ISSN:1049-2275    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

&NA;Ethics: The science of morals; the department of study concerned with the principles of human duty; the moral principles or system of a particular leader or school of thought; the moral principles by which a person is guided; the rules of conduct recognized in certain associations or departments of human life.—Oxford English Dictionary

ISSN:1049-2275    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

&NA;The aim of this study was to evaluate on‐line performance of a real‐time digital imaging system based on amorphous silicon technology and to compare it with conventional film‐screen equipment. The digital detecting imager consists of (1) a converter, which transforms the energy of the incident X rays into light; (2) a real‐time digital detecting system, capable of producing as many as 10 pictures per second using a large‐area pixel matrix (20 × 20 cm2) based on solid‐state amorphous silicon sensor technology with a pitch of 400 &mgr;m; and (3) appropriate computer tools for control, real‐time image treatment, data representation, and off‐line analysis. Different phantoms were used for qualitative comparison with the conventional film—screen technique, with images obtained with both systems at the normal dose (used as a reference), as well as with dose reduction by a factor of 10 to 100. Basic image quality parameters evaluated showed that the response of the detector is linear in a wide range of entrance air kerma; the dynamic range is higher compared with the conventional film—screen combination; the spatial resolution is 1.25 lp per millimeter, as expected from the pixel size; and good image quality is ensured at doses substantially lower than for the film‐screen technique. The flat‐panel X‐ray imager based on amorphous silicon technology implemented in standard radiographic equipment permits acquisition of real‐time images in radiology (as many as 10 images per second) of diagnostic quality with a marked reduction of dose (as much as 100 times) and better contrast compared with the standard film technique. Preliminary results obtained with a 100‐&mgr;m pitch imager based on the same technology show better quality but a less substantial dose reduction. Applications in craniofacial surgery look promising.

ISSN:1049-2275    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

&NA;Surgeons are used to obtaining bone grafts of calvaria, which are abundant and available. The outer table of the parietal bone can be split, usually at the level of the diploic interstice, with an osteotome. Inadvertently violating the inner table and the dura leads some surgeons to avoid using the outer table in the elderly. Sullivan and Smith measured the thickness of the outer tables, diploe, and inner table of 37 cadavers (average age, 59 years) and found each layer to be well preserved distinctly. However, they suggested that calvaria become brittle in patients older than 50 years of age. The current authors hypothesized that diploic composition is not changed, even in the elderly. The thickest part of the parietal bone of 49 Koreans and 30 whites were acquired, and undecalcified slides were made. Via light microscopy, using the National Institutes of Health image, the following measurements were made: the thickness of the parietal bone (PT), outer table (OT), diploe (DT), and inner table (IT); trabecular bone volume percent (TBV); trabecular thickness (TT); and trabecular separation (TS). There was no significant difference in the thickness of the OT, DT, and IT of the PT, TBV, TT, and TS among different ages. The PTs of women were thicker than men's. The PTs of whites were significantly thicker than Koreans'. This study disclosed that the DT is not different among varying age groups and is not sclerosed in the persons older than 80 years, and the OT of these individuals is not brittle. Thus, surgeons do not need to hesitate when taking the OT of the PT in older patients. However, the selection of the site is attentive to PT. The thickest posteromedial part of the PT is favorable and safe as a donor.

ISSN:1049-2275    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

&NA;Bone morphogenetic proteins (BMPs) are capable of inducing endochondral bone formation when applied on biologic carriers in numerous mammalianin vivoassay systems. Bone morphogenetic protein gene therapy is also currently being developed to promote osteogenesis for clinical indications such as spinal fusions, craniofacial bone loss, and osteoporosis. In this study, critical‐sized mandibular defects were treated with a control adenoviral vector (Ad‐&bgr;‐gal), a BMP‐2 adenoviral vector (Ad‐BMP‐2), or a BMP‐9 adenoviral vector (Ad‐BMP‐9). Gross tissue examination, radiographic analysis, and histologic analysis demonstrated significant bony healing in the BMP treated groups compared to controls. Osteogenesis was limited to the bony defect, without extension into the surrounding soft tissues. The study suggests that with further development, BMP gene therapy may be potentially useful for repair of bony defects in the craniofacial region.

ISSN:1049-2275    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

&NA;Various interpretations of clinical and cephalometric data lead to different diagnostic and surgical planning in the study of dentoskeletal malformations. Many authors have identified this discrepancy as an incorrect positioning between the skeletal structures and the Frankfurt plane (PFH)—a plane that is used routinely for the sagittal measurement of the upper and lower jaw. The aim of this study was to establish a control method to verify the correct positioning of the sella‐nasion point plane (SN) and the PFH. To find a reference plane, the authors concentrated their attention on measuring the intersecting angles between these two planes and the vertical posterior maxillary (PM) plane. Fifty patients (33 women and 17 men), all of whom were aesthetically and structurally harmonious class I dentoskeletal types, were analyzed using this method. Student'st‐test, the Kolmogorov‐Smirnov test, and Fisher's F‐test were used for statistical analysis. The results were compared with those proposed by the University of Michigan. To achieve a correct diagnosis and to obtain good functional and cosmetic results in the treatment of these kinds of malformations, it is necessary to make use of the PM vertical plane during cephalometric analysis.

ISSN:1049-2275    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

&NA;Browsing through some literatures, I happened to find out some records on the rite of imitation of the child's head to brachycephaly. In 1976, two skulls showing extraordinary forms were excavated out of an ancient tomb at Yean village of Daedong township in Kimhae County in Kyungnam Province, the Republic of Korea. The deformation in Yean village is judged to be an intentional frontal flattening. The frontal bone of deformed individuals is remarkably flattened by a primary deforming force. The parietal bone expands laterally and superoposteriorly as a major compensatory growth. The lambdoid or occipital flattening induced by the counterforce is light and unstable. In the facial skeleton, the maxilla shifts downward as a minor compensatory growth. These findings might be substantially correspondent to the custom in the southern area of Korea in the 4th century A.D. paragraphed by Han chuan of Wei‐dynasty record,History of the Three Kingdoms.It described that the people gave a pressure onto the child's forhead with stones in order to mold it for preference. Flatheaded meant “free” among the Chinook and Salish tribes of American Indians. Babies of slaves were denied the year‐long beauty treatment—a board tied to the infants' padded skull—that permanently flattened the foreheads of tribal members. Referring to these records, I presume that brachycephaly can be induced by direct extrinsic pressure at least until the soft infant's head gets hard.

ISSN:1049-2275    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

&NA;Benign lymphangiomas are encountered frequently in the head and neck region. They may be well circumscribed or diffusely invasive, involving subcutaneous tissue and underlying muscle, and consist of dilated, thin‐wall sinuses. Surgical therapy with excision as wide as possible, while taking care to avoid rupturing the lesion, is the treatment of choice. To simplify complete excision, the authors introduce an intraoperative technique—intralesional injection of fibrin glue. Using this technique over period of 10 years in 27 patients (age range, 7‐24 years) they removed successfully intra‐ and extraoral lymphangiomas. There have been no recurrences. This technique helps avoid rupture of the epithelium and bleeding, and makes it easier to remove lymphangiomas surgically and as completely as possible. This technique reduces recurrence remarkably and ensures successful surgical excision.

ISSN:1049-2275    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

&NA;Hemimandibular hyperplasia is a well‐defined, rare asymmetrical mandibular malformation. It is characterized by diffuse enlargement of the condyle, the condylar neck, and the ramus and body of the mandible. Because the anomaly begins before puberty, it is understandable that the maxilla follows the downward growth of the mandible. Pathogenesis is due most likely to clear hyperactivity in the condyle, which can be documented histologically with an actively proliferating cartilage. Therapy is largely based on the patient's age. The authors present their series of nine individuals with hemimandibular hyperplasia treated with various surgical methods between 1992 and 1994. A therapeutic approach calledorthopedic maxillary managementapplied to two of the nine patients is presented. The objective is to maintain the occlusal maxillary plane in a correct position in growing patients. All clinical results, except one, were satisfying and showed good postoperative stability.

ISSN:1049-2275    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

&NA;The ability to avoid a subsequent bone graft makes the use of gingivoperiosteoplasty (GPP) at the time of cleft lip repair an attractive technique. The use of GPP, in combination with presurgical orthodontics, has been shown to result in successful bony union in the majority of patients. However, secondary bone grafting is still necessary in 30% to 40% of patients due to persistent alveolar bony defects. The elucidation of methods to improve the success rates of these procedures has been hampered by the lack of reproducible animal models. The purpose of this study was, therefore, to develop a rodent model of GPP that would facilitate the investigation of methods to improve osteogenesis in alveolar defects. We report a surgically produced rat model (9 × 5 × 3‐mm alveolar defect) that is reproducible, inexpensive (relative to large‐animal models), and simple technically. In addition, healing in this model occurs in a predictable manner during a 12‐week period, thus enabling analysis of methods designed to accelerate or facilitate osseous regeneration.

ISSN:1049-2275    

出版商:OVID    

年代:2000

数据来源: OVID