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Biomedical subjects

A Mombelli

Publications and source records attributed to A Mombelli.

At least 55 records · Page 3Linked to original sources
PubMed1996

Microbiological monitoring.

If periodontal disease is due to a limited number of bacterial species, then continuous maximal plaque suppression is not the only possibility for prevention and therapy. Specific elimination or reduction of pathogenic bacteria from plaque becomes a valid alternative. Recent studies indicate that the elimination of certain putative pathogens is particularly difficult. New diagnostic methods should allow the choice of better suited procedures, make chosen procedures more effective (through better timing, dosage, selection of devices or drugs, increase of specificity, etc.) or lead to the elimination of unnecessary work (e.g., the treatment of non-susceptible sites or patients). The benefit of newly proposed tests depends on the possible impact of the obtained information on clinical decisions and on the consequences these decisions have for treatment. Thus, diagnostic methods and therapeutical options have to be evaluated together.

Anti-Bacterial Agents↗
PubMed1995

The microbiota of osseointegrated implants in patients with a history of periodontal disease.

The purpose of this study was to determine the presence of suspected periodontal pathogens in the peri-implant microflora of osseointegrated implants exposed 3 and 6 months to the oral environment of patients previously treated for periodontal disease. Subgingival microbial samples were taken in the deepest residual pocket of each quadrant in 10 patients before placement of ITI implants and in 10 patients before abutment connection of Brånemark implants. The samples were cultured using continuous anaerobic techniques. 4 patients were positive for P. gingivalis, 13 for P. intermedia, 2 for A. actinomycetemcomitans, 16 for Fusobacterium, 7 for C. rectus and 12 showed microscopic evidence of spirochetes. After 3 and 6 months exposure of the implants to the oral environment, one sample was obtained from the peri-implant sulcus in each patient. P. gingivalis was found in 2 patients in the peri-implant samples after 3 and 6 months. 6 peri-implant samples were positive for P. intermedia after 3 months, 7 after 6 months. Fusobacterium was present in 13 peri-implant samples after 3, and in 12 samples after 6 months. 4 patients showed evidence of for C. rectus after 3 months, 2 after 6 months. Spirochetes were seen in 3 peri-implant samples after 3 and in 5 after 6 months. None of the implants were found to be colonized by A. actinomycetemcomitans, although the organism was detected on teeth in 1 individual. Similar distribution patterns were noted for ITI and Brånemark type implants.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Correlation of the periodontal status 6 years after puberty with clinical and microbiological conditions during puberty.

The purpose of this study was to assess the oral clinical and microbiological status of young adults 6 years after puberty and to compare these findings with the conditions observed during puberty. Clinical and microbiological parameters were monitored in 42 individuals 10 x between the ages of 11 and 14 years. 33 individuals were re-examined 10 years after the start of this monitoring. Microbiology included 2 subgingival samples per subject taken from the mesiobuccal aspects of the upper 1st molars. The samples were subject to continuous anaerobic culturing. Individuals with a marked and sustained increase in mean papillary bleeding scores during puberty (group A, n = 16) differed 6 years later from individuals without pronounced puberty gingivitis (group C, n = 8) in several aspects. Individuals in group A had a significantly higher gingival bleeding tendency and an increased number of sites with more than 3 mm attachment loss. The subjects in group C showed the lowest anaerobic total cultivable counts. Spirochetes were detected only in group A subjects (4 samples in 3 individuals). In all positive sites, spirochetes had been identified at least 8 out of 10 times during puberty. A. actinomycetemcomitans was present in only one individual of group A. P. gingivalis had not been detected during puberty; none of the samples were P. gingivalis positive 6 years later. P. intermedia was found in 27% of all samples, isolates belonging to the P. melaninogenica group of black pigmenting anaerobes had a frequency of 6%, 6 years after puberty.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Clinical and microbiological changes associated with an altered subgingival environment induced by periodontal pocket reduction.

The purpose of the present investigation was to study the effect of an altered subgingival environment, induced by changing the local soft tissue morphology, i.e., pocket depth reduction, on the subgingival microbiota and the clinical conditions. 7 patients aged 30-60 years with generalized marginal periodontitis were selected. Patients were instructed in proper oral hygiene and all teeth were cleaned supragingivally. Mucoperiosteal flaps were raised and the bone re-contoured to eliminate angular bony defects. While the control teeth were carefully debrided and thoroughly root planed, no root instrumentation was performed on the test teeth. Calculus deposits visible to the naked eye were only chipped-off with the tip of a scaler. The flaps were apically repositioned and sutured at the level of the bone crest. Clinical parameters showed a similar pattern of response in the test and control sites over a one year observation period post therapy. Probing depths and probing attachment levels were significantly reduced one month after surgery and remained at a lower level. A significant decrease was also noted for total anaerobic viable bacterial counts. The proportion of the Gram-negative anaerobic rods decreased significantly in both groups. P. gingivalis, Fusobacterium sp., C rectus were detected significantly less often after treatment in both groups. Capnocytophaga and A. odontolyticus, on the other hand, were more frequently isolated after therapy. These findings corroborate the concept that the reduction of selected subgingival microorganisms is the key element for the success of periodontal therapy, rather than the removal of tooth substance and mineralized deposits by root instrumentation.

Actinomyces↗
PubMed1995

Maintenance of new attachment 1 and 4 years following guided tissue regeneration (GTR).

The aim of the present study was to evaluate periodontal tissue alterations during the maintenance phase following GTR therapy. 18 patients (average age 54 years, range 39-79 years) with 19 local periodontal defects were monitored longitudinally using clinical periodontal parameters and radiographic assessments of bone level changes. 6 out of originally 24 patients were not available at the 4-year examination (2 patients were unwilling to participate and in 4 patients root amputations or tooth extractions had to be performed). Evaluations were performed at baseline, 3 months, 1 year and 4 years following GTR therapy (using non-resorbable Gore-Tex Periodontal Material). The changes observed at the deepest site of each tooth treated by GTR were compared to those encountered in the entire dentition. Supportive periodontal therapy was performed according to the patient's individual needs between 3 and 12 times between the 1 and 4 years examination. The plaque index and the gingival index at the 4 years examination were assessed and had increased to almost double the value of baseline, although the BOP remained lower compared to baseline data. Between the 1 and 4 years examinations, 1.27 mm of clinical attachment was lost as a mean. Regarding the site of each tooth treated with GTR with the initially deepest probing pocket depth, 1.42 mm of clinical attachment was lost during the maintenance phase. However, compared to baseline data, 1.37 mm of new attachment could be maintained. The clinical attachment level was maintained within +/- 1 mm in 12 out of 19 sites during the 4 years of maintenance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

The effect of plaque control in subjects with shallow pockets and high prevalence of periodontal pathogens.

In a previous study, it was shown that professional tooth cleaning 3x a week had a significant influence on the subgingival microbiota of shallow pockets. The purpose of this investigation was to study the effect of a single episode of full-mouth supragingival cleaning and oral hygiene instructions in subjects with minimal periodontal disease but high prevalence of putative periodontal pathogens. 10 subjects from Arabic countries, aged between 22 and 48 years, which had previously not been exposed to any dental care other than extractions and fillings, were selected for this trial. DNA probe analysis of subgingival samples, taken in the deepest pocket of each quadrant, showed presence of Porphyromonas gingivalis and Prevotella intermedia in all patients, and presence of Actinobacillus actinomycetemcomitans in 5 individuals. 85% of all samples were P. gingivalis-positive, 83% were positive for P. intermedia and 43% were A. actinomycetemcomitans-positive. 4 weeks after treatment, subgingival microbiological samples were again taken in the same sites. In 8 patients, P. gingivalis could still be detected after treatment. However, the number of P. gingivalis positive samples was reduced from 85% to 38%, and the bacterial counts in positive samples were markedly lower than at baseline. P. intermedia-positive samples were obtained from 7 patients after treatment. 33% of all samples were still positive, but showed markedly reduced bacterial counts. 4 patients still yielded A. actinomycetem comitans-positive samples after treatment. Here, the number of positive samples was reduced to 15%, and the bacterial counts were barely exceeding the detection limit.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Experimentally induced peri-implant mucositis. A clinical study in humans.

The purpose of this study was to compare the clinical and microbiological (microscopic) parameters during the development of experimental gingivitis and experimental peri-implant mucositis. Twenty partially edentulous patients were treated for moderate to advanced periodontal disease. Following active periodontal therapy consisting of motivation, instruction in oral hygiene practices, scaling and root planing and periodontal surgery where indicated, IMZ oral implants were incorporated in posterior edentulous areas. After 3 months of healing, the prosthetic abutments were connected, and the patients were closely supervised for another 2 months of healing. At this time, baseline data were obtained. Re-examinations were scheduled at 3 and 6 months. Following this, the patients were asked to refrain from oral hygiene practices for 3 weeks. At all examinations including the end of the period of no oral hygiene, the following clinical parameters were obtained: Plaque Index, Gingival Index and Sulcus Bleeding Index, all modified by Mombelli et al. (1987), probing pocket depths and recession in mm. Furthermore, submucosal/subgingival plaque samples were obtained and analyzed using phase contrast microscopy. At the end of the 3-week period of plaque accumulation, optimal oral hygiene was reinstituted. There were no statistically significant differences between the mean values of all parameters at implant compared to tooth sites at any observation periods. The period of no oral hygiene demonstrated a similar cause-effect relationship between the accumulation of bacterial plaque and the development of peri-implant mucositis as established for the gingival units by the experimental gingivitis model.

Adult↗
PubMed1994

Actinobacillus actinomycetemcomitans in adult periodontitis. I. Topographic distribution before and after treatment.

The aim of this investigation was to study the topographic distribution of Actinobacillus actinomycetemcomitans in patients with adult periodontitis before and after mechanical periodontal treatment (repeated oral hygiene instructions, systematic deep scaling, and root planing). In 10 A. actinomycetemcomitans-positive patients, subgingival microbial samples were obtained from the mesial and distal aspect of every tooth (38 to 56 sites per patient, 479 sites in total) before and one month after treatment. The samples were cultured on TSBV agar. A. actinomycetemcomitans was identified based on phenotypical and serological criteria. A. actinomycetemcomitans was present in 40% of the samples taken before and in 23% of the samples taken after treatment. Before treatment, the frequency of A. actinomycetemcomitans-positive samples per patient was wide spread and ranged from 7 to 90%. After treatment, two patterns of A. actinomycetemcomitans distribution could be recognized: the majority of the patients showed only a limited percentage of positive samples and yielded less than 10(5) A. actinomycetemcomitans. In three subjects, however, relatively high numbers of positive sites were still present, and many of these positive sites showed high A. actinomycetemcomitans counts. Logistic multiple regression showed the presence of A. actinomycetemcomitans before treatment depended strongly on the individual and was significantly associated with probing depth (P < 0.001) and bleeding upon sampling (P = 0.07). The highest chance of detecting A. actinomycetemcomitans existed in deep pockets which bled upon sampling. After treatment, there was a strong individual influence and an influence of probing depth (P < 0.001). The highest chance of detecting A. actinomycetemcomitans existed in residual pockets in the range of 5 mm.

Adult↗
PubMed1994

Actinobacillus actinomycetemcomitans in adult periodontitis. II. Characterization of isolated strains and effect of mechanical periodontal treatment.

Ten systemically healthy subjects (ages 28 to 60 years) with untreated moderate to severe periodontal disease and evidence of presence of A. actinomycetemcomitans underwent standard mechanical periodontal treatment consisting of oral hygiene instruction and systematic deep scaling and root planing. Before, and 4 to 5 weeks after treatment, clinical measurements and separate subgingival microbiological samples were taken from the mesial and distal aspect of every tooth, with the exception of the third molars. A. actinomycetemcomitans could still be detected in all patients after treatment. In 9 of the 10 patients, all tested isolates from both examinations were of a single type. Two patients carried serotype a; 2 serotype b; 2 serotype c; and 1 serotype e. Two individuals showed only non-typeable isolates lacking serotype a, b, c, d, or e specific antigens. Another subject was colonized by serotype c and, in addition, yielded a non-typeable isolate. Persistence of A. actinomycetemcomitans after treatment was significantly correlated with the frequency of A. actinomycetemcomitans before treatment (P < 0.001) and the mean probing depth before treatment (P < 0.05). No serotype-specific patterns of treatment outcome could be recognized. The analysis of the site specific effect of treatment showed a significant relationship between post treatment levels of A. actinomycetemcomitans and both probing depth reduction as well as attachment gain. Individuals showing evidence of A. actinomycetemcomitans in a multitude of sites appeared to be more difficult to treat than patients with few positive sites only. Within such individuals, the deeper pockets showed the greater resistance to eradication of A. actinomycetemcomitans.

Adult↗
PubMed1993

Seroclassification of hitherto nontypeable Actinobacillus actinomycetemcomitans strains: evidence for a new serotype e.

Serotyping of 89 Actinobacillus actinomycetemcomitans isolates by indirect immunofluorescence with serotype-specific monoclonal antibodies yielded 10 nontypeable strains. The aim of the present study was to re-evaluate the seroclassification of these strains with a different assay. Electroblotted antigens of nontypeable isolates and selected reference strains were immunostained with 37 human sera containing high antibody titers to A. actinomycetemcomitans. Such immunoblots typically showed an immunodominant, serotype-specific antigen smear. Twelve human sera were found to recognize specifically serotype a, 10 serotype b and 9 serotype c. Three sera contained antibodies to 2 or all 3 serotype antigens; 3 sera had no activity to any reference strain smear antigen. There was complete agreement between the seroclassification of the reference strains with the monoclonal and the polyclonal reagents. Seven of the 10 strains, nontypeable with monoclonal antibodies, could also not be typed by the human sera. Of the remaining 3 strains, one belonged to a previously unrecognized serovar of serotype a, and 2 isolates expressed a novel smear antigen detected by the 3 human sera containing no antibodies to the serotype a, b, or c antigens. We propose that these 2 strains be assigned to a new A. actinomycetemcomitans serotype, designated serotype e.

Aggregatibacter actinomycetemcomitans↗
PubMed1993

Microbiology of the dental implant.

Longitudinal studies have shown that successful implants are colonized by a predominantly Gram-positive, facultative flora, which is established shortly after implantation. Repeated microbiological sampling in patients with clinically stable implants showed no significant shifts in the composition of this flora over five years. In patients with bone loss and pocket formation around implants, however, a significantly different flora was found: Gram-negative anaerobic bacteria, particularly fusobacteria, spirochetes, and black-pigmenting organisms such as Prevotella intermedia were often present in high proportions. Antimicrobial treatment with agents specifically active against anaerobes could halt progression of peri-implant infections in such cases. Although there may be non-microbial primary causes for implant failure, these studies show that Gram-negative anaerobes may play a rôle in peri-implant infections, and that their elimination leads to improvement of the clinical condition.

Animals↗
PubMed1993

Isolation of periodontal species after guided tissue regeneration.

One advanced localized periodontal lesion in each of 10 patients was treated using the guided tissue regeneration procedure. Six weeks after placement of expanded polytetrafluoroethylene (ePTFE) membranes, microbial samples were taken from each treated site and the membranes were removed. Six weeks later the cases were re-evaluated. They had all healed successfully with varying amounts of gain of clinical attachment. Gram-negative, anaerobic rods were found in all samples and made up 31% of all organisms cultivated. In 1 patient, Porphyromonas gingivalis was found in a proportion of 17.5%. Six of the other 9 patients harbored Prevotella intermedia (mean proportion 21.3%) and 6 Prevotella melaninogenica (6.8%). Fusobacterium and Capnocytophaga were also frequently found. The results demonstrate that ePTFE membranes are frequently colonized by periodontal microorganisms. The importance of bacterial colonization on clinical success is presently not known. Further studies are needed to determine the effect of the presence or absence of putative pathogens during guided tissue regeneration.

Actinomyces↗