Relationship between the percentage of subgingival spirochetes and the severity of periodontal disease

Clinical and microbiologic effects of single-dose metronidazole or scaling and root planing in treatment of adult periodontitis

Sites affected with adult periodontitis were observed for 3 months to compare their clinical and microbiologic responses to a single 2 g dose of metronidazole, scaling and root planing, or no treatment. 2 sites with probing depths greater than or equal to 5 mm in each of 18 female subjects (6 in each treatment group) were evaluated clinically (plaque and bleeding indices, probing depth, attachment loss) and microbiologically (%s of cocci, motile rods, non-motile rods and spirochetes, and of obligate anaerobic colony-forming units, black-pigmented Bacteroides, Fusobacterium and Actinobacillus actinomycetemcomitans in subgingival plaque). No significant differences in these variables existed between the 3 groups at baseline. The no-treatment (control) group showed no substantial clinical or microbiologic changes during the study. After 1 month, scaling and root planing had effected significant clinical improvement and significant shifts in the subgingival flora to a pattern more consistent with periodontal health; these changes were still evident at 3 months. In contrast, 1 month after metronidazole, there was some clinical improvement and a significant increase in cocci and a decrease in motile rods, but at 3 months these changes were no longer evident. The results show that the benefits of scaling and root planing are sustained for at least 3 months. However, the benefits of a single 2 g dose of metronidazole are both few and transient, indicating that this regimen, while effective against anaerobic infections in other organ systems, is not clinically or microbiologically effective in the treatment of adult periodontitis.

Adherence of oral treponemes and their effect on morphological damage and detachment of epithelial cells in vitro

The present study shows adherence of Treponema denticola L12D and Treponema vincentii RitzA to guinea pig ear epithelial cells in vitro. The number of adhering organisms was positively related with the treponemal concentration and contact time. Incubation of washed T. denticola L12D and T. vincentii RitzA organisms or their culture supernatants with the epithelial cells induced morphological damage and detachment of these cells. In addition, indications for inhibition of epithelial cell proliferation were found. The activity of the supernatants was dose dependent, heat sensitive, and sensitive to sulfhydryl-containing components, suggesting the presence of enzymatic activity that might be of importance in the pathogenicity of these oral treponemes.

A 7-month study of sulcular fluid flow in the assessment of healing after debridement of deep pockets

The purpose of this investigation was to assess the value of sulcular fluid flow (SFF) measurements in evaluation of the healing of deep periodontal pockets after scaling and root planing. Fourteen adult patients with advanced periodontal disease received supragingival prophylaxis and instructions in oral hygiene. Immediately after baseline examination, meticulous scaling and root planing were performed. One to five selected pockets per patient were monitored on Days 0, 30, 120 and 210. Subgingival microbial proportions, sulcular fluid flow, probing depth, Gingival Index and bleeding after probing were assessed and recorded. The subgingival microbial proportions were determined with darkfield microscopy. The periodontal conditions were markedly improved by Day 210 as depicted by the microbial proportions. The proportion of motile micro-organisms was reduced from 51% at baseline to 9% on Day 30. This result was sustained until Day 210. Healing was also evident from the changes in Gingival Index scores and bleeding after probing. Probing depth was reduced from a mean of 8.3 to 4.5 mm. Correlations between the individual means recorded for the clinical parameters and bacterial proportions were calculated for the pooled data of all four examinations. Sulcular fluid flow did not correlate with the clinical parameters. Gingival Index, bleeding after probing or probing depth. The latter three parameters correlated significantly with the microbial proportions and each other. When the pooled tooth surface recordings of Days 30, 120 and 210 were divided into two groups according to the proportion of motile bacteria (the groups with less than 18% of spirochetes and motile rods and the groups with greater than 18% of spirochetes and motile rods), a significant difference in the mean amount of sulcular fluid flow (P less than 0.01) and mean probing depth (P less than 0.001) could be demonstrated between the two groups.

The microbial morphotypes associated with periodontal health and adult periodontitis: composition and distribution

Subgingival plaque samples were obtained from 162 sites in 27 adult periodontitis patients and 162 sites in 27 healthy patients using a standardized lavage technique. The distribution of 10 different microbial morphotypes was determined by darkfield microscopy. The lavage technique selectively samples the loosely adherent plaque at the base of the periodontal pocket and not the tooth-associated, adherent plaque. This standardized technique permits quantitative comparisons of numerical density of morphotype composition at different sites, in addition to qualitative comparisons or relative proportions. There was a significant positive association between the numerical density of each morphotype within the non-adherent plaque and the number of sites at which the organism was detected in both healthy and diseased subjects. A previously undescribed darkfield morphotype, has been detected with this method. This morphotype, a small motile coccobacillus (S-MO-CB) has been found to be the numerically dominant species in both health and disease. This morphotype has been recovered in pure culture following passage through a 0.4 mu filter and includes organisms of the Wollinella and Campylobacter genus. Non-motile organisms comprised less than 1-2% of the sample from healthy and diseased sites. Motile forms, such as spirochetes, had a high frequency of detection in healthy individuals. Analysis of pooled plaque samples revealed that the prevalence of cocci and fusiforms was significantly elevated in patients with healthy periodontium, as compared to patients with adult periodontitis. In adult periodontitis patients, the frequency of occurrence of medium spirochetes, filaments and small nonmotile rods was significantly elevated in pooled plaque. Analysis of individual sites indicated that the proportion and numerical density of most morphotypes within the non-adherent plaque were not significantly different in disease as compared to health. Disease is characterized by an increased % of small spirochetes and fusiforms at each site. At diseased sites which harbor small spirochetes, the numerical density is elevated four-fold, as compared to healthy sites which have small spirochetes. The numerical density of other morphotypes is not significantly different comparing healthy sites to diseased sites. Thus, the increase in the % of small spirochetes in disease in due to a site-localized four-fold increase in numerical density within the non-adherent plaque.

Antimicrobial irrigation of deep pockets to supplement non-surgical periodontal therapy. II. Daily irrigation

106 sites with probing pocket depths 7 mm or greater from 14 patients were treated with plaque control instruction and 1 episode of root planing. Sites in each patient were either irrigated with 2% chlorhexidine or left as non-irrigated controls. Irrigation immediately followed root planing and was repeated daily, by the patient, for 24 weeks. Clinical measurements were made at 12 and 24 weeks, as were gingival washings for determining the number and % of spirochetes. Results at 24 weeks demonstrated that bleeding scores decreased from 91% to 9%; the % of spirochetes dropped from approximately 9% to less than 1%; probing pocket depths decreased from 7.5 to 4.5 mm, and probing attachment levels gained 1.1 to 1.4 mm. The chlorhexidine irrigated experimental group and the non-irrigated control group did not differ significantly in any of the studied parameters. Thus, daily patient-administered chlorhexidine irrigation of deep pockets did not augment the effects of non-surgical periodontal therapy.

Pericoronitis: a reappraisal of its clinical and microbiologic aspects

Pericoronitis is an infectious disease of the operculum overlying an erupting or semi-impacted tooth. It manifests itself mainly in late adolescence and young adulthood and nearly always occurs around the lower third molar. The distinctive location, age, clinical picture, and link with predisposing factors warranted a reappraisal of pericoronitis and its etiology. Spirochetes and fusobacteria proved prevalent at all stages of the disease. The presence of these microbacteria may provide a clue as to the late appearance, particular location, and singular clinical picture of pericoronitis. The fact that spirochetes and fusobacteria are also found in acute necrotizing ulcerative gingivitis, and have been associated with alveolar osteitis, indicates a possible relationship between these disorders and pericoronitis.

Effect of self-administered daily irrigation with 0.02% SnF2 on periodontal disease activity

To determine the effect on periodontal health of a daily self-administered irrigation with 0.02% stannous fluoride (SnF2) solution, 28 subjects who had moderate to advanced periodontitis were randomly divided into 3 groups: a control group (n = 9) which used no irrigation, a group (n = 8) which used a self-administered water irrigation device (Water Pik) daily with water (H2O group) and a group (n = 11) which used the Water Pik in a similar manner but with SnF2 solution (SnF2 group). All subjects were instructed in routine tooth brushing and flossing but received no other periodontal treatment. 4 study sites were selected from each patient which had pocket depths greater than 4 mm and bleeding upon probing. Plaque index, gingival index, bleeding tendency, pocket depth, loss of attachment, and microbiologic samples of subgingival plaque for morphologic determinations were collected from all study sites at baseline, 2, 6, and 10 weeks. A cross-over was then initiated for 2 additional monthly checks in which the H2O group changed to SnF2 and the SnF2 group was divided into 2 subgroups which either continued to use SnF2 or changed to H2O. The control group completed the study at the beginning of the crossover. The clinical data showed significantly more improvement in periodontal health during the first 10 weeks for the SnF2 group (p less than 0.01). After cross-over, the clinical data indicated the group that changed from H2O to SnF2 significantly improved their periodontal health, while the group that changed from SnF2 to H2O became worse. The microbiologic data showed trends which agreed with the clinical data during the first 10 weeks but were less significant. After cross-over, the %s of motile rods and spirochetes were too small (0-7%) to establish statistically significant changes considering the accuracy of the technique used.

The similarity of periodontal microorganisms between husband and wife cohabitants. Association or transmission?

Fourteen married couples were studied to determine the degree of similarity of the periodontal subgingival flora between paired contralateral sites and between couples. Six sites per person were sampled by a subgingival lavage technique and 10 darkfield morphotypes enumerated at each site. Cross-arch matching revealed a positive association for the presence of medium spirochetes, filaments, large motile rods and cocci (P less than 0.05). The odds that medium spirochetes will be detected at a subgingival site are elevated 7-fold, if present at the contralateral site. Similarly, the odds ratio for filaments was 4.0, 1.3 for large motile rods and 1.6 for cocci. Analysis of data, pairing between couples, revealed a positive association for medium spirochetes and filaments (P less than 0.05). No significant associations were found for randomized pairs of couples using matched sites as controls. The odds of medium spirochetes being present in a patient are 3 times greater if the morphotype is present in the spouse and 30% greater for filaments. Although an individual is "at risk" if these morphotypes are present in the spouse, analyses failed to demonstrate that the presence of any morphotype depends upon, or requires the presence of, that morphotype in the spouse.

Microbial interpretation of plaque relative to the diagnosis and treatment of periodontal disease

It has been suggested that monitoring microbial forms in plaque with the microscope may prove useful to the clinician in assessing periodontal status. In this regard, the microbial interpretation of plaque relative to the diagnosis and treatment of periodontal disease has recently received considerable attention. However, questions remain to be answered before the microscope is accepted for routine use in the diagnosis and treatment of periodontal disease. This report addresses a number of these questions surrounding the use of the microscope in evaluating plaque and its role in the diagnosis and treatment of periodontal disease.

Effects of scaling and root planing on subgingival microbial proportions standardized in terms of their naturally occurring distribution

This investigation included a cross-sectional component (284, 20-40-year-old subjects/568 sites) and a longitudinal component (19 subjects with moderate to advanced periodontitis/76 sites). Subgingival plaque samples and clinical data were obtained from all upper second bicuspids and first molars in the longitudinal subjects and from both upper first molars in the cross-sectional subjects. The purpose was to: determine/confirm changes in proportions of selected subgingival microorganisms following root planning combined with conventional oral hygiene procedures in the longitudinal subjects, evaluate those changes in terms of an estimate of the naturally occurring distribution of subgingival microorganisms based on data obtained from the cross-sectional subjects and relate shifts in the subgingival microorganisms to changes in clinical measurements. Changes following treatment at sites with pre-instrumentation probing depths greater than or equal to 4.5 mm included cocci, 18.3 to 46.9%; spirochetes, 20.9 to 3.1%; total motile organisms, 28.5 to 5.9%; Fusobacterium spp., 10.2 to 2.2%; and dark-pigmented Bacteroides spp., 14.0 to 9.7%. Translating proportions of microorganisms in samples from subjects in the longitudinal treatment study to equivalent percentile ranks within the large cross-sectional data base demonstrated that at probing depths greater than or equal to 4.5 mm cocci moved from below the 50th percentile in our estimate of the naturally occurring distribution of subgingival microorganisms to above, and spirochetes, total motile organisms and Fusobacterium spp. moved from above the 50th percentile to below. The microbiological findings were consistent with statistically significant improvements in clinical measurements. Statistically significant changes also occurred in microorganisms at sites with initial probing depths less than 4.5 mm.

3-year longitudinal study of the periodontal status of an adult population with gingivitis

69 adults ranging in age from 20 to 73 (mean age: 37) were randomly assigned to a control (C) and a test (T) group. Of these, 61 completed the 3-year longitudinal study. All subjects had varying degrees of gingivitis at the start, but no overt periodontitis. Following a base line examination for P1I, GI, probing depth (PD) and recession, a differential darkfield microscopic (DDFM) count of subgingival bacterial morphotypes was carried out on a pooled sample originating from one tooth surface in each sextant with the greatest probing depth. Examinations were repeated every 6 months for 3 years. The C group received regular prophylaxes every 6 months. The T subjects received prophylaxes according to a previously described schedule, and on the basis of the DDFM test outcome. Recall intervals at the end of the study for the T group ranged from 1 to 24 months (mean: 15.7 months). Of 30 subjects in the T group at the end of the study, one half had not had their teeth cleaned for periods of 18 to 36 months without any detectable deterioration in their periodontal status by comparison with the other T subjects or the patients in the C group. Both C and T subjects exhibited increased mean P1I and GI scores as compared to base line during the first half of the study. However, mean PD measurements remained unchanged. Increases in PD from base line of 3 mm or more were observed only in approximately 1 out of a 1000 individual tooth surface comparisons, a frequency comparable to that expected to occur by chance alone. This observation indicates that in this population, little if any pocket formation occurred during the study period. GI score increases of 2 units or more occurred in relatively few subjects. 2 of 31 C patients accounted for 42% of the affected dental units, while 5 out of 30 T subjects accounted for 40.8% of the affected dental units in that group. These observations suggest that despite the relatively high prevalence and incidence of gingivitis, the subjects were relatively resistant to periodontitis. Neither preventive schedule was effective in eliminating gingivitis. The lack of significant destructive disease in this population prevented any meaningful comparison of the relative effectiveness of the two preventive maintenance regimens in preventing recurrences of periodontitis.

The role of bleeding upon probing in the diagnosis of periodontal disease. A literature review

Assessment of bleeding upon probing is an integral part of a periodontal examination. Recent investigations have indicated that bleeding reflects histological, clinical and bacteriological alterations associated with periodontal disease. Furthermore, clinical and histologic data suggest that bleeding is an earlier sign of gingivitis than visual signs of inflammation (redness and swelling). The current literature referring to the role of bleeding upon probing in the diagnosis of periodontal disease is reviewed, and its limitations as a clinical parameter are discussed.

Clinical assessment of injuries in orthodontic movement of impacted teeth. II. Surgical recommendations

Adverse effects on periodontal tissues have been associated with surgical techniques used to expose impacted teeth that are to undergo orthodontic tooth movement. The purpose of this study was to compare the effects on the periodontium of two of the more commonly used surgical techniques for labially impacted canines--(1) exposure of the entire labial aspect of the anatomic crown with total excision of all keratinized tissue (the window approach) and (2) a technique which exposes only 4 to 5 mm of the most superficial portion of the labial aspect of the cusp tip while maintaining 2 to 3 mm of keratinized tissue. Twelve patients were selected who had undergone comprehensive orthodontic therapy for a unilateral labial impaction of an upper canine, and who had the impacted canine surgically exposed with a window approach. This group's periodontal status after orthodontic therapy was compared to that of another group of twelve patients who had also undergone comprehensive orthodontic therapy for a unilaterally impacted labial upper canine but in whom the surgical exposure of the impacted tooth had been performed in a manner which preserved 2 to 3 mm of keratinized tissue on the labial aspect. The results indicated that the twelve subjects in whom the window approach had been used had statistically more gingival recession, gingival inflammation, and loss of attachment on the labial and labioproximal surfaces of the impacted teeth than the other group that had 2 to 3 mm keratinized tissue maintained after surgical exposure (p less than 0.05).

Bactericidal action of bicarbonate ion on selected periodontal pathogenic microorganisms

Organisms representative of soil, skin and fecal flora and of supragingival and subgingival flora were tested for inhibition of growth and killing by various salts (NaHCO3, NaCl, MgSO4). The antimicrobial activities of KHCO3, NaF, sodium lauryl sulfate (SLS) and chloramine T were also compared with that of NaHCO3, and the rate at which NaHCO3 exerts its bactericidal effect was studied. Suspected periodontal pathogens were more susceptible to salts than were control non-oral bacteria. Supragingival plaque organisms showed intermediate susceptibility. Periodontal pathogens were more susceptible to NaHCO3 than to NaCl; NaHCO3 and KHCO3 showed similar activity against all strains tested. Accordingly, the antibacterial activity of NaHCO3 is not simply an osmotic effect and is due to the bicarbonate ion. NaF, SLS and chloramine T had greater antimicrobial activity than NaHCO3. Supragingival bacteria required at least 6-hour exposure to 1.0 M NaHCO3 to produce 99% lethality (decrease colony-forming units by 2 log10), whereas selected periodontal pathogens were killed more rapidly (30-120 minutes). The higher the concentration of bicarbonate, the faster the lethality. Morphologic examination by transmission electron microscopy of organisms exposed to bactericidal salt concentrations revealed marked fibrillar condensations within the cytoplasm and shrinkage of the cytoplasm from the outer membrane. For NaHCO3 to be clinically effective, a high concentration must be introduced into the periodontal pocket and maintained there long enough to kill periodontal pathogens. Furthermore, NaHCO3 must be reapplied often enough to prevent recolonization by these pathogens. An advantage of NaHCO3 over NaF, SLS and other antimicrobial agents is its safety, availability and low cost.

Cultivation on solid media of spirochetes in subgingival plaque from advanced marginal periodontitis in humans

Six solid substrates were compared for suitability to support growth of spirochetes from 18 subgingival plaque samples in patients with advanced marginal periodontitis. The following substrates with rabbit serum were tested: BHIA-SC + blood, RGCA-SC + blood, GM-1 +/- blood and MGM-1 +/- blood. All media contained rifampicin and polymyxin B. After incubation in a glovebox (70% N2, 20% H2, 10% CO2) for 14 days spirochete colonies were semiquantitated and the colony morphologies described. The spirochetes in six of the primary samples and in the related colonies after cultivation were identified ultrastructurally by number of endoflagella. The results showed that the colony morphologies were more related to the substrate used than to the various types of spirochetes, and that individual colonies contained different types of spirochetes. The substrates MGM-1, RGCA-SC, and BHIA-SC, all with blood, showed the highest recoveries of about 5%. Spirochetes with less than four endoflagella grew on all substrates, but the MGM-1 + blood and RGCA-SC + blood media seemed the most versatile as they showed growth of all types of spirochetes observed in the primary samples.

Simple bacteriological methods to assess changes in subgingival microflora produced by metronidazole-containing acrylic strips placed into periodontal pockets

Dark field microscopy is perhaps the simplest microbiological technique to monitor the effects of treatment methods on bacterial plaque. However, the method provides qualitative rather than true quantitative data. This study attempts to measure changes in flora by a number of methods following the placement of 40% metronidazole acrylic strips into periodontal pockets. 10 patients with periodontal pockets greater than 6 mm which bled on probing had acrylic strips placed for 2 to 3 days. Prior to insertion and after removal, subgingival plaque samples were collected into 1 ml of saline and processed as follows. (a) Dark field microscopy for qualitative shifts. (b) Gram stain for differential counts. (c) Counting chamber for total counts. (d) Serial dilution and culture for total cultivable counts. After treatment the significant changes were as follows. (a) % increase in cocci and decreases in other forms, particularly motile organisms. (b) Gram-positive cocci increased and Gram-negative bacilli decreased. (c) Total counts obtained by the sampling method decreased greater than 80%. (d) Total cultivable counts decreased greater than 75%. (e) The efficiency of culturing appeared low and the potential problems of sampling to quantification were identified. The consistency of the changes produced suggested that using simple bacteriological techniques it was possible to show marked changes in the numbers and types of organism present in subgingival plaque following the use of local antimicrobial therapy.

Pectinolytic enzymes of oral spirochetes from humans

Five strains of obligately anaerobic, pectin-fermenting spirochetes were isolated from the subgingival plaque of humans. The strains produced two extracellular enzymatic activities that functioned in pectin degradation. One of these enzymatic activities was pectin methylesterase (EC 3.1.1.11), and the other was pectate lyase (EC 4.2.2.2) of the endo type. The data indicate that the cumulative action of these two enzymatic activities brought about depolymerization of pectin in spirochete cultures. Pectin- or polygalacturonate-degrading hydrolases were not detected. A cell-associated lyase activity that catalyzed polygalacturonate breakdown was present in one of the spirochete strains. In addition to pectin, the isolates utilized polygalacturonic, glucuronic, or galacturonic acid as fermentable substrate but did not neutral sugars, amino acids, or other substrates tested. Although the oral spirochetes did not ferment hyaluronic acid, one of the strains grew in coculture with a hyaluronidase-producing Peptostreptococcus strain in a medium containing hyaluronic acid as fermentable substrate. Two of the isolates were identified as Treponema pectinovorum strains on the basis of their substrate utilization pattern, end products of fermentation, other phenotypic characteristics, and the guanine-plus-cytosine content of their DNA. Even though the pectinolytic isolates were specialized with respect to the fermentable substrates they utilized, they appeared to compete successfully with other microorganisms in their habitat.

Comparison of the immediate effects on the sub-gingival microflora of acrylic strips containing 40% chlorhexidine, metronidazole or tetracycline

In the management of chronic periodontitis, there has been a renewed interest in the local delivery of antimicrobial drugs into periodontal pockets. This study assessed the effects of the acrylic strip delivery system containing chlorhexidine, metronidazole or tetracycline on subgingival microflora assessed by dark field microscopy. Strips containing 40% chlorhexidine, metronidazole or tetracycline were placed for 2 to 3 days into pockets greater than 6 mm which bled on probing. Plaque samples were obtained before and after treatment and counts of morphological and motile groups of organisms were made by dark field microscopy. Prior to treatment, the dark field microscopic counts were similar to those previously reported for diseased sites with motile bacteria, in particular spirochaetes, present in high numbers. Following treatment, all 3 antimicrobial drugs produced a significant increase in the proportion of cocci and significant decreases in all other types of organisms. Motile organisms, in particular, were markedly reduced and spirochaetes could not be recovered from some sites treated with metronidazole and tetracycline. Metronidazole was significantly more effective than tetracycline or chlorhexidine on spirochaetes. The results indicate that acrylic strips may be useful in the management of chronic periodontitis as an adjunct to routine mechanical methods.

Recolonization of a subgingival microbiota following scaling in deep pockets

The present investigation was carried out to study some aspects of the recolonization of a subgingival microbiota following subgingival instrumentation in sites with deep pockets. 16 patients were recruited for the study. From each patient 4 inflamed gingival sites with deep pockets were selected. These sites were examined for plaque, overt gingivitis, bleeding on probing and probing depth. Samples of the subgingival microbiota were obtained and examined in the darkfield microscope and in a Neubauer chamber. Following the Baseline examination the teeth of all 4 jaw quadrants were carefully scaled and planed. Subgingival instrumentation was carried out under local anesthesia and required between 2-4 appointments. The patients were subsequently divided into 2 groups (Groups A and B) consisting of 9 and 7 subjects, respectively. During the first 16 weeks of maintenance the patients of Group A were not supervised regarding their self-performed plaque control measures and they accumulated supragingival plaque. The patients of Group B, however, were during these 16 weeks recalled once every 2 weeks for professional tooth cleaning. In addition they rinsed twice daily with a 0.2% solution of chlorhexidine digluconate. Reexaminations including assessments of the same parameters as those studied at Baseline were performed after 2, 4, 8, 12 and 16 weeks. After the 16-week examination the patients of Group A received a new sequence of subgingival scaling and root planing. During the subsequent 16 weeks the patients of Group A were also recalled for professional tooth cleaning. They were reexamined 18, 20, 24, 28 and 32 weeks after the Baseline examination. Subgingival scaling followed by carefully supervised oral hygiene measures resulted in a marked improvement of periodontal conditions. This improvement was accompanied by a pronounced and sustained reduction in the motile segments of the subgingival microbiota. In the presence of supragingival plaque (Group A), however, a subgingival microbiota containing large numbers of spirochetes and motile rods was soon (4-8 weeks) reestablished. A small number of sites with deep pockets (greater than or equal to 8 mm) was not substantially reduced in depth following subgingival instrumentation. In these sites which were kept free from supragingival deposits a subgingival microbiota with a large proportion of motile bacteria soon recurred.

Attachment of Treponema denticola to cultured human epithelial cells

The present electron microscopic study visualizes adherence of Treponema denticola, the most common treponeme of the gingival crevice in man, to human epithelial cells in vitro. The number of organisms adhering to the cells increased with increase in the treponemal concentration from 10(6) cells/ml through 10(8) cells/ml. Epithelial cells immediately after mitosis were particularly rich in treponemes. The number of adsorbing treponemes was reduced after pretreatment of the epithelial cells with hyaluronidase. The epithelial cells showed no predilection site of treponemal attachment. Treponemes attached preferably by their ends. Intracellularity of treponemes was not regularly attained. Treatment with ruthenium red, acidic bovine albumin or hyaluronidase indicted presence of acidic mucopolysaccharides on the treponemal and epithelial cell surface.

The effect of supragingival plaque removal on anaerobic bacteria deep periodontal pockets

A study was made to determine if the numbers of subgingival anaerobes in deep periodontal pockets can be controlled by removal of only supragingival plaque. The study was based on the premises that the subgingival flora is dependent on the supragingival plaque for its source of organisms as well as for its perpetuation. Daily professional removal of only supragingival plaque produced a statistically significant reduction per sample in subgingival facultative and obligatory anaerobes.

Effects of nonsurgical periodontal therapy on periodontitis in humans. A review

Root planing is an effective method of treating both moderate and severe periodontitis. Predictable and significant improvement in bleeding scores, probing pocket depths and probing attachment levels have been demonstrated by a number of different research groups. Significant positive changes in the subgingival microflora are induced. These improvements can be sustained for longer periods of time if adequate supragingival plaque control is achieved. It is important to realize that the research to date excludes the effects of therapy on furcation pockets. Results of conservative therapy in this critical area remain to be studied.

A rationale for management of periodontal diseases: rapid identification of microbial 'therapeutic targets' with phase-contrast microscopy

Monitoring the composition of subgingival flora can provide clinicians with a supplement to periodontal diagnosis and therapy. Conventional bacteriologic culturing may be clinically impractical, but direct microscopy may not.