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Biomedical subjects

R Ewers

Publications and source records attributed to R Ewers.

At least 127 records · Page 7Linked to original sources
PubMed1980

[Horseshoe-shaped osteotomy with bone interposition in order to raise the maxillary crest. An operating method stopped after the experiment].

An attempt was made to systematize a maxillary osteotomy to raise the maxilla using ten macerated skulls and two fresh cadavers with endentulous astrophied maxillas. The splayed vestibulum of the maxilla was depressed, and the flat palatine vault was arched. The complication rate in the experiment was so high that this operation must be rejected.

Alveolar Ridge Augmentation↗
PubMed1979

Photoelastic experiments on the implantation of a bone graft into the mandible with stable compression osteosynthesis.

The implantation of a bone graft into the mandible was simulated in photoelastic model tests. Problems posed by the lingual and alveolar areas untouched by the plate are discussed. The tests showed that in both problem areas enough interfragmentary pressure can be built up using a five-hold DC (dynamic compression) plate with a short implant and two four-hole DC plates with a long implant, whenever the metal plates have dynamic compression holes (DC), are prebent and the screws are in converging position. This is a prerequisite for a rapid revascularization of the implanted bone graft and primary bone healing. These tests and our clinical experience showed that with small implants using a five-hold plate and with long implants using two four-hole plates, and physiologically stressing the bone implant, the principles of stable compression osteosynthesis without intermaxillary immobilization have proved themselves.

Biomechanical Phenomena↗
PubMed1979

[Prosthetic aspects in the planning of progenia operations].

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.

Adolescent↗
PubMed1978

[Indications for surgical treatment of mandibular osteomyelitis].

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.

Bone Transplantation↗
PubMed1977

[Photoelastic studies for the fixation of osteosynthesis plates].

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.

Biomechanical Phenomena↗
PubMed1977

[Metal plate osteosynthesis and wire osteosynthesis for the treatment of periorbital fractures in an experimental study].

With consideration of the special situation in periorbital fractures, the fundamental differences between wire and metal plast osteosynthesis was demonstrated on the basis of mathematical calculations, mechanical considerations and tension optical experiments. We further report on the different behaviour of both methods of osteosynthesis in tension experiments which demonstrate the distinct superiority of the metal plate.

Biomechanical Phenomena↗
PubMed1977

[Temporary bridging of defects in mandibular resections with osteosynthesis methods].

In a survey, the three conventional methods of bridging a defect (immediate rib transplant, extraoral Becker splinting and intraoral metal plate bridging) are studied. The advantages and disadvantages of the pertinent method are described. Although metal plate bridging has risks and disadvantages, clinical experience has shown the great advantages of this temporary method in extensive mandibular resections with soft tissue covering the defect.

Bone Plates↗
PubMed1976

[Periodontal conditions of the teeth next to the fracture line after stable plate osteosynthesis in the mandible].

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.

Bone Plates↗