Objective To investigate imaging characteristics of human skin in different sites by using 20-MHz and 50-MHz high-frequency ultrasonography,and to compare the reliability of skin thickness measurement by the above two approaches of ultrasonography.Methods A total of 39 healthy volunteers aged 18-39 years were enrolled into this study.Then,20-MHz and 50-MHz ultrasonography were separately performed to image 20 different sites on the body,and the thickness of the epidermis and dermis were measured and evaluated by 3 dermatologists independently.The ultrasonic images were analyzed,and the intraclass correlation coefficient (ICC) was used to assess and compare the reliability of skin thickness measurement by 20-MHz and 50-MHz ultrasound.Results The ICC values were less than or close to 0.7 in epidermal thickness measurement at almost all the tested sites between 20-MHz and 50-MHz ultrasonography,suggesting poor reliability.However,20-MHz and 50-MHz ultrasonography showed excellent reliability in dermal thickness measurement with the ICC greater than 0.75 at almost all the tested smooth and flat body sites.The 20-MHz ultrasound could provide clear images of the dermis and subcutaneous tissue,while 50-MHz ultrasound could only provide clearer images of the dermis in details.In some uneven sites with complex anatomical structures,20-MHz and 50-MHz ultrasound probes had their own advantages and disadvantages in imaging depth and detail resolution.Conclusions The 20-MHz and 50-MHz ultrasono-graphy both can serve as non-invasive imaging techniques to show structures of the epidermis and dermis better.In different parts of human body,ultrasound frequencies should be selected according to their imaging characteristics.

Sixteen goats with fractures of right femur received cortical bone plates allografts on both the sides of femurs. The right allograft strut endured the stimulation of physiological stress, and the left allograft strut did not. Groups of goats were sacrificed and specimens were procured at 3, 6, 12, and 24 week after surgery for histology observation and image analysis of the vessels after Chinese ink perfusion, the rate of bone porosity, the integrated optical density (IOD) of tetracycline fluorescence labeling and new bone formation were investigated in order to evaluate the incorporation of the allograft strut. The allograft strut revascularized at 6 weeks after surgery in the fracture group, but at 3 weeks in the control group. The rate of area of vessels after Chinese ink perfusion, the rate of bone porosity, the integrated optical density (IOD) of tetracycline fluorescence labeling and new bone formation in the fracture group were worse than control from 3 weeks to 6 weeks, but the observed and measured values were better in the fracture group than in the control group beyond 6 weeks after surgery (P < 0.05). The stimulation of stress would be harmful to the allograft strut if the strut endured the stress at an earlier period postoperation. Yet, it would be beneficial to the revascularization, new bone formation, substitution, and internal re-building on the strut provided that the extremity was immobilized for 6 weeks; and if the cortical graft endured the stimulation of physiological stress from 6 weeks postoperation till cancellous conjunction between the ends of fractures, the revascularization on the allograft strut and the bone conjunction between partially allograft strut and host would be faciliated.
Allografts ; Animals ; Biomechanical Phenomena ; Bone Plates ; Bone Transplantation ; Femoral Fractures ; Femur ; physiology ; Goats

Objective:To investigate the effect of different crown heights of lateral incisor and canine on smile esthetics perception between orthodontists and patients.Methods:A total of 31 orthodontists and 56 patients on smile aesthetics perception were investigated.We adjusted the height of lateral incisor and canine to get 20 kinds of anterior tooth area morphology by Photoshop and asked interviewees to grade.Scores of satisfaction were recorded by Likert method.Results:Subjects in the 2 groups preferred smiles with upper anterior teeth edge parallel to lower lip.There was better acceptance for longer canines and less satisfaction at shorter lateral incisors in patients.Patients also got higher discrete degree of evaluation results and more rigorous about smile esthetics than orthodontists.Conclusion:Orthodontists and patients have different satisfaction at esthetics of anterior teeth.Esthetics preference should be considered in orthodontic treatment schedule.

Objective The aim of our work is to characterize individual normal occlusions to establish appropriate treatment standards for different vertical facial types. Methods A total of 30 patients with near-normal occlusion were grouped into high-angle group (eight cases), medium-angle group (12 cases), and low-angle group (10 cases) according to vertical facial skeletal type. Invivo5 software was used and digital imaging and communications in medicine data were rebuilt to measure the ∠L1/MP, ∠L6/MP, axis corner of L6, cant of occlusion plane, Balkwill angle, and Bonwill triangle of each group. Results Among the groups, the low-angle group had the smallest ∠L6/MP (P<0.05) and largest cant of occlusion. No significant difference was observed among the three groups with regard to the other parameters (P>0.05). Conclusion Patients with low-angle vertical facial skeletal type requires a modified treatment standard. In this group, the treatment standard must ensure that the cant of occlusion plane is more parallel to the Frankfurt horizontal plane compared with those of the other groups, and the axis of L6 is tilted distally relative to the mandibular plane.

To observe three-dimensional changes of dentigerous cyst-associated maxillary canines (DCAMC) in adolescents after marsupialization by using cone beam computed tomography (CBCT).
 Methods: A total of 34 DCAMC patients with dentigerous cyst aged 10-14 were divided into central type and lateral type, while canines on the non-cyst side served as a control. A three-dimensional reference frame was set up to analyze the position, angle changes and influential factors for DCAMC by using CBCT before operation and in 3-6 month after operation.
 Results: 1) Compared with pre-operation, there was significant vertical movement in DCAMC after marsupialization. Tip of tooth moved labially while tooth axis inclined mesiodistally; 2) Horizontal, vertical movement and mesiodistal inclination of DCAMC were significantly greater than those in the health side; 3) Compared with the lateral type DCAMC, the central type DCAMC showed a significant changes in labial inclination; 4) Horizontal movement, mesiodistal and labial inclination of lateral type DCAMC were all evidently greater than those of the central type DCAMC; 5) Vertical movement and inclination of DCAMC after marsupialization were significantly correlated to the time interval (r=0.354, 0.374, both P<0.05), while vertical movement of cuspid in health side was significantly negative correlated with the patients' age and the level of root formation (r=-0.506, -0.721, both P<0.01).
 Conclusion: DCAMC in adolescents can obtain obvious changes in position and angles after marsupialization regardless of the level of root formation, which is beneficial for further orthodontic treatment.
Adolescent ; Child ; Cone-Beam Computed Tomography ; Cuspid ; Dentigerous Cyst ; Humans ; Maxilla

To investigate three-dimensional morphological features of temporomandibular joint in skeletal malocclusion Class III with different vertical skeletal facial types.
 Methods: A total of 46 adults with skeletal malocclusion Class III were enrolled and allocated into a normal-angle, a high-angle and a low-angle groups. All patients were undergone cone beam computed tomography (CBCT). Images of temporomandibular joint were reconstructed and analyzed by Invivo 5. Nine measurements relevant to the positions and forms of condyle as well as joint spaces were performed.
 Results: Significant differences were not observed between the 2 sides of each group among skeletal malocclusion Class III (P>0.05). Compared with the high-angle and normal-angle patients, the low-angle patients had larger superior spaces, bigger gradients of the articular tublecle, longer condyle, and larger internal spaces between the condyle and the fossa. Compared with the low-angle and normal-angle patients, the high-angle patients had smaller condylar antero-posterior diameters.
 Conclusion: Class III malocclusion patients with different vertical skeletal patterns have different positions and forms of condyles, which should be paid attention to in clinic.
Adult ; Cone-Beam Computed Tomography ; Face ; diagnostic imaging ; Humans ; Image Processing, Computer-Assisted ; Malocclusion, Angle Class III ; diagnostic imaging ; Mandibular Condyle ; diagnostic imaging ; Temporomandibular Joint ; diagnostic imaging