Construction of different kinds of prostheses on irradiated bone tissues after tumour surgery is a complicated part of modern implantology. In irradiated regions of the jaws where the bone layers are thin and the blood supply also is minimal, knowledge of the impact of each dose of radiation is very important. The aim of this study was to compare the bone response around titanium implants loaded with fixed bridges in dog mandibles irradiated with total doses of 40, 50 or 60 Gy. The results suggest that after irradiation with 40-50 Gy, when the dose is fractioned in order to achieve higher tolerance of the tissues compared with single dose irradiation, titanium implants may become osseointegrated in the mandibles. For high success rates, however, careful planning of radiotherapy and selection of implantation site with an adequate blood supply are essential.

Limited bone height restricts the use of long dental implants, so short implants may be selected in these situations. Recent reports on clinical results with short implants have been negative, however, and have suggested that indications for the use of these implants are limited. To verify these findings, a multicenter study of short ITI implants was carried out. In a 6-year period 253 short implants with a length of 6 mm were placed into 126 patients, who were followed up from 1 to 7 years. Altogether 7 implants were removed; 6 of these were located in the maxilla and 1 in the mandible. The quality of survival was comparable with the clinical results of longer implants from the same implant system. Although the clinical results of these short implants were favorable, it is recommended that they be used in combination with longer implants, especially when used in the less dense bone that is often seen in the maxilla.

The purpose of this study was to investigate the resistance of titanium implants to horizontal forces in a sheep model. Twenty implants were inserted into the foreheads of 5 sheep, 4 implants on each animal. After a healing period of 3 months, abutments were mounted on the implants. After a further healing period of 3 weeks, the implants were loaded with a horizontal pull of orthodontic elastics. The force varied between 250 and 350 grams. The duration of loading was 3 months. After the loading period the animals were sacrificed and the forehead bones with implants were fixed in formalin and evaluated histologically. In the histological specimens no signs of infection or bone loss were found around the implants. The results of the present study encourage the use of titanium implants also in cases where constant lateral forces are present.

The treatment of zygomatic fractures varies among surgeons, and the cosmetic and functional results are frequently less than optimal. A treatment guideline based on a simple classification of zygomatic fractures is presented. The emphasis is placed on the indications for closed and open reduction, consistent methods of three-dimensional alignment and fixation, and the management of concomitant infraorbital rim and orbital floor fractures. Postoperative results with regard to infraorbital nerve and maxillary sinus dysfunction, malar asymmetry, and orbital complications in the treatment of 1,025 consecutive zygomatic fractures are presented.

This investigation was planned to detect the ability of radiated bone to integrate with dental implants and to study the load-bearing capacity of these implants. In five beagle dogs, the premolars were extracted, after which one side of the mandible was radiated with 40 Gy. Three months later, two hollow-cylinder implants were placed on each side of the mandible. After a three-month period of osseo-integration, bridges were constructed on the implants, and they were loaded for six months. Both clinical and x-ray examinations showed that all implants had integrated well and bore load without change in their host sites for a six-month period, at which time the dogs were killed.

The THORP system is designed for bridging mandibular defects and for internal osteosynthesis of mandibular fractures. The major aspects and advantages of the THORP system compared with the conventional reconstruction plates and screws are: 1. The rigid fixation of the head of the screw to the plate, thus avoiding unphysiological loads to the bone underneath the plate. 2. The titanium-plasma coated and perforated hollow screws enable the development of direct bone-titanium contact at the area of the thread as well as the ingrowth of bone into the lumen and perforations. Further advantages are the preservation of small fragments such as the condylar process with only two screws and the stable fixation of bone transplants. The specially designed freely adjustable condylar prosthesis guarantees a correct guidance and function of the lower jaw. The fixation of this system to the lingual aspect of the jaw is particularly significant avoiding decubitus and perforation of the skin in the chin area. The results and the complications of 141 reconstructions of the lower jaw are discussed.

The subject of this paper is the evaluation of the advantages pertaining to the THORP (titanium hollow screw reconstruction plate) condylar prosthesis for reconstruction after hemimandibulectomy and exarticulation. The THORP condylar prosthesis is three-dimensionally adjustable, enabling the intraoperative meticulous functional adaptation of the condyle. Various designs of the condyle make it possible to achieve optimal congruency between the articular fossa and condyle. The anchorage of the prosthesis to the stump of the mandible is achieved with perforated hollow-screws rigidly fixed to the plate, thus producing optimal functional stability. The long-term follow-up of eleven cases, reconstructed with this system, confirmed the correct guidance and functional efficiency of this type of condylar prosthesis.

The surgical treatment of 26 patients with ankylosis of the temporomandibular joint, as well as various methods and materials used for functional restoration are described. The significance of radical removal of the ankylotic bone, as well as the advantages of the interpositioning of the lyophilized cartilage, are emphasized.

In this paper the surgical management of TMJ dysfunction-ankylosis and arthropathies-is described. The surgical techniques and the necessity of wide exposure are pointed out. Only thus are correct reshaping of the condyle, repair of the disc and radical resection of ankylotic bone tissue possible. The indication for prosthetic substitution to be interpositioned in cases with discal atrophy and perforation is discussed. There were no cases of facial paresis and no recurrence of ankylosis. The results, in regard to the functional aspects, confirm the efficiency of the methods described.

In severe craniofacial injuries, the involvement of the skull base with concomitant major dural tears is significantly high. Our methods and treatment plan are controversial compared with the conventional procedure: primary urgent neurosurgical exploration and repair with deferral of maxillofacial reconstruction. To avoid the disadvantages of the transfrontal intracranial management of the skull base, we modified the transethmoidal approach so as to enable the subcranial exposure of all the anterior fossa planes, including the sellar-sphenoidal region. The advantages rendered by this method are the feasibility of an early one-stage craniofacial reconstruction and avoiding retraction of the frontal lobes and damage to the olfactory filaments. The reduction of pseudohypertelorism, the decompression of the optic nerve, and the meticulous reconstruction of the midface and skull base are performed in one session and are regarded as one entity. The results of the surgical management of 395 craniofacial injuries and the low rate of complications emphasize the advantages of the methods described in this article.