Combination of microplate and miniplate for osteosynthesis of mandibular fractures: an experimental study.

Because of the limited space available in the mandible, especially in the mental foramen and apical region, miniature osteosynthesis material is desirable. Recently, metal deposition in the direct neighbourhood of osteosynthesis plates made of titanium or even in peripheral organs have been reported in the literature with increasing frequency. The size and amount of osteosynthesis material used should therefore be kept to a minimum. In an experimental study on 60 models, we examined load-carrying stability and in a second series, torsional strength of two-piece plastic models connected by either a single miniplate, two miniplates, or a titanium microplate plus a miniplate. In our test arrangement, the average loading capacity of the combination miniplate/miniplate was 470 N: that of the combination microplate/miniplate was only 267 N. The test group with the single miniplate had an average loading capacity of only 225 N. Masticatory loads on the plates exceeding 200 N occur only 3 months after osteosynthesis. At that time the fracture has largely consolidated. The torsional strength of the microplate/miniplate combination was similar to that of the miniplate/miniplate combination (1,000 Nmm resulting in a width of the gap measuring 0.8 mm and 0.5 mm, respectively). The single miniplate was considerably less stable (0.8 mm gap width as early as with 300 Nmm). According to Champy, rotational forces in the anterior region of the mandible amount to approximately 1,000 Nmm and need to be withstood by the osteosynthesis material. Our results suggest that treatment of fractures in the interforaminal region with a combination of microplate and miniplate will be stable enough for early mobilization.

Ectopic submandibular thyroid tissue with a coexisting active and normally located thyroid gland: case report and review of literature.

Ectopic thyroid tissue in the submandibular space with the thyroid gland in its normal location is an extremely rare phenomenon. We present a case of a 75-year-old woman who had painless swelling in the left submandibular space and was referred to our hospital with the suspicion of having a malignant tumor originating from the submandibular gland. Histologic examination showed normal follicular thyroid tissue without any sign of malignancy. In general there are 3 explanations for the presence of ectopic thyroid tissue found in the submandibular region: (1) displacement during the course of embryonal development, (2) spread of tissue during surgery on a normally located thyroid gland, and (3) metastasis of a highly differentiated papillary thyroid carcinoma. We reviewed the literature with respect to the embryological background and the clinical management of such cases.

Surgical and orthodontic rapid palatal expansion in adults using Glassman's technique: retrospective study.

In 1984, Glassman et al. described a conservative surgical method of separation of the midpalatal suture in which an osteotomy is done only at the lateral and anterior wall of the maxilla. Between 1991 and 1997, we have operated on 21 patients with maxillary transverse discrepancies using the method that they described. This gave good results in 20 patients. The other, who was operated on at the age of 38 years, developed a fracture of the alveolar process of the maxilla on one side because of ossification of the midpalatal suture. The surgically assisted rapid palatal expansion described by Glassman et al. is suitable for patients up to the age of 30. Older patients require additional surgical separation of the midpalatal suture.

[Glassman palatine expansion. Experiences with mono- and bimaxillary dysgnathia operations]. / Gaumennahtsprengung nach Glassman. Erfahrungen bei mono- und bimaxillaren Dysgnathieoperationen.

The median palatine suture has long been regarded as having the greatest resistance to dilatation of the maxilla. In 1984 Glassman [3] presented a conservative-surgical method of division of the palatineal suture in which only the lateral and anterior support of the maxilla is debilitated surgically. An orthodontic apparatus cemented in place preoperatively is already used intraoperatively for dilatation of the maxilla. In the period from 1991 to 1997, 16 patients with a leptomaxilla and various dysnathic findings have been operated on at our clinic by the method described by Glassman. Sometimes the maxilla was dilated intraoperatively using the apparatus cemented in place by the method of Derichsweiler and dilatation was continued post-operatively until the described result was achieved. After successful dilatation of the maxilla and a stabilizing phase, a mono- or bimaxillary operation was performed. The use of this method led to the desired result in 15 patients. Dilatation of the maxilla was objectivized by determining the pre- and postoperative width of the anterior and posterior dental arch using models and X-ray of the occlusal overlay of the maxilla. In one patient who was operated on at the age of 38 years, a fracture of the alveolar process of the maxilla occurred unilaterally due to the completed ossification of the median palatine suture. The method of surgically aided dilatation of the maxilla at the level of Le Fort I plane is suitable for patients up to the age of 30. In older patients, the median palatine suture should be transsected as well.