Biomedical subjects
Publications and source records attributed to M Matejka.
OBJECTIVE: To present two case reports of the surgical correction of vaginal vault prolapse with prolene mesh. DESIGN: Case Report. SETTING: Department of Gynecology and Obstetrics, Hospital Nitra. METHOD: Description of surgical method. CONCLUSION: Sacral colpopexy is method of the choice for correction of vaginal vault prolapse in younger sexually active women.
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Following tooth loss, the maxillary alveolar ridge is affected by extensive resorption and its cancellous bone substance undergoes intense remodeling processes. This is particularly important for endosseous implant surgery as the primary stability and thus the prognosis of endosseous implants depends on the cancellous bone density and structure of the alveolar ridge. To analyze the structure of alveolar trabecular bone, 156 sections were obtained from 52 edentulous maxillae (29 female, 23 male; mean age: 72.5 years) from the lateral incisor, first premolar, and first molar regions. The structural histomorphometric analysis was performed on cancellous bone of the section surfaces using semiautomatic image analysis. The following parameters were measured: trabecular bone volume, trabecular number, trabecular thickness, trabecular plate separation and trabecular interconnection. All examined parameters showed an extreme range of variation. A difference of more than 45% between the highest (= 51.93%) and the lowest (= 6.73%) trabecular bone volumes was found. Furthermore, the measurements showed that trabecular bone volume, thickness and number were distinctly lower in the molar region than in the incisal and premolar regions. Significant sex-specific differences were found in all investigated regions, female maxillae showing a smaller amount and a lower connectivity of cancellous bone than male maxillae.
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Trabecular bone volume and trabecular connectivity (trabecular bone pattern factor) of edentulous mandibles were examined using undecalcified bone sections from the region of the 1st premolar to investigate atrophy-related changes in mandibular cancellous bone. The mean trabecular bone volume was 21.8% in female mandibles and 36.6% in male mandibles. The mean trabecular bone pattern factor was -0.22 mm-1 for female mandibles and -2.29 mm-1 for male mandibles. The difference between the sexes was statistically conspicuous for both parameters, but did not attain statistical significance. A notable fact was the extreme range of variation in both trabecular bone volume and trabecular connectedness. A difference of 65% between the highest and the lowest trabecular bone volumes measured in the present study (min, 7.6%; max, 73.6%, both male) reflects the possible variation in trabecular density of edentulous mandibles.
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Cyclosporine (CsA) is a selective immunosuppressant widely used in clinical therapy. Like phenytoin and nifedipine, the drug is associated with gingival overgrowth. This study considers the interaction of CsA and prostaglandin I2 (PGI2), in particular the action of the drug on gingival tissue in vitro and in vivo. The PGI2-synthesis of rat, rabbit and human gingival tissue was examined by bioassay. In vivo CsA-therapy reduces gingival PGI2-synthesis. The results furthermore show a dose-dependent inhibition of PGI2-synthesis by CsA (1-100 micrograms/ml) in vitro. PGI2-synthesis from in vivo CsA-pretreated probes was further dose-dependently diminished by in vitro addition of CsA. As PGI2 exerts an antiproliferative activity via cAMP-elevation, the drug-induced inhibition of PGI2 production is claimed to be responsible for gingival hyperplasia in CsA-treated patients.
From 47 anatomic specimens, vertical sections were cut in the molar region, and computer-assisted measurements of both height and width of the alveolar ridge were made to assess the available bone volume for endosseous implant placement. The mean ridge heights ranged between 9.30 and 3.23 mm, the highest and lowest values being 13.8 and 0.8 mm, respectively. The ridge widths generally proved to be sufficient for placement of endosseous implants. Small knife-edge ridges are rarely found in the posterior maxilla. Reduction of the cancellous portion of the posterior maxilla seems to be influenced by the duration of edentulousness, as well as by osteoporotic changes, without being directly related to ridge configuration and bone volume.
Soluble endothelial leukocyte adhesion molecule-1 (sE-selectin) levels in peripheral blood (PB) and gingival capillary blood (GCB) of both healthy donors (HD) and patients with adult periodontitis (AP) were assayed by ELISA. Binding of sE-selectin to polymorphonuclear neutrophils (PMN) from PB, GCB and crevicular fluid (GF), and expression of L-selectin and sialyl-Lewisx (sLex) on these cells were analyzed by immunofluorescence and flow cytometry. No significantly enhanced serum levels of sE-selectin in patients with AP, compared to HD (28 +/- 5 ng/ml vs 19 +/- 3 ng/ml, respectively), and no differences in the concentration of sE-selectin in GCB (16 +/- 1 ng/ml vs 16 +/- 2 ng/ml, respectively) were observed. On PB-PMN no significant differences in the expression of L-selectin and sLex were found and binding of sE-selectin to PB-PMN was comparable between HD and patients with AP. Binding of sE-selectin to GCB-PMN was significantly higher in patients with AP compared to HD (mean channel fluorescence (MCF) = 88.5 +/- 13.2 vs MCF = 24.2 +/- 5.3, respectively). The expression of sLex on GCB-PMN did not differ significantly between the two groups. A significant decrease in the expression of the adhesion molecule L-selectin on GCB-PMNs compared to PB-PMN was found in patients with AP but not in HD. CF-PMN showed decreased expression of both L-selectin and sLex compared to PMN from PB and GCB, both in HD and patients with AP. Taken together, these data suggest that PMN from patients with AP had reduced selectin-mediated adhesive capabilities to inflamed gingival endothelium.
Cyclosporine A (CsA) is a highly potent immunosuppressive agent that has proven to be particularly useful in organ transplantation. Like phenytoin and the calcium antagonists, this drug may be associated with gingival hyperplasia. This study examined the interaction of platelet derived growth factor (PDGF) with prostaglandin I2 (PGI2)--a potent mediator in inflammation and bone resorption. PGI2 synthesis was examined by bioassay in gingival tissue from rats, rabbits and humans. Gingival tissue from CsA-treated patients generates less PGI2. PDGF causes a dose-dependent increase in PGI2 release in both CsA-treated and control subjects. The actual and percentage increase in PGI2 synthesis, however, was significantly higher in control tissue. While PDGF on the other hand modulated cellular proliferation, it causes on the other hand liberation of PGI2 from gingival tissue, thus interfering with its own action and further synthesis. If the PGI2 response is insufficient as after CsA therapy, the proliferative action might dominate. These findings therefore suggest an important pathogenetic role of PDGF and possibly other growth factors in CsA-induced gingival hyperplasia. "CsA gingivitis" seems to be a predominantly proliferative process, whereby inflammatory reactions appear only as a secondary phenomenon.
In 25 edentulous anatomical mandible specimens (15 female, age range 69-90 years; 10 male, age range 68-88 years), the bone mineral content (BMC) was measured by dual-photon absorptiometry (DPA) and analyzed in a standardized area of the mandibular body. The results of our BMC examinations showed that there was a significant difference (P = 0.05) between the two sexes. Another notable fact was that, with advancing age, the values measured in the male mandibles tended to increase slightly but in a statistically significant way. Those of the female mandibles tended to decrease with age. A possible explanation for this observation may be derived from the fact that a reduction of the mandibular height leads to a reduction of the moment of resistance. As functional adaptation in order to preserve the stability of the atrophic body of the mandible, the amount of inner cortical bone of the male mandibles increases, leading to a reduction of the cancellous portion. In the mandibles of women, postmenopausal osteoporosis seems to prevent an analogous compensation mechanism.
The bone mineral content in a standardized site was measured in 25 edentulous mandibles with dual-photon absorptiometry. The results of the bone mineral content examinations demonstrated a significant difference between the sexes. With advancing age of the subjects, the values measured in the men's mandibles tended to increase slightly, whereas those in the women's mandibles tended to decrease. As a functional adaptation to preserve the stability of the male atrophic mandible, the amount of inner cortical bone is increased. Explanations for this observation are discussed. That the mandibles of men and women change differently with increasing age should be considered in routine examinations, because osteoporosis may be regarded as a cofactor of residual ridge resorption in women.
In 43 edentulous, lower jaw halves, sections were carried out in the area between the mental foramen and the third molar. The relative changes in the location and course of the mandibular canal which are caused by atrophy were analysed. For this purpose, the mandibles were classified according to so-called residual ridge orders which describe the different stages of alveolar ridge resorption. The following findings were obtained: The distance between the mandibular canal and the lingual and buccal external border does not change in any stage of the atrophic process, i.e. it remains conspicuously constant. However, the distance between the mandibular canal and the cranial and caudal borders of the body of the mandible partly changes to a statistically highly-significant extent, the distance between the canal and the atrophic alveolar ridge being affected more strongly than that between the canal and the base of the mandible. These changes were most clearly pronounced in the area of the first molar.
This paper presents an overview of important criteria for successful endosseous implantation. It discusses implant-specific anatomy, preoperative planning, the influence of structure and quality of the available bone on implant prognosis, and the principles of mechanical implant site preparation. The presentation also considers the vitality of adjacent bone, implant surface integrity, local bone defect augmentation, implant selection, and immediate implantation. The learning objective of this article is to enhance the knowledge of surgical and implant site preparation protocol.
Examination of various bone sections of edentulous atrophic mandibles showed that the body of the mandible loses up to 60% of its original bone substance during progressive atrophy. Most of the bone loss occurs in a relatively early stage of the atrophic process. The greatest extent of bone reduction can be observed in the area of the second premolar and the first molar. In the interforaminal region, which is situated mesial from them, resorption, in most cases, is not as progressive as in the premolar/molar area. The compact and cancellous bone substances are most often equally affected by resorption. Moreover, it could be observed that the cancellous bone substance of extremely atrophic mandibles particularly in the interforaminal region, is marked by a significant increase in density. This might be interpreted as a restructuring process to compensate for bone losses and to secure the stability of the atrophic body of the mandible.
In the mid-eighties, computerised tomography (CT) assisted three-dimensional imaging, and modelling of skull structures was introduced into preoperative diagnosis in maxillofacial surgery. This new method is already being used in the preoperative planning of corrections of post-traumatic defects and craniofacial deformities as well as in tumour surgery and implantology. The aim of the present study was to collect information on the reproducibility of a skull model milled from hardened polyurethane foam, and based on the CT data of a real skull. Thirty one measurements were carried out on the model and on the original skull, leading to the result that the model showed a mean inaccuracy of 1.5 mm. The deviations ranged between 0.0 and 3.6 mm. Generally, the model structures, however, tended to be larger than those of the original. As far as the total of all measurements is concerned, the model deviated from the original skull by 1.6%. A convincing aspect of the model, which cannot be obtained by any other method, is its plasticity and the possibility of 3-D orientation on a lifesize model. However, the study indicates that surgeons using this technique should consider the possible discrepancies between the model and the real skull when making preoperative assessments.
For preimplantologic evaluation and diagnosis, there are various mechanical methods for measuring the thickness of the soft tissue and thus indirectly measuring the osseous bed of the implant. This study evaluated the use of real-time sonography for analyzing the soft-tissue thickness of the entire edentulous maxilla in an anatomic examination of human cadaver specimens. The data obtained were compared with findings from the usual needle measurement method. The ultrasound measurement method produced realistic data in all measurement points of all sectional planes selected.