Relationship of subgingival plaque flora to lysosomal and cytoplasmic enzyme activity in gingival crevicular fluid

Relationship between lactate dehydrogenase activity in saliva and oral health status

OBJECTIVE

Lactate dehydrogenase (LDH) activity in serum increases as a marker of cellular necrosis. LDH activity in saliva could constitute a specific indicator of oral mucosal lesions with tissue breakdown including periodontal disease. The aim of this study was to determine LDH activity in saliva, assessing inter-individual variations with regard to the oral health status.

MATERIALS AND METHODS

An oral and perioral examination was performed on a study group of 175 volunteers, to assess the number of missing teeth, caries, fillings, dental prosthesis, periodontal status and temporomandibular joint condition. LDH activity was determined from stimulated whole saliva.

RESULTS

After adjustment by age, gender, smoking habits, missing teeth and use of removable prosthesis, the multivariate analysis showed that increased LDH activity was associated with periodontal disease, specifically with the presence of calculus and pockets greater than 5mm.

CONCLUSION

LDH activity in whole saliva could be useful as a biochemical marker of periodontal status.

The influence of diabetes on gingival crevicular fluid beta-glucuronidase and interleukin-8

OBJECTIVES

Polymorphonuclear neutrophil (PMN) dysfunction is associated with diabetes. We examined the gingival crevicular fluid (GCF) beta-glucuronidase (BG) and interleukin-8 (IL-8) levels of periodontitis patients with and without type 2 diabetes mellitus (DM).

MATERIAL AND METHODS

Forty five adults with type 2 DM and 32 adults without DM, both with chronic periodontitis were enrolled. GCF was collected from eight posterior sites in each quadrant, and periodontal parameters were recorded. GCF was assayed for IL-8 by ELISA and BG by a fluorometric assay.

RESULTS

GCF IL-8 was positively correlated with probing depth (PD), and GCF BG but not clinical attachment level (CAL), bleeding on probing (BOP), or plaque index (PI). In contrast, GCF BG was strongly correlated with each of the clinical measures of periodontal disease. Subjects with DM significantly lower levels of both BG (73.0+/-44.8 versus 121.9+/-84.6 pg/sample; p=0.002) and IL-8 (32.1+/-33.1 versus 90.8+/-83.2 pg/sample; p<0.0001) even after adjustments for age, gender, PD, CAL, BOP, and PI. Neither BG nor IL-8 was correlated with HbA1c levels in subjects with DM.

CONCLUSION

These data suggest that an inadequate local response by PMN, partially explained by an altered chemokine gradient, may contribute to periodontal disease in patients with type 2 DM.

Association of gingival crevicular fluid and serum intracytoplasmic enzyme levels in periodontally healthy homozygous (major) beta-thalassemia patients

OBJECTIVE

To assess tissue necrosis in beta-thalassemia major patients, as in other areas of medicine, lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) have been widely used. These markers of tissue degradation have also been studied in the gingival crevicular fluid (GCF) in relation to periodontal disease status. The purpose of this study was to investigate whether periodontal diagnostic tests based on these markers of tissue degradation are influenced from the enzymes' levels in serum and, therefore, could be used in the assessment of the patient's periodontal status.

MATERIAL AND METHODS

Forty-four periodontally healthy, homozygous beta-thalassemia patients were enrolled in the study. GCF and serum samples were obtained and the levels of AST, ALT and LDH were determined; the measurements took place in an automated analyzer (Hitachi 777) using the kits of Roche Company.

RESULTS

Lack of correlations between serum and GCF enzyme levels was demonstrated. Serum LDH and serum AST, serum AST and serum ALT are significantly positively correlated. Concerning the GCF, AST and ALT were proved to be significantly positively correlated.

CONCLUSIONS

Elevated values of LDH, ALT and AST in serum do not constitute a confounding factor in GCF measurements of the respective enzymes.

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.

Analysis of human gingival tissue and gingival crevicular fluid beta-glucuronidase activity in specific periodontal diseases

BACKGROUND

Beta-glucuronidase (betaG) is one of the enzymes involved in the destruction of non-collagenous components of the extracellular matrix. It is also considered an indicator or predictor of periodontal disease activity. The present study was conducted to determine the presence and the levels of betaG activity in gingival tissue and gingival crevicular fluid (GCF) in periodontal disease and health status. The validity of 2 expressions of data, total betaG activity versus betaG concentration, and the correlations between clinical periodontal status and betaG profile was also evaluated.

METHODS

betaG activities in gingival tissues and GCF samples from 57 individuals, divided into 3 equal groups of adult periodontitis (AP), early-onset periodontitis (EOP), and periodontally healthy subjects were spectrophotometrically examined.

RESULTS

Both patient groups had higher betaG levels in both gingiva and GCF than controls. Significant differences were observed among all groups when total GCF betaG activities were examined (P <0.05). However, the difference between AP and controls was not significant when concentration values were compared (P >0.05). The highest GCF betaG activity, with both expressions, was detected in EOP group. No absolute correlations between clinical parameters and betaG activity were observed, except for random correlations in the patient groups with mean total betaG activities. Also GCF/gingiva betaG levels and the 2 expressions did not show absolute correlations.

CONCLUSIONS

The findings of the present study confirm the relationship between betaG activity and periodontal diseases. The differences in data concerning GCF total betaG activity and betaG concentration may suggest that they are not matching measures. Data presentation seems to be an important factor in GCF/enzyme profile studies.

Relationship of the subgingival microbiota to a chairside test for aspartate aminotransferase in gingival crevicular fluid

BACKGROUND

The aim of the present study was to evaluate the association between the occurrence of certain specific periodontal pathogens and aspartate aminotransferase (AST) levels in gingival crevicular fluid (GCF).

METHODS

Thirty systemically healthy subjects with moderate to advanced periodontitis were selected. Within each subject, the AST contents of GCF from sites with probing depth between 5 mm and 7 mm were measured using a chairside colorimetric test. AST-positive site refers to one that had an AST level > or = 800 microIU. Subgingival plaque samples from one AST-positive and one negative site were collected for microbiological examination. One site with probing depth < or = 3 mm and no gingival inflammation was selected as a healthy control. Clinical parameters of the chosen sites, including the plaque index and gingival index scores, probing depth, and clinical attachment level were measured. Culture and immunofluorescence (IF) were used for detecting common periodontal pathogens, including Actinobacillus actinomycetemcomitans, Peptostreptococcus micros, Campylobacter rectus, Eikenella corrodens, Fusobacterium nucleatum, Capnocytophaga species, Prevotella intermedia, Prevotella melaninogenica, and Porphyromonas gingivalis. Logistic regression was used to analyze the correlation between the AST test and certain specific pathogens.

RESULTS

The GCF scores and total cultivable bacterial counts were higher in AST-positive sites than either AST-negative or healthy sites. The prevalence and proportions of specific periodontal pathogens such as C rectus, E. corrodens, F. nucleatum, Capnocytophaga species, P. intermedia, and P. gingivalis were significantly higher in positive than in negative sites. In analyzing the correlation of the proportion of 6 pathogens with the AST test by logistic regression, only P. gingivalis showed a significant positive correlation. The odds ratio of having a high proportion of P. gingivalis in the presence of a positive AST test was 1.21.

CONCLUSIONS

The present study showed that at AST-positive sites, there is a higher prevalence and higher proportion of certain periodontal pathogens. Although only the correlation of P. gingivalis and AST values was statistically significant, the results imply that certain periodontal pathogens may be associated with elevation of AST levels in GCF.

Analysis of gingival crevicular fluid intracytoplasmic enzyme activity in patients with adult periodontitis and rapidly progressive periodontitis. A longitudinal study model with periodontal treatment

In the present study, the activity of 3 functionally related enzymes, creatine kinase (CK), lactate dehydrogenase (LDH), and aspartate aminotransferase (AST) levels in the rest and flow gingival crevicular fluid (rGCF, fGCF) from patients with rapidly progressive periodontitis (RPP) and adult periodontitis (AP) were determined before and after periodontal treatment, including maintenance. When rGCF and fGCF mean enzyme levels were compared, rGCF was found to contain approximately twice as much enzyme levels than fGCF throughout the study. The findings of the present study revealed that both the rGCF and fGCF samples also contained higher CK, LDH, and AST levels than serum samples. Baseline clinical parameters and GCF enzyme levels presented a significant decline throughout the non-surgical and surgical treatment phases in both patient groups, with surgical treatment being more effective. Despite clinical stability, in the AP group levels of LDH and AST showed a tendency to increase in the third month, while enzyme levels still continued to decrease in the RPP group, who received additional antibiotics during the surgical phase. These findings suggest that GCF intracytoplasmic enzyme profile is related with periodontal status and successful periodontal treatment, in addition to clinical improvement, has a significant effect on this profile. Analysis of biochemical events, more specifically intracytoplasmic enzyme levels in GCF, are likely to offer a sensitive measure of periodontal pathology which may help in overcoming the existing limitations of clinical parameters. For this purpose, analysis of rGCF intracytoplasmic enzymes seems to be more beneficial.

Crevicular fluid level of beta-glucuronidase in relation to clinical periodontal parameters and putative periodontal pathogens in early-onset periodontitis

Analysis of beta-glucuronidase (betaG) in the gingival crevicular fluid (GCF) provides an indication of neutrophil influx into the crevicular environment. The aim of this study was to test the hypotheses that: (1) betaG is significantly elevated in individuals with early-onset periodontitis (EOP) and that betaG activity correlates with disease severity; and (2) betaG level may reflect the local bacterial challenge in the gingival crevice. The study subjects consisted of a sub-sample of individuals examined in the National Survey of Oral Health of United States Children, which was undertaken during the 1986/87 school year. A total of 249 individuals were selected based on presence or absence of clinical attachment loss at baseline. The individuals were examined a second time 6 years later and the clinical attachment loss was assessed, and subgingival plaque and GCF were collected. The subjects were classified into 3 types of EOP and a control group. BetaG activity in the GCF and the levels of 7 putative micro-organisms in the pocket were assessed. The generalized EOP group had the highest betaG activity, followed by the localized and incidental EOP groups, and the controls, respectively. There was a significant increase in betaG activity with the increase in probing depth. Also, sites with bleeding on probing had a significantly higher betaG activity than sites without bleeding. However, the effect of gingival inflammation on betaG activity was more evident in the generalized and localized EOP groups. Sites harboring high levels of one or more of the micro-organisms tended to have high betaG activity. There were moderate differences between the organisms with respect to their effect on betaG activity, but sites with high numbers of Porphyromonas gingivalis, Prevotella intermedia, or Treponema denticola also had the highest betaG activity. The present findings suggest that betaG activity in GCF from patients with EOP can be of value in the early identification of individuals at higher risk of developing EOP The findings also suggest that host mechanisms leading to higher betaG activity in EOP represent systemic responses and are only partly related to the presence of local factors at the site-level.

Evaluation of components of gingival crevicular fluid as diagnostic tests

Gingival crevicular fluid (GCF) is an inflammatory exudate that can be collected at the gingival margin or within the gingival crevice. The biochemical analysis of the fluid offers a noninvasive means of assessing the host response in periodontal disease. In recent years, the relationship of measures of the inflammatory response in GCF to risk for development of active periodontal disease (defined as clinical attachment loss or radiographic bone loss) has been studied in longitudinal trials. The greatest interest has focused on prostaglandin E2, an arachidonic acid metabolite; beta-glucuronidase and neutrophil elastase, markers of lysosomal enzyme release from neutrophils; and aspartate aminotransferase, a cytoplasmic enzyme indicative of cellular necrosis. Analysis of the data allows a number of conclusions to be drawn concerning the potential diagnostic significance of GCF: 1) an exuberant host inflammatory response is associated with progressive disease in patients with periodontitis; 2) collection of GCF using small precut strips is a reproducible and reliable collection technique; 3) the total amount of the mediator and not concentration of the mediator in the GCF sample can be reported when timed samples are collected; and 4) technology exists for GCF-based diagnostic tests to be performed in the dental office. Nevertheless, many questions remain. Still to be determined are: 1) the relationship of test results to the development of periodontitis in patients with gingivitis; 2) the level of test accuracy needed to justify use of these tests; 3) the unit of observation (patient, site) that is being evaluated by the test; and 4) the need for such tests as perceived by clinicians. While these questions are formidable, introduction of GCF-based diagnostic tests will provide clinicians with an improved, quantitative means of evaluating patients and offer specific criteria to assess the effectiveness of treatment.

Risk indicators for periodontal disease in a racially diverse urban population

A cross-sectional study of 117 subjects from a dental clinic serving a diverse population (i.e., Whites, African-Americans, Native-Americans, and Asians) was performed to evaluate risk indicators of periodontal disease. Gingival crevicular fluid (GCF) and subgingival plaque were taken at the same visit from 4 posterior sites of the most diseased sextant in each subject. Age, smoking packyears, beta-glucuronidase (beta G), neutrophil elastase (NE), myeloperoxidase (MPO), Fusobacterium nucleatum (F. nucleatum), and Porphyromonas gingivalis (P. gingivalis) were significantly (p < 0.05-0.005) correlated with attachment loss. Probing depth was significantly correlated with smoking packyears, beta G, NE, MPO, F. nucleatum and Prevotella intermedia (P. intermedia) (p < 0.05-0.005). Mean NE value of Whites was lower than the mean NE values of African-Americans, Native-Americans and Asians (p < 0.05). Whites had a lower mean beta G value compared to African Americans, and a lower mean MPO value compared to African Americans and Native Americans. The %s of patients positive for F. nucleatum, P. intermedia and Eikenella corrodens (E. corrodens) were higher in Native Americans compared to Whites. Step-wise multiple regression analysis was performed to construct models for the estimation of probing depth and attachment loss. The most parsimonious regression models which had the best R2 values included the following variables and accounted for the indicated % of variability: models 1 and 2: beta G, race, and F. nucleatum accounted for 50% of the variability in mean probing depth and 39% of the variability in a single site (first molar) for probing depth, respectively; model 3: age, beta G, and F. nucleatum accounted for 53% of the variability in mean attachment loss; model 4: age, NE, and F. nucleatum explained 35% of the variability in a single site (first molar) for attachment loss. The results suggest that age, race, smoking packyears, beta G, NE, MPO, F. nucleatum, P. gingivalis and P. intermedia are risk indicators for periodontal disease in this racially diverse urban population. Regression models which include multiple variables (i.e., demographic factors, GCF enzymes and periodontopathic bacteria) can be used to estimate periodontal disease status.

Current concepts in diagnosis and treatment of periodontitis

This article describes some areas of periodontal research and current opinions regarding detection of disease progression, as well as risk indicators and risk factors associated with disease progression. Longitudinal probing of periodontal attachment level is considered the gold standard for detection of disease activity although there are problems with this concept. Digital subtraction radiography can assist in the detection of minor changes of alveolar bone height and density. Risk factors such as composition of subgingival plaque and gingival crevicular fluid, as well as the effect of smoking are discussed. Adjunctive treatment with both antibiotics and nonsteroidal anti-inflammatory drugs, systemic or local, seems to be helpful in some forms of disease. Immunization to prevent colonization of tooth surfaces and pockets by periodontal pathogens does not seem to be feasible in the near future.

Host enzymes in gingival crevicular fluid as diagnostic indicators of periodontitis

Host responses to periodontal infections include the production of several families of enzymes that are released by stromal, epithelial or inflammatory cells. Study of these enzymes in gingival crevicular fluid may lead to insights into pathogenesis and may provide a rational basis for the development of novel diagnostic tests. However, analogous to other diagnostic interventions in dentistry and medicine, validation of host enzymes as diagnostic indicators is dependent on clear-cut demonstrations of the identity of the enzyme, reproducibility, diagnostic accuracy and clinical utility. The enzyme of interest should be readily measured over a broad range of disease severity and in varied clinical settings. Ideally, the enzyme should also be an essential component of proposed pathogenic mechanisms. In this context, the connective tissue matrix degrading enzymes elastase, collagenase and gelatinase are promising because of their apparently central role in periodontal attachment loss and disease progression. Sensitive and specific assays are also available to quantify these enzymes. Other work on enzymes associated with cell death (aspartate aminotransferase, lactate dehydrogenase) and several neutrophil lysosomal enzymes (beta glucuronidase, arylsulphatase, cathepsins) has demonstrated positive associations between enzyme levels and attachment loss and inflammation. While numerous cross-sectional studies have indicated that the levels of hydrolytic enzymes in gingival crevicular fluid parallel the severity of periodontal lesions, there are much less data on reproducibility, diagnostic accuracy and clinical utility in longitudinal studies. As appropriate study design is an essential prerequisite for establishing the efficacy of host enzymes as diagnostic tests, future clinical investigations should include: (1) individuals who would most likely benefit by early diagnosis, i.e., rapidly progressive and recurrent periodontitis cases; (2) longitudinal, cohort study designs to show that attachment loss is temporally linked with large increases in enzyme activity; (3) the use of a battery of tests to overcome intrinsic problems of low predictive values when prevalence of active disease is low. In the final analysis, the utility of host enzymes as diagnostic indicators will need to be examined in randomized controlled trials in which the question is asked: are patients better off as a result of testing?

Biochemical and histochemical analysis of the enzyme arylsulfatase in human lesions of endodontic origin

Lesions of endodontic origin are areas of inflammatory response which occur as a result of untreated disease process within the root canal system. Lysosomal hydrolytic arylsulfatase A and B have been identified as major enzymes initiating and propagating bone loss by degrading chondroitin-4-sulfate. The purpose of this investigation was to examine human lesions of endodontic origin for the presence of arylsulfatase A and B. Fifteen periapical lesions were obtained at the time of periapical surgery. The lesions were analyzed for the presence of arylsulfatases using the spectrophotometer by monitoring the liberated 4-nitrocatechol at 515-nm wavelength. The same lesions were examined histochemically using the electron microscope. Five control samples from healthy periodontal ligament were evaluated in a similar manner. The results showed higher levels of arylsulfatase A in lesions than in control tissues, and marked activity of arylsulfatase B in lesions, whereas no activity of this enzyme was detected in the control specimen. Histochemically, all lesions showed positive staining for enzyme activity, whereas the controls were negative. These findings indicate that arylsulfatase A and B play a role in the pathogenesis of human lesions of endodontic origin.

Host mediators in gingival crevicular fluid: implications for the pathogenesis of periodontal disease

During the past few years, a considerable number of studies have examined different aspects of the host response in gingival crevicular fluid (GCF), including the relationship of specific markers to the active phases of periodontal disease. Various indicators of the acute inflammatory response (the lysosomal enzymes beta-glucuronidase and collagenase, the cytoplasmic enzyme aspartate aminotransferase, and the arachidonic acid metabolite PGE2) have been shown to be associated with clinical attachment loss in chronic adult periodontitis in man and experimental periodontitis in animal models. In contrast, the relationship of indicators of the humoral immune response in GCF to active periodontal disease is equivocal. Furthermore, a number of indicators of the cellular immune response have been identified recently in GCF (i.e., Interleukin-1 alpha, IL-1 beta, tumor necrosis factor-alpha), but their relationship to active phases of periodontal disease have not been studied. The polymorphonuclear leukocyte (PMN) is the cellular hallmark of acute inflammation. Evidence from the GCF studies suggests that hyperreactivity of these cells plays a critical role in the active phases of some forms of periodontal disease. Metabolic activation of PMN can be associated with a number of potentially destructive reactions. The major effector mechanism for tissue destruction that can be specifically identified with the PMN is the synergistic effect of the release of PMN proteases and the generation of reactive oxygen metabolites by these cells. Priming of the PMN, where the PMN response is enhanced by agents that do not initiate the response, may be an important mechanism for PMN activation in the crevicular environment; for example, cytokines such as IL-1 beta and TNF-alpha, and lipopolysaccharides released from subgingival Gram-negative bacteria, can serve this function. The hypothesis proposed here argues that in addition to the severe forms of periodontal disease that have been associated with qualitative or quantitative PMN defects, tissue destruction in the periodontum can be observed with hyperreactivity of these cells. These differing conclusions do not create a dilemma, but may represent opposite ends of a balance that is no longer in equilibrium.

Repeated measurement of crevicular fluid parameters at different sites

Few systematic studies have been made of amounts or of the composition of gingival crevicular fluid (GCF) from different sites or of the stability of GCF parameters over time. These data are needed to better understand the relation of GCF composition to periodontal health status. This report gives the volume and the amounts of lactate dehydrogenase (LDH), aryl sulfatase (AS) and neutrophil elastase (NE) for GCF collected from 6 samplings of 6 standard gingival sites in 11 young adult subjects over a 6-week period. Attachment loss (3 mm) was noted at only 1 of the 66 sites. The mean gingival index of the 11 subjects ranged from 0.33 to 1.67. The GCF volume and activity/sample of LDH and AS but not NE differed among subjects. However, differences among subjects were not found when the GCF enzyme activities were expressed as activity/microliter GCF. GCF volume and LDH, AS and NE activity all differed among the 6 sites when the activities were expressed as either quantity/sample or microliter GCF. These data show that differences among sites must be carefully considered in evaluation of GCF data. Fluid volume and LDH, AS and NE activity all varied from sampling to sampling. However, differences among sites were retained throughout the experimental period.

Gingival crevicular fluid elastase-inhibitor complex: correlation with clinical indices and subgingival flora

This investigation analyzed, in a cross-sectional study, the possible relationship between gingival crevicular fluid (GCF) elastase-like protease (ELP) levels and the periodontal clinical parameters or the presence of specific bacteria in subgingival plaque. A total of 388 periodontal sites from 8 adult periodontitis patients were examined for plaque index (PII), gingival index (GI), pocket depth (PD) and alveolar bone loss (ABL). GCF ELP levels were determined as ELP alpha-1 protease inhibitor (ELP-alpha 1-PI) complex levels with a commercially available ELISA. Subgingival plaque samples were tested for the presence of Bacteroides gingivalis, B. intermedius and Actinobacillus actinomycetemcomitans by indirect immunofluorescence (IF) microscopy. GCF ELP-alpha 1-PI levels were then correlated with clinical periodontal indices and proportions of IF-positive bacteria per site. Statistically significant positive correlations were found between GCF ELP-alpha 1-PI concentrations and subgingival Bacteroides proportions. When the sites examined were analyzed depending on the level of each clinical parameter, the levels of these correlations changed. A. actinomycetemcomitans correlated highly (r = 0.716) with ABL for sites with low GI score. The correlations between GCF ELP-alpha 1-PI and B. gingivalis (r = 0.642) or B. intermedius (r = 0.774) were the highest for ABL less than or equal to 20% and PD less than or equal to 3 mm, respectively. The strong association between GCF ELP-alpha 1-PI concentrations and subgingival bacteria previously associated with advancing periodontitis indicates that measurement of GCF ELP-alpha 1-PI concentrations may be useful in the evaluation of periodontal sites, especially those with very little or no tissue destruction.

The relationship of serum IgG antibody titers to periodontal pathogens to indicators of the host response in crevicular fluid

In this study; the relationship of indicators of the local host response in gingival crevicular fluid (GCF) to the serum antibody titer to periodontal pathogens was examined. 15 patients with chronic adult periodontitis were studied. GCF was collected and analyzed for the total amount of IgG, IgM, the lysosomal enzyme B-glucuronidase (BG) and alpha-2-macroglobulin (alpha 2M). At the same examination, serum from these patients was collected, and enzyme-linked immunosorbent assays used to determine the serum IgG antibody titer to a panel of 17 periodontal pathogens (Actinobacillus actinomycetemcomitans (3 strains), Bacteroides gingivalis (4), Eikenella corrodens (2), Wolinella recta, Bacteroides intermedius (3), Fusobacterium nucleatum, and 3 Capnocytophaga species). Using Spearman rank order correlation analysis, correlation coefficients were calculated to relate the 4 indicators of host response in GCF to the serum IgG antibody titer to each of the 17 micro-organisms. The mean correlation between total IgG in GCF and the serum IgG antibody titer was positive (r = +0.30), and statistically significant correlations between total IgG in GCF and serum IgG antibody titer were observed for one strain of B. intermedius and C. ochracea. A weaker positive correlation was observed for IgM (r = 0.18). In contrast, the mean correlation between total BG in GCF and the serum antibody titer was negative (r = -0.34). Statistically significant negative correlations were observed for all 3 strains of A. actinomycetemcomitans, one strain of E. corrodens and W. recta. The mean correlation for alpha 2M was r = -0.06. These data suggest that elevated BG activity in GCF, believed to be a marker for lysosomal enzyme released from polymorphonuclear leukocytes in the crevicular environment, may be associated with a reduced serum IgG antibody response to suspected periodontal pathogens. Furthermore, these findings imply that the development of a serum IgG antibody response to suspected periodontal pathogens is consistent with a protective host response.

Role of cryptic receptors (cryptitopes) in bacterial adhesion to oral surfaces

Progress in characterizing the receptors that promote bacterial attachment to teeth and oral epithelial cells has suggested that hidden molecular segments may frequently be involved. Such cryptic receptors, referred to as 'cryptitopes', may become exposed by several mechanisms. Hidden segments of salivary acidic proline-rich proteins evidently become exposed when the molecules undergo a conformational change as they adsorb to apatitic mineral. Adhesins of Actinomyces viscosus and certain other prominent dental plaque bacteria are able to bind to these cryptitopes, and this enables these organisms to bind to proline-rich proteins on apatitic surfaces while avoiding interactions with these proteins in solution. Cryptitopes may also become exposed as a result of enzymatic action. Thus, several bacteria, including Fusobacterium nucleatum, Eikenella corrodens, A. viscosus, A. naeslundii and Bacteroides intermedius, have adhesins that bind to galactosyl receptors which become exposed after treatment with neuraminidase. Similarly, the adhesion of some Gram-negative bacteria, such as Bact. gingivalis, is enhanced when tissue surfaces are treated with certain proteases, or lysosomal enzymes derived from human polymorphonuclear leucocytes. It seems likely that elevated levels of enzymes present in gingival fluid as sequelae of poor oral hygiene and gingivitis may generate cryptitopes for potentially periodontopathic bacteria, and thereby contribute to modulation of the gingival flora.