Walter J. Loesche

University of Michigan–Ann Arbor

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Walter A. Bretz

New York University

S. A. Syed

Jinnah Sindh Medical University

Dennis E. Lopatin

University of Michigan–Ann Arbor

Philippe P. Hujoel

University of Washington

Stephen A. Eklund

University of Michigan–Ann Arbor

Salam A. Syed

University of Michigan–Ann Arbor

Natalie S. Grossman

National Institute of Dental and Craniofacial Research

Margaret S. Terpenning

Eagle Mount

Brian A. Burt

University of Wisconsin–Madison

J. Stoll

University of Michigan–Ann Arbor

Cooperative Institutions

University of Michigan–Ann Arbor

126

National Institutes of Health

University of Groningen

National Institute of Dental and Craniofacial Research

Ann Arbor Center for Independent Living

Harvard University

Michigan United

University of Washington

University of Florida

University of California, San Francisco

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Effects of Metronidazole on Periodontal Treatment Needs

Journal of Periodontology (1991)

Walter J. Loesche Edgar Schmidt Billy A. Smith Edith C. Morrison Raúl G. Caffesse

P eriodontitis, 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 positivecontrol group had a decrease in the percentage of spirochetes ( P < 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. J Periodontol; 1991; 62:247– 257 .

10.1902/jop.1991.62.4.247

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Citations (132)

BACTEROIDES ORALIS, PROPOSED NEW SPECIES ISOLATED FROM THE ORAL CAVITY OF MAN

Journal of Bacteriology (1964)

Walter J. Loesche S. S. Socransky R.J. Gibbons

Loesche , W. J. (Forsyth Dental Center and Harvard School of Dental Medicine, Boston, Mass.), S. S. Socransky, and R. J. Gibbons . Bacteroides oralis , proposed new species isolated from the oral cavity of man. J. Bacteriol. 88: 1329–1337. 1964.—Twenty-seven strains of oral bacteroides were characterized and compared with a National Collection of Type Cultures strain of Bacteroides fragilis as well as strains of intestinal bacteroides. A combination of acid end products, gas production, pentose fermentation, and 10% bile tolerance afforded a basis for separation of oral strains from intestinal strains. The oral strains produced succinic, lactic, acetic, and formic acids but no gas. They were inhibited by 10% bile, and did not ferment xylose and arabinose. Intestinal strains consistent with the description for B. fragilis produced succinic, formic, acetic, and propionic acids and gas, with a few strains forming lactic acid. They were stimulated by 10% beef bile, and fermented xylose and arabinose. The oral strains are sufficiently different from intestinal strains of the B. fragilis type, so that they appear to constitute a separate species. It is proposed that they be recognized as B. oralis , sp. n.

Bacteroides fragilis

Arabinose

Bacteroidaceae

Streptococcus oralis

10.1128/jb.88.5.1329-1337.1964

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Citations (86)

Benefits of additional courses of systemic azithromycin in periodontal therapy.

General dentistry (2011)

Edgar Schmidt Niko Kaciroti Walter J. Loesche

The use of systemic antimicrobials such as doxycycline, metronidazole, and azithromycin in conjunction with debridement has achieved results superior to those produced by debridement alone. The purpose of the present study was to determine if previous results could be improved upon by administering repeated doses of azithromycin during the hygiene phase. One hundred patients with moderate to advanced periodontitis were treated with scaling and root planing plus three courses of azithromycin during the hygiene phase. All patients then were re-evaluated and periodontal surgery and/or extractions involving 96 teeth were performed in 32 patients. All patients then entered a maintenance program that lasted up to 192 weeks, with four-month recalls. Clinical parameters were recorded at baseline, at re-evaluation (week 6 after baseline), and at 96 and 192 weeks into maintenance. The results indicated that probing depths, bleeding upon probing, and suppuration were reduced significantly at re-evaluation. In addition, 14 teeth that displayed a Class III mobility at baseline improved to either Class I or Class II . There was no relapse during the maintenance phase. Multivariate analysis after 192 weeks indicated no change in the number of sites that bled upon probing, or had pockets that were 5.0-6.0 mm or ≥ 7 mm. Ninety-five percent of the sites that initially bled upon probing did not do so four years post-treatment. The results indicate that three courses of azithromicin in conjunction with root instrumentation during the hygiene phase led to long-lasting beneficial effects on all clinical parameters for at least 192 weeks.

Debridement (dental)

Treponema denticola

Bleeding on probing

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Citations (9)

Classification and distribution of large intestinal bacteria in nonhibernating and hibernating leopard frogs (Rana pipiens)

Applied and Environmental Microbiology (1988)

Jeffrey A. Banas Walter J. Loesche George W. Nace

The large intestinal flora of the leopard frog, Rana pipiens, was examined to determine whether differences existed between the nonhibernating and hibernating states of the animal and to determine the relative concentrations and proportions of potential frog pathogens. Hibernators had a logarithmic decrease of bacteria per milligram of intestine averaging one, and significantly greater proportions of facultative bacteria and psychrophiles relative to nonhibernators. The predominant anaerobic bacteria were gram-positive Clostridium species and gram-negative Bacteroides and Fusobacterium species. The predominant facultative bacteria were enterobacteria in nonhibernators but Pseudomonas species in hibernators. Many species of Pseudomonas are pathogenic for frogs, and thus the intestinal flora in hibernators may be a potential source of infectious disease.

Leopard frog

Facultative

10.1128/aem.54.9.2305-2310.1988

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Citations (27)

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

Molecular Microbiology (1990)

Kauko K. Mäkinen C.‐Y. Chen P.‐L. Mäkinen Kaoru Ohta Walter J. Loesche

Summary 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.

Treponema denticola

Hydroxylamine

Strain (injury)

10.1111/j.1365-2958.1990.tb00721.x

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Citations (5)

The Effects of Incubation Length and Temperature on the Specificity and Sensitivity of the BANA (N‐Benzoyl‐DL‐Arginine‐Naphthylamide) Test

Journal of Periodontology (1993)

Joseph Amalfitano Anna B. De filippo Walter A. Bretz Walter J. Loesche

A previous multi‐center study examining patients diagnosed as having at least four periodontally diseased teeth showed that when BANA (N‐Benzoyl‐DL‐Arginine‐Naphthylamide) hydrolysis by periodontal pathogens such as Treponema denticela, Porphyromonas gingivalis , and Bacteroides forsythus was evaluated versus clinical parameters such as clinical judgment of disease, bleeding on probing, and pocket depth, the sensitivity of the test was 84%, 82%, and 87%, respectively, while the specificity was only 42%, 41%, and 32%, respectively. The purpose of the present investigation was to improve the specificity of the test while retaining a high level of sensitivity in both gingivally healthy and periodontally diseased groups. One hundred forty‐nine patients participated in this study providing 3,497 interproximal plaque samples. Gingival health was measured using the papillary bleeding score and this was compared with the presence or absence of detectable trypsin‐like activity, as determined by the BANA hydrolysis of interproximal plaque samples, using a commercially‐available test. Sensitivity and specificity were measured by varying the incubation time and temperature of the enzymatic assay. Using the correlated binomial model to analyze site‐specific data within a patient, the specificity was highest at 35°C and 5 minutes incubation (94%), and lowest at 45°C and 15 minutes incubation (33%). Sensitivity was highest at 45°C or 55°C and 15 minutes incubation (90%) and lowest at 35°C and 5 minutes incubation (47%). When the sensitivity and specificity of the test run at 35°C for 5 minutes were used in a model for a diagnostic test proposed by Douglass and Fox, the test has utility when used on older general dental patients and for periodontal patients. J Periodontol 1993; 64:848–852.

Treponema denticola

Incubation period

10.1902/jop.1993.64.9.848

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Citations (21)

MORPHOLOGY OF TREPONEMA MICRODENTIUM AS REVEALED BY ELECTRON MICROSCOPY OF ULTRATHIN SECTIONS

Journal of Bacteriology (1963)

Max A. Listgarten Walter J. Loesche S. S. Socransky

Listgarten , M. A. (Harvard School of Dental Medicine and Forsyth Dental Infirmary, Boston, Mass.), W. J. Loesche, and S. S. Socransky . Morphology of Treponema microdentium as revealed by electron microscopy of ultrathin sections. J. Bacteriol. 85: 932–939. 1963.—Broth cultures of a strain of Treponema microdentium were harvested on Millipore filters, fixed in osmic acid, and sectioned for electron microscopy. The sections revealed that the spirochetes had an axial filament, made up of two fibrils approximately 150 A in diameter, which was situated between an external envelope approximately 140 A in thickness and a protoplasmic cylinder. The protoplasmic cylinder had a cross-sectional diameter of 100 to 200 mμ, and was surrounded by a double “membrane” consisting of two 40-A electron-dense structures separated by a 45-A space. Cross-sections of spirochetal “granules” revealed that the limiting membrane was continuous with the outer envelope of the spirochetes, and surrounded the protoplasmic cylinder and axial filament.

Protoplasm

Morphology

Electron micrographs

Microtome

10.1128/jb.85.4.932-939.1963

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Citations (26)

API ZYM system for identification of Bacteroides spp., Capnocytophaga spp., and spirochetes of oral origin

Journal of Clinical Microbiology (1982)

Barbara E. Laughon S. A. Syed Walter J. Loesche

A total of 80 oral strains of Bacteroides gingivalis, B. asaccharolyticus, B. melaninogenicus subsp. intermedius, B. melaninogenicus subsp. melaninogenicus, Capnocytophaga, Treponema denticola, and T. vincentii were characterized with the API ZYM system for 19 enzyme activities. Comparison of anaerobic and aerobic incubation with nine reference strains of these organisms showed no important differences. The key differential tests for black-pigmented Bacteroides strains and treponemes of oral origin were trypsin, alpha-glucosidase, and N-acetyl-beta-glucosaminidase. All Capnocytophaga strains produced distinctive aminopeptidase activities but varied in their glycosidic capabilities. The presence of a trypsin-like activity in B. gingivalis, T. denticola, and a group of Capnocytophaga strains may contribute to tissue destruction in periodontal disease.

Capnocytophaga

Treponema denticola

10.1128/jcm.15.1.97-102.1982

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Citations (279)

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

PubMed (1992)

Walter J. Loesche

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.

Debridement (dental)

Clinical Significance

Antibiotic Therapy

Dental plaque

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Citations (45)

Histopathologic and bacterial evaluation of conventional and new copper amalgams

Journal of Oral Pathology and Medicine (1979)

Donald R. Heys Charles F. Cox Ronald J. Heys Walter J. Loesche James K. Avery

In vivo pulpal responses in monkeys and in vitro bacterial inhibition studies were completed on new copper amalgams, Sybraloy, Dispersalloy, Tytin and a conventional Spheraloy amalgam. Amalgams were placed in cavities lined with ZOE and in unlined cavities. Silicate and ZOE were used as controls. A total of 165 adult monkey teeth were evaluated at 3 days, 5 and 8 weeks. At 3 days the pulpal responses elicited by the copper amalgams appeared similar to conventional Spheraloy, all showing a slight to moderate response. At 5 weeks the majority of amalgams exhibited a slight pulpar response with a tubular reparative dentin under each restoration. The 8 week pulpal response showed a reduction of the inflammatory response characterized by a tubular reparative dentin with a uniform zone of predentin. Lined ZOE controls exhibited a slight response while silicate showed a moderate response with some persistent chronic inflammation. In vitro bacterial tests revealed that the various amalgams had little to no inhibitory effect on the three serotypes of S. mutans that are most prominent in humans.

Amalgam (chemistry)

Inflammatory response

10.1111/j.1600-0714.1979.tb01626.x

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Citations (10)