Biomedical subjects

Zvi Metzger

Publications and source records attributed to Zvi Metzger.

4 recordsLinked to original sources

PubMed2003

Periapical actinomycosis: a clinicopathologic study.

OBJECTIVE: We sought to evaluate the incidence and clinical outcome of an accidental finding of actinomycotic colonies in periapical lesions submitted for histologic examination. STUDY DESIGN: The study included all periapical biopsy specimens submitted for histologic examination between 1997 and 2000. Sections of paraffin-embedded tissues, 5 microm, were cut and stained by using hematoxylin and eosin, periodic acid-Schiff, and the Gram stain. The presence of typical branching colonies of filamentous bacteria staining positive for periodic acid-Schiff and Gram stain was indicative of Actinomyces. RESULTS: Typical actinomycotic colonies were identified in 17 of 963 (1.8%) periapical biopsy specimens. The mean patient age was 42, and males were predominant (65%). The maxilla was the most frequently involved site (65%), with equal distribution in the anterior and posterior areas. Radiographically, most cases presented as well-demarcated radiolucent lesions. Malignancy was suspected in 3 cases. Of the periapical lesions, 15 were epithelialized, and in 4 cases, a true epithelial-lined lumen was found, which was diagnosed as a radicular cyst. A residual cyst was diagnosed in 1 case, and in 1 case, an epithelial lining was not identified. Treatment included surgical curettage and a short course of antibiotic therapy. Healing was uneventful in all cases. CONCLUSIONS: Periapical actinomycosis is not common. Its outcome is favorable after surgical curettage supplemented by short-term antibiotic treatment. The relationship of periapical actinomycosis with the more serious cervicofacial actinomycosis should be evaluated.

Actinomyces↗

PubMed2002

The effect of bacterial endotoxin on the early tensile strength of healing surgical wounds.

Wound healing in the oral cavity occurs in a bacteria-rich environment, which may affect its outcome. Furthermore, it takes place where forces are frequently applied to the healing tissue. The effect of bacterial endotoxin on the development of tensile strength in healing wounds was studied using surgical skin wounds in rats as a model. Collagen membranes soaked with 0.01 microg of bacterial endotoxin were inserted into surgical skin wounds, and their effect was studied on days 6 and 10. Membranes with no endotoxin served as controls. Endotoxin inhibited the early development of tensile strength in 6 days, healing wounds by 38%, whereas the collagen membrane alone had no effect. Dexamethasone (0.5 mg/kg every 72 h) had a suppressive effect on the development of tensile strength in healing noncontaminated wounds, but not in those containing bacterial endotoxin. These results suggest that bacterial endotoxin may interfere with the early healing of wounds. Understanding the mechanisms of this inhibition may result in treatments that will allow this response to be faster and more reproducible.

Analysis of Variance↗

PubMed2002

Case selection for apical surgery: a retrospective evaluation of associated factors and rational.

Endodontic failures associated with poor quality of endodontics respond favorably to retreatment. Nevertheless, under certain clinical conditions, apicoectomy should be the preferred procedure. A retrospective survey of 200 roots that were referred for apical surgery revealed that 83% of the roots were inadequately obturated, including 8.5% with no root canal filling at all. In 49 of the roots in this group (24.5% of the referred cases) nonsurgical retreatment was judged by an endodontist as either impossible or improbable because it might jeopardize the root integrity. Retreatment should have been the preferred treatment modality for the rest of the group, provided that coronal restorations could be safely bypassed or removed. Posts were found in 63 of these teeth, however 35 of them were either short or loosely fitting and could safely be removed. The rest of the posts were longer than 5 mm, which might have presented a problem if their removal was attempted. In 45% of the 200 cases in the present study, surgical intervention was justified. The rest of the cases (55%) should have either been subjected to a follow-up (10.5%) or retreated nonsurgically by a skilled endodontist (44.5%). These results indicate that referring dentists may not appreciate the retreatment possibilities offered by modern endodontics, and they emphasize the need for a shift of concept: endodontists should be involved in the decision making before referring a patient to surgery.

Apicoectomy↗

PubMed2002

Periapical lesion development in rats inhibited by dexamethasone.

Bone resorption is one of the hallmarks of inflammatory periapical lesions and is mediated by cytokines. Recent insights into the immunobiology of these lesions indicate that pharmacological modulation of their bone resorbing activity may be possible. Periapical lesions were induced in rats by occlusal exposure of the pulps of their lower first molars. The size of the resulting lesions was followed-up and evaluated by image analysis of their radiographs. The lesions increased with time, and the average area of their radiographic images reached 2.18 (+/- 0.33) mm2 by day 21. Systemic dexamethasone treatment (0.5 mg/kg, every third day) inhibited the growth of the periapical lesions, which reached an average area of 1.63 (+/- 0.30) (p < 0.01). These results support the hypothesis that bone resorption in periapical inflammatory lesions may be pharmacologically down regulated.

Animals↗