Microbes and periodontal disease

Autoantibodies directed to extracellular matrix components in patients with different clinical forms of periodontitis

BACKGROUND

Periodontal disease occurs in different clinical forms, from mild and easily controllable to more aggressive inflammatory manifestations, with difficult clinical or surgical control. There is evidence that a local autoimmune reaction may participate in the onset and persistence of the aggressive forms of periodontal disease. As the underlying mechanism in this process is not fully understood, we decided to investigate whether patients bearing this form of disease presented higher levels of antibodies directed to extracellular matrix (ECM) components such as type I collagen, fibronectin, and laminin.

METHODS

Three groups of patients were selected by clinical criteria: 22 subjects with aggressive periodontitis (AgP) = group A; 18 subjects with chronic periodontitis (CP) = group B; and 10 healthy (H) volunteers without periodontal disease = group C. Autoantibody levels were evaluated in the sera of these patients using the enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

The levels of autoantibodies directed to ECM components (type I collagen, fibronectin and laminin) in the sera of patients with AgP and CP were shown to be statistically different (P <0.05).

CONCLUSIONS

Although the present findings suggest an involvement of autoantibodies directed to ECM components per se in the pathogeny of certain types of periodontal disease, the available data do not support the classification of the lesions as autoimmune. Nevertheless, the findings open a possibility for the development of an additional method for a differential diagnosis of the aggressive forms of periodontal disease.

Preventive strategies in oral health promotion

The biofilm control is a considerable factor in the prevention and treatment of oral diseases as caries and periodontal disease. However, according to the literature, the collective programs show frustrating results at long-term due to difficulty to change the behavior of the participant individuals. Therefore, taking into consideration the model of the dental practice in Brazil, where the population has an oral health needfulness, the purpose of this study is to introduce different strategies that allow the accomplishment of collective programs, so that they succeed in the promotion of the oral health either in individual or collective level.

Salivary glycoproteins as indicators of oral diseases

The present study deals with the estimation of total carbohydrate, protein bound carbohydrate, bound fucose and sialic acid along with total protein in disease conditions like gingivitis, periodontitis and their comparison with the normals.The neutral hexose values in gingivitis (8.08±2.20mg/100mg protein) and periodontitis (12.5±2.16mg/ 100mg protein) decreased significantly when expressed per 100 mg protein compared to normals (19.8±1.89mg/100mg protein). This might be because of higher protein concentration in these two clinical conditions. The ethanol insoluble hexose values were significantly reduced in both these conditions compared to controls (3.71±1.64,5.91±1.63,7.65±0.86mg/100mg protein respectively). The ethanol soluble hexose values were also found to be drastically reduced. This decrease in saliva appears to be characteristic feature of oral diseases. In gingivitis and periodontitis fucose level was found to be increased compared to normals when expressed as a function of salivary volume. However in terms of protein concentration the values in gingivitis (2.95±1.59), periodontitis (3.26±0.98) and normals (3.20±0.50mg/100mg) were not different. Sialic acid in ethanol insoluble fraction of salivary samples mg/100mg protein was found to be significantly reduced in both gingivitis (0.78±0.33) and periodontitis (0.95±0.31) compared to controls (1.92±0.33).

Plaque removal with variable instrumentation

The purpose of this study was to evaluate dental plaque removal in a normal healthy mouth, during routine oral hygiene appointments using different techniques and without the use of any disclosing agents. 12 dental hygienists, randomly selected from a continuing education course, were asked to perform oral hygiene on the same patient to remove all the supra-gingival plaque without any time restriction and without the use of a disclosing agents. The plaque index score (O'Leary) was assessed before and after each session with the use of fluorescine and UV light source by an independent examiner. 3 groups of instruments were utilized: group A: ultrasonic scalers + prophy cups; group B: ultrasonic scalers + prophy cups + dental floss; group C: Gracey curettes + prophy cups. While no group was able to remove all the plaque, groups B and C performed significantly better.

Scanning electron microscopy of microbial colonization of 'rapid' and 'slow' dental-plaque formers in vivo

The aim was to investigate the morphological features of supragingival plaque development in 'rapid' and 'slow' plaque formers using scanning electron microscopy (SEM). Forty-nine healthy volunteers were screened for their plaque-formation rate after 3 days of oral hygiene abstinence using the Plaque Index (PI). Five with the highest and six with the lowest mean PI were selected as 'rapid' and 'slow' plaque formers, respectively. Six enamel blocks measuring 2 x 2 x 1 mm were bonded onto the buccal surfaces of the upper left canine, premolars and first molar of each selected participant after a series of prophylaxes and oral hygiene instruction to ensure clinical gingival health. A 14-day period with no oral hygiene began thereafter. An enamel block was removed at 3 hr, 6 hr, 1 day, 3 days, 7 days and 14 days from each individual, fixed, and processed for SEM. Quantitatively, more bacteria were observed on the 3-hr to 1-day enamel blocks of the 'rapid' plaque formers. The day-1 specimens of the 'rapid' group showed a more complex supragingival plaque structure than those of the 'slow' group. From days 3 to 14, during the maturation period of supragingival plaque, there were no discernible differences between the two groups except that intermicrobial matrix was more prominent in the 'rapid' group. In general, the development of supragingival plaque followed known patterns. These observations indicate that morphological features of supragingival plaque in 'slow' and 'rapid' plaque formers differ, especially in the early developmental phases.

Bacterial morphotypes of 3-day old plaque in Chinese. A pilot study

The aim of the this study was to estimate the % distribution of bacterial morphotypes of supragingival plaque in Chinese subjects after 3 days of no oral hygiene. 36 dental students, hygienists or dental surgery assistants (mean age: 24.3 years) were recruited. Prophylaxis and oral hygiene reinforcement were given 1 x a week for 3 weeks to obtain gingival health and a 3-day period without any plaque control started afterwards. At the end of the 3-day period, the plaque along the gingival margin of the upper right central incisor was removed and direct Gram stained smears were prepared for light microscopy. Bacteria were classified as gram-positive or gram-negative cocci, rods, filaments, fusiform organisms, spirilla or spirochetes. A differential count of 200 organisms from 3-6 microscopic fields was performed and the results expressed as a % of the organisms counted. Results from the 36 direct smears showed approximately 83% (range: 52%-96%) of the organisms to be gram-negative while gram-positive bacteria comprised only a minority of about 12% (range: 0.7%-43%). This result is remarkably different from previous reports from the West where gram-positive bacteria were the predominant bacterial types noted in early supragingival plaque. Further longitudinal studies involving both microscopy and bacteriological culture will be necessary to confirm this finding.

The apical border plaque in severe periodontitis. An ultrastructural study

This study concerns the apical border (AB) plaque in relation to severe forms of periodontitis (SP), including juvenile, post-juvenile, and rapidly progressing periodontitis. Twenty-four (24) teeth from 16 patients with SP were examined by transmission electron microscopy (TEM). The AB was not discrete, with islands of bacteria in the so-called plaque-free zone (PFZ). Coronal to the AB the established plaque consisted of a layer of Gram-positive cocci and ghost cells and a superficial layer mainly of Gram-negative morphotypes, including cocci, rods, filaments, fusiforms, and spirochetes. The most apical apparently intact organisms in the PFZ were in bacterial islands or in isolation and were predominantly Gram-negative cocci and rods, with ghost cells in abundance. Ruthenium red, alcian blue-lanthanum nitrate, and safranin O were used to label matrix polyanionic macromolecules, and periodic acid (thiosemicarbazide) silver proteinate for intracellular polysaccharide (IPS). The matrix components were mainly fibrillar. Many intact bacteria exhibited extracellular polysaccharides or glycocalyces associated with their cell wall, and cytoplasmic IPS granules. The latter varied in distribution and were evident even in the most apically advanced intact microorganisms. The results indicate that IPS and some matrix features of the apical border plaque in severe periodontitis in certain aspects resemble those of sub-contact area plaque on children's teeth, in health or associated with early chronic gingivitis, and with those in chronic adult periodontitis. They also suggest the establishment of acidic regions in the microniche at the bottom of the periodontal pocket in the various forms of periodontitis differing in rate of progression. It was concluded that there was a limited range of intact bacterial morphotypes in the apical border plaque in severe periodontitis, similar to those in chronic adult periodontitis.

Coaggregation studies of the Eubacterium species

Eubacterium species are gram-positive anaerobic rods that are frequently isolated from subgingival plaque of periodontal pockets. Five Eubacterium species were tested for their ability to coaggregate with 33 oral bacterial strains. Using visual and turbidimetric assays, coaggregation was observed among Eubacterium brachy, Eubacterium nodatum, Eubacterium alactolyticum and Eubacterium limosum strains only when tested with Fusobacterium nucleatum strains; Eubacterium saburreum displayed only weak coaggregation ability. Coaggregation between F. nucleatum and the Eubacterium species was observed over a wide range of concentrations of each organism. The F. nucleatum strains contained a heat labile and the Eubacterium species a heat stabile coaggregation receptor. Arginine, histidine, lysine and glycine inhibited the coaggregation between F. nucleatum and the Eubacterium species. Sugars and other amino acids tested did not inhibit the observed coaggregation. Rabbit anti-F. nucleatum serum completely inhibited coaggregation, but anti-E. brachy serum and normal rabbit serum did not. As these anaerobic microorganisms are frequently isolated from the same oral lesions, the surface interactions observed may be important in the pathogenesis of these polymicrobic infections.

Hand versus ultrasonic instrumentation in the removal of endotoxins from root surfaces in vitro

The goal of this study was to determine whether ultrasonic scalers are as effective as curettes in providing fibroblast attachment to the scaled root surfaces. Extracted, peridontally involved teeth were cut along the sagittal plane; then one half of the root was curetted, the other half ultrasonically scaled. In addition, monkey kidney fibroblasts were suspended in a petri dish containing root fragments of the tooth halves. At the same time, control dishes without fragments were mounted. All dishes were treated with radioisotopic techniques. There was no significant difference in fibroblast growth between peridontally involved root surfaces treated using curettes or ultrasonic scalers. Both treatments caused the roots to lose their toxicity. The limitations of ultrasonic scalers in terms of shape, size and awkward handling need to be considered when choosing the approach that best suits each case.

Bacterial penetration of the pocket tissues in juvenile/postjuvenile periodontitis after the presurgical oral hygiene phase

Previous ultrastructural investigations of untreated sites of both adult and juvenile periodontitis have shown bacteria within the periodontal soft tissues. In the present study biopsies of the soft tissue walls of deep pockets from seven patients with juvenile (JP) or postjuvenile periodontitis (PJP) were removed at the end of the presurgical oral hygiene phase of treatment and examined in the transmission electron microscope. Bacteria were sparse, regardless of the level of tissue breakdown, both on the surface and within the superficial layers of the epithelium, deep to the basement membrane and throughout the underlying connective tissue. Of the 140 blocks from 20 biopsies, only two revealed intratissue accumulations of microorganisms. The organisms observed were gram-positive or gram-negative and appeared to be exclusively coccoid or rod-shaped. It is suggested that the reduced tissue content of bacteria reflects the establishment of adequate oral hygiene. Evidently either the tissue content of bacteria is less than has been reported previously or the host response is able to cope with residual bacteria that have penetrated the soft tissue.

Periodontal attachment loss associated with proximal tooth restorations

This study documents that periodontal attachment loss is greater adjacent to restored tooth surfaces than adjacent to unrestored tooth surfaces. This finding emphasizes the importance of the prevention of caries and poor restorations.

Clinical alterations in relation to the morphological composition of the subgingival microflora following scaling and root planing

The aim of the present study was to relate shifts in the composition of subgingival plaque in periodontal pockets to alterations of the clinical periodontal conditions following a single course of subgingival scaling and root planing during a period of professional supragingival plaque control. For this purpose, 36 pairs of contralateral periodontal pockets in 10 subjects with moderately advanced periodontitis were assessed for the degree of gingival inflammation, probing pocket depths, bleeding on probing, attachment levels and the amount of supragingival plaque. In addition, samples of subgingival plaque were analyzed morphologically by dark-field microscopy. All patients received detailed information about proper oral hygiene and every 1-2 weeks, professional removal of supragingivally located deposits. When the oral hygiene standard had been sufficiently improved, 1 course of subgingival scaling on 1 side of each jaw only (test side) was carried out. Clinical and microbiological examinations were repeated after the scaling as well as after 2 and 6 months, while patients were recalled for supragingival prophylaxis every 2nd to 4th week. Our data showed that a single course of subgingival scaling and root planing resulted in reduced probing depths, a gain in clinical attachment and a shift in the composition of the subgingival microflora to a composition found in relatively healthy periodontal conditions. In relatively shallow pockets, however, a possible influence of repeated sampling on the subgingival microflora could not be ruled out. Bleeding on gentle probing was a reliable parameter for predicting a subgingival microflora where motile bacteria hold an increased portion.(ABSTRACT TRUNCATED AT 250 WORDS)

Concentration of doxycycline in human gingival fluid

Doxycycline is a synthetic tetracycline compound whose main advantages over tetracycline hydrochloride are increased oral absorption, prolonged serum half-life and decreased gastrointestinal side-effects. The purpose of this study was to measure the concentration of doxycycline in gingival fluid and blood after oral administration. 4 volunteers were given doses of 100 mg doxycycline every 12 h on the first day of antibiotic administration followed by a maintenance dose of 100 mg per day for an additional 4 days. 3 of these volunteers were also given tetracycline hydrochloride every 6 h for 5 days either 1 month before or after doxycycline administration to compare gingival fluid levels of these 2 tetracycline compounds. Gingival fluid was sampled from 4 gingival sites in each volunteer at hourly intervals from hours 0 to 6, 9, 24, 27, 48 to 54, 57, 72, 75, 96 to 102 and 105. Blood was sampled by finger puncture at hours 0, 3, 6, 24, 48, 54, 72, 96 and 102. Antibiotic levels in gingival fluid and blood were measured using an agar diffusion assay method. The results demonstrated that doxycycline achieved much higher levels in the gingival fluid than in blood and yielded comparable gingival fluid levels to those achieved by tetracycline hydrochloride. Doxycycline levels in gingival fluid ranged between 1.2 micrograms/ml and 8.1 micrograms/ml in the first 24 h and generally achieved 3-10 micrograms/ml after 48 h. Blood levels after 48 h ranged between 2.1 micrograms/ml and 2.9 micrograms/ml. Tetracycline hydrochloride in gingival fluid after 48 h was generally in the range of 4 micrograms/ml-10 micrograms/ml with blood levels between 2.2 micrograms/ml and 3.4 micrograms/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Systemic antibody response of clinically characterized patients with antigens of Eubacterium brachy initially and following periodontal therapy

Eubacterium brachy, a gram-positive anaerobic rod, has been implicated by cultural studies to be associated with the microflora of periodontal diseases. Serum samples from 184 clinically characterized patients were evaluated in a standardized enzyme-linked immunosorbent assay (ELISA) for reactivity to E. brachy antigens. Sera from clinically healthy subjects (HS) served as controls. Sera from rapidly progressive periodontitis (RP) patients demonstrated significantly greater reactivity by ELISA than did HS when reactivity with E. brachy antigens was determined (P less than 0.05). Juvenile periodontitis (JP) and adult periodontitis (AP) patients did not differ in reactivity by ELISA from HS (P greater than 0.05). Three to 4 years following successful periodontal therapy, reactivity was not significantly altered in any patient group (P greater than 0.05). The possible significance of these findings and the importance of an extracellular antigen of E. brachy in the immunopathology of periodontal diseases are discussed.

Proteases and their inhibitors in chronic inflammatory periodontal disease

This article reviews the current knowledge of the sources, function and interactions of proteolytic enzymes and their inhibitors in chronic inflammatory periodontal disease. Proteolytic tissue degradation is a typical phenomenon in chronic inflammatory periodontal disease. The proteolytic enzymes can be both host- and bacteria-derived. The proteases of the inflammatory cells are aimed for digestion of bacteria, enhanced locomotion through connective tissue, demarcation of the site of infection and tissue remodeling. Uncontrolled release of proteases in inflammation causes self-digestion and tissue destruction. The potential of the bacterial proteases in degradation of connective tissue is not yet known. Biochemical and immunologic mediators of inflammation are released by proteolytic reactions. Immunoglobulin-cleaving proteases present a specific mechanism in perturbation of host defenses. The 2 main protease inhibitors in serum, alpha-1-antitrypsin and alpha-2-macroglobulin, are also present in the gingival tissue fluid guarding the function of proteases. It has been suggested, although not confirmed, that deficiency in serum protease inhibiting capacity could be correlated with susceptibility to periodontal disease. Mucous secretions contain local low molecular weight protease inhibitors, but their possible rôle in saliva is not known. Bacteria-derived, antiproteolytic short peptides may prove to be useful in pharmacological control of tissue destruction at inflammatory sites.

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

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

Gingival wound healing in the presence of plaque-induced inflammation

An accelerated loss of connective tissue attachment has been reported following surgery in plaque-infected dentitions. It was the purpose of the present study to evaluate histologically the healing of incisional wounds in the gingival supracrestal region in the presence and absence of bacterially induced inflammation. In the experimental group, marginal periodontitis was induced around the teeth by tying plaque-retentive ligatures at the gingival margins and 10 weeks later an incisional wound was made from within the gingival sulcus to the crest of the bone. In the control group, similar incisional wounds were made in normal gingiva. In each group, three specimens were available for histologic and histometric analysis 1, 3, 7 and 21 days after wounding. In the control group, the wound healing sequence in the supracrestal region was similar to that reported following incisional cutaneous wounds. In the experimental group, epithelial continuity across the wound was re-established earlier, and marked invagination of epithelium occurred into the incision. This invagination was significantly greater than in control specimens at all time points. In addition, within the experimental group a second significant epithelial migration into the wound occurred between 7 and 21 days. The epithelial invagination extended through the major portion of the supracrestal area and terminated near the cementum surface. It is conceivable that marked epithelial invagination into a supracrestal wound may predispose to an accelerated loss of connective tissue attachment.

Bacterial invasion of periodontal tissues in advanced periodontitis in humans

Bacterial invasion of the pocket epithelium and underlying connective tissue was found in seven cases of advanced human periodontitis. Four cases showed invasion of the epithelium as well as the connective tissue while in the other three cases bacterial invasion was limited to the pocket epithelium. The microorganisms observed included cocci, rods, filaments, fusiforms and spirochetes and these were morphologically similar to those observed in the apical zone of the subgingival plaque. Most bacteria showed typical Gram-negative cell walls. Bacteria were seen in enlarged epithelial intercellular spaces and among debris of disintegrated epithelial cells. In the connective tissue the bacteria were seen among remnants of collagen fibers and degenerated fibroblasts. Identification of the invading microorganisms may assist in understanding the pathogenesis of chronic periodontitis.

Fluoride-treated roots and viability and attachment of human gingival fibroblasts

Topical fluoride treatment is used to help prevent root caries. It may also be useful in periodontal therapy because of its antimicrobial property. In addition, for therapeutic new attachment to occur, the fibroblasts approximating the treated root surface should remain viable, and should also be able to attach and grow onto the treated root surface. These conditions, at least, are required for fluoride not to interfere with new attachment. This study was designed to determine whether treatment of roots with fluoride adversely affects human gingival fibroblasts in culture; and what effect fluoride treatment has on attachment and growth of cells to the root surface. Cells originally obtained from human gingiva were allowed to grow to confluency in multi-well tissue culture petri dishes, and were then incubated for 24 hr in the presence of root sections as follows: (1) no treatment; (2) root-planed only; (3) 2% NaF only; (4) root-planed + 2% NaF; (5) root-planed + citric acid, pH 1 + 2% NaF. In addition, cells were plated onto roots similarly treated and were subsequently allowed to incubate for 72 hr. Viability of cells was determined by exclusion of vital dye and 51Cr retention. Attachment and growth of cells were determined by histology and scanning electron microscopy. Results indicated that, after 24 hours' exposure, there was little or no difference in cell viability between different treatment groups and control cultures. Also, all roots which had been planed accommodated cell attachment, regardless of additional treatment rendered.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of various root surface treatments on the attachment and growth of human gingival fibroblasts: histologic and scanning electron microscopic evaluation

Human teeth extracted because of advanced periodontal disease were obtained. The portions of the roots which had been exposed in periodontal pockets were either untreated or were treated with root planing or citric acid, or root planing followed by citric acid. Human gingival fibroblasts were then added to the roots so treated and were allowed to incubate for 72 h. The ability of cells to attach to and grow onto these roots was assessed by means of gross evaluation of staining intensity and by histologic and scanning electron microscopic observation. The results of multiple experiments in each root-treatment category indicated that only roots which had been planed, whether or not citric acid demineralization was used, promoted cell attachment and growth. In addition, there were no discernible morphologic differences in the cells which were plated onto roots which were root planed only, compared to those which were root planed and citric-acid treated. In both situations too, the cells displayed morphology typical of human gingival fibroblasts in culture.

Denture cleansing: a comparison of two methods

A paste brushing method (Complete) and soaking in either of two denture cleanser tablet solutions (Efferdent or Polident) were compared for denture cleansing effectiveness as measured by plaque level. The 12-week product use period with weekly evaluations allowed an assessment of plaque reaccumulation on the denture surface as well as the effect of a single cleansing event and the contribution of bleaching to the total plaque-cleansing activity. The paste/brushing method was consistently the more effective procedure for removal of denture plaque. However, the bleaching effects of the effervescent tablets could be useful in an overall denture hygiene program.

Phase contrast microscopy of microbial aggregates in the gingival sulcus of Macaca mulatta. Subgingival plaque bacteria in macaca mulatta

The objective of this study was to study the relationship of microbial aggregates in the subgingival crevice to changes in periodontal health in Macaca mulatta. The sample included 68 oral sites from 17 Rhesus monkeys of various ages. The periodontal health of each site was evaluated using Plaque and Gingival Indices and crevice depth measurement. The subgingival plaque samples were examined by phase contrast microscopy and recorded on 16 mm film. A Microbial Index was developed based on a qualitative estimate of the numbers of organisms, morphology of predominant organisms, and the presence or absence of motility. The Microbial Index was demonstrated to be simple in use and highly reproducible. The findings indicate that changes in the Microbial Index are consistent with tissue changes seen in the periodontal status in M. mulatta. From this preliminary study, the oral flora of adult M. mulatta appears to have sufficient similarities to human oral flora to be used as a microbial model for experimental periodontal disease research. Future studies to refine and confirm the validity of the Microbial Index are warranted. It may prove to be a useful tool to monitor the effect of various treatment modalities on the periodontal flora and to determine the presence or absence of active disease.

Effect of various root surface treatments on the viability and attachment of human gingival fibroblasts

Periodontally involved extracted human teeth were either untreated or were treated with root planing, citric acid, or root planing followed by citric acid. Following incubation of the roots, in the presence of normal human gingival fibroblasts for varying periods of time, cells were assayed for viability by radioactive label (51Cr). In addition, the ability to promote attachment and growth of gingival fibroblasts, by root treatment as above, was observed. The results of multiple experiments in each category indicated strongly that none of the roots, regardless of treatment or nontreatment, had any significant adverse affect on the viability of the cells. However, only root-planed roots, whether or not citric acid was used, promoted cell attachment and growth.

Tetracycline: levels achievable in gingival crevice fluid and in vitro effect on subgingival organisms. Part I. Concentrations in crevicular fluid after repeated doses

The concentration of tetracycline in gingival crevice fluid and blood was determined using a sensitive bioassay after oral administration of repeated doses of tetracycline. Crevicular fluid was sampled by an intracrevicular technique from four gingival sites in each individual and blood was obtained by finger puncture. Four volunteers received doses of 250 mg of tetracycline-HCl either every 6 hours or every 12 hours and were sampled at hours 0 to 15, 21 to 36, 48 to 60 and 96 to 102. Volunteers given 250 mg every 6 hours had average crevicular fluid concentrations between 4 to 8 micrograms/ml and blood concentrations between 2 to 2.5 micrograms/ml after 48 hours. The levels in crevicular fluid and blood of volunteers who received 250 mg every 12 hours were 2 to 4 micrograms/ml and 0.3 to 1.4 micrograms/ml respectively after 48 hours. The results demonstrated that after repeated doses of tetracycline the crevicular fluid levels were typically 2 to 4 times the blood levels.

The use of antimicrobials in the mouth

The use of antimicrobials in the mouth, particularly in the form of antiseptic mouth-washes, is widely practised. The purposes for which such treatment is used are very diverse and reports are widely scattered throughout the literature. It is the purpose of this review to bring together diverse literature references and to present a short but comprehensive survey of the subject.

A comparative, scanning electron microscopic study of supragingival and subgingival calculus

The morphology of supragingival and subgingival calculus on extracted teeth was studied with the scanning electron microscope. Oral, crevicular, and fracture surfaces were examined. Both subgingival and supragingival calculus had a heterogenous core covered by a soft, loose layer of microorganisms. On supragingival calculus this layer was dominated by filamentous microorganisms while subgingival calculus was covered by a mixture of cocci, rods and filaments. The supragingival covering of filaments was oriented with the filaments approximately perpendicular to and in direct contact with the underlying dense calculus. This arrangement was rarely seen subgingivally where there was no distinct pattern of orientation. Some of the specimens of sub- and supragingival calculus were treated with sodium-hypochlorite. These lost the soft covering, and channels the same size as the filamentous organisms were found penetrating into the calculus. They were oriented prependicular to the surface in supragingival calculus but had no specific direction in subgingival calculus. The appearance of the channels supports the concept that calcification starts between the microorganisms in both subgingival and supragingival calculus.

Gingival fluid fucose to protein ratios as indicators of the severity of periodontal disease

Total fucose and protein was measured in gingival fluid samples collected from 16 human subjects. A significantly higher total protein concentration was found for the control (clinically normal) group when compared to the experimental (severe clinical inflammation) group. This is probably due to the higher gingival flow rate found in the experimental group. The total fucose analyses showed no statistical difference between both groups, but when fucose to protein ratios were studied, a significantly higher ratio was found for the experimental group when compared to the controls. This probably represents the breakdown of plasma and tissue glycoproteins which may occur as a result of inflammation.

Bacterial endotoxin: a role in chronic inflammatory periodontal disease?

A review of current information was undertaken examining suggested roles for bacterial endotoxin in periodontal disease. Evidence for the presence of endotoxin in plaque, gingival crevicular fluid and periodontally involved cementum is discussed. The biological effects of endotoxin are numerous, and its abilities to induce tissue inflammation, resorb rat foetal bone, activate the complement pathway, stimulate macrophages and activate immune responses are examined in relation to the suggestion that endotoxin is an important factor in the pathogenesis of periodontal disease.

A review of chemotherapeutic plaque control

Of the plaque-control agents studied, it would appear that chlorhexidine is the most suitable agent to prevent plaque accumulation and the development of gingivitis. It also is attractive to speculate on the possibilities of a commercially available mouthwash. A trio of antibiotics--kanamycin, spiramycin, and vancomycin--may prove of value in the treatment of severe gingival and periodontal disease. The ultimate role of xylitol has yet to be determined. Regardless of the agent selected, access to the gingival sulcus region seems critical.

Selective medium for isolation of Eikenella corrodens from periodontal lesions

The addition of 5 microgram of clindamycin per ml to a modified Todd-Hewitt growth medium permitted the ready enumeration of Eikenella corrodens from deep periodontal lesions because it allowed differential growth amongst the periodontal pocket gram-negative microaerophilic-anaerobic flora, maximized the numbers of E. corrodens in such culture, and inhibited the growth of most of the other confounding microorganisms.