New views on periodontal microbiota in special patient categories

A TEM/SEM study of the microbial plaque overlying the necrotic gingival papillae of HIV-seropositive, necrotizing ulcerative periodontitis

The purpose of this study was to examine by transmission (TEM) and scanning electron microscopy (SEM) the supragingival microbial plaque overlying the ulcerated gingival papillae of necrotizing ulcerative periodontitis (NUP) lesions in HIV-seropositive patients. The microbiota of NUP and HIV-seropositive patients with periodontitis has been reported to be similar to that of conventional periodontitis in non-infected subjects, although several investigators have also reported high recovery rates of microbes not generally associated with the indigenous oral microbial flora. Light and electron microscopic observations and microbial culture studies indicate a similar high prevalence of spirochetes in both necrotizing ulcerative gingivitis (NUG) and NUP. In addition, several studies have reported more frequent isolation of Candida albicans from diseased periodontal sites in HIV-seropositive patients than from non-diseased sites. Ten male and six female patients, each HIV-seropositive and exhibiting NUP, constituted the study population. Two biopsies of involved gingival papillae from between posterior teeth were obtained from each patient and processed for examination by both TEM and SEM. Microscopic examination revealed a surface biofilm comprised of a mixed microbial flora of various morphotypes in 81.3% of biopsy specimens. The subsurface flora featured dense aggregations of spirochetes in 87.5% of specimens. Zones of aggregated polymorphonuclear leukocytes and necrotic cells were also noted. Yeasts were observed in 65.6% of specimens and herpes-like viruses in 56.5% of the specimens. Collectively, except for the presence of yeast and viruses, the results suggest that the microbial flora and possibly the soft tissue lesions of NUP and necrotizing ulcerative gingivitis are very similar.

Subgingival microbiota of renal transplant recipients

Renal transplant patients undergoing immunosuppressive therapy may experience periodontal side-effects such as gingival overgrowth. This study evaluated the subgingival microbiota of renal transplant recipients with or without periodontal tissue destruction who may have concurrent gingival enlargement. Subgingival paper point samples taken from the deepest probing sites of 38 subjects (one per patient) were examined using direct microscopy and culture techniques. A complex microflora comprising gram-positive and gram-negative cocci, rods and filaments, fusiforms, curved rods and spirochetes was observed using microscopy. Yeasts were occasionally detected. Significantly higher proportions of gram-positive morphotypes, including gram-positive cocci, were observed in samples from periodontally healthy patients. The predominant cultivable microflora from anaerobic culture comprised several species of facultative and obligate anaerobes. Colonization of the subgingival sites by 'foreign' microbes that are normally dermal, intestinal or vaginal flora was detected in up to 50% of the samples. High mean proportions of lost or unidentified species were also occasionally noted. The results showed that the subgingival biofilm of renal transplant recipients with chronic periodontitis comprised mainly gram-negative rods and spirochetes. Besides the usual predominant cultivable subgingival microbiota associated with periodontitis, the high prevalence of unidentified and 'foreign' microbes indicates the possibility of subgingival microbial alteration in renal transplant patients.

Viability of cultured periodontal pocket epithelium cells and Porphyromonas gingivalis association

OBJECTIVES

Porphyromonas gingivalis, one of the key pathogens in the development of periodontitis, produces a number of virulence factors that might explain its pathogenicity. One of them is the ability to adhere and invade pocket epithelium. The aim of this study was to follow, over time, the association of P. gingivalis and consequent morphological changes of the pocket epithelium cells.

MATERIAL AND METHODS

The association capacity of four P. gingivalis serotypes [K1, K2, K4, K- (nonencapsulated)] with in vitro cultured mono-layers from periodontal pocket epithelial cells of patients with periodontitis, was followed by fluorescence microscopy and bacterial culture. The contact time between bacteria and epithelium cells ranged from 45 min to 8 h. The microscopic evaluation allowed differentiation between dead and living cells (bacteria as well as epithelium) and description of the morphological changes after association.

RESULTS

A highly significant difference in the number of associating bacteria was found between dead and living epithelium cells, and between non-capsulated and capsulated strains. A significant increase in the proportion of dead pocket epithelium cells was found with prolonged association time. The morphological changes (rounding of the epithelial cell, detachment from the glass cover-slip and loss of intercellular contact) occurred faster for mono-layers inoculated with the non-encapsulated P. gingivalis strain.

CONCLUSIONS

This study indicates that dead pocket epithelium cells harbor more P. gingivalis cells, and that a positive correlation exists between contact time and cell death. For the P. ginigvalis species, non-encapsulated strains associate in higher number. As a result, the damage they cause to the host cell seems to occur faster than occurs in encapsulated strains. As such, cell death can be seen as the end-result of bacterial association.

DNA probes and primers in dental practice

In clinical microbiology, molecular genetic techniques are increasingly being used to detect and/or differentiate uncultivable, anaerobic, or fastidious microorganisms. During the past decade, DNA probe hybridization and in vitro amplification by polymerase chain reaction have also been introduced to detect oral pathogens. The present review describes experiences with methods and commercial test systems for the detection of pathogens in periodontitis and caries.

Microbiological findings and host response in patients with peri-implantitis

The aim of the present study was to characterise microbiota and inflammatory host response around implants and teeth in patients with peri-implantitis. We included 17 partly edentulous patients with a total of 98 implants, of which 45 showed marginal bone loss of more than three fixture threads after the first year of loading. Nineteen subjects with stable marginal tissue conditions served as controls. Oral hygiene, gingival inflammation, and probing pocket depth were evaluated clinically at teeth and implants. Microbiological and crevicular fluid samples were collected from five categories of sites: 1) implants with peri-implantitis (PI), 2) stable implants (SI) in patients with both stable and peri-implantitis implants, 3) control implants (CI) in patients with stable implants alone, 4) teeth in patients (TP) and 5) controls (TC). Crevicular fluid from teeth and implants was analysed for elastase activity, lactoferrin and IL-1 beta concentrations. Elastase activity was higher at PI than at CI in controls. Lactoferrin concentration was higher at PI than at SI in patients with peri-implantitis. Higher levels of both lactoferrin and elastase activity were found at PI than at teeth in patients. The concentrations of IL-1 beta were about the same in the various sites. Microbiological DNA-probe analysis revealed a putative periodontal microflora at teeth and implants in patients and controls. Patients with peri-implantitis harboured high levels of periodontal pathogens, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus and Treponema denticola. These findings indicate a site-specific inflammation rather than a patient-associated specific host response.

Infectious risks for oral implants: a review of the literature

The use of oral implants in the rehabilitation of partially and fully edentulous patients is widely accepted even though failures do occur. The chance for implants to integrate can for example be jeopardised by the intra-oral presence of bacteria and concomitant inflammatory reactions. The longevity of osseointegrated implants can be compromised by occlusal overload and/or plaque-induced peri-implantitis, depending on the implant geometry and surface characteristics. Animal studies, cross-sectional and longitudinal observations in man, as well as association studies indicate that peri-implantitis is characterised by a microbiota comparable to that of periodontitis (high proportion of anaerobic Gram-negative rods, motile organisms and spirochetes), but this does not necessarily prove a causal relationship. However, in order to prevent such a bacterial shift, the following measures can be considered: periodontal health in the remaining dentition (to prevent bacterial translocation), the avoidance of deepened peri-implant pockets, and the use of a relatively smooth abutment and implant surface. Finally, periodontitis enhancing factors such as smoking and poor oral hygiene also increase the risk for peri-implantitis. Whether the susceptibility for periodontitis is related to that for peri-implantitis may vary according to the implant type and especially its surface topography.

The intra-oral translocation of periodontopathogens jeopardises the outcome of periodontal therapy

BACKGROUND

Although periodontitis has a multi-factorial aetiology, the success of its therapy mainly focuses on the eradication/reduction of the exogenous/endogenous periodontopathogens. Most of the species colonise several niches within the oral cavity (e.g. the mucosae, the tongue, the saliva, the periodontal pockets and all intra-oral hard surfaces) and even in the oro-pharyngeal area (e.g., the sinus and the tonsils).

METHODS

This review article discusses the intra-oral transmission of periodontopathogens between these niches and analyses clinical studies that support the idea and importance of such an intra-oral translocation.

RESULTS AND CONCLUSIONS

Based on the literature, the oro-pharyngeal area should indeed be considered as a microbiological entity. Because untreated pockets jeopardise the healing of recently instrumented sites, the treatment of periodontitis should involve "a one stage approach" of all pathologic pockets (1-stage full-mouth disinfection) or should at least consider the use of antiseptics during the intervals between consecutive instrumentations, in order to prevent a microbial translocation of periodontopathogens during the healing period. For the same reason, regeneration procedures or the local application of antibiotics should be postponed until a maximal improvement has been obtained in the remaining dentition. This more global approach offers significant additional clinical and microbiological benefits.

Bacterial survival rate on tooth- and interdental brushes in relation to the use of toothpaste

BACKGROUND, AIMS

Previous studies indicated that oral hygiene aids can play a rôle in the intra-oral translocation of pathogens. The survival rate of cariogenic and periodontopathogenic species on toothbrushes, with and without toothpaste, and interdental brushes was presently investigated.

MATERIAL AND METHODS

12 periodontitis patients had their interdental spaces professionally cleaned with interdental brushes and their teeth with new toothbrushes with or without different dentifrices. Each time brushes were rinsed with tap water and stored dry at room temperature. At different time intervals an interdental brush or 4 tufts from a toothbrush were processed for vitality staining and selective and non-selective culturing procedures.

RESULTS

Immediately after rinsing, a toothbrush without toothpaste harboured 10(7), 10(8) and 10(7) colony forming units (CFU) of respectively aerobic, anaerobic and black pigmented species. An insignificant decrease occurred the first 24 hours and after 48 hours still 10(4) CFU of aerobic and anaerobic species could be cultured. No periodontopathogen remained detectable at 8 hours, except for Fusobacterium nucleatum. The proportion of vital bacteria decreased in 48 hours from 50% to 30%. Comparable results were obtained for interdental brushes. The bacterial survival rate on toothbrushes was significantly reduced by the use of a detergent containing toothpaste by 2 log at baseline, another 2 log at 4 hours and an extra log more at 8 hours for aerobic and anaerobic species. A toothpaste without detergent only had an insignificant bactericidal effect.

CONCLUSION

Toothpaste detergents decrease the survival rate of pathogenic species on a toothbrush and can thus limit the risk for bacterial translocation.

One-stage full-mouth disinfection. Long-term microbiological results analyzed by checkerboard DNA-DNA hybridization

BACKGROUND

Recent studies reported significant, additional clinical and microbiological improvements when severe adult periodontitis was treated via the one-stage full-mouth (OSFM) disinfection approach, instead of a standard treatment scheme with staged instrumentation per quadrant. The OSFM disinfection involves dealing with the remaining oropharyngeal niches such as tonsils, saliva, tongue, and mucosa. The OSFM disinfection procedure involves scaling and root planing of all pockets within 24 hours in combination with chlorhexidine application to all oropharyngeal niches (chairside and at home for 2 months). This study aimed to compare the microbiological shifts with the OSFM approach versus standard therapy.

METHODS

Nineteen patients with advanced chronic periodontitis (AP) and 12 patients with early-onset periodontitis (EOP) were randomly assigned to the test and control groups. The control group (9 AP patients, 6 EOP patients) was scaled and root planed, per quadrant, with 2-week intervals. The test group (10 AP patients and 6 EOP patients) underwent OSFM disinfection treatment. At baseline and after 2, 4, and 8 months, pooled subgingival plaque samples were taken from single- and multi-rooted teeth. The presence and levels of 30 subgingival taxa were determined using whole genomic DNA probes and checkerboard DNA-DNA hybridization.

RESULTS

Both treatments resulted in important reductions of the pathogenic species up to 8 months after therapy, both for their detection level and frequency. The OSFM disinfection resulted in an additional improvement, especially in the AP group. P. gingivalis and B. forsythus were reduced below detection level. The number of beneficial species remained nearly unchanged.

CONCLUSIONS

The OSFM disinfection results in supplementary reductions of periodontal pathogens even after 8 months in the treatment of patients with advanced or early-onset periodontitis.

One stage full- versus partial-mouth disinfection in the treatment of chronic adult or generalized early-onset periodontitis. II. Long-term impact on microbial load

BACKGROUND

Recent studies showed the clinical benefits of a one stage full-mouth disinfection, when compared to the worldwide standard treatment strategy of consecutive root planings per quadrant without proper disinfection of the remaining intraoral niches. The purpose of this study was to investigate the microbiological benefits of such a one stage full-mouth disinfection with special attention to all intraoral niches for periodontopathogens and to evaluate the perception by the patients of the new treatment strategy.

METHODS

Sixteen patients with early-onset periodontitis and 24 patients with severe adult periodontitis were randomly assigned to test and control groups. The control group was scaled and root planed, per quadrant, at 2-week intervals and given oral hygiene instructions. The test group received the one stage full-mouth disinfection treatment. At baseline and after 1, 2, 4, and 8 months, microbiological samples were taken from all niches (tongue, mucosa, saliva, and pooled samples from single- and multi-rooted teeth). The samples were cultured on selective and non-selective media. Patient perception of the treatment was evaluated using a questionnaire.

RESULTS

In comparison to the standard therapy, the one stage full-mouth disinfection resulted in significant additional microbial improvements. The test group showed larger reductions in the proportions of spirochetes and motile organisms in the subgingival flora, and more significant reductions in the density of key pathogens, with even the eradication of P. gingivalis. The beneficial effects in the other niches were primarily restricted to the number of colony-forming units/ml of black-pigmented bacteria, especially on the mucosa and in the saliva and to a lesser extent on the tongue. Both treatments were well tolerated by the patients and the overall severity rating for both therapies was comparable, although 4 quadrants were treated within 24 hours in the test group versus only 1 in the control group. The full-mouth disinfection approach resulted more frequently in a slight increase of body temperature, especially after the second day.

CONCLUSIONS

These findings support the benefit of a one stage full-mouth disinfection in the treatment of patients with either chronic adult or early-onset periodontitis.

One stage full- versus partial-mouth disinfection in the treatment of chronic adult or generalized early-onset periodontitis. I. Long-term clinical observations

BACKGROUND

A standard treatment strategy for periodontal infections often consists of 4 consecutive sessions of scaling and root planing (per quadrant, at 1- to 2-week intervals), without proper disinfection of the remaining intra-oral niches for periodontopathogens. This could theoretically lead to a reinfection of previously disinfected pockets by bacteria from an untreated region/niche. This study aimed to investigate, over an 8-month period, the clinical benefits of a one stage full-mouth disinfection in the control of severe periodontitis.

METHODS

Sixteen patients with early-onset periodontitis and 24 patients with severe adult periodontitis were randomly assigned to test and control groups. The control group was scaled and root planed, per quadrant, at 2-week intervals and given standard oral hygiene instructions. A one stage full-mouth disinfection (test group) was sought by scaling and root planing the 4 quadrants within 24 hours in combination with the application of chlorhexidine to all intra-oral niches for periodontopathogens. Besides oral hygiene, the test group also rinsed twice daily with a 0.2% chlorhexidine solution and sprayed the tonsils with a 0.2% chlorhexidine spray, for 2 months. The plaque index, gingival index, probing depth, bleeding on probing, gingival recession, and clinical attachment level were recorded at baseline and at 1, 2, 4, and 8 months afterwards.

RESULTS

The one stage full-mouth disinfection resulted, in comparison to the standard therapy, in a significant (P <0.001) additional probing depth reduction and gain in attachment up to 8 months. For initial pockets > or =7 mm, the "additional" probing depth reduction at the 8 month follow-up was 1.2 mm for single-rooted and 0.9 mm for multi-rooted teeth, with corresponding additional gains in attachment of 1.0 mm and 0.8 mm, respectively. The additional improvements were observed for all subgroups (adult periodontitis, generalized early-onset cases, smokers), with the largest differences in the non-smoking adult periodontitis patients.

CONCLUSIONS

These findings suggest that a one stage full-mouth disinfection results in an improved clinical outcome for the treatment of chronic adult or early-onset periodontitis as compared to scaling and root planing per quadrant at 2-week intervals.

In vitro activities of antimicrobial agents against Candida species

OBJECTIVE

Antimicrobial mouthrinses may represent a valid alternative to topical antifungal agents. However, the action of antimicrobials could be affected by the different ingredients incorporated into mouthrinse products. The purpose of the present study was to investigate the in vitro antifungal and fungicidal activities of antimicrobials alone.

STUDY DESIGN

A broth macrodilution method was used to determine the minimum inhibitory concentration of 4 antimicrobial agents against Candida species. Minimum fungicidal concentration was also determined.

RESULTS

All antimicrobials showed antifungal activity against all tested organisms, but cetylpyridinium chloride received significantly lower minimum inhibitory concentrations (P < .005). Cetylpyridinium chloride also showed a greater fungicidal activity than chlorhexidine digluconate and hexetidine (P< .005), whereas sanguinarine chloride appeared to be less fungicidal against most of the isolates tested.

CONCLUSIONS

These findings suggest that cetylpyridinium chloride may be used as a topical antifungal agent. Clinical trials are now required to assess its value in the management of oral candidosis.

The effect of chemotherapy on the supragingival plaque of pediatric cancer patients

The anaerobic cultivable flora of the dental plaque was investigated in 16 cancer children at days 0, 7, 14 and 21 of a first cure of chemotherapy. Results were compared with those obtained in 16 healthy children. Diseased children showed more quantitative variations of the flora than the controls, especially during the first week of chemotherapy. Whatever the day of sampling, the flora of the diseased children was significantly less complex than that of the controls. Viridans streptococci, Capnocytophaga, and to a lesser extent staphylococci, appeared to be the most strongly affected in diseased children. This could be explained by different mechanisms, uncontrolled recolonization of the dental plaque, selection of multidrug-resistant strains or nosocomial acquisition. These results indicate that variations in quantity, complexity and quality of the oral flora occur during chemotherapy, leading to a major imbalance of the ecosystem.

Awareness of periodontal disease--the role of industry

Recently periodontal treatments have been performed intensively in daily clinical work and the definitive approach to periodontal therapy has been established in various types of periodontal diseases. It is no exaggeration to say that this is impossible without the co-operation of the dental industry. Furthermore, industry has also contributed greatly to the improvement of the 'quality of life', concerning masticatory function in the elderly. Both the progression of dental devices and the development of diagnostic methods have been considered to be the primary prerequisite for success in treatment and in the prevention of recurrence of the periodontal diseases. It is necessary that dental devices and medications for treatment should be developed corresponding to the advanced scientific evaluation of periodontal disease. This paper reviews our present knowledge about the role or contribution of industry to periodontology in terms of periodontal health care products, diagnostic kits, and therapeutic drugs.

Killing of Fusobacterium nucleatum, Porphyromonas gingivalis and Prevotella intermedia by protegrins

Protegrins are broad spectrum antibiotic peptides isolated from porcine leukocytes. In this study, we (i) examine the sensitivity of Gram-negative, anaerobic periodontal pathogens to synthetic protegrins; (ii) determine the relative potencies of protegrin congeners against these bacteria; and (iii) compare the potency of protegrins with other antibiotic peptides, including magainin MSI-78, tachyplesin I, cecropin P1, human defensins HNP-1-3, and clavanin A. Synthetic L- and D-enantiomers of protegrin 1 (PG-1 and D-PG-1, respectively), and L-enantiomers of protegrins 2, 3 and 5 (PG-2, PG-3 and PG-5) were tested against Fusobacterium nucleatum, and black-pigmented organisms including Porphyromonas gingivalis and Prevotella intermedia. Strains of both F. nucleatum and the black-pigmented organisms were sensitive to PG-1, and exhibited mean ED99 of 2.2-2.3 micrograms/ml and 3.4-9.9 micrograms/ml, respectively. The D-form was statistically more potent than the L-form against these oral anaerobes, and although this difference in potency is unlikely to be of decisive therapeutic significance, the D-form may be of value given ability to resist microbial and host-derived proteases. PG-1 was more potent than magainin, tachyplesin, cecropin, defensins and clavanin under test conditions. Hypertonic salt concentrations and heat-inactivated serum were found to be inhibitory to the bactericidal activity of PG-1. PG-1 was found to induce morphologic alterations in the ultrastructural appearance of F. nucleatum consistent with damage to the bacterial membranes. We conclude that protegrins may be useful antimicrobial agents in therapy against Gram-negative anaerobic bacteria believed to be involved in chronic, adult forms of periodontal infections.

The effect of a one-stage full-mouth disinfection on different intra-oral niches. Clinical and microbiological observations

A treatment for periodontal infections often consists of consecutive rootplanings (per quadrant, at a 1- to 2-week interval), without a proper disinfection of the remaining intra-oral niches (untreated pockets, tongue, saliva, mucosa and tonsils). Such an approach, could theoretically lead to a reinfection of previously-treated pockets. The present study aims to examine the effect of a full-mouth disinfection on the microbiota in the above-mentioned niches. Moreover, the clinical benefit of such an approach was investigated. 16 patients with severe periodontitis were randomly allocated to a test and a control group. The patients from the control group were scaled and rootplaned, per quadrant, at 2-week intervals and obtained oral hygiene instructions. The patients from the test group received a full-mouth disinfection consisting of: scaling and rootplaning of all pockets in 2 visits within 24 h, in combination with tongue brushing with 1% chlorhexidine gel for 1 min, mouth rinsing with a 0.2% chlorhexidine solution for 2 min and subgingival irrigation of all pockets (3x in 10 min) with 1% chlorhexidine gel. Besides oral hygiene, the test group rinsed 2x daily with 0.2% chlorhexidine and sprayed the tonsils with a 0.2% chlorhexidine for 2 months. Plaque samples (pockets, tongue, mucosa and saliva) were taken at baseline and after 2 and 4 months, and changes in probing depth, attachment level and bleeding on probing were reported. The full-mouth disinfection resulted in a statistically significant additional reduction/elimination of periodontopathogens, especially in the subgingival pockets, but also in the other niches. These microbiological improvements were reflected in a statistically-significant higher probing depth reduction and attachment gain in the test patients. These findings suggest that a disinfection of all intra-oral niches within a short time span leads to significant clinical and microbiological improvements for up to 4 months.

One-stage Full-mouth Disinfection to Overcome Intra-oral Transmission of Periodontopathogens

The oral cavity offers a range of different niches where periodontopathogens can adhere and survive (e.g. the mucosa, the tongue, the tonsils, the saliva and all intra-oral hard surfaces such as teeth, dentures, oral implants). Transmission of bacteria from one niche to another is likely to occur. Recent studies, for example, illustrated that initially sterile abutments of oral implants were rapidly colonized by bacteria from the subgingival environment around teeth. This transmission of bacteria can occur spontaneously via the saliva, or by means of oral hygiene aids and/or dental instruments. Such an intra-oral transmission, if it occurs at a high speed, could jeopardize the outcome of periodontal therapy. To overcome a bacterial transmission, a 'one-stage full-mouth disinfection' was recently introduced for the treatment of periodontal infections. This new treatment strategy resulted in significant clinical and microbiological improvements when compared with the standard sequential treatment.

Full- versus partial-mouth disinfection in the treatment of periodontal infections. A pilot study: long-term microbiological observations

A standard periodontal treatment consists of 4 to 6 scalings and rootplanings at a 1- to 2-week interval, which allows reinfection of a previously disinfected area before completion of the treatment. The present pilot study aims to examine the microbiological long-term effects of a full-mouth disinfection. 10 patients with advanced chronic periodontitis were randomly allocated to a test and control group. The patients from the control group received scaling and rootplaning and oral hygiene instructions at a 2-week interval. The full-mouth disinfection (test group) consisted of a full-mouth scaling and rootplaning in 2 visits within 24 h in combination with: tongue brushing with 1% chlorhexidine gel for 1 min, mouth rinsing with 0.2% chlorhexidine solution for 2 min and subgingival irrigation of all pockets (3x in 10 min) with 1% chlorhexidine gel. The patients of the test group were instructed to rinse 2x daily with 0.2% chlorhexidine. Plaque samples were taken at baseline and after 1, 2, 4 and 8 months. Differential phase-contrast microscopy showed a significantly larger reduction of spirochetes and motile organisms in the test group up to month 2 for the single-rooted and up to month 8 for the multi-rooted teeth. Furthermore, the culture data supported the effectiveness of the new treatment strategy. In both groups, the number of anaerobic CFU decreased 1 log around single- and 0.5 log around multi-rooted teeth. The number of anaerobic CFU remained low in the test group, in contrast to the control group. At 1 month, the test group harboured a significantly (p<0.01) lower proportion of pathogenic organisms, but this difference disappeared with time. Moreover, the test sites showed a significantly higher (p<0.02) increase in the proportion of beneficial micro-organisms up to 4 months. These findings suggest that a full-mouth disinfection leads to a significant microbiological improvement up to 2 months, which could be consolidated, although not significant, for the next 6 months.

The effect of cyclosporin-A on the oral microflora at gingival sulcus of the ferret

The effect of cyclosporin-A (CyA) on the dentogingival flora of ferrets with healthy and experimentally induced periodontal breakdown was studied. Five animals were given 10 mg/kg/d CyA. At the start of the experiments (day 0), ligatures were placed around 4 teeth in the right upper and lower jaws; corresponding contralateral teeth on the left side served as control. On days 0 and 28 (end of the experiment), microbiological samples were collected from the gingival sulcus of the experimental and the control teeth and from closely located gingival mucosa membrane. The samples were subjected to viable counts and to darkfield microscopic analyses. On day 0, facultative anaerobic rods, mainly Pasteurella spp, Alcaligenes spp, Corynebacterium spp. and Rothia spp dominated in the viable counts. No anaerobic bacteria were detected in the viable counts. On day 28 spirochetes increased in the experimental gingival sulcus samples and anaerobic bacteria appeared in most of the samples and constituted 40-60% of the total cultivable flora; Fusobacterium necrophorum and Eubacterium spp. predominated in the samples from the experimental sites. The results of the present study were compared with those of our previous investigation of ferrets not medicated with cyclosporin but also subject to experimental ligature periodontitis. Eubacterium spp. were absent in the animals not treated with cyclosporin, while this species was frequently present in the immunosuppressed ferrets. The results indicate that the presence of the large numbers of gram negative rods and of anaerobic bacteria may have enhanced the inflammatory process and further provoked the gingival overgrowth observed.

Modifications of the microflora of the oral cavity arising during immunosuppressive chemotherapy

Infections are a major cause of mortality among immunosuppressed cancer patients. The oral cavity is a possible reservoir for those microorganisms, both commensal and acquired, whose virulence is exacerbated in the immunosuppressed patient. The mouth consists of multiple habitats offering ecological niches to a variety of organisms. The object of this article is to review the literature devoted to quantitative and qualitative variations in the flora of the oral cavity during immunosuppressive treatment of cancer patients. Examination of these different studies reveals modifications of the commensal flora, as well as an increase in Gram negative rods, in staphylococci and in yeasts. These data confirm the necessity for constant surveillance of the oral cavity during chemotherapy.

Viability of four putative periodontal pathogens and enteric rods in the anaerobic transport medium VMGA III

The aim of this study was to determine the survival in VMGA III of Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Actinobacillus actinomycetemcomitans and enteric rods in laboratory cultures as well as in subgingival plaque samples. Laboratory strains of the 4 putative periodontal pathogens and Escherichia coli were used in the laboratory part of this study. Also, 31 subgingival plaque samples were obtained from 22 periodontal patients and stored in VMGA III. Each sample, from both the laboratory and the clinical parts, was divided into 3 portions. One portion was cultured within a few hours of collection (baseline), while the second was processed after 24 h (day 2) and the third 48 h later (day 3). The results of the clinical part indicate that the detection frequencies of all 4 periodontal pathogens and their levels in positive samples decreased, to different degrees, by day 2 and decreased further by day 3. Enteric rods were not detected in base line samples. However, they were present in 16.1% and 22.6% of day 2 and day 3 samples, respectively. Similarly, the laboratory results demonstrate a significant decrease in the levels of the 4 periodontal pathogens tested by day 2 and day 3, whereas the opposite occurred for E. coli. P. gingivalis, P. intermedia, and F. nucleatum survived better in the presence of E. coli than alone, whereas A. actinomycetemcomitans survived less well when co-inoculated with E. coli. VMGA III appears to maintain microbial population ratios for periods up to 24 h. After 24 h, the multiplication of enteric organisms may alter the original proportions of the sample.

Some suspected periodontopathogens and serum antibody response in adult long-duration insulin-dependent diabetics

The subgingival microflora and serum antibody response were examined in long-duration insulin-dependent diabetics and age- and sex-matched non-diabetics. The material consisted of 9 diabetics aged 40-49 years and 19 aged 50-59 years, 13 non-diabetics aged 40-49 years and 21 aged 50-59 years. The bacterial species studied (Actinobacillus actinomycetemcomitans, Campylobacter rectus, Capnocytophaga spp, Eikenella corrodens, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia) were recovered in diabetics as well as in non-diabetics. Significantly more diabetics in both age groups harboured P. gingivalis compared to non-diabetics. Prevalence of P. gingivalis was associated with deepened periodontal pockets among non-diabetics but not among diabetics. In diabetics and non-diabetics, the serum antibody titres for most antigens were similar.

Detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Bacteroides forsythus in an A. actinomycetemcomitans-positive patient population

A population of 33 subjects were selected on the basis that all had tested positive for A, actinomycetemcomitans at some time during the prior 7 years. Most subjects (31/33) belonged to families with a proband with confirmed localized juvenile periodontitis (JP); however, most subjects had no evidence of the typical lesions associated with JP. Two additional subjects with rapidly progressive periodontitis, known to be positive for A. actinomycetemcomitans, were also recruited. The patients with a history of JP had been treated, but were no longer enrolled in a regular maintenance program. With 3 exceptions, the subjects had not received any dental treatment or antibiotics in the past 3 months. One aim of the study was to determine the prevalence of A. actinomycetemcomitans, P. gingivalis, and B. forsythus in this population. The main purpose was to compare the relative sensitivity of various methods for detecting these periodontal pathogens. Pooled subgingival plaque samples were collected from all the mesial surfaces and aliquots of the suspension processed for the detection of A. actinomycetemcomitans by culture and indirect immunofluorescence (IF) to serotypes a, b, and c. P. gingivalis and B. forsythus were monitored with a DNA probe and IF. With culture, A. actinomycetemcomitans was detected in 39.4% of the samples, at a mean level of 0.64% of the cultivable counts. With IF, A. actinomycetemcomitans was detected in 81.8% of the samples, at levels of 0.40, 0.79, and 0.17% of the total counts for serotypes a, b and c respectively. Overall, IF was more likely to detect A. actinomycetemcomitans, P. gingivalis, and B. forsythus than any of the other methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Lactoferrin interaction with Actinobacillus actinomycetemcomitans

The interaction of lactoferrin with Actinobacillus actinomycetemcomitans was examined in a 125I-labeled protein binding assay. The binding of human and bovine lactoferrins reached maximum within 1 h. Lactoferrin binding to the bacterium was pH-dependent and reversible. Scatchard analysis indicated the existence of two different types of binding sites on the bacterium, one with a high affinity constant k alpha approximately 8.8 x 10(-7) M) and the other with a low one (k alpha approximately 1.8 x 10(-6) M). Bacteria in the exponential phase of growth showed higher binding than cells in the stationary phase. Bacteria grown in medium containing serum and/or lysed erythrocytes bound lactoferrin to a lesser extent. Heat-inactivated serum, lysed erythrocytes and other proteins such as mucin and laminin inhibited lactoferrin binding to A. actinomycetemcomitans in a competitive binding assay. Sodium dodecyl sulfate polyacrylamide-gel electrophoresis and Western blot analysis of the cell envelope as well as the outer membrane of A. actinomycetemcomitans revealed lactoferrin-reactive protein bands at 29 kDa and 16.5 kDa. The 29-kDa band displayed a heat-modifiable lactoferrin-reactive form with a molecular weight of 34 kDa. Neither proteinase K-treated cell envelope nor lipopolysaccharide of this bacterium showed reactivity with lactoferrin. These data suggests a specific interaction of lactoferrin with outer membrane proteins of A. actinomycetemcomitans.

Comparative detection frequency of 6 putative periodontal pathogens in Sudanese and Norwegian adult periodontitis patients

Twenty-five sudanese and 18 norwegian adult periodontitis patients were selected to participate in this study. The purpose was to compare cultivation results of Porphyromonas gingivalis, Prevotella intermedia, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, and Capnocytophaga species as well as various enteric rods in both populations. In addition, DNA probe analysis was used to identify P. gingivalis, P. intermedia, A. actinomycetemcomitans, F. nucleatum, and Bacteroides forsythus in the Sudanese patients and results were compared with those obtained by cultivation. The paper point technique was used to sample 99 sites in the Sudanese group (4 paper points/site) and 119 sites in the Norwegian patients (3 paper points/site). In the Sudanese subjects, the fourth paper point was used for the DNA probe analysis. The chi-square test and the Wilcoxon signed rank test were used to test for statistically significant differences between Sudanese and Norwegian cultivation results as well as between cultivation and DNA results in the Sudanese group. Cultivation results indicated that the Sudanese subjects had significantly lower prevalence of P. gingivalis, P. intermedia, and F. nucleatum (P < 0.01), significantly higher prevalence of Capnocytophaga species (P < 0.05), and similar prevalence of A. actinomycetemcomitans. Almost all Sudanese subjects tested positive for various enteric rods, while none of the Norwegians did so. The extent to which unrestricted use of antibiotics and transport media influenced the levels of enteric species is not known, however.(ABSTRACT TRUNCATED AT 250 WORDS)

Preventive therapy for periodontal diseases

Rational approaches to the prevention of destructive periodontitis should be based on a clear understanding of etiology and pathogenesis. However, we are dealing with a heterogeneous family of diseases in which different factors operate. It is an oversimplification to regard poor oral hygiene, and hence an accumulation of non-specific dental bacterial plaque, as the major risk factor. Epidemiological evidence indicates that host factors are likely to be of overriding importance for the most severe forms. The limitations of nonspecific plaque control are therefore discussed. Specific inhibitors of virulence factors provide a logical approach, but their clinical application awaits improved knowledge. Improvement of general health and resistance to disease by proper nutrition, the avoidance of intercurrent disease, and elimination of smoking and stress-induced risk are encouraged. The genetic basis of susceptibility to periodontitis is increasingly understood, and, while gene therapy is not likely to be a practicable approach to prevention, genetic markers of risk are emerging.

Clinical and histological evaluation of ligature-induced periodontal breakdown in domestic ferrets immunosuppressed by Cyclosporin-A

The aim of this study was to evaluate, clinically and histologically, the effect of Cyclosporin-A (CyA) on the progression of the periodontal breakdown in the domestic ferret, using the ligature induced periodontitis model. At the start of the experiment (day 0), silk ligatures were placed at the gingival margin level of experimental teeth. The contralateral teeth served as non-ligated control teeth. Clinical measurements included gingival index, probing pocket depth (PPD), probing attachment level (PAL) and gingival overgrowth (GO) and they were performed on days 0, 14 and 28. Cyclosporin-A, 10 mg/kg/d, was given subcutaneously from day 0 to 21, while in the last week there was a reduction of this dose to 5 mg/kg/d. Blood samples were taken on days 0, 14 and 28. On day 28 the animals were sacrificed. Histological sections were prepared for light microscopy. The histometric measurements performed were: (1) the distance between cemento-enamel junction and the alveolar bone crest and (2) loss of connective tissue attachment. The number of sections with root resorption areas was observed. Cell counts were taken in 4 different areas. The results showed, on days 14 and 28, a significant increase of the mean values of PPD and PAL at experimental teeth as compared to the control teeth. GO was present on experimental teeth on days 14 and 28. On day 28, the control teeth presented a very small increase in GO, mainly at the buccal sites of P4 and M1. The histometric results showed a significant loss of attachment and bone resorption in the experimental teeth. Root resorption was found in experimental teeth only. The predominant inflammatory cell in the 4 experimental areas was polymorphonuclears.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of a combination therapy to eliminate Porphyromonas gingivalis in refractory periodontitis

This report describes the clinical and microbiological features of 30 refractory patients and their response to a combined local and systemic therapy at 6 weeks and 3 years following treatment. The refractory treatment protocol (RefTx) consisted of a 2-week regimen of amoxicillin/clavulanate potassium in conjunction with professional, intrasulcular delivery of povidone iodine, and chlorhexide mouthwash rinses b.i.d. Eighty-seven percent of the patients had favorable clinical responses to the RefTx and could be divided into 3 groups (A, B, C) based upon initial flora patterns and the shifts that occurred following treatment. Pretreatment prevalence of Porphyromonas gingivalis (P.g.) was 36.7%. The RefTx was effective in reducing P.g. below detection levels in 10 of the 11 positive patients at P < 0.01; each of these 10 patients (Group A) demonstrated significant gain in attachment. Other black-pigmented Bacteroides species (OBP) were isolated from 70% of the patients at baseline. Nine of these patients did not harbor P.g., showed clinical improvement upon treatment, and were OBP negative following treatment (Group B). Group C patients (7) demonstrated clinical improvement with therapy and did not fit into either Group A or B based upon microbial patterns. Group D patients (4) did not show clinical improvement with 3 patients harboring either P.g. or OBP after treatment. The RefTx was effective at reducing probing pocket depth with a 56% decrease in the number of pockets greater than 6 mm at 6 weeks. This was accompanied by an overall gain of > or = 1 mm of probable attachment in 45% of all sites. The clinical effects of the RefTx were shown to persist at 34.3 months with an apparent attachment gain of > or = 1 mm in 41.2% of sites. These data suggest that P.g. and OBP are important pathogens in refractory periodontitis and that the RefTx protocol is an acceptable, non-invasive alternative for the management of these patients.

Role of suspected periodontopathogens in microbiological monitoring of periodontitis

Periodontal disease is the clinical result of a complex interaction between the host and plaque bacteria. Although a specificity to some degree is found for Actinobacillus actinomycetemcomitans in localized juvenile periodontitis (LJP), it has been difficult to obtain evidence for a specific etiological role of the bacteria associated with periodontal disease in adults. What we see is the net result of host-parasite interactions which in an unpredictable moment accumulate and exceed the threshold of tissue integrity. This hypothesis is concomitant with the view of periodontal disease as a polymicrobial infection, predominantly anaerobic, which occurs commonly in the oral cavity or elsewhere in the body. Some micro-organisms (risk markers) occur more frequently than others and may significantly determine the outcome of this host-parasite interaction. Microbiological sampling and analysis seem to be of limited value in risk assessment; however, they can be used as tools in diagnosis in LJP patients and acute infections, and in treatment decision and therapy control in "refractory" patients. Suspected pathogens (risk markers) are Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and some species of spirochetes, while the roles of Prevotella intermedia, Bacteroidesforsythus, Fusobacterium nucleatum, Campylobacter rectus, and Peptostreptococcus micros are more uncertain. The presence of periodontopathogens as well as enterics, Staphylococcus aureus and Candida especially, should be considered in patients with systemic individual disorders--e.g., diabetes mellitus, neutropenia, agranulocytosis, and AIDS--or with implants.

Identification of Bacteroides forsythus in subgingival plaque from patients with advanced periodontitis

Bacteroides forsythus has been associated with destructive adult periodontitis. Up to now, detailed analysis by classical means was hampered by the fastidious nature of the organism. There is hope that the application of molecular detection methods such as indirect immunofluorescence or in situ hybridization (ISH) will allow for more rapid and accurate identification. Here we describe a B. forsythus-specific probe (BFV530), complementary to 16S rRNA, which correctly identified all B. forsythus isolates as confirmed by biochemical, protein, or fatty acid analysis. To assess whether this probe might be suitable for direct identification of B. forsythus in clinical specimens, a total of 92 subgingival plaque samples were analyzed. Fifty-five specimens were tested in parallel by culture, light microscopy, and filter hybridization. Unfortunately, the overall agreement between results of filter hybridization and conventional methods was 70.9% only. We therefore examined 37 new specimens by ISH and indirect immunofluorescence by using fluorescently labeled probe BFV530 or B. forsythus-specific monoclonal antibody 116BF1.2 (kindly provided by R. Gmür, Zurich, Switzerland), respectively. Agreement between these methods was 100%, indicating that ISH with probe BFV530 might be used to accurately identify B. forsythus directly in subgingival plaque samples.

Black-pigmented gram-negative anaerobes in periodontitis

Black-pigmented Gram-negative anaerobes have been associated with periodontal disease and tooth loss since they were first isolated by Burdon in 1928. Porphyromonas gingivalis, which is usually not isolated from children, adolescents or adults with no periodontal breakdown, has been recognized as one of the most important periodontopathogens. Its presence is strongly correlated with deep periodontal pockets, which are assumed to be its main habitat. Correlations have been shown also with attachment loss, clinical inflammation and serum antibody levels, indicating an aetiological role in the periodontal disease. Their pathogenicity in animal models resembling periodontal disease is documented. They are frequently isolated from periodontal abscesses. The relationship between Prevotella intermedia and periodontal disease is not clear. It is frequently isolated from advanced periodontitis, often as the only black-pigmented Gram-negative anaerobic species; however, the prevalence in adults with no periodontal breakdown is high. It is found frequently in periodontal abscesses and in acute necrotizing and ulcerative gingivitis. Serogroup I is found predominantly in deep periodontal pockets, whereas all serogroups (I-III) are found in shallow pockets and gingivitis. No conclusive difference in pathogenicity between serogroups has been found. Pr. melaninogenica, Pr. denticola and Pr. loescheii are frequently found in the gingival crevice in preschool children and other age groups with gingivitis, but are seldom found in deep periodontal pockets.

Fluorescence in situ hybridization for direct visualization of gram-negative anaerobes in subgingival plaque samples

Fluorescent oligonucleotide probes complementary to variable regions of Porphyromonas gingivalis and Bacteroides forsythus 16S ribosomal RNA were used to identify these organisms in smears of formaldehyde-fixed subgingival plaque samples from patients suffering from periodontitis. Fluorescence in situ hybridization represents a useful method for assessing the microbial ecology of the periodontal flora.

Periodontal microflora of HIV positive subjects with gingivitis or adult periodontitis

The subgingival microflora of 39 HIV+ subjects with gingivitis or adult periodontitis was cultured quantitatively anaerobically for bacteria, spirochetes, and mycoplasma and aerobically for yeasts. Isolates were characterized by conventional biochemical tests, polyacrylamide gel electrophoresis of soluble proteins, cellular fatty acid profiles, immunofluorescence, and immunodiffusion. In general, the same types of bacteria were isolated from the subgingival crevice of HIV+ subjects as we previously had isolated from the subgingival crevice of non-HIV subjects. A statistically significant difference was found between the composition of the flora of HIV+ subjects with adult periodontitis (AP) and concurrent studies of a non-HIV+ AP population. Mycoplasma salivarium was significantly elevated in the HIV+ subjects examined. Yeasts were isolated from only 10% of the samples and from 13% of the HIV-positive subjects at 0.05 to 0.0002% of the total cultivable count when present.

Subgingival microflora of advanced periodontitis in the Dominican Republic

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

Candida biotypes in human adult periodontitis

Fifty-five Candida isolates from human periodontal pockets were biotyped using the API 20C micromethod kit system. Candida albicans (11 biotypes) constituted 81.8% of all yeast isolates. A single biotype accounted for 57.8% of the subgingival C. albicans strains. The biotype distribution of C. albicans in human periodontal pockets appears to follow a selectivity pattern similar to that of other oral surfaces.

Age and sex relationships of superinfecting microorganisms in periodontitis patients

The occurrence by age and sex of subgingival enteric rods and pseudomonads, yeasts, and staphylococci was studied in 3075 "refractory" periodontitis patients referred for microbiological analysis. Each subject contributed a pooled subgingival sample obtained from 3 deep periodontal pockets with paper points. Selective and nonselective media and commercial identification kit systems were used for microbial isolation and speciation. Females constituted about 60% of the study subjects, and almost one-third of all patients were in their forties. Females (47.3%) showed a higher prevalence of the study organisms than males (43.9%). Older females (15.9%) and males (15.3%) revealed significantly higher prevalences of enteric rods and pseudomonads than younger individuals (10.9%), and older infected females yielded significantly higher viable counts than younger infected females. The sexes demonstrated a similar prevalence of staphylococci (about 28%), but younger infected females and males showed significantly higher viable counts than older infected individuals. No sex or age relationships were found for yeasts (about 14% of individuals infected). The high level of subgingival enteric rods and pseudomonads in some individuals may be important in the pathogenesis of geriatric and other forms of periodontitis and may have therapeutic implications.