Subgingival spirochete and leukocyte counts as indicators of response to therapy

The aim of this study was to determine whether changes in probing attachment levels are related to subgingival spirochete or leukocyte counts in periodontal pockets. Following initial clinical recordings and therapy consisting of oral hygiene instruction and root debridement, the probing attachment levels of proximal sites of 120 single-rooted teeth in 7 patients were measured every 3 months for 12 months. The measurements of each site were subjected to regression analysis, which determined whether the site was deteriorating, improving, or non-changing. Subgingival washings were taken of 19 deteriorating, 22 improving, and 127 non-changing sites to determine the number and % of spirochetes and the number of leukocytes at each site. Improved probing attachment levels were associated with reduced numbers of spirochetes and leukocytes. However, the ranges of individual measurements of subgingival washing variables overlapped considerably between groups. Spirochete and leukocyte counts related better to the 12-month probing depths than to changes in probing attachment levels during the preceding 12 months. These findings suggest that none of the tested subgingival washing parameters are suitable indicators of changes in attachment levels on an individual site basis.     

The effect of supragingival plaque control on the subgingival microbiota in subjects with periodontal disease

The present investigation was performed to study the effect on the subgingival microbiota, of a plaque control program which included meticulous oral hygiene instruction, supragingival scaling and professional monitoring during a 2 year period. 300 subjects were examined for periodontal disease and monitored for 2 years without treatment. After the 2 year examination, 80 subjects were invited to participate in a treatment program intended to improve the standard of their self-performed plaque control. 40 of the invitees had a gingivitis and only minor attachment loss, while 40 subjects had moderate signs of periodontitis. 62 subjects volunteered for this treatment. 23 of the volunteers (Group AB) had several sites with deep pockets (> 4 mm). 39 of the volunteers had gingivitis but shallow pockets only (Group C). Group AB contributed 31 shallow pocket sites (A-sites) and 40 deep pocket sites (B-sites), while Group C contributed 63 shallow sites (C-sites). After the clinical examination, samples of the subgingival microbiota were harvested from the 134 A, B and C sites. The 62 subjects were enrolled in a supervised oral hygiene program. Supragingival scaling was carried out. Oral hygiene instruction was provided and repeated on an individual need basis so that all subjects reached and maintained a supragingival plaque score which was < 20%. 24 months after the year 2 examination, the 62 subjects were examined again using both clinical and microbiological examination procedures. The findings demonstrated that carefully performed supragingival plaque control changed the quantity and the composition of the supragingival microbiota.(ABSTRACT TRUNCATED AT 250 WORDS)     

Microbiological profile of untreated subjects with localized aggressive periodontitis

Aim: The microbial profile of localized aggressive periodontitis (LAgP) has not yet been determined. Therefore, the aim of this study was to evaluate the subgingival microbial composition of LAgP.
Material and Methods: One hundred and twenty subjects with LAgP ( n =15), generalized aggressive periodontitis (GAgP, n =25), chronic periodontitis (ChP, n =30) or periodontal health (PH, n =50) underwent clinical and microbiological assessment. Nine subgingival plaque samples were collected from each subject and analysed for their content of 38 bacterial species using checkerboard DNA–DNA hybridization.
Results: Red complex and some orange complex species are the most numerous and prevalent periodontal pathogens in LAgP. The proportions of Aggregatibacter actinomycetemcomitans were elevated in shallow and intermediate pockets of LAgP subjects in comparison with those with GAgP or ChP, but not in deep sites. This species also showed a negative correlation with age and with the proportions of red complex pathogens. The host-compatible Actinomyces species were reduced in LAgP.
Conclusion: A. actinomycetemcomitans seems to be associated with the onset of LAgP, and Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Campylobacter gracilis, Eubacterium nodatum and Prevotella intermedia play an important role in disease progression. Successful treatment of LAgP would involve a reduction in these pathogens and an increase in the Actinomyces species.     

The use of DNA probes to examine the distribution of subgingival species in subjects with different levels of periodontal destruction

The present investigation examined the distribution of 14 subgingival species at a total of 2299 sites in 90 subjects with different levels of periodontal destruction. Subgingival plaque samples taken from the mesial aspect of each tooth were anaerobically dispersed, diluted and plated on non selective media. After anaerobic incubation, colonies were lifted to nylon filters and specific species detected using digoxygenin-labeled whole chromosomal DNA probes. The mean total viable count for all sites in all subjects was 8.3 x 10(6). The probes accounted for an average of 27.8% of the total viable count. The % of subjects in which each species was detected was as follows; V. parvula, 98; B. intermedius I, 98; S. sanguis II, 96; B. intermedius II, 95; C. ochracea, 94; B. gingivalis, 91; S. sanguis I, 85; W. recta, 83; F. nucleatum ss. vincentii, 82; S. intermedius, 80; B. forsythus, 76; P. micros, 74; A. actinomycetemcomitans serotype a, 62 and A. actinomycetemcomitans serotype b, 52. The % of sites colonized by each of the 14 test species varied considerably within different subjects. The median number of sites colonized by different species ranged from 3.6% for A. actinomycetemcomitans serotype b to 43.5% for V. parvula. In half the subjects, the mean % of the total viable counts for each of the test species was less than 4%. When subjects were divided on the basis of % of sites at baseline with greater than 3 mm attachment loss, the 14 probes accounted for 29.9% of the microbiota in the localized disease group and 25% in the widespread disease group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Subgingival microbiota of periodontally untreated Mexican subjects with generalized aggressive periodontitis

BACKGROUND AND AIM: Specific microbial profiles that may distinguish between generalized aggressive-periodontitis (GAgP) and generalized chronic-periodontitis (GCP) have, to date, not been described. The purpose of the present study was to describe the subgingival microbial composition of Mexican subjects with GAgP and compare it with that of individuals with GCP and periodontal health (PH). MATERIAL AND METHODS: Seventy-seven subjects with GAgP (n=19), GCP (n=39) and PH (n=19) were selected. Clinical measurements included plaque accumulation, gingival erythema, bleeding on probing, suppuration, pocket depth and attachment level. Up to 28 subgingival plaque samples were obtained from each subject and analysed using the checkerboard DNA-DNA hybridization technique. RESULTS: GAgP and GCP subjects harboured significantly higher levels and/or proportion of Porphyromonas gingivalis, Tannerella forsythia (levels: p<0.001, proportion: p<0.01), Prevotella nigrescens (p<0.05 levels) and "red" complex species (p<0.001 proportion) than PH subjects. All GAgP subjects were carriers of P. gingivalis and P. nigrescens. No significant differences in any of the 40 microbial species tested were detected between GAgP and GCP subjects. CONCLUSIONS: Our results revealed that the microbial differences between GAgP and GCP subjects were only discrete and none of the bacterial species tested seemed to specifically differentiate the subgingival microbial profile of either periodontitis group.     

Subgingival biodiversity in subjects with uncontrolled type‐2 diabetes and chronic periodontitis

Background and Objective: There is a bidirectional relationship between periodontal disease and type‐2 diabetes mellitus (DM). Inflammatory mediators may negatively affect glycemic control, and increased glucose levels and resultant glycation end‐products may alter the host response against bacterial infection. However, no agreement has been reached regarding the effect of DM on periodontal subgingival microbiota. Therefore, the purpose of the present study was to compare the subgingival biodiversity in deep periodontal pockets of subjects with chronic periodontitis and either uncontrolled type‐2 diabetes or no diabetes using 16S rRNA gene cloning and sequencing. Material and methods: Twelve subjects with uncontrolled type‐2 diabetes (glycated hemoglobin > 8%) and eleven nondiabetic subjects presenting severe and generalized chronic periodontitis were selected. Subgingival biofilm from periodontal pockets > 5 mm were assessed using the 16S rRNA gene cloning and sequencing technique. Results: Significant differences were observed in subgingival microbiota between diabetic and nondiabetic subjects. Diabetic subjects presented higher percentages of total clones of TM7, Aggregatibacter, Neisseria, Gemella, Eikenella, Selenomonas, Actinomyces, Capnocytophaga, Fusobacterium, Veillonella and Streptococcus genera, and lower percentages of Porphyromonas, Filifactor, Eubacterium, Synergistetes, Tannerella and Treponema genera than nondiabetic individuals (p < 0.05). Moreover, some phylotypes, such as Fusobacterium nucleatum, Veillonella parvula, V. dispar and Eikenella corrodens were detected significantly more often in diabetic subjects than in nondiabetic subjects (p < 0.05). Conclusion: Subjects with uncontrolled type‐2 diabetes and chronic periodontitis presented significant dissimilarities in subgingival biodiversity compared with nondiabetic subjects.     

Repeated subgingival oxygen irrigations in untreated periodontal patients

Abstract The aim of this study was to assess the effect of repeated subgingival oxygen irrigations in previously untreated deep periodontal pockets. 112 pockets ≥4 mm were selected in 14 subjects. Probing attachment level and bleeding on probing were recorded, as well as the presence of disease-associated microorganisms within the pocket. Subsequently, the pockets were irrigated with gaseous oxygen 1 × a week during a continuous 8-week period. Irrigations with nitrogen served as control. The re-evaluation of all clinical and microbiological parameters at the end of study revealed that repeated oxygen insufflations resulted in a significant clinical improvement of the periodontal baseline conditions superior to the one found in the control.     

Utility of 5 major putative periodontal pathogens and selected clinical parameters to predict periodontal breakdown in patients on maintenance care

Abstract The predictive utility of 5 major putative periodontopathic microbial species, “superinfecting” organisms, and several clinical periodontal parameters were assessed relative to periodontitis recurrence over a 12-month period in 78 treated adult patients participating in a 3-month maintenance care program. At baseline, pooled subgingival microbial samples were collected from each patient, and whole-mouth evaluations of probing depth, relative periodontal attachment level, furcation involvement, and indices of plaque and gingival inflammation were carried out. 67 (85.9%) subjects were culture-positive at baseline for presence of either Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia. Campylobacter rectus or Peptostreptococcus micros, with 48 (61.5%) subjects yielding one or more of these species at or above designated threshold proportions of ≥0.01% for A. actinomycetemcomitans, ≥0.1% for P. gmgivalis, ≥2.5% for P. intermedia, ≥2.0% for C. rectus, and ≥3.0% for P. micros. Subgingival yeasts were recovered from 12 subjects, staphylococci from 7, and enteric rods/pseudomonads from 6; however, no subjects revealed 21.0% baseline proportions of these “superinfecting” organisms in subgingival specimens. Periodontitis recurrence in subjects was defined as any periodontal site exhibiting either a probing depth increase of 2:3 mm from baseline, or a probing depth increase of 22 mm from baseline together with a loss in relative periodontal attachment of 22 mm from baseline. 15 (19.2%) study subjects showed periodontitis recurrence within 6 months of baseline, and 25 (32.1%) within 12 months. The mere baseline presence of the 5 major test species and “superinfecting” organisms were not significant predictors of periodontilis recurrence over 12 months. However, a 2.5 relative risk for periodontitis recurrence over 12 months was found for subjects yielding one or more of the 5 major test species at or above the designated baseline threshold proportions (p=0.022. Mantel-Haenszel %2 test). The positive predictive value for periodontitis recurrence of a microbiologic analysis encompassing the 5 major test species at or above the designated threshold proportions improved with increasing time from baseline, up to approximately 42% at 12 months. Baseline variables jointly providing in multiple regression analysis the best predictive capability for periodontitis recurrence in subjects over a 12-month period were recovery of one or more of the 5 major test species at or above designated threshold proportions, the proportion of sites per subject with 25 mm probing depth, and the mean whole-mouth probing depth. These findings indicate that one or more of 5 major putative periodontal pathogens in elevated subgingival proportions together with increased probing depth predispose adults on maintenance care to recurrent periodontitis.     

The predominant cultivable microbiota of active and inactive lesions of destructive periodontal diseases

Subgingival plaque samples were taken from active and inactive lesions in 33 subjects exhibiting active destructive periodontal diseases. Active diseased sites were those which showed a significant loss of attachment within a 2-month interval as computed by the "tolerance method". The predominant cultivable species from 100 active sites were compared with those found in 150 inactive sites of comparable pocket depth and attachment level loss. Among the 33 subjects, W. recta, B. intermedius, F. nucleatum, B. gingivalis and B. forsythus were elevated more often in active sites; whereas, S. mitis, C. ochracea, S. sanguis II, V. parvula and an unnamed Actinomyces sp. were elevated in inactive sites. The likelihood of a site being active was increased if B. forsythus, B. gingivalis, P. micros, A. actinomycetemcomitans, W. recta, or B. intermedius were detected in that site, and decreased if S. sanguis II, the Actinomyces sp., or C. ochracea were detected.     

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

BACKGROUND AND AIMS: Bacteria play an essential role in the pathogenesis of destructive periodontal disease. It has been suggested that not all bacteria associated with periodontitis may be normal inhabitants of a periodontally healthy dentition. In particular, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans have been isolated infrequently from subjects without periodontitis. The aim of the present study was to compare prevalence and proportions of a number of periodontal bacteria in periodontitis patients and control subjects. MATERIAL AND METHODS: In all, 116 consecutive subjects diagnosed with moderate to severe periodontitis (mean age 42.4) and 94 subjects without radiographic evidence of alveolar bone loss (mean age 40.4) were recruited for the study. The gingival condition in the control group varied between gingival health and various degrees of gingivitis. In patients, the deepest pocket in each quadrant was selected for microbiological sampling. In control subjects all mesial and distal sites of all first molars were selected for sampling. All paper points from a patient were pooled and processed for anaerobic cultivation within 6 h after sampling. Clinical variables of sampled sites included bleeding index, probing pocket depth and clinical attachment level. RESULTS: A. actinomycetemcomitans, P. gingivalis, Prevotella intermedia, Bacteroides forsythus, Fusobacterium nucleatum and Peptostreptococcus micros were significantly more often prevalent in patients than in controls. The highest odds ratios were found for P. gingivalis and B. forsythus (12.3 and 10.4 resp.). Other odds ratios varied from 3.1 to 7.7 for A. actinomycetemcomitans and P. micros, respectively. Absolute numbers of target bacteria were all higher in patients, but only the mean percentage of B. forsythus was significantly higher in patients in comparison to controls (P < 0.001). CONCLUSIONS:A. actinomycetemcomitans, P. gingivalis, P. intermedia, B. forsythus, F. nucleatum and P. micros are all significant markers for destructive periodontal disease in adult subjects. Based on calculated odds ratios, B. forsythus and P. gingivalis are the strongest bacterial markers for this disease and are infrequently cultured from subjects without periodontal bone loss.     

Longitudinal changes in periodontal disease in untreated subjects

About 300 subjects, 20-79 years of age were recruited for a longitudinal study on the effect of periodontal therapy. The result of a baseline examination have been reported earlier. Following this baseline examination, the subjects were monitored for 24 months without therapy. Re-examinations were performed after 12 and 24 months. All teeth including the 3rd molars were included in the examinations. Presence of plaque was assessed at 4 surfaces per tooth and gingivitis, probing pocket depth, probing attachment levels were assessed at 6 locations per tooth. Out of the subject sample examined at baseline, 57 individuals failed to return for either the 1st, the 2nd or both re-examinations. An analysis was performed regarding the periodontal status at baseline, of the respondents and non-respondents. The results from the follow-up examinations of the participating 20 to 79 year-old subjects revealed that the sample underwent, during a 2-year period, only minor changes with respect to a series of different parameters characteristic of periodontal disease. Thus, the mean values of probing pocket depth and probing attachment level failed to change between baseline and the re-examinations after 1 and 2 years. Even if the mean values underwent only minor changes, however, certain subjects within each age category improved their periodontal conditions, whereas other subjects worsened. Furthermore, the findings of the re-examinations revealed that there was a strong correlation between improving plaque levels and gingivitis. The relationship between supragingival plaque levels and changes with respect to probing depth and attachment levels were weak.     

Differences in the subgingival microbiota of Swedish and USA subjects who were periodontally healthy or exhibited minimal periodontal disease

BACKGROUND: Previous studies have shown differences in the mean proportions of subgingival species in samples from periodontitis subjects in different countries, which may relate to differences in diet, genetics, disease susceptibility and manifestation. The purpose of the present investigation was to determine whether there were differences in the subgingival microbiotas of Swedish and American subjects who exhibited periodontal health or minimal periodontal disease. METHOD: One hundred and fifty eight periodontally healthy or minimally diseased subjects (N Sweden=79; USA=79) were recruited. Subjects were measured at baseline for plaque, gingivitis, BOP, suppuration, pocket depth and attachment level at 6 sites per tooth. Subgingival plaque samples taken from the mesial aspect of each tooth at baseline were individually analyzed, in one laboratory, for their content of 40 bacterial species using checkerboard DNA-DNA hybridization (total samples=4345). % DNA probe counts comprised by each species was determined for each site and averaged across sites in each subject. Significance of differences in proportions of each species between countries was determined using ancova adjusting for age, mean pocket depth, gender and smoking status. p values were adjusted for multiple comparisons. Cluster analysis was performed to group subjects based on their subgingival microbial profiles using a chord coefficient and an average unweighted linkage sort. RESULTS: On average, all species were detected in samples from subjects in both countries. After adjusting for multiple comparisons, 5 species were in significantly higher adjusted mean percentages in Swedish than American subjects: Actinomyces naeslundii genospecies 1 (9.7, 3.3); Streptococcus sanguis (2.5, 1.2); Eikenella corrodens (1.7, 1.0); Tannerella forsythensis (3.5, 2.3) and Prevotella melaninogenica (6.3, 1.8). Leptotrichia buccalis was in significantly higher adjusted mean percentages in American (5.5) than Swedish subjects (3.0). Cluster analysis grouped 121 subjects into 8 microbial profiles. Twenty four of the 40 test species examined differed significantly among cluster groups. Five clusters were dominated by American subjects and 2 clusters by Swedish subjects. Fifty eight of 79 (73%) of the Swedish subjects fell into 1 cluster group dominated by high proportions of A. naeslundii genospecies 1, Prevotella nigrescens, T. forsythensis and P. melaninogenica. Other clusters were characterized by high proportions of Actinomyces gerencseriae, Veillonella parvula, Capnocytophaga gingivalis, Prevotella intermedia, Eubacterium saburreum, L. buccalis and Neisseria mucosa. CONCLUSIONS: The microbial profiles of subgingival plaque samples from Swedish and American subjects who exhibited periodontal health or minimal disease differed. The heterogeneity in subgingival microbial profiles was more pronounced in the American subjects, possibly because of greater genetic and microbiologic diversity in the American subjects sampled.     

The effect of supragingival plaque control on the progression of advanced periodontal disease

Abstract. The aim of the present trial was to study the effect of meticulous supragingival plaque control on (i) the subgingival microbiota, and (ii) the rate of progression of attachment loss in subjects with advanced periodontal disease. An intra-individual group of sites exposed to non-surgical periodontal therapy served as controls. 12 patients with advanced periodontal disease were subjected to a baseline examination (BL) including assessments of oral hygiene status, gingival condition (BoP), probing depth, clinical attachment level and subgingival microbiota from pooled samples from each quadrant. The assessments were repeated after 12, 24 and 36 months. Following BL, a split mouth study was initiated. The patients received oral hygiene instruction, supragingival scaling and case presentation. 2 quadrants in each patient were identified as “test” and the remaining 2 as “control” quadrants. Subgingival therapy was performed in all bleeding sites in the control quadrants. Oral hygiene instructions and plaque control exercises were repeated once every 2 weeks during the initial 3 months of the study. Thereafter the plaque control program was repeated once every 3 months for the duration of the 3 years. Sites demonstrating loss of clinical attachment ≥2 mm in the test quadrants were treated subgingivally. The results showed that in both test and control quadrants repeated oral hygiene instructions and supragingival plaque removal procedures resulted in low plaque scores throughout the study. The gingival bleeding scores and the frequency of periodontal pockets ≥4 mm was, however, significantly higher in the test quadrants than in the control quadrants. At the end of the 3 year study, the control quadrants showed significantly more reduced (≥2 mm) pockets than the test quadrants, 265 versus 96. The number of sites in the test quadrants showing probing attachment loss ≥2 mm was more than 4× greater than in the control quadrants (59 versus 13). The microbiological findings indicate a more pronounced reduction only for P. gingivalis in the control quadrants. None of the other 4 marker bacteria consistently reflected or predicted the clinical parameters. The present study shows that only supragingival plaque control fails to prevent further periodontal tissue destruction in subjects with advanced periodontal disease.     

Predominant microflora of severe, moderate and minimal periodontal lesions in young adults with rapidly progressive periodontitis

The purpose of this investigation was to study the microflora of severe, moderate and minimal periodontal lesions, in young adults with rapidly progressive periodontitis (RPP). Subgingival plaque samples were taken from 142 periodontal lesions in 10 young adults aging 25 to 35 years. The examination of the subgingival microflora indicated that certain species, including Porphyromonas gingivalis, Bacteroides forsythus, Fusobacterium nucleatum, Actinobacillus actinomycetemcomitans , and Campylobacter species were found to be predominant in severe periodontal lesions. B. forsythus, P. gingivalis, Prevotella intermedia, F. nucleatum, Capnocytophaga ochracea , were predominant in medium lesions while Streptococcus species and Actinomyces species, C. ochracea, Haemophilus segnis and Veillonella parvula , were found in higher levels in minimal periodontal lesions.     

Relation of counts of microbial species to clinical status at the sampled site

The purpose of the present investigation was to relate clinical characteristics at a site to the frequency of detection, absolute counts and proportions of 14 subgingival species. Subgingival plaque samples were removed by curette from the mesial surface of 2299 teeth in 3 healthy and 87 subjects with periodontal attachment loss. Samples were dispersed, diluted and plated on Trypticase soy agar supplemented with 5% sheep blood. After 7 days of anaerobic incubation, colonies were lifted onto nylon filters, lysed and the DNA fixed to the filters. Digoxygenin-labeled DNA probes were used to identify colonies of each test species. Measurements of pocket depth, attachment level, recession, redness, bleeding on probing and suppuration were made at each sampled site. Total viable counts at sites ranged from 10(3) to greater than 10(8) and were strongly related to pocket depth. Mean total counts at sites less than 3 mm averaged 4.6 x 10(6), while mean counts at sites greater than 7 mm averaged 2.0 x 10(7). Species enumerated and % of sites colonized were as follows; V. parvula 44; S. sanguis II 36; B. intermedius I 33; C. ochracea 31; B. intermedius II 30; S. sanguis I 29; B. gingivalis 27; S. intermedius 25; P. micros 24; W. recta 23; F. nucleatum ss vincentii 18; B. forsythus 15; A. actinomycetemcomitans serotype a 10; A. actinomycetemcomitans serotype b 8. Counts of B. intermedius II were higher at sites which exhibited gingival redness while B. intermedius I was higher at sites which bled on probing. A. actinomycetemcomitans serotype b was more frequent and at higher mean % at sites without recession. The opposite was true for S. sanguis II. B. gingivalis was somewhat more prevalent and at higher levels at suppurating sites. B. gingivalis, B. intermedius I and II and B. forsythus were found more frequently and at higher levels at sites with deeper pockets, while V. parvula was less prevalent at sites with pocket depths less than 4 mm. B. gingivalis, B. intermedius I and A. actinomycetemcomitans serotype b increased with increasing pocket depth in both localized and widespread disease subjects, but mean counts were higher in the localized disease subjects at any pocket depth. Only W. recta was found at higher levels at deep sites in widespread disease subjects when compared with similar sites in localized disease subjects. No suspected pathogens were detected in 38% of shallow sites, 31% of intermediate sites and 22% of deep sites, 2/3 of deep pockets, but less than 1/2 of shallow pockets harbored at least 2 of the suspected pathogens.     

The effect of subgingival debridement on periodontal disease parameters and the subgingival microbiota

Abstract The aim of the present investigation was to analyse the effect of subgingival scaling and root planing in subjects who prior to treatment exercised meticulous supragingival plaque control. 300 subjects were examined at baseline and after 1 and 2 years without treatment. After the year 2 examination, 62 subjects were randomly selected for therapy. They were given detailed instruction in proper self-performed toothcleaning measures and were carefully monitored during the subsequent 2 years. Following the year-4 examination, 2 quadrants, 1 maxillary and 1 mandibular in each subject, were randomly selected for additional therapy. The teeth in the selected quadrants were exposed to subgingival scaling and root planing. The subgingival therapy was repeated until a site no longer bled on gentle probing. This basic therapy was completed within a 2-month period. All subjects were re-examined after another 12-month interval. The examinations at year 4 and 5 included assessment of plaque, gingivitis, probing pocket depth and analysis of samples obtained from the subgingival microbiota at 134 selected sites. The findings from the present study demonstrated: (i) that subgingival scaling and root planing were effective in eliminating subgingival plaque and gingivitis; (ii) that professional therapy resulted in a pronounced reduction of probing depth at sites which at year 4 had a probing depth >3 mm; (iii) that in non-scaled quadrants, the extension of self-performed plaque control resulted in a continued improvement of the periodontal conditions at sites which at year 4 were < 5 mm deep.     

古菌与牙周病的关系

三域分类系统将古菌区别于真核生物和细菌。古菌可生存于极端的生态环境中,如高温、高盐度、高低酸碱度、低氧等环境,也可在普通环境下生长。古菌的细胞结构和分子代谢以及基因转录既不同于原核细胞也不同于真核细胞。用16SrRNA序列研究检测的方法可以检测出人体菌群中无法培养的古菌。牙周病患者口腔中检测出的产甲烷类古菌能加剧牙周组织的破坏,但至今尚未发现致病性的古菌。下面就古菌与牙周病关系的研究进展作一综述。     

Effect of surgical and non-surgical periodontal treatment on periodontal status and subgingival microbiota

The purpose of this study was to evaluate, on a short-term basis, the clinical and microbiological effects of a single course of scaling and root planing as compared with those obtained by flap surgery in patients with moderate to advanced periodontitis. 11 patients participated in the study. Using a split-mouth design, one quadrant of the mouth was treated with reverse bevel flap surgery, whereas the contralateral one was subjected to a single course of scaling and root planing. 2 approximal sites on single-rooted teeth with a pocket depth greater than or equal to 5 mm were monitored clinically and microbiologically for 16 weeks after active treatment. Both techniques resulted in a gain of probable attachment levels, a reduction in bleeding on probing and a reduced mean pocket depth, although 31.2% of the sites in the scaling and root planing group still had 6-7 mm deep pockets at 8 and 16 weeks after treatment. Both techniques reduced median relative proportions and frequencies of detection of black-pigmented Bacteroides species. A highly statistically significant increase (p less than 0.01) in median proportions of oral streptococci was recorded only for surgery within the 1st month post-operatively. No correlation was found between residual pocket depth and any of the microbiological parameters considered in the study, suggesting that residual pocket depth does not exert a significant influence on bacterial subgingival recolonization after therapy. The results from this study suggest that surgery can be as effective as scaling and root planing in favoring the establishment of micro-organisms compatible with periodontal health, although this effect is limited to the 1st month after therapy.     

Clinical, microbiological and immunological features of subjects with refractory periodontal diseases

Abstract 27 subjects with active destructive periodontal diseases were treated by modified Widman flap surgery and systemic tetracycline and divided into 4 groups based on pre- and post-therapy hazard rates (% of sites losing > 3 mm of attachment in 1 year). Pre- and post-therapy hazard rates were respectively: group T (3 subjects) < 4 and < 4; group II (8 subjects) > 4 and < 4; group III (3 subjects) < 4 and > 4; group IV (refractory group of 13 subjects) > 4 and > 4. Baseline mean pocket depths and attachment loss of groups 1 and II subjects were less than groups III and IV subjects and exhibited less suppuration. 6 group IV subjects lost a total of 38 teeth after therapy, in contrast to no tooth loss in subjects in the other 3 groups. Redness, bleeding on probing, plaque levels and age did not differ among groups. Subjects in the 4 groups differed in the subgingival species to which they showed elevated serum antibody responses. Group IV subjects showed elevated responses to a select range of gram-negative species, including A. actinomycetemcomitans strains Y4 or ATCC 29523, F. nucleatum and B. intermedius. No subject in any of the other groups exhibited an elevated response to B. intermedius. The mean % of each species in all sampled sites, both before and after therapy, was computed for each subject. Subjects in groups III and IV (high post-therapy hazard rates) exhibited elevated mean levels of B. forsythus, F. nucleatum, S. intermedius, E. corrodens, and B. gingivalis. Groups I and II subjects showed elevated mean levels of an unnamed Actinomyces species. Refractory subjects (group IV) did not constitute a homogeneous group. While subjects in this group had higher levels of pathogens, it appeared that they differed in the combinations of predominant species. 3 major microbial complexes were observed: (1) B. forsythus, F. nucleatum and W. recta (3 subjects); (2) S. intermedius, B. gingivalis and P. micros (3 subjects); (3) S. intermedius and F nucleatum (7 subjects) with or without B. gingivalis.