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

Efficacy of antimicrobial peptide P113 oral health care products on the reduction of oral bacteria number and dental plaque formation in a randomized clinical assessment

Background/purpose

Dental plaque is the main cause leading to the dental caries and periodontal diseases. The main purpose of this study was to test the efficacy of oral spray containing the antimicrobial peptide P-113 on the reduction of oral bacteria number and dental plaque formation in a randomized clinical assessment.

Materials and methods

This study was divided into two parts. In Part A, we investigated the user experiences with the P-113 containing oral spray. In part B, 14 subjects in the experimental group used the P-113-containing oral spray, while 14 subjects in the control group used a placebo without the P-113 in a 4-week clinical trial. Participants were asked to use the P-113-containing oral spray or placebo 3 times per day and 5 times per use. Moreover, 3 check-ups and 2 washouts were carried out to evaluate the DMFT score, dental plaque weight, dental plaque index, and gingival index.

Results

In part A, up to 91.8% of the subjects in the experimental group were satisfied with the use of the P-113-containing oral spray. In part B, based on our PacBio SMRT sequencing platform and DADA2 analysis, the numbers of Streptococcus and Porphyromonas in the experimental group were lower than those in the control group. In addition, decreased dental plaque weight, dental plaque index, and gingival index were all observed in the experimental group.

Conclusion

The P-113-containing oral spray has the potential to reduce the dental caries and periodontal disease-related bacteria and to control the dental plaque formation.

Evaluation of the ability of the trypsin-like peptidase activity assay to detect severe periodontitis

OBJECTIVES

N-benzoyl-DL-arginine peptidase (trypsin-like peptidase) is specifically produced by certain strains of periodontitis-associated bacteria. We aimed to examine the effectiveness of an objectively quantified trypsin-like peptidase activity assay (TLP-AA) for detecting severe periodontitis.

METHODS

The study population included 347 adults (108 men and 239 women; average age, 43.3 years) who underwent a full-mouth periodontal examination. Specimens for the TLP-AA were obtained using tongue swabs. Using a color reader, the TLP-AA results were obtained as a* values, with higher positive a* values indicating an increased intense enzymatic activity. The predictive validity of the TLP-AA results for severe periodontitis was assessed using receiver operating characteristic curve analysis and the periodontitis case definition provided by the Centers for Disease Control and Prevention/American Academy of Periodontology as the gold standard. Furthermore, multivariable logistic regression analyses were performed to predict severe periodontitis using the TLP-AA results and health characteristics, as the exposure variables.

RESULTS

Severe periodontitis was observed in 5.2% of the participants. TLP-AA had high diagnostic accuracy for severe periodontitis, with an area under the curve of 0.83 (95% confidence interval [CI]: 0.75-0.92). The cut-off score for the a* value that best differentiated individuals with severe periodontitis was 0.09, with a sensitivity of 83% and specificity of 77%. Multivariable logistic regression analyses revealed that the TLP-AA results were significantly associated with severe periodontitis after adjusting for health characteristics (adjusted odds ratios: 1.90 [95% CI: 1.37-2.62] for the a* value).

CONCLUSIONS

Objectively quantified TLP-AA results are potentially useful for detecting severe periodontitis in epidemiological surveillance.

A Preliminary Study on the Ability of the Trypsin-Like Peptidase Activity Assay Kit to Detect Periodontitis

This study aimed to explore whether the Trypsin-Like Peptidase Activity Assay Kit (TLP-AA-Kit), which measures the activity of N-benzoyl-dl-arginine peptidase (trypsin-like peptidase), can be used as a reliable tool for periodontitis detection in population-based surveillance. In total, 105 individuals underwent a full-mouth periodontal examination and provided tongue swabs as specimens for further analyses. The results of the TLP-AA-Kit were scored between 1 and 5; higher scores indicated higher trypsin concentrations. Receiver operating characteristic analyses were used to evaluate the predictive validity of the TLP-AA-Kit, where the periodontitis case definition provided by the Centers for Disease Control/American Academy of Periodontology served as the reference. Severe and moderate periodontitis were identified in 4.8% and 16.2% of the study population, respectively. The TLP-AA-Kit showed high diagnostic accuracy for severe periodontitis, with an area under the curve of 0.93 (95% confidence interval = 0.88-0.99). However, the diagnostic accuracy of the TLP-AA-Kit for moderate/severe periodontitis was not reliable. While further studies are necessary to validate our results, the results provided herein highlight the potential of the TLP-AA-Kit as a useful tool for the detection of periodontitis, particularly in severe cases, for population-based surveillance.

Red complex: Polymicrobial conglomerate in oral flora: A review

Oral diseases are the complex host responses composed of a broad array of inflammatory cells, and cytokines, chemokines, and mediators derived from the cells resident in the gingival tissues, as well as from the emigrating inflammatory cells. A chronic polymicrobial challenge to the local host tissues triggers this response, which under certain circumstances, and in a subset of the population, leads to the progressing soft and hard tissue destruction that characterizes periodontitis. The red complex has been proposed as a pathogenic consortium, consisting of P. gingivalis, T. denticola, and T. forsythia. This review has attempted to examine the virulence potential and determinants of these commensal opportunists.

Halitosis: From diagnosis to management

Halitosis is formed by volatile molecules which are caused because of pathological or nonpathological reasons and it originates from an oral or a non-oral source. It is very common in general population and nearly more than 50% of the general population have halitosis. Although halitosis has multifactorial origins, the source of 90% cases is oral cavity such as poor oral hygiene, periodontal disease, tongue coat, food impaction, unclean dentures, faulty restorations, oral carcinomas, and throat infections. Halitosis affects a person's daily life negatively, most of people who complain about halitosis refer to the clinic for treatment but in some of the people who can suffer from halitosis, there is no measurable halitosis. There are several methods to determine halitosis. Halitosis can be treated if its etiology can be detected rightly. The most important issue for treatment of halitosis is detection etiology or determination its source by detailed clinical examination. Management may include simple measures such as scaling and root planning, instructions for oral hygiene, tongue cleaning, and mouth rinsing. The aim of this review was to describe the etiological factors, prevalence data, diagnosis, and the therapeutic mechanical and chemical approaches related to halitosis.

Acidogenic Potential of “Sugar-Free” Cough Drops

A patient presented with extensive marginal ditching around restorations recently placed during whole-mouth rehabilitation. The patient was not xerostomic and was otherwise normal except for the self-reported excessive use of “sugar-free” cough drops sweetened with sorbitol and Isomalt® (an equimolar mix of glucosyl-mannitol and glucosylsorbitol). This prompted anin vitroinvestigation to determine whetherStreptococcus sobrinus6715, a cariogenic streptococcus, could grow and produce acid in growth medium containing an aqueous extract of such “sugar-free” cough drops. The results indicate thatS. sobrinus6715 uses Isomalt® and sorbitol extensively, producing terminal culture pH as low as 4.2 when grown on medium with cough drop extract containing these sugars. This pH is sufficient to demineralize dental enamel. Patients should be cautioned against the chronic overuse of “sugar-free” cough drops and other “sugar-free” confections sweetened with a mixture of Isomalt® and sorbitol.

Prevotella copri sp. nov. and Prevotella stercorea sp. nov., isolated from human faeces

Six strains (CB7(T), CB18, CB23, CB26, CB28 and CB35(T)) were isolated from human faeces. Based on phylogenetic analysis, phenotypic characteristics, cellular fatty acid profiles and menaquinone profiles, these strains could be included within the genus Prevotella and made up two clusters. 16S rRNA gene sequence analysis indicated that five strains were most closely related to Prevotella veroralis, sharing about 92 % sequence similarity; the remaining strain was most closely related to Prevotella shahii, sharing about 90 % sequence similarity. All six strains were obligately anaerobic, non-pigmented, non-spore-forming, non-motile, Gram-negative rods. The cellular fatty acid compositions of the six strains differed significantly from those of other Prevotella species. Five strains (CB7(T), CB18, CB23, CB26 and CB28) contained dimethyl acetals and the major menaquinones of these strains were MK-11, MK-12 and MK-13. The major menaquinones of CB35(T) were MK-12 and MK-13. Based on phenotypic and phylogenetic findings, two novel species, Prevotella copri sp. nov. and Prevotella stercorea sp. nov., are proposed, representing the two different strain clusters. The DNA G+C contents of strains CB7(T) and CB35(T) were 45.3 and 48.2 mol%, respectively. The type strains of P. copri and P. stercorea are CB7(T) (=JCM 13464(T)=DSM 18205(T)) and CB35(T) (=JCM 13469(T)=DSM 18206(T)), respectively.

Antimicrobial treatment of Capnocytophaga infections

Capnocytophaga spp. are normal inhabitants of the oropharyngeal flora. They are also involved in periodontal diseases or animal bites, complicated by septicaemia with dissemination to a great variety of sites, both in immunocompetent and immunocompromised hosts. This review will focus on their pathogenesis, spectrum of clinical infections and susceptibility to disinfectants and antibiotics. The spread of beta-lactamase-producing strains limits the use of beta-lactams as first-line treatments, underlying the necessity to test the in vitro susceptibility of clinical strains. Many antimicrobial treatments have been used, despite an absence of randomised studies and guidelines regarding the duration of treatment according to infected sites. Imipenem/cilastatin, clindamycin or beta-lactamase inhibitor combinations are always effective and their use can be recommended in all infections.

Reclassification of Bacteroides distasonis, Bacteroides goldsteinii and Bacteroides merdae as Parabacteroides distasonis gen. nov., comb. nov., Parabacteroides goldsteinii comb. nov. and Parabacteroides merdae comb. nov

The characteristics of three Bacteroides species, Bacteroides distasonis, Bacteroides goldsteinii and Bacteroides merdae, were examined. 16S rRNA gene sequence analysis showed that B. distasonis, B. goldsteinii and B. merdae should not be classified as species within the genus Bacteroides. Although B. distasonis, B. goldsteinii and B. merdae were phylogenetically related to Tannerella forsythensis, the ratios of anteiso-C15 : 0 to iso-C15 : 0 in whole-cell methanolysates of the three species were different from that of T. forsythensis. In addition, whereas the major menaquinones of T. forsythensis were MK-10 and MK-11, the major menaquinones of B. distasonis, B. goldsteinii and B. merdae were MK-9 and MK-10. The three species were phenotypically similar to Bacteroides sensu stricto, but phylogenetically distinct. Furthermore, B. distasonis, B. goldsteinii and B. merdae could be differentiated from Bacteroides sensu stricto (predominant menaquinones: MK-10 and MK-11) by the menaquinone composition. This is an important chemotaxonomic characteristic of the three species. On the basis of these data, a novel genus, Parabacteroides gen. nov., is proposed for B. distasonis, B. goldsteinii and B. merdae, with three species, Parabacteroides distasonis gen. nov., comb. nov. (the type species), Parabacteroides goldsteinii comb. nov. and Parabacteroides merdae comb. nov. The type strains of P. distasonis, P. goldsteinii and P. merdae are JCM 5825T (=CCUG 4941T=DSM 20701T=ATCC 8503T), JCM 13446T (=CCUG 48944T) and JCM 9497T (=CCUG 38734T=ATCC 43184T), respectively.

The metabolism of cholesterol and certain hormonal steroids by Treponema denticola

The aim was to investigate whether reference cultures and fresh isolates of Treponema denticola are able to 5alpha-reduce and further metabolise testosterone, 4-androstenedione, progesterone, corticosterone, cortisol or cholesterol. Two reference and five freshly isolated cultures of T. denticola were incubated with either radiolabeled or unlabeled steroid substrates; in the first case products were identified by thin layer chromatography and in the latter by gas chromatography-mass spectroscopy. All the substrates were 5alpha-reduced. Both reference cultures and fresh isolates of T. denticola presented 3beta- and 17beta-hydroxy steroid dehydrogenase activity. It was concluded that T. denticola was capable of steroid metabolism and hypotheses are discussed regarding the in vivo function of this metabolism including, T. denticola utilising host supplied steroids as growth factors and T. denticola steroid metabolism acting as a virulence factor.

Capnocytophaga in the dental plaque of immunocompromised children with cancer

OBJECTIVES

(i) To compare the prevalence and levels of Capnocytophaga, a known systemic pathogen in immunocompromised patients, in the dental plaque of healthy children and children with cancer, and (ii) to determine the susceptibility of strains isolated from cancer patients to a range of antibiotics.

PATIENTS AND METHODS

Thirty-one children with cancer undergoing a first course of immunosuppressive chemotherapy and 30 healthy control children were included in the study. Samples were collected on days 0, 7, 14, and 21 of the cure (and equivalent dates in controls). Susceptibility to antibiotics was tested using an agar dilution method and galleries with predefined concentrations of selected antibiotics.

RESULTS

There was a significant drop in the total anaerobic cultivable flora on day 14 and in the prevalence of Capnocytophaga on days 14 and 21 in the children with cancer. The proportion of Capnocytophaga in the anaerobic flora, however, was high in certain cancer patients. Beta-lactam/beta-lactamase inhibitor combinations, imipenem, clindamycin, and tetracycline were the most effective against Capnocytophaga.

CONCLUSION

This study showed that Capnocytophaga decreased in prevalence and proportion in the dental plaque of cancer patients during chemotherapy but became predominant in some cases. It is recommended that imipenem or beta-lactam/beta-lactamase inhibitor combinations be used to treat Capnocytophaga bacteraemia.

Professional oral care reduces influenza infection in elderly

Influenza is a major cause of respiratory infection and has a high mortality rate in the elderly. Neuraminidase (NA) on the surface of the influenza virus and bacterial trypsin-like proteases (TLP) play key roles in influenza virus infections. We investigated the effects of oral care on influenza, evaluating in particular the activities of NA and TLP in saliva, as they may contribute to an increased risk of infection with influenza. One hundred ninety elderly patients who visited day care service facilities once a week were randomly assigned to either a professional oral care group or to an own oral care group as the control group. Nine individuals in the control group and one person in the professional oral care group were diagnosed with influenza during the follow-up period. The relative risk of developing influenza while under professional oral care compared to that in the control group was 0.1 (95% CI 0.01-0.81, p=0.008). Significant decreases in numbers of salivary anaerobic bacterial CFUs, and NA and TLP levels were observed in the professional oral care group compared to that in the control group (p<0.01). This study suggests that maintenance of oral hygiene is effective in the prevention of influenza in the elderly.

Prevotella multisaccharivorax sp. nov., isolated from human subgingival plaque

Six bacterial strains isolated from the human oral cavity, PPPA16, PPPA20T, PPPA24, PPPA31, EPPA6 and EPPA7, were characterized by determining phenotypic and biochemical features, cellular fatty acid profiles, menaquinone profiles and phylogenetic position based on 16S rRNA gene sequence analysis. 16S rRNA gene sequence analysis showed that the isolates represented the same species of the genus Prevotella. The strains were related to Prevotella dentalis with about 89 % similarity. In addition, the isolates were related to Prevotella sp. oral clone IDR-CEC-0032, which is a representative of the numerically dominant cluster VI in carious dentine lesions [Nadkarni et al. (2004). J Clin Microbiol 42, 5238–5244], with about 99 % similarity. The strains were obligately anaerobic, non-pigmenting, non-spore-forming, non-motile, Gram-negative rods. The isolates could be differentiated from other Prevotella species by d-mannitol, d-melezitose, d-sorbitol and d-trehalose fermentation in API 20A tests. The cellular fatty acid composition of strains PPPA16, PPPA20T, PPPA24, PPPA31, EPPA6 and EPPA7 was significantly different from that of other Prevotella species. Compared with other Prevotella species, only these six strains contained dimethyl acetals. The major menaquinones of the clinical isolates were MK-12 and MK-13, whereas the major menaquinones of other Prevotella species were MK-10 and MK-11. On the basis of these data, a novel Prevotella species, Prevotella multisaccharivorax sp. nov., is proposed, with PPPA20T (=JCM 12954T=DSM 17128T) as the type strain.

Molecular identification of Capnocytophaga spp. via 16S rRNA PCR-restriction fragment length polymorphism analysis

Capnocytophaga spp. have been implicated as putative periodontal pathogens associated with various periodontal diseases. Although the genus is known to contain five human oral isolates, accurate identification to species level of these organisms recovered from subgingival plaque has been hampered by the lack of a reliable method. Hence, most studies to date have reported these isolates as Capnocytophaga spp. Previous attempts at identification were based on biochemical tests; however, the results were inconclusive. Considering the differing virulence features of the respective isolates, it is crucial to identify these isolates to species level. The universal and conservative nature of the 16S rRNA gene has provided an accurate method for bacterial identification. The aim of this study was to identify Capnocytophaga spp. via restriction enzyme analysis of this gene (16S rRNA PCR-restriction fragment length polymorphism). The results (backed up by 16S rRNA gene sequencing) showed that this method reliably identifies all named Capnocytophaga spp. to species level.

Isolation and characterization of aminopeptidase from Capnocytophaga granulosa ATCC 51502

There is evidence that enzymes from the genus Capnocytophaga play a role in dental calculus formation. Although most of the species in the genus produce aminopeptidases, there is a paucity of data on the purification and characterization of the enzyme, except in the case of Capnocytophaga gingivalis. The aim of this study was to purify aminopeptidase from culture supernatant of Capnocytophaga granulosa ATCC 51502, a new species of the genus. Purification was performed using ammonium sulfate fractionation and two chromatographic steps. The aminopeptidase was purified 158,433-fold with a yield of 12.0%. The enzyme appeared to be a trimer with a molecular mass of 270 kDa. The optimal pH of the aminopeptidase was 6.5 and its activity was completely inhibited by incubation at 50 degrees C for 10 min. The enzyme showed maximum specificity for basic amino acids (Arg and Lys) and also hydrolyzed noncharged amino acids (Met, Leu and Ala). Ca(2+), Zn(2+) and Fe(3+) activated the enzyme, while EDTA, Ag(+), Hg(+) and Cu(2+) inhibited it. These results suggest that aminopeptidase of C. granulosa is different from that of C. gingivalis but similar to aminopeptidase B.

Prevotella multiformis sp. nov., isolated from human subgingival plaque

Four bacterial strains isolated from the human oral cavity, PPPA19, PPPA21T, PPPA28 and PPPA30, were characterized by determining phenotypic and biochemical features, cellular fatty acid profiles and the phylogenetic position based on 16S rRNA gene sequence analysis. 16S rRNA gene sequence analysis showed that each of the isolates was a member of the genus Prevotella. These strains were related to Prevotella denticola with about 95 % similarity. The strains were obligately anaerobic, non-pigmented, non-spore-forming, non-motile, Gram-negative rods. However, the cells of these strains were often cocci (coccobacilli), depending on the cultivation time. Colonies of different sizes were detected on Eggerth Gagnon agar plates for these strains. The cells forming large colonies were cocci, whereas those forming small colonies were cocci and rods. However, 16S rRNA gene sequence comparison of colonies of different sizes revealed that only a single organism was present. Although these strains had phenotypic characteristics that were similar to those of P. denticola JCM 8528, they could be differentiated from P. denticola JCM 8528 by aesculin hydrolysis and d-cellobiose fermentation in API 20A tests. DNA–DNA hybridization experiments revealed the genomic distinction of these four strains with respect to P. denticola JCM 8528. On the basis of these data, a novel Prevotella species, Prevotella multiformis sp. nov., is proposed, with PPPA21T (=JCM 12541T=DSM 16608T) as the type strain.

Prevotella shahii sp. nov. and Prevotella salivae sp. nov., isolated from the human oral cavity

Two bacterial strains, EHS11T and EPSA11T, which were isolated from the human oral cavity, were characterized in terms of phenotypic and biochemical characteristics, cellular fatty acid profiles and phylogenetic position based on 16S rRNA gene sequence analysis. 16S rRNA gene sequence analysis showed that each of the isolates belonged to a novel species of the genus Prevotella. Strain EHS11T was related to Prevotella loescheii (about 95 % similarity), whereas strain EPSA11T was related to Prevotella oris (about 94 % similarity). Both strains were obligately anaerobic, non-pigmented, non-spore-forming, non-motile, Gram-negative rods. The cellular fatty acid composition of strain EPSA11T was very similar to that of P. oris JCM 8540T. On the other hand, the cellular fatty acid composition of strain EHS11T was significantly different from those of other Prevotella species. The predominant fatty acids in strain EHS11T are C18 : 1 ω9c, C16 : 0 and C16 : 0 3-OH, whereas other Prevotella species, except for P. loescheii JCM 8530T, possess anteiso-C15 : 0, iso-C17 : 0 3-OH and C18 : 1 ω9c. The predominant fatty acids in P. loescheii JCM 8530T are anteiso-C15 : 0, C16 : 0 and C18 : 1 ω9c. DNA–DNA hybridization experiments revealed a genomic distinction of strains EHS11T and EPSA11T from P. loescheii JCM 8530T and P. oris JCM 8540T. On the basis of these data, two novel Prevotella species are proposed: Prevotella shahii sp. nov. and Prevotella salivae sp. nov. The type strains of P. shahii and P. salivae are EHS11T (=JCM 12083T=DSM 15611T) and EPSA11T (=JCM 12084T=DSM 15606T), respectively.

Gingival crevicular fluid levels of aspartate amino transferase, sulfide ions and N-benzoyl-DL-arginine-2-naphthylamide in diabetic patients with chronic periodontitis

BACKGROUND

The aim of this study is to analyze the correlations between plaque index (PlI), gingival index (GI), probable pocket depth (PPD), clinical attachment level (CAL), aspartate aminotransferase (AST), N-benzoyl-DL-arginine-2-naphthylamide (BANA) and sulfide ion activity (SIA) of diabetic patients with chronic periodontitis with regard to disease activity detected by AST levels.

MATERIAL AND METHODS

A total of 95 sites from eight diabetic patients with chronic periodontitis and 74 sites from eight systemically healthy patients with chronic periodontitis were enrolled in the study. The patients had no history of periodontal treatment or any antibiotic therapy during the last 6 months and were nonsmokers. All the sites selected for the study had a CAL of at least 2 mm. Gingival crevicular fluid volumes (GCFV) were measured in all sites.

RESULTS

According to the result of AST analysis, 45 sites were AST positive and 50 were AST negative in the diabetic group and 36 sites were AST positive and 38 were AST negative in the control group. There was a significant correlation between BANA hydrolysis and PPD in both diabetic and control groups, but no correlation between PPD and AST levels. A significant correlation was observed between AST-positive sites and GI, but not between GI and BANA hydrolysis. In both groups, the correlation between SIA and BANA hydrolysis was significant, but no correlation was revealed between SIA and AST levels in either diabetic or control groups.

CONCLUSION

The GCF metabolites had significant correlations with periodontally diseased sites in patients with chronic periodontitis, whether diabetic or systemically healthy, and may help to confirm clinical findings.

Genetic analysis of an ambler class A extended-spectrum beta-lactamase from Capnocytophaga ochracea

A beta-lactamase gene (cfxA3, 966 bp) was isolated from a beta-lactam-resistant Capnocytophaga ochracea clinical isolate and amplified using primers from the cfxA gene of Bacteroides vulgatus. The MICs of third-generation cephalosporins were much higher than those of the transconjugant Escherichia coli strain. The deduced protein sequence, by comparison with CfxA2 of Prevotella intermedia, had a Y239D substitution and possessed the characteristics of a class A, group 2e beta-lactamase.

Effect of triclosan dentifrices on mouth volatile sulphur compounds and dental plaque trypsin-like activity during experimental gingivitis development

BACKGROUND

The objective of this study was to evaluate the effect of three commercial anti-plaque dentifrices containing 0.3% triclosan + 2% pvm/ma (Colgate Total), 0.3% triclosan + 0.75% Zn (Signal Global) and 0.3% triclosan + 5% PPi (Crest Complete) in comparison with an experimental dentifrice (0.3% triclosan + 2% pvm/ma + 0.75% Zn + 4% PPi) and a control dentifrice without anti-plaque agents on trypsin-like activity in dental plaque (detected by the hydrolysis of [Na-Benzoyl-DL-Anginine p-Nitroanilide (BAPNA)] and volatile sulphur compounds (VSCs) in mouth air during experimental gingivitis development.

METHOD

A 5-step double blind, crossover experimental gingivitis study was conducted on 19 volunteers during a 21-day period. The volunteers refrained from brushing an experimental quadrant of teeth. The dentifrices were applied to those teeth via toothshield three times per day; simultaneously they brushed the other teeth with the same dentifrice. After each period, VSCs in mouth air and BAPNA hydrolysis by dental plaque accumulated in the experimental quadrant were determined.

RESULTS

There was an increase (p < 0.05) in VSCs in mouth air when experimental gingivitis was induced in only one quadrant of teeth. None of the dentifrices was able to avoid the increase of VSCs during the experimental gingivitis development. The majority of the antiplaque dentifrices evaluated reduced the increase of VSC formation in comparison with the control (p < 0.05). There was no relationship between the ability of the dentifrices in reducing VSC formation and the inhibition of trypsin-like activity in dental plaque.

CONCLUSIONS

Anti-plaque dentifrices reduce the increase of VSCs that occurs during the development of experimental gingivitis.

Retrospective assessment of clinical and microbiological factors affecting periimplant tissue conditions

An increasing number of studies point to the detrimental effect of plaque bacteria on periimplant tissue health. The purpose of this retrospective study was to explore a possible relationship between the clinical and microbiological periimplant conditions of osseointegrated oral implants after several years of service and the dental and medical history, as well as the conditions of the residual dentition. 45 partially edentulous patients (mean age: 51 years, range: 27-83 years), with a total of 64 implants participated in this retrospective analysis. The time between examination and the last dental visit ranged from 6 to 24 months (mean: 13 months) and the time since the last maintenance therapy appointment with a dental hygienist ranged between 3 and 24 months (mean 7 months). During 5 to 10 years between implant installation and examination, 9 implants experienced one episode and an additional 6 implants two episodes of periimplantitis. As a consequence of extensive bone loss associated with these infections, one of these implants, in a patient who had a history of diabetes, was lost. With this exception, the other episodes of periimplantitis were successfully treated employing the principles of the Cumulative Interceptive Supportive Therapy (CIST) protocol. At examination, 42 implants (66%) showed a probing pocket depth exceeding 4 mm. Of the periimplantitis sites, four implants showed cultural evidence for presence of Porphyromonas gingivalis, and 2 implants were positive for Actinobacillus actinomycetemcomitans. Statistical analysis revealed a significant relationship between periimplant probing depth and the total anaerobic cultivable microbiota as well as the frequency of detection of P. gingivalis.

Association of early onset periodontitis microbiota with aspartate aminotransferase activity in gingival crevicular fluid

OBJECTIVES

The objective of this study was to determine the relationship between the activity of the enzyme aspartate aminotransferase (AST) in gingival crevicular fluid (GCF) using the colorimetric PerioGard (PTM) test and the subgingival microflora in early onset periodontitis lesions.

MATERIAL AND METHODS

The study population consisted of 25 otherwise healthy individuals exhibiting early onset periodontitis (EOP). In each patient four experimental sites were identified comprising one deep periodontal pocket (PD >5 mm) randomly chosen in each quadrant. Bacterial samples were obtained from the experimental sites, consecutively cultured anaerobically and in 10% CO(2) using selective and nonselective media. Isolates were characterized to species level by conventional biochemical tests and various identification kits. Clinical measurements as well as AST activity, assessed either as positive or negative using the PTM, were recorded at the same sites.

RESULTS

Sixty-two sites exhibited AST positive and 38 AST negative activity. Analysis of bacterial counts using the ANOVA (Mann Whitney U-test) showed that Streptococcus intermedius, Peptostreptococcus micros, Campylobacter concisus, Bacteroides forsythus, Camplobacter gracilis, Campylobacter rectus and Selenomonas sputigena were significantly higher in sites with AST-positive activity. The odds ratio of having high prevalence of S. intermedius, P. micros, C. concisus, B. forsythus, C. gracilis, C. rectus and S. sputigena in the presence of a positive AST site was very high (range: 3.5-17.0). Streptococcus sanguis, Actinomyces naeslundii, Gemella morbillorum, Capnocytophaga gingivalis, Veillonella parvula, Fusobacterium varium, Eubacterium lentum and Prevotella oralis were detected in significantly higher proportions in sites with AST negative activity and manifested a negative odds ratio in the presence of AST positive sites. The logistic regression analysis revealed that smoking and bleeding upon probing showed a significant association with AST activity, while plaque and suppuration were not found to be significant predictors of AST activity. The co-infection of Porphyromonas gingivalis, B. forsythus and P. micros, or P. gingivalis, B. forsythus and C. rectus were found to be significantly associated with the AST activity (p<0.001). AST positive sites revealed significantly higher occurrence of co-infections by P. gingivalis, B. forsythus, S. sputigena or by P. gingivalis, B. forsythus, S. intermedius than AST negative sites (p<0.001). P. gingivalis, B. forsythus, A. naeslundii co-infection was found significantly higher in the AST negative sites (p<0.001).

CONCLUSIONS

The present study found a high level of agreement between the presence of putative periodontal pathogens and positive AST scores at periodontal sites that clinically were considered to be potentially disease active. Prospective studies should be performed to confirm the findings.

Capnocytophaga granulosa and Capnocytophaga haemolytica: novel species in subgingival plaque

BACKGROUND

The oral cavity accommodates one of the most diverse microfloras in the human body. Knowledge of this microflora, and of the periodontal microflora in particular, proves crucial towards an understanding of the bacterial-host interactions which lead to the development of infectious inflammatory periodontal diseases. Capnocytophaga species have been implicated as putative periodontal pathogens. To date, only 3 members of this genus (C. gingivalis, C. ochracea and C. sputigena) have been isolated from subgingival plaque.

AIM

This communication reports the isolation of 2 recently-speciated strains, namely C. granulosa and C. haemolytica, from subgingival plaque collected from adult periodontitis patients.

MATERIAL AND METHODS

Subgingival plaque was collected from 29 patients with chronic adult periodontitis. Plaque samples were inoculated onto fastidious anaerobe agar and incubated anaerobically for 5 days. Routine identification of clinical isolates was performed by 16S rRNA PCR-RFLP analysis, using Cfo I as restriction enzyme and corroborated by 16S rRNA gene sequencing.

RESULTS

16 of 29 patients (55%) tested positive for either C. granulosa and or C. haemolytica. A total of 70 isolates (63 C. granulosa and 7 C. haemolytica) were cultivated from subgingival plaque. 15 (51%) patients tested positive for C. granulosa, and 3 (10%) patients tested positive for C. haemolytica.

CONCLUSION

This is the 1st report which recounts the presence of C. granulosa and C. haemolytica in subgingival plaque. Further research is required to establish the relative proportions of these species subgingivally in health and disease.

The clinical and microbiological effects of systemic ornidazole in sites with and without subgingival debridement in early-onset periodontitis patients

BACKGROUND

The purpose of this study was to evaluate the clinical and microbiological effects of systemic ornidazole (ORN) in sites with or without subgingival debridement in early-onset periodontitis (EOP) patients.

METHODS

Two pooled bacterial samples consisting of 4 sites each (scaled and non-scaled sites) were obtained from 30 individuals exhibiting EOP. All patients received oral hygiene instruction (OHI), supragingival scaling and ORN. Subgingival scaling and root planing (SRP) was carried out only in scaled sites. Bacterial samples were taken at baseline (BL) and 1 week and 2, 6, and 12 months after systemic ornidazole administration (500 mg/bid for 7 days). One more sample was taken at scaled sites, one week after SRP.

RESULTS

One week following SRP (scaled sites) Gram-negative facultative and anaerobic rods were significantly reduced while Gram-positive facultative cocci were significantly increased. After ORN administration, P. gingivalis, P. denticola, P. intermedia, B. forsythus, C. rectus, and S. sputigena were no longer detectable in either scaled or non-scaled sites. A statistically significant long-term (2, 6, and 12 months) reduction of P. gingivalis, P. intermedia, P. loescheii, B. forsythus, and C. rectus and a pronounced increase of S. milleri, S. oralis, and S. sanguis counts in both scaled and non-scaled sites were detected in comparison to baseline. A sustained reduction of bleeding tendency and of probing depth was also observed in both scaled and non-scaled sites.

CONCLUSIONS

ORN combined with SRP effects beneficial shifts in the bacterial population associated with substantial clinical improvement, thereby indicating that ORN is effective adjunct in the treatment of EOP deep periodontal pockets where anaerobic bacteria are predominant.

In vitro susceptibilities of Capnocytophaga isolates to beta-lactam antibiotics and beta-lactamase inhibitors

The susceptibilities of 43 pharyngeal isolates of Capnocytophaga to beta-lactam antibiotics, alone or in combination with beta-lactamase inhibitors, were tested by an agar dilution method. The 34 beta-lactamase-positive strains were highly resistant to beta-lactams, but the intrinsic activities of clavulanate, tazobactam, and sulbactam against Capnocytophaga, even beta-lactamase producers, indicates that these beta-lactamase inhibitors could be used for empirical treatment of neutropenic patients with oral sources of infection.

Measurement of peptidase activity and evaluation of effectiveness of administration of minocycline for treatment of dogs with periodontitis

OBJECTIVE

To determine clinical, enzymatic, and microbiologic effects of controlled-release localized administration of minocycline on dogs with periodontitis.

ANIMALS

Five adult Beagles with periodontitis.

PROCEDURE

After tooth scaling and root planing, 2 treatment, 1 placebo, and 1 control site were selected for each dog. Treatment sites (n = 10) received a periodontal formulation of minocycline hydrochloride, placebo sites (5) received ointment without minocycline, and control sites (5) did not receive ointment. Treatments were administered 4 times at weekly intervals. Peptidase activity and clinical and microbiologic effects were evaluated and compared among sites for 17 weeks.

RESULTS

Bleeding of the gums on probing (BOP) and pocket depth (PD) improved at the treatment site and were maintained for 13 weeks after treatment. However, BOP and PD in placebo and control sites increased from weeks 9 to 17 Peptidase activity in the periodontal pocket decreased noticeably from week 1 to 17, compared with baseline values for the treatment site. However, peptidase activity for placebo and control sites increased and were above baseline values on week 9 and week 13, respectively. Total bacterial counts decreased by 90% for treatment sites and remained at that value for 13 weeks. However, for placebo and control sites, bacterial counts increased and reached the baseline value on week 17.

CONCLUSIONS AND CLINICAL RELEVANCE

Increased peptidase activity is correlated with the progression of periodontitis in dogs. Treatment with minocycline, using a localized delivery system, was effective in dogs for at least 13 weeks after cessation of drug administration.

Profile of subgingival microbiota in children with mixed dentition

A diversity of microbial species has been detected in children's oral flora at an early age. To investigate the composition of the subgingival microbiota of different groups of teeth in children with mixed dentition, 40 systemically healthy children, aged 7-8 years, randomly chosen, were examined. Subgingival plaque samples were taken from the mesiobuccal sites of 21, 41, 16 and 36 permanent teeth and 53, 73, 64 and 84 deciduous teeth. The samples were cultured for bacterial isolation anaerobically and in 10% CO2 plus air using selective and nonselective media. Forty-five different microbial species were isolated from both permanent and deciduous teeth. Streptococcus sanguis (79-70%), Streptococcus mitis (66-65%), Prevotella melaninogenica (51-57%), Eikenella corrodens (51-52%), Capnocytophaga gingivalis (46-34%), Capnocytophaga ochracea (45-45%), Actinomyces naeslundii (39-60%) and Prevotella intermedia (42-35%) were among the most frequently detected species in permanent and deciduous teeth respectively. Several suspected periodontal pathogens, such as Porphyromonas gingivalis, Prevotella loescheii, Campylobacter gracilis, Bacteroides forsythus, Campylobacter concisus, Peptostreptococcus micros and Selenomonas sputigena, albeit less frequently detected, were present in the microbiota of these children. The bacterial species Streptococcus constellatus, Peptostreptococcus micros, Pseudoramibacter alactolyticus, E. corrodens and Fusobacterium nucleatum were associated with non-bleeding permanent and deciduous teeth whereas Streptococcus intermedius, C. concisus, P. intermedia and P. loescheii were associated with bleeding.

Characterization of an outer membrane protein gene, pgmA, and its gene product from Porphyromonas gingivalis

A gene upstream from fimA, the gene encoding fimbrilin, on the chromosome of Porphyromonas gingivalis was sequenced and shown to be the gene encoding an outer membrane protein in this organism based on homology and biochemical analyses. Therefore, the gene (formerly ORF5) was designated pgmA, the P. gingivalis outer membrane protein A gene. The gene product, PgmA, was sensitive to protease, and was detected as a 60-kDa protein from wild-type strains with trichloroacetic acid treatment, which was carried out to destroy intrinsic proteases, and from protease-deficient mutants without this treatment prior to electrophoresis. PgmA was indeed present in the membrane fraction. Its nature was determined to be that of outer membrane proteins in gram-negative bacteria based on attempts at differential extraction of inner membrane proteins with detergents. No evidence has been found thus far from functional analyses that this protein is related to fimbrial morphogenesis and functions or to serum resistance of this organism.

Induction of apoptosis in human gingival fibroblasts by a Porphyromonas gingivalis protease preparation

Proteases produced by Porphyromonas gingivalis are believed to contribute to the pathogenesis of periodontal diseases. Here the cytotoxic effects of a purified preparation of a P. gingivalis protease with trypsin-like specificity were tested on human gingival fibroblasts in vitro. The active protease induced apoptotic cell death in the fibroblasts, as indicated by DNA fragmentation and the expression of 7A6 antigen. Thus, the production of proteases by periodontopathic bacteria could be an important factor in the induction of apoptosis of host cells in the aetiology of periodontal diseases.

Restriction fragment-length polymorphism analysis of 16S ribosomal RNA genes amplified by polymerase chain reaction for rapid identification of cultivable oral treponemes

Although oral treponemes are among the most frequently found bacteria in periodontal pockets, identification of these organisms can be difficult. In this study, restriction fragment-length polymorphism (RFLP) analysis of polymerase chain reaction (PCR)-amplified 16S ribosomal RNA genes (16S rRNA gene PCR-RFLP) was used to generate restriction profiles of reference strains of oral treponemes including Treponema denticola, Treponema socranskii, Treponema vincentii. Treponema pectinovorum and Treponema medium as well as for Treponema phagedenis and Treponema pailidum and five treponeme strains isolated from human peridontal pockets. Before RFLP analysis, the 16S rRNA gene sequences were obtained from the GenBank database, and the analysis of the theoretical banding patterns for HpaII suggested good species discrimination. 16S rRNA gene sequences were amplified from isolated genomic DNA samples by PCR with spirochete-specific primers. The PCR products were then purified and characterized by single digestion with restriction endonuclease HpaII, and this allowed discrimination between the respective reference strains. Five clinical isolates, four T. denticola and one T. socranskii, were assigned on the basic of their restriction profiles by digestion with HpaII. 16S rRNA gene PCR-RFLP using HpaII is a rapid and reliable method for differentiation of cultivable oral treponemes.

Clinical and microbiological characteristics of smokers with early onset periodontitis

Cigarette smoking is a potential risk factor which has recently been associated with periodontal disease progression. The objective of this study was to compare the microbial profile of smokers and non-smokers in a group of patients with early onset periodontitis. The study population consisted of 60 healthy individuals, 40 males and 20 females aged 22 to 35 yr, exhibiting early onset periodontitis. Thirty patients were smokers (30.9 cigarettes/d) and 30 non-smokers. Smokers had a higher proportion of deep pockets (PD >5 mm), especially in the maxilla anterior and premolar regions (p < 0.001) and presented a significantly greater mean probing depth and attachment loss (p <0.05) in diseased sites and a significantly greater alveolar bone loss (p <0.01) compared to non-smokers. Two pooled bacterial samples were obtained from each patient. Samples were collected from the deepest periodontal pockets of each quadrant. The samples were cultured anaerobically and in 10% CO2 plus air for bacterial isolation using selective and non-selective media. Isolates were characterized to species level by conventional biochemical tests and various identification kits. Smokers harboured a greater number of bacteria in total. Analysis of bacterial counts using the ANOVA (Mann-Whitney U-test) showed that Staphylococcus aureus, Peptostreptococcus micros, Campylobacter concisus, Escherichia coli, Bacteroides forsythus, C. gracilis, C. rectus, Porphyromonas gingivalis, Selenomonas sputigena, Candida albicans and Aspergillus fumigatus were found in significantly higher numbers and more frequently in smokers while Streptococcus intermedius, A. naeslundii, A. israelii and Eubacterium lentum were detected more frequently and in significantly higher proportions in non-smokers. The isolation of bacteria belonging to the exogenous flora such as E. coli, C. albicans, A. fumigatus and S. aureus in smokers' microbiota underscores the importance of the host that is adversely affected by cigarette smoking.

Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in young Chinese adults

The aim of this study was to determine the presence or absence of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in young Chinese adults and to examine the A. actinomycetemcomitans isolates from positive subjects with regard to the serotype distribution, presence of the leukotoxin gene lktA and the promoter for the leukotoxin operon as well as the incidence of phage Aa phi 23. Sixty subjects, working in a knitting factory in the Province of Guangzhou, People's Republic of China, were investigated. Subgingival microbial samples were taken from both upper first molars. They were cultured both anaerobically and in 5% CO2. P. gingivalis was found in 33 subjects. On average, it constituted 7% of the total anaerobic cultivable counts. A. actinomycetemcomitans was detected in 37 subjects of which seven yielded counts > 10(5). Twenty-one subjects were positive for both organisms. A. actinomycetemcomitans serotype a was found in 9 subjects, serotype c was found in 23 and serotype e in 5. A. actinomycetemcomitans serotypes b and d were not detected in any subjects. Presence of the leukotoxin gene lktA was demonstrated for all A. actinomycetemcomitans isolates; however, none of the A. actinomycetemcomitans strains from the present study had a deletion in the promoter region of the leukotoxin operon. The results of this investigation show a high frequency of the putative periodontal pathogens P. gingivalis and A. actinomycetemcomitans and corroborate the concept that there is variation in virulence and pathogenic potential among isolates from different subjects.

Periodontal diagnosis: current status and future directions

It is of concern to both public health agencies and health professionals to know whether the prevalence of periodontal diseases is increasing or decreasing in the world today. Unfortunately, the answer does not appear to be that simple. Clinical signs of inflammation are unable to reliably distinguish between non-destructive forms of periodontal disease (gingivitis) and destructive forms (periodontitis). Physical assessments of damage to periodontal tissues, such as radiographic detection of bone loss or clinical attachment loss determined with a periodontal probe, measure damage from past episodes of destructive disease. New directions are needed to help to better diagnose periodontal diseases and some of the future possibilities are described and discussed.

Microbial factors and gingival crevicular fluid aspartate aminotransferase levels. A cross-sectional study

The aim of this cross-sectional study was to investigate the clinical application of chairside tests for gingival crevicular fluid (GCF) aspartate aminotransferase (AST) levels and plaque BANA hydrolysis activity with the presence of the periodontal pathogens Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans. The study comprised 100 periodontitis sites (pocket depths > or =4 mm, GI=3) from 10 patients with chronic adult periodontitis and 100 control sites (pocket depths <4 mm, GI<3) from 10 periodontally healthy patients comprising 55 healthy sites (pocket depths <4 mm, GI=0) and 45 gingivitis sites (pocket depths <4 mm, GI=1 or 2). The values for both BANA hydrolysis and AST levels were significantly higher in samples from periodontitis compared with gingivitis and healthy sites (p<0.001). A. actinomycetemcomitans was identified in 45% and P. gingivalis in 17% of periodontitis sites but neither pathogen was recovered from control sites and there was no significant correlation with the clinical parameters measured. There was no significant relationship between the presence of P. gingivalis and/or A. actinomycetemcomitans with BANA hydrolysis or AST levels. A significant correlation (p=0.0017) was observed between BANA hydrolysis and pocket depth and between AST hydrolysis and the GI (p=0.01). This study failed to demonstrate a positive association between chairside analysis of GCF metabolites for AST levels and/or BANA hydrolysis with P. gingivalis and A. actinomycetemcomitans. However, the GCF metabolites had a significant correlation with periodontally diseased sites in patients with chronic adult periodontitis and may help confirm clinical observations.

Virulence characteristics of oral treponemes in a murine model

This study was designed to investigate the virulence characteristics of Treponema denticola, T. socranskii, T. pectinovorum, and T. vincentii following challenge infection of mice. These microorganisms induced well-demarcated, dose-dependent, raised subcutaneous (s.c.) abscesses which were similar in time of onset, lesion progression, and duration of healing. Only viable cells were capable of inducing these characteristic s.c. abscesses. Histological examination of the skin lesion 3 and 5 days postinfection revealed abscess formation in the s.c. tissues, and abundant spiral organisms were demonstrated to be present in the abscess. Host resistance modulation by dexamethasone (neutrophil alteration) and cyclophosphamide (neutrophil depletion) pretreatment had a minimal effect on the virulence expression by any of these treponemes. The T. denticola isolates demonstrated significant trypsin-like protease (TLPase) activity, while both T. socranskii and T. vincentii were devoid of this activity. Interestingly, T. pectinovorum strains were heterogeneous with respect to TLPase as high producers, low producers, and nonproducers. However, no differences in lesion formation were noted regardless of whether the species expressed this proteolytic activity or whether treatment with N alpha-p-tosyl-L-lysine chloromethyl ketone (TLCK) and dithiothreitol was performed. These results showed that (i) a murine model may be used to evaluate virulence expression by oral treponemes; (ii) while TLPase activity varies among the oral treponemes, this protease does not appear to participate in abscess induction in the mouse model; and (iii) T. pectinovorum strains show variation in TLPase activity.

Comparison of the subgingival microbiota of periodontally healthy and diseased adults in northern Cameroon

Our study is the 1st report on subgingival microbiota in adult Cameronians. The aim was to investigate, using the checkerboard DNA-DNA hybridization technique, the prevalence of 18 oral species in subgingival plaque samples obtained from sex- and age-matched Cameronian adults with and without periodontal destruction. We also compared cultivation and the Affirm DP test with the checkerboard technique in their capability to detect some selected species among the 18. 21 adult periodontitis patients and 21 periodontally healthy subjects were examined and the results were compared statistically. Each periodontitis patient had at least 4 pockets of > or = 6 mm depth, while the healthy subjects had no sites more than 3 mm deep. Results of the checkerboard analysis showed that significantly (p < 0.05) more periodontitis patients tested positive for most of the 18 bacterial species. The Gram-positive species Actinomyces naeslundii, Streptococcus mitis and Streptococcus sanguis, known as microbiota of healthy sites, were detected significantly more frequently in the healthy group. Cultivation demonstrated P. gingivalis, B. forsythus, A. actinomycetemcomitans, P. intermedia and F. nucleatum in significantly lower %s of patients as compared to the checkerboard technique. Furthermore, the Affirm DP test detected P. gingivalis and B. forsythus in significantly fewer patients than did the checkerboard technique. A. actinomycetemcomitans was detected in 52.3% of the patients by the latter technique while the Affirm DP test failed to detect the bacterium in any of the samples. Overall, the results of the present study confirm the importance of the screening method and indicate that the prevalences of the investigated putative periodontal pathogens and beneficial species in the healthy and diseased adult Cameronians were similar to those reported for adults in the West and in some developing countries.

Loss of deciduous teeth and germs of permanent incisors in a 4-year-old child. An atypic prepubertal periodontitis? A clinical, microbiological, immunological and ultrastructural study

A 4-year-old child was referred, in April 1988, to Rennes Dental School (France) for deciduous tooth mobility with premature loss of 4 deciduous teeth and germs of 2 permanent incisors. Microbiological examinations by culture revealed the presence of the periodontal pathogen Actinobacillus actinomycetemcomitans. Immunofluorescence of plaque samples revealed the presence of Porphyromonas gingivalis that had not been isolated by culture. Neutrophil functions were within normal ranges. Transmission electron microscopy of gingiva showed a disorganised epithelium. The connective tissue was infiltrated by inflammatory cells. The basement membranes were normal, but the connective tissue-epithelium interface was mainly composed of short rete pegs. Scanning electron microscopy of extracted deciduous teeth revealed lack of cementum, lacunae in the cementum and lack of fibrillar insertion on the middle part of the root. Skin lesions, mainly situated on face, were observed. Treatment was by extraction of mobile deciduous teeth combined with 3-week courses of metronidazole. Clinical and microbiological follow-up was continued over a 7-year period. No periodontal lesions have been detected since eruption of the permanent teeth. The present subgingival and lingual microflora (December 1995) is composed of bacteria associated with periodontal health. However, the future appearance of a hitherto undetected systemic disease is still possible.

Characterization of protease activities in Capnocytophaga spp., Porphyromonas gingivalis, Prevotella spp., Treponema denticola and Actinobacillus actinomycetemcomitans

Protease activities in cell sonicates of defined bacterial strains were examined using peptide substrates and class-specific inhibitors. Capnocytophaga spp. all produced serine dipeptidyl peptidase activity and arginine/lysine, elastase- and chymotrypsin-like enzymes with some metalloprotease characteristics. The elastase-like activity was strongest in Capnocytophaga sputigena, but the others were greatest in Capnocytophaga gingivalis. The latter also had a separate arginine-specific enzyme which appeared not to be present in the other two species. Porphyromonas gingivalis showed serine dipeptidyl peptidase activity and very strong arginine and lysine cysteine protease activities. Prevotella spp. had inhibitor-resistant dipeptidyl peptidase activity and arginine cysteine protease activity that was much weaker but biochemically similar to P. gingivalis. Treponema denticola possessed a strong trypsin-like serine protease activity as well as very weak dipeptidyl peptidase and chymotrypsin-like activities that were sensitive to some cysteine protease reagents. Actinobacillus actinomycetemcomitans showed a novel alanine- and lysine-specific activity, but its nature was unclear.

In vitro effect of the Sensonic toothbrush on Treponema denticola

The purpose of this in vitro study was to compare the effects of the Sensonic. Oral-B Braun mechanical and Oral-B manual toothbrushes upon the morphology and cellular integrity of Treponema denticola. This spirochete was chosen because of its frequent isolation from active lesions of inflammatory periodontal disease and its pathogenic potential. T. denticola, strain ATCC 33421, was grown in an anaerobic nitrogen rich atmosphere in enhanced 1186 mycoplasma broth. 160, 5-ml aliquots of cultured microbes were assigned to 1 of 3 brushing treatment groups and a control group. Samples were further divided into 4 groups of 10 samples each and assigned to one of 4 brushing exposure times: 15, 30, 45, and 60 seconds. After treatment, 0.2 ml of each sample was applied to a millipore filter and examined by SEM. Intact microbes were counted from 10 non-overlapping fields at 4500x. Remaining treated samples were pelleted and examined by TEM. A statistically significant reduction of intact microbes for the Sensonic treatment group at each exposure time was found when compared to Oral-B Braun, Oral-B manual, and non-treated controls. TEM examination of Sensonic treated samples revealed separation of the outer membrane at lower exposure times and only cellular debris after exposures of 45 and 60 s. These results suggest that exposure to the sonic frequency generated by the Sensonic toothbrush is capable of severely disrupting the structural integrity of T. denticola.

Development of resistance to metronidazole and minocycline in vitro

By local delivery of antibiotics to periodontal pockets, very high initial concentrations are often quickly succeeded by subinhibitory concentrations, which may facilitate development of bacterial resistance. The purpose of the present study was to investigate possible development of resistance in suspected periodontal pathogens after exposure to subinhibitory concentrations of metronidazole and minocycline. The minimal inhibitory concentration (MIC) of 18 reference strains and 12 clinical isolates was determined by a broth dilution method. Subsequently, all strains with MIC < 8 micrograms/ml were exposed to serial passage on plates containing subinhibitory and gradually increasing concentrations of antibiotics, until growth was inhibited. Initially, most strains were inhibited at < or = 0.250 microgram/ml of minocycline and < or = 0.5 microgram/ml of metronidazole, though A. actinomycetemcomitans was resistant to metronidazole. After growth at subinhibitory concentrations, 8 strains survived 1-2 x and 11 stains survived 8-32 x their initial MIC of metronidazole, growing at up to 8 micrograms/ml. All A. actinomycetemcomitans survived 8-64 x their initial MIC of minocycline, growing at > or = 2 micrograms/ml, while all other strains were inhibited at < or = 0.250 microgram/ml, corresponding to a 1-8 x increase in their initial MIC. Thus, development of resistance was observed for periodontal bacteria growing at up to 64 x their initial MIC, but the final level of resistance was moderate.

Detection of neutral protease (Periocheck) and BANA hydrolase (Perioscan) compared with traditional clinical methods of diagnosis and monitoring of chronic inflammatory periodontal disease

Perioscan requires a plaque sample to detect the presence of enzymes capable of degrading N-benzoyl-DL-arginine-2-naphthylamide (BANA) from relatively few anaerobic periodontal pathogens. Periocheck assays the presence of neutral proteases in crevicular fluid. The aim of this study was to compare these test kits with traditional clinical methods of detecting periodontal disease and to monitor the ability of the kits to reflect the response to initial therapy. 19 patients with moderately severe chronic periodontitis were seen before and after a course of oral hygiene and root instrumentation consisting of 4 appointments. Clinical measurements and test assays were collected at 5 diseased sites and 2 healthy sites in each subject. Complete data from 125 sites were available for statistical analysis. At baseline Periocheck had a sensitivity of 88% and a specificity of 61% whereas Perioscan had a sensitivity of 99% and a specificity of 55%, when related to the clinical diagnosis. A composite clinical assessment, based on improvement or deterioration of one whole unit change of the subjective clinical indices and 2 mm changes or greater in probing depth or probing attachment level, revealed 75 sites which improved following treatment, whereas 45 sites did not change and 5 sites deteriorated. The probability that the tests agreed with the clinical outcome after treatment, was calculated as 50.4% for Periocheck and 52% for Perioscan. The diagnostic kits did not reliably reflect the clinical assessment of periodontal disease in the cross sectional study, or the outcome following treatment.

Periodontal disease diagnosis: current status and future developments

OBJECTIVES

This manuscript attempts to critically review traditional and currently employed methods of periodontal diagnosis, in the light of current knowledge about individual patients and sites at risk of progressive periodontal attachment loss.

DATA SOURCES

Articles published over the last decade from international research journals, have demonstrated that existing methods of periodontal disease diagnosis are seriously deficient with respect to accuracy, their ability to predict ongoing or future disease activity and their ability to determine the current activity status of historically diseased sites.

STUDY SELECTION

Longitudinal studies have questioned the rationale behind traditional treatment regimes and underlined the importance of site-directed therapy to avoid potentially damaging instrumentation of quiescent or healthy sites. The recent explosion in local, less invasive chemotherapies for periodontal disease management has aimed at addressing the site-specific nature of this group of diseases, but the true benefits of such novel therapies cannot be realised until more accurate and specific diagnostic techniques become available.

CONCLUSIONS

The manuscript concludes that the range of clinical information collected by experienced periodontists using currently available technology is probably sufficient to manage mild-to-moderate chronic adult periodontitis. However, those patients at risk from more aggressive attachment loss, and those individuals that appear refractory to traditional therapies, require the development of more accurate diagnostic tests to compliment the revolution in site-specific therapies. A diagnostic model is presented, which attempts to draw together current and future diagnostic methods for managing the majority of periodontal disease types, and it is suggested that current diagnoses should include some assessment of "risk'.

The relationship between microbial factors and gingival crevicular fluid glycosaminoglycans in human adult periodontitis

Counts of cultivable Porphyromonas gingivalis, assays of microbial proteases and the concentration in gingival crevicular fluid of proteoglycan metabolites were investigated at periodontitis and gingivitis sites in 16 patients with chronic adult periodontitis before and after treatment. Two periodontitis sites and two gingivitis sites were selected from each patient on the basis of a clinical examination. Gingival crevicular fluid from each site was analysed for the concentrations of the glycosaminoglycans chondroitin-4-sulphate and hyaluronan and subgingival plaque samples were analysed for cultivable P. gingivalis and microbial trypsin-like proteases assayed by benzoyl-DL-arginine-naphthylamide (BANA) hydrolysis. Significantly higher concentrations (p = 0.007) of chondroitin-4-sulphate were found at periodontitis than gingivitis sites but there was no significant difference in hyaluronan (p = 0.36) between these sites. Although the majority of periodontal sites were P. gingivalis-negative (23/32), there were significantly higher concentrations of chondroitin-4-sulphate (p = 0.05) and hyaluronan (p = 0.04) at the P. gingivalis-positive, compared to negative, periodontitis sites. At BANA-positive periodontitis sites there were also higher concentrations of chondroitin-4-sulphate (p = 0.0015) and hyaluronan (p = 0.0001) than at BANA-positive gingivitis sites. There was a significant decrease in concentrations of chondroitin-4-sulphate and hyaluronan at periodontitis sites after treatment. This study lends support to the hypothesis that P. gingivalis may be actively involved in the destruction of connective tissue components at culture-positive sites but shows that elevated concentrations of connective tissue breakdown products may occur in gingival crevicular fluid from periodontal sites where this organism is absent.