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

Antimicrobial Chemotherapy for Recalcitrant Severe Human Periodontitis

This study evaluated a combined systemic and topical anti-infective periodontal treatment of 35 adults who had experienced ongoing periodontal breakdown following conventional surgical periodontics. The prescribed anti-infective therapy, based on microbiological testing, consisted of a single course of metronidazole plus ciprofloxacin (23 patients), metronidazole plus amoxicillin/clavulanic acid (10 patients), and metronidazole plus ciprofloxacin followed by metronidazole plus amoxicillin/clavulanic acid (2 patients). In addition, the study patients received 0.1% povidone-iodine subgingival disinfection during non-surgical root debridement and daily patient administered oral irrigation with 0.1% sodium hypochlorite. At 1 and 5 years post-treatment, all study patients showed gains in clinical periodontal attachment with no further attachment loss, and significant decreases in pocket probing depth, bleeding on probing, and subgingival temperature. The greatest disease resolution occurred in patients who at baseline harbored predominantly major periodontal pathogens which post-antibiotics became non-detectable and substituted by non-periodontopathic viridans streptococci. The personalized and minimally invasive anti-infective treatment regimen described here controlled periodontitis disease activity and markedly improved the clinical and microbiological status of the refractory periodontitis patients.

Structural and Genetic Diversity of Entamoeba gingivalis Trophozoites Isolated from Diseased and Healthy Periodontal Sites

BACKGROUND: At present, there is little documented about the variability aspects of Entamoeba gingivalis (E. gingivalis) in relation to periodontal diseases. This is perhaps due to several specialists rejecting the notion that E. gingivalis can cause periodontal disease. AIM: The aim of the present study was to compare the morphological and genetic variability within trophozoites isolated from diseased (n = 26) and healthy periodontal sites (n = 14). METHODS: Detailed microscopic analyses were performed, in addition to post real-time polymerase chain reaction 18S-SSU rRNA gene scanning technology, using reference synthetic genes to analyze melting curve features from different isolates. RESULTS: All trophozoites isolated from diseased sites were significantly larger in size than those isolated from healthy sites. In addition, they were found in clusters, containing many leukophagocytosis and in a significantly higher number than those from healthy sites. Gene scanning revealed diversity within the isolates with a significantly higher number of mutant forms (18 out of 26) within the trophozoites isolated from diseased sites, 14 of them were of unknown origin. Four melting curves matched E. gingivalis H57 strain and the remaining eight were related to the wild strain (ATCC-30927). Isolates from healthy sites corresponded to the wild type (12 out of 14) with only two related to H57 strain. CONCLUSION: The study confirmed morphological and genetic variability between different isolates; We still recommend further in-depth molecular studies to investigate the role of this oral protozoan in the pathogenicity of periodontal affection. The study highlighted the importance of real engagement of multidisciplinary diagnostic strategies, involving experts from variable medical fields to reach truthful scientific outcomes concerning the association of certain microorganism to particular diseases or disorders.

Reassessing the Role of Entamoeba gingivalis in Periodontitis

The protozoan Entamoeba gingivalis resides in the oral cavity and is frequently observed in the periodontal pockets of humans and pets. This species of Entamoeba is closely related to the human pathogen Entamoeba histolytica, the agent of amoebiasis. Although E. gingivalis is highly enriched in people with periodontitis (a disease in which inflammation and bone loss correlate with changes in the microbial flora), the potential role of this protozoan in oral infectious diseases is not known. Periodontitis affects half the adult population in the world, eventually leads to edentulism, and has been linked to other pathologies, like diabetes and cardiovascular diseases. As aging is a risk factor for the disorder, it is considered an inevitable physiological process, even though it can be prevented and cured. However, the impact of periodontitis on the patient's health and quality of life, as well as its economic burden, are underestimated. Commonly accepted models explain the progression from health to gingivitis and then periodontitis by a gradual change in the identity and proportion of bacterial microorganisms in the gingival crevices. Though not pathognomonic, inflammation is always present in periodontitis. The recruitment of leukocytes to inflamed gums and their passage to the periodontal pocket lumen are speculated to fuel both tissue destruction and the development of the flora. The individual contribution to the disease of each bacterial species is difficult to establish and the eventual role of protozoa in the fate of this disease has been ignored. Following recent scientific findings, we discuss the relevance of these data and propose that the status of E. gingivalis be reconsidered as a potential pathogen contributing to periodontitis.

Introduction to Clinical Microbiology for the General Dentist

Clinical oral microbiology may help dental professionals identify infecting pathogenic species and evaluate their in vitro antimicrobial susceptibility. Saliva, dental plaque biofilms, mucosal smears, abscess aspirates, and soft tissue biopsies are sources of microorganisms for laboratory testing. Microbial-based treatment end points may help clinicians better identify patients in need of additional or altered dental therapies before the onset of clinical treatment failure, and help improve patient oral health outcomes. Microbiological testing appears particularly helpful in periodontal disease treatment planning. Further research and technological advances are likely to increase the availability and clinical utility of microbiological analysis in modern dental practice.

Flagellar motility of the pathogenic spirochetes

Bacterial pathogens are often classified by their toxicity and invasiveness. The invasiveness of a given bacterium is determined by how capable the bacterium is at invading a broad range of tissues in its host. Of mammalian pathogens, some of the most invasive come from a group of bacteria known as the spirochetes, which cause diseases, such as syphilis, Lyme disease, relapsing fever and leptospirosis. Most of the spirochetes are characterized by their distinct shapes and unique motility. They are long, thin bacteria that can be shaped like flat-waves, helices, or have more irregular morphologies. Like many other bacteria, the spirochetes use long, helical appendages known as flagella to move; however, the spirochetes enclose their flagella in the periplasm, the narrow space between the inner and outer membranes. Rotation of the flagella in the periplasm causes the entire cell body to rotate and/or undulate. These deformations of the bacterium produce the force that drives the motility of these organisms, and it is this unique motility that likely allows these bacteria to be highly invasive in mammals. This review will describe the current state of knowledge on the motility and biophysics of these organisms and provide evidence on how this knowledge can inform our understanding of spirochetal diseases.

Lessons learned and unlearned in periodontal microbiology

Periodontal diseases are initiated by bacterial species living in polymicrobial biofilms at or below the gingival margin and progress largely as a result of the inflammation elicited by specific subgingival species. In the past few decades, efforts to understand the periodontal microbiota have led to an exponential increase in information about biofilms associated with periodontal health and disease. In fact, the oral microbiota is one of the best-characterized microbiomes that colonize the human body. Despite this increased knowledge, one has to ask if our fundamental concepts of the etiology and pathogenesis of periodontal diseases have really changed. In this article we will review how our comprehension of the structure and function of the subgingival microbiota has evolved over the years in search of lessons learned and unlearned in periodontal microbiology. More specifically, this review focuses on: (i) how the data obtained through molecular techniques have impacted our knowledge of the etiology of periodontal infections; (ii) the potential role of viruses in the etiopathogenesis of periodontal diseases; (iii) how concepts of microbial ecology have expanded our understanding of host-microbe interactions that might lead to periodontal diseases; (iv) the role of inflammation in the pathogenesis of periodontal diseases; and (v) the impact of these evolving concepts on therapeutic and preventive strategies to periodontal infections. We will conclude by reviewing how novel systems-biology approaches promise to unravel new details of the pathogenesis of periodontal diseases and hopefully lead to a better understanding of their mechanisms.

Use of PCR to detect Entamoeba gingivalis in diseased gingival pockets and demonstrate its absence in healthy gingival sites

Investigators using light microscopy have identified the protozoan parasite Entamoeba gingivalis from diseased gingival pockets for nearly 100 years. The objective of the present investigation was to develop a molecular biology approach for determining the presence of E. gingivalis in both diseased gingival pockets and healthy gingival sites. For this, a previously developed conventional polymerase chain reaction (PCR) was evaluated and a real-time polymerase chain reaction assay was developed. Paper points were inserted into the base of the sulcus of both diseased gingival pockets and healthy gingival sites. DNA was extracted using the QIAamp DNA mini kit, and subsequently analyzed using conventional and real-time PCR analysis. A previously described primer set specific for the small subunit ribosomal RNA gene (SSU rDNA) of E. gingivalis was used for the conventional PCR. For the real-time PCR, a primer set was designed to amplify a 135-bp fragment inside the SSU rDNA of E. gingivalis. A conventional PCR assay detected E. gingivalis in 27% of diseased gingival pockets. The real-time PCR using a different primer set detected protozoa in 69% of diseased pocket sites. Thus, the latter technique proved more sensitive for detection of E. gingivalis. No E. gingivalis were detected in any of the healthy gingival pocket sites using either type of PCR assay. Results support a concept that the presence of E. gingivalis is associated only with diseased gingival pocket sites. The newly described methodology may also serve to provide a novel eukaryotic cell marker of disease status in gingival pockets.

Effect of glucose on Treponema denticola cell behavior

INTRODUCTION

Treponema denticola inhabits the oral subgingival environment and is part of a proteolytic benzoyl-dl-arginine-naphthylamide-positive 'red complex' associated with active periodontal disease. Spirochetes have a unique form of chemotactic motility that may contribute to their virulence. Chemotaxis is essential for efficient nutrient-directed translocation.

METHODS

We examined the effect of glucose on T. denticola cell velocity, expression of periplasmic flagella proteins, and chemotaxis, e.g. translocation into capillary tubes.

RESULTS

The presence of glucose did not significantly effect T. denticola cell velocity in high viscosity conditions nor did it alter periplasmic flagella protein expression. The addition of glucose to capillary tubes resulted in greater numbers of T. denticola cells in tubes containing glucose. A non-motile mutant did not migrate into capillary tubes containing glucose.

CONCLUSION

These results are consistent with a chemotactic response to glucose that is motility dependent.

Scaling and root planing, systemic metronidazole and professional plaque removal in the treatment of chronic periodontitis in a Brazilian population II - microbiological results

OBJECTIVE

The current investigation evaluated changes in levels and proportions of 39 bacterial species in subgingival plaque samples after scaling and root planing (SRP) alone or in combination with systemic metronidazole and/or professional cleaning in subjects with chronic periodontitis.

METHODS

Forty-four adult subjects (mean age 45+/-6 years) with periodontitis were randomly assigned in four treatment groups, a control (C, n=10) that received SRP and placebo and three test groups treated as follows: T1 (n=12): SRP and metronidazole (M, 400 mg tid) for 10 days; T2 (n=12): SRP, weekly professional supragingival plaque removal for 3 months (PC) and placebo; and T3 (n=10): SRP, M and PC. Subgingival plaque samples were taken from seven sites per subject at baseline and 90 days post-therapy. Counts of 39 subgingival species were determined using checkerboard DNA-DNA hybridization. Significance of differences over time was determined using the Wilcoxon signed ranks test and among groups using ancova.

RESULTS

The mean counts of the majority of the species were reduced post-therapy in the 4 treatment groups. Counts (x 10(5)+/-SEM) of Porphyromonas gingivalis, Tannerella forsythensis and Treponema denticola were significantly reduced in groups T2 and T3. Levels of beneficial species, such as some Actinomyces species, Veillonella parvula, Streptococcus sanguis, Streptococcus oralis and Streptococcus gordonii were minimally affected in levels when the combined therapy was applied (T3). Mean proportions of red complex species decreased from 18.4% at baseline to 3% at 90 days post-therapy in group T3 (p<0.01), from 25.8% to 2.3% in group T2 (p<0.01), from 17.7% to 5.6% in group T1 (p<0.05) and from 19.4% to 8.8% in group C (NS). Proportions of the suspected periodontal pathogens from the orange complex were also markedly reduced in groups T2 and T3.

CONCLUSIONS

All treatments reduced counts and proportions of red complex species. Adjunctive therapy appeared to have a greater effect and also affected members of the orange complex.

Locally delivered antimicrobials for the treatment of chronic periodontitis

The basic treatment of chronic periodontitis is a mechanical debridement of periodontal pockets by scaling and root planing (S/RP) in combination with efficient plaque control. Locally delivered antiseptics (LDA) have been proposed to practitioners and, while subgingival irrigation of antiseptics is still used in clinical practice, the introduction in our therapy of a slow release and sub-gingival delivery of tetracycline has changed the rationale from a mechanical treatment towards a combined therapy for full mouth/sites disinfection. Various antibiotics, antiseptics and resorbable carriers are now proposed with similar targets to arrest disease progression. In chronic periodontitis, LDA cannot be used routinely in combination with S/RP, because of the limited clinical benefit, even if an increased percentage of deep sites may show an improvement. Prospective multicenter studies considering risk factors for disease progression have to be designed to identify patients who may benefit the most from LDA. For non-responding sites or recurrent pockets, the controversies are limited, because a combined S/RP and LDA may avoid the need for surgery. However, the patient cost/benefit ratio needs to be estimated as well as adverse effects in particular antibiotics.

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.

Periodontal disease as a specific, albeit chronic, infection: diagnosis and treatment

Periodontal disease is perhaps the most common chronic infection in adults. Evidence has been accumulating for the past 30 years which indicates that almost all forms of periodontal disease are chronic but specific bacterial infections due to the overgrowth in the dental plaque of a finite number of mostly anaerobic species such as Porphyromonas gingivalis, Bacteroides forsythus, and Treponema denticola. The success of traditional debridement procedures and/or antimicrobial agents in improving periodontal health can be associated with the reduction in levels of these anaerobes in the dental plaque. These findings suggest that patients and clinicians have a choice in the treatment of this overgrowth, either a debridement and surgery approach or a debridement and antimicrobial treatment approach. However, the antimicrobial approach, while supported by a wealth of scientific evidence, goes contrary to centuries of dental teaching that states that periodontal disease results from a "dirty mouth." If periodontal disease is demonstrated to be a risk factor for cardiovascular disease and stroke, it will be a modifiable risk factor since periodontal disease can be prevented and treated. Since the antimicrobial approach may be as effective as a surgical approach in the restoration and maintenance of a periodontally healthy dentition, this would give a cardiac or stroke patient and his or her physician a choice in the implementation of treatment seeking to improve the patient's periodontal condition so as to reduce and/or delay future cardiovascular events.

Repeated subgingival oxygen irrigations in untreated periodontal patients

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

The utility of the BANA test for monitoring anaerobic infections due to spirochetes (Treponema denticola) in periodontal disease

Treponema denticola, Porphyromonas gingivalis, and Bacteroides forsythus each possesses an enzyme(s) that hydrolyzes the synthetic substrate benzoyl-DL-arginine-naphthylamide (BANA). The presence of these organisms in a subgingival plaque sample can be determined by the ability of the plaque to hydrolyze BANA. In the present study, we describe the usefulness of the BANA test at various stages of a clinical trial of the efficacy of metronidazole in the treatment of periodontal disease. A BANA-positive test was significantly associated with high levels and proportions of spirochetes in the plaque, so that it provided information comparable with that which could be obtained by a microscopic examination of the plaque. Patients with such anaerobic spirochetal infections were randomly assigned to a group receiving either metronidazole or placebo (250 mg, three times a day) for one week and whose teeth were scaled and root-planed. The advantages of the decision that metronidazole be used were apparent from the comparison with the results obtained in the patients who received only the scaling and root planing. The initially BANA-positive teeth in the patients treated with metronidazole, scaling, and root planing gained attachment and exhibited a significant reduction in the need for periodontal surgery, when compared with the BANA-positive teeth in the patients who received only placebo, scaling, and root planing. After the conclusion of this therapy, those teeth with persistent BANA-positive plaques had significantly higher proportions and levels of spirochetes than did the teeth with BANA-negative plaques.(ABSTRACT TRUNCATED AT 250 WORDS)

Rationale for the use of antimicrobial agents in periodontal disease

The traditional approach to treating dental decay and periodontal disease has often focused on caries, neglecting periodontal infection. The past 15 years have seen significant advances in the treatment of periodontal disease with antimicrobial therapy, both with and without more traditional debridement or surgery. This article presents an overview of the use of antimicrobials, including an examination of treatment philosophies and the diagnosis of periodontal infection.

The role of spirochetes in periodontal disease

The spirochetal accumulation in subgingival plaque appears to be a function of the clinical severity of periodontal disease. It is not known how many different spirochetal species colonize the plaque, but based upon size alone, there are small, intermediate-sized, and large spirochetes. Four species of small spirochetes are cultivable, and of these, T. denticola has been shown to possess proteolytic and keratinolytic enzymes as well as factors or mechanisms which suppress lymphocyte blastogenesis and inhibit fibroblast and polymorphonuclear leukocyte (PMNL) function. All of these attributes could contribute to periodontal tissue insult. Yet independent of these potential virulence mechanisms, the overgrowth of spirochetes can be clinically useful if simply interpreted as indicating the result of tissue damage. In this case, the spirochetes would be indicators of disease and could be easily monitored by microscopic examination of plaque, or possibly by the measurement of benzoyl-DL-arginine-2-naphthylamide (BANA) hydrolytic activity in the plaque.

Effect of modified Widman flap surgery and systemic tetracycline on the subgingival microbiota of periodontal lesions

33 subjects with evidence of active destructive periodontal disease were treated by modified Widman flap surgery and systemic tetracycline (1 g/day for 21 days). Subgingival plaque samples were taken from 41 sites in 12 of these subjects before and 6 months after therapy for predominant cultivable microbiota studies. Mean pocket depth and attachment levels in the 41 sampled sites were 7.1 +/- 2.9 mm and 7.7 +/- 3.2 mm prior to therapy and 4.8 +/- 2.3 mm and 6.2 +/- 3.4 mm after therapy. B. melaninogenicus and V. parvula were more frequently detected in samples taken after therapy, while S. intermedius, S. morbillorum, S. uberis and W. recta were less frequently detected after therapy. A. actinomycetemcomitans were detected in 7 sites pretherapy and 1 site post therapy. The frequency of detection of B. gingivalis and B. intermedius was virtually unchanged. The mean levels of the Actinomyces sp., A. actinomycetemcomitans, B. gingivalis, B. intermedius, S. morbillorum, S. uberis and W. recta were decreased after therapy, while the mean levels of B. melaninogenicus, S. mitis, S. sanguis II and V. parvula were increased after therapy. V. parvula showed the greatest increase to 8.2% of the microbiota. In the second phase of the study, subgingival plaque samples from 94 sites in the 33 treated subjects were analyzed by predominant cultivable techniques. As a result of therapy, 24 sites exhibited attachment loss greater than 2 mm, 23 sites exhibited "gain" greater than 2 mm and the remaining 47 sites were considered to be unchanging.(ABSTRACT TRUNCATED AT 250 WORDS)

Microbiological and clinical effects of chlorhexidine digluconate and hydrogen peroxide mouthrinses on developing plaque and gingivitis

While the ability of chlorhexidine (CHX) to prevent plaque formation and inhibit the development of gingivitis has been well documented in the literature, the therapeutic value of hydrogen peroxide (H2O2) in preventing gingivitis is in dispute. The purpose of this study was to compare the clinical and microbiological effects of an established therapeutic agent, such as chlorhexidine with that of H2O2 in the experimental gingivitis model. Following a period of stringent oral hygiene, 32 subjects were allocated to 1 of 3 treatment groups which were balanced on the basis of their pre-experimental gingivitis scores. The subjects then refrained from any oral hygiene for 21 days. During this period, they rinsed twice a day with either a placebo, 0.12% CHX, or a 1% H2O2 mouthrinse. After 21 days, supragingival and marginal plaque was collected from each subject and assayed for total cultivable microbiota, total facultative anaerobes, facultative Streptococci, Actinomyces, Fusobacterium, Veillonella and Capnocytophaga. At the end of the experimental period, the group rinsing with 0.12% CHX showed 95% reduction in gingivitis incidence, 100% reduction in bleeding sites, and 80% reduction in plaque scores compared to the group rinsing with placebo. Conversely, the group using 1% H2O2 showed a marginal reduction in gingivitis incidence of 15% and a 28% reduction in bleeding sites compared to the placebo group, but no significant reduction in plaque scores. The microbiological results showed that 0.12% CHX was an excellent broad-spectrum antimicrobial agent which significantly reduced the number of both facultative and obligate anaerobes in plaque.(ABSTRACT TRUNCATED AT 250 WORDS)

Salt and peroxide compared with conventional oral hygiene. II. Microbial results

This study was designed to investigate the effect of conventional oral hygiene (n = 116 subjects) versus a salt and peroxide oral hygiene regimen (n = 115 subjects) on subgingival microorganisms. Subgingival plaque for microscopic evaluation was obtained from eight index tooth sites in each of 231 adult subjects. Microbial forms were microscopically identified at baseline, 8, 16, and 24 months. For both oral hygiene groups, cocci were increased (P less than 0.05) and motile rods were decreased (P less than 0.05) at 8 months and returned to baseline by 16 months. Spirochetes were decreased (P less than 0.05) and remained low through 24 months in both oral hygiene groups. The frequency of agreement between clinical (bleeding) and microbial (greater than or equal to 15% spirochetes or motile rods or greater than or equal to 20% spirochetes + motile rods) criteria for instrumentation was 59.8%. It was also found that fewer total instrumentations for test subjects were observed when microbiological criteria were used as compared with clinical criteria. The greater number of instrumentations based on clinical criteria was highly significant (P less than or equal to 0.001). A significant change in microbial signs associated with peridontal disease may be obtained with either a conventional oral hygiene or a salt and peroxide oral hygiene home care regimen.

Subgingival microflora in bleeding and nonbleeding pockets

The subgingival flora of bleeding and nonbleeding 4-6 mm pockets was investigated using phase-contrast microscopy. Subgingival plaque was sampled from 11 patients with generalized moderate periodontitis. 4 subgingival samples were obtained from each patient, 2 from sites that bled upon standardized probing force and 2 from sites that did not. The amounts of gingival inflammation, supragingival plaque, attachment level and pocket depth were also assessed at each site. The %s of 4 bacterial morphotypes were assessed using phase-contrast microscopy. No significant differences were found in the %s of cocci, motile rods, or spirochetes between bleeding and nonbleeding sites. Significant correlations were found, however, between the % of spirochetes and probing depth, attachment level, and gingival inflammation. The observations indicate that the use of bleeding on probing may not be justified as an indicator of infection by those "periodontopathic" bacteria identifiable by phase-contrast microscopy. However, limitations in the microscopic method may have prevented us from observing differences between the 2 types of sites on a species level.

Comparative longitudinal study of 2 methods of scheduling maintenance visits; 2-year data

This report compares the clinical and microbiological status of 2 groups of subjects with treated periodontis on different maintenance schedules. 43 control (C) subjects were given prophylaxes every 3 months. 40 test (T) subjects were given this service on a flexible schedule according to the proportions of spirochetes and/or motile rods in fresh smears of subgingival scrapings. Both groups were examined every 6 months clinically and microbiologically. This report presents base line, 1- and 2-year data. Generally, mean values for both groups did not differ significantly from one another. Both groups exhibited comparable increases in GI and PLI scores during the first 2 years of this study. No change in probing depth was noted between base line and the 2-year examination. However, a slight increase in attachment level, as determined by probing, was noted in both groups. Both groups also exhibited similar proportions of bacterial morphotypes at base line and subsequent examinations. Disease recurrence, defined as an increase in probing depth of 3 mm or more from base line on any tooth surface during the 2-year period, tended to be more prevalent in the C than in the T group (15/43 C and 9/40 T subjects). However, the proportional difference between the groups was not statistically significant. Subjects with disease recurrence in the T group had greater proportions of spirochetes at base line than subjects in the same group without disease recurrence (20.2% versus 9.8%, p less than 0.01). This difference in proportions persisted if both groups were examined jointly, but was only of borderline significance (16.0% versus 10.5%, p = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of the inorganic salts sodium chloride, sodium bicarbonate, and magnesium sulfate upon the growth and motility of Treponema vincentii

The use of inorganic salt solutions as chemotherapeutic agents in the control of periodontal disease has received considerable attention in the past few years. Although some research has been published on their clinical effectiveness, little is known about their therapeutic activity and bactericidal effects upon oral spirochetes. The present study investigated the effects of varied concentrations of NaCl, NaHCO3, and MgSO4 upon the in vitro growth and motility of Treponema vincentii. Growth determinations were performed using a turbidiometric analysis at 545 nm. Motility was qualitatively studied by direct examination of 200 treponemes in a wet mount specimen. Samples were taken at 24, 48, 72, and 96 hours following inoculation with the treponemes. Concentrations of 0.5 M NaCl, NaHCO3, or MgSO4 totally inhibited the growth and motility of T. vincentii over a 96-hour period. Salt concentrations less than or equal to 0.10 M had little if any effect upon growth and motility. The data support the hypothesis that the bactericidal and antimotility effects of these salts are related more to their concentrations than to the presence of a specific inorganic ion. They also suggest that motility may be a valid indicator of bacterial viability. Before the clinical significance of the results can be ascertained, human studies are needed to establish sulcular salt concentrations which can be achieved with local irrigation and to determine how long bactericidal concentrations can be maintained.

The habitat of periodontopathic micro-organisms

The purpose of the present study was to investigate the significance of oral mucosal surfaces as a habitat of periodontopathic micro-organisms. For this investigation, 7 young adults were selected for an experimental gingivitis study. At the start of the experiment, bacterial samples were taken by means of a sterile swab from 4 oral mucosal surfaces: the buccal mucosa, the vestibular fold, the dorsum of the tongue and a tonsil. All individuals were asked to abstain from oral hygiene procedures in 1 quadrant of the mouth for a period of 23 days. At the end of this period, plaque samples were taken from 4 tooth surfaces by means of a sterile periodontal probe just coronal from the gingival margin. The study included evaluation of spirochetes and motile organisms by means of phase-contrast microscopy and of black-pigmented Bacteroides, Fusobacterium, Actinomyces, Actinobacillus actinomycetemcomitans and Capnocytophaga by means of cultural studies. Results showed a relationship between the prevalence of motile organisms and black-pigmented Bacteroides in samples from both the mucosal surfaces and the 23-day-old plaque. In addition, a relationship was found between the presence of motile organisms on the dorsum of the tongue at the start of the experiment and their prevalence in the 23-day-old plaque. It was suggested that the dorsum of the tongue may function as a nidus for periodontopathic micro-organisms.

The Keyes technique and self-inflicted injuries. Three case reports

Three cases of self-inflicted gingival injuries resulting from the improper use of the Keyes technique are presented. The profession must assume responsibility for studies to determine the safety of the methods of application of the hydrogen peroxide, salt and baking soda mixtures and disseminate this information for the public interest.

Bacterial profiles of subgingival plaques in periodontitis

In this report over 400 subgingival plaque samples taken from over 110 patients were examined microscopically and culturally for 30 bacterial parameters. The patients could be placed into six disease categories based upon clinical criteria. The bacterial profile of each clinical category was generally distinctive of that category. Periodontal patients who had been successfully treated and maintained had plaques that were populated by significantly higher proportions of Streptococcus sanguis, Actinomyces viscosus, A. odontolyticus and S. mutans and significantly lower proportions of B. gingivalis and spirochetes compared to the five untreated disease categories. The spirochetes were the overwhelming microbial type in the plaques of adult periodontitis (AP) patients, averaging about 45% of the microscopic count. The bacteriological results could not distinguish between ADA Type III and IV periodontitis, suggesting that the same type of infection was occurring in an active site in any AP patient. The patients designated as early onset periodontitis (EOP) differed from the other patients by their relative youth and by their significantly higher proportions of Bacteroides gingivalis and/or B. intermedius. Two types of EOP were recognized in which the most diseased variant was characterized by having an average of 49% spirochetes in the plaque. Four localized juvenile periodontitis (LJP) patients were notable in not having detectable A. actinomycetemcomitans. The data indicate that the various types of periodontitis, with the possible exception of LJP are specific anaerobic infections involving spirochetes and to a lesser extent B. gingivalis and B. intermedius.

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.

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.

Orthodontic therapy in patients with juvenile periodontitis: clinical and microbiologic effects

The correction of malocclusions in juvenile periodontitis (JP) patients completing periodontal therapy is a problem of increasing clinical concern to orthodontists, since many teeth with severe alveolar bone loss in these patients can now be successfully treated without extraction. In this report, fixed edgewise orthodontic therapy was carried out after the completion of periodontal therapy on four JP patients. The orthodontic therapy included extensive intrusion of teeth severely affected by JP. Phase-contrast microscopic analysis of subgingival plaque from orthodontically treated teeth was used to monitor longitudinally the effects of fixed orthodontic bands on the subgingival flora and also to monitor the efficacy of topical and systemic antimicrobial therapy aimed at suppression of suspected periodontopathic bacteria. Orthodontic movement was completed on most periodontally compromised teeth without significant evidence of additional deterioration in periodontal status. However, within the first 6 months of orthodontic band placement, all patients had significant increases in the number of spirochetes and motile rods in their subgingival flora. Three of the patients also developed high levels of crevicular polymorphonuclear leukocytes around orthodontically treated teeth, indicating significant subgingival inflammation. Intensive antimicrobial measures, including topical inorganic salt applications and systemic tetracycline, were helpful in limiting clinical inflammation and subgingival colonization by periodontopathogens during orthodontic therapy. The results demonstrate that successful orthodontic repositioning can be carried out in treated JP patients. In addition, bacteriologic monitoring and chemotherapeutic suppression of periodontal pathogens may be valuable in the prevention of further destructive periodontal disease activity in periodontitis patients undergoing orthodontic therapy.

The effect of Keyes' method of oral hygiene on the subgingival microflora compared to the effect of scaling and/or surgery

The present study was conducted on 18 individuals to determine if Keyes' method of oral hygiene would present an alternative to traditional periodontal therapy in terms of establishing a subgingival microflora compatible with periodontal health. Oral hygiene, gingival conditions and subgingival microbial proportions assessed by dark field microscopy were measured at baseline, then once every 2 weeks for the remainder of this 8-week study. In addition, probing depths and bleeding on probing were evaluated. Group I (9 patients) was treated non-surgically, while Group II (9 patients) had received surgical therapy within the last 4 years. Both groups received routine scaling and root planing (Sc/RP) on one arch at time 0, and both were instructed to use Keyes' method of oral hygiene on one side of the mouth while the other side served as a control. This yielded a split-plot experimental design which permitted examination of the effects of Keyes' method of oral hygiene, Sc/RP and surgery. The results revealed no statistically significant differences between Keyes' method of oral hygiene and conventional oral hygiene in patients treated with a single session of Sc/RP. When scaling was not employed, Keyes' method was more effective than conventional oral hygiene. Surgical status was found to be the most significant factor in reducing clinical indicator values and establishing control of the subgingival microflora. In summary, oral hygiene alone had only minimal effects on subgingival microbial proportions. The primary antimicrobial effect observed, as evidenced by shifts in subgingival morphotype proportions, was produced by the Sc/RP procedure. This effect was enhanced by improved access (surgical status).

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.

Comparative differential dark-field microscopy of subgingival bacteria from tooth surfaces with recent evidence of recurring periodontitis and from nonaffected surfaces

Ninety-two subjects with a history of treatment for chronic periodontitis were monitored on a regular basis for an average period of 10.7 months. During this monitoring period, in spite of their participation in a preventive maintenance program, 19 subjects out of 92 showed evidence of significantly increased probing depth (greater than or equal to 3 mm from base line measurements) on at least one tooth surface, or approximately 1% of the dental units at risk in this population. A comparison of differential microscopic counts of subgingival bacteria from the affected tooth surfaces with a pooled sample of 6 other surfaces with the greatest probing depth, in the same mouth, taken at the same appointment, revealed no significant differences between proportions of coccoid cells, spirochetes, motile rods or other cell types. These findings suggest that disease recurrence, as measured by a comparatively rapid increase in probing depth, might be accounted for on the basis of the following hypotheses: an alteration in the host response without a detectable change in the composition of the subgingival microbiota, a qualitative change in the microbial flora not detectable by a microscopic assay, relatively brief episodes of disease activity which may be accompanied by brief, transient, qualitative changes in the local microbiota that cannot be readily detected by biannual examinations.