Deutsche Zeitschrift fur Mund-, Kiefer- und Gesichts-Chirurgie最新文献

Temporary relining materials and surgical packs placed in a very intimate, direct contact to the adjacent epithelia or even wound surfaces are frequently used in dental and even more so in maxillofacial treatment procedures. Most of these materials, however, are not designed for this purpose; the results are inflammations and irritations. This study focussed on the cytotoxicity of the most frequently used temporary relining materials using the Erlangen ciliate test. This test method has been frequently used in various situations to determine the cytotoxic and cytostatic properties of substances and materials. It is based on liquid pure cultures of the eukaryotic monocellular organism "Tetrahymena piriformis". The sensitivity of these ciliates to cytotoxic noxae is rather similar to that of human and animal tissue cultures. Considerable differences in cytotoxicity have been observed.

A computer-aided three-dimensional reconstruction of a tooth-germ with hereditary opalescent dentine for the first time permitted to delineate the characteristic large dentinal canals as being of canal-like shape and to show their spatial relationship to the dentinal contour. The tubules often displayed links to pulpal tissue and extended from pulpo-dentinal junction up to the outer layer of dentine. The results of this study support the hypothesis of a vasal origin of these tubules.

This stereotactic method permits the localization of any radiographically visible foreign body in the maxillofacial hard and soft tissues. Stereotactic needles can be inserted either via an intraoral or an extraoral approach. Use of these needles as guides during tissue preparation allows simple exposure and subsequent removal of foreign bodies. A close cooperation between neurosurgeons and maxillofacial surgeons during this procedure is recommended. The technique is explained with the aid of 2 case reports.

Dividing the facial profile into three sectors according to the principle of the golden section with one circle around the auditory meatus as the center provides a basis for a harmonic profile. An additional important factor for the general harmony of the profile is the nose. Based on a great number of measurements, computer programs allow preoperative profile simulations and the assessment of surgical feasibility. As numbers and the resulting numerical relationships play a fundamental role in the classification of the human body, it is possible to express beauty in terms of geometry. It is, however, only at certain definite numerical relationships of these three facial sectors to each other that a harmonic profile of the human head is produced. The resulting constructive ideals of beauty provide aids and guidelines in plastic surgery.

The comprehensive treatment of extremely severe malocclusion, carried out up to now in more than 30 patients, is described step by step. After the removal of the third molars, orthodontic treatment is provided to align the arches. This is followed by 4 weeks of bite plane treatment to bring back the TMJ condyles into their physiologic position, which is usually lost because of the undefined occlusal relationship. Following cephalometric analysis the surgical treatment plan is established on the basis of lateral cephalometric films aimed at orthognathic repositioning of the mandible and the maxilla. In addition, the one-stage bimaxillary correction is simulated in the articulator for the construction of occlusal splints. The intraoperative use of these splints and the fixation of the condyles at the zygomatic bone via positioning plates allows, for the first time, the reproducible physiologic adjustment of the condyle during the entire length of the operation. This method also permits three-dimensional control of the position of the repositioned maxilla. The functionally stable fixation of maxilla and mandible makes long-term postoperative immobilization unnecessary.

The complete preservation of the original characteristics of donor tumors after xenografting into nude mice is more and more doubtful. With the aid of traditional biological methods and computer-assisted microscope image analysis the original human tumor tissues, including primary and recurrent tumors and metastases, are compared with nude mouse-grown xenografts. Squamous cell carcinomas of the oral mucosa served as original tumor tissues. Tumor takes were observed in 7 out of 12 cases. 5 transplantable lines could be established. Primaries, recurrent tumors and lymph node metastases are suitable for transplantations into nude mice and yield a comparable success rate. With one exception complete conformity between the original human tumor tissues and nude mouse-grown tumors could be found regarding the degree of differentiation and keratinizing tendency. As to the growth pattern of xenografts characterized by continuous shortening of growth periods, certain variations in the biological properties due to selection processes cannot be excluded. The results of microscope image analysis based on 35 different parameters suggest important differences within the developmental tendency of human tumor tissues and nude mouse-grown xenografts.

The regeneration of osseous tissues after simultaneous implantation of rat osteoblast-like cells cultured in vitro and pyrolyzed calf bone was investigated. In this study a cell line of rat osteoblast-like cells originating from explants of 2 inbred rats (Lewis) was established and cells were characterized. The osteoblast-like cells were cultured in vitro, embedded in bovine bone gelatine after 3 passages in culture and then implanted together with pyrolyzed calf bone in artificial femur defects of the inbred Lewis rats. After 10, 20, 40 and 80 days animals were sacrificed and the treated femora were taken for histological examination of bone growth. It was demonstrated that the cultured osteoblast-like cells showed an activity by forming extracortical bone, but had no measurable effect on bone growth pattern in the defects. Since our former animal study on reimplantation of osteoblast-like cells had revealed an effect on the cells on bone growth pattern, it is discussed whether the present lack of this effect can be explained by simultaneous implantation of xenogenic bone. In view of the importance of bone regeneration, autologous reimplantation of cultured bone cells deserves further investigation.

The altered structure of "Turner-teeth" was examined under the scanning electron microscope. The enamel surface revealed developmental disorders such as bowl-shaped pits, Tomes' process pits and enamel craters with rounded borders. On the fractured surfaces of yellowish discolored enamel, localized islands of pathological enamel were found. The enamel rods were atypically arranged and poorly mineralized. Surprisingly the prisms formed later by the same ameloblast often exhibited a entirely normal structure.

Carcinomas of the oral mucosa are colonized by a variety of aerobic and anaerobic bacteria. Apart from the normal flora of the oral cavity also organisms of pathogenic potential are found, which may cause postoperative wound infections. A specific antibiotic prophylaxis regimen in extensive head and neck surgery requires identification of the pathopotent organisms and sensitivity testing followed by perioperative individual antimicrobial chemoprophylaxis management. The results of an additional bacteriological examination of the surrounding pharyngeal flora showed no major difference to the range of organisms found in the carcinoma.

99 patients treated for bilateral retinoblastomas in the University Hospital of Essen between 1965 and 1983 were followed up for midface growth inhibition for an average period of 15 1/2 years. Depending on the type of treatment employed the patients were divided into four groups: Local tumor treatment using cryotherapy or laser techniques, ophthalmectomy alone, radiotherapy alone, and combined ophthalmectomy and radiotherapy. Statistically significant differences between the treatment groups were found regarding such symptoms as hypoplasia of the zygomatic bone, hypoplasia of the transversal orbit, hypoplasia of the temporal fossa, hypoplasia of the root of the nose as well as hypotelorism and enophthalmos. Combined surgery and radiotherapy caused the most severe growth disorders, followed by radiotherapy alone and ophthalmectomy alone. With local treatment detectable growth disorders were observed, if at all, only as a result of contralateral radiation scatter. Orthovoltage radiotherapy was found to produce growth disorders of significantly higher severity than megavoltage radiotherapy.