The predominant cultivable microbiota of the periodontal abscess

Quantitative investigation of the bacterial content of periodontal abscess samples by real-time PCR

OBJECTIVES

Periodontal abscesses, which are part of the acute periodontal disease group characterized by the destruction of periodontal tissue with deep periodontal pockets, bleeding on probing, suppuration, and localized pus accumulation, cause rapid destruction of tooth-supporting tissues. This study aimed to evaluate the microbial content of periodontal abscesses by specific and culture-independent qPCR.

METHODS

This study was conducted on 30 volunteers diagnosed with periodontal abscesses and presenting with complaints of localized pain, swelling, and tenderness in the gingiva. Genomic DNA was isolated from the samples taken. Escherichia coli bacteria were used for the standard curve created to calculate the prevalence of target bacteria in the total bacterial load. 16S rRNA Universal primers were used to assess the total bacterial load and prevalence. Bacterial counts were analyzed with Spearman's rank correlation coefficients (ρ) matrix.

RESULTS

From the analysis of Real-Time PCR, Porphyromonas gingivalis (30, 100%), Prevotella intermedia (30, 100%), and Fusobacterium nucleatum (30, 100%) were detected in all samples. Campylobacter rectus (29, 96.6%), Porphyromonas endodontalis (29, 96.6%), Tannerella forsythia (28, 93.3%), Filifactor alocis (28, 93.3%), and Actinomyces naeslundii (28, 93.3%) were also frequently detected.

CONCLUSIONS

Periodontal abscesses were found to be polymicrobial, and not only periodontal pathogens appeared to be associated with the development of periodontal abscesses. The presence, prevalence, and number of Porphyromonas endodontalis and Propionibacterium acnes in the contents of periodontal abscesses were determined for the first time in our study. Further studies are needed to better understand the roles of bacteria in periodontal disease, including abscesses.

Comparative 16S rRNA gene sequencing study of subgingival microbiota of healthy subjects and patients with periodontitis from four different countries

AIM

To investigate the differences between the subgingival microbiota of healthy subjects (HS) and periodontitis patients (PP) from four different countries through a metagenomic approach.

MATERIALS AND METHODS

Subgingival samples were obtained from subjects from four different countries. Microbial composition was analysed through high-throughput sequencing of the V3-V4 region of the 16S rRNA gene. The country of origin, diagnosis and clinical and demographic variables of the subjects were used to analyse the microbial profiles.

RESULTS

In total, 506 subgingival samples were analysed: 196 from HS and 310 from patients with periodontitis. Differences in richness, diversity and microbial composition were observed when comparing samples pertaining to different countries of origin and different subject diagnoses. Clinical variables, such as bleeding on probing, did not significantly affect the bacterial composition of the samples. A highly conserved core of microbiota associated with periodontitis was detected, while the microbiota associated with periodontally HS was much more diverse.

CONCLUSIONS

Periodontal diagnosis of the subjects was the main variable explaining the composition of the microbiota in the subgingival niche. Nevertheless, the country of origin also had a significant impact on the microbiota and is therefore an important factor to consider when describing subgingival bacterial communities.

NETs Are Double-Edged Swords with the Potential to Aggravate or Resolve Periodontal Inflammation

Periodontitis is a general term for diseases characterised by inflammatory destruction of tooth-supporting tissues, gradual destruction of the marginal periodontal ligament and resorption of alveolar bone. Early-onset periodontitis is due to disturbed neutrophil extracellular trap (NET) formation and clearance. Indeed, mutations that inactivate the cysteine proteases cathepsin C result in the massive periodontal damage seen in patients with deficient NET formation. In contrast, exaggerated NET formation due to polymorphonuclear neutrophil (PMN) hyper-responsiveness drives the pathology of late-onset periodontitis by damaging and ulcerating the gingival epithelium and retarding epithelial healing. Despite the gingival regeneration, periodontitis progression ends with almost complete loss of the periodontal ligament and subsequent tooth loss. Thus, NETs help to maintain periodontal health, and their dysregulation, either insufficiency or surplus, causes heavy periodontal pathology and edentulism.

Characterization and Antimicrobial Susceptibility of Pathogens Associated with Periodontal Abscess

Knowledge of microbial composition and antimicrobials' susceptibility to periodontal abscesses is vital for their successful treatment. The current study aims to provide a thorough overview of the clinical and microbial features of periodontal abscesses of the local community. The study was carried out at Rehman College of Dentistry, Peshawar, Pakistan between December 2019 to March 2020. Clinical measurements and microbial samples were collected from 45 subjects. Microbial samples were anaerobically cultured for the growth of selected bacterial species. E-test was used to assess the susceptibility of bacterial species grown from the patient samples to amoxicillin, azithromycin, metronidazole, and tetracycline. The majority of affected patients had preexisting chronic periodontitis. All abscesses clinically demonstrated bleeding on probing and suppuration. The periodontal abscess was most commonly associated with lower incisors and canines, followed by lower molars and then upper incisor and canine teeth. Fusobacterium spp. (73%) was the most frequently detected species followed by Prevotella intermedia/nigrescens (65%), Porphyromonas gingivalis (46%) and Aggregatibacter actinomycetemcomitans (24%). The detected clinical isolates of certain bacteria demonstrated resistance to all tested antibiotics except azithromycin. We conclude that Fusobacterium spp., P. intermedia/nigrescens, P. gingivalis, C. rectus, T. forsythia and A. actinomycetemcomitans are closely associated with periodontal abscess. Bacterial species associated with periodontal abscess demonstrated some level of antimicrobial resistance to amoxicillin, metronidazole and tetracycline while antibiotic resistance to azithromycin could not be demonstrated.

Microbiota in Human Periodontal Abscess Revealed by 16S rDNA Sequencing

Periodontal abscess is an oral infective disease caused by various kinds of bacteria. We aimed to characterize the microbiota composition of periodontal abscesses by metagenomic methods and compare it to that of the corresponding pocket and healthy gingival crevice to investigate the specific bacteria associated with this disease. Samples from abscess pus (AB), periodontal pocket coronally above the abscess (PO), and the gingival crevice of the periodontal healthy tooth were obtained from 20 periodontal abscess patients. Furthermore, healthy gingival crevice samples were obtained from 25 healthy individuals. Bacterial DNA was extracted and 16S rRNA gene fragments were sequenced to characterize the microbiota and determine taxonomic classification. The beta-diversity analysis results showed that the AB and PO groups had similar compositions. Porphyromonas gingivalis, Prevotella intermedia, and other Prevotella spp. were the predominant bacteria of human periodontal abscesses. The abundances of Filifactor alocis and Atopobium rimae were significantly higher in periodontal abscesses than in the periodontal pocket, suggesting their association with periodontal abscess formation. In conclusion, we characterized the microbiota in periodontal abscess and identified some species that are positively associated with this disease. This provides a better understanding of the components of periodontal abscesses, which will help facilitate the development of antibiotic therapy strategies.

Acute periodontal lesions

This review provides updates on acute conditions affecting the periodontal tissues, including abscesses in the periodontium, necrotizing periodontal diseases and other acute conditions that cause gingival lesions with acute presentation, such as infectious processes not associated with oral bacterial biofilms, mucocutaneous disorders and traumatic and allergic lesions. A periodontal abscess is clinically important because it is a relatively frequent dental emergency, it can compromise the periodontal prognosis of the affected tooth and bacteria within the abscess can spread and cause infections in other body sites. Different types of abscesses have been identified, mainly classified by their etiology, and there are clear differences between those affecting a pre-existing periodontal pocket and those affecting healthy sites. Therapy for this acute condition consists of drainage and tissue debridement, while an evaluation of the need for systemic antimicrobial therapy will be made for each case, based on local and systemic factors. The definitive treatment of the pre-existing condition should be accomplished after the acute phase is controlled. Necrotizing periodontal diseases present three typical clinical features: papilla necrosis, gingival bleeding and pain. Although the prevalence of these diseases is not high, their importance is clear because they represent the most severe conditions associated with the dental biofilm, with very rapid tissue destruction. In addition to bacteria, the etiology of necrotizing periodontal disease includes numerous factors that alter the host response and predispose to these diseases, namely HIV infection, malnutrition, stress or tobacco smoking. The treatment consists of superficial debridement, careful mechanical oral hygiene, rinsing with chlorhexidine and daily re-evaluation. Systemic antimicrobials may be used adjunctively in severe cases or in nonresponding conditions, being the first option metronidazole. Once the acute disease is under control, definitive treatment should be provided, including appropriate therapy for the pre-existing gingivitis or periodontitis. Among other acute conditions affecting the periodontal tissues, but not caused by the microorganisms present in oral biofilms, infectious diseases, mucocutaneous diseases and traumatic or allergic lesions can be listed. In most cases, the gingival involvement is not severe; however, these conditions are common and may prompt an emergency dental visit. These conditions may have the appearance of an erythematous lesion, which is sometimes erosive. Erosive lesions may be the direct result of trauma or a consequence of the breaking of vesicles and bullae. A proper differential diagnosis is important for adequate management of the case.

Common dental and periodontal diseases: evaluation and management

Physicians may encounter patients with dental and periodontal diseases in the context of outpatient medical practice. It is important for physicians to be aware of common dental and periodontal conditions and be able to assess for the presence and severity of these diseases. This article reviews common dental and periodontal conditions, their cardinal signs and symptoms, outpatient-setting assessment techniques, as well as common methods of treatment. Physicians detecting gross abnormalities on clinical examination should refer the patient to a dentist for further evaluation and management.

Learned and unlearned concepts in periodontal diagnostics: a 50-year perspective

In the past 50 years, conceptual changes in the field of periodontal diagnostics have paralleled those associated with a better scientific understanding of the full spectrum of processes that affect periodontal health and disease. Fifty years ago, concepts regarding the diagnosis of periodontal diseases followed the classical pathology paradigm. It was believed that the two basic forms of destructive periodontal disease were chronic inflammatory periodontitis and 'periodontosis'- a degenerative condition. In the subsequent 25 years it was shown that periodontosis was an infection. By 1987, major new concepts regarding the diagnosis and pathogenesis of periodontitis included: (i) all cases of untreated gingivitis do not inevitably progress to periodontitis; (ii) progression of untreated periodontitis is often episodic; (iii) some sites with untreated periodontitis do not progress; (iv) a rather small population of specific bacteria ('periodontal pathogens') appear to be the main etiologic agents of chronic inflammatory periodontitis; and (v) tissue damage in periodontitis is primarily caused by inflammatory and immunologic host responses to infecting agents. The concepts that were in place by 1987 are still largely intact in 2012. However, in the decades to come, it is likely that new information on the human microbiome will change our current concepts concerning the prevention, diagnosis and treatment of periodontal diseases.

Clinical and microbiological characterization of periodontal abscesses

BACKGROUND/AIM

The knowledge of clinical features, microbial composition and susceptibility to antimicrobials of periodontal abscesses has recently improved. This descriptive clinical and microbiological study provides more information on the characteristics of periodontal abscesses.

MATERIALS AND METHODS

Clinical parameters and subgingival samples were examined from 54 subjects presenting 60 periodontal abscesses. Samples were cultured for anaerobic and facultative bacteria, and data were expressed as frequency detection and mean proportion of isolation for microorganisms. Selected isolates of Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Prevotella intermedia/nigrescens were used to test susceptibility to amoxicillin, azithromycin, tetracycline and metronidazole. Statistical descriptive analysis was conducted.

RESULTS

Most periodontal abscesses were present in patients with ongoing Chronic Periodontitis. Bleeding on probing, tumefaction and suppuration were present in almost all abscesses. Affected teeth were lower anterior teeth, upper anterior teeth and lower molars. The subgingival microbiota was composed of periodontal pathogens such as Fusobacterium spp. (75%), P. intermedia/nigrescens (60%), P. gingivalis (51%) and A. actinomycetemcomitans (30%). Some periodontopathogens showed antimicrobial resistance to tetracycline, metronidazole and amoxicillin, but not to azithromycin.

CONCLUSIONS

Periodontal abscesses showed typical clinical features associated with untreated periodontitis, and the organisms identified were important periodontopathic bacteria. Rationale use of antibiotic adjunctive therapy in abscess treatment should be taken into account.

Etiology and pathogenesis of periodontal diseases

The two most prevalent and most investigated periodontal diseases are dental plaque-induced gingivitis and chronic periodontitis. The last 10 to 15 years have seen the emergence of several important new findings and concepts regarding the etiopathogenesis of periodontal diseases. These findings include the recognition of dental bacterial plaque as a biofilm, identification and characterization of genetic defects that predispose individuals to periodontitis, host-defense mechanisms implicated in periodontal tissue destruction, and the interaction of risk factors with host defenses and bacterial plaque. This article reviews current aspects of the etiology and pathogenesis of periodontal diseases.

Microbiological examination of infected dental root canals

OBJECTIVES

The aim of this study was to investigate the root canal microbiota of primary and secondary root-infected canals and the association of constituent species with specific endodontic signs and symptoms.

METHODS

Microbial samples were taken from 60 root canals, 41 with necrotic pulp tissues (primary infection) and 19 with failed endodontic treatment (secondary infection). Strict anaerobic techniques were used for serial dilution, plating, incubation and identification.

RESULTS

A total of 224 cultivable isolates were recovered belonging to 56 different bacterial species. Individual root canals yielded a maximum of 10 bacterial species. Of the bacterial isolates, 70% were either strict anaerobes or microphilic. The anaerobes most frequently isolated were: Peptostreptococcus micros (35%), Fusobacterium necrophorum (23.3%), Fusobacterium nucleatum (11.7%), Prevotella intermedia/nigrescens (16.7%), Porphyromonas gingivalis (6.7%) and Porphyromonas endodontalis (5%). The root canal microflora of untreated teeth with apical periodontitis was found to be mixed, comprising gram-negative and gram-positive and mostly anaerobic microorganisms and usually containing more than 3 species per canal. On the other hand, facultative anaerobic and gram-positive bacteria predominated in canals with failed endodontic treatment, which harbored 1-2 species per canal. Suggested relationships were found between anaerobes, especially gram-negatives, and the presence or history of pain, tenderness to percussion and swelling (P<0.05). In particular, associations were found between: a) pain (n=29) and P. micros (P<0.01), P. intermedia/nigrescens and Eubacterium spp. (both P<0.05); b) history of pain (n=31) and P. micros (P<0.01) Porphyromonas and Fusobacterium spp. (P<0.05); c) tenderness to percussion (n=29) and Porphyromonas spp. (P<0.01), Peptostreptococcus and Fusobacterium spp. (P<0.001); d) swelling (n=20) and Peptostreptococcus spp. (P<0.01), Porphyromonas and Enterococcus spp. (P<0.05); e) wet canals (n=33) and Porphyromonas and Fusobacterium spp. (P<0.05); f) purulent exudate (n=20) and Porphyromonas, Peptostreptococcus and Fusobacterium spp. (P<0.05); previous endodontic treatment and Enterococcus faecalis, Streptococcus spp., P. micros, F. necrophorum (P<0.05).

CONCLUSIONS

Our findings indicate potential complex interactions of species resulting in characteristic clinical pictures which cannot be achieved by individual species alone. They also indicate that the microbiota of primary infected canals with apical periodontitis differs in number and in species from the secondary infected canals by using the culture technique.

Human cytomegalovirus and Epstein-Barr virus type 1 in periodontal abscesses

OBJECTIVES

Recent studies have linked herpesviruses to severe types of periodontal disease, but no information exists on their relationship to periodontal abscesses. The present study determined the presence of human cytomegalovirus (HCMV) and Epstein-Barr virus type 1 (EBV-1) in periodontal abscesses and the effect of treatment on the subgingival occurrence of these viruses.

MATERIAL AND METHODS

Eighteen adults with periodontal abscesses participated in the study. Subgingival samples were collected from each patient with sterile curettes from an abscess-affected site and a healthy control site. HCMV and EBV-1 were identified by polymerase chain reaction at the time of the abscess and at 4 months after surgical and systemic doxycycline therapy.

RESULTS

HCMV was detected in 66.7% of periodontal abscess sites and in 5.6% of healthy sites (P=0.002). EBV-1 occurred in 72.2% of abscess sites but not in any healthy site (P<0.001). HCMV and EBV-1 co-infection was identified in 55.6% of the abscess sites. Posttreatment, HCMV and EBV-1 were not found in any study site.

CONCLUSIONS

HCMV and EBV-1 genomes are commonly found in periodontal abscesses. These data favor a model in which a herpesvirus infection of the periodontium impairs the host defense and serves as a platform for the entrance of bacterial pathogens into gingival tissue with subsequent risk of abscess development.

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.

Periodontal abscess

This review focuses on the classification of periodontal abscesses, which are localized purulent infections of periodontal tissues, and discusses their etiology and clinical characteristics.

Tooth loss due to periodontal abscess: a retrospective study

This retrospective study focused on the frequency of tooth loss due to periodontal abscess among 42 patients who were treated by a single clinician over a 5- to 29-year period. A total of 114 patients were selected from the active periodontal recall schedule of a single periodontist at The University of Iowa College of Dentistry. The criteria for inclusion in the study included having a history of moderate to advanced periodontitis, being on 3 to 6 month recall periodontal maintenance care, and completion of active periodontal therapy prior to October 1987. Other parameters evaluated were age; gender; number of teeth present and missing at the initial, reevaluation, and last periodontal recall visit; initial periodontal prognosis; furcation involvement; non-surgical and surgical periodontal therapy; and reasons for tooth loss. Patients were grouped according to the number of teeth lost following active periodontal treatment into well-maintained (0 to 3), downhill (4 to 9), and extreme downhill (10 to 23) groups. Forty-two of the 114 patients were identified as having one or more periodontal abscesses. A total of 109 teeth were affected by periodontal abscess of which 49 (45%) teeth were lost and 60 (55%) were successfully maintained over an average of 12.5 years (5 to 29 years). More furcated teeth were lost than nonfurcated teeth and teeth given a hopeless prognosis were lost more consistently than those given a questionable prognosis in all groups. The frequency of periodontal abscess and tooth loss per patient was greater in the downhill and extreme downhill response groups than the well-maintained group. This suggests that teeth with a history of periodontal abscess can be treated and maintained for several years.

Pathogenicity of Prevotella intermedia and Prevotella nigrescens isolates in a wound chamber model in rabbits

The pathogenicity of 14 isolates identified as Prevotella intermedia or Prevotella nigrescens by serogrouping using monoclonal antibodies was compared in a tissue cage model in rabbits. Seven strains from periodontal abscesses, 5 strains from deep periodontal pockets and 2 strains from gingivitis were tested in the animal model comprising 6 Teflon tissue cages implanted on the back each of 34 rabbits. A total of 10(5)-10(8) cells of P. intermedia or P. nigrescens strains were inoculated alone or together with either Actinobacillus actinomycetemcomitans or Streptococcus mitis. Five strains of Porphyromonas gingivalis were used as a reference. The infectivity was recorded as pus formation and log viable count in aspirated material for 3, 7 and 14 days. None of the Prevotella strains inoculated in monoculture survived more than 3 days, and they had no capacity to produce abscess. P. intermedia or P. nigrescens strains in combination with A. actinomycetemcomitans produced abscesses in 33-100% and with S. mitis in 42-100%. No difference in abscess formation or log viable count in samples after 14 days was recorded between serogroup I (P. intermedia) and serogroup II and III (P. nigrescens). The infectivity of P. intermedia or P. nigresceas strains did not differ whether they were isolated from periodontal abscess, periodontal pocket or gingivitis. P. intermedia and P. nigrescens strains produced abscesses in combination with a facultative anaerobic strain and appears to have a similar pathogenicity in the wound chamber model in rabbits.

Protein degradation by Prevotella intermedia and Actinomyces meyeri supports the growth of non-protein-cleaving oral bacteria in serum

The proteolytic activities of oral bacteria are thought to play an important role in the aetiology of dental abscesses. Bacteria-derived proteases may contribute to tissue destruction, and are likely to impair host defence by degrading immunoglobulins and complement. Degraded periodontal tissue and tissue fluid are likely to constitute essential sources of nutrients in the abscess. Tissue fluid, which is derived from serum, is rich in protein and poor in carbohydrate, suggesting that breakdown of protein and fermentation of amino acids is a crucial step to generate energy for growth of the microflora. The number of oral bacterial species that perform hydrolytic cleavage of protein into polypeptides, the first step in protein degradation, is relatively small compared to the large majority of peptidase-producing species. In this study, we therefore investigated the growth-promoting effect of proteinase-producing species like Prevotella intermedia and Actinomyces meyeri on the growth of some non-proteinase producing bacteria in mixed cultures. We used serum as a substitute for the supposed natural substrate of the abscess microflora. The breakdown of serum proteins was investigated using capillary electrophoresis. Poor growth was found in mono- and mixed cultures of non-proteinase producing species Eubacterium lentum, Fusobacterium nucleatum. Peptostreptococcus micros, and Streptococcus intermedius. The presence of P. intermedia in mixed cultures strongly enhanced growth of these 4 species, according to the hypothesis that the growth of the mixed cultures was peptide-limited. The enhanced growth of P. intermedia in pronase-digested serum indicated peptide-limited growth of this organism in serum, despite its production of proteinase. We found that growth of monocultures of Actinomyces meyeri was poor. In contrast, A. meyeri grew well in mixed cultures and its presence stimulated growth of F. nucleatum and P. micros, suggesting a synergistic relationship. The growth of mono- and mixed cultures was investigated using one representative strain of each species. Thus, there is a small risk of having selected unique strains. Proteinase inhibitors reduced the growth of Porphyromonas gingivalis, Prevotella nigrescens, and P. intermedia in trypticase peptone-yeast extract medium with, and without, IgG. Our study indicated that proteinase-producing organisms play a key role in mixed cultures of oral bacteria in human serum by providing polypeptides for growth. This may explain their association with dental abscesses.

Microbial flora in the acute phase of periodontitis and the effect of local administration of minocycline

Periodontitis, similar to other infectious diseases, is known to progress as chronic inflammation with recurrent acute phases. The purpose of this study was to clarify the microbiological composition of the acute phase and to compare the bacterial flora with that of comparable chronic periodontal pockets. We also evaluated the effect of application of minocycline gel locally on the change in the microflora in the acute pockets. Microbial flora from the subgingival pockets of 28 patients in the acute phase of periodontitis and of 12 patients in a comparable chronic phase as the control were investigated by various bacterial culture methods including TS blood agar and TSBV plates. Minocycline gel was applied to the acute periodontal pockets. Changes in the microbiological proportion and clinical parameters at one week after baseline examination were followed by dark-field analysis, culture method, and indirect immunofluorescence technique. Characteristic features of bacterial proportions in the acute site were observed as an increase in Bacteroides forsythus. The number of Porphyromonas gingivalis and black pigmented anaerobic rods also increased. Application of minocycline gel in the acute pocket without any debridement produced improvement in clinical symptoms at one week. Black-pigmented anaerobic rods, P. gingivalis, and B. forsythus decreased significantly at one week after the application. Results indicate that periodontopathic bacteria including B. forsythus and P. gingivalis were predominant in the acute phase of periodontitis and a locally delivered antibiotic may be effective as an alternative modality of treating the acute inflammation.

Associations of endodontic symptoms and signs with particular combinations of specific bacteria

Significant associations have been reported between (a) specific bacterial species isolated from root canals and (b) between individual bacterial species and endodontic symptoms and signs. The prime objective of this study was to determine whether particular combinations of specific bacteria are associated with individual endodontic symptoms and signs. Seventy root canals were investigated microbiologically taking care to maintain the viability of obligate anaerobes, which accounted for 64% of the total species isolated, including Peptostreptococcus micros, Prevotella melaninogenica, Prevotella oralis, Eubacterium aerofaciens, Eubacterium lentum, Fusobacterium nucleatum, Prevotella buccae and Prevotella intermedia. Significant associations were found between individual clinical features and the following pairs of species: (a) pain (37 cases) and Peptostreptococcus spp./Prevotella spp., Peptostreptococcus spp./Prevotella melaninogenica, Pstr. micros/Prev. melaninogenica (all P < 0.01); (b) swelling (23 cases) and Pstr. micros/Prevotella spp. (P < 0.01); (c) 'Wet' canal (57 cases) and Prevotella spp./Eubacterium spp. (P < 0.01), Peptostreptococcus spp./Eubacterium spp. (P < 0.05). Thus data from this investigation suggests that statistically significant associations exist between individual endodontic symptoms and signs and particular combinations of specific bacteria.

Effect of treatment on some periodontopathogens and their antibody levels in periodontal abscesses

Twenty patients suffering from abscess of periodontal origin were treated and followed clinically and microbiologically for 6 months. Microbiological examination was performed by culture technique. One deep and one shallow periodontal pocket in the same patient were examined concomitantly. Serum was collected and analyzed for specific antibody level using ELISA methodology. Treatment included supragingival scaling, drainage, and irrigation of the periodontal pocket with 0.85% sodium chloride and systemic tetracycline administration, 1 g per day for 2 weeks. At baseline, 90% of the abscesses harbored Porphyromonas gingivalis and/or Prevotella intermedia. After 6 months, abscess sites demonstrated a reduced probing depth, less bleeding on probing, and gain of attachment. Abscess sites showed no P. gingivalis and the proportion of P. intermedia was significantly reduced 6 months after treatment. In deep periodontal pockets a similar pattern was seen. Shallow pockets demonstrated few clinical signs of inflammation and the number of bacteria was generally low. Campylobacter rectus, Capnocytophaga spp, and Fusobacterium nucleatum were frequently seen in low numbers in most sites during the study period, while Actinobacillus actinomycetemcomitans was detected only in a few sites. The IgG levels in patient sera against antigens of homologous bacterial strains remained fairly constant for 6 months. The result of the present study indicates that P. gingivalis and P. intermedia are involved in periodontal abscess formation. Also, treatment where drainage is combined with tetracycline administration promotes healing and reattachment.

Black-pigmented gram-negative anaerobes in periodontitis

Black-pigmented Gram-negative anaerobes have been associated with periodontal disease and tooth loss since they were first isolated by Burdon in 1928. Porphyromonas gingivalis, which is usually not isolated from children, adolescents or adults with no periodontal breakdown, has been recognized as one of the most important periodontopathogens. Its presence is strongly correlated with deep periodontal pockets, which are assumed to be its main habitat. Correlations have been shown also with attachment loss, clinical inflammation and serum antibody levels, indicating an aetiological role in the periodontal disease. Their pathogenicity in animal models resembling periodontal disease is documented. They are frequently isolated from periodontal abscesses. The relationship between Prevotella intermedia and periodontal disease is not clear. It is frequently isolated from advanced periodontitis, often as the only black-pigmented Gram-negative anaerobic species; however, the prevalence in adults with no periodontal breakdown is high. It is found frequently in periodontal abscesses and in acute necrotizing and ulcerative gingivitis. Serogroup I is found predominantly in deep periodontal pockets, whereas all serogroups (I-III) are found in shallow pockets and gingivitis. No conclusive difference in pathogenicity between serogroups has been found. Pr. melaninogenica, Pr. denticola and Pr. loescheii are frequently found in the gingival crevice in preschool children and other age groups with gingivitis, but are seldom found in deep periodontal pockets.

Eikenella corrodens in human oral and non-oral infections: a review

There is substantial evidence in support of the existence of distinct clinical forms of human periodontal disease. Moreover, these different forms of periodontal disease may be associated with relatively distinct subgingival microflora, often involving microaerophilic or anaerobic Gram-negative bacterial species. Eikenella corrodens is a facultative Gram-negative bacillus which is a common inhabitant of the oral cavity and the intestinal and genital tracts. Its primary ecologic niche within the oral cavity appears to be dental plaque, both in periodontally healthy individuals and in periodontitis patients. However, E. corrodens is recognized as an infrequent human pathogen capable of causing extraoral infections, either as the sole infectious agent or as part of a mixed infection, its potential role in the etiology of periodontal disease is not well understood. E. corrodens is often present in the supra- and subgingival plaque of periodontally healthy subjects. On the basis of cross-sectional and longitudinal studies, E. corrodens appears to be somewhat more prevalent in subgingival plaque samples of periodontitis subjects than periodontally healthy individuals. However, the percentage of E. corrodens in the total cultivable microflora did not vary between the two groups. Microbiologic studies attempting to define the relationship between E. corrodens and periodontal disease assume that this species is essentially homogeneous and that all strains exhibit comparable pathogenic potential. However, E. corrodens exhibits 1) variable colony morphology, biochemical and serologic reactivity; 2) marked phenotypic diversity with respect to outer membrane protein and lipopolysaccharide structure; and 3) marked diversity in the restriction patterns of total genomic DNA. Thus, it is possible that a limited number of clones of E. corrodens may be associated with periodontal disease and/or extraoral infection, while other strains are relatively harmless commensals. Additional studies, possibly employing strain-specific nucleic acid probes, may be required to define the role of E. corrodens as a human periodontal pathogen.

Serum antibody responses in human periodontitis to cellular components of Capnocytophaga

Serum levels of IgM, IgG and IgG-antibody subclasses directed against cell envelopes, lipopolysaccharides and cytoplasmic fractions from Capnocytophaga sputigena, C. gingivalis and C. ochracea were examined in age-, race- and sex-matched periodontally healthy (n = 25) subjects and subjects with adult periodontitis (n = 25). The envelopes and cytoplasmic fractions were obtained by ballistic disintegration of the cells and ultracentrifugation. Cell envelopes were treated with DNase, RNase and lysozyme. Lipopolysaccharides were obtained by hot phenol-water extraction and treated with DNase and RNase. The relative levels of the antibodies in response to the cell fractions were measured by the streptavidinbiotin micro enzyme-linked immunosorbent assay. Both groups showed IgM and IgG antibodies to each fraction of the three Capnocytophaga species, but the frequency of positive IgG subclass responses varied. The IgG4 responses were lower than the other subclasses. There were no significant differences between the IgM antibody levels of the two groups. However, the adult periodontitis group had significantly lower IgG antibody titres to the cell envelopes and cytoplasmic fractions of C. gingivalis and C. ochracea, and lipopolysaccharide of C. gingivalis. These results were reflected in the depressed levels of IgG1 and/or IgG2 to these cellular fractions from the same bacterial species. The adult periodontitis group also showed a lower level of IgG1 to the cytoplasmic fractions of C. sputigena without any depression in the total IgG antibody level. There were no significant differences between the groups in IgG3 and IgG4 antibody levels to any of the cellular fractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Peptostreptococcus micros in human periodontitis

Peptostreptococcus micros is a recognized pathogen in medical infections, and its association with progressive periodontitis was examined in this study. P. micros was isolated from paper-point subgingival samples on anaerobic enriched blood agar plates and identified on the basis of cellular and colonial morphology and selected biochemical tests. In a cross-sectional study involving 907 people with advanced adult periodontitis, 127 with early-onset periodontitis, and 12 with localized juvenile periodontitis, P. micros in these patient groups occurred with a prevalence of 58-63%. In culture-positive patients, P. micros averaged 12-15% of total viable counts. P. micros demonstrated similar occurrence and proportional recovery in all age groups. In a longitudinal study of 91 adult periodontitis patients on maintenance therapy, P. micros demonstrated a significantly higher prevalence in disease-active than in disease-inactive patients (47% vs 14%). Mechanical subgingival debridement and 0.12% chlorhexidine pocket irrigation was unable to eradicate subgingival P. micros from 18 of 22 adult periodontitis patients. In vitro antimicrobial susceptibility testing showed P. micros to be sensitive to therapeutic levels of penicillin, clindamycin and metronidazole. Our findings indicate that P. micros is a potential pathogen in adult periodontitis. The methods for its eradication from subgingival sites remain to be determined.

Predominant cultivable flora in pericoronitis

The predominant cultivable flora in pericoronitis was investigated by culturing pus from affected sites in 20 patients. Twenty colonies were picked at random from non-selective plates and identified using conventional biochemical and physiological tests, analysis of metabolic end-products by gas chromatography and protein profile analysis. The most frequently isolated organisms were Prevotella (Bacteroides) intermedia, Peptostreptococcus micros, Veillonella species, Fusobacterium nucleatum and Streptococcus mitis. Porphyromonas (Bacteroides) gingivalis was not isolated and asaccharolytic Eubacterium species were virtually absent. The predominant cultivable microflora in pericoronitis was found to be highly anaerobic in nature and superficially similar to that found in chronic periodontitis, although proposed marker organisms of severe periodontitis were absent.

Gingival enhancement in fixed prosthodontics. Part II: Microbiologic findings

This study assessed the changes of the subgingival/marginal microflora during fixed prosthodontic procedures and evaluated the effect of adjunctive rinsing with 0.12% chlorhexidine on the subgingival/marginal microflora during fixed prosthodontic treatment. Thirty patients scheduled for fixed prosthodontics were randomly assigned to either rinsing with 15 ml of tap water b.i.d. (control) or rinsing with 15 ml of 0.12% chlorhexidine gluconate b.i.d. (experimental). Subgingival and marginal plaque was analyzed at baseline, before crown preparation (2 weeks), before crown cementation (5 weeks), and 2 weeks after cementation (7 weeks). The fixed prosthodontic procedures alone altered the subgingival and marginal microbiota toward a more health-associated flora. Adjunctive rinsing twice daily with 0.12% chlorhexidine had a significantly greater effect in reducing putative periodontal pathogens compared with the control regimen. This medication was a useful adjunct to regular oral hygiene during fixed prosthodontic procedures by permitting the establishment and maintenance of a microflora compatible with periodontal health.

The prevalence of beta-lactamase producing bacteria in subgingival plaque and their sensitivity to Augmentin

Subgingival plaque samples from 20 patients with chronic periodontitis who had received no antibiotics for at least 3 months were screened for the presence of beta-lactamase-producing bacteria. Thirteen of the patients harboured beta-lactamase producing bacteria, most of which were members of the genus Bacteroides. The most frequently isolated species were Bacteroides melaninogenicus and Bacteroides capillosus which are often implicated in acute oral infections. All of the beta-lactamase-producing bacteroides strains were sensitive to a combination of amoxycillin with clavulanic acid (Augmentin).

Multiple periodontal abscesses after systemic antibiotic therapy

Multiple periodontal abscesses were reported in medically compromised patients. We examined patients with a non-contributory medical history referred for the treatment of numerous periodontal abscesses. All patients had taken oral broad spectrum antibiotics 1 to 3 weeks prior to the outburst of the abscesses (8 patients: penicillin, 2 patients: tetracycline). The patients suffered from advanced periodontal disease, 82% of the examined sites showed probing depths greater than 3 mm, 56% attachment loss greater than 3 mm. Subgingival plaque samples were analysed from 2 different abscess sites. Bacteroides gingivalis (19/20), Fusobacterium nucleatum (13/20) and Streptococcus intermedius (13/20) were the most prevalent anaerobic microbiota. Strains resistant to the prescribed antibiotic were found in 55% (11/20) of the subgingival plaque samples. It was concluded that in patients with advanced periodontal disease, systemic antibiotic therapy without subgingival debridement may change the composition of the subgingival microbiota, thus favouring the outburst of multiple periodontal abscesses.

Osteomyelitis associated with chronic periodontitis: a report of three cases

Correctly differentiating between periodontal abscess (localized, acute suppurative infection of the periodontium) and osteomyelitis (the extension of an infection into the bone medullary cavity) is crucial since the former may not require antibiotics for resolution, while the latter will. Initial assessment and treatment of osteomyelitis should be based on clinical examination, radiographic interpretation, and experience. Three case histories of osteomyelitis are presented, ranging from a periodontally well-localized case to one involving a hemimandible and crossing the midline. Successful early diagnosis and case management may benefit from scintigraphic interpretation and culture-and-sensitivity studies.

The role of black-pigmented Bacteroides in human oral infections

Today, 10 black-pigmented Bacteroides (BPB) species are recognized. The majority of these species can be isolated from the oral cavity. BPB species are involved in anaerobic infections of oral and non-oral sites. In the oral cavity, BPB species are associated with gingivitis, periodontitis, endodontal infections and odontogenic abscesses. Cultural studies suggest a specific role of the various BPB species in the different types of infection. Bacteroides gingivalis is closely correlated with destructive periodontitis in adults as well as in juveniles. Bacteroides intermedius seems to be less specific since it is found in gingivitis, periodontitis, endodontal infections and odontogenic abscesses. The recently described Bacteroides endodontalis is closely associated with endodontal infections and odontogenic abscesses of endodontal origin. There are indications that these periodontopathic BPB species are only present in the oral cavity of subjects suffering from periodontal breakdown, being absent on the mucosal surfaces of subjects without periodontal breakdown. BPB species associated with healthy oral conditions are Bacteroides melaninogenicus, Bacteroides denticola and Bacteroides loescheii. There are indications that these BPB species are part of the normal indigenous oral microflora. Many studies in the past have documented the pathogenic potential and virulence of BPB species. This virulence can be explained by the large numbers of virulence factors demonstrated in this group of micro-organisms. Among others, the proteolytic activity seems to be one of the most important features. Several artificial substrates as well as numerous biological proteins are degraded. These include anti-inflammatory proteins such as alpha-2-macroglobulin, alpha-1-antitrypsin, C3 and C5 complement factors and immunoglobulins. B. gingivalis is by far the most proteolytic species, followed by B. endodontalis. Like other bacteria, the lipopolysaccharide of B. gingivalis has shown to be active in bone resorption in vitro and is capable in stimulating interleukin-1 production in human peripheral monocytes. Based on the well documented association with periodontal disease and the possession of relevant virulence factors, BPB species must be considered as important micro-organisms in the etiology of oral infections. B. gingivalis seems to be the most pathogenic and virulent species.

A comparison of the reactivity of Eubacterium species with localized and serum immunoglobulins from rapidly progressive and adult periodontitis patients

Immunoglobulins in sera and in supernatant fluids of explant cultures of diseased gingival tissues from 20 rapidly progressive and 20 adult periodontitis sites were tested by an ELISA assay for reactivity with typed strains of Eubacterium alactolyticum, E. brachy, E. limosum and E. nodatum. Immunoglobulins present in tissue culture fluids from both rapidly progressive and adult periodontitis samples reactive with E. brachy and E. nodatum were significantly greater (P less than 0.05) than those reactive with E. alactolyticum or E. limosum. The titers to E. brachy in tissue culture fluids from adult periodontitis were significantly greater (P less than 0.05) than those from rapidly progressive periodontitis; there was no difference in titers to the other three species. The only significant difference in serum titers was that sera from patients with rapidly progressive periodontitis had significantly greater reactivity to E. alactolyticum than did sera from adult periodontitis patients. These data indicate that immunoglobulins in the sera of rapidly progressive and adult periodontitis patients do not necessarily reflect the reactivity of localized immunoglobulins present in the diseased gingival tissue explant culture fluids from these patients.

A study of the association of fraenal attachment, lip coverage, and vestibular depth with plaque and gingivitis

The effects of fraenal attachment, upper lip coverage, and mandibular vestibular depth on plaque and bleeding indices in the maxillary and mandibular anterior segments were studied in a group of 1015 school children aged 11.5 to 12.5 years. The position of the mandibular labial fraenum was relatively unimportant to plaque and mandibular gingivitis, but anterior fraenal attachment in the maxilla appeared to affect the retention of plaque and the degree of gingivitis. Maxillary and mandibular plaque and bleeding scores increased with decreasing upper lip coverage at rest. In the mandibular anterior segment, plaque and bleeding indices decreased with increasing vestibular depth. Further analysis demonstrated that fraenal attachment and vestibular depth and fraenal attachment and lip coverage were significantly associated. However, two-way analysis of variance indicated that the influence of fraenal attachment, vestibular depth, and lip coverage on plaque and gingivitis was independent. The influences of these soft tissue variables on plaque accumulation and gingivitis were of small clinical significance and not in themselves a justification for mucogingival surgery.

Microbial populations and active tissue destruction in experimental periodontitis

Although specific subgingival microflora are being associated with active tissue destruction in periodontitis, little information exists on the relationship between subgingival flora and histological evidence of tissue destruction. The present study was undertaken to explore these relationships during experimental marginal periodontitis in squirrel monkeys. In 4 squirrel monkeys, experimental periodontitis was induced around bicuspids and molars using silk ligatures. The buccal part of the subgingival ligature was removed for bacterial sampling 3, 7, and 14 days after ligature placement. Dark-field microscopy was used to quantify motile forms, spirochetes, straight and curved rods, filaments, cocci and fusiforms. Subgingival plaque prior to periodontitis induction was dominated by cocci, but fusiforms and straight rods were also present. Spirochetes, filaments, curved rods and motile forms were absent. 3 days after induction of periodontitis, there were marked increases in spirochetes, motile forms, filaments, curved and straight rods. The proportions of coccoids and fusiforms decreased. The bacterial proportions stayed at approximately the same levels through 7 and 14 days. Histometric quantification of periodontal destruction showed loss of connective tissue attachment and crestal alveolar bone. A positive correlation was found between periodontal tissue destruction and both total number of subgingival bacteria and spirochetes.

Bacteroides endodontalis and other black-pigmented Bacteroides species in odontogenic abscesses

Twenty-eight odontogenic abscesses were examined for the presence of black-pigmented Bacteroides spp. Of the 28 samples, 26 were found to contain one or more species of black-pigmented Bacteroides. Abscesses were divided into three categories according to the tissue of origin: endodontal, periodontal, and pericoronal. Four abscesses which developed after extraction were also examined. It was found that Bacteroides endodontalis, a newly described species of asaccharolytic black-pigmented Bacteroides, was isolated almost exclusively from periapical abscesses of endodontal origin. B. intermedius proved to be the most frequently isolated species in all of the samples. B. gingivalis was present in all of the periodontal abscesses studied, as well as in two endodontal abscesses. B. melaninogenicus was recovered once from a pericoronal abscess. Precautions for the isolation of B. endodontalis are discussed.

Oral colonization and susceptibility testing of Pseudomonas aeruginosa oral isolates from cystic fibrosis patients

Microbial samples from the oral cavities of cystic fibrosis (C.F.) patients and 20 age-matched normal control subjects were characterized. Mucoid variant Pseudomonas aeruginosa was isolated from the tongue, buccal mucosa, and saliva of C.F. patients only. Analysis of the data suggests that the oral cavity is a potential reservoir for this organism. Aspiration and cross-contamination from this reservoir may be important in perpetuating chronic pulmonary infection in C.F. patients. Susceptibility testing was performed on 20 mucoid variant P. aeruginosa oral isolates obtained from the patients according to standardized broth dilution procedures. The in vitro antimicrobial effects of sodium fluoride, stannous fluoride, and chlorhexidine were measured. Analysis of the data suggests that clinically safe and achievable levels of chlorhexidine and stannous fluoride may be antimicrobial.

Serum and salivary IgG and IgA response to initial preparation therapy

The purpose of this study was to determine and compare IgG and IgA concentration in both serum and unstimulated whole saliva obtained prior to any therapy and following initial preparation therapy (IPT) in 15 healthy adult dentulous patients, five each of periodontal disease Classes I, II and III. During the first visit before therapy, 10 ml of whole blood and 5 ml of saliva were obtained. Serum protein electrophoresis was conducted to rule out immunoglobulinopathies. Radial cell immunodiffusion endpoint technique was employed on serum and saliva to determine IgG and IgA in mg/dl. Following IPT, achievement of plaque control and 3 weeks after any dental instrumentation, 10 ml of blood and 5 ml of saliva were obtained from each patient and IgG and IgA in mg/dl were determined. The following are trends that were observed: greater decrease in IgG and IgA in serum and saliva following IPT in Class I periodontal patients than in other classes; saliva was a better indicator of local humoral response than serum for this group of patients; the less severe the periodontal involvement, more consistent was the reduction in IgG and IgA following IPT, especially for saliva; IPT elicited a decreased IgG and IgA concentration when local antigenic stimuli were reduced by both patient and dentist.