Search

Copyright of Stomatologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Mund-, Kiefer- und Gesichtschirurgie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oral & Maxillofacial Surgery is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oral & Maxillofacial Surgery is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this study was to examine the clinical and histological bony healing process beneath titanium foils used for guided tissue regeneration as well as of the Frios Algipore graft which was applied with autologous bone. 66 sinus floor elevations were carried out and examined over a period of three years and eight months. A success rate of 64% was recorded with foil incorporation. Complications occurred in form of primary and secondary disturbances in the healing process caused by exposure of the foil. 12 of the 66 foils had to be removed early. In all but one case, the augmented bone material was macroscopically well integrated despite the loss of the foil. Primary stability of the inserted dental implants into the ossified augmented site after operations of the sinus maxillaris was reached in all cases with absence of post-operative complications, and in 94% when there was postoperative exposure of the membrane. Histologically, a thin layer of connective tissue poor in cells but rich in collagen fibers appeared underneath the titanium foil. This was followed by newly-formed bony tissue transforming into osseous lamella parallel to the membrane underneath the new periost. In 65 out of 66 cases a sufficient amount of stable bone was built up locally suggesting good bio-compatibility and barrier function. Further, the foil also provided mechanical rest and supporting function for the space underneath. However, the occurrence of healing complications in 36% of the cases showed a need to improve on the titanium foils.

A new approach to addressing difficult tissue reconstructive or replacement problems in the oral cavity is to engineer new tissue by using selective cell transplantation on polymer scaffolds. The current study characterized the osteoblastic nature of adherent mandibular cells on biomaterials, which could have a potential use as scaffolds for tissue engineering strategies. Cells of mandibular origin from one patient were cultivated on three different biomaterials (PepGen P-15 trade mark, Frios Algipore, and OsteoGraf/LD-700) for 7 and 14 days and osteocalcin expression was demonstrated by RT-PCR and SDS-PAGE/Western blotting. In order to explicitly characterize only the adherent cells on the biomaterials, we first separated the biomaterials with adherent cells from the culture plate before trypsinization. We could demonstrate that cell growth of adherent mandibular osteoblast-like cells was significantly higher on biomaterials with an organic component (PepGen P-15 trade mark ) in comparison to Frios Algipore and OsteoGraf/LD-700, respectively. In conclusion, only the explicit study of adherent cells at the gene and protein levels gives information about the osteoconductivity of biomaterials.

In this paper, a recently developed computer-based dental implant positioning system with an image-to-tissue interface is presented. On a computer monitor or in a head-up display, planned implant positions and the implant drill are graphically superimposed on the patient's anatomy. Electromagnetic 3D sensors track all skull and jaw movements; their signal feedback to the workstation induces permanent real-time updating of the virtual graphics' position. An experimental study and a clinical case demonstrates the concept of the augmented reality environment--the physician can see the operating field and superimposed virtual structures, such as dental implants and surgical instruments, without loosing visual control of the operating field. Therefore, the operation system allows visualization of CT planned implantposition and the implementation of important anatomical structures. The presented method for the first time links preoperatively acquired radiologic data, planned implant location and intraoperative navigation assistance for orthotopic positioning of dental implants.

Human tumor cells from 22 patients with squamous cell carcinomas of the oral cavity were cultivated in vitro and then subjected to sensitivity tests to cytotoxic drugs such as methotrexate, 5-fluorouracil, cisplatin and bleomycin. Tumor cell proliferation showed drug-specific reaction patterns and time-dose-dependent variations. While the effect of methotrexate on cell proliferation was insignificant, 5-fluorouracil caused a growth suppression of 50%. Cisplatin and bleomycin suppressed cell growth by more than 90%.

A three-dimensional model of articular disk dislocations has been developed. Histological examination of 35 temporomandibular joints in near sagittal section reveals sometimes extreme anterior displacement in about 50% and slight posterior displacement of the disk in 6% of the specimens. In the frontal plane medial dislocation prevails in more than 70% of the 32 specimens evaluated, whereas there is only one lateral dislocation. Within the predominantly medio-anterior direction of dislocation there are, however, variations. Excentric forces relative to the center of gravity of the disk always result in dislocations accompanied by rotation in the anterior or posterior part. Where the resulting forces apply on the center of gravity there is a translation in a medio-anterior direction.

In 60 patients with primary squamous cell carcinomas of the oral cavity, clinical examination was complemented by 5 additional diagnostic procedures prior to surgery to assess tumor extension. Comparing these finding with the histological evaluation of the excised tissue demonstrated that, while the TNM classification remains the foundation of all tumor diagnostic procedures, the use of radiography, bone scintigraphy and CT is indispensable to ascertain the amount of tissue to be excised. CT competes with B-scan sonography in cervical lymph node diagnostics. Tumor scintigraphy has been found to be an unreliable method.

A plan of treatment was worked out based on the current classification of osteomyelitis of the mandible. On the basis of clinical follow-up examinations between 1973 and 1977 and the use of improved diagnostic tools, it was shown that active surgical procedures have become more and more accepted in our hospital.

The concept of perioperative diagnosis and treatment of patients with chronic TMJ disease has been confirmed by a follow-up examination of ten female patients after surgical treatment. Eight of the ten patients were pain-free after observation periods of 3 to 20 months. Following an initial bite-guard splint therapy, instrumental functional analysis, MR tomography and arthrographic visualization of dynamic movement profiles are indispensable. The results have also shown that, depending on the intraoperative finding, a postoperative splint therapy should be performed for six months.

Because of the biomechanics of the mandible, several viewpoints must be considered in stable metal plate osteosynthesis. A particular AO mandibular dynamic compression (DC) plate with perforations in a 45 degrees arrangement ("Freiburg Zuggurtungsplatte") has been developed to create an interfragmentary pressure zone in the region of the teeth during function. Photoelastic experiments showed that interfragmentary pressure developed due to this arrangement of perforations. To avoid a gap in the lingual region distant from the plate and to enable interfragmentary pressure in this region during function, converging screws are discussed. Photoelastic experiments showed that by slight inclination of the screws in convergent position the interfragmentary pressure is already increased in the lingual fracture gap distant from the plate. For a better guide of the screws in convergent position, an alteration of the spheric DC slide hole should be considered.

Follow-ups in 21 patients with 30 fractures of the lower jaw which were treated with stable plate osteosynthesis showed that 94% of the teeth adjacent to the fracture line were not extracted. The rate of secondary healing was 7%. Evaluation of the periodontal conditions showed that only 14% of the teeth were not worth keeping and 45% of the teeth required treatment. It is pointed out that when treating mandibular fractures with stable plate osteosynthesis, retention of the teeth in the fracture line does not mean an increased risk as far as secondary healing and the tooth itself are concerned.

Operative planning for progenia is carried out using prosthetic principles. Correction of a malpositioned mandible, modelling of incongruent dental arches, functional distribution of piers, and a favorable interalveolar connecting line form the basis for stable occlusion and articulation. The fitting of a prosthesis later is simplified by such intensive interdisciplinary cooperation.

Various possible methods and own experimental approaches to the production of an autogenous, two-layer epithelialdermal replacement of the mucous membrane are reported. The results of the cultivation of human mucosal epithelia in vitro are presented and the basic requirements this material should meet are discussed.

Temporomandibular joint alterations were reported which were determined on the basis of reproducible preoperative and postoperative roentgenograms. The films were produced with the help of the Hanel. C arch in the transcranial, lateral oblique projection. Displacements were demonstrated particularly in the anterior and the caudal directions. This method however does not allow a definite statement to be made concerning the postoperative position of the condyles.

The regeneration and degeneration of the proximal and distal parts of the nerve resulting from damage to the alveolaris nerve by osteosynthesis screws was studied in animal experiments. Twenty-four rabbits were divided into two groups of twelve animals each. In group A, the osteosynthesis screws were left in the nerve during the three-month study; in group B, these screws were removed after one week. A significant difference in the regenerative ability of the inferior alveolaris nerve was noted between group A and group B. The clinical experience that early removal positively affects the regenerative ability of the nerve was confirmed.