Subgingival microflora and periodontal conditions in healthy teenagers

Periodontal diseases in Thai schoolchildren. Clinical and microbiological observations

The prevalence of periodontitis among Thai schoolchildren is unknown. In a cross-sectional study, the prevalence and severity of periodontal diseases, in a group of Thai schoolchildren, along with the presence and numbers of bacterial species commonly associated with periodontitis were investigated. A consent form was sent out to 192 schoolchildren in one school (Chanachanupathom School) in Chana, Southern Thailand (in the age range of 12-18 years) and 119 attended for a clinical and microbiological examination. Clinical recordings included number of teeth present, DMFT, plaque index, bleeding index, clinical attachment loss (CAL), and probing pocket depth (PPD). Pooled plaque samples were analyzed with culture and qPCR against bacteria associated with periodontitis. The children had low caries experience (DMFT = 3.2 ± 2.3), poor oral hygiene, high bleeding scores, and 67 (56.3%) had at least one interproximal site with CAL ≥ 1 mm. Thirty-seven (31.1%) of the children were diagnosed with periodontitis stage I, and sixteen (13.4%) were classified as periodontitis Stage II. Aggregatibacter actinomycetemcomitans was sparsely found in all but the healthy clinical groups (gingivitis, periodontitis Stage I and II), while the groups showed a high prevalence of Fusobacterium spp., Prevotella intermedia/nigrescens, and Campylobacter species as well as of the periodontitis-associated species Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. Thai schoolchildren have poor oral hygiene with abundant amounts of plaque and high presence of bleeding. Early onset periodontitis is common but mostly in its mild form and is not associated with the presence of A. actinomycetemcomitans.

Microbiology of aggressive periodontitis

For decades, Aggregatibacter actinomycetemcomitans has been considered the most likely etiologic agent in aggressive periodontitis. Implementation of DNA-based microbiologic methodologies has considerably improved our understanding of the composition of subgingival biofilms, and advanced open-ended molecular techniques even allow for genome mapping of the whole bacterial spectrum in a sample and characterization of both the cultivable and not-yet-cultivable microbiota associated with periodontal health and disease. Currently, A. actinomycetemcomitans is regarded as a minor component of the resident oral microbiota and as an opportunistic pathogen in some individuals. Its specific JP2 clone, however, shows properties of a true exogenous pathogen and has an important role in the development of aggressive periodontitis in certain populations. Still, limited data exist on the impact of other microbes specifically in aggressive periodontitis. Despite a wide heterogeneity of bacteria, especially in subgingival samples collected from patients, bacteria of the red complex in particular, and those of the orange complex, are considered as potential pathogens in generalized aggressive periodontitis. These types of bacterial findings closely resemble those found for chronic periodontitis, representing a mixed polymicrobial infection without a clear association with any specific microorganism. In aggressive periodontitis, the role of novel and not-yet-cultivable bacteria has not yet been elucidated. There are geographic and ethnic differences in the carriage of periodontitis-associated microorganisms, and they need to be taken into account when comparing study reports on periodontal microbiology in different study populations. In the present review, we provide an overview on the colonization of potential periodontal pathogens in childhood and adolescence, and on specific microorganisms that have been suspected for their role in the initiation and progression of aggressive forms of periodontal disease.

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

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

Minor manifestations of periodontal diseases in young adults with type 1 diabetes mellitus. Periodontal and microbiological findings

OBJECTIVE

The aim of this study was to evaluate periodontal status and microbiological conditions in young adults with insulin-dependent diabetes (IDDM) in comparison with age- and sex-matched non-diabetic controls.

MATERIALS AND METHODS

Forty-one patients, 18-24 years of age with IDDM since childhood, were examined and the results were compared to those of a group of 41 sex- and age-matched non-diabetic controls. According to the HbA(1c) %, the group of diabetic patients was divided into two groups, with good or poor metabolic control.

RESULTS

Periodontal health, expressed in probing pocket depths and marginal bone loss, was fairly good in all patients. Fifty per cent of the patients in the study and control groups displayed probing pocket depths ≥4 mm, mostly pocket depths 4 mm. These findings were also equally distributed among the patients with good and poor metabolic control. No significant differences were found between the groups regarding bleeding on probing, but in the number of sites with excessive bleeding the study group exhibited higher scores than the healthy controls. Different microbiological species were equally distributed between the groups.

CONCLUSION

Neither periodontal nor microbiological status in young adults with IDDM differs from that of healthy controls.

Tracking of plasma antibodies against Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis during 15 years

BACKGROUND

Plasma antibody measurements of antibody levels to periodontal pathogens may be used to support diagnosis, disease activity, classification, and prognosis of periodontitis.

OBJECTIVE

The aim of this study was to investigate the long-term stability of plasma antibody levels against Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis.

DESIGN

Plasma immunoglobulin G (IgG) antibody levels against the pathogens were analyzed annually during 15 years from 21 voluntary subjects, whose periodontal status was not known at the point of selection. The total number of plasma samples was 315. In connection of the last sampling, the clinical and radiographic periodontal status was examined. Pooled bacterial samples from periodontal pockets, as well as salivary samples were collected for A. actinomycetemcomitans and P. gingivalis detection, and antibody determinations, respectively. According to the clinical status, six subjects had periodontitis, whereas 15 did not.

RESULTS

Plasma IgG-class antibody levels to periodontal pathogens remained extremely stable during the 15-year period and no significant (p>0.05) intra-individual variations were observed. Retrospectively, the average plasma IgG antibody levels against A. actinomycetemcomitans and P. gingivalis were 1.6-2.3 (p<0.05) and 1.4-1.7 (p<0.05) fold higher in the subjects with periodontitis than those without, respectively, during the whole 15-year tracking. As expected, at the time of the periodontal examination the plasma and salivary IgG antibody levels were associated both with periodontitis and bacterium-positivity.

CONCLUSIONS

Plasma IgG levels against A. actinomycetemcomitans and P. gingivalis are extremely stable during 15 years both in subjects with and without periodontitis.

Distribution of biotypes and leukotoxic activity of Aggregatibacter actinomycetemcomitans isolated from Brazilian patients with chronic periodontitis

Aggregatibacter actinomycetemcomitans is an important etiologic agent of the periodontitis and is associated with extra-oral infections. In this study, the detection of the ltxA gene as well as the ltx promoter region from leukotoxic A. actinomycetemcomitans isolated from 50 Brazilian patients with periodontitis and 50 healthy subjects was performed. The leukotoxic activity on HL-60 cells was also evaluated. Leukotoxic activity was determined using a trypan blue exclusion method. The 530 bp deletion in the promoter region was evaluated by PCR using a PRO primer pair. A. actinomycetemcomitans was detected by culture and directly from crude subgingival biofilm by PCR using specific primers. By culture, A. actinomycetemcomitans was detected in nine (18%) of the periodontal patients and one (2%) healthy subject. However, by PCR, this organism was detected in 44% of the periodontal patients and in 16% of the healthy subjects. It was verified a great discrepancy between PCR detection of the ltx operon promoter directly from crude subgingival biofilm and from bacterial DNA. Only one periodontal sample harbored highly leukotoxic A. actinomycetemcomitans. Moreover, biotype II was the most prevalent and no correlation between biotypes and leukotoxic activity was observed. The diversity of leukotoxin expression by A. actinomycetemcomitans suggests a role of this toxin in the pathogenesis of periodontal disease and other infectious diseases.

Relationship of Actinobacillus actinomycetemcomitans serotypes to periodontal condition: prevalence and proportions in subgingival plaque

No study available has utilized the new classification scheme (the consensus report of the American Academy of Periodontology 1999) to determine the prevalence of Actinobacillus actinomycetemcomitans in different periodontal conditions. The purpose of this study was to investigate prevalence and proportions of A. actinomycetemcomitans serotypes in subgingival plaque samples from a young Taiwanese population with aggressive periodontitis, chronic periodontitis and no periodontal disease. A total of 221 subgingival plaque samples from 171 diseased subjects (70 had aggressive periodontitis, and 101 had chronic periodontitis) (mean age 25.0 +/- 8.2 yr) and 50 periodontally healthy subjects (mean age 18.4 +/- 9.5 yr) were screened for A. actinomycetemcomitans. Serotypes of A. actinomycetemcomitans were determined by an indirect immunofluorescence assay using serotype-specific polyclonal antisera to A. actinomycetemcomitans strains ATCC 29523 (serotype a), ATCC 43728 (serotype b) and ATCC 33384 (serotype c). Prevalence (% of positive samples) of A. actinomycetemcomitans was 84.3% in aggressive periodontitis, 60.4% in chronic periodontitis, and 64.0% in periodontally healthy subjects. Proportions of A. actinomycetemcomitans (mean percentage per total bacteria) in periodontally healthy subjects were significantly lower than in aggressive periodontitis subjects. The proportion of serotype b in subjects with aggressive periodontitis and subjects with chronic periodontitis were significantly greater than that in periodontally healthy subjects. The proportion of serotype c in periodontally healthy subjects was much higher than that in chronic periodontitis subjects. The results of this study suggest that prevalence and proportions of A. actinomycetemcomitans are significantly greater in patients with aggressive periodontitis than in those with chronic periodontitis. Serotype b is the predominant serotype of A. actinomycetemcomitans in patients with diseased periodontal conditions. Serotype c is a more common serotype detected in periodontally healthy subjects.

Possible Periodontal Pathogens Associated With Clinical Symptoms of Periodontal Disease in Japanese High School Students

BACKGROUND

The purpose of this study is to investigate how the components of biofilm and clinical oral status change in adolescents and to identify specific periodontal pathogens as risk markers for the onset of periodontitis.

METHODS

One hundred seven high school students (72 boys and 35 girls, all 15 years old) were recruited. The mesio-lingual site of the left lower first molar was selected as the examined site. Probing depth (PD), bleeding on probing (BOP), the presence of subgingival calculus, and Community Periodontal Index (CPI) were determined by examination with a WHO probe. The prevalence and proportion of seven selected periodontal pathogens (Porphyromonas gingivalis, Tannerella forsythensis, Prevotella intermedia, Campylobacter rectus, Eikenella corrodens, and Actinobacillus actinomycetemcomitans serotypes b and c) were determined by indirect immunofluorescent technique, and the prevalence and proportion of spirochetes were determined by their morphology under dark-field microscopy. The relationship between the periodontal status and the bacterial condition was statistically analyzed.

RESULTS

The mean proportion of T. forsythensis was significantly higher in BOP (+) sites compared with BOP (-) sites (3.47% +/- 5.35% versus 0.83% +/- 1.95%) and in CPI 3 sites compared with CPI 0 sites (3.29% +/- 5.28% versus 0.68% +/- 1.37%). The mean proportion of C. rectus was significantly increased in BOP (+) compared with BOP (-) (2.01% +/- 2.48% versus 0.79% +/- 0.91%) and in CPI 3 sites compared with CPI 0 sites (2.04% +/- 2.64% versus 0.80% +/- 0.79%).

CONCLUSION

The results indicated that T. forsythensis and C. rectus might be able to be used as risk markers for the onset of periodontitis.

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.

Occurrence of Actinobacillus actinomycetemcomitans in patients wearing orthodontic appliances. A cross-sectional study

The aim of the present study was to assess: (1) the occurrence of Actinobacillus actinomycetemcomitans (Aa) in subgingival plaque from young patients undergoing orthodontic treatment with fixed appliances; (2) a possible relationship between the presence of Aa and the clinical conditions; (3) a relation between the duration of orthodontic treatment and the microbiological and clinical parameters; (4) whether differences exist when taking into consideration the different type of appliances, i.e., bands or brackets. 34 subjects aged between 12 and 20 years participated in the study. Of these, 20 subjects had worn orthodontic appliances (test group), while the remaining 14 subjects served as matched control (control group). 4 to 8 sites in each patient were available for clinical and microbiological examination. Clinical parameters consisted of presence/absence of plaque and gingival bleeding index (GBI). Microbiological sampling was performed in the same sites as in the clinical examination. A statistically significant difference was present when comparing %s of GBI positive scores between teeth from the test group (57.5%) and teeth from the control group (25%). Plaque was present in 53% of test sites and 37% of control sites, but this difference was not statistically significant. Aa was detected from at least one site in 85% of test subjects and in 15% of the control subjects (p < 0.001). Among the subjects, 41% harboured Aa at a concentration between 0.1% and 1.0%, whereas another 40% yielded Aa at a concentration greater than 1.0%. Finally, a positive correlation was noted between the % of sites positive for Aa and the % of sites displaying a positive GBI score (r = 0.41; p < 0.005). No relation was found between the duration of orthodontic treatment and the microbiological or clinical parameters; neither were statistically significant differences found when we compared results from sites wearing bands or brackets. In conclusion, the present study showed that young subjects wearing orthodontic appliances harbour Aa with a remarkable frequency of detection, although plaque levels do not significantly differ from those of a matched control group.

Oral microbiota in subjects with a weak or strong response in experimental gingivitis

The purpose of the present study was to examine the composition of the oral microbiota in subjects who had previously demonstrated to develop either a weak or strong response to experimental gingivitis. For this study, subjects were selected from a pool of 25 individuals who had participated twice in an experimental gingivitis trial. Out of these 25 panellists, 6 subjects were selected who had developed 2X a weak gingival inflammatory response and 7 subjects who had developed 2X a strong gingival inflammatory response. Approximately 9 months after the 2nd experimental gingivitis trial, we evaluated the clinical condition and the prevalence of a panel of selected oral micro-organisms in these subjects. The subjects were clinically examined for the presence of plaque, bleeding, pocket depth and loss of attachment. For the microbiological evaluation, samples were taken from the mucous membranes, subgingival sites and saliva. Samples were analyzed for the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Peptostreptococcus micros, Actinomyces spp., Fusobacterium nucleatum, Campylobacter rectus, spirochaetes and motile rods. Clinical evaluation showed that most subjects had a relatively healthy periodontal condition. No clinically significant differences could be detected between the weak and strong responding groups. The microbial evaluation showed absence of A. actinomycetemcomitans, P. gingivalis and P. micros in all subjects in either group. Analysis of the microbial data for the weak and strong responding group showed no differences between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation frequency and serotype distribution of mutans streptococci and Actinobacillus actinomycetemcomitans, and clinical periodontal status in Finnish and Vietnamese children

The isolation frequency and serotype distribution of mutans streptococci and A. actinomycetemcomitans (A.a.) were investigated in a group of Finnish (n = 16) and Vietnamese (n = 16) children, matched by sex, age, and caries status. In the Vietnamese children, the isolation frequencies were higher than in the Finnish children: 100%/62% for mutans streptococci and 78%/13% for A.a. Isolates (n = 3-8) from plaque and saliva were serotyped by immunodiffusion technique using serotype-specific antisera against serotypes c, e, f, d, and g for mutans streptococci and a, b, c, d, and e for A.a. The distribution of mutans streptococci serotypes in Finnish/Vietnamese children was: c 100%/50%; e 10%/31%; d 0%/56%; g 20%/38%. The frequency of plural serotypes was 30%/75%, respectively. In the Vietnamese group the serotype distribution of A.a. was: a 36%, b 27%, and c 63%; 45% of children carried two serotypes. One Finnish child harbored serotype a and one serotype b. The mean percentage of bleeding gingival sites was 7.4 in the Finnish and 15.1 in the Vietnamese group. Calculus and clinically deepened gingival pockets were more frequent findings in the Vietnamese children. The results indicate considerable differences in bacteriologic status and in clinical periodontal status between these Finnish and Vietnamese children.

Prevalence of periodontitis and suspected periodontal pathogens in families of adult periodontitis patients

The aim of the present study was to investigate the prevalence of periodontopathic microorganisms and periodontal destruction in the spouses and children of adult periodontitis patients. For this study, 24 families were selected on the basis of one parent with severe periodontal breakdown and the presence of Actinobacillus actinomycetemcomitans and/or Porphyromonas gingivalis and/or more than 30% Prevotella intermedia subgingivally. The clinical examination of both parents and children included pocket depth and clinical attachment loss (CAL) measurements. Samples for bacterial examination were obtained from the mucous membranes, the saliva and pockets. Pocket selection was based on the most advanced periodontitis situation found in a subject. The samples were cultured for the detection of A. actinomycetemcomitans, P. gingivalis and P. intermedia. By phase-contrast microscopy, the % of spirochetes and motile microorganisms was assessed. The number of children within each family varied between 1 and 3. In total 49 children were investigated with a range in age of 3 months to 15 years. Results showed that under the age of 5 years, none of the children had CAL, whereas in the age group of 5-15 years, 26.5% had 1-5 sites in the primary and/or permanent dentition with 1-3 mm CAL. 3 of the spouses had no interproximal CAL. 16 of the 24 spouses had a light to moderate form of periodontitis, with at least one site with 1 to 4 mm CAL and 5 spouses had severe periodontal breakdown with sites showing at least 8 mm CAL. Spirochetes, motile microorganisms and P. intermedia were frequently present in all family members. 18 out of the 24 probands were positive for P. gingivalis. This organism was found once only in a 5-year-old boy and in 11 of the spouses. A. actinomycetemcomitans was detected in 13 probands; 5 children and 5 of the spouses were also positive for this bacterium. If a child harboured one of the periodontopathogens, at least 1 of the parents was also positive for that bacterium. This phenomenon may be due to transmission of microorganisms between family members. Comparison of the clinical data reported in the present study with similar clinical parameters from epidemiological studies of the Dutch population suggest that the spouses and children of adult periodontitis patients might be at relatively high risk of developing periodontal breakdown.

Transmission of Actinobacillus actinomycetemcomitans in families of adult periodontitis patients

At present Actinobacillus actinomycetemcomitans is regarded as an important microorganism in the etiology of some forms of periodontitis. The purpose of the present investigation was to study the number of Restriction Endonuclease Analysis (REA)-types present in the oral cavity of A. actinomycetemcomitans positive subjects and to study the possibility of transmission of A. actinomycetemcomitans within families of adult periodontitis patients. DNA of A. actinomycetemcomitans isolates was digested with a combination of the restriction endonucleases PstI and BamHI, after which the DNA fragments were separated by agarose gel-electrophoresis. To study the number of REA-types, multiple A. actinomycetemcomitans isolates obtained from 8 different sites in the oral cavity of five subjects were typed. The results showed that in most cases only one REA-type is present. In the 13 families investigated in 4 of the 26 children (15%) and in 1 of the 13 spouses (8%) of the adult periodontitis patients an indistinguishable REA-type was found within the families. This suggests that also in the case of adult periodontitis transmission of A. actinomycetemcomitans is possible, but does not seem to occur easily.

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.

Investigation of the influences of puberty, genetics, and environment on the composition of subgingival periodontal floras

The classical twin model was utilized in this study in an attempt to determine the importance of host genetics to the composition of the subgingival flora. Simultaneously, the effect of puberty on the flora composition was assessed. The compositions of the floras were significantly different at ages 11 and 14 in the same people, indicating that transition to an adult flora composition may be initiated during puberty. However, the numbers of subjects who had prepubertal and postpubertal testosterone levels in this study were too small to demonstrate significant differences based solely on testosterone level (P = 0.053 and 0.11 for tests of unrelated members, i.e., all twins "a," the first twin of each pair, and all twins "b," the second twin of each pair). Sixteen unrelated 11-year-old subjects had prepubertal levels of less than 30 ng of testosterone per dl of serum, and only six of these unrelated subjects had levels above 300 ng/dl by age 14. Of their twin siblings, who formed the second group of unrelated individuals, 15 had prepubertal levels and only 5 reached postpubertal levels. Unpaired t tests indicated that Veillonella atypica, Prevotella denticola, and Prevotella melaninogenica were among the species that contributed most to changes in flora composition during puberty. The compositions of subgingival floras of 11-year-old monozygous and dizygous male twins were significantly more similar than those of unrelated subjects in the study (P = 0.004 and 0.009, respectively). At 12.5 years of age, the floras of monozygous twins remained more similar than those of unrelated subjects (P = 0.001), but the dizygous-twin floras were not significantly more similar than those of unrelated people. This difference corresponded with moderate and varied testosterone levels within dizygous-twin pairs at age 12.5. By age 14 both monozygous and dizygous twins again had floras with compositions more similar than those of unrelated people (P = 0.008 and 0.002, respectively). Estimates of the genetic contributions to the increased similarity of the floras of twins as compared with floras of unrelated people indicated that the concentrations of several species in the flora may be influenced by host genetic factors. The prevalence of certain other species appeared to be controlled primarily by environment.

The age-dependence of bacterial presence on oral epithelial surfaces in vivo

Epithelial cells obtained by gentle scraping with a brush tip from the gingival margin of d 11 or 51, adjacent labial mucosa and buccal mucosa of children, adolescents and adults were stained with acridine orange and examined under a fluorescence microscope. The amount of bacteria appearing on the epithelial cells was assessed and the form of the adhered bacteria was evaluated. An age-related descending trend (negative Pearson's r in all sites) could be seen in the number of colonized cells (> 50 bacteria present) in gingival, labial and buccal areas. Adolescents and adults had significantly fewer epithelial cells with colonization of bacteria in the labial and buccal areas compared with children under 6 years. Only cocciformed bacteria were seen associated with the epithelial cells. By studying bacterial adhesion according to methods outlined in the present study, it should be possible to more closely investigate the bacteria-host relationships as they appear in nature.

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

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

Proximal attachment loss in Swedish adolescents

The present study describes periodontal conditions in 22 adolescents with proximal attachment loss greater than or equal to 2 mm (AL) and 22 matched referents without AL, all identified in a cross-sectional study of 570 16- and 18-year-old. The cases were followed for 3 years and the referents for 1 year while they were in the care of an organized dental health system. With the exception of 1 case with Morbus Hodgkin, the case and referent groups had a similar background with respect to general health and participation in the dental health program. Bleeding on probing was found at AL sites in 12 of the cases and at corresponding sites in 4 referents. 2 cases had a history of eruption disorders at the AL sites, 1 case had experienced a defective filling and 1 had a root fissure at the AL sites. At re-examinations after 1 and 3 years, 10 out of 21 earlier identified AL cases did not meet the criterion of 1 or more sites with AL greater than or equal to 2 mm. None of the cases showed progression greater than or equal to 2 mm of the lesions. In 1 case, the number of AL sites increased during the period. 4 of the cases harboured Actinobacillus actinomycetemcomitans (A.a.) at AL sites in year 1 and 3 in year 3. 8 of the cases and 4 referents had antibodies specific for A.a.-leukotoxin. The 2 most severe cases, in terms of number of sites with AL, showed bleeding at 1 or more of the AL sites, harboured A.a. at these sites and had serum titers against A.a.-leukotoxin.

Are certain oral pathogens part of normal oral flora in denture-wearing edentulous subjects?

A complete loss of teeth may eliminate some pathogenic bacteria for lack of a suitable habitat for colonization. The occurrence of Actinobacillus actinomycetemcomitans, black-pigmented Bacteroides, mutans streptococci, lactobacilli and yeasts was investigated in 51 edentulous subjects with complete denture(s); mean age 74 years (range 44-92 years). None of the subjects had received antibiotics during the preceding 6 months. Four swab samples per subject were taken from the fitting surface of the upper denture, from the palate, buccal mucosae and dorsum of the tongue. At least 0.5 ml of stimulated saliva was collected into a sterile tube. The samples were cultivated aerobically and anaerobically using nonselective and selective media. A. actinomycetemcomitans was not found in any of the samples. Black-pigmented Bacteroides were found in 49 (96%) and yeasts in 25 (49%) of the subjects. Of the 49 saliva samples, 41 (84%) yielded mutans streptococci and 45 (92%) lactobacilli. In contrast to black-pigmented Bacteroides, mutans streptococci and lactobacilli, A. actinomycetemcomitans may not belong to the normal oral flora of edentulous subjects wearing dentures.

A 2-year follow-up on the clinical and microbiological conditions of periodontium in teenagers

87 teenagers were included in a 2-year follow-up study on clinical and microbiological conditions of the periodontium. The clinical status was determined according to the Community Periodontal Index of Treatment Needs (CPITN) for subjects under 20 years of age. 59% of the subjects had at least 3 healthy sextants at the baseline and 68% at the 2-year examination. The microbiological conditions were assessed by using direct dark-field microscopy, and the culture of Actinobacillus actinomycetemcomitants (A.a.). Subgingival bacterial samples were taken, 2 for the microscopy and 2 for the culture, from the mesial surfaces of the first molars of each subject. The presence of gingival bleeding after probing was separately recorded from the 2 sites sampled for dark-field microscopy. No gingival bleeding at these 2 sites was found at the 2-year examination in 55% of those subjects who were non-bleeding at baseline, in 46% of the subjects initially with 1 bleeding site and in 13% of the subjects with both sites bleeding at baseline. 55% of the subjects with neither fusiforms, motile rods nor spirochetes at baseline maintained their healthy flora for 2 years. A.a. was recovered in 4 subjects at baseline and in 5 subjects 2 years later, in 3 of them at both examinations. Longer follow-up periods are needed to reveal the significance of the constant recovery of A.a. from the same subjects.

Changes in subgingival microbiota during puberty. A 4-year longitudinal study

It was the purpose of the present investigation to monitor the composition of the subgingival microbiota at selected sites in individuals passing through puberty and to correlate observed changes with the development of pubertal maturation. Between the ages of 11 and 14 years, pubertal and skeletal maturation was monitored annually in 22 boys and 20 girls. During this time, subgingival microbial samples were taken every 4th to 5th month (10 times in 4 years) mesially of the upper first molars. High values in total bacterial counts were reached after the onset of puberty, followed by a decrease towards the end of the observation period. The frequency of detection of Actinomyces odontolyticus and of Capnocytophaga sp. increased with time. The frequencies of other selected species, specifically of black pigmenting Bacteriodes sp. were not found to increase when tested by linear and quadratic models of time trend. However, a statistically significant rise in the frequency of detecting B. intermedius and B. melaninogenicus was noted in the initial pubertal phase identified by the onset of testicular growth in boys (p = 0.05). A significant relationship also existed between testes growth and increase of A. odontolyticus (p less than 0.01). In girls, a similar increase was obtained for A. odontolyticus when studied in relation to the Tanner scores for breast development (p less than 0.01). The changes observed in the subgingival microbiota during puberty may be related to the development of gingivitis, which was demonstrated by a higher tendency for gingival bleeding during the course of the pubertal maturation process.

Microbial changes associated with the development of puberty gingivitis

In this study, longitudinal changes in the composition of the subgingival microbiota of children between the ages of 11 and 14 and their association with changes of clinical parameters describing gingival health were investigated. During 4 years, subgingival microbial samples were taken in 22 boys and 20 girls 10 times. At the same time the gingival bleeding tendency was recorded by the Papillary Bleeding Index (PBI). A total of 840 samples was evaluated using darkfield microscopy and anaerobic culturing on non-selective and selective media. Children, who developed a marked and sustained increase in mean PBI scores (n = 21), had higher frequencies and mean proportions of spirochetes and Eikenella corrodens than children without pronounced puberty gingivitis (p less than = 0.05). The mean proportion of Actinomyces viscosus was also higher in these children (p less than = 0.05). Among the species discriminated, only Capnocytophaga sp. were found at a higher rate in samples taken immediately before a rise of PBI (p less than = 0.05). The detection frequencies of black-pigmented Bacteroides (particularly B. intermedius) increased later, and were significantly elevated after the establishment of a high bleeding tendency (p less than = 0.05). These findings implicate Capnocytophaga sp. in the initiation of puberty gingivitis, whereas the increased presence of Bacteroides may reflect a change in the subgingival environment secondary to increased bleeding.

Subpopulations of lymphocytes in connective tissue from adolescents with periodontal disease

Mononuclear cell populations were studied in gingival biopsy specimens from adolescents (n = 10) with at least one periodontal pocket with an increased probing depth (greater than 5 mm). The marginal bone loss was measured on radiographs, subgingival plaque samples were collected from the lesions, and the microbial flora was identified. Specimens from gingivitis lesions (n = 5) were used as controls. The mononuclear cell populations in the specimens were detected by using monoclonal antibodies defining functional T-lymphocyte subpopulations, B lymphocytes, and monocytes. All gingival specimens from patients with increased probing depth showed large lymphocyte infiltrates, most of which were CD 3-antigen-positive cells (T lymphocytes). Few (2%) infiltrating T cells expressed receptors for interleukin-2. B cells were detected in most specimens from the periodontitis group and varied from less than 1% to 21%. This study indicates that lesions in adolescents with early signs of periodontitis are characterized predominantly by T-cell lesions with relatively few cell aggregates of B cells present.

Prevalence of periodontal breakdown in adolescents and presence of Actinobacillus actinomycetemcomitans in subjects with attachment loss

The present investigation was carried out to study the prevalence and clinical appearance of destructive periodontal disease in a school population of 15- to 16-year old adolescents in Amsterdam. In addition the prevalence of Actinobacillus actinomycetemcomitans was studied in those subjects showing attachment loss. Attachment loss was diagnosed in 230 of the 4565 subjects participating which is about 5% of the population studied. Within this population males were more frequently affected than females (P = 0.008). Extensive periodontal destruction was found in 16 subjects (0.3%). In this group a female/male ratio was found of 1.3:1. As a result of the epidemiological survey, 105 subjects with attachment loss volunteered for further investigation. The results showed that presence of plaque, redness and swelling of the gingiva, and bleeding on probing were general phenomena. In addition, the bleeding/plaque ratio, as determined for each subject at sites without attachment loss, increased with the severity of periodontal disease as expressed by the number of sites with attachment loss (P = 0.0038) as well as by the amount of destruction at these sites (P = 0.002). A. actinomycetemcomitans could be identified in 18 of the 105 subjects with attachment loss. Analysis showed that A. actinomycetemcomitans was more frequently isolated in subjects with moderate to severe periodontal breakdown than in subjects with mild breakdown (P less than 0.02). When estimating the percentage of juvenile periodontitis patients on the basis of the classically accepted criteria, it seems likely that between 0.1% to 0.2% of the population in Amsterdam is suffering from this disease entity.

Black-pigmented Bacteroides species and Actinobacillus actinomycetemcomitans in subgingival plaque of adult Kenyans

A microbiological study was performed of the subgingival plaque on 2 sites in each of 20 adults originating from a rural area 40 km outside Nairobi, Kenya. The recovery rate of B. gingivalis was 70%, of B. intermedius 100% and of A. actinomycetemcomitans 40% of the subjects, and 50%, 90% and 28%, respectively, of the sites. The isolated strains exhibited similar biochemical characteristics and antibiotic susceptibility pattern as type strains of these species. The high recovery rate of these 3 bacterial species in adult Kenyans was a rather surprising finding, since pathological pocketing was found only sporadically. Furthermore, the results of 2 methodological approaches tested demonstrated that such microbiological studies can be carried out in countries with limited laboratory facilities.

Detection and distribution of Actinobacillus actinomycetemcomitans in the primary dentition

The occurrence of actinobacillus actinomycetemcomitans (A.a.) in plaque samples from the primary dentition was studied in 55 healthy Finnish children from four to seven years of age. A.a. was isolated in seven (13%) children, four boys and three girls. A further examination of the distribution and infection level of A.a. in the oral cavity of five of the A.a.-positive children revealed that A.a. was found in 26 of 45 plaque samples (7-10 samples from each child) and in all samples obtained from the dorsum of the tongue. The individual detection rates of A.a. were 3/7, 5/10, 6/10, 6/10 and 6/8 of the dental sites examined. A.a. occurred in 9/10 of the second primary molars, 8/10 of the first primary molars, 5/10 of the cuspids, 4/8 of the upper incisors and in none of the lower incisors examined. The proportions of A.a. within the dentition had a wide range. In 58% of the A.a.-positive samples, the proportions were less than 1%, and none exceeded 10% of the flora. Gingival bleeding after sampling with floss occurred more than twice as frequently in the A.a.-positive as in the A.a.-negative sites (16%/42%). The results indicate that A.a. was a rather frequent member of the oral flora in the children with primary teeth. The primary molars and the dorsum of the tongue seemed to be preferred sites for A.a. More than one site should be sampled to determine the infection level of A.a. within the dentition.