Biomedical subjects

W J Loesche

Publications and source records attributed to W J Loesche.

At least 19 recordsLinked to original sources

PubMed1992

Metronidazole in periodontitis: reduced need for surgery.

A considerable amount of circumstantial evidence indicates that most forms of periodontitis are due to the presence or dominance of a finite number of bacterial species in the subgingival plaque. Almost all of the putative pathogens are anaerobic species, indicating that most forms of periodontitis could be diagnosed as anaerobic infections. In this double-blind investigation, patients with elevated proportions or levels of spirochetes in 2 or more plaque samples, i.e., 60% spirochetes, were randomly assigned to receive either metronidazole, 250 mg 3 x a day for 1 week, or placebo (positive-control) after the completion of all debridement procedures. When the patients were re-examined 4 to 6 weeks later, the patients in the metronidazole group (n = 15) exhibited a highly significant (p less than 0.01) reduction in probing depth and apparent gain in attachment levels relative to the patients (n = 18) in the positive-control group about those teeth that initially had probing depths of 4 to 6 mm. This pattern was also observed about teeth that initially had probing depths greater than or equal to 7 mm. This reduction in probing depths and apparent gain in attachment was associated with a significant reduction in the need for periodontal surgery in the metronidazole-treated patients (difference 8.4 teeth per patient) compared to the positive-control patients (2.6 teeth per patient). These clinical improvements in the metronidazole group were associated with significantly lower proportions of spirochetes, selenomonads, motile rods, and P. intermedius, and a significantly higher proportion of cocci in the plaques. These findings indicate that systemic metronidazole, when given after all the root surface debridement is completed, leads to additional treatment benefits, including a reduced need for surgery, beyond that which can be achieved by debridement alone.

Adult↗

PubMed1992

Relationship of microbial and salivary parameters with dental caries in Brazilian pre-school children.

Caries examination and collection of paraffin wax-stimulated saliva samples were performed in 37 children, 3-6 years old, in a child-care facility at the Vidigal slum, Rio de Janeiro, Brazil. The levels of mutans streptococci and lactobacilli in saliva were estimated by the Cariescreen and by the Dentocult tests and the saliva secretion rate was determined. Statistical analysis was performed on surface-based and patient-based caries prevalence rates (SBCPR and PBCPR), and related to bacterial and salivary parameters. The results show that 31 of the 37 children were caries active. The SBCPR for the primary dentition was 6.7% +/- 1.0%. Occlusal surfaces were the most affected by decay. Regression analysis revealed that mutans streptococci salivary levels were significantly associated with the SBCPR (P = 0.0001). Similarly, lactobacilli salivary levels were significantly associated with the SBCPR (P = 0.0001). No significant association could be found between the saliva secretion rate and the SBCPR. When regression analysis was used to model dependence of the SBCPR on both organisms, the mutans streptococci and lactobacilli salivary levels were significantly associated with the SBCPRs (P = 0.0021 and 0.0118, respectively), and salivary levels of these organisms accounted for 57% of the SBCPR variability. These findings indicate that the levels of mutans streptococci and lactobacilli in saliva are significantly related to the SBCPRs on the primary dentition of these children.

Analysis of Variance↗

PubMed1992

Comparison of various detection methods for periodontopathic bacteria: can culture be considered the primary reference standard?

The development of diagnostic tests for a periodontal infection raises the issue as to what the appropriate reference standard, or "gold standard," should be for the evaluation of a new test. The present research was initiated to compare the ability of several detection methods, i.e., a serial dilution anaerobic culture and/or microscopic procedure, a DNA probe procedure, and immunological reagents using both an enzyme-linked immunosorbent assay and an indirect immunofluorescence assay to detect Treponema denticola, Porphyromonas gingivalis, Bacteroides forsythus, and Actinobacillus actinomycetemcomitans in subgingival plaque samples taken from 204 periodontally diseased tooth sites. The prevalence of the four monitored species varied as a function of both the species and the detection method. Spirochetes were present in 99% of the plaques, whereas A. actinomycetemcomitans was detected at the lowest frequency. The culture method yielded the lowest prevalence values for the three cultivable species. This raised the question as to which results, those obtained by culture or those obtained by the DNA probes and the immunological reagents, were the most reliable. This issue was addressed by looking at the prevalence profile of the monitored organisms, as determined by all the detection methods. If the species was detected by three or four of the detection methods, then it was considered present, whereas if it was absent by three or four of the detection methods, then it was considered absent. This approach showed the DNA probes and immunological reagents to be significantly superior (P less than 0.05) to the culture approach for the detection of P. gingivalis, A. actinomycetemcomitans, and B. forsythus and to be comparable to the microscopic approach in the detection of T. denticola.

Aggregatibacter actinomycetemcomitans↗

PubMed1992

Comparison of the benzoyl-DL-arginine-naphthylamide (BANA) test, DNA probes, and immunological reagents for ability to detect anaerobic periodontal infections due to Porphyromonas gingivalis, Treponema denticola, and Bacteroides forsythus.

Most forms of periodontal disease are associated with the presence or overgrowth of anaerobic species that could include Treponema denticola, Porphyromonas gingivalis, and Bacteroides forsythus among others. These three organisms are among the few cultivable plaque species that can hydrolyze the synthetic trypsin substrate benzoyl-DL-arginine-naphthylamide (BANA). In turn, BANA hydrolysis by the plaque can be associated with periodontal morbidity and with the presence of these three BANA-positive organisms in the plaque. In this investigation, the results of the BANA test, which simultaneously detects one or more of these organisms, were compared with the detection of these organisms by (i) highly specific antibodies to P. gingivalis, T. denticola, and B. forsythus; (ii) whole genomic DNA probes to P. gingivalis and T. denticola; and (iii) culturing or microscopic procedures. The BANA test, the DNA probes, and an enzyme-linked immunosorbent assay or an indirect immunofluorescence assay procedure exhibited high sensitivities, i.e., 90 ot 96%, and high accuracies, i.e., 83 to 92%, in their ability to detect combinations of these organisms in over 200 subgingival plaque samples taken from the most periodontally diseased sites in 67 patients. This indicated that if P. gingivalis, T. denticola, and B. forsythus are appropriate marker organisms for an anaerobic periodontal infection, then the three detection methods are equally accurate in their ability to diagnose this infection. The same statement could not be made for the culturing approach, where accuracies of 50 to 62% were observed.

Bacteria, Anaerobic↗

PubMed1992

DNA probe and enzyme analysis in periodontal diagnostics.

Recent research in periodontology has indicated that a finite number of bacterial species are associated with periodontal disease. This has generated the hypothesis that periodontal disease is essentially an infection due to one or more of the putative periodontopathogens; i.e., the specific plaque hypothesis (SPH). This microbial specificity paradigm has already changed the way researchers and some clinicians view periodontal disease. The clinician must heed several cautions signs, however, if he is to use the SPH to provide treatment options that could enhance the delivery of care. There are several diagnostic technologies that can be used to detect and semi-quantitate those bacterial species that have been identified as periodontopathogens. This paper discusses diagnostic tests based upon the detection in plaque of DNA segments or enzyme activity(ies) that are unique for one or more of the suspected periodontopathogens.

Aggregatibacter actinomycetemcomitans↗

PubMed1992

The specific plaque hypothesis and the antimicrobial treatment of periodontal disease.

According to the specific plaque hypothesis a measurable amount of periodontal disease is due to the overgrowth of specific bacterial types. The author advocates the theory and discusses treatment. This includes techniques for diagnosing the predominant bacterial types, antibiotic therapy and the relevance of regular debridement.

Bacteria, Anaerobic↗

PubMed1991

Role of anaerobic bacteria in periodontal disease.

Microscopic examination and cultural studies of subgingival dental plaque have indicated that a complex, predominantly anaerobic flora is associated with periodontal disease. About 10 to 15 bacterial species, all of them anaerobic with the exception of A actinomycetemcomitans, have been suggested to be periodontal pathogens. These data indicate that most forms of periodontal disease are chronic anaerobic infections. This possibility has been evaluated by the systemic use of metronidazole, an antimicrobial whose spectrum of activity is limited to anaerobes. These six metronidazole double-blind studies demonstrate that metronidazole, given for periods of time as short as 1 week, can lead to a significant improvement in periodontal health. Maximal benefits are obtained when the metronidazole is given after the tooth surfaces are debrided of plaque and calculus. The best response is often noted in the more advanced cases, in which an anaerobic flora including spirochetes and black-pigmented Bacteroides usually predominates in the subgingival plaque. The success of short-term metronidazole treatment in these investigations indicates that the overgrowth of certain anaerobes in the plaque is responsible for most forms of periodontal disease.

Bacteria, Anaerobic↗

PubMed1991

Detection of two anaerobic periodontopathogens in children by means of the BANA and ELISA assays.

The mouths of young children become colonized by a variety of bacteria, but there have been only a few studies that have sought the presence of periodontopathic species in this population. Almost all of these studies used culturing techniques rather than the newer detection methodologies for various periodontopathogens. Studies in adults have shown that Treponema denticola and Porphyromonas (Bacteroides) gingivalis can be detected in dental plaque by use of the BANA and ELISA diagnostic tests. In the present study, plaque samples from four subgingival sites in each of 157 children (aged from two to 18 years) were tested for BANA hydrolysis with a BANA reagent card, and for T. denticola and P. gingivalis with an ELISA assay. Anaerobic periodontopathogens hydrolyzing the BANA substrate were found to be present in at least one of four plaque samples in 88 children (56%). T. denticola and/or P. gingivalis were detected by ELISA in at least one plaque sample in each of 135 children (86%). This study shows that children are widely colonized by these micro-organisms. A higher proportion of Black children than Caucasian children was colonized by these BANA-positive organisms. Also, children having a parent with a documented history of periodontal disease were more likely to be BANA-positive than were children of parents with unknown periodontal status.

Adolescent↗

PubMed1991

Effects of metronidazole on periodontal treatment needs.

Periodontitis, a common cause of tooth loss in adult populations, is an inflammatory response to the overgrowth of anaerobic organisms such as spirochetes and bacteroides and, in some cases, micro-aerophilic organisms in the subgingival plaque. In the present investigation, using a double-blind clinical design, we sought to determine whether 1 week of metronidazole treatment plus debridement of the tooth surfaces was superior to 1 week of placebo treatment plus debridement (positive control) in reducing the subsequent amount of periodontal surgery given to the patients. Thirty-nine patients were randomly assigned to either the metronidazole or placebo (positive control) groups. All patients were given the necessary scaling and root planing and were unsupervised in their usage of the medication. After the completion of this treatment, they were reexamined and it was found that the metronidazole regimen caused a significant reduction in surgical needs of about 5 teeth per patient compared to the positive control (difference before and after treatment 8.3 +/- 6.8 teeth metronidazole versus 2.9 +/- 4.8 positive control, P = 0.007). The difference between groups was maintained during the 2 to 3 years' recall period. Metronidazole had a significant effect on the site specific reduction of spirochetes: 90% of the sites in the metronidazole group versus 64% in the positive-control group had a decrease in the percentage of spirochetes (P less than 0.05). We conclude that systemic metronidazole given 250 mg tid for 7 days in conjunction with debridement of the tooth surfaces can significantly reduce the need for periodontal surgery compared to the standard regimen which included only debridement.

Alveolar Bone Loss↗

PubMed1991

Current research in diagnostic methods for assessing periodontal disease and its future impact.

A diagnostic test should be useful, ideally leading to a choice of treatment(s) that would confer benefits upon the patient. The many uses of diagnostic tests are listed in Table 2, but it should be recognized that no single test can be relied on exclusively. Combinations of various tests, especially those which detect infections and those which detect inflammation, would provide useful information for diagnosing and managing the patient's treatment. Certainly, any test or procedure can be considered useful if it facilitates the successful treatment of a patient's periodontal condition without a disproportionate increase in the cost to the patient or in his or her discomfort. By these criteria, many of the tests described in this paper are useful. The entry of these tests into clinical practice seems to be only a matter of time; their true usefulness is for the clinician to determine.

Clinical Enzyme Tests↗

PubMed1990

Rationale for the use of antimicrobial agents in periodontal disease.

The traditional approach to treating dental decay and periodontal disease has often focused on caries, neglecting periodontal infection. The past 15 years have seen significant advances in the treatment of periodontal disease with antimicrobial therapy, both with and without more traditional debridement or surgery. This article presents an overview of the use of antimicrobials, including an examination of treatment philosophies and the diagnosis of periodontal infection.

Adult↗

PubMed1990

The benzoylarginine peptidase from Treponema denticola (strain ASLM), a human oral spirochaete: evidence for active-site carboxyl groups.

The benzoylarginine peptidase of Treponema denticola (strain ASLM; a human oral spirochaete) was progressively and irreversibly inactivated by 1-(ethoxycarbonyl)-2-ethoxy-1, 2-dihydroquinoline, a carboxyl-group reagent. At acidic pH values, reaction of one mole of the modifier per active site of the enzyme resulted in total inactivation of the enzyme. Assuming that this modifier is a specific carboxyl reagent, the data suggest that the inactivation of the T. denticola benzoylarginine peptidase was caused by the modification of one carboxyl group located close to the active site of the enzyme. Results obtained with Woodward's reagent K (N-ethyl-5-phenylisoxazolium 3'-sulphonate) supported these findings. Carbethoxylation with diethylpyrocarbonate effectively inactivated the enzyme, and addition of hydroxylamine at pH 7.0 restored the activity almost totally, suggesting that the pyrocarbonate had reacted with tyrosyl or histidyl residues.

Binding Sites↗

PubMed1990

Benzoyl-arginine naphthylamide (BANA) hydrolysis by Treponema denticola and/or Bacteroides gingivalis in periodontal plaques.

Treponema denticola and Bacteroides gingivalis are among the few recognized species found in periodontal pockets that can hydrolyze the synthetic peptide N-benzoyl-DL-arginine-2-naphthylamide (BANA). We determined the presence of these periodontal pathogens in BANA-positive and -negative plaque samples through the use of indirect immunofluorescent antibody techniques. Eighteen of 27 diseased sites gave BANA-positive reactions, and 9 gave BANA-negative reactions. T. denticola was present in 16 of 18 BANA-positive reactions, whereas B. gingivalis was detected in 9 of the 18 BANA-positive reactions. T. denticola was present in 1 and B. gingivalis in 2 of the 9 BANA-negative reactions. Neither organism was detected in the 19 healthy sites that were negative for BANA. All measured differences between BANA-positive and BANA-negative plaques obtained in the same individuals were statistically significant. The accuracy of the BANA test, compared with clinical parameters such as bleeding upon probing and increased probing depth, was about 80%. The accuracy of the test in detecting the presence of T. denticola was 93%, for B. gingivalis, 76% and for T. denticola and/or B. gingivalis, 96%. This study indicated that BANA-positive plaques were associated with the presence of T. denticola and/or B. gingivalis, that T. denticola was found at a greater frequency and levels in BANA-positive plaques than B. gingivalis, and that the presence of these organisms was associated with clinical disease.

Adult↗

PubMed1990

Efficiency of split-mouth designs.

The purpose of this paper is (1) to investigate the similarity of the amount, distribution, and severity of periodontal disease of the within-patient experimental units, (2) to estimate the relative efficiencies of split-mouth designs when compared to whole-mouth designs, and (3) to discuss how stratification on initial pocket depth can result in large differences in the power of the test-statistics in the different disease categories. Periodontal disease characteristics are not always homogeneously distributed over the within-patient experimental units and this heterogeneity can reduce the efficiency of split-mouth designs. In particular, if analyses are stratified on initial pocket depth, sites with an initial probing depth deeper than 6 mm may be small in number and asymmetrically distributed when compared to sites with an initial probing depth less than 6 mm. This may result in large differences of the power of the test statistics among the different disease categories and should lead to a careful interpretation of the statistical significance tests. When disease characteristics are symmetrically distributed over the within-patient experimental units and a sufficient number of sites is present per experimental unit, the split-mouth design can provide moderate to large gains in relative efficiency. In the absence of a symmetric disease distribution, whole-mouth clinical trials may be preferable.

Adult↗

PubMed1990

Estimation of sensitivity and specificity of site-specific diagnostic tests.

Clinical trials designed to estimate the sensitivity and specificity of periodontal diagnostic tests often use multiple sites per patient as experimental units of analyses. Since site-specific test results within a patient are dependent observations, a correlated binomial model should be employed to estimate the sensitivity and specificity of these diagnostic tests. Ignoring the within-patient correlation can result in an over- or underestimation of the true standard errors.

Bacteroides↗

PubMed1990

Development of a diagnostic test for anaerobic periodontal infections based on plaque hydrolysis of benzoyl-DL-arginine-naphthylamide.

Treponema denticola, Porphyromonas (Bacteroides) gingivalis, and Bacteroides forsythus are among the anaerobic species frequently associated with adult forms of periodontal disease. These organisms hydrolyze the synthetic peptide benzoyl-DL-arginine-naphthylamide (BANA), and such enzyme activity can be detected in the plaque and related to clinical disease and the presence of spirochetes. In this investigation, the liquid BANA assay was compared with a commercially developed BANA assay which employed a paper format and which could be read after a 15-min incubation. In the paper format, strips of a Whatman filter paper were impregnated with BANA and strips of nitrocellulose paper were impregnated with fast black K salt. Both strips were applied lengthwise across a paper card (3 by 5 in. [7.6 by 12.7 cm]). The BANA strip at the bottom was inoculated with the test sample (pure culture, plaque), folded back so that it contacted the fast black strip, and then incubated for 15 min at 55 degrees C. T. denticola, P. gingivalis, and B. forsythus always gave a positive reaction, whereas 51 other plaque species were always negative. Six Bacteroides and Capnocytophaga species on occasion had weak reactions. The proportional agreement between BANA positiveness and clinical disease was similar for both the liquid and the paper assays. The sensitivity, specificity, and accuracy relative to the clinical standard of the liquid assay were 74, 76, and 77%, respectively, while those of the paper assay were 81, 78, and 80%, respectively. The paper assay was significantly associated with the presence of either T. denticola or P. gingivalis or both in the plaque samples, with a sensitivity of 85%, a specificity of 53%, and an accuracy of 79%. These findings indicate that a rapid paper assay for BANA hydrolysis gives data comparable to those obtained with the liquid BANA assay.

Arginine↗

PubMed1990

The utility of the BANA test for monitoring anaerobic infections due to spirochetes (Treponema denticola) in periodontal disease.

Treponema denticola, Porphyromonas gingivalis, and Bacteroides forsythus each possesses an enzyme(s) that hydrolyzes the synthetic substrate benzoyl-DL-arginine-naphthylamide (BANA). The presence of these organisms in a subgingival plaque sample can be determined by the ability of the plaque to hydrolyze BANA. In the present study, we describe the usefulness of the BANA test at various stages of a clinical trial of the efficacy of metronidazole in the treatment of periodontal disease. A BANA-positive test was significantly associated with high levels and proportions of spirochetes in the plaque, so that it provided information comparable with that which could be obtained by a microscopic examination of the plaque. Patients with such anaerobic spirochetal infections were randomly assigned to a group receiving either metronidazole or placebo (250 mg, three times a day) for one week and whose teeth were scaled and root-planed. The advantages of the decision that metronidazole be used were apparent from the comparison with the results obtained in the patients who received only the scaling and root planing. The initially BANA-positive teeth in the patients treated with metronidazole, scaling, and root planing gained attachment and exhibited a significant reduction in the need for periodontal surgery, when compared with the BANA-positive teeth in the patients who received only placebo, scaling, and root planing. After the conclusion of this therapy, those teeth with persistent BANA-positive plaques had significantly higher proportions and levels of spirochetes than did the teeth with BANA-negative plaques.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1990

Multi-center clinical evaluation of a chairside method for detecting certain periodontopathic bacteria in periodontal disease.

The association of bacteroides gingivalis, Bacteroides forsythus, Treponema denticola, and Actinobacillus actinomycetemcomitans among others with periodontal disease offers the opportunity for the development of diagnostic tests that are based upon the detection and/or quantification of one or more of these organisms or their by-products in the plaque. Three of the putative periodontal pathogens namely, T. denticola, B. gingivalis, and B. forsythus, can hydrolyze the synthetic trypsin substrate, N-benzoyl-DL-arginine-2-naphthylamide (BANA) forming a color reaction. The present investigation evaluated a commercially developed solid state assay for BANA hydrolysis that can be read after 15 minutes incubation at chairside. A total of 702 subgingival plaque samples were collected from 117 patients seen at four university dental clinics and placed on reagent cards. The color development on the cards was compared to the presence of T. denticola and B. gingivalis in the plaque, and with the clinical appearance of the sampled sites. This multi-center study demonstrated that antibodies to B. gingivalis and T. denticola could detect these organisms by an ELISA in the majority of the subgingival plaque samples. Comparable information could be obtained when the same plaques were evaluated by the reagent card format for BANA hydrolysis. The ELISA and reagent card were comparable in their ability to distinguish between clinically healthy and diseased sites. Both diagnostic procedures detected the periodontopathogens in plaques from sites that were judged clinically healthy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗