Selective medium for isolation of Actinobacillus actinomycetemcomitans

CARD15 gene mutations in periodontitis

OBJECTIVES

The CARD15 gene encodes the Nod2 protein, which is involved in intracellular recognition of bacterial products like peptidoglycan, activates inflammation and regulates apoptosis through nuclear factor-kappa B, a transcription factor that plays a central role in the innate immunity. Two functional mutations, an insertion mutation at nucleotide 3020 (3020insC) and a missense mutation C2104T in the CARD15 gene (originally NOD2 gene) have been reported to be associated with Crohn's disease. Our aim was to investigate the occurrence of CARD15 gene polymorphisms in adult patients with periodontitis taking into account smoking and presence of putative periodontal pathogens as additional variables.

MATERIAL AND METHODS

A case-control study was performed in 104 Dutch Caucasian patients with severe adult periodontitis (54 non-smokers and 50 smokers, mean age 46 years) and in 97 ethnically matched, periodontal healthy controls (73 non-smokers and 24 smokers, mean age 40 years). DNA isolated from a mouthwash was typed with PCR technology. Presence of putative periodontal pathogens was established by culture technique.

RESULTS

Frequencies of the CARD15 3020insC and 2104T mutations were similar in the periodontitis group and in the control group (5.1% and 13.3%; 5.2% and 10.3%, respectively). The highest carrier frequency of CARD15 mutations was found in non-smoking patients without Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans (29.4% versus 17.4% in controls); however it did not reach statistical significance.

CONCLUSION

Our results suggest no role for CARD15 3020insC and C2104T mutations in adult periodontitis.

Clonal diversity and stability of subgingival Eikenella corrodens

Eikenella corrodens is a commensal subgingival bacterium commonly found in both periodontally nondiseased and diseased subjects. The present study examined the clonal diversity and stability of subgingival E. corrodens over time. Ninety-five subjects were enrolled at the baseline examination, including 44 periodontally nondiseased subjects and 51 subjects with aggressive periodontitis. Twenty-two nondiseased subjects and 11 subjects with aggressive periodontitis were subsequently reexamined after an average interval of 14 months. Two subgingival plaque samples were obtained from each subject to determine the total cultivable bacteria. In addition, multiple E. corrodens isolates from each sample were recovered for clonal analysis by arbitrarily primed PCR. The mean numbers of distinct E. corrodens clones harbored by nondiseased subjects and subjects with aggressive periodontitis were 1.3 and 3.0, respectively. Thirty-nine percent of the nondiseased subjects and 63% of the subjects with aggressive periodontitis harbored multiple clones of E. corrodens. The numbers of distinct E. corrodens clones increased significantly (Mann-Whitney ranking test, P < 0.05) in sites from patients with aggressive periodontitis, in sites with pocket depths of 4 mm or greater, in sites with a clinical attachment loss of 2 mm or greater, and in sites coinfected with Porphyromonas gingivalis. Comparison of E. corrodens clones recovered at the baseline and those recovered at the follow-up examination showed that E. corrodens colonization was not stable. Thirty-eight of the 66 follow-up samples (58%) showed a complete change (including de novo colonization of the sites or complete elimination of the organism from the sites) of the subgingival E. corrodens clonal types between the baseline and the follow-up examinations. Our results suggest a complexity of subgingival microbiota not seen previously.

Bacteremia following surgical dental extraction with an emphasis on anaerobic strains

Our aim was to investigate bacteremia caused by surgical extraction of partly erupted mandibular third molars. From 16 young adults, bacterial samples were taken from the third-molar pericoronal pocket and post-operatively from the extraction socket, and blood samples were drawn from the ante-cubital vein up to 30 min after surgery. Of the subjects, 88% had detectable bacteremia-50% 1 min after the incision, 44% immediately after extraction. The respective percentages at 10, 15, and 30 min were 44%, 25%, and 13%. Blood cultures contained 31 species (74% anaerobes), with 3.9 +/- 2.6 species isolated per subject. Most prevalent were the anaerobes Prevotella, Eubacterium, and Peptostreptococcus sp. and the aerobes viridans-group streptococci and Streptococcus milleri group. Any species found in the blood was also isolated from the mouth, from 93% of the pericoronal pockets and from 43% of the extraction sockets. Surgical dental extraction clearly causes bacteremia of a high frequency and lasting longer than thus far assumed.

Identification of an extracellular matrix protein adhesin, EmaA, which mediates the adhesion of Actinobacillus actinomycetemcomitans to collagen

Actinobacillus actinomycetemcomitansis an aetiologic agent in the development of periodontal and some systemic diseases in humans. This pathogen localizes to the underlying connective tissue of the oral cavity in individuals with periodontal disease. The adhesion ofA. actinomycetemcomitansto extracellular matrix components of the connective tissue prompted this study to identify gene products mediating the interaction ofA. actinomycetemcomitansto these molecules. A transposon mutagenesis system was optimized for use inA. actinomycetemcomitansand used to generate an insertional mutant library. A total of 2300 individual insertion transposon mutants were screened for changes in the adhesion to collagen and fibronectin. Mutants were identified which exhibited the following phenotypes: a decrease in collagen binding; a decrease in fibronectin binding; a decrease in binding to both proteins; and an increase in binding to both collagen and fibronectin. The identification of mutants defective in adhesion to the individual proteins indicates that distinct adhesins are expressed by this organism. Molecular analysis of these mutants implicated 11 independent loci in protein adhesion. One gene,emaA, is likely to encode a direct mediator of collagen adhesion, based on predicted protein features homologous to the collagen-binding protein YadA ofYersinia enterocolitica. EmaA was localized to the outer membrane, as expected for an adhesin. Reduction in fibronectin adhesion appeared to be influenced by abrogation of proteins involved in molybdenum-cofactor biosynthesis. Several other loci identified as reducing or increasing adhesion to both collagen and fibronectin are suggested to be involved in regulatory cascades that promote or repress expression of collagen and fibronectin adhesins. Collectively, the results support the hypothesis thatA. actinomycetemcomitanshost colonization involves afimbrial adhesins for extracellular matrix proteins, and that the expression of adhesion is modulated by global regulatory mechanisms.

Relationship of Subgingival and Salivary Microbiota to Gingival Overgrowth in Heart Transplant Patients Following Cyclosporin A Therapy

BACKGROUND

Severe gingival overgrowth (GO) is induced in patients taking cyclosporin A (CsA) following organ transplantation. Determining which patient will develop GO is still not possible. The purpose of this study was to establish an association between CsA and gingival overgrowth in heart transplant patients taking into account periodontal and microbiological conditions.

METHODS

Thirty patients (10 female, 20 male; range: 13 to 67 years; mean age: 44.89) undergoing CsA treatment were evaluated using the gingival index (GI), plaque index (PI), probing depth (PD), and clinical attachment level (CAL). Subgingival samples collected from the deepest site of each quadrant and saliva samples were submitted to microbial analysis. All patients had at least 12 teeth. Exclusion criteria were the use of antibiotics and/or having undergone periodontal treatment 6 months prior to the study. Patients were divided in two groups: with gingival (GO+) and without gingival overgrowth (GO-).

RESULTS

There were no statistically significant differences between the GO+ and GO- groups when CsA dosage, time since transplant, GI, PI, PD, and CAL were compared. Microbiological examination of the subgingival samples detected the following microorganisms: Actinobacillus actinomycetemcomitans (23%), Porphyromonas gingivalis (36%), Prevotella intermedia (93%), Fusobacterium sp. (66%), Campylobacter rectus (30%), Micromonas micros (66%), enteric rods (0%), and yeasts (30%). A positive association between M. micros and the GO+ group was found (P < 0.001). Yeasts were detected in 30% of the subgingival and saliva samples.

CONCLUSIONS

Clinical parameters were not sufficient to determine which patients would develop GO. However, colonization by M. micros might play a role in the etiology of GO.

Bacteremia after plate removal and tooth extraction

Our aim was to investigate the occurrence of bacteremia associated with removal of a semirigid osteosynthesis plate and an adjacent third molar. Ten patients with fixed mandibular angle fracture were bacteriologically sampled from the second molar's distal gingival pocket, from the third molar's extraction socket and from the osteosynthesis plate. Blood samples from the ante-cubital vein were taken 10 times until 30 min postoperatively. Established culture, isolation and identification methods for the bacterial species were used. Bacteremia was detected in 60% of the subjects, most frequently 1.5 min after removal of the plate (20%) and 1.5 and 5 min after extraction of the tooth (20%), but also 10 min (10%) and 30 min (10%) postoperatively. 13 different bacterial species or groups were isolated, mean 2.5 +/- 1.9 per bacteremia-positive subject. The majority (85%) were anaerobes with Actinomyces, Campylobacter and Lactobacillus species predominating. In all the blood culture-positive cases the corresponding species was also recovered from one or more of the oral samples. These results show that oral surgical procedures are associated with a high frequency of longstanding anaerobic bacteremia, which could be harmful in patients at risk.

Clinical and microbiological effects of subgingival administration of two active gels on persistent pockets of chronic periodontitis patients

OBJECTIVES

The present controlled, single-blind study was performed to assess and compare the clinical healing and the microbiological findings following repeated intrasulcular applications of 1% metronidazole or 1% chlorhexidine gels in persistent periodontal pockets previously treated by scaling and root planing (SRP).

MATERIAL AND METHODS

Sixty-three systemically healthy subjects, 25 males and 38 females (mean age 48.4+/-7.2 years), diagnosed for chronic periodontitis were enrolled in this study. They underwent SRP and received oral hygiene instructions (OHI). Three months later, at baseline, a single persistent pocket with a probing depth (PD) of 5-9 mm was chosen as the experimental site in each patient; the subjects were stratified into three matched experimental groups on the basis of the treatment to be performed, which consisted of the subgingival administration of 1% metronidazole gel (MG, n=19), 1% chlorhexidine gel (CG, n=20) or placebo gel (PG, n=24). The treatments consisted of four repeated administrations of subgingival gels, each separated by 7 days, starting at the baseline. Clinical assessment was performed at the baseline and at the 180-day follow-up, after the end of treatment. For microbiological evaluations, subgingival plaque was sampled from the experimental sites at baseline, prior to the first subgingival gel administration, and at 7, 15, 30 and 90 days after the end of the treatment (days 28, 36, 51 and 111 from baseline).

RESULTS

Plaque accumulation did not change significantly in all three groups. Bleeding on probing and clinical attachment levels reduced in the MGs and CGs only. PD was significantly reduced by the same amount in all experimental groups. In the MGs and CGs a remarkable reduction in the frequencies of detection of several periodontopathic micoorganisms was recorded after the treatment. The same was not seen for the PGs.

CONCLUSIONS

Subgingival administration of MG or CG, both at 1%, may have a role in the management of persistent pockets during chronic periodontitis.

Longitudinal monitoring of subgingival colonization by Actinobacillus actinomycetemcomitans, and crevicular alkaline phosphatase and aspartate aminotransferase activities around orthodontically treated teeth

OBJECTIVES

During orthodontic treatment, changes in subgingival plaque colonization and tissue inflammation and remodelling have been described. This study uses a longitudinal design to examine subgingival colonization of Actinobacillus actinomycetemcomitans (Aa) and alkaline phosphatase (ALP) and aspartate aminotransferase (AST) activities in gingival crevicular fluid (GCF) in order to assess whether these parameters have potential as biomarkers of tissue responses to orthodontic tooth movement in humans.

MATERIALS & METHODS

Twenty-one patients (ages: 11.2-22.5; mean 17.1 +/- 3.3 years) participated in the study. An upper canine from each patient undergoing treatment for distal movement served as the test tooth (DC), and its contralateral (CC) and antagonist (AC) canines were used as controls. The CC was included in the orthodontic appliance, but was not subjected to the orthodontic force; the AC was free from any orthodontic appliance. The subgingival plaque and GCF around the experimental teeth was harvested from both mesial and distal tooth sites immediately before appliance activation and on day 28. Clinical gingival condition was evaluated at the baseline and at the end of the experimental period. Aa colonization was determined by culture methods, while ALP and AST activities were evaluated spectrophotometrically.

RESULTS

Throughout the study, the clinical conditions worsened in both the DCs and the CCs as compared with the baseline, whereas no significant differences were found between the DCs and the CCs, or between mesial and distal sites of each of these teeth on day 28. In the ACs, clinical parameters remained at baseline levels throughout the study. Similar results were found for Aa colonization, which increased significantly on day 28 in the DC and CC groups. On day 28, ALP and AST activities were significantly elevated in all sites from the DC and CC groups as compared with the ACs, where, conversely, enzymatic activities remained at the baseline levels. However, ALP activity in the DC group was significantly greater than in the CCs at mesial (tension) sites on day 28, while AST activity in the DCs was significantly elevated as compared with the CC group at the distal (compression) sites. Greater ALP activity in the DC group was observed at the tension sites compared with the compression sites on day 28.

CONCLUSIONS

Our results suggest that Aa subgingival colonization, and ALP and AST activities in GCF reflect the tissue responses that occur in the periodontium during orthodontic treatment.

Relationship ofActinobacillus actinomycetemcomitansSerotype b to Aggressive Periodontitis: Frequency in Pure Cultured Isolates

BACKGROUND

To our knowledge, the association of the five serotypes of Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) to the new diagnostic classification scheme defined by the American Academy of Periodontology in 1999 has not yet been described. The goal of this study was to characterize the frequencies of the five serotypes of A. actinomycetemcomitans in A. actinomycetemcomitans isolates from various forms of periodontitis using both old and new diagnostic classifications and to determine the relationships between serotype and age and clinical diagnosis.

METHODS

A total of 345 A. actinomycetemcomitans isolates from 115 A. actinomycetemcomitans culture-positive subjects (mean age 38.0 +/- 18.3 years, 59% female) were collected. Based on the new classifications, 33 subjects had aggressive periodontitis and 82 chronic periodontitis. According to old classifications, there were six prepubertal periodontitis (PPP), 12 localized juvenile periodontitis (LJP), 15 post-localized juvenile periodontitis (PLJP), 28 refractory periodontitis (Ref-P), and 54 adult periodontitis (AP) cases. Serotypes of A. actinomycetemcomitans were determined by an indirect immunofluorescence assay using serotype-specific polyclonal antisera to A. actinomycetemcomitans strains ATCC 29523, ATCC 43728, ATCC 33384, IDH 781 and IDH 1705 (serotype a, b, c, d, and e, respectively). Proportions of serotype b were examined between different diagnostic and age groups with a Z-test for proportions.

RESULTS

Most subjects (n = 100, 86.96%) were infected with a single serotype (22 serotype a, 44 serotype b, 30 serotype c, 1 serotype d, and 3 serotype e). There were 11 subjects (9.57%) with two serotypes and two subjects (1.74%) with 3 serotypes. Two individuals had isolates lacking any detectable serotype antigen. Serotype b was the predominant serotype in children under 18 years of age and young adults between 19 to 35 years, although serotype b status was not significantly associated with age. Serotypes d and e were not found in patients under 35 years old. In 62 adult patients, one subject had serotype d and three had serotype e. Serotype b was the most common serotype in aggressive periodontitis (60.61%). The proportion of cases with serotype b was significantly higher in aggressive periodontitis compared to chronic periodontitis (P = 0.031). Other serotypes were not significantly associated with new diagnostic categories. Serotypes d and e were not detected in aggressive periodontitis.

CONCLUSION

The results of this study show that proportions of serotype b of A. actinomycetemcomitans are significantly greater in culture-positive patients with aggressive periodontitis than those with chronic periodontitis.

Clinical effects of scaling and root planing in adults infected with Actinobacillus actinomycetemcomitans

The periodontal pathogen Actinobacillus actinomycetemcomitans can frequently be isolated from subgingival plaque of adults with chronic inflammatory periodontal disease and individuals with plaque-induced gingivitis. Problems with the persistence of the organism after thorough debridement of root surfaces have been reported. In the present study clinical effects of the hygienic phase of periodontal therapy in ten adult patients with moderate or advanced periodontitis harbouring A. actinomycetemcomitans were analysed. Since proper analysis of highly correlated data within a given patient is crucial for appropriate interpretation, a major objective of this study was to compare the results of different models derived from logistic regression of clinical and microbiological factors on gain or loss of clinical attachment under different assumptions. Subgingival samples from every tooth present were obtained before and 6 weeks after thorough subgingival scaling, and selectively cultivated for the organism. A relevant gain of clinical attachment of 2 mm or more was observed at a total of 36% of periodontitis sites after scaling. Overall, loss of attachment of 2 mm or more was observed at 8% sites. Most loss occurred at sites with gingival enlargement (15%), whereas 3% periodontitis sites lost 2 mm or more. In multivariate analyses erroneously assuming either independence of data or correctly considering the correlated structure of observations attachment gain was mainly associated with deep probing depths at the outset. Presence or absence of A. actinomycetemcomitans before or after therapy was not included into the periodontitis models. Also, loss of attachment of 2 mm or more after subgingival scaling was not influenced by the organism. A direct comparison of the results obtained with both approaches of logistic regression may be helpful in the assessment of the influence of the magnitude of correlation of the data on the regression coefficients.

Herpesviral-bacterial Coinfection in Periapical Pathosis

Two members of the herpesvirus family, human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV), seem to be important putative pathogens of human periodontitis and symptomatic periapical lesions, causing pathosis either by inducing immunosuppression with a subsequent risk of aggressive bacterial infections or by infecting of periodontal cells directly. This study aimed to relate periapical occurrence of HCMV, EBV, and herpes simplex virus active infections to clinical characteristics of periapical lesions and periapical bacterial flora. Microbial samples were collected from 34 periapical lesions in conjunction with periapical surgery. Part of the periapical specimen was frozen for virologic examination, and another part was transferred to anaerobic transport medium for bacteriologic examination. RNA was isolated by means of a guanidinium isothiocyanate-acid phenol procedure, and cDNA was produced using herpesvirus-specific primers and reverse-transcription polymerase chain reaction amplification. Bacteriologic examination was performed according to established anaerobic culture methods. Of the 34 periapical lesions studied, 20 showed both HCMV and EBV, seven showed only HCMV, one showed only EBV, and six showed neither HCMV nor EBV. Herpes simplex virus was detected in two lesions. Higher occurrence of herpesvirus was detected in large versus small periapical lesions (p < 0.001) and in symptomatic versus asymptomatic periapical lesions (p < 0.001). A total of 18 microbial groups and an average of 2.1 to 3.0 bacterial groups were isolated from various categories of periapical lesions. The important finding of this study was that most teeth with necrotic pulp and periapical lesions harbored herpesviruses in periapical granulomatous tissue. Herpesvirus species in cooperation with endodontopathic bacteria may play major roles in the etiopathogenesis of aggressive types of periapical pathosis in humans.

Induction of T-cell apoptosis by Actinobacillus actinomycetemcomitans mutants with deletion of ltxA and cdtABC genes: possible activity of GroEL-like molecule

The pathogenic bacterium Actinobacillus actinomycetemcomitans expresses a leukotoxin (Ltx) and cytolethal distending toxin (CDT) with cytolytic properties. CDT also has cytostatic properties, inducing a G2 cell cycle block. The extent of the contribution of these, as well as other toxins, to the cytolytic and cytostatic activities of this microorganism have not been defined and the aim of this study was to determine their contribution. To that end, a naturally transformable A. actinomycetemcomitans clinical strain (D7S-smooth) was used to construct a series of deletion mutants (DeltacdtA, DeltacdtB, DeltacdtC, DeltacdtABC, DeltaltxA, DeltaltxA/DeltacdtABC). Human peripheral blood mononuclear cells were incubated with cell-associated and extracellular bacterial preparations. The ability of wild type and isogenic mutants to induce T-cell apoptosis and cell cycle arrest was compared. The expression of ltxA and each of the cdt gene loci partially contributed to A. actinomycetemcomitans apoptosis, since each of the isogenic mutants exhibited reduced ability to induce T-cell apoptosis. Conversely, the ability to induce cell cycle block was abolished in each of the cdt isogenic mutants. A mutant with simultaneous deletion of ltxA and cdtABC genes retained potent ability to induce apoptosis in its cell-associated, but not extracellular, preparation. Neutralization with Escherichia coli anti-GroEL monoclonal antibody, lead to significant diminution of apoptosis-inducing activity of the DeltaltxA/DeltacdtABC cell-associated preparation. These data provide evidence for the expression of other A. actinomycetemcomitans cytolytic molecule(s) distinct from CDT and leukotoxin, with a possible role for GroEL-like molecule in T-cell apoptosis.

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

BACKGROUND

Actinobacillus actinomycetemcomitans is considered a major etiologic agent of aggressive periodontitis. Other periodontopathic bacteria such as Porphyromonas gingivalis are also suspected of participating in aggressive periodontitis, although the evidence is controversial. The aim of the present study was to investigate the prevalence of periodontopathic bacteria and to clarify the microbiological features of aggressive periodontitis in Japanese patients.

METHODS

Subgingival plaque was collected from 50 aggressive periodontitis (AgP) patients (localized 10, generalized 40). Samples from 35 generalized chronic periodontitis (CP) patients and 18 healthy subjects were examined as controls. Plaque samples were examined using culture and polymerase chain reaction (PCR) method.

RESULTS

The prevalence of A. actinomycetemcomitans was relatively low in the localized (20%) and generalized (17.5%) AgP patients, with no significant difference observed in detection frequencies between AgP and the control groups (CP 8.6%, healthy 0%). On the other hand, Tannerella forsythensis (formerly Bacteroides forsythus), Campylobacter rectus, P. gingivalis, and Treponema denticola were frequently detected in localized as well as generalized aggressive periodontitis patients. The prevalence and proportion of P. gingivalis correlated with severity of clinical attachment loss in both localized and generalized aggressive periodontitis.

CONCLUSIONS

T. forsythensis, C. rectus, P. gingivalis, and T. denticola were the predominant periodontopathic bacteria of aggressive periodontitis patients in Japan. Although A. actinomycetem- comitans was also detected in AgP patients, the prevalence of this bacterium was much lower than that of P. gingivalis.

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.

Effect of smoking and periodontal treatment on the subgingival microflora

BACKGROUND

The effect of smoking on the prevalence of periodontal pathogens after periodontal treatment is still not clear. Some studies found no effect of the smoking status on the prevalence of periodontal pathogens after therapy, whereas others did. The aim of this retrospective study was to investigate the influence of smoking on the treatment of periodontitis and the composition of the subgingival microflora.

METHOD

The study included 59 periodontitis patients (mean age 41.5 years): 30 smokers and 29 nonsmokers. The treatment consisted of initial periodontal therapy and, if necessary, surgery and/or antibiotics. Clinical and microbiological data were obtained before and after treatment at the deepest site in each quadrant. A pooled sample was analysed for the presence of Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotalla intermedia (Pi), Bacteroides forsythus (Bf), Fusobacterium nucleatum (Fn) and Peptostreptococcus micros (Pm).

RESULTS

For smokers and nonsmokers a significant improvement of the clinical condition was found after treatment. A decrease could be assessed for bleeding on probing (smokers: 0.46; nonsmokers: 0.52) and probing pocket depth (PPD) (smokers: 1.64 mm; nonsmokers: 2.09 mm). Furthermore, both groups showed gain of attachment (smokers: 0.68 mm; nonsmokers: 1.46 mm). No significant difference in bleeding on probing and PPD reduction was found between smokers and nonsmokers. In contrast, nonsmokers showed significantly more gain of attachment than smokers. The microbiological results revealed no differences in the prevalence of the various bacteria between smokers and nonsmokers before treatment. After treatment in nonsmokers, a significant decrease was found in the prevalence of Aa (11-3), Pg (17-7), Pi (27-11), Bf (27-11), Fn (28-20) and Pm (27-17). In smokers, a significant decrease could be shown only for the prevalence of Pg (15-5).

CONCLUSIONS

Nonsmokers showed more gain of attachment and a greater decrease in the prevalence of periodontal bacteria as compared to smokers. The phenomenon that among smokers, more patients remain culture positive for periodontal pathogens after therapy, may contribute to the often observed unfavourable treatment results in smoker periodontitis patients.

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.

Povidone-iodine as a periodontal pocket disinfectant

OBJECTIVES AND BACKGROUND

Povidone-iodine [polyvinylpyrrolidone-iodine complex (PVP-iodine)] might constitute a valuable adjunct to current periodontal therapy because of its broad-spectrum antimicrobial activity, low potential for developing resistance and adverse reactions, wide availability, ease of use, and low financial cost. This investigation employed a randomized, split-mouth study design to determine the microbiological and clinical effects of 10% PVP-iodine subgingival irrigation in periodontitis lesions showing radiographic evidence of subgingival calculus.

METHODS

Sixteen adults having at least one periodontal pocket of 6 mm or more in each quadrant of the dentition and harboring one or more periodontopathic bacteria participated in the study. In each subject, a study site in each quadrant was randomly chosen to receive either subgingival irrigation with 10% PVP-iodine together with scaling and root planing, scaling and root planing alone, subgingival irrigation with 10% PVP-iodine, or subgingival irrigation with sterile saline. Prior to therapy and at 5 weeks post-treatment, microbiological culture was carried out without knowledge of the clinical status or the type of treatment rendered. A blinded clinical examiner determined presence of dental plaque, probing pocket depth, and gingival bleeding on probing. Microbiological and clinical data were analyzed using a repeated measures analysis of variance and Kruskal-Wallis rank test with the Tukey and Mann-Whitney post hoc tests.

RESULTS

At 5 weeks post-treatment, subgingival irrigation with PVP-iodine together with scaling and root planing caused a 95% or greater reduction in total pathogen counts in 44% of pockets having >/= 6 mm depth whereas scaling and root planing alone, povidone-iodine irrigation alone and water irrigation alone caused 95% reduction of total pathogens only in 6-13% of similar study sites (P = 0.02). Reduction in mean pocket depth was 1.8 mm for the PVP-iodine/scaling and root planing group, 1.6 mm for the scaling and root planing group, and 0.9 mm for the PVP-iodine and the saline monotherapy groups, with statistical significance reached for the scaling and root planing group vs. the PVP-iodine group (P = 0.04) and for the scaling and root planing group vs. the saline group (P = 0.02). Reduction in visible dental plaque, which ranged from 38% to 62%, showed no significant differences among treatment groups.

CONCLUSIONS

The addition of subgingival PVP-iodine irrigation to conventional mechanical therapy may be a cost-effective means of reducing total counts of periodontal pathogens and helping control periodontal disease. However, subgingival irrigation with PVP-iodine without concomitant mechanical debridement might not improve microbiological and clinical variables in comparison with saline irrigation, at least not in sites with radiographic evidence of subgingival calculus.

Enzymatic degradation of collagen-guided tissue regeneration membranes by periodontal bacteria

Bacterial infection in the vicinity of guided tissue regeneration barrier membranes was shown to have a negative effect on the clinical outcomes of this increasingly used technique. Several oral and specifically periodontal bacteria were shown to adhere to such membranes in vivo and in vitro with a higher affinity to membranes constructed from collagen. The present study examined the role of periodontal bacteria and their enzymes in the degradation of commercially used collagen membranes. Degradation of two collagen membranes [Biomend (Calcitek, Colla-Tec Inc., Plainsboro, NJ) and Bio-Gide (Geistlich Biomaterials, Wolhousen, Switzerland)] labeled by fluorescein isothiocyanate was examined by measuring soluble fluorescence. Porphyromonas gingivalis, Treponema denticola and Actinobacillus actinomycetemcomitans and their enzymes were evaluated. Collagenase from Clostridium hystolyticum was used as a positive control. While whole cells of P. gingivalis were able to degrade both types of membranes, T. denticola could degrade Bio-Gide membranes only and A. actinomycetemcomitans whole cells could degrade none of the membranes. Fractionation of P. gingivalis cells revealed that cell membrane associated proteases were responsible for the degradation of the two collagen membranes. In T. denticola, the purified major phenylalanine protease was found to be responsible for the degradation of Bio-Gide membranes. These results suggest that proteolytic bacterial enzymes may take part in the degradation of collagen barrier membranes used for guided tissue regeneration.

Microbiology of mandibular third molar pericoronitis: incidence of beta-lactamase-producing bacteria

OBJECTIVES

The purpose of this study was to evaluate the predominant flora associated with pericoronitis in third molars and to investigate the presence of beta-lactamase-producing strains.

STUDY DESIGN

The third molars in 26 adults were evaluated by cultures with nonselective media and with selective media containing amoxicillin, pristinamycin, spiramycin, metronidazole, and spiramycin plus metronidazole.

RESULTS

In the majority of cases (19/26), the flora found in an anaerobic atmosphere predominated. Obligate anaerobes were present in 21 of the 26 samples. The bacteria most commonly detected were alpha-hemolytic streptococci (26/26) and the genera Prevotella (15/26), Veillonella (15/26), Bacteroides (9/26), and Capnocytophaga (9/26). Amoxicillin and pristinamycin were the most active in reducing the anaerobic cultivable counts. beta-Lactamase-producing strains were detected in 9 samples and were mostly bacteria of the genera Prevotella, Staphylococcus, and Bacteroides.

CONCLUSIONS

These results highlight (1) the diversity of the microflora associated with pericoronitis and the importance of the anaerobic flora and (2) the existence of selection pressure related to the use of beta-lactams that may culminate in failure of prescribed penicillins.

Actinobacillus actinomycetemcomitans serotype b lipopolysaccharide mediates coaggregation with Fusobacterium nucleatum

Purified Actinobacillus actinomycetemcomitans serotype b lipopolysaccharide (LPS) was found to be able to bind Fusobacterium nucleatum cells and to inhibit binding of F. nucleatum to A. actinomycetemcomitans serotype b. Sugar binding studies showed that the requirements for binding of A. actinomycetemcomitans serotype b LPS to the F. nucleatum lectin are the presence of a metal divalent ion, an axial free hydroxyl group at position 4, and free equatorial hydroxyl groups at positions 3 and 6 of D-galactose, indicating that the beta-N-acetyl-D-galactosamine in the serotype b LPS trisaccharide repeating unit is the monosaccharide residue recognized by the F. nucleatum lectin. These data strongly suggest that A. actinomycetemcomitans serotype b LPS is one of the receptors responsible for the lactose-inhibitable coaggregation of A. actinomycetemcomitans to fusobacteria.

Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus in systemic and nonoral infections in Finland

The oral cavity is the ecological niche for Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus, but occasionally they cause severe nonoral infections. In this study we present 20 systemic or nonoral infections due to A. actinomycetemcomitans and H. aphrophilus, comprising all isolates of these species forwarded to and stored in Finnish reference laboratories during the years 1988-2000. The time from specimen collection to correct species identification was 9.3 days for A. actinomycetemcomitans and 10.7 days for H. aphrophilus. A. actinomycetemcomitans strains represented serotypes a, b, c, and d. Arbitrarily primed PCR distinguished four A. actinomycetemcomitans and six H. aphrophilus genotypes. Antimicrobial susceptibility testing with benzylpenicillin, amoxicillin, tetracycline, metronidazole, azithromycin, and trovafloxacin showed generally good activities against the present strains, and the susceptibility patterns closely resembled those of oral strains. The prolonged time to recover and identify A. actinomycetemcomitans and H. aphrophilus from systemic and nonoral infections may delay the correct diagnosis of the patient, but the good antimicrobial efficacies of antimicrobial agents against these pathogens give a good prognosis for the patients and advance the treatment of severe infections caused by these fastidious organisms of oral origin.

The effects of a new mouthrinse containing chlorhexidine, cetylpyridinium chloride and zinc lactate on the microflora of oral halitosis patients: a dual-centre, double-blind placebo-controlled study

AIM

This study evaluated the microbial effects of a newly formulated mouthwash (Halita) on oral halitosis patients.

METHODS

Forty subjects were included in this dual-centre, double-blind, placebo-controlled parallel study. Inclusion and exclusion criteria were used to select patients. At baseline and at 2 weeks post-treatment, full-mouth organoleptic odor scores, level of volatile sulphur compounds (VSC) and the Winkel Tongue Coating Index were recorded. Standardized samples of tongue coating, saliva and subgingival plaque were microbiologically investigated. Participants were randomly assigned to the test or placebo groups.

RESULTS

High prevalences were observed for Fusobacterium nucleatum, Prevotella intermedia and Porphyromonas gingivalis in tongue coating, saliva and subgingival plaque samples. A significant positive correlation between baseline total counts of P. gingivalis in saliva samples and organoleptic and VSC scores was found. Two weeks post-treatment there was a reduction in total anaerobic counts in all samples in the test group. A significant positive correlation was observed between the reduction in total counts in saliva samples and the reduction in organoleptic scores in the test group. Significant reductions in total counts and proportions of F. nucleatum and total counts of P. intermedia in tongue coating samples were observed in the test group.

CONCLUSIONS

The test mouthwash demonstrated efficacy in reducing the microbiological parameters in three oral niches in moderate to severe halitosis patients without periodontitis, and this was correlated with the improvements in organoleptic and VSC scores but not with the tongue coating scores.

Can toothpaste or a toothbrush with antibacterial tufts prevent toothbrush contamination?

BACKGROUND

Periopathogens and cariogenic species survive more than 48 hours on toothbrushes even under dry storage. This study examined a decontamination of toothbrushes by means of the bactericidal effect of different toothpastes or a special coating of the tufts.

METHODS

Eight untreated periodontitis patients were professionally brushed, using a new toothbrush per quadrant and 3 different toothpastes containing either amine/stannous fluoride (AmF/SnF2), amine fluoride (AmF), or a mild surfactant as major antibacterial component (excipient), or no paste (C). The brushes were rinsed and stored dry at room temperature. At different time intervals, 4 tufts per toothbrush were processed for selective and non-selective culturing procedures. The protocol was repeated comparing AmF/SnF2 and C with 2 toothbrushes with coated tufts (coat1 and coat2).

RESULTS

At baseline, C brushes (n = 16) harbored 10(7), 10(8), and 10(6) colony forming units (CFU) of aerobic, anaerobic, and black pigmented species, respectively. After 24 hours 10(6) CFU of aerobic and anaerobic species could still be cultured from 14 of the 16 brushes. Black-pigmented species remained detectable up to 4 hours; detection frequencies for Fusobacterium nucleatum and Streptococcus mutans at 24 hours were 5/16. With AmF/SnF2 and AmF toothpaste the number of adhering bacteria was already 2 log lower at baseline (P<0.05), but not for the excipient (0.5 log, P = 0.7). With AmF/SnF2 no vital species could be detected after 8 hours. AmF reduced the bacterial survival rate significantly more than the excipient, but less than AmF/SnF2 (P<0.05). The bactericidal effect of coat1 and coat2 was negligible when compared to C (P>0.20), and clearly inferior to the AmF/SnF2 paste (P<0.0001). After 24 hours these brushes still harbored >10(5) CFU.

CONCLUSIONS

Toothpastes can significantly reduce contamination of toothbrushes, but their bactericidal activity is dependent on their composition. Coated tufts failed to limit the bacterial contamination.

Change of antibiotic susceptibility following periodontal therapy. A pilot study in aggressive periodontal disease

BACKGROUND

The hypothesis was tested that bacterial susceptibilities in aggressive periodontitis change upon administration of systemic antibiotics as adjuncts to periodontal therapy.

METHODS

In 23 subjects (average age 38.9+/-6.7 years) with aggressive periodontitis, microbial parameters were assessed prior to and 1 year after completion of comprehensive mechanical/surgical and systemic antimicrobial therapy. Following identification of five selected pathogens with the Rapid ID 32 A system, their susceptibilities towards amoxicillin/clavulanate potassium, metronidazole, and tetracycline were examined with the E-test. Antibiotics were administered according to the test results, and the minimal inhibitory concentrations (MIC90) were reevaluated after 1 year. Statistical analysis was performed on a patient basis, with the site data used for evaluation of the MIC levels.

RESULTS

Bacterial MIC levels remained constant among the three antibiotic treatment groups compared with baseline. Mean MIC90 values ranged from <0.02 to 0.11 microg/ml (amoxicillin/clavulanate potassium), <0.02 to 0.27 microg/ml (metronidazole), and <0.02 to 0.11 microg/ml (tetracycline). Observed changes in susceptibility were attributed to the elimination of single bacterial taxa in the subgingival environment after antibiotic therapy. There were no statistically significant differences in clinical parameters among the treatment groups. Single tetracycline MICs were 1.5- to 6-fold enhanced compared to amoxicillin/clavulanate potassium and metronidazole.

CONCLUSION

The periodontal pathogens investigated prior to and 1 year after periodontal therapy are tested sensitive to the antimicrobial agents. In aggressive periodontitis, changes in bacterial susceptibility upon the administration of systemic antibiotics are associated with the limited number of isolates tested following therapy.

The microflora recovered from the outer-surfaces of the Frialit-2 implanto-prosthetic connector

The aim of the present investigation was to examine the outer-surface microbiota of the prosthetic connector of Frialit-2 implants, and to compare the microbial findings with the peri-implant parameters 2 years after functional loading. In 16 implant-treated patients (55.8 +/- 9.5 years) the outer-surface micro-organisms of the prosthetic connectors were determined in 32 Frialit-2 implants. The functional loading time of the prosthetic suprastructures was 24.1 +/- 13.8 months on average. After removal of the implant-supported restoration, microbial samples were obtained from the outer-surfaces of the Frialit-2 prosthetic connector. The microbial plaque samples were specified on CDC-blood agar as percentages of the total cultivable flora. Actinobacillus actinomycetemcomitans was semiquantitively determined on TSBV-agar in CFU/ml. The microbial plaque samples were dominated by Actinomyces israelii (68.8%), Eubacterium lentum (56.3%) and Veillonella parvula (43.8%) with proportions ranking between 3.9% (V. parvula) and 11.1% (A. israelii). The most frequently detected gram-negative microorganisms were Fusobacterium nucleatum (87.5%), Porphyromonas gingivalis (81.3%), and Peptostreptococcus micros (68.8%) with enhanced proportions for P. gingivalis (11.4%) and P. micros (11.4%). No statistical significant correlation could be established between the microbiota present on the outer-surfaces of the F2-connector and the peri-implant parameters examined. The outer-surface microflora recovered from the implanto-prosthetic-connector of Frialit-2 implants reveals a colonization with gram-positive bacteria and potentially harmful gram-negative micro-organisms that were frequently detected, but present at low levels. After 2 years of restorative loading, the outer-surface microbial colonization is compatible with peri-implant soft tissue health.

A split-mouth study on periodontal and microbial parameters in children with complete unilateral cleft lip and palate

BACKGROUND

Complete unilateral cleft lip and palate (UCLP) is a hereditary or multifactorial malformation that can be corrected successfully with a combined orthodontic, surgical and restorative treatment. Such multidisciplinary treatment takes many years and demands a lot of attention to both patients' teeth and periodontium.

OBJECTIVES

This split-mouth study aimed to compare the periodontal health as well as the microbial parameters between cleft and non-cleft region.

MATERIAL AND METHODS

75 patients (52 males, 23 females) between 8 and 20 years with a complete unilateral cleft lip and palate (before (n = 30), during (n = 34) and after (n = 11) the active orthodontic treatment) volunteered for this study. Four regions were defined for the split-mouth comparison: teeth neighbouring cleft (site 1), tooth in cleft (site 2), and the corresponding contra-lateral teeth, respectively, in the unaffected quadrants (sites 3 and 4). At all sites the following periodontal parameters were recorded: plaque and gingivitis indices, pocket depth, attachment loss, bleeding on probing, tooth mobility (visual and Periotest), radiographic bone loss and gingival width. In addition, three pooled subgingival plaque samples were taken (around tooth in cleft, teeth facing the cleft, and contra-lateral teeth of the latter).

RESULTS

The differences between the teeth neighbouring the cleft and the corresponding contra-lateral opponents were of borderline significance (P <or= 0.05) for the plaque index, the approximal probing depths and the attachment loss (teeth facing the cleft always had slightly higher parameters). When the tooth in the cleft was compared to the contra-lateral tooth, differences were only found for both the approximal probing depths, attachment loss and bone loss, which were significantly higher for the tooth in the cleft. The microbial analysis did not reveal differences between the different sites, neither in the proportion of aerobic and anaerobic bacteria (differences < 0.5 log), nor in the detection frequency of periopathogens.

CONCLUSIONS

These data indicate that the periodontium in UCLP patients can cope well with a long-term orthodontic treatment, even in unfavourable conditions (like absence of attached gingiva and poor oral hygiene).

Dental biofilms at healthy and inflamed gingival margins

OBJECTIVES

The increased plaque formation observed in gingival inflammation is not fully understood. Receptor proteins in the dental pellicle might influence bacterial adhesion and subsequent plaque formation. The purpose of the present study was to examine proteins and microorganisms in dental biofilms, at healthy and inflamed gingival margins.

MATERIAL AND METHODS

To see whether marginal inflammation affects the composition of the pellicle and the early dental plaque, samples were taken from the gingival and incisal parts of teeth in periodontally healthy subjects, both in gingival health and during experimental gingivitis. Pellicle proteins were analysed using gel-electrophoresis, immunoblotting and image analysis. Bacteria were analysed by culturing and the PCR technique.

RESULTS

During gingivitis, the rate of plaque formation increased significantly. The semiquantitative amounts of proteins and the numbers of bacteria varied considerably between individuals and surfaces. The amount of total and individual pellicle proteins and the total numbers of bacteria were, however, increased during gingivitis and the increase in proteins was statistically significant on the incisal parts of tooth surfaces. Compared to a healthy gingiva, reduced numbers for Actinomyces spp. (incisal parts only) and streptococci and increased numbers of periodontopathogens in the 4 h dental biofilms were seen at the inflamed gingiva.

CONCLUSION

Increased gingival crevicular fluid flow during gingivitis affects pellicle formation and increased plasma proteins in the pellicle may modify bacterial attachment and early dental plaque composition.

Porphyromonas gingivalis, Bacteroides forsythus and other putative periodontal pathogens in subjects with and without periodontal destruction

BACKGROUND AND AIMS

Bacteria play an essential role in the pathogenesis of destructive periodontal disease. It has been suggested that not all bacteria associated with periodontitis may be normal inhabitants of a periodontally healthy dentition. In particular, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans have been isolated infrequently from subjects without periodontitis. The aim of the present study was to compare prevalence and proportions of a number of periodontal bacteria in periodontitis patients and control subjects.

MATERIAL AND METHODS

In all, 116 consecutive subjects diagnosed with moderate to severe periodontitis (mean age 42.4) and 94 subjects without radiographic evidence of alveolar bone loss (mean age 40.4) were recruited for the study. The gingival condition in the control group varied between gingival health and various degrees of gingivitis. In patients, the deepest pocket in each quadrant was selected for microbiological sampling. In control subjects all mesial and distal sites of all first molars were selected for sampling. All paper points from a patient were pooled and processed for anaerobic cultivation within 6 h after sampling. Clinical variables of sampled sites included bleeding index, probing pocket depth and clinical attachment level.

RESULTS

A. actinomycetemcomitans, P. gingivalis, Prevotella intermedia, Bacteroides forsythus, Fusobacterium nucleatum and Peptostreptococcus micros were significantly more often prevalent in patients than in controls. The highest odds ratios were found for P. gingivalis and B. forsythus (12.3 and 10.4 resp.). Other odds ratios varied from 3.1 to 7.7 for A. actinomycetemcomitans and P. micros, respectively. Absolute numbers of target bacteria were all higher in patients, but only the mean percentage of B. forsythus was significantly higher in patients in comparison to controls (P < 0.001).

CONCLUSIONS

A. actinomycetemcomitans, P. gingivalis, P. intermedia, B. forsythus, F. nucleatum and P. micros are all significant markers for destructive periodontal disease in adult subjects. Based on calculated odds ratios, B. forsythus and P. gingivalis are the strongest bacterial markers for this disease and are infrequently cultured from subjects without periodontal bone loss.

Actinobacillus actinomycetemcomitans induces apoptosis of T lymphocytes by the Fas and Fas ligand pathway

Actinobacillus actinomycetemcomitans expresses a number of toxins capable of inducing apoptotic cell death of T lymphocytes. However, the exact mechanism(s) has not been elucidated. The present study investigated the involvement of the Fas (CD95)-mediated apoptotic pathway in A. actinomycetemcomitans-induced T-cell apoptosis. To that end, peripheral blood mononuclear cells (PBMC) were cultured with or without A. actinomycetemcomitans cell-free culture supernatant (CFCS) for 0-96 h. The cells were then labeled with specific monoclonal antibodies and flow cytometry was performed. Results demonstrated up-regulation of Fas and activation of caspase-3 in T cells in response to A. actinomycetemcomitans CFCS. Monocytes were the only cells analyzed to express Fas ligand (FasL) constitutively, and this was further up-regulated in response to A. actinomycetemcomitans CFCS, while T cells expressed FasL only after this stimulation. Depletion of monocytes prior to stimulation with A. actinomycetemcomitans CFCS led to a marked decline in apoptosis. Blocking of Fas-FasL interactions with anti-Fas monoclonal antibody or Fas:Fc fusion protein lead to a significant decline, but not abolition, of T-cell apoptosis. Nearly all T cells expressed Bcl-2 at the outset of culture, and Bcl-2 expression declined in T cells stimulated with A. actinomycetemcomitans CFCS. Collectively, these data provide evidence for the induction of T-cell apoptosis by A. actinomycetemcomitans via the Fas-mediated pathway, involving caspase-3 and Bcl-2. Moreover, this apoptotic response was dependent on the presence of monocytes.

Two-part implants inserted in a one-stage or a two-stage procedure. A prospective comparative study

OBJECTIVE

The aim of this study was to evaluate the feasibility of using a two-part implant system in a one-stage procedure and to monitor the microflora in the peri-implant area in relation to clinical and radiographic outcome.

MATERIAL AND METHODS

After randomisation, 40 edentulous patients (Cawood & Howell class V-VI) received two IMZ implants in the anterior mandible inserted by either a one-stage (n = 20) or a two-stage (n = 20) surgical procedure for overdenture treatment. A standardised clinical and radiographic evaluation was performed after denture insertion as well as 6 and 12 months thereafter. Twelve months after loading, peri-implant samples were collected and analysed for the presence of putative periodontal pathogens using culture technique.

RESULTS

No striking differences were found between the two groups with regard to the clinical parameters during the evaluation period. The mean bone loss in the first year of functioning was 0.6 mm in both groups. With regard to the gingiva score, plaque score, bleeding score or bone loss between T0 and T12, no associations were found with the presence of the cultured microorganisms. An association was present between pockets >or= 4 mm and the presence of Peptostreptococcus micros in the two-stage group.

CONCLUSIONS

The short-term results indicate that two-part implants inserted in a one-stage procedure may be as predictable as inserted in the common two-stage procedure. The peri-implant sulcus can and does harbour potential periodontal pathogens without significant signs of tissue breakdown.

Local antimicrobial therapy after initial periodontal treatment

AIM

The aim of this single-blind, randomized, parallel-designed clinical trial (RCT) was to evaluate the clinical and microbiological effects of three sustained-release biodegradable polymers delivered into periodontal pockets following initial periodontal therapy.

METHODS

Forty-seven patients (28 females and 19 males) with a mean age of 51 years (range 29-71) underwent a periodontal examination at baseline (i.e. Week 0) and after 18 weeks. This included the assessment of the Plaque Index (PlI), Bleeding on Probing (BOP), Pocket Probing Depths (PPD) and Probing Attachment Levels (PAL) at six sites per tooth. Two to 4 months prior to baseline, all subjects had received initial periodontal therapy including motivation, instruction in oral hygiene practices and full-mouth scaling and root planing. At the treatment appointment (i.e. Week 2), the patients were randomly assigned to receive either Atridox trade mark, Elyzol Dental Gel or PerioChip at all residual periodontal pockets with a probing depth >/= 5 mm and concomitant BOP. In accordance with the manufacturer's recommendations, Elyzol Dental Gel was applied for a second time 7 days later. In addition to the clinical evaluation, subgingival microbiological samples were collected prior to treatment (i.e. Week 2) and at Weeks 4 and 18. Analysis of variance/covariance was used to evaluate changes from baseline to Week 18 for the clinical parameters.

RESULTS

Between the baseline and 18-week examinations, subjects treated with Atridox showed a significantly greater gain in mean PAL of 0.33 mm +/- 0.09 (SD) than subjects treated with Elyzol Dental Gel [0.03 mm +/- 0.09 (SD)](p = 0.03). However, the gain in PAL of 0.16 mm +/- 0.10 (SD) found after PerioChip application did not differ significantly from that obtained following the application of Atridox(p = 0.27). Of the sites treated with Atridox, 42% gained >/= 1 mm PAL and 9% >/= 2 mm PAL as opposed to the sites treated with Elyzol Dental Gel, in which 34% gained >/= 1 mm PAL and 8% gained >/= 2 mm PAL. Of the sites treated with PerioChip, 36% gained >/= 1 mm and 6% gained >/= 2 mm PAL following a completed initial periodontal therapy.

CONCLUSIONS

The application of the three biodegradable sustained release devices tested following initial periodontal therapy resulted in a statistically significant gain in mean PAL for AtridoxTM and a significant reduction in PPD for all three devices during the study period. Furthermore, when sites treated with Atridox were compared with sites treated with Elyzol, a significant difference in mean PAL gain (0.3 mm) was observed.

Local antibiotic therapy guided by microbiological diagnosis

BACKGROUND

The aim of this study was to determine the distribution patterns of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in periodontitis patients after standard mechanical periodontal therapy, and to evaluate the effect of additional local antibiotic therapy, given to all teeth with cultural evidence of these bacteria.

METHODS

17 patients were included. 852 separate subgingival microbial samples were taken from the mesial and distal aspect of every tooth in 17 subjects at baseline. 46 of these samples, from 10 positive subjects, showed cultural evidence for P. gingivalis. 82 samples, from 5 subjects, were A. actinomycetemcomitans-positive. Three subjects showed no evidence for persistence of A. actinomycetemcomitans or P. gingivalis. In the other 14 subjects, all A. actinomycetemcomitans- or P. gingivalis-positive teeth were treated with tetracycline fibers (ACTISITE(R)). Sub-gingival microbial samples were again taken from two sites of every tooth, 1 month after fiber removal. 89% of the initially P. gingivalis-positive sites were now negative, but 16 previously negative sites now tested positive. 77% of the initially A. actinomycetemcomitans-positive sites were now negative, but 5 previously negative sites now tested positive. The teeth with persisting P. gingivalis or A. actinomycetemcomitans were again treated with fibers. Two sites of every tooth were once more sampled after 1 month. At this time, 5 subjects still showed cultural evidence of P. gingivalis at a total of 19 sites, and 4 subjects were positive for A. actinomycetemcomitans in a total of 27 sites. These 9 patients were finally submitted to systemic antibiotic therapy (3 x 250 mg metronidazole plus 3 x 375 mg amoxicillin/d for 7 days). Despite of all efforts, P. gingivalis was again detected 3 months later in isolated sites in 3 subjects, and A. actinomycetemcomitans could be cultivated from one single site.

CONCLUSIONS

Therapy with tetracycline fibers guided by microbiological diagnosis effectively reduced P. gingivalis and A. actinomycetemcomitans locally, but was unable to completely eradicate the target organisms. Additional systemic antibiotic therapy further reduced P. gingivalis and A. actinomycetemcomitans. The observed persistence patterns suggest that reemergence of A. actinomycetemcomitans was due to recolonization, whereas the strikingly reproducible local reemergence of P. gingivalis in some sites indicated failed eradication.

Two-stage IMZ implants and ITI implants inserted in a single-stage procedure. A prospective comparative study

The aim of this study was to evaluate the feasibility of using a two-stage implant system in a single-stage procedure and to study the impact of the microgap at crestal level and to monitor the microflora in the peri-implant area. Forty edentulous patients (Cawood & Howell class V-VI) participated in this study. After randomisation, 20 patients received two IMZ implants inserted in a single-stage procedure and 20 patients received two ITI implants. After 3 months, overdentures were fabricated, supported by a bar and clip attachment. A standardised clinical and radiographic evaluation was performed immediately after denture insertion and 6 and 12 months later. Twelve months after loading, peri-implant samples were collected with sterile paper points and analysed for the presence of putative periodontal pathogens using culture techniques. One IMZ implant was lost due to insufficient osseointegration. With regard to the clinical parameters at the 12 months evaluation, significant differences for plaque score and probing pocket depth (IMZ: mean 3.3 mm, ITI: mean 2.9 mm) were found between the two groups. The mean bone loss in the first year of functioning was 0.6 mm for both groups. Prevotella intermedia was detected more often in the ITI group (12 implants) than in the IMZ group (three implants). Porphyromonas gingivalis was found in three patients. In one of these patients an implant showed bone loss of 1.6 mm between T0 and T12. Some associations were found between clinical parameters and the target microorganisms in the ITI group. These associations were not present in the IMZ group. The short-term results indicate that two-stage implants inserted in a single-stage procedure may be as predictable as one-stage implants. The microgap at crestal level in nonsubmerged IMZ implants seems to have no adverse influence on the peri-implant microbiological colonisation and of crestal bone loss in the first year of functioning. The peri-implant sulcus can and does harbour potential periodontal pathogens without signs of peri-implantitis during the evaluation period of 1 year.

In vitro antimicrobial susceptibility of oral strains of Actinobacillus actinomycetemcomitans to seven antibiotics

BACKGROUND/AIMS

Periodontal infections with Actinobacillus actinomycetemcomitans seem to be refractory to conventional therapy. The aim of the present study was to test the in vitro susceptibilities of A. actinomycetemcomitans strains to a panel of seven orally administrable antibiotics.

METHODS

A total of 60 isolates of A. actinomycetemcomitans recovered from 43 individuals with gingivitis or periodontitis were tested. In addition, laboratory strains UP-6 and JP2 were analysed. The E-test was employed in order to determine minimal inhibitory concentrations (MIC) of antibiotics ampicillin/sulbactam, roxithromycin, azithromycin, doxycycline, metronidazole, ciprofloxacin, and moxifloxacin.

RESULTS

A. actinomycetemcomitans was highly susceptible to both fluoro-quinolones (MIC90 of 0.006 microgram/mL of ciprofloxacin and 0.032 microgram/mL of moxifloxacin). Good susceptibilities were found for ampicillin/sulbactam and doxycycline (MIC90 of 0.75 microgram/mL and 1 microgram/mL, respectively), and moderate susceptibilities for azithromycin (MIC90 of 3 microgram/mL). Most strains were resistant to metronidazole and roxithromycin. Cluster analysis revealed two larger clusters of A. actinomycetemcomitans strains with the smaller cluster assembling isolates with significantly higher MICs of most antibiotics.

CONCLUSIONS

Due to reported favourable pharmacokinetics, the fluoro-quinolone moxifloxacin appeared to be a promising candidate for adjunctive systemic antibiotic therapy in periodontal infections with A. actinomycetemcomitans.

Comparison of microbial cultivation and a commercial PCR based method for detection of periodontopathogenic species in subgingival plaque samples

OBJECTIVES

Microbiological laboratory procedures are involved in diagnosis and therapy control of progressive and refractory forms of periodontitis. In recent years techniques have been developed based on the detection of nucleic acids. The purpose of this study was to validate the commercially available micro-Dent(R) test which employs probes for A. actinomycetemcomitans, P. gingivalis, P. intermedia, B. forsythus and T. denticola.

METHODS

122 plaque samples obtained from periodontal pockets with various depths from 33 early onset periodontitis (EOP) patients and 15 periodontally healthy subjects were analysed by cultivation and the microDent(R) kit.

RESULTS

Both cultivation and the nucleic acid based assay showed a positive correlation of pocket depth with the frequency and quantity of periodontopathogenic species. T. denticola was found only in pockets > 4 mm in EOP patients. Comparison of the two methods revealed that the microDent(R) kit identified both P. gingivalis and B. forsythus more often than did the cultivation method.

CONCLUSIONS

Nucleic acid techniques should replace cultivation methods as gold standard in microbiological diagnosis of progressive periodontitis. The micro-Dent(R) kit can be recommended for microbiological laboratories analysing subgingival plaque samples.

Attachment loss in Moroccan early onset periodontitis patients and infection with the JP2-type of Actinobacillus actinomycetemcomitans

BACKGROUND

A clone of Actinobacillus actinomycetemcomitans (JP2) with increased leukotoxin production and characterized by a 530-bp deletion in the leukotoxin gene operon is endemically present in Morocco and strongly associated with the presence of early onset periodontitis (EOP).

OBJECTIVES

To compare patterns of attachment loss among EOP-patients with or without JP2-type of A. actinomycetemcomitans in dental plaque.

MATERIAL AND METHODS

Among 45 Moroccan adolescents with EOP (i.e. one or more teeth with attachment loss >/= 3 mm) 39 had cultivable plaque samples. Fifteen (38.5%) were culture-positive for A. actinomycetemcomitans of the JP2-type as determined by PCR, and 24 (61.5%) were not (mean age 16.5 years in both groups).

RESULTS

EOP-patients culture-positive for A. actinomycetemcomitans of the JP2-type had significantly more teeth with attachment loss (mean 5.1, median 4.0) than EOP-patients not culture-positive for A. actinomycetemcomitans of the JP2-type (mean 2.8 teeth, median 1.0) (p = 0.02), and higher attachment loss (mean 4.3 mm vs. 3.4 mm; median 4.0 mm vs. 3.0 mm) (p = 0.01). No major differences could be detected between the two groups in the pattern of affected teeth in the dentition.

CONCLUSIONS

The study demonstrates increased periodontal destruction among EOP-patients culture-positive for A. actinomycetemcomitans of the JP2-type compared with EOP-patients without the JP2-clone.

Natural transformation and DNA uptake signal sequences in Actinobacillus actinomycetemcomitans

Actinobacillus actinomycetemcomitans is a member of the family Pasteurellaceae and a major causative agent of periodontitis. While several genera from this family are known to be competent for transformation, A. actinomycetemcomitans has yet to be fully characterized. Here we show that the competence of A. actinomycetemcomitans is remarkably similar to that of Haemophilus influenzae. In addition to having a similar frequency of transformation as H. influenzae, A. actinomycetemcomitans competence could also be induced at least 100-fold by cyclic AMP, suggesting that, as in H. influenzae, at least some competence genes are regulated by catabolite repression. Even more intriguing was the discovery of a putative A. actinomycetemcomitans DNA uptake signal sequence (USS) virtually identical to the USS of H. influenzae. Moreover, we provide evidence that this sequence functions in the same capacity as that from H. influenzae; the sequence appears to be required and sufficient for DNA uptake in a variety of assays. Finally, we have taken advantage of this system to develop a simple, highly efficient competence-based method for generating site-directed mutations in the wild-type fimbriated A. actinomycetemcomitans.

Actinobacillus actinomycetemcomitans in a rural adult population in southern Thailand

The prevalence of Actinobacillus actinomycetemcomitans isolates was examined in a rural population of southern Thailand. Sixty individuals aged 30-39 and 50-59 years were randomly selected from a group of 363 persons, living in four villages, who had been clinically examined previously. A subgingival plaque sample was taken with a curette from the mesial aspect of the two upper and lower first molars. Each sample was dispersed in 3.3 ml of VMGA III transport medium and spread onto Trypticase Soy Broth with Bacitracin and Vancomycin (TSBV)-agar plates on the same day. After incubation in 10% CO2 for 5 days the plates were examined for typical A. actinomycetemcomitans colonies which were tested for catalase activity. Each strain was further tested for biochemical characteristics, serotyped against serotype-specific antisera a-e and ribotyped after DNA digestion using the restriction endonucleases HindIII and EcoRI. For 53 (88%) of the 60 individuals, A. actinomycetemcomitans was present in at least one subgingival sample, which is considerably higher than the prevalence in Western European adults. In 11 individuals, two or three different strains were found. Serotypes a and c were the most prevalent, and serotype b was found only once among 46 tested isolates. Eleven ribotypes were found among the 46 strains. While the same ribotype could be found among individuals of the same village, no ribotype of A. actinomycetemcomitans was unique for individuals of any one village. The study demonstrated a high prevalence of A. actinomycetemcomitans among adults of the rural population of southern Thailand and indicates that this species is present as part of the resident oral flora in this population.

Actinobacillus actinomycetemcomitans proportion of subgingival bacterial flora in relation to its clonal type

We investigated whether certain Actinobacillus actinomycetemcomitans clones occur in elevated proportions in subgingival flora, and if the proportions relate to other bacteria in the samples. A total of 121 A. actinomycetemcomitans strains from 121 patients with periodontitis were serotyped and 60 strains were also genotyped. The 121 strains were divided into three groups and the 60 strains into two groups according proportion of A. actinomycetemcomitans. The samples from the 60 patients with genotyped strains were cultured for five other species. Among the 121 strains, serotype b occurred significantly more frequently in the high- (n = 14, proportions > 5%, mean = 18.09, SD = 20.07%) than low- (n = 49, proportions < or = 0.1%), mean = 0.04, SD = 0.03%) or intermediate-proportion groups (n = 58, proportions > 0.5%, mean = 1.31, SD = 1.24%). Genotype 3 occurred significantly more frequently in samples with low A. actinomycetemcomitans proportions (n = 28, < or = 0.1%, mean = 0.04, SD = 0.03%) than in those with high proportions (n = 32, > 0.1%, mean = 5.70, SD = 14.60%). No differences were seen in the detection frequencies or proportions of the five bacterial species between the samples with low or high A. actinomycetemcomitans proportions. The results indicate that certain clonotypes of A. actinomycetemcomitans may preferentially occur as low proportions, suggesting their controlled growth. Conversely, some serotype b clones may have a competitive advantage in subgingival flora.

Lactoferrin iron levels affect attachment of Actinobacillus actinomycetemcomitans to buccal epithelial cells

BACKGROUND

Prior reports have suggested that the iron-binding protein lactoferrin (LF) may either kill Actinobacillus actinomycetemcomitans (Aa) or interfere with its binding to host cells. Other studies have indicated that the degree of iron saturation of LF might play a role in these interactions. However, these studies utilized strains that had lost critical attachment characteristics found in well-preserved clinical isolates of Aa. The purpose of this work was to study the effect of LF iron levels on survival and attachment of well-preserved clinical isolates of Aa.

METHODS

LF containing 0%, 30%, and 100% iron saturation was tested for its ability to kill clinical isolates of Aa and to inhibit their binding to buccal epithelial cells (BECs).

RESULTS

Neither iron-free LF (apo-LF) nor iron-saturated LF killed Aa clinical isolates. Increasing the iron saturation of LF resulted in an increased inhibition of Aa binding to BECs (P < or =0.005). This effect was consistent for the 3 clinical isolates tested. Pretreatment of Aa with iron-saturated LF reduced binding to BECs by 58%, 61.8%, and 64.2%, respectively, for each of the 3 clinical strains tested (P < or =0.005). Pretreatment of Aa strains with apo-LF, iron alone, or bovine serum albumin had no effect on binding. Pretreatment of BECs with LF (either apo-LF or iron-containing LF) had no influence on Aa binding.

CONCLUSIONS

These results indicate that reduction in binding of Aa to epithelial cells is maximized by pretreatment of Aa cells with iron-saturated lactoferrin. These in vitro results suggest that patients with lactoferrin containing lowered levels of iron would be more susceptible to Aa colonization.

Adjunctive effects to non-surgical periodontal therapy of systemic metronidazole and amoxycillin alone and combined. A placebo controlled study

BACKGROUND AND AIM

Several studies have reported adjunctive benefits to scaling and root planing (SRP) of systemic amoxycillin and metronidazole in the treatment of periodontal diseases. To date no comparisons have been made of these antimicrobials alone or in combination. The aim of this study was to compare the adjunctive benefits to SRP of amoxycillin and metronidazole alone and combined.

METHODS

66 subjects <46 years of age with advanced chronic periodontal disease participated in this randomised, double blind, 4 parallel treatment group designed study. All subjects received quadrant SRP and then were prescribed amoxycillin capsules (250 mg) and metronidazole tablets (200 mg) (AM) or lactate capsules and metronidazole (PM) or amoxycillin and calcium lactate tablets (AP) or lactate and calcium lactate (PP). All medication was 3 of each per day for 7 days. Subgingival plaque samples were obtained and probing depth (PD), loss of attachment (LOA), bleeding on probing (BOP), suppuration (SUPP) and plaque (DEP) were recorded pre-treatment, 1, 3 and 6 months post-treatment.

RESULTS

Final group sizes were: AM=15, PM=16, AP=16 and PP=15. PD improved in all groups. Treatment effects were highly significantly different and always greatest in the AM and least in the PP groups. Benefits of PM and AP over PP were also noted. LOA improved in all groups and showed the same highly significant treatment differences, again favouring AM. BOP improved in all groups, particularly in AM compared to the other groups. SUPP improved in all groups and was virtually eradicated in AM with differences among treatments highly significant. DEP changed little in any group and there were no significant differences among groups. Microbiological data showed significant differences in favour of AM compared to PP and PM for total aerobes and anaerobes at 1 month. P. intermedia counts were always lower in active groups compared to PP and reached significance for AM and AP at 1 month and AM and PM at 3 months.

CONCLUSION

The significant differences among treatment groups and the overall trend in the data, in line with other studies, support the considerable adjunctive benefits to SRP of amoxycillin and metronidazole combined in the treatment of advanced chronic periodontal disease.

Antibacterial activity of Brazilian propolis and fractions against oral anaerobic bacteria

Propolis collected from a cerrado area in Minas Gerais State, Brazil, was subjected to chromatography on silica gel column and to partition between immiscible solvents. Propolis aqueous-ethanolic extract and fractions obtained were tested for inhibitory activity against periodontitis-causing bacteria. All of the assayed bacterium species were susceptible to propolis extract. The two fractionation methodologies yielded fractions which were active against bacteria, with minimum inhibitory concentrations (MIC) ranging from 64 to 1024 microg/ml. TLC and HPLC analyses of the extract and of active fractions showed the presence of phenolic compounds of varied polarity. None of the assayed fractions was more active than the extract, suggesting that the antibacterial activity is probably due to the synergistic effect of several compounds.

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.

Bacterial survival rate on tooth- and interdental brushes in relation to the use of toothpaste

BACKGROUND, AIMS

Previous studies indicated that oral hygiene aids can play a rôle in the intra-oral translocation of pathogens. The survival rate of cariogenic and periodontopathogenic species on toothbrushes, with and without toothpaste, and interdental brushes was presently investigated.

MATERIAL AND METHODS

12 periodontitis patients had their interdental spaces professionally cleaned with interdental brushes and their teeth with new toothbrushes with or without different dentifrices. Each time brushes were rinsed with tap water and stored dry at room temperature. At different time intervals an interdental brush or 4 tufts from a toothbrush were processed for vitality staining and selective and non-selective culturing procedures.

RESULTS

Immediately after rinsing, a toothbrush without toothpaste harboured 10(7), 10(8) and 10(7) colony forming units (CFU) of respectively aerobic, anaerobic and black pigmented species. An insignificant decrease occurred the first 24 hours and after 48 hours still 10(4) CFU of aerobic and anaerobic species could be cultured. No periodontopathogen remained detectable at 8 hours, except for Fusobacterium nucleatum. The proportion of vital bacteria decreased in 48 hours from 50% to 30%. Comparable results were obtained for interdental brushes. The bacterial survival rate on toothbrushes was significantly reduced by the use of a detergent containing toothpaste by 2 log at baseline, another 2 log at 4 hours and an extra log more at 8 hours for aerobic and anaerobic species. A toothpaste without detergent only had an insignificant bactericidal effect.

CONCLUSION

Toothpaste detergents decrease the survival rate of pathogenic species on a toothbrush and can thus limit the risk for bacterial translocation.

Papillon-Lefèvre syndrome: serum immunoglobulin G (IgG) subclass antibody response to periodontopathic bacteria. A case report

BACKGROUND

Papillon-Lefevre syndrome (PLS) is a rare autosomal recessive disorder which is characterized by palmar-plantar hyperkeratosis and rapid periodontal destruction of both primary and permanent dentitions. In this case report, we present clinical features, and microbiological and immunological findings of 40 month-old Thai male PLS patient.

METHODS

Microbiological examinations consisted of bacterial culture methods utilizing selective media, morphological identification, and biochemical tests. In addition, the specific serum IgG subclass antibody titers reactive with etiologic periodontal bacteria were determined by the dot-blot immunological analysis and enzyme linked immunosorbent assay (ELISA).

RESULTS

The examinations revealed that the patient harbored 3 major suspected periodontopathic microorganisms, A. actinomycetemcomitans, P. gingivalis, and P. intermedia. The patient's serum IgG1, IgG2, and IgG3, but not IgG4, titers against A. actinomycetemcomitans were dramatically increased. The predominant IgG subclass was IgG1. In contrast, the IgG titers against other tested bacteria, P. gingivalis, P. intermedia, and F. nucleatum, appeared to be similar to those of a healthy control.

CONCLUSIONS

A. actinomycetemcomitans seems to play a pivotal role in the bacteria-host interaction in PLS periodontal pathogenesis. Response of the specific serum IgG subclass antibody titers against the A. actinomycetemcomitans antigen has been demonstrated. This association warrants further investigation.

Some effects of non-surgical therapy on gingival inflammatory cell subsets in patients with early-onset periodontitis associated with Actinobacillus actinomycetemcomitans

BACKGROUND

Limited information is available as to whether local cellular immunity in early-onset periodontitis (EOP) subjects harboring Actinobacillus actinomycetemcomitans (Aa) differs from that in patients without Aa. In addition, the effect of scaling and root planing on various lymphocyte subsets is described rather sparsely.

METHODS

In 10 subjects with early-onset periodontitis harboring Aa (EOP-Aa) and in 10 subjects without Aa (EOP-nonAa), clinical measurements were recorded and gingival biopsies were performed before and after scaling and root planing. The specimens were cut into serial sections; using the alkaline phosphatase-antialkaline phosphatase technique, monoclonal antibodies to CD20 (B cells), CD30 (plasma cells), and CD45RO (T-memory cells) were applied as well as polyclonal antibodies to alpha, gamma, and mu chains (Ig A, G, and M). Cells were counted from an area of 0.25 mm2 in areas showing the largest infiltration.

RESULTS

Before therapy, mean counts of all cell phenotypes were found to be markedly enhanced in the EOP-Aa group compared to EOP-nonAa subjects. Following scaling and root planing, the numbers of all phenotypes decreased in both groups. However, comparing the data before and after therapy in the EOP-Aa group, the P value was <0.05 only for CD30-positive cells. In the EOP-nonAa group, the differences before and after therapy reached statistical significance (P<0.05) for all cell counts, except for IgM-positive cells. Furthermore, reduction of probing depth and gain of clinical attachment reached the 0.05 level of statistical significance only in EOP-nonAa subjects.

CONCLUSIONS

In EOP subjects harboring Aa, inflammatory cell subsets were detected in 2- to 3-fold higher numbers compared to patients without Aa. Scaling and root planing resulted in a decrease of all cell phenotypes studied in individuals without Aa, whereas in subjects with Aa, the only significant decrease that was seen occurred in plasma cells.

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.

Colonization and persistence of rough and smooth colony variants of Actinobacillus actinomycetemcomitans in the mouths of rats

Fresh isolates of Actinobacillus actinomycetemcomitans (Aa) bind avidly to surfaces in vitro, but existing in vivo studies of the adherence of Aa are limited. This study had two goals: (1) to compare the oral colonization of two isogenic strains of Aa-CU1010, a clinical isolate that expresses the adherent phenotype, and CU1012, a minimally adherent laboratory variant-and (2) to check for phenotypic reversion of these strains in a clinical setting. Rifampicin-resistant strains, developed for tracking in Sprague-Dawley rats, were tested in vitro to determine their stability and binding. In study 1, after antibiotic suppression, six rats (group I) received CU1010 in their feed. The eight rats in group II received CU1012 in their feed and four were supplemented by oral swabbing and four by gastric gavage. Group III consisted of three sham-inoculated controls. All rats were inoculated for 4 days. Microbiological data were collected at 1, 4 and 8 weeks after inoculation. Supporting data were supplied by antibody titres and clinical measures of alveolar bone loss. Study 2 consisted of six rats in each of three groups as above, but tagged strains of Aa were delivered by food alone. At all time-points in both studies, Aa was absent before inoculation and controls had no Aa or antibody to Aa. In study 1, all six rats in group I yielded positive cultures for Aa at 8 weeks. In group II, five of eight had positive cultures for Aa at 1 week, two of eight at 4 weeks and none had Aa at 8 weeks (P < or =0.001). All six rats in group I had serum anti-Aa titres compared to group II, where titres were seen in four of eight rats (P < or =0.015). In vitro data paralleled those found in vivo. No phenotypic reversion of either strain was seen in vivo. In study 2, four of six rats in group I showed Aa and had titres to Aa, while no other animals showed Aa at any time. The model provides convincing evidence that, unlike laboratory variants, clinical isolates colonize, persist and integrate into an already established, albeit reduced, econiche.

Aggressive periodontitis associated with Fanconi's anemia. A case report

BACKGROUND

Fanconi's anemia is an autosomal recessive disease associated with chromosomal breakage as well as pancytopenia, skin pigmentation, renal hypoplasia, cardiac defects, microcephaly, congenital malformations of the skeleton, hypogonadism, and increased risk of leukemia. The present report describes the periodontal clinical and microbiological status of an 11-year old male having Fanconi's anemia.

METHODS

Polymerase chain reaction analysis to detect human cytomegalovirus (HCMV), Epstein-Barr type 1 virus, and herpes simplex virus (HSV) was performed on paper-point samples pooled from either 3 periodontal sites with advanced attachment loss or 3 gingivitis sites with no clinical attachment loss. Anaerobic bacterial culture examination was performed on the pooled periodontitis sample.

RESULTS

The patient suffered from pancytopenia, allergy, asthma, hearing impairment, and mental retardation. Dentition consisted of 7 primary teeth, 11 erupted permanent teeth, and 14 unerupted permanent teeth. Most erupted teeth showed severe gingival inflammation with some gingival overgrowth and various degrees of periodontal attachment loss. Genomes of HCMV and HSV were detected in the pooled periodontitis sample and HCMV in the pooled gingivitis sample. The periodontitis sample but not the gingivitis sample revealed HCMV mRNA of major capsid protein, suggestive of active viral infection. The periodontitis sample also yielded Actinobacillus actinomycetemcomitans (1.1% of total isolates), FusobActerium species (7.9%), Campylobacter species (2.2%), Peptostreptococcus micros (3.4%), and Candida albicans (0.3%).

CONCLUSIONS

Oral features of Fanconi's anemia may include increased susceptibility to periodontitis. It is likely that underlying host defense impairment coupled with periodontal infection by HCMV and A. actinomycetemcomitans contribute to the severe type of periodontitis associated with Fanconi's anemia.

Absence of a specific subgingival microflora in adults with Down's syndrome

BACKGROUND

Periodontal disease in Down's syndrome (DS) is generally characterized by a high degree of bone loss. Bone loss of 5 mm or more is observed in 70% of these subjects. Among DS subjects, considerable differences in disease progression occur. So far, no studies have been conducted in which specific properties of the subgingival microflora have been related to the condition observed.

AIMS

To investigate (1) the subgingival microflora in DS subjects and other mentally retarded (control) individuals which were matched to the utmost and (2) to investigate the subgingival microflora of a "low-risk" and a " high-risk" group formed in DS subjects.

MATERIAL AND METHODS

17 DS subjects and 17 control subjects were matched with respect to age, plaque level and bleeding on probing. In addition, the DS group was divided in a "low-risk" group (0-2 teeth lost due to periodontal disease n=6) and a "high-risk"group (6-13 teeth lost due to periodontal disease n=11). Prevalence and proportions of the putative periodontal pathogens Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus, Peptostreptococcus micros, Fusobacterium nucleatum and Campylobacter rectus in the subgingival plaque were determined using anaerobic culture techniques. No differences in the prevalence of distinct suspected periodontopathic bacteria and bacterial subgingival composition between the DS group and the control group could be established. Also no differences in the prevalence of the seven investigated microbial species between the "low-risk" and the "high-risk" group were observed.

CONCLUSIONS

Because of the lack of differences in microflora between the DS group and the control group, a specific effect of the microbiological composition in the periodontal status of subjects with DS can be excluded in this population. Host factors constitute the more likely explanation of the differences observed in DS.