[Cranio-maxillofacial traumatology]. / Traumatologie van het aangezicht.

During the last 50 years, significant developments have taken place in the treatment of cranio-maxillofacial fractures. The aim of treatment is to achieve the most complete possible restoration of facial functions Epidemiologic figures for these fractures are sparsely available in the literature, but traffic accidents, acts of violence and sports injuries appear to be the main causes. Currently, treatment of facial trauma is aimed at early and (nearly) complete restoration of function. To achieve this goal almost exclusive use is made of stable osteosynthesis methods in The Netherlands. An optimal fixation method exists for nearly every cranio-maxillofacial trauma due to the availability of a large variety of osteosynthesis materials, from micro-plates to reconstruction plates.

Histology of human alveolar bone regeneration with a porous tricalcium phosphate. A report of two cases.

Porous beta-phase tricalcium phosphate particles (pTCP) (Cerasorb) were used in two patients to restore or augment alveolar bone prior to the placement of dental implants. In one patient, pTCP was used to fill a large alveolar defect in the posterior mandible after the removal of a residual cyst, and in another patient to augment the sinus floor. Biopsies were taken at the time of implant placement, 9.5 and 8 months after grafting, respectively, and processed for hard tissue histology. Goldner-stained histological sections showed considerable replacement of the bone substitute by bone and bone marrow. In the 9.5 months biopsy of the mandible, 34% of the biopsy consisted of mineralised bone tissue and 29% of remaining pTCP, while the biopsy at 8 months after sinus floor augmentation consisted of 20% mineralised bone and 44% remaining pTCP. Bone and osteoid were lying in close contact with the remaining pTCP and were also seen within the micropores of the grafted particles. Tartrate resistant-acid phosphatase (TRAP) multinuclear cells, presumably osteoclasts, were found surrounding, within and in close contact with the pTCP particles, suggesting active resorption of the bone substitute. Remodelling of immature woven bone into mature lamellar bone was also found. No histological signs of inflammation were detected. The limited data presented from these two cases suggest that this graft material, possibly by virtue of its porosity and chemical nature, may be a suitable bone substitute that can biodegrade and be replaced by new mineralising bone tissue.

Changes in the pattern of fractures of the maxillofacial skeleton.

This study reports on two groups of patients who sustained maxillofacial fractures and were treated at the Department of Oral and Maxillofacial Surgery, Nijmegen, The Netherlands. It spans the periods 1 January 1960 31 December 1974 (1379 patients) and 1 January 1975 31 December 1987 (1324 patients). The changes in the pattern of maxillofacial fractures (e.g. localization and frequency, etiology, age and sex distribution, associated injuries) are discussed. The striking reduction of "road traffic accidents" and the increasing influence of "violence" and "sports" are remarkable.

[Complications of the surgical treatment of the severely resorbed edentulous maxilla]. / Complicaties bij de chirurgische behandeling van de sterk geresorbeerde edentate bovenkaak.

Complications during reconstructive surgery for placement of endosseous implants in the severely resorbed maxilla are described, based on recent literature. Detailed long term follow-up studies on complications are lacking. Clinical experience has shown that this type of surgery is prone to complications. These complications must be taken into account when indicating and planning this type of surgery.

[Epidemiology of facial injuries]. / Epidemiologie van het aangezichtsletsel.

Epidemiological studies of maxillofacial trauma are numerous in the literature, but as a general rule their results are applicable to the investigated cohort only. Nevertheless, major differences in pattern of maxillofacial fractures have been reported between these studies. The longitudinal Nijmegen study (period 1960-1987) describes changes in the pattern of maxillofacial fractures for the Dutch situation. Traffic accidents still are the major cause of maxillofacial trauma, but the contribution of violent crimes and sports is rising. In addition, alcohol abuse as a factor in maxillofacial trauma has increased from 3% to 12% between 1960 and 1987. The current Dutch and international registration and classification systems need consent to allow for comparison of the results. Such systems should include ranking according to etiology, means of transport and age. Insight in the pattern of accidents, including maxillofacial trauma, will result in better ways of prevention of such accidents.

Clinical evaluation of mandibular overdentures supported by multiple-bar fabrication: a follow-up study of two implant systems.

A retrospective follow-up study was undertaken to assess the clinical condition, complications, and prosthodontic aftercare of two different implant systems over a long period. Thirty-six patients treated with a total of 135 ITI type F endosseous implants, and 37 patients treated with the transmandibular implants and a total of 146 transmandibular posts, were studied during a mean follow-up period of 70 months and 44 months, respectively. The choice of implant type was mainly influenced by a change in financial support by the National Health Insurance Company in The Netherlands in 1987. Cumulative success rates were calculated using the Kaplan-Meier product limit method. In the analysis, the risk for failure of the implants was adjusted for differences in mandibular bone height. There were no differences between the two treatment groups with regard to age, gender, period of edentulousness, and mandibular bone height. During the follow-up period, plaque, bleeding, and hyperplasia scores demonstrated no significant differences between the two groups. The ITI type F group showed significantly more recession, and the transmandibular implant group demonstrated significantly increased Periotest values. After adjusting for differences in bone height, patients treated with ITI type F implants had a lower risk of failure (relative risk, 0.55; 95% confidence interval 0.32 to 0.95). However, neither of the implant systems fulfilled Albrektsson's criteria of success.

[Dental ITI-implants in the Netherlands: The evaluation of 2454 implants]. / ITI-implantaten in Nederland. Evaluatie van 2454 implantaten.

Between 1982 and January 1991, 2454 ITI Bonefit implants were placed in 841 patients. The clinical data were gathered from the departments of oral and maxillo-facial surgery at hospitals in Breda, Leiderdorp and Zwolle, the Netherlands. The follow-up ranges from one year to 9.5 years. A total of 48 implants were lost (2%).

[Type F hollow cylinder implant (I.T.I.)]. / Het holle cylinder implantaat type F (I.T.I.).

The single hollow titanium cylinder implant type F is here described. From october 1983 till october 1988, 187 implants were placed in 56 patients. It is possible to use this implant as a replacement for a single tooth or as abutment for a bridge. In case of extreme bone loss of the edentulous jaw, this implant is suitable to create retention and stabilisation for a denture. Up till now 180 implants are in function (96%); 7 implants were lost because of early failures.

[The single, hollow titanium cylinder implant (I.T.I.)]. / Het holle cilinder titanium implantaat type F (I.T.I.).

In cases of extreme bone loss of the edentulous jaw, nowadays, implants are suitable to create retention and stabilisation for the dentures, next to the wellknown preprosthetic surgical techniques. It is also possible to use this implant as replacement of a single tooth or as abutment for a bridge. The single hollow titanium cylinder implant type F is described. Also the surgical technique for application of this implant is explained. In the period October 1983 till December 1987, 126 implants (39 patients) were placed; eight of them are removed (6%).

Detection of insulation failure by gradual reduction in noninvasively measured electrogram amplitudes.

Insulation failure of pacemaker leads may give rise to functional defects such as under- or oversensing, loss of capture or muscle stimulation. An increased incidence of such failures has been reported for the bipolar polyurethane-insulated Medtronic model 6972 pacing lead. It is therefore important to identify techniques that will detect such insulation defects early. A case report is presented in which diminishing electrogram amplitude at follow-up predicted lead failure several months before becoming clinically manifest. This finding suggests that routine measurement of such an electrogram may be a useful tool in predicting impending lead malfunction.