULTSThere was statistical significance in BMD, BV/TV, Tb.N, Tb, Th, Thb, Sp, BS/TV and DA but no significance in SMI between group A and B. Comparison between A and C, there was significant meaning in BMD, BV/TV, Tb.N, Tb, Th, Tb, Sp, BS/TV, DA and SMI.

CONCLUSIONYougui drink on femoral head necrosis in rats under micro CT has preventive effect from BMD BV/TV, Tb.N, Tb, Th, Tb, Sp, BS/TV and DA.

Animals ; Apoptosis ; Bone Density ; Drugs, Chinese Herbal ; therapeutic use ; Femur Head Necrosis ; diagnostic imaging ; pathology ; prevention & control ; Rats ; Rats, Sprague-Dawley ; X-Ray Microtomography ; methods

OBJECTIVETo evaluate the reliability and superiority of micro-CT in marginal leakage assessment of Class V restorations.

METHODSClass V preparations with gingival margins in dentin and occlusal in enamel were made in sixteen extracted non-carious human molars and restored with dental bonding agents and composite resin. All teeth were then immersed in 50% ammonia-silver nitrate solution for 12 hours, followed by developing solution for 8 hours. Each restoration was scanned by a micro-CT and silver leakage was measured and three-dimensional image of the silver leakage alone cavity wall were reconstructed. Afterward, all restorations were sectioned and examined for leakage depth using a microscope. The silver leakage depth of each restoration obtained by micro-CT and microscope were compared for equivalency.

RESULTSThe silver leakage depths in gingival wall obtained with micro-CT (0.78 mm) and microscope (0.74 mm) showed no significant difference (P > 0.05), while the judgment of leakage depths in occlusal wall in micro-CT image (0.40 mm) was affected by adjacent enamel structure, giving less leakage depths compared to microscope (0.72 mm)(P < 0.01). The three-dimensional shapes of the microleakages displayed clearly by micro-CT alone wall of Class V restorations were multiform and some leakages showed channels on their way to spreading.

CONCLUSIONSMicro-CT can detect precisely the silver leakage in the dentin wall of a restoration and display its three-dimensional shape fully. Enamel structure affects the detection of the silver leakage next to it.

Dental Cavity Preparation ; Dental Enamel ; diagnostic imaging ; pathology ; Dental Leakage ; diagnostic imaging ; pathology ; Dental Restoration, Permanent ; methods ; Humans ; Imaging, Three-Dimensional ; Microscopy ; Molar, Third ; diagnostic imaging ; pathology ; X-Ray Microtomography ; methods

OBJECTIVE: To explore the feasibility of immediate implantation after tooth extraction in the maxillary molar socket with poor bone quality beneath the sinus. METHODS: We collected the data from the patients undergoing extraction of maxillary molars with poor bone quality between the sockets and sinuses. Sinus lifting and immediate implant following the extraction were performed simultaneously in these cases, and the primary stability of the implants, wound healing, and changes of the sinus were observed. At 6 months after the operations, the crowns were installed on the implants. The masticatory function was observed, and the growth of the alveolar bones and their changes after the operations were examined using microcomputed tomography (MCT). RESULTS: We analyzed 32 extraction cases with immediate implantation in the maxillary molar sockets with poor bone quality beneath the sinus. The average age of the patients was 59.8 years, and the length and diameter of the implant ranged from 8.5 to 10 mm and from 4.5 to 5.5 mm, respectively. The torque force of the implants varied from the minimum (in which cases the implants remained fixed after insertion with fingers) to the maximum of 30 N·cm. The postoperative recovery was uneventful in all the cases and no failed or movable implants were found. At 6 months after the operation, none of the patients showed abnormalities in the sinus, and in all the cases the crowns were successfully installed on the implants with good recovery of the masticatory functions. Follow-up of the patients for 12 to 96 months after the operation showed successful immediate implantation in all the cases. After the operation, the changes of the mean alveolar ridge heights on the buccal, palatal, mesial, and distal sides of the patients were 0.8069±0.6253 mm (=1.2904, >0.1), 0.5272± 0.3331 mm (=1.5836, >0.05), 0.5416±0.4048 mm (=1.3379, >0.05), and 0.5172±0.3874 mm (=1.3351, >0.05), respectively; the change of the alveolar ridge width was 0.5522±0.4381 mm (=1.2604, >0.1) mm. The dimension of the alveolar bone underwent no significant changes after the operation in these patients. CONCLUSIONS Immediate implantation in the maxillary extraction socket with a poor bone quality can avoid damages to the sinus and achieve good outcomes with such advantages of less trauma, full use of the innate gingiva and alveolar ridge, and well preserved morphology of the alveolar ridge as compared with delayed implantation.
Dental Implantation ; methods ; Dental Implants, Single-Tooth ; Feasibility Studies ; Humans ; Immediate Dental Implant Loading ; methods ; Maxilla ; Middle Aged ; Molar ; surgery ; Tooth Extraction ; Tooth Socket ; Treatment Outcome ; X-Ray Microtomography

This study describes the details of how to construct a three-dimensional (3D) finite element model of a maxillary first premolar tooth based on micro-CT data acquisition technique, MIMICS software and ANSYS software. The tooth was scanned by micro-CT, in which 1295 slices were obtained and then 648 slices were selected for modeling. The 3D surface mesh models of enamel and dentin were created by MIMICS (STL file). The solid mesh model was constructed by ANSYS. After the material properties and boundary conditions were set, a loading analysis was performed to demonstrate the applicableness of the resulting model. The first and third principal stresses were then evaluated. The results showed that the number of nodes and elements of the finite element model were 56 618 and 311801, respectively. The geometric form of the model was highly consistent with that of the true tooth, and the deviation between them was -0.28%. The loading analysis revealed the typical stress patterns in the contour map. The maximum compressive stress existed in the contact points and the maximum tensile stress existed in the deep fissure between the two cusps. It is concluded that by using the micro-CT and highly integrated software, construction of the 3D finite element model with high quality will not be difficult for clinical researchers.
Bicuspid ; diagnostic imaging ; physiology ; Biomechanical Phenomena ; Finite Element Analysis ; Humans ; Image Processing, Computer-Assisted ; Imaging, Three-Dimensional ; methods ; Maxilla ; Models, Anatomic ; Software ; Stress, Mechanical ; Weight-Bearing ; physiology ; X-Ray Microtomography ; methods