Actinobacillus actinomycetemcomitans, Capnocytophaga and Porphyromonas gingivalis in subgingival plaque of adolescents with Down''s syndrome

Levels of Actinobacillus actinomycetemcomitans, Capnocytophaga and Porphyromonas gingivalis were determined in subgingival plaque samples from 37 adolescents with Down's syndrome and 37 healthy controls matched with respect to age and sex. Gingival inflammation, supra- and subgingival calculus, periodontal pockets ( > 4 mm) and alveolar bone loss were registered. Alveolar bone loss was more frequent in Down's syndrome subjects (32%) than in the controls (3%). A. actinomycetemcomitans was detected in the subgingival plaque in 35% of the Down's syndrome adolescents and in 5% of the controls. On site level, A. actinomycetemcomitans and Capnocytophaga were more frequent in the subgingival plaque samples of Down's syndrome children than in those of controls. Comparing Down's syndrome subjects positive or negative for A. actinomycetemcomitans and Capnocytophaga, no significant differences were found in terms of gingival inflammation, periodontal pockets ( > 4 mm) or number of sites with alveolar bone loss. The results indicate an altered microbial composition of the subgingival plaque of Down's syndrome subjects compared with healthy controls, with higher frequency of A. actinomycetemcomitans.     

Langerhans' cell histiocytosis in a 5-year-old girl: evidence of periodontal pathogens

BACKGROUND: Langerhans' cell histiocytosis (LCH) is a rare disorder characterized by Langerhans' cell proliferation in various organs or tissues. When periodontal tissue is involved, clinical manifestations can vary from gingival recession and pocket formation to severe alveolar bone loss. This case report describes periodontal pathogens found in the pockets of involved primary teeth. METHODS: A 5-year-old girl with LCH presented with loose teeth. Intraoral examination and radiographs revealed deep pockets and severe bone loss around all primary molars. Bacterial samples were obtained from saliva and subgingival plaque and analyzed for the presence of five periodontopathic bacteria using a polymerase chain reaction (PCR) method. Due to severe periodontal destruction, all primary molars were extracted, and a gingival biopsy was taken from tooth T to confirm the diagnosis of LCH. RESULTS: The biopsy specimen revealed the histologic features of LCH. The patient was diagnosed as having periodontitis as a manifestation of LCH. PCR results of subgingival plaque from LCH-affected molars indicated the presence of Porphyromonas gingivalis, Tannerella forsythensis, Treponema denticola, and Prevotella intermedia. However, Actinobacillus actinomycetemcomitans was absent from these teeth. No tested bacteria were found in the non-affected anterior teeth. CONCLUSIONS: The bacteria commonly associated with periodontal disease were detected in subgingival plaque samples from this LCH patient. More microbiological data are required to understand the role of these bacteria in LCH-associated periodontal destruction.     

Immunological assays for putative periodontal pathogens

Immunological tests including immunofluorescence microscopy, latex agglutination, flow cytometry, and enzyme-linked immunosorbent assays are being developed for the detection of carcinogenic microorganisms and periodontal pathogens. In the present study, indirect immunofluorescence microscopy was used to examine two hundred eighty-three subjects for Actinobacillus ("Haemophilus") actinomycetemcomitans and Bacteroides gingivalis in subgingival dental plaque samples pooled from the mesial surface of the four first molar teeth. Alveolar bone height on panoramic radiographs was measured at each sample site using a Schei ruler and correlated with the results of immunofluorescence microscopy. Over ninety percent of the subjects did not demonstrate either putative periodonlal pathogen or harbored only trace amounts. Only 5% of the subjects demonstrated 2% or greater A. actinomycclemcomitans and no subject harbored more than 5% consistent with the finding that there were no localized juvenile periodontitis patients in this subject group. Nine percent of the subjects revealed 2% or more, and 5% demonstrated 5% or more of the total cell count as B. gingivalis. K. gingivalis levels , however, did exhibit a significant positive correlation with loss of alveolar bone height. The use of immunofluorescence microscopy for B. gingivalis exhibited 19% sensitivity, 96% specificity, 69% positive predictive value, and 69% negative predictive value when correlated with alveolar bone height measurements. The present data indicate that indirect immunofluorescence microscopy is a useful, rapid method for the detection of A. actinomycetemcomitans and B. gingivalis in subgingival dental plaque which can be used in the clinical diagnosis, treatment, and monitoring of periodontal disease. The sensitivity of microbiological assays as indicators of periodontal disease can likely be increased by utilization of additional Immunological tests for other putative periodontal pathogens.     

Detection of Actinobacillus actinomycetemcomitans and Bacteroides gingivalis in subgingival smears by the indirect fluorescent-antibody technique

An indirect immunofluorescence technique for the detection of Actinobacillus actinomycetemcomitans ( A. actinomycetemcomitans ) and Bacteroides gingivalis ( B. gingivalis ) in smears of subgingival plaque was evaluated. The assay used species-specific rabbit antibodies against A. actinomycetemcomitans (3 serotypes) and B. gingivalis (1 serotype) and a goat anti-rabbit IgG fluorescein conjugate. Of 88 periodontal specimens studied, about 80% were either positive or negative for the two species by both culture and immunofluorescence, about 5% revealed the organisms by culture but not by immunofluorescence, and about 13% were culture-negative and immunofluorescence-positive. In positive lesions, immunofluorescence tended to yield higher A. actinomycetemcomitans counts than culture and culture tended to yield higher B. gingivalis counts than immunofluorescence. In a periodontal treatment study including 21 adult patients and 73 deep periodontal pockets, A. actinomycetemcomitans or B. gingivalis were detected by immunofluorescence in 5 of 8 periodontal lesions which showed loss of probing periodontal attachment after therapy but not in any of 37 treated periodontal sites exhibiting probing attachment gain. It was concluded that indirect immunofluorescence can detect A. actinomycetemcomitans and B. gingivalis in subgingival plaque and that monitoring these organisms may aid in differentiating progressing and nonprogressing periodontitis lesions.     

Comparison of polymerase chain reaction and culture methods for detection of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in subgingival plaque samples

In this study, the major periodontal pathogens Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were detected in subgingival plaque samples from patients with periodontal disease by polymerase chain reaction (PCR) and conventional culture methods. 170 plaque samples from 43 patients were analysed; A. actinomycetemcomitans and P. gingivalis were each detected in 40 (24%) of samples by PCR. whereas conventional culture methods detected A. actinomycetemcomitans and P. gingivalis in 25 (15%) and 18 (11%) of samples, respectively. The proportion of patients carrying A. actinomycetemcomitans in at least 1 sampled periodontal site was 17/43 (40%) by PCR and 13/43 (30%) by culture; for P. gingivalis this was 2/43 (28%) by PCR and 9/43 (21%) by culture. Only 5 samples, from 3 patients, harboured both A. actinomycetemcomitans and P. gingivalis . It is concluded that PCR is more accurate than conventional culture methods for identification of these periodontal pathogens in subgingival plaque samples and has a higher frequency of detection.     

Localized aggressive periodontitis in primary dentition: a case report

BACKGROUND: A 5-year-old Japanese boy presented with persistent gingival inflammation and severe mobility of the right lower primary incisors. Due to severe alveolar bone loss and a deep periodontal pocket (5 mm), the incisors were extracted at the second visit. METHODS: Clinical, radiographic, histological, and microbiological examinations were carried out. Then, the polymerase chain reaction (PCR) technique was employed to detect specific periodontal pathogens. The chemotactic activity of polymorphonuclear neutrophils was also measured. RESULTS: Tannerella, Capnocytophaga, Fusobacterium, and Eikenella sp. were recovered from the subgingival microflora around the right lower incisors, while A. actinomycetemcomitans, Tannerella forsythensis (formerly Bacteroides forsythus), Prevotella nigrescens, Campylobacter rectus, and Capnocytophaga gingivalis were detected using the PCR method. Further chemotaxis assay revealed that neutrophil function was depressed compared with that of healthy controls. CONCLUSIONS: Although inflammation remained around the right primary second molars, the bone loss was controlled by periodic professional mechanical teeth cleaning (PMTC), subgingival irrigation, and local antibiotic application. The probing depths of all teeth, including permanent incisors and molars, were within 2.5 mm.     

Microbiologic analysis of periodontal pockets and carotid atheromatous plaques in advanced chronic periodontitis patients

BACKGROUND: In recent years, many researchers have focused their attention on the ability of periodontal pathogens to colonize atheromatous plaques. Nevertheless, a clear correlation between the detection rates of periodontopathic bacterial DNA in atheromas and in subgingival plaque samples has not been established. The aim of our study was to assess the presence of five periodontal pathogens (Actinobacillus actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia [formerly Tannerella forsythensis]) in periodontal pockets and in carotid atheromas recovered from the same patients. METHODS: Thirty-three patients with advanced chronic periodontitis scheduled for endarterectomy were enrolled in the study. DNA was extracted from subgingival plaque samples and carotid atheromas. Universal bacteria primers for general detection of bacteria and species-specific primers for detection of periodontal pathogens were used to amplify part of the 16S rRNA gene by polymerase chain reaction. RESULTS: All subgingival plaque samples were positive for at least one target microorganism. The prevalence of T. forsythia, P. gingivalis, T. denticola, P. intermedia, and A. actinomycetemcomitans were 69.7%, 63.6%, 54.5%, 45.4%, and 33.3%, respectively. Bacterial DNA was detected in 31 out of 33 endarterectomy specimens. However, none of the samples tested positive for DNA from periodontal pathogens. CONCLUSION: The presence of periodontal bacteria in atheromatous plaques was not confirmed by this investigation; thus, no correlation could be drawn between periodontitis bacteria and microorganisms involved in the atherosclerotic lesions.     

Actinobacillus actinomycetemcomitans and clinical periodontal status in Finnish juvenile periodontitis patients

The relationship between the clinical periodontal status and the occurrence of Actinobacillus actinomycetemcomitans (A.a.) in 19 Finnish patients with localized juvenile periodontitis (LJP) was studied. Clinical examination included the Plaque Index, Gingival Index, suppuration, probing depth and bleeding on probing. The subgingival bacterial samples were taken from two diseases periodontal pockets with radiographic bone loss and two periodontal pockets exhibiting no radiographic alveolar bone loss. The results indicate that A.a. was isolated in 17 (89%) patients, in 68% of the diseased and in 32% of the control periodontal sites. Supragingival plaque, marginal gingival inflammation, gingival bleeding on probing, and suppuration were found as frequently in A.a.-positive as in A.a.-negative diseased LJP pockets. It was concluded that A.a. was frequently, but not always, detected in diseased LJP lesions. No association was found between the clinical status and the occurrence of A.a.     

Periodontopathic bacteria in children with Down syndrome

BACKGROUND: It is widely known that individuals with Down syndrome (DS) often develop severe early-onset periodontal diseases. In this study, we examined the prevalence of periodontopathic bacteria in DS children to determine if specific pathogens are acquired in their childhood. METHODS: The subjects were 60 DS children (2 to 13 years old, 5 in each age bracket) and 60 age-matched controls. Ten pathogens, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides forsythus, Treponema denticola, Prevotella intermedia, P nigrescens, Capnocytophaga ochracea, C. sputigena, Campyrobacter rectus, and Eikenella corrodens were surveyed in subgingival plaque samples using a polymerase chain reaction. Periodontal status was evaluated by probing depth, bleeding on probing, and gingival index. RESULTS: No significant difference in periodontal status was observed between the DS and control groups, however, all of the pathogens were detected with greater frequency in the DS children. B. forsythus, T. denticola, P. nigrescens, and C. rectus were significantly prevalent throughout all age brackets of the DS children (P <0.01 or 0.05). The occurrence of P. gingivalis was also significant in the DS subjects over 5 years old. A cluster analysis of the microbial profiles of the DS subjects showed that gingivitis severity was associated with increased varieties of the harboring pathogens and the distribution of P. gingivalis. CONCLUSIONS: These results suggest that various periodontopathogens can colonize in the very early childhood of DS patients and maturation of subgingival components, including P. gingivalis, plays an important role in the initiation of gingival inflammation.     

Microbial associations in periodontitis sites before and after treatment

Duplicate samples from 110 periodontal sites of 6 mm or more pocket depth in 16 patients were analyzed for the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Capnocytophaga spp., Campylobacter rectus, Eikenella corrodens and Fusobacterium nucleatum. The sites were sampled before and after nonsurgical periodontal treatment. No statistically significant associations were found before treatment between any of the analyzed species. After treatment, statistically significant associations were found between E. corrodens and all the other species, F. nucleatum and P. intermedia; Capnocytophaga spp. and C. rectus; P. intermedia vs Capnocytophaga spp. and P. gingivalis ; and C. rectus vs Capnocytophaga spp. and A. actinomycetemcomitans. Some of these associations could be explained either by patient-related factors or site-related characteristics such as the pocket depth. The proportion of P. gingivalis seemed to be unrelated to the proportion of P. intermedia in the samples. If one of the analyzed microbes was found in one of the sampled pockets in a patient, the probability of finding that microbe in all the sampled sites in the same patient before treatment was more than 50%. This probability was reduced after treatment for many species, especially P. gingivalis , which showed a probability of zero. The probability of detecting a bacterial species on at least one additional site if it was present on one in the same individual was nearly 100%, both before and after treatment, for all species studied. This study has shown several potential microbial associations in the subgingival plaque flora of deep periodontal pockets. Local factors of the periodontal pocket and factors related to the individual may mask the biological significance of these microbial interactions.     

Persistent bacterial colonization of Porphyromonas gingivalis, Prevotella intermedia, and Actinobacillus actinomycetemcomitans in periodontitis and its association with alveolar bone loss after 6 months of therapy

BACKGROUND, AIMS: The purpose of this study was to determine whether the presence of bacterial antigens for Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), and Actinobacillus actinomycetemcomitans (Aa) in subgingival plaque of periodontitis patients after periodontal treatment was associated with progressive alveolar bone loss. METHOD: 39 (39) subjects in good general health previously diagnosed with adult periodontitis within the last 2 years, and still presenting with probing depth >5 mm in 2 to 6 teeth, were studied. All subjects were treated with scaling and root planing. Half of the subjects were randomly assigned to receive adjunctive systemic doxycycline (200 mg the 1st day, then 100 mg per day for 21 days). Subgingival plaque samples were taken at baseline, 1, 3 and 6 months after therapy. A modified ELISA test (Evalusite, Periodontal Test Kit, Eastman Kodak Co., Rochester, NY) was used to test for plaque antigens associated with P. gingivalis, P. intermedia and A. actinomycetemcomitans. Progressive alveolar bone loss was determined using digital subtraction radiography with standardized radiographs taken at baseline and 6 months after treatment. RESULTS: The presence of P. gingivalis in plaque after treatment was significantly associated with progressive bone loss (positive predictive value 84%, negative predictive value 85%, odds ratio 31.9, p<0.0001). In contrast, the presence of P. intermedia in plaque after treatment was not indicative of progressive loss (positive predictive value 39%, negative predictive value 82%). Too few sites had evidence of A. actinomycetemcomitans to be amenable to statistical analysis. No significant difference in bone loss was attributable to the systemic antibiotic therapy. CONCLUSION: These data indicated that, in this population, the presence of P. gingivalis in plaque after treatment might be indicative of progressive alveolar bone loss.     

Distribution of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia in an Australian population

BACKGROUND, AIM: The present study describes (i) the natural distribution of the three putative periodontopathogens Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans in an Australian population and (ii) the relationship between these organisms, pocket depths and supragingival plaque scores. METHODS: Subgingival plaque was collected from the shallowest and deepest probing site in each sextant of the dentition. In total, 6030 subgingival plaque samples were collected from 504 subjects. An ELISA utilising pathogen-specific monoclonal antibodies was used to quantitate bacterial numbers. RESULTS:: A. actinomycetemcomitans was the most frequently detected organism (22.8% of subjects) followed by P. gingivalis and P. intermedia (14.7% and 9.5% of subjects respectively). The majority of infected subjects (83%) were colonised by a single species of organism. A. actinomycetemcomitans presence was over-represented in the youngest age group but under-represented in the older age groups. Conversely, P. gingivalis and P. intermedia presence was under-represented in the youngest age group but over-represented in the older age groups. Differing trends in the distribution of these bacteria were observed between subjects depending upon the site of the infection or whether a single or mixed infection was present; however, these differences did not reach significance. Bacterial presence was strongly associated with pocket depth for both A. actinomycetemcomitans and P. gingivalis. For A. actinomycetemcomitans, the odds of a site containing this bacterium decrease with deeper pockets. In contrast, for P. gingivalis the odds of a site being positive are almost six times greater for pockets >3 mm than for pockets < or =3 mm. These odds increase further to 15.3 for pockets deeper than 5 mm. The odds of a site being P. intermedia positive were marginally greater (1.16) for pockets deeper than 3 mm. CONCLUSIONS: This cross-sectional study in a volunteer Australian population, demonstrated recognised periodontal pathogens occur as part of the flora of the subgingival plaque. Prospective longitudinal studies are needed to examine the positive relationship between pocket depth and pathogen presence with periodontal disease initiation and/or progression.     

Rate of cultivable subgingival periodontopathogenic bacteria in chronic periodontitis

Although microbiological studies have identified more than 400 bacterial species in periodontal pockets, only a limited number have been implicated as periodontal pathogens. The purpose of this study was to investigate the incidence of cultivable subgingival periodontopathogenic bacteria in chronic periodontitis. Bacterial samples were collected with sterile paper points from the deepest periodontal pockets ((5 mm) of 203 patients: 92 males and 111 females, aged 35-55 years. The samples were cultured under anaerobic and capnophilic conditions using selective and non-selective media. Isolates were characterized to species level by conventional biochemical tests and a commercial rapid test system. The isolates were Actinobacillus actinomycetemcomitans (26.8%), Porphyromonas gingivalis (21.9%), Capnocytophaga sputigena (16.7%), Eikenella corrodens (13.2%), Prevotella intermedia (10.5 %), Prevotella disiens (3.1%), Peptostreptococcus micros (2.9%), Capnocytophaga gingivalis (2.2%), Prevotella corporis (1.8%), Peptostreptococcus magnus (1.3%) and Fusobacterium nucleatum (0.4%). No periodontopathogenic bacterial growth was observed in 14 of the samples (6.2%). The number of samples associated with monobacterial growth and polybacterial growth were 74.9% and 18.2% respectively. It is concluded that the bacterial composition associated with a number of patients' samples is quite complex, and that some of cultivable anaerobic and capnophilic bacteria act as periodontal pathogens in chronic periodontitis.     

Periodontal findings in spouses

Abstract Clinical, radiographic and microbiological examination of periodontal conditions was carried out in 2 groups of married couples to assess similarities between husband and wife. The diseased probands (n=10) exhibited advanced periodontitis and the healthy ones (n=10) were periodontally normal. The clinical examination comprised the assessment of plaque, probing pocket depths, gingival bleeding on probing, suppuration, supragingival and subgingival calculus. The extent and type of alveolar bone loss was determined from panoramic radiographs. Bacterial samples were taken from the 6 deepest and most inflamed periodontal pockets and from stimulated saliva. The samples were cultured for Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Campylobacter rectus and Peptostreptococcus micros. The mean detection frequency of moderately deep pockets (4–5 mm) and deep pockets (6 mm) was significantly higher in the diseased probands than in their spouses. The mean detection frequency of moderately deep pockets was significantly higher in the spouses of the diseased probands than in the spouses of the healthy ones. Deep pockets were found in 6 spouses of the diseased probands, whereas only in 2 spouses of the healthy ones. Both diseased proband and his/her spouse harbored A. actinomycetemcomitans, P. gingivalis, P. intermedia, C. rectus and P. micros in 4, 6, 9, 9 and 4 couples, respectively. Both healthy proband and his/her spouse harbored the pathogens in 0, 1, 9. 5 and 3 couples, respectively. P. gingivalis was found in 7 spouses of the diseased probands, but only in 2 spouses of the healthy ones. The results indicate that spouses of patients with advanced periodontitis may also exhibit frequent recovery of suspected periodontal pathogens and have a worse periodontal status than spouses of periodontally healthy subjects.     

Actinobacillus actinomycetemcomitans,Capnocytophaga and Porphyromonas gingivalis in subgingival plaque of adolescents with Down's syndrome

Levels of Actinobacillus actinomycetemcomitans, Capnocytophaga and Porphyromonas gingivalis were determined in subgingival plaque samples from 37 adolescents with Down's syndrome and 37 healthy controls matched with respect to age and sex. Gingival inflammation, supra- and subgingival calculus, periodontal pockets (>4 mm) and alveolar bone loss were registered. Alveolar bone loss was more frequent in Down's syndrome subjects (32%) than in the controls (3%). A. actinomycetemcomitans was detected in the subgingival plaque in 35% of the Down's syndrome adolescents and in 5% of the controls. On site level, A. actinomycetemcomitans and Capnocytophaga were more frequent in the subgingival plaque samples of Down's syndrome children than in those of controls. Comparing Down's syndrome subjects positive or negative for A. actinomycetemcomitans and Capnocytophaga, no significant differences were found in terms of gingival inflammation, periodontal pockets (>4 mm) or number of sites with alveolar bone loss. The results indicate an altered microbial composition of the subgingival plaque of Down's syndrome subjects compared with healthy controls, with higher frequency of A. actinomycetemcomitans.     

Sulfate-reducing bacteria in relation with other potential periodontal pathogens

BACKGROUND, AIMS: Oral sulfate-reducing bacteria are involved in several clinical categories of periodontitis. The aim of this cross-sectional study was to compare the presence of sulfate-reducing bacteria (SRB) with other putative pathogens including spirochetes, Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Porphyromonas gingivalis, and Treponema denticola in periodontal lesions. METHOD: Periodontal SRB were detected by enrichment culture and compared with a microscopic spirochete count (n=168). Species-specific oligonucleotide probes directed against the 16S rRNA were employed to determine the presence of A. actinomycetemcomitans, P. gingivalis, B. forsythus, and T. denticola (n=55). RESULTS: A significant positive correlation was observed between the presence of SRB and the proportions of spirochetes in subgingival plaque, although the 2 bacterial groups also occurred separately. SRB tended to be negatively correlated with the presence of A. actinomycetemcomitans. In contrast, all pockets with SRB harbored either T. denticola, or both T. denticola and B. forsythus (12/14) before therapy. Interestingly, the combination of SRB with P. gingivalis occurred in 32% of the periodontal pockets before treatment. After initial periodontal therapy, the prevalence of this combination was reduced to 2% of the sites, and to 25% of the sites in recall patients. CONCLUSION: The presence of SRB was positively correlated with T. denticola, B. forsythus, and P. gingivalis in periodontal lesions. These suspected pathogens form a complex strongly associated with destructive periodontitis.     

Early colonization of dental implants by putative periodontal pathogens in partially edentulous patients

There is limited scientific information available on the early colonization of the peri-implant pockets in partially edentulous individuals. Knowledge about this process is one step in better understanding the etiology and pathogenesis of peri-implantitis. In this study, the early colonization of the peri-implant pockets by putative periodontal pathogens was studied in 20 partially edentulous individuals using anaerobic culture techniques. At baseline, the presence and levels of putative periodontal pathogens in the microflora of periodontal pockets and saliva were established. Immediately after loading of the titanium implants and after 6 and 12 months the presence and levels of selected putative periodontal pathogens were determined in periodontal and peri-implant pockets. A second aim was to detect bacterial contamination of the implant site and the inside of the implant. At baseline, the most frequently isolated species from the periodontal pockets were Fusobacterium nucleatum, Prevotella intermedia and Peptostreptococcus micros. Bacteroides forsythus, Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were isolated from 9, 2 and 3 patients respectively. Six months after placing of the bridges, the majority of the implant sites had detectable levels of most periodontal bacterial species with the exception of A. actinomycetemcomitans which could not be isolated from any of the peri-implant samples during the experimental period, although 2 patients had this organism at baseline. In 2 patients with detectable subgingival P. gingivalis at baseline this species was found after 12 months in the peri-implant sites. One of these patients lost 2 implants which was associated with a high proportion of P. gingivalis in the peri-implant pockets. A second patient developed 2 fistulas around 2 implants at 8 months and this event was also associated with the presence of P. gingivalis. It is concluded that proper periodontal infection control before installment of dental implants in partially edentulous patients may prevent early bacterial complications.     

Prevalence and microbiology of localized prepubertal periodontitis

Loss of crestal alveolar bone at primary teeth was ascertained radiographically in a dental school clinical population of 2264 children. 19 patients (0.84%) demonstrated distinct periodontal bone destruction around one or more primary teeth; in only 2 of these patients had periodontal disease been identified in previous clinical examinations. A microbiological study of 35 subgingival samples from 9 available patients revealed a high prevalence of black-pigmented Bacteroides spp., mainly Bacteroides intermedius. Actinobacillus actinomycetemcomitans and Capnocytophaga spp. were predominant organisms in some samples. The present data indicate that localized prepubertal periodontitis is more common than previously realized and is associated with bacteria generally regarded as major periodontal pathogens.     

Association between bacteriophage-infected Actinobacillus action-mycetemcomitans and rapid periodontal destruction

Actinobacillus actinomycetemcomitans was isolated from periodontal pockets in a patient suffering from prepubertal periodontitis. Electron microscopy revealed 3 different groups of bacteriophages in filtrates of subgingival plaque from all the active periodontal lesions. Phage infected A. actinomycetemcomitans in this patient was restricted to periodontal pockets which, according to standardized roentgenograms, had shown bone destruction during the past 12 months. A follow-up study of 7 months revealed that a "burned out" site which harbored noninfected A. actinomycetemcomitans, turned into an active site at the same time as the A. actinomycetemcomitans of that site became infected with the phages. These findings indicate a relationship between rapid prepubertal periodontal destruction and phage-infected A. actinomycetemcomitans.     

Prevalence of periodontopathic bacteria in aggressive periodontitis patients in a Chilean population

BACKGROUND: Actinobacillus actinomycetemcomitans is considered a major etiologic agent of aggressive periodontitis (AgP). Other periodontopathic bacteria such as Porphyromonas gingivalis are also suspected of participating in aggressive periodontitis although the evidence to support this is controversial. The aim of the present study was to determine the prevalence of eight periodontopathic bacteria in Chilean patients with AgP. METHODS: Subgingival plaque samples were collected from 36 aggressive, 30 localized, and six generalized periodontitis patients. Samples from 17 advanced chronic periodontitis (CP) patients were taken as controls. Samples collected from the four deepest periodontal pockets in each patient were pooled in prereduced transport fluid (RTF) and cultured. Periodontal bacteria were primarily identified by colony morphology under stereoscopic microscope and rapid biochemical tests. The identity of some bacterial isolates was confirmed by colony polymerase chain reaction (PCR). RESULTS: AgP showed a significatively higher prevalence of C. rectus than CP (P = 0.036). The only statistical difference found was for C. rectus. Patients with AgP showed a higher, but not statistically significant, prevalence of P. gingivalis, E. corrodens, P. micros, and Capnocytophaga sp. A similar prevalence in both groups of patients was observed for F. nucleatum and P. intermedia/nigrescens, and A. actinomycetemcomitans was less prevalent in AgP than CP patients. In localized AgP, P. intermedia/nigrescens, E. corrodens, F. nucleatum, and P. micros were the more prevalent pathogens in contrast to generalized AgP patients who harbored A. actinomycetemcomitans, P. gingivalis, and Capnocytophaga sp. as the most prevalent bacteria. CONCLUSIONS: C. rectus, P. gingivalis, E. corrodens, P. micros, and Capnocytophaga sp. were the most predominant periodontopathic bacteria of AgP in this Chilean population, but the only statistical difference found here between AgP and CP was for C. rectus, suggesting that the differences in clinical appearance may be caused by factors other than the microbiological composition of the subgingival plaque of these patients. In this study, the prevalence of A. actinomycetemcomitans was much lower than that of P. gingivalis.