Dark-field microscopic monitoring of subgingival bacteria during periodontal therapy

Effects of short-term administration of metronidazole on the subgingival microflora

The effect of a 5-day course of systemic metronidazole was investigated in 11 recall maintenance patients over a period of 3 months. Crevicular fluid flow, bleeding on probing, pocket depth, and composition of the subgingival microbiota as observed by dark-field microscopy, were measured. The study design allowed patients to act as their own controls. At baseline 1 (day 0), each patient had a randomly assigned quadrant scaled and root-planed, and received oral hygiene instruction. Microbiological and clinical parameters were measured at baseline 1 (before treatment) and at 3, 6, and 12 weeks in both the root-planed and a designated no-treatment quadrant. At baseline 2 (12 weeks), the contralateral quadrant was scaled and root-planed, and the oral hygiene instruction was reinforced. At this appointment, each patient was given 15 metronidazole tablets (250 mg), 1 to be taken 3 times per day for 5 days. At the end of this period, patients were seen 1-2 h after taking their last tablet, and blood and crevicular fluid samples were taken to determine the concentration of metronidazole by microbiological assay in the serum and crevicular fluid. Microbiological and clinical parameters were measured at baseline 2 (before treatment) and at 13, 15, 18, and 24 weeks in both the root-planed and designated non-root-planed (metronidazole only) quadrants. Results demonstrated that in this group of recall maintenance patients, metronidazole was no more effective than root-planing alone in reducing the relative % of total motile organisms and spirochetes in 5-8 mm pockets. Crevicular fluid flow was, however, significantly reduced for 11 weeks; serum and crevicular fluid levels of metronidazole were similar 1 to 2 h after drug ingestion.

Phagocytic cells in periodontal defense. Periodontal status of patients with chronic granulomatous disease of childhood

Both qualitative and quantitative neutrophil abnormalities have been associated with severe forms of periodontitis. Defects in chemotaxis, phagocytosis and bacterial killing have been reported among both peripheral blood and gingival neutrophils harvested from patients with juvenile and rapidly progressive periodontitis. Chronic granulomatous disease of childhood (CGD) is a rare, inherited disorder associated with the occurrence of severe, life-threatening, suppurative infections of skin, liver, lymph nodes and other organs. Neutrophils and monocytes from individuals with CGD lack enzymes necessary for the production of oxygen reduction/products such as H2O2 and superoxide anion, and therefore are unable to kill many species of bacteria and fungi. However, no detailed study of the periodontium of these patients has been undertaken. Accordingly, five patients whose ages ranged from 17 to 32 years were included in this study. An additional (sixth) patient was included based on complete dental records. Neutrophils from all patients demonstrated defective O2 metabolism, and all patients had histories of chronic recurrent abscesses consistent with CGD. All patients were receiving antibiotic prophylaxis. Several patients had ulcerative lesions of the oral cavity of unknown etiology. Examination of the periodontium revealed that three patients had gingivitis, one had localized early periodontitis, and one had generalized early-to-moderate periodontitis. The severity of periodontal disease was consistent with patient age and local etiologic factors. No patients had evidence of juvenile, severe or rapidly-progressing disease in spite of their leukocyte defects. These findings suggest the following possibilities.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

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.

Antimicrobial irrigation of deep pockets to supplement oral hygiene instruction and root debridement. I. Bi-weekly irrigation

64 sites with probing pocket depth greater than or equal to 6 mm from 11 patients were treated with plaque control instruction and one episode of root planning. Subsequently, selected sites in each patient were irrigated with either chlorhexidine, tetracycline, saline or served as non-irrigated control sites. Irrigation immediately followed instrumentation, and was repeated every 2 weeks for 24 weeks. Healing was monitored at 8, 16, and 24 weeks clinically and at 7, 15, and 23 weeks with subgingival washings for determination of % as well as total number of spirochetes. The following changes were apparent from comparing pooled site means at 24 weeks with pretreatment data: (1) bleeding sites decreased from 62 of 64 sites initially to 22 of 64 at 24 weeks; (2) spirochetes decreased from 34% to 2%; (3) probing pocket depths decreased from 7.6 to 4.7 mm; (4) probing attachment levels showed a gain of 1.2 mm. The improvement of the chlorhexidine and tetracycline irrigated sites was similar to that of the saline irrigated and non-irrigated control sites. Thus, biweekly chlorhexidine, tetracycline or saline irrigation of deep pockets did not appear to augment the effects of non-surgical periodontal therapy.

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.

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.

Sampling of subgingival microbiota for dark-field microscopy

The aim of the present investigation was to study the validity of 2 different methods of sampling the subgingival microbiota. The composition of the flora was estimated using the dark-field microscope. Subgingival samples were obtained using either a curette or a Hamilton microsyringe for a subgingival washing. The method of determination of the composition of the subgingival microorganisms was found to be very reproducible when the same investigator performed the counting. Samples obtained by the washing technique had a slight but significantly higher proportion of coccoid cells when compared to samples obtained by curette. The calculation of the reproducibility of the washing technique as assessed in 6 immediately repeated samples from the same sites yielded a coefficient of variation of 40% for spirochetes and motile rods. When 9 repeated samples from each of 28 sites (14 with a curette, 14 with washing) were studied over a period of 32 days, no systemic alterations were observed in the % of spirochetes and motile rods. The variation within each individual site was high. For curette samples and washing samples, the coefficients of variation for spirochetes and motile rods were 85% and 63%, respectively. The present investigation clearly demonstrated that care should be taken in the interpretation of single samples of subgingival microbiota. A more relevant picture of the actual situation is achieved when trends of repeated samples over time are studied.

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.

Lactate dehydrogenase activity in gingival crevicular fluid collected with filter paper strips: analysis in subjects with non-inflamed and mildly inflamed gingiva

A previous study of lactate dehydrogenase (LDH) in gingival crevicular fluid (GCF) suggested that the concentration is 10 to 25 times that of serum (means = 2300 international units/1 versus 100 IU/1 for serum). That study used capillary tubes to collect microliter amounts of GCF. Since invasive collection techniques can influence GCF flow, we evaluated LDH activity in GCF collected by filter strips. GCF was collected in a standardized fashion from 10 subjects with mild inflammation (GI = 0.5-1.0) and 10 subjects without evidence of gingival inflammation (GI = 0). Our results indicate that LDH volume activity was greater for subjects with GI = 0 (means = 105,529 IU/1) than for subjects with GI = 0.5-1.0 (means = 77,661 IU/1), but the difference was not significant. LDH total unit activity was significantly greater in subjects with GI = 0.5-1.0 versus GI = 0 (means = 0.048 IU versus means = 0.0242 IU, P less than 0.0001). The relationship of LDH volume activity to GCF volume, the regression lines fit to the data, and calculation of LDH total unit activity were important for analysis of enzyme activity in GCF.

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.

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.

Vancomycin as a selective agent for isolation of Bacteroides species

Thirty saccharolytic and asaccharolytic black-pigmented Bacteroides strains were tested for their susceptibility to vancomycin. All asaccharolytic strains appeared to be partly or completely inhibited at a concentration of 7.5 micrograms/ml, whereas most saccharolytic strains were resistant to this concentration. The use of vancomycin in Bacteroides selective media is discussed.

Microbiological and clinical effects of topical subgingival antimicrobial treatment on human periodontal disease

This study was undertaken to evaluate the microbiological and clinical effects of a subgingivally applied mixture of H2O2-NaCl and NaHCO3 followed by subgingival irrigation with 1% Betadine in the treatment of periodontal disease. 20 adults with moderate to severe periodontal disease were included in a split mouth design study. All patients were given oral hygiene instruction and were subjected to supragingival scaling in all 4 quadrants, and subgingival scaling and root planing of half the dentition. 10 patients were instructed to use the chemical antimicrobial mixture twice a day instead of dentifrice, and also received professional application of the mixture once every 14 days for 3 months in connection with reinstruction in oral hygiene procedures. The remaining 10 patients received oral hygiene instructions combined with professional tooth cleaning without use of chemicals once every 14 days during a 3-month period. The effect of treatment was evaluated by monitoring the subgingival microflora, clinical periodontal parameters, and by computer assisted subtraction analysis of serial standardized radiographs to determine changes in mass of the supporting alveolar bone. The present study revealed that subgingival debridement combined with mechanical plaque control resulted in decreased numbers of subgingival microorganisms including spirochetes and motile rods, and arrested the progressive breakdown of the periodontal tissues. Topical antimicrobial agents used in combination with subgingival scaling further reduced the subgingival microflora and substantially improved early periodontal healing including gain of probing attachment level and gain in radiographic alveolar bone mass during the 12 months of observation. No clinical improvement but a tendency to further periodontal breakdown was found in the unscaled quadrants, even in those which were subjected to a personal application of the topical antimicrobial mixture. This study indicates that professional and personal subgingival application of a mixture of H2O2-NaCl and NaHCo3 will significantly enhance the microbiological and clinical effects of periodontal scaling and root planing. These agents, and the topical mode of antimicrobial therapy seem promising in the management of human periodontal diseases.

A rationale for the management of periodontal diseases: effects of tetracycline on subgingival bacteria

Microbiologic criteria obtained with phase-contrast microscopy were used in a short-term, double-blind study to measure the effects of systemic tetracycline HCl on subgingival bacterial populations in advanced periodontal pockets refractory to local therapy (repeated scaling, root planing, and the subgingival administration of chemotherapeutic agents [H2O2, NaHCO3, NaCl, MgSO4]). Twenty-one subjects, selected for study, had at least one of the following conditions present after local therapy: spirochetes, motile rods, or crevicular leukocytes greater than or equal to 125 per phase-contrast microscopic field. Tetracycline HCl (1 gm/day for 14 days) was randomly distributed to 11 subjects and a placebo to ten subjects, so that neither the subjects nor investigators were aware of the prescription contents. Evaluations after two weeks disclosed that tetracycline HCl significantly reduced elevated levels of spirochetes, motile rods, and crevicular leukocytes to low or undetectable levels, whereas levels in the placebo subjects remained generally unchanged. The results clearly demonstrate the value of tetracycline HCl as an adjunct to periodontal therapy in reducing remaining suspected periodontopathic bacterial populations in advanced lesions after local therapy of scaling, root planing, and topically applied chemotherapy.

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.