Subgingival microflora and periodontal disease

Clinical and microbiological effects of chlorhexidine and arginine sustained-release varnishes in the mentally retarded

Local applications of sustained-released varnishes of chlorhexidine and arginine were used in a controlled pilot study of 34 mentally retarded patients, ages 18-45, assigned to one of these groups: chlorhexidine (C), arginine (A), or placebo (P). A professional scaling followed by four weeks of professional brushing to reach a Plaque Index (PII) and Gingival Index (GI) of 1.0 at baseline preceded eight weeks of daily varnish application to the buccal and labial surfaces of all teeth. Clinical parameters (PII and GI) and bacterial samples from selected teeth were collected at predetermined intervals. Four and eight weeks following the baseline, the PII was significantly different among the groups, with the lowest score in the chlorhexidine group. No significant differences among the three groups were noted for the GI. The chlorhexidine and arginine groups showed significant reductions (p < 0.05 and p < 0.01, respectively) in the number of S. mutans. The arginine group showed a nonsignificant increase in the number of S. sanguis. These results suggest that the topical antimicrobial agents may have some relevance to plaque control among patients with mental retardation.

Use of a nonradioactive genetic probe identified, synthesized, and labeled in the polymerase chain reaction

This study introduces a strategy to identify and produce sequences useful as genetic markers, or native genetic probes for DNA-DNA hybridization in bacterial strains where the genetics is not well described. Actinobacillus actinomy-cetemcomitans (A.a.) was used as an example. Fifty ng genomic DNA from A.a. ATCC 33384 and Haemophilus aphrophilus ATCC 33389 was amplified in a thermocycler using a single 10-mer primer. The PCR products were separated by electrophoresis on a 1% submarine agarose gel containing ethidium bromide and visualized by UV illumination, and the strain-specific amplitypes were compared. DNA from two bands, 0.9 and 4 kb, unique for the A.a. strain, was cut out, amplified under high stringency with the same primer and labeled by replacing 33.3 microM dTTP with digoxigenin-labeled dUTP in the reaction mixture. The labeled probe was then repeatedly used for hybridization to DNA from various A.a., H. aphrophilus, and other bacterial strains of the Pasteurellaceae family. The results showed that the 0.9-kb probe detected all A.a. tested, and distinguished it from other closely related bacterial species. We conclude that the described strategy is useful for identifying and selecting genetic sequences useful as genetic markers in A.a.

Neutrophil defects as risk factors for periodontal diseases

There are several hypotheses proposed for the etiologic mechanisms causing periodontal diseases. These include a paradigm in which all individuals are equally susceptible to one or several pathogenic bacteria; a second paradigm that holds that all bacteria are equally virulent and that host susceptibility determines onset of disease; or a combination of the above. In this review, we analyze the role of neutrophil dysfunction as a risk factor for the onset of periodontitis. Both intrinsic or genetically inherited abnormalities of neutrophils and acquired neutrophil abnormalities are considered. While a large body of data implicates neutrophil dysfunction, either intrinsic or acquired (bacterially or extrinsically induced), as a significant risk factor for the periodontal diseases, clear, prospective, longitudinal epidemiologic studies to evaluate this association remain to be performed.

Diversity of cultivable and uncultivable oral spirochetes from a patient with severe destructive periodontitis

To determine the genetic diversity of cultivable and uncultivable spirochetes in the gingival crevice of a patient with severe periodontitis, partial 16S rRNA genes were cloned from PCR-amplified products of DNA and RNA extracted from a subgingival plaque sample. Approximately 500 bp were amplified in PCRs by using universally conserved primers with polylinker tails. Purified PCR products were cloned into Escherichia coli by using the plasmid vector pUC19. The resultant clone library was screened by colony hybridization with a radiolabeled, treponeme-specific oligonucleotide probe. The 16S rRNA inserts of 81 spirochetal clones were then sequenced by standard procedures. Sequences were compared with 16S rRNA sequences of 35 spirochetes, including the four known cultivable oral treponeme species. The analysis revealed an unexpected diversity of oral treponemes from a single patient. When 98% or greater sequence similarity was used as the definition of a species-level cluster, the clone sequences were found to represent 23 species. When 92% similarity was used as the definition, the clones fell into eight major groups, only two of which contained named species, Treponema vincentii and Treponema denticola, while Treponema pectinovorum and Treponema socranskii were not represented in any cluster. Seven of the 81 spirochetal clones were found to contain chimeric 16S rRNA sequences. In situ fluorescence hybridization with a fluorescein isothiocyanate-labeled oligonucleotide probe specific for one of the new species representing cluster 19 was used to identify cells of the target species directly in clinical samples.

Early-onset periodontitis in Hispanic-American adolescents associated with A. actinomycetemcomitans

This study examines the frequency of oral disease in an adolescent population, and assesses the relationship to Actinobacillus actinomycetemcomitans. A total of 470 eighth grade students from San Antonio, Texas, were examined clinically for number of teeth, frequency of gingival inflammation, frequency of sites with BOP, and frequency of sites with 3-5 mm pockets, and pockets > 5 mm. The population ranged in age from 12 to 17 yr and was 93% Hispanic. Heavy accumulations of plaque and calculus were frequently observed and were associated with gingival inflammation, as 95.6% of the students exhibited bleeding on probing, and 99.6% of the students presented with at least on quadrant of inflammation upon visual examination. Significantly, 25.7% of the students exhibited early-onset periodontitis (EOP) with 1.7% diagnosed as LJP. Many students exhibited substantial levels of plaque and calculus, but no clinical evidence of loss of attachment. Subjects with periodontitis (EOP or LJP) presented with elevated systemic IgG antibody to A. actinomycetemcomitans serotype b and subgingival plaque samples positive for the microorganism. These results describe the prevalence of EOP/LJP in an adolescent Hispanic population from South Texas. The findings support that A. actinomycetemcomitans may represent a pathogen in periodontitis and while oral health care may be poor, contact with the microorganism appears to be required to initiate disease in this population.

Infection by Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans, and antibody responses at different ages in humans

This study examined the serum IgG and IgM responses against Porphyromonas gingivalis and 3 serotypes of Actinobacillus actinomycetemcomitans, and the correlations of these responses with age and homologous infection. A total of 90 individuals were included in this study: 40 subjects with gingivitis, 40 periodontally healthy subjects, and 10 adult periodontitis subjects. The subjects in the gingivitis and periodontally healthy groups were divided into 4 stages based on their physiological age: early childhood, school age, puberty, and adult. In the gingivitis group, there was a positive correlation between increase in age and increase in serum IgG antibody levels against P. gingivalis until puberty. However, no statistically significant difference was found between the puberty stage and the adult stage. The average level of IgG antibodies against A. actinomycetemcomitans in the school age gingivitis group was significantly higher than that in the early childhood gingivitis group for all serotypes (p < 0.01). In serotype c, IgG antibody levels in the school age gingivitis group were significantly higher than in the early childhood gingivitis group or the adult gingivitis group (p < 0.01). With both P. gingivalis and A. actinomycetemcomitans, positive correlations between elevated IgG level and infections by these microorganisms were found in the puberty gingivitis and adult periodontitis groups.

DNA probe detection of periodontopathogens in advanced periodontitis

Species-specific DNA probes were used to determine the presence of Actinobacillus actinomycetemcomitans (A.a.), Porphyromonas (Bacteroides) gingivalis, Prevotella intermedia, Treponema denticola, Eikenella corrodens, Fusobacterium nucleatum, and Wolinella recta in subgingival plaque from deep pockets/sites of patients with advanced periodontitis. The subjects were 20 patients with severe adult periodontitis, 13 men and 7 women (mean age 45.6 +/- 6.7 yr). For each subject, 9-10 subgingival sites with the deepest probing depths from each quadrant were sampled by the paper point method, a total of 198 sites, with mean probing depth 7.2 +/- 1.6 mm and clinical attachment level 9.5 +/- 2.7 mm. A.a. was present in at least one site in 75% of the subjects; P. gingivalis was found in 95%; P. intermedia and W. recta were found in 90%, respectively; and T. denticola, E. corrodens, and F. nucleatum were found in all subjects. In the 198 samples, A.a. was detected in 25.8%, P. gingivalis in 51.5%, P. intermedia in 64.1%, T. denticola in 60.6%, E. corrodens in 72.9%, F. nucleatum in 74.7%, and W. recta in 65.7%. The predominant combination was the simultaneous presence of P. intermedia, T. denticola, E. corrodens, F. nucleatum, and W. recta in 89.5% of the subjects and 46.8% of the sites. Of these sites, 51.1% showed the combined presence of P. gingivalis and 28.4% that of both A.a. and P. gingivalis. None of the seven bacteria could be detected in 14.4% of the total sites sampled. The present study indicates that severe destructive adult periodontitis is a multibacterial infection and that certain combinations of periodontopathogens seem to be important in the pathogenesis of the disease.

The effect of systemic ibuprofen on gingival inflammation in humans

This clinical trial investigated the influence of short-term ibuprofen therapy on the early phase of the treatment of adult chronic periodontitis. The subjects were 17 patients in good general health referred for specialist periodontal treatment, having moderate chronic adult periodontitis. A series of assessments were made every 2 weeks over an 8-week period, including evaluations of oral hygiene, gingival inflammation and probing pocket depths. All participants received oral hygiene instruction, and following baseline examinations, had half the dentition, chosen at random, treated by scaling and root planing. The patients were randomly distributed into 2 groups, a test group receiving a 14-day course of 800 mg ibuprofen daily, in 4 divided doses, and a control group who did not receive any drug regime. At the 2-week assessment following the drug regime, significantly greater reduction in gingival bleeding, colour and pocketing was detected in the test compared with the control group. The beneficial effects were less evident thereafter. Although clinical application of the regime used in this study would not be justified by these results, further research into anti-inflammatory agents as an adjunct in the treatment of periodontal diseases could be considered, in the light of the beneficial effect on gingivitis in the early phase of periodontal treatment reported.

Specific antibodies against Actinobacillus actinomycetemcomitans in serum and saliva of patients with advanced periodontitis

The aim of the present study was to discover any possible correlation between specific antibodies against Actinobacillus actinomycetemcomitans (A.a.) in serum and saliva. The test group consisted of 38 patients aged 31-68 yr (mean 49) with advanced periodontitis. Twenty-nine subjects aged 23-67 yr, without periodontal destruction, formed a control group with a reference level of specific salivary antibodies against A.a. A subgingival plaque sample for culturing A.a., a specimen of stimulated whole saliva, and a sample of venous blood were taken from each subject of the test group. Specific IgG and IgA antibodies against A.a. were determined from serum and stimulated whole saliva by means of the ELISA test. Fifteen of the patients (39%) had cultivable A.a. Six of the 15 A.a. culture-positive patients and one of the 29 reference subjects exhibited very high antibody titers against A.a. in saliva. Specific IgG and IgA antibodies in saliva correlated highly significantly with the corresponding antibody values in serum among the patients in the test group. It was concluded that among patients with severe adult periodontitis, the less invasive saliva sample has a diagnostic value equal to that of the serum sample concerning specific antibodies against A.a.

The effect of clindamycin gel insert in periodontal pockets, as observed on smears and cultures

This study is aimed at the evaluation of a 1% clindamycin hydrochloride containing gel on the microbial flora of periodontal pockets deeper than 5 mm. In order to achieve that purpose, 20 patients with pocketing in the premolar-molar regions were selected. Active and placebo gel were inserted once during the first 2 weeks of this experimental study. Microbial samplings were performed 1, 2, 4 and 12 weeks after the experiment started. The samples were submitted to microscopic examination and also to culture. Changes in the microbial content of the periodontal pockets treated by subgingival scaling and clindamycin 1% gel were significant, compared with those obtained with subgingival scaling and placebo gel, particularly with respect to anaerobic black-pigmented bacteria and the motile gram-negative flora. However, after 3 months, most of the treated cases were recolonized by the same initial species, though never at pre-clindamycin levels. In the light of this study, it will be concluded that the use of a small amount of clindamycin hydrochloride inserted into a periodontal pocket, once a week for 2 weeks as a complement to periodontal subgingival scaling, is beneficial in the treatment of adult periodontitis, by eliminating more effectively the microbial pocket colonization.

Purification and partial characterization of an elastolytic serine protease of Prevotella intermedia

Elastolytic strains of Prevotella intermedia were isolated from pus samples of adult periodontal lesions. Elastase was found to associate with envelope, and it could be solubilized with guanidine-HCl. The enzyme was purified to homogeneity by sequential procedures including ion-exchange chromatography, gel filtration, and hydrophobic interaction chromatography. This elastase was a serine protease, and its mass was 31 kDa. It hydrolyzed elastin powder, but collagen and azodye-conjugated proteins were not degraded by this enzyme. Both synthetic substrates for human pancreatic (glutaryl-L-alanyl-L-alanyl-L-prolyl-L-leucine p-nitroanilide) and leukocyte elastase (methoxy succinyl-L-alanyl-alanyl-L-prolyl-L-valine p-nitroanilide) were hydrolyzed.

Changes of subgingival microflora around single-crystal sapphire endosseous implants after experimental ligature-induced plaque accumulation in monkeys

A study was performed to evaluate the change of subgingival microflora with plaque accumulation around the single-crystal sapphire implant. Four implants were inserted into mandibular and maxillary edentulous regions, and the super-structure was inserted 1 month after implant insertion in each of nine monkeys. Plaque control was maintained for 3 months after insertion to establish the baseline. Plaque was allowed to accumulate on one side by placement of ligatures around the implants and natural teeth with no plaque control. On the other side plaque control was continued for 9 months. Both the implants and natural teeth on the ligature side showed significant increases in proportions of motile rods and spirochetes. No significant difference of microflora was detected between the implants and natural teeth. These findings indicate that plaque control is necessary to maintain the normal microflora around the implant.

Purification and characterization of a protease from Porphyromonas gingivalis capable of degrading salt-solubilized collagen

An enzyme capable of hydrolyzing the substrate 4-phenylazobenzyloxycarbonyl-L-prolyl-leucyl-glycyl-prolyl-D-ar gin ine (pZ-peptide), pZ-peptidase, was purified from the oral bacterium Porphyromonas gingivalis. pZ-peptidase hydrolyzed salt-solubilized type I collagen from rat skin, rat plasma low-molecular-weight kininogen, and transferrin at room temperature in the presence of calcium and dithiothreitol. pZ-peptidase did not cleave acid-soluble type I calf skin collagen, type V placental collagen, lysozyme, albumin, or human plasma fibrinogen. Furthermore, the purified enzyme did not hydrolyze N-alpha-benzoyl-DL-Arg-p-nitroanilide, Gly-Pro-p-nitroanilide, N-p-tosyl-Gly-Pro-Arg-p-nitroanilide, N-p-tosyl-Gly-Pro-Lys-p-nitroanilide, azoalbumin, or azocasein. Under reducing conditions, the native enzyme migrated as a single band at 120 kDa on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. However, when heated to 100 degrees C for 10 min in SDS under reducing conditions, the enzyme migrated as a major band at 50 kDa and a minor band at 60 kDa on SDS-polyacrylamide gel electrophoresis. Zymography using calf skin gelatin revealed the gelatin-cleaving activity of the enzyme as evidenced by a diffuse band in the range of 120 to 300 kDa under reducing conditions at room temperature, suggesting that this is the native form of the enzyme. However, incubation at 50 degrees C for 10 min under reducing conditions showed gelatin-cleaving activity at a distinct band of 60 kDa. A minimum temperature of 50 degrees C was required to dissociate the 60-kDa chain from the native complex in active form on gelatin zymography. The ability of the enzyme to cleave other proteins, including kininogen and transferrin, suggests that it has specificity for the Pro-X-Gly sequence found in several proteins, including collagen.

Retention of antimicrobial activity by human root surfaces after in situ subgingival irrigation with tetracycline HCl or chlorhexidine

Substantivity of tetracycline HCl and chlorhexidine digluconate was assessed in extracted teeth. Fifty periodontally compromised teeth scheduled for extraction with probing depths ranging between 6 and 12 mm were root planed and then irrigated in situ with 1 of 4 solutions: tetracycline HCl at concentrations of 10 or 50 mg/ml, 0.12% chlorhexidine digluconate, or 0.9% sterile saline. Each tooth was exposed to 150 ml of the respective irrigation solution. Following extractions, the teeth were transferred to tris buffered saline and incubated at room temperature for 22 days. Incubation solutions were replaced at 24-hour intervals. Removed solutions were examined for desorbed antimicrobial activity using a microtiter assay in which bacterial growth was evaluated by optical density readings. Tetracycline HCl 50 mg/ml exhibited significantly greater antimicrobial activity than chlorhexidine digluconate for 12 days and greater than saline for 16 days. Tetracycline HCl 10 mg/ml exhibited significantly greater antimicrobial activity than chlorhexidine digluconate and saline for 4 days. Chlorhexidine digluconate did not exhibit any significant antimicrobial activity at any time point. Our findings demonstrate long-lasting substantivity of tetracycline HCl, but not chlorhexidine digluconate, by teeth exposed to a single episode of pocket irrigation of their periodontally-exposed roots. The amount of antimicrobial activity retained is proportional to the concentration of tetracycline HCl used for irrigation.

Comparison of the distribution of Actinomyces in dental plaque on inserted enamel and natural tooth surfaces in periodontal health and disease

The distribution of Actinomyces naeslundii, Actinomyces viscosus and Actinomyces odontolyticus in healthy and diseased adult populations was studied in 3 different ways. First, supragingival plaque formation at 2 through 72 h was examined in 12 periodontally healthy adults using a removable pre-measured surface of enamel bonded to molars and premolars. Second, a cross-sectional examination of the composition of both supragingival and subgingival plaque of unknown age was conducted in 205 adults exhibiting periodontal health to moderate disease. Third, the effects of oral hygiene instruction and root planing on the subgingival microflora of a subset of 19 subjects with moderate periodontitis were examined. The evaluation of 12 adults revealed that the predominant species in early plaque formation (2, 4 and 8 h) was A. odontolyticus. A. viscosus and A. naeslundii were present in developing plaques in almost all subjects in 2-h plaque, but absent in half the subjects when 4-, 8- or 24-h plaque was examined. These two species significantly increased in numbers per mm2 enamel surface area in 48- and 72-h plaques. A. odontolyticus was not related to clinical signs of periodontal disease in 205 adults, and its subgingival proportions in plaque did not change following periodontal treatment of 19 individuals. A. naeslundii was found in significantly higher numbers in supragingival than subgingival plaques in the 205 adults examined. The mean proportion of A. naeslundii significantly decreased as the magnitude of probing depth and attachment loss increased. The proportions of A. naeslundii and A. viscosus were found to be significantly increased in subgingival plaques following periodontal treatment.

Monoclonal antibodies to lipopolysaccharide of four oral bacteria associated with periodontal disease

Periodontal disease is a common inflammatory disease which erodes the supporting structures of the teeth, and is initiated by a subgingival infection with selected Gram-negative bacteria. Monoclonal antibodies (mAb) to lipopolysaccharide (LPS) of four periodontal pathogens, A. actinomycetemcomitans, P. intermedia, F. nucleatum and P. gingivalis were examined for specificity and their ability to bind these pathogens in a particle concentration fluorescence immunoassay (PCFIA). The mAb selected were specific for their homologous bacteria and when tested against a large battery of other bacteria, including 16 genera and 46 species, were found not to cross-react with heterologous species. When each of the mAb was challenged with 40 or more homologous freshly isolated bacteria, more than 90% were positive. Non-cellular antigens in the form of soluble LPS and extracellular vesicles were examined for their ability to bind to assay components and alter the apparent results of the assay. LPS was found to have potential as an interfering agent if bound to assay components prior to sample treatment, but this non-specific binding was significantly reduced when a surfactant was added to the buffers. Extracellular vesicles had no significant effect on the estimation of P. gingivalis by the assay.

Phosphorylated nutrient uptake by Treponema denticola and other potential periodontopathogens

Nutrient uptake may contribute to the survival of certain potential periodontopathogens in the competitive environment of the gingival sulcus. This study was conducted to assess the uptake of commercially available, key radiolabelled phosphorylated compounds by Treponema denticola. There was a linear relationship in the uptake of ATP and G-1-P with cell concentrations of 0.1-2.5 mg of cell dry weight. This uptake reached a steady state within 15 min, and at temperatures of 25-37 degrees C the uptake ranged between 13-21%. At 50 degrees C, or above 50 degrees C the assay cells took up 0-1% of the assay nutrients. The maximum uptake of ATP was 47.5, 38 and 47.6 pmoles for serovars a, b and c. G-1-P yielded maximum uptake values of 306, 304, and 306 pmoles respectively. Significant uptake of ATP, or G-1-P occurred at pH 4.8 for serovars a, or c, while serovar b showed a broad pH range for the uptake of G-1-P. Stannous fluoride at a concentration of 0.17 mM enhanced the uptake of ATP while chlorhexidine digluconate inhibited the uptake of ATP. At concentrations usually employed (0.05-0.5 mM) the metabolic poisons 2,4-dinitrophenol, sodium azide, sodium arsenite and the ATPase inhibitor N,N1-dicyclohexylcarbodiimide did not alter significantly the uptake of ATP. The uptake of ATP, by Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Fusobacterium nucleatum and T. denticola at pH 4.8 was 13.4, 1.5, 6.9, and 18-20.4%, respectively. At pH 6.5 the uptake for the microorganisms indicated above was 22, 1.3, 6.6 and 6.2%, respectively. G-1-P showed the same trend in its uptake by A. actinomycetemcomitans, P. gingivalis, F. nucleatum and T. denticola. This study provides for the first time specific examples of phosphorylated nutrient uptake by potential periodontopathogens, and that the uptake of phosphorylated nutrients can be suppressed by oral hygienic compounds.

Correlation between cell-adherent activity and surface structure in Porphyromonas gingivalis

The cell-adherent ability of 6 strains of Porphyromonas gingivalis (381, ATCC 33277, SU63, KD1, W50 and W83) was compared by using radiolabeled bacterial cells and human gingival fibroblasts (Gin 1), human periodontal ligament fibroblasts (HPLF) and human epithelial cells (Ca9-22) that had been grown on collagen beads. The cell-adherent activity of these organisms varied among strains; P. gingivalis strains 381, ATCC 33277 and SU63 bound to the target cells at a range of 14% to 72%, but the other 3 strains (KD1, W50 and W83) were scarcely bound (0.6% to 3.5%). On the other hand, whole bacterial cells and culture supernatants of all strains showed distinct hemagglutinating activity. The 3 strains showing high cell-adherent activity were hydrophobic and the other strains showing less activity were relatively hydrophilic. Furthermore, a number of peritrichous fimbriae were found on the surface of P. gingivalis strains 381, ATCC 33277 and SU63, which showed high adherent activity, whereas, fimbriae on the other 3 strains showing low adherent ability were barely apparent. Therefore, it was assumed that the cell-adherent activity of P. gingivalis was related to the hydrophobicity of the cell surface, which was related to the number of fimbriae.

Rapid identification of Actinobacillus actinomycetemcomitans based on analysis of 23S ribosomal RNA

Actinobacillus actinomycetemcomitans is a key microorganism in the pathogenesis of several different forms of periodontal diseases. Identification of this bacterium from clinical specimens may often be complicated by the fact that the colony morphology on TSBV selective medium closely resembles that of Haemophilus aphrophilus and a key differentiating characteristic, catalase reaction, may be variable. Recent genetic studies have shown that the 23S ribosomal RNA molecule is split into two smaller forms in A. actinomycetemcomitans, but is intact in H. aphrophilus. Based on this finding, we describe a new, rapid method for identifying A. actinomycetemcomitans in which single colonies isolated from culture on TSBV agar in 5% CO2 in air are lysed, electrophoresed on 1.5% submarine agarose gels and visualized by staining with ethidium bromide. Using this assay, A. actinomycetemcomitans can be easily distinguished from morphologically similar colonies such as H. aphrophilus strains by differences in 23S rRNA within 2 h.

Cloning of the gene encoding a glycylprolyl aminopeptidase from Porphyromonas gingivalis

A genomic library of Porphyromonas gingivalis 381 was constructed in the cosmid vector pHC79. A clone, pSN1, was identified by the expression of glycylprolyl-naphthylamide hydrolysing activity. The DNA insert contained within the cosmid pSN1 was subcloned into the plasmid vector pBR328 to create the recombinant plasmid pSN11 containing a 2.9 kb EcoRV insert. An Escherichia coli transformant containing pSN11 produced a protein having a molecular weight of 75 kDa. Southern-blot hybridization revealed that the 2.9 kb EcoRV DNA hybridized with an identical sized Eco RV DNA fragment in the chromosomal DNA of P. gingivalis 381.

A preliminary evaluation of the use of a redox agent in the treatment of chronic periodontitis

A small-scale clinical trial was carried out to evaluate the effect of a redox agent, methylene blue, on microbiological and clinical indices of chronic periodontitis. Methylene blue was applied subgingivally on a daily basis for 7 d to 25 test sites in 7 patients and the sites evaluated clinically and microbiologically for up to 14 d: 25 control sites in the same patients received sterile water. The test sites showed statistically significant differences from the control sites in terms of changes in a number of clinical and microbiological indices. In the test sites the proportions of anaerobes, Gram-negative anaerobes, spirochetes and motile bacteria decreased, as did the crevicular fluid flow, while the proportions of facultative anaerobes and cocci increased. These changes are indicative of a shift towards periodontal health. No significant differences were observed between the test and control sites in terms of bleeding on probing or pocket depth. The encouraging results of this preliminary study suggest that the use of redox agents in the treatment of chronic periodontitis warrants further investigation.

Anti-proliferative and cytotoxic activity of surface-associated material from periodontopathogenic bacteria

The easily solubilized surface-associated material from three bacterial species associated with periodontal diseases, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Eikenella corrodens, produced dose-dependent inhibition of thymidine incorporation by human fibroblasts, the human monocytic cell line U937 and guinea pig epidermal cells. In contrast, lipopolysaccharides from A. actinomycetemcomitans and P. gingivalis were either inactive or substantially less active over the dose range tested. One of the constituents of surface-associated material from a 'non-leucotoxic' strain of A. actinomycetemcomitans was highly cytotoxic to human peripheral blood polymorphonuclear cells, with 50% killing from less than 1 ng/ml. A constituent of the surface-associated material from P. gingivalis was approximately one log order less active. The lipopolysaccharides from these bacteria were at least three log orders less active in neutrophil killing. These findings add weight to the hypothesis that easily solubilized exopolymers from periodontopathogens play a major part in the pathology of periodontal diseases.

Cloning, expression, and sequencing of a protease gene (tpr) from Porphyromonas gingivalis W83 in Escherichia coli

Porphyromonas gingivalis is a highly proteolytic organism which metabolizes small peptides and amino acids. Indirect evidence suggests that the proteases produced by this microorganism constitute an important virulence factor. In this study, a gene bank of P. gingivalis W83 DNA was constructed by cloning 0.5- to 20-kb HindIII-cut DNA fragments into Escherichia coli DH5 alpha by using the plasmid vector pUC19. A clone expressing a protease from P. gingivalis was isolated on LB agar containing 1% skim milk. The clone contained a 3.0-kb insert that coded for a protease with an apparent molecular mass of 64 kDa. Sequencing part of the 3.0-kb DNA fragment revealed an open reading frame encoding a protein of 482 amino acids with a molecular mass of 62.5 kDa. Putative promoter and termination elements flanking the open reading frame were identified. The activity expressed in E. coli was extensively characterized by using various substrates and protease inhibitors, and the results suggest that it is possibly a thiol protease.

Suppressive effect of soluble factor(s) derived from Prevotella loescheii ATCC 15930 on proliferation of human lymphocytes

Soluble sonic extracts of Prevotella loescheii caused a dose-dependent inhibition of human peripheral blood lymphocyte proliferation by mitogen and of the proliferation of a leukemic cell line, BALL-1, when assessed by DNA synthesis (3H-thymidine incorporation). RNA (3H-uridine incorporation) and protein (3H-leucine incorporation) synthesis were similarly altered after exposure to the extract. There was no effect on cell viability as measured by either trypan blue exclusion or extracellular release of the cytoplasmic enzyme lactate dehydrogenase. Preliminary characterization indicates the suppressive factor(s) derived from P. loescheii to be a protein since it is heat-labile and trypsin-sensitive. The factor eluted in a peak on a high-pressure liquid chromatography gel filtration corresponding to a molecular weight of approximately 32,000. Since black-pigmented anaerobic rods have been implicated in the pathogenesis of periodontal disease, the data suggest that P. loescheii contributes to the disease process by suppressing lymphocyte function.

Issues in the evaluation of clinical trials of periodontitis: a clinical perspective

The goals of clinical trials designed to establish claims for equivalency or superiority of treatment for periodontitis must be clearly stated and defined in terms of measurable and meaningful response variables. It is suggested that these clinical trials use designs that compare new treatment methods to basic periodontal therapy which consists of thorough scaling and root planing, oral hygiene instruction, and regular maintenance care. The primary response variable should be clinical attachment level. It is important to document changes in probing depth since this is a meaningful measure to many clinicians. Gingival inflammation and bleeding should be used as secondary response variables because these are not necessarily indicative of progressive periodontal destruction. Radiographic measures of disease may be useful as primary response variables if safe, reproducible and valid methods of measuring change are utilized. Microbiological monitoring should be a secondary response variable because of numerous questions concerning sampling methodology, quantitative expression of data, and meaningful interpretation in terms of relevance to disease activity. The length of periodontitis trials should be set at a minimum of 9 months if claims of superiority or equivalency are made compared to basic periodontal therapy. Calibration trials should be included and measurement error should be expressed in terms that are meaningful to the clinician while retaining statistical validity. Statistical methods for determining change should take into account site and subject heterogeneity, bursts of change and gradual change over time. It is important that statistical techniques be used that detect change as early as possible and that appropriate consideration be given to the clinical implications of the type, magnitude and duration of change in outcome variables.

Early effects of periodontal therapy on the detection frequency of four putative periodontal pathogens in adults

This study aimed to examine early posttreatment changes in the periodontal microflora. Paper point sampling and conventional bacterial cultivation were used to monitor the effects of surgical and non-surgical periodontal therapy on the detection frequency of Porphyromonas gingivalis, Prevotella intermedia, Actinobacillus actinomycetemcomitans, and Capnocytophaga species in deep periodontal pockets. Ten patients, 5 men and 5 women (mean age 44 years), with advanced periodontal disease were selected from the dental school patient population for the study. A total of 245 teeth in 10 defined areas of the dentition were treated by oral hygiene instruction followed by scaling and root planing alone (121 sites) or with surgical interventions (124 sites). Ninety sites, 47 surgical and 43 non-surgical, with initial pocket depth greater than or equal to 6 mm were sampled at baseline and 3 months after completion of therapy. Treatment by both procedures resulted in significant clinical improvements as assessed by all clinical parameters used. Baseline results may indicate that the level of P. gingivalis was reduced in the presence of P. intermedia, while A. actinomycetemcomitans seemed to be reduced in the presence of P. gingivalis and/or P. intermedia. Three months after therapy, the detection frequency of P. gingivalis was significantly reduced (P less than 0.05) in surgical and non-surgical sites while the reduction for P. intermedia was significant only for surgical sites (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Gene cloning of Porphyromonas gingivalis specific antigens recognized by serum of adult periodontitis patient

1. Porphyromonas gingivalis is believed an important pathogen of adult periodontitis. A gene library of P. gingivalis 381 was constructed in lambda phage vector L47.1. The library was probed with serum obtained from patients of severe adult periodontitis. Two clones, lambda MDBG101 and lambda MDBG103 which were expressed, 200 and 160 kDa respectively, were selected and further studied. 2. The expressed antigens in these two clones were also reacted with rabbit antiserum against whole cells, capsular fraction and cell surface fraction of P. gingivalis. 3. Genes coding protein antigens in lambda MDBG101 and lambda MDBG103 were subcloned into high-copy-number plasmid vector pACYC184 and subclones obtained were designated as MD101 and MD103. Recombinant plasmids, pMD101 and pMD103, differed in their restriction endonuclease digestion. 4. Immunodiffusion analysis showed that cloned proteins from MD101 and MD103 reacted with antiserum against P. gingivalis but did not react with antiserum against Prevotella intermedia, Prevotella loescheii and Prevotella asaccharolyticus. 5. These data suggest that P. gingivalis species-specific antigens has been successfully cloned and expressed in Escherichia coli. Since these cloned specific antigens were recognized by adult periodontitis patient sera, the recombinant antigen will be useful material for the development of serodiagnosis of P. gingivalis infection in adults periodontitis.

Periodontal bone loss in mice induced by different periodontopathic organisms

Periodontal bone loss in mice orally inoculated with Peptostreptococcus anaerobius, Pept. magnus and Actinobacillus actinomycetemcomitans was compared to that in sham-inoculated mice. Six-to-8-week-old BALB/c mice were inoculated with 1 x 10(5), 1 x 10(7) or 1 x 10(9) colony-forming units (c.f.u.) of bacteria in 50 microliters of medium. Ten mice received each concentration of bacteria and 10 sham-inoculated mice acted as controls. Five mice from each of the groups were killed 6 weeks after inoculation and the remaining five mice at 12 weeks. Right hemimandibles were defleshed, stained and bone loss was measured using an image analyser. All the organisms tested were associated with bone loss. Animals that had received Pept. anaerobius and Pept. magnus had up to 18% more bone loss than those sham inoculated. In contrast, mice inoculated with A. actinomycetemcomitans had up to 38% more bone loss than the sham-inoculated animals, this amount of loss occurring at the lowest inoculation of 1 x 10(5) c.f.u. These data demonstrate a differential ability of micro-organisms to cause periodontal bone loss in mice.

Clinical effect of subgingival chlorhexidine irrigation on gingivitis in adolescent orthodontic patients

Twenty-three adolescent orthodontic patients with gingivitis affecting all banded first molars volunteered for the study. Three measures associated with gingivitis (papilla bleeding index, plaque index, and probing depth) were recorded at four sites for all four molars. A single application of subgingival irrigation with 0.12% chlorhexidine digluconate or isotonic saline was performed for 5 seconds at each site. As determined by coin toss, the first molars on the right or left side of the mouth received either chlorhexidine or saline irrigation. The papilla bleeding index, plaque index, and probing depth were recorded before the treatment and subsequently at 2 weeks and then 4 weeks. The gingival bleeding as determined by papilla bleeding index, was virtually eliminated in 4 weeks by a single application of subgingival irrigation with either chlorhexidine or saline. However, there was no significant reduction in pocket depth or plaque index. In addition, no significant difference between the effect of chlorhexidine or saline was found for any of the outcome measures.

Microbiology of healthy and diseased periodontal sites in poorly controlled insulin dependent diabetics

A group of poorly-controlled insulin dependent diabetes mellitus (IDDM) patients were examined in a cross-sectional design for total microbial levels, microbial incidence, and the percent levels of selected periodontal microorganisms. These organisms were selected on the basis of prior reports that associated them with either periodontal disease or health. One periodontally-healthy and one periodontally-diseased site were examined in each IDDM patient. Increased levels of the periodontal pathogens Prevotella intermedia, P. melaninogenica spp., Bacteroides gracilis, Eikenella corrodens, Fusobacterium nucleatum and Campylobacter rectus (formerly Wolinella recta) were found at the periodontal diseased sites. Increased prevalence of the organisms P. intermedia, P. melaninogenica spp., and C. rectus were found at the diseased sites. A significantly higher percentage of P. intermedia was found at the sites exhibiting deep pockets and attachment loss.

A sensitive enzymatic method (SK-013) for detection of Treponema denticola, Porphyromonas gingivals and Bacteroides forsythus in subgingival plaque samples

An enzymatic method, SK-013, was developed for rapid detection of the peptidase activity in subgingival plaque samples. This method was found to have specificity for Porphyromonas gingivalis, Treponema denticola, Bacteroides forsythus, and some Capnocytophaga strains. The purpose of this study was to determine whether SK-013 could indicate the presence of periodontopathic bacteria, including T. denticola, P. gingivalis and B. forsythus, which produce trypsin-like enzymes. Subgingival plaque samples were taken from 10 clinically healthy sites and 30 periodontally diseased sites with 3 paper points. SK-013 activity of plaque samples was assayed, and the numbers of T. denticola, P. gingivalis and B. forsythus in the sample were counted by immunofluorescence technique. In diseased sites, the SK-013 activity was significantly correlated with clinical parameters such as Gingival Index, Plaque Index, probing depth and bleeding on probing. A significant correlation was found between the presence of these organisms and SK-013 activity. Correlation coefficients between the presence of T. denticola and SK-013 activity were higher than those with other organisms. These findings indicate that the SK-013 is useful as an indicator of cell population of T. denticola, P. gingivalis and B. forsythus in subgingival plaque.

Disseminated actinomycosis due to Actinomyces meyeri and Actinobacillus actinomycetemcomitans

A 44-year-old man presented with pulmonary lesions and neurological symptoms suggestive of lung carcinoma with cerebral metastases. He had non-specific chest X-ray findings since 6 years and he also suffered from relapsing purulent skin lesions which resolved spontaneously or by short courses of antibiotic treatment. When corticosteroids were given, multiple subcutaneous swellings developed that spontaneously ruptured. The pus contained Actinomyces meyeri and Actinobacillus actinomycetemcomitans. On operation, the intracerebral lesions appeared to be abscesses and the same bacteria were cultured as from the skin lesions. Bronchoscopical examination did not reveal a diagnosis. Amoxicillin was given for 12 months and the patient recovered.

Salivary IgA responses to Porphyromonas gingivalis in the cynomolgus monkey. 1. Total IgA and IgA antibody levels to P. gingivalis

Porphyromonas gingivalis has been associated with the subgingival plaque of advancing disease lesions in various types of periodontitis. Additionally, this species of oral microorganism has been found to increase dramatically in ligature-induced periodontitis in nonhuman primates (Macaca fascicularis) and has recently been shown to induce progressing disease when implanted into the subgingival plaque in this animal model. Although systemic antibody responses have been demonstrated to P. gingivalis in both human and nonhuman primate with periodontitis, no information is available on the oral secretory IgA antibody response to this bacteria. This report describes the methods for reproducible collection of salivary secretions from cynomolgus monkeys and the development of methods for analyzing salivary IgA levels and specific IgA antibody in the saliva reactive with P. gingivalis. Purification of monkey salivary IgA allowed quantification of IgA using an enzyme-linked immunosorbent assay (ELISA). Estimation of total IgA levels in saliva showed approximately a 20% greater level of IgA in whole versus parotid saliva from a group of 13 monkeys, with a 2-3 fold variation in levels among this group of animals. Naturally occurring salivary IgA antibody to P. gingivalis, as measured by ELISA, were routinely detectable but low in whole saliva; however, many of the parotid saliva specimens collected exhibited negligible levels of antibody to this microorganism. The IgA antibody in whole saliva showed nearly an 18-fold variation among the samples from the monkeys. Correlational analyses indicated that, although there was a positive relationship between antibody levels in whole and parotid saliva, the majority of natural IgA antibody in whole saliva appears to be derived from other sources.(ABSTRACT TRUNCATED AT 250 WORDS)

Restorative margin placement and periodontal health

Subgingival restorative margins are associated with the development of plaque-related inflammatory periodontal disease, primarily because of a shift in the subgingival microflora from a profile associated with health to one associated with disease. The degree and extent of the marginal inflammation is influenced by four factors: failure to maintain proper emergence profile, inability to adequately finish and/or close subgingival margins, placement of subgingival margins in an area with minimum to no attached gingiva, and violation of the biologic width. Supragingival margin placement is the location of choice for all restorative margins to avoid iatrogenic periodontal disease. However, consideration of these four factors will help reduce the adverse impact of restorative margins that must be carried subgingivally.

The microflora of periodontal sites showing active destructive progression

20 adult periodontitis (AP) subjects were examined every 2 to 4 months and microbiological samples were collected and cultured when 2 mm or more loss of attachment (active sites) was detected by 2 examiners. Similar sites in which no progressive destruction was observed (control sites) also were sampled in the same subjects. By lambda-analysis, there was no statistically significant difference in floras of active (42 sites from 12 subjects) and control (36 sites from 12 subjects) sites or between the floras of the active and control sites and of 63 samples from 22 AP subjects that were examined previously in a cross-sectional study. By paired t test, no microbial species had a significantly greater association with active than with control sites. The only species that were detected in one or more samples from all subjects with active sites were Wolinella recta, Fusobacterium nucleatum, and Peptostreptococcus micros. Porphyromonas gingivalis and 9 other taxa were isolated from one-half or more of the persons with active sites. The composition of microbiological floras of all periodontitis samples was statistically significantly different from that of subjects with healthy gingiva. The composition of microfloras of sites in subjects with naturally-occurring gingivitis was intermediate between that of subjects with healthy gingiva and that of active and control sites in AP subjects.

Systemic antibody responses to oral microorganisms in the cynomolgus monkey: development of methodology and longitudinal responses during ligature-induced disease

Systemic antibody responses to oral microorganisms were studied during ligature-induced periodontal disease in a non-human primate (Nhp) model. Methodology was developed using ELISA techniques to assess total IgG and IgM levels in the serum from the Nhp. In addition, an ELISA was developed utilizing affinity-purified anti-human isotype reagents to detect Nhp serum antibody responses to Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Prevotella intermedia and Fusobacterium nucleatum. Results showed that the anti-human reagents detected IgG and IgM from Macaca fascicularis with an efficiency of 25-35% and 50-60%, respectively. Following ligation, groups of Nhp were treated with an immunomodulator ("Thymopentin", TP5) or placebo to examine the effect of the T-cell stimulating agent on periodontitis and host responses. No differences were noted in total serum IgG and IgM levels for individual Nhp or between groups when baseline, ligation and treatment intervals were compared. However, following ligation, 8/12 Nhp exhibited significant increases in IgG and/or IgM antibody to P. gingivalis that were coincident with increases in the percentage of this microorganism in the subgingival plaque from the ligated sites. During the treatment phase, the antibody levels in the placebo group continued to increase, while the levels in the TP5-treated group stabilized. The findings in this study indicate that the emergence of a microorganism in the subgingival plaque (P. gingivalis) during the conversion from gingivitis to progressing periodontitis in the Nhp, elicits a systemic antibody response that is specific for the microorganism.

Adhesive properties of strains of Fusobacterium nucleatum of the subspecies nucleatum, vincentii and polymorphum

This study surveyed some adhesive properties of strains of Fusobacterium nucleatum representative of the 3 recently defined groups or subspecies that could relate to their colonization and virulence. With one exception, F. nucleatum strains agglutinated sheep erythrocytes, but the quantity of bacteria required and the sensitivity of the hemagglutination reactions to inhibition by 0.05 M galactose or arginine varied between strains, and did not exhibit clear-cut correlations with subspecies. Neuraminidase treatment of erythrocytes generally enhanced the hemagglutinating activity of most strains, but trypsin treatment had no effect. Strains of F. nucleatum also attached in moderate numbers to buccal epithelial cells. Treatment of the epithelial cells with neuraminidase or with trypsin increased the numbers of all Fusobacterium strains that attached. Treatment of hydroxyapatite (HA) beads with submandibular or parotid saliva also promoted the adhesion of all strains of F. nucleatum studied. Treatment of HA with human serum or albumin produced a selective effect. Adhesion of some strains was promoted by serum and albumin treatment, and that of other strains was unaffected. Adhesion of all strains of F. nucleatum was enhanced to statherin-treated HA, whereas HA treated with salivary proline-rich protein-1 did not foster F. nucleatum attachment. Three of 4 strains of the subspecies vincentii, and each of 2 polymorphum strains studied exhibited strong adhesion to HA treated with either human type I or type IV collagen. However, only 1 of 5 strains of the subspecies nucleatum bound well to collagen-treated HA.(ABSTRACT TRUNCATED AT 250 WORDS)

Subgingival microflora of advanced periodontitis in the Dominican Republic

A study of the predominant subgingival microflora was carried out in 24 periodontitis patients, 18 to 60 years of age, in Santo Domingo, Dominican Republic. Paper point sampling, transport in VMGA III, and conventional microbiological techniques were utilized. Direct microscopic examination revealed that cocci and nonmotile organisms made up 85% of the total organisms and spirochetes as little as 3%. Nonselective culturing showed Gram-negative organisms to constitute 53% of total isolates. Fusobacterium nucleatum averaged 15%, black-pigmented anaerobes 7%, and Peptostreptococcus micros 10% of the cultivable microflora. Enteric rods and acinetobacter species were recovered from 16 patients and comprised 23% of the cultivable flora. Enterobacter cloacae occurred in 8 patients, Klebsiella oxytoca in 3 patients, and 7 other species in 10 patients. Parallel studies have found a significantly lower prevalence of enteric rods in advanced periodontitis patients in the USA. In conclusion, fewer spirochetes and markedly more enteric rods seem to inhabit adult periodontitis lesions in Santo Domingo patients compared to those in USA. High levels of subgingival enteric rods in periodontitis patients in Santo Domingo may have important prophylactic and therapeutic implications.

Humoral immune response to an antigen from Porphyromonas gingivalis 381 in periodontal disease

The humoral immune responses of patients with periodontitis were evaluated to characterize the host response to Porphyromonas gingivalis. A sonic extract of P. gingivalis 381 from whole cells was fractionated by gel chromatography and ion-exchange chromatography. The fractionated extracts were evaluated by Western blot (immunoblot) analyses with patient sera. A dominant antigen was identified from the sonic extract with an apparent molecular mass of 53 kDa. The 53-kDa protein antigen (Ag53) was purified by affinity chromatography by using a monoclonal antibody. Ag53 was detected on the vesicle surface of P. gingivalis 381 by immunoelectron microscopy by using the monoclonal antibody and was detected as a major protein in the outer membrane and in vesicles by Western blot analysis. Monoclonal antibody cross-reactivity to Ag53 in the sonic extracts of P. gingivalis ATCC 33277, P. gingivalis 1021, and Porphyromonas endodontalis ATCC 35406 was revealed. Seventy-seven patients with periodontitis were examined for their responses to Ag53. Serum immunoglobulin G (IgG) from 54 patients reacted strongly to Ag53; however, serum IgG from the remaining 23 patients did not exhibit detectable reactivity at all to Ag53, even though the patients had high serum IgG titers to the sonic extract. Ag53 is a new marker that represents an interesting aspect of the humoral immune response to P. gingivalis in patients with periodontitis.