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Biomedical subjects

L Sbordone

Publications and source records attributed to L Sbordone.

At least 37 records · Page 2Linked to original sources
PubMed1990

Recolonization of the subgingival microflora after scaling and root planing in human periodontitis.

The purpose of this study was to evaluate the recolonization patterns of the subgingival microflora of adult periodontitis patients after a single session of scaling and root planing. In each of eight patients, three clinically diseased sites were investigated microbiologically by darkfield microscopy and cultural analysis. After initial clinical and microbiological parameters were determined, each subject received a single session of scaling and root planing but no oral hygiene instructions. Clinical indices were measured and microbial parameters were reassessed 7, 21, and 60 days after treatment in a manner such that each of the test sites was sampled only once after treatment. Recolonization was evaluated by matching any single site with its own preoperative site. A significant improvement in probing depth was noted for up to 60 days after treatment, while the gingival index did not change markedly during the course of the study. The microbial composition of treated sites 7 days after scaling and root planing, as determined by both cultural and darkfield data, was similar to that of periodontally healthy sites. Differences between cultural and darkfield data became apparent at the 21 day sampling point. The darkfield data showed that the sites consisted of cocci with few spirochetes. Cultural data demonstrated that the majority of the cocci were anaerobic, namely Streptococcus intermedius, Veillonella parvula, and Peptostreptococcus micros. At 60 days, there was no significant variation in any of the parameters from pretreatment levels. The most prevalent anaerobic rods prior to and 60 days after therapy were Fusobacterium nucleatum, Bacteroides gingivalis, and B. intermedius.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinobacillus↗
PubMed1990

Generalized juvenile periodontitis: report of a familial case followed for 5 years.

The case of a family, followed for 5 years and showing an exceptionally high prevalence of Generalized Juvenile Periodontitis (GJP), is presented. Two siblings were affected by a severe form of GJP meanwhile the dycorial twin of one was periodontally healthy. Both the affected siblings showed infection by Actinobacillus actinomycetemcomitans (Aa), but only one presented a reduced chemotaxis of the peripheral PMNs. The dycorial twin consistently displayed a freedom from Aa and a reduction in the peripheral PMNs chemotaxis. The extraction of the compromised teeth in the two affected siblings has been followed by colonization of new sites by Aa; only repeated administration of systemic tetracyclines seems to protect the subjects from colonization of other sites. These findings may contribute to the understanding of the etiology, pathogenesis, and therapy of juvenile periodontitis.

Actinobacillus↗
PubMed1990

[Bacterial recolonization in the guided regeneration of the inter-radicular periodontal tissues].

The present experimental study has been undertaken in order to analyse clinically and microbiologically the formation of new periodontal attachment in class II furcation lesions in mandibular molars, comparing healing after surgical conventional therapy and after guided periodontal tissue regeneration technique using non-resorbable membranes and evaluating at the same time, with cultural anaerobic technique, the influence on healing of the bacterial recolonization of some periodontally pathogenic species. Clinical results have demonstrated that, after therapy, may occur a certain discrepancy between soft and hard tissue regeneration and that the bone tissue shows a different pattern of apposition in the horizontal and vertical direction. Microbiological data have underlined the significance of surgical instrumentation in the guided inter-radicular periodontal tissue regeneration and have confirmed the necessity of maintaining the healing sites free from the main periodontal pathogens.

Adult↗
PubMed1989

[In vitro antibiotic sensitivity of several species of oral spirochetes].

Results of a series of "in vitro" antibiotic susceptibility tests on some strains of oral Treponema are presented. Different antimicrobial agents have shown different results and only tetracycline and erythromycin have shown consistent antibacterial properties. Surprisingly penicillin has allowed a latent "in vitro" growth of the tested Treponema. The Authors conclude that, according to the data presented, a revision of the current criteria of the antimicrobial therapy for the oral infections associated with the presence of species of Treponema is needed.

Anti-Bacterial Agents↗
PubMed1986

Marginal tissue reactions at osseointegrated titanium fixtures (I). A 3-year longitudinal prospective study.

16 consecutive totally edentulous patients were provided with 95 osseointegrated titanium fixtures in 7 upper and 9 lower jaws. Facultatively removable bridges were later connected to abutments, attached to the fixtures. The marginal soft and hard tissue reactions were investigated at a baseline examination and after 6, 12, 21, 30 and 39 months by standardized clinical and radiographical methods. At the last examination, microbiological samples and gingival biopsies were also analysed. The % ratios of abutments without plaque, 70-75%, and without any gingivitis, 80-85%, were almost constant throughout the study. The mean probing depth was 2.9 mm at the final examination. About 75% of all probing depths were 3 mm or less and none exceeded 5 mm. The bridge-gingiva distances increased during the investigation. Attached gingiva surrounded 65% of the buccal and lingual abutment surfaces. Only 0.9 mm marginal bone was lost as a mean during the first year and not more than 0.05 mm annually for the next 2 years. After 6 months, no significant changes in marginal bone levels occurred. The perifixtural bone gradually became more radiopaque, especially marginally in upper jaws, indicating a successive load-related remodelling. The microbiotia comprised coccoid cells and non-motile rods to 93% in 32 samples. Healthy tissues were present in 35% of the 14 soft tissue biopsies. In a further 29%, only a slight inflammation was observed. No constant correlations could be established for any of the investigation parameters used. It is concluded that the marginal soft tissue reactions were mild and not significant for a progressive periodontitis. Mobility tests of separate fixtures combined with quantitative and qualitative standardized radiological examinations of the surrounding bone appear to provide a truer comprehension of longitudinal events at osseointegrated implants than conventional clinical soft tissue observations. The prognosis for the osseointegrated implants appears excellent, especially with regard to the microbiotia, the small marginal bone height changes, and the radiological indications of remodelling in the perifixtural bone.

Adult↗
PubMed1986

The predominant cultivable microbial population of adult periodontitis.

An extensive characterization of the cultivable microbial population, present in gingival pockets of a selected group of eight patients with periodontal disease, has been performed. The result obtained, from samples collected from six different periodontal sites in each patient, indicate a great prevalence of anaerobic bacteria. It is likely that the presence inside the gingival pockets of anaerobic cocci, to which the rods are capable of a selective coaggregation mechanism, creates conditions favorable to the proliferation of the latter type of bacteria. These findings suggest that the evolution of adult periodontitis is based on a chronic inflammatory stimulus and the necrosis of gingival epithelium caused by the proliferation of the anaerobic rods.

Adult↗
PubMed1985

Marginal tissue reactions at osseointegrated titanium fixtures.

A longitudinal prospective and a cross-sectional retrospective study were undertaken in order to investigate the marginal tissue reactions at osseointegrated titanium fixtures and their abutments, supporting fixed bridges. Conventional clinical periodontal examination methods were combined with a serial-identical radiography. At the termination of the studies samples were taken for microbiological and histological analyses. Altogether the reactions at 220 fixtures in 40 jaws were explored. The clinical parameters were not found correlated with the other examination methods. Only 0.9 mm marginal bone was lost as a mean during the first year and then not more than 0.05-0.07 mm as a mean annually for the follow-up years. A stress-related remodelling of the perifixtural bone was observed radiographically. The microbiotia in the gingival pockets was dominated by cocci and non-motile rods (94%), indicating a favourable composition if similar findings had been observed at teeth. Half the number of the biopsies had no inflammatory infiltrates and a further third had the lowest inflammatory score in a 3-grade scale. The results indicate that the soft tissue surrounding the gingival part of osseointegrated fixtures remains remarkably healthy, which, in combination with the annual minor loss of marginal bone, is an indication of good long-term clinical prognosis.

Alveolar Process↗
PubMed1983

Biologic evaluation of a silver-copper-germanium dental casting alloy and a gold-germanium coating alloy.

An Ag-Cu-Ge alloy and an Au-Ge alloy were evaluated for their hemolytic effect on rabbit blood, cytotoxicity to alpha-L fibrosarcoma cells, and allergenic effect on guinea pigs. Neither alloy evoked a significant hemolytic response; cytotoxicity, and that of pure germanium, was no greater than that of ZOE cement; and, on the basis of the guinea pig response, the potential human allergenic response was considered to be Grade I (weak) and Grade II (mild), respectively.

Animals↗
PubMed1980

Metabolism by rat hepatic microsomes of fluorinated ether anesthetics following isoniazid administration.

The possibility that enflurane defluorination is increased following treatment with isoniazid was investigated in male Fischer 344 rats. The effects of various isoniazid dosage regimens on the hepatic microsomal defluorination rates of enflurane were compared with those of several other ether anesthetics, and the conditions for production of maximal enflurane defluorination rates were determined. Seven to ten days of treatment with 50 mg/kg/day isoniazid (Nydrazid) resulted in maximal rates of defluorination of methoxyflurane, enflurane, isoflurane, and sevoflurane with no overt sign of toxicity. Compared with saline treatment of control rats, isoniazid increased defluorination of enflurane 370 per cent, methoxyflurane 259 per cent, sevoflurane 283 per cent, and isoflurane 168 per cent. Previous studies have shown that while the enzyme inducer phenobarbital increased in vitro rates of methoxyflurane defluorination approximately 1000 per cent, the rate of enflurane defluorination remained unchanged or increased by 100 per cent at most. In this study, enhanced hepatic microsomal defluorination was not associated with an increase in cytochrome P-450 per mg protein. Anesthetic defluorination rates were not altered by treatment with chlorobutanol, the preservative contained in Nydrazid.

Animals↗