Diagnosis of periodontal disease based on analysis of the host response

Effect of Interproximal Caries in Primary Molars on Clinical Parameters and Levels of Some Biochemical Markers in Gingival Crevicular Fluid

This study aims to investigate the relationship between dental caries and periodontal health by examining the clinical parameters and levels of some biochemical markers in the gingival crevicular fluid (GCF) of the teeth. In 22 children, 22 maxillary primary canine teeth and a pair of primary molars in a total of 38 quadrants were examined. The control group (C) consisted of children who had at least 1 caries-free primary maxillary canine. The test group (T) consisted of children who had a pair of primary molars where the interproximal contact was lost due to the caries in the same quadrant. Their primary molars were restored with compomer. The teeth were evaluated based on clinical values (plaque index, gingival index, and probing depth) and biochemical values in GCF before (C₀, T₀) and after a 6-month treatment (C₁, T₁). While total amounts of interleukin-1 beta and vascular endothelial growth factor in GCF in T₀ were significantly higher than in C₀ (P < 0.001), osteocalcin was statistically insignificant (P > 0.05). Clinic parameters in T₀ were significantly higher than in C₀ and T₁. Also these parameters in C₀ were higher than in C₁ (P < 0.01). Clinical and biochemical parameters in GCF in the teeth with interproximal caries might show symptoms of periodontitis.

Developing a periodontal disease antibody array for the prediction of severe periodontal disease using machine learning classifiers

BACKGROUND

The aim of this study was to simultaneously and quantitatively assess the expression levels of 20 periodontal disease-related proteins in gingival crevicular fluid (GCF) from normal controls (NOR) and severe periodontitis (SP) patients with an antibody array.

METHODS

Antibodies against 20 periodontal disease-related proteins were spotted onto a glass slide to create a periodontal disease antibody array (PDD). The array was then incubated with GCF samples collected from 25 NOR and 25 SP patients. Differentially expressed proteins between NOR and SP patients were then used to build receiver operator characteristic (ROC) curves and compare five classification models, including support vector machine, random forest, k nearest neighbor, linear discriminant analysis, and Classification and Regression Trees.

RESULTS

Seven proteins (C-reactive protein, interleukin [IL]-1α, interleukin-1β, interleukin-8, matrix metalloproteinase-13, osteoprotegerin, and osteoactivin) were significantly upregulated in SP patients compared with NOR, while receptor activator of nuclear factor-kappa was significantly downregulated. The highest diagnostic accuracy using a ROC curve was observed for IL-1β with an area under the curve of 0.984. Five of the proteins (IL-1β, IL-8, MMP-13, osteoprotegerin, and osteoactivin) were identified as important features for classification. Linear discriminant analysis had the highest classification accuracy across the five classification models that were tested.

CONCLUSION

This study highlights the potential of antibody arrays to diagnose periodontal disease.

Total Antioxidant Capacity and Total Oxidant Status in Saliva of Periodontitis Patients in Relation to Bacterial Load

The detection of salivary biomarkers has a potential application in early diagnosis and monitoring of periodontal inflammation. However, searching sensitive salivary biomarkers for periodontitis is still ongoing. Oxidative stress is supposed to play an important role in periodontitis progression and tissue destruction. In this cross-sectional study, we investigated total antioxidant capacity (TAC) and total oxidant status (TOS) in saliva of periodontitis patients compared to healthy controls and their relationship with periodontopathic bacteria and periodontal disease severity. Unstimulated saliva was collected from 45 patients with generalized severe periodontitis and 37 healthy individuals and the TAC/TOS were measured. In addition, salivary levels of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Fusobacterium nucleatum in saliva were measured. Salivary TAC was lower in periodontitis patients compared to healthy controls. Moreover, a significant negative correlation of salivary TAC with clinical attachment loss was observed in periodontitis patients. No significant difference in the salivary TOS was observed between periodontitis patients and healthy controls. Bacterial load was enhanced in periodontitis patients and exhibited correlation with periodontal disease severity but not with salivary TAC/TOS. Our data suggest that changes in antioxidant capacity in periodontitis patients are not associated with increased bacterial load and are probably due to a dysregulated immune response.

Evaluation of Salivary Levels of Pyridinoline Cross Linked Carboxyterminal Telopeptide of Type I Collagen (ICTP) in Periodontal Health and Disease

BACKGROUND

Traditional parameters (Pocket depth, bleeding on probing, clinical attachment loss, radiographic findings) have been used for a long time for the assessment of periodontal disease conditions. However, these parameters only indicate towards the periodontal damage that has already taken place but do not give any idea regarding the current status of the periodontal health or disease. Hence, the present study is aimed at evaluating the concentration of the bone biomarker ICTP in saliva, which can give a better real time assessment of periodontal health and disease.

MATERIALS AND METHODS

Forty three patients were selected and divided into three groups based on the recorded clinical parameters of probing pocket depth, attachment loss and bleeding on probing. Group I (Healthy, n = 11), Group II (Gingivitis, n = 17), Group III (Periodontitis. n = 15). Salivary samples were collected before scaling and root planning to avoid contamination by blood. ICTP levels were evaluated in the salivary samples by using enzyme linked immunosorbent assay (ELISA).

STATISTICAL ANALYSIS USED

Kruskal Wallis test was used to compare the mean ICTP level of the three groups.

RESULTS

ICTP was detected in all the samples. Highest mean ICTP concentrations in saliva were obtained for group III (periodontitis group) and the lowest mean ICTP concentrations were seen in group I (healthy group). This suggests that the level of ICTP in saliva increases proportionally from periodontal health to diseased conditions (gingivitis & periodontitis).

CONCLUSION

There is a substantial increase in the salivary concentration of ICTP in chronic periodontitis patients than in gingivitis and healthy patients. Salivary ICTP levels were the maximum in chronic periodontitis patients followed by gingivitis patients and the least in healthy individuals. ICTP may be considered as a biomarker in periodontal disease progression.

To estimate salivary aspartate aminotransferase levels in chronic gingivitis and chronic periodontitis patients prior to and following non-surgical periodontal therapy: A clinico-biochemical study

Context:

Saliva can be used as a diagnostic fluid in dentistry. Various enzymes have been proposed as markers for periodontal destruction. One of them is aspartate aminotransferase, for which salivary analysis can offer a cost-effective approach for monitoring the disease. Changes in enzymatic activity reflect metabolic changes in the gingiva and periodontium in inflammation.

Aims:

The purpose of this study was to assess the aspartate aminotransferase levels in saliva prior to and following scaling and root planning (SRP) at 1 month and 3 month interval and correlating it with the clinical parameters in generalized chronic gingivitis and chronic periodontitis patients.

Materials and Methods:

Thirty patients with generalized chronic gingivitis and 30 with generalized chronic periodontitis were selected. The activity of aspartate aminotransferase levels in saliva were assessed biochemically before and after SRP at 1 month and 3 months. The aspartate aminotransferase levels were correlated with clinical parameters (gingival index and probing depth).

Statistical Analysis Used:

A paired t test was done.

Results:

A decrease in gingival index, probing depth, and aspartate aminotransferase levels were seen in both the groups at 1 and 3 months which was found to be statistically highly significant (P value 0.00). Aspartate aminotransferase levels were statistically significantly correlated with the clinical parameters at baseline (P < 0.05) but at 3 months, a positive correlation was seen in both the groups which was statistically insignificant (P > 0.05).

Conclusions:

Elevated salivary aspartate aminotransferase levels were seen in generalized chronic gingivitis and chronic periodontitis patients, with higher values recorded in generalized chronic periodontitis correlating to the tissue destruction taking place in these conditions.

In vitro effects of bisphosphonates on chemotaxis, phagocytosis, and oxidative burst of neutrophil granulocytes

OBJECTIVES

Bisphosphonate-associated osteonecrosis of the jaws is a serious side effect that mainly occurs in patients receiving highly potent, nitrogen-containing bisphosphonates. Usually the diagnosis is made due to exposed bone and a nonhealing wound. Neutrophil granulocytes are essential for sufficient wound healing; therefore, the influence of different bisphosphonates on neutrophil granulocytes was the focus of this study.

MATERIAL AND METHODS

The effect of nitrogen-containing bisphosphonates (ibandronate, pamidronate, and zoledronate) and one non-nitrogen-containing bisphosphonate (clodronate) on chemotaxis, phagocytosis, and oxidative burst of neutrophil granulocytes in human whole blood was analyzed using standard cytometric flow assays.

RESULTS

Chemotaxis of neutrophils was reduced by almost 50 % when cells were treated with ibandronate and zoledronate. All tested nitrogen-containing bisphosphonates moderately increased the percentage of phagocytizing neutrophils, whereas the percentage of oxidizing cells was extremely affected. Zoledronate increased the oxidative burst activity even at low concentrations. Treatment with ibandronate and pamidronate reached the same level, but only in at least 10 times the higher concentrations. The maximal burst activity of a single cell reached nearly 150 % compared to control. In this case, zoledronate also caused maximal effects even at low concentrations. Clodronate did not show any effects.

CONCLUSION

The results show a proinflammatory effect of the nitrogen-containing effect on neutrophil granulocytes which might contribute to the development of osteonecrosis.

CLINICAL RELEVANCE

The altered neutrophil defense might play a key role in the pathogenesis of bisphosphonate-associated osteonecrosis of the jaws, although the underlying causation between inflammatory reaction and the development of necrosis is yet unknown.

Effect of local application of tea tree (Melaleuca alternifolia) oil gel on long pentraxin level used as an adjunctive treatment of chronic periodontitis: A randomized controlled clinical study

Background:

Conventional non-surgical periodontal therapy has been proven to be an effective treatment for patients with chronic periodontitis. Tea tree oil (TTO) can be used as adjunct to conventional periodontal therapy in patient with chronic periodontitis. The aim of this study was to evaluate the effectiveness of adjunctive treatment of TTO on the clinical parameters and the level of pentraxin-3 (PTX3) in chronic periodontitis.

Materials and Methods:

A total of 40 patients with moderate to severe chronic periodontitis were divided into two groups, Group I received scaling and root planing (SRP) only, Group II received SRP and TTO gel. Clinical parameters were recorded and gingival crevicular fluid (GCF) samples were collected from each subject for measuring PTX3 levels at baseline, 1, 3 and 6 months after treatment.

Results:

In all evaluation periods, there was statistically significant reduction in each of the studied clinical parameters and PTX3 level in Group II as compared with Group I.

Conclusions:

The local delivery of TTO gel in case of chronic periodontitis may have some beneficial effects to augment the results of the conventional periodontal therapy. Moreover, it places a focus on the value of monitoring GCF levels of PTX3 as a marker of periodontal tissue healing.

Intracytoplasmic enzymes in gingival crevicular fluid of patients with aggressive periodontitis

BACKGROUND AND OBJECTIVE

Biochemical parameters of crevicular fluid could provide evidence of periodontal tissue disease. The aim of this study was to analyze enzymes in crevicular fluid in aggressive localized and generalized periodontitis.

MATERIAL AND METHODS

One hundred and twenty-four subjects were classified as having localized (n = 36) or generalized aggressive periodontitis (n = 38) and subclassified into moderate and severe groups. Controls were 50 periodontitis-free subjects. Activities of the enzymes lactate dehydrogenase, neutrophil elastase, alkaline phosphatase and aspartate aminotransferase were determined. Data were analyzed using one-way ANOVA and Tukey's test.

RESULTS

Among the subjects with localized aggressive periodontitis, values of lactate dehydrogenase and alkaline phosphatase increased notably in moderate and severe periodontitis compared with control subjects. Values for aspartate aminotransferase increased with the severity of the disease, and neutrophil elastase was increased in the moderate and severe states. In generalized aggressive periodontitis, lactate dehydrogenase showed higher values than in control subjects in both periodontal subgroups. Alkaline phosphatase and neutrophil elastase showed higher significant differences between moderate and severe periodontitis compared with the control group. Aspartate aminotransferase showed differences between the severe and moderate periodontitis groups compared with the control group. Of all the enzymes analyzed, only lactate dehydrogenase showed higher values in localized than in generalized aggressive periodontitis.

CONCLUSION

Lactate dehydrogenase may distinguish localized and generalized aggressive periodontitis. Alkaline phosphatase increases from moderate to severe states in both types of periodontitis. Aspartate aminotransferase and neutrophil elastase only increase with strong evidence of periodontal destruction.

Salivary interleukin-1β levels in patients with chronic periodontitis before and after periodontal phase I therapy and healthy controls: a case-control study

BACKGROUND

The role of interleukin (IL)-1β in periodontal disease pathogenesis is well researched. This study aimed to assess and compare the salivary IL-1β levels in patients with chronic periodontitis before and after periodontal phase I therapy and periodontally healthy controls. Further, relationships between IL-1β levels and various clinical parameters were explored.

METHODS

Twenty-eight patients with moderate-to-severe generalized chronic periodontitis and 24 age-, race-, and ethnicity-matched controls participated in this study. Saliva samples were obtained from all patients. The clinical parameters recorded were clinical attachment loss (AL), probing depth, bleeding on probing, periodontal index, and gingival index. Clinical evaluation and sample collection were repeated 1 month after periodontal phase I therapy in patients with periodontitis. IL-1β levels were assessed using enzyme-linked immunosorbent assay.

RESULTS

Mean IL-1β levels in patients with periodontitis at baseline (1,312.75 pg/mL) were significantly higher (P <0.0001; eight-fold) than in controls (161.51 pg/mL). Although treatment in patients with periodontitis resulted in significant reduction in IL-1β levels (mean: 674.34 pg/mL; P = 0.001), they remained significantly higher (P <0.0001; four-fold) than control levels. There were significant correlations between IL-1β levels and all clinical parameters (P <0.01) except percentage sites with clinical AL >2 mm (P >0.05).

CONCLUSIONS

The data indicate that IL-1β levels are raised in the saliva of patients with chronic periodontitis, which are reduced after phase I therapy, suggesting a close association between salivary IL-1β and periodontitis. Additional longitudinal studies are needed to validate salivary IL-1β as a marker for periodontal disease.

Current developments in salivary diagnostics

Salivary diagnostics is an emerging field that has progressed through several important developments in the past decade, including the publication of the human salivary proteome and the infusion of federal funds to integrate nanotechnologies and microfluidic engineering concepts into developing compact point-of-care devices for rapid analysis of this secretion. In this article, we discuss some of these developments and their relevance to the prognosis, diagnosis and management of periodontitis, as an oral target, and cardiovascular disease, as a systemic example for the potential of these biodiagnostics. Our findings suggest that several biomarkers are associated with distinct biological stages of these diseases and demonstrate promise as practical biomarkers in identifying and managing periodontal disease, and acute myocardial infarction. The majority of these studies have progressed through biomarker discovery, with the identified molecules requiring more robust clinical studies to enable substantive validation for disease diagnosis. It is predicted that with continued advances in this field the use of a combination of biomarkers in multiplex panels is likely to yield accurate screening tools for these diagnoses in the near future.

Involvement of Toll-like receptors 2 and 4 in the innate immune response to Treponema denticola and its outer sheath components

Treponema denticola is considered an important oral pathogen in the development and progression of periodontal diseases. In the present study, the mechanisms of recognition and activation of murine macrophages by T. denticola and its major outer sheath protein (MSP) and lipooligosaccharide (LOS or glycolipid) were investigated. T. denticola cells and the MSP induced innate immune responses through TLR2-MyD88, whereas LOS induced a macrophage response through TLR4-MyD88. The presence of gamma interferon (IFN-gamma), or of high numbers of T. denticola, circumvented the requirement for TLR2 for the macrophage response to T. denticola, although the response was still dependent on MyD88. In contrast, synergy with IFN-gamma did not alter the TLR dependence of the response to the T. denticola surface components LOS and MSP, despite enhanced sensitivity. These data suggest that although there is flexibility in the requirements for recognition of T. denticola cells (TLR2 dependent or independent), MyD88 is a requirement for the downstream signaling events that lead to inflammation. We also demonstrate that both outer sheath molecules LOS and MSP induce macrophage tolerance to further stimulation with enterobacterial lipopolysaccharide. Tolerance induced by T. denticola components during mixed infections may represent a general mechanism through which bacteria evade clearance.

Salivary cytokine levels in subjects with chronic periodontitis and in periodontally healthy individuals: a cross-sectional study

BACKGROUND AND OBJECTIVE

Saliva has been proposed as a noninvasive diagnostic fluid that could be used in the diagnosis of oral and systemic diseases. The levels of salivary biomarkers, such as cytokines, could potentially be used as a surrogate to distinguish periodontally healthy individuals from subjects with periodontitis. Therefore, the goal of the present investigation was to determine if the levels of 10 different cytokines in saliva differed between a group of periodontally healthy individuals and a group of subjects with periodontitis. Correlations between the concentrations of these 10 cytokines and clinical parameters of periodontal disease were also examined.

MATERIAL AND METHODS

In this cross-sectional study, 74 subjects with chronic periodontitis and 44 periodontally healthy individuals were periodontally examined and had the levels of granulocyte-macrophage colony-stimulating factor, interleukin-1beta, interleukin-2, interleukin-4, interleukin-5, interleukin-6, interleukin-8, interleukin-10, interferon-gamma and tumor necrosis factor-alpha measured in whole saliva using a multiplexed bead immunoassay (Luminex). Significance of statistical differences in the levels of salivary cytokines between groups was determined using nonparametric analysis of covariance, adjusting for age and smoking status. The Spearman rank correlation coefficient was used to explore associations between the mean levels of salivary cytokines and mean clinical parameters.

RESULTS

There were no statistically significant differences between groups for any of the cytokines. There were weak, statistically significant positive associations between salivary interleukin-8 and pocket depth (r(s) = 0.2, p < 0.05) and bleeding on probing (r(s) = 0.2, p < 0.05), and weak negative correlations between salivary interleukin-10 and attachment level (r(s) = -0.2, p < 0.05) and bleeding on probing (r(s) = -0.3, p < 0.001).

CONCLUSION

Mean salivary levels of granulocyte-macrophage colony-stimulating factor, interleukin-1beta, interleukin-2, interleukin-4, interleukin-5, interleukin-6, interleukin-8, interleukin-10, interferon-gamma and tumor necrosis factor-alpha could not discriminate between periodontal health and disease.

Bone remodeling biomarkers of periodontal disease in saliva

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha), C-telopeptide pyridinoline cross-links of type I collagen (ICTP), and receptor activator of nuclear factor-kappa B ligand (RANKL) have been associated with bone remodeling and periodontal tissue destruction. This study evaluated the level of these biomarkers in saliva with respect to periodontal disease status.

METHODS

Levels of TNF-alpha in unstimulated whole saliva of 74 adults (35 subjects with moderate to severe periodontal disease and 39 healthy controls) and salivary levels of RANKL and ICTP of a subset of 21 subjects and 21 matched controls were examined using enzyme immunosorbent assays in a case-control clinical study.

RESULTS

Salivary levels of TNF-alpha were detected in all subjects, whereas levels of ICTP and RANKL were detected in only a minority of subjects. Mean salivary levels of TNF-alpha were significantly higher in individuals with periodontal disease (mean: 4.33 pg/ml) than in controls (mean: 2.03 pg/ml; P = 0.02), with a maximum level (27.96 pg/ml) observed in periodontitis. Subjects with salivary TNF-alpha levels above a threshold of 5.75 pg/ml (i.e., two standard deviations above the mean of the controls) had significantly more sites with bleeding on probing, probing depths >/=4 mm, and attachment loss > or =2 mm (P < or =0.01).

CONCLUSION

Salivary levels of TNF-alpha were elevated in patients who had clinical indicators of periodontitis, suggesting that this biomarker may serve in a panel of salivary biomarkers that could facilitate the screening, diagnosis, and management of periodontal disease.

Acute stress induces proinflammatory signaling at chronic inflammation sites

OBJECTIVES

To analyze in a randomized controlled study whether acute psychological stress alters local proinflammatory signals in a human model of chronic inflammation, i.e., gingivitis. Chronic inflammation represents a crucial factor in a variety of diseases and factors that contribute to the onset and progression of disease. Psychological stress is assumed to represent such a factor. However, experimental human research in this area is rare.

METHODS

A total of 25 students (n = 11 females, 14 males) suffering from gingivitis were subjected to a stress (public-speaking task) and to a control condition in randomized order. Local concentrations of interleukin (IL)-8 were quantified as an indicator of proinflammatory activity at sites of inflammation. IL-8 is a strong proinflammatory mediator and involved in a variety of disease processes. Samples were taken at sites of inflammation before stress versus control condition and 0, 45, and 90 minutes afterward.

RESULTS

A significant main effect (p = .03) of acute stress on local IL-8 was found. Stress induced an increase of IL-8-concentrations; univariate effect sizes varied between d = 0.23 and d = 0.36.

CONCLUSION

This is the first human experimental in vivo study demonstrating that psychological stress alters the local concentrations of IL-8 under conditions of chronic inflammation. It provides direct evidence acute stress is involved in the regulation of local proinflammatory responses in chronic inflammation. Future studies should now explore the effects of more enduring stress conditions and the factors mediating stress effects on inflammatory signals.

Oral fluid-based biomarkers of alveolar bone loss in periodontitis

Periodontal disease is a bacteria-induced chronic inflammatory disease affecting the soft and hard supporting structures encompassing the teeth. When left untreated, the ultimate outcome is alveolar bone loss and exfoliation of the involved teeth. Traditional periodontal diagnostic methods include assessment of clinical parameters and radiographs. Though efficient, these conventional techniques are inherently limited in that only a historical perspective, not current appraisal, of disease status can be determined. Advances in the use of oral fluids as possible biological samples for objective measures of current disease state, treatment monitoring, and prognostic indicators have boosted saliva and other oral-based fluids to the forefront of technology. Oral fluids contain locally and systemically derived mediators of periodontal disease, including microbial, host-response, and bone-specific resorptive markers. Although most biomarkers in oral fluids represent inflammatory mediators, several specific collagen degradation and bone turnover-related molecules have emerged as possible measures of periodontal disease activity. Pyridinoline cross-linked carboxyterminal telopeptide (ICTP), for example, has been highly correlated with clinical features of the disease and decreases in response to intervention therapies, and has been shown to possess predictive properties for possible future disease activity. One foreseeable benefit of an oral fluid-based periodontal diagnostic would be identification of highly susceptible individuals prior to overt disease. Timely detection and diagnosis of disease may significantly affect the clinical management of periodontal patients by offering earlier, less invasive, and more cost-effective treatment therapies.

Salivary biomarkers of existing periodontal disease: a cross-sectional study

BACKGROUND

The authors conducted a study to determine if salivary biomarkers specific for three aspects of periodontitis--inflammation, collagen degradation and bone turnover--correlate with clinica features of periodontal disease.

METHODS

The relationship between periodontal disease and the levels of interleukin-1 beta (IL-1beta), matrix metalloproteinase (MMP)-8, and osteoprotegerin (OPG) in whole saliva of 57 adults (28 "case" subjects with moderate-to-severe periodontal disease and 29 healthy control subjects) was examined in a case-control trial.

RESULTS

Mean levels of IL-1beta and MMP-8 in saliva were significantly higher in case subjects than in controls. Both analytes correlated with periodontal indexes, whereas, after adjustment for confounders, OPG did not. Elevated salivary levels of MMP-8 or IL-1beta (more than two standard deviations above the mean of the controls) significantly increased the risk of periodontal disease (odds ratios in the 11.3-15.4 range). Combined elevated salivary levels of MMP-8 and IL-1beta increased the risk of experiencing periodontal disease 45-fold, and elevations in all three biomarkers correlated with individual clinical parameters indicative of periodontal disease.

CONCLUSION

Salivary levels of MMP-8 and IL-1beta appear to serve as biomarkers of periodontitis.

CLINICAL IMPLICATIONS

Qualitative changes in the composition of salivary biomarkers could have significance in the diagnosis and treatment of periodontal disease.

Profiling the Cytokines in Gingival Crevicular Fluid Using a Cytokine Antibody Array

BACKGROUND

Various compounds have been detected in gingival crevicular fluid (GCF) as indicators of periodontal disease activity. Therefore, the analysis of GCF may be especially beneficial for diagnosing current periodontal status and addressing the effects of treatment. Moreover, the identification of new markers in GCF may also contribute to elucidating novel mechanisms involved in periodontal disease. This study sought novel marker proteins specific to chronic periodontitis by profiling cytokines in GCF using a cytokine antibody array system.

METHODS

Human cytokine array V, which detects 79 cytokines on one membrane, was used to determine the profile of cytokines in GCF from seven subjects with chronic periodontitis and seven subjects with healthy periodontia. The profile was exposed to x-ray film and quantified using image analysis software. Healthy and diseased sites were compared statistically.

RESULTS

We detected 10 cytokines in periodontally healthy sites and 36 cytokines in periodontally diseased sites. Interleukin-8 (IL-8) and transforming growth factor-beta 2 (TGF-beta2) were detected at high levels in healthy and diseased subjects. There were significant differences between healthy and diseased subjects in the levels of tissue inhibitor of metalloproteinases-2 (TIMP-2), tumor necrosis factor-beta (TNF-beta), growth-related oncogene (GRO), interferon-inducible protein-10 (IP-10), angiogenin (Ang), vascular endothelial growth factor (VEGF), insulin-like growth factor binding protein-3 (IGFBP-3), osteoprotegerin (OPG), epidermal growth factor (EGF), glial-derived neurotrophic factor (GDNF), pulmonary and activation-regulated chemokine (PARC), oncostatin M (OSM), fibroblast growth factor-4 (FGF-4), IL-16, homologous to lymphotoxins (LIGHT), and placenta growth factor (PlGF). Of these, the newly detected cytokines were GRO, Ang, IGFBP-3, GDNF, PARC, OSM, FGF-4, IL-16, LIGHT, and PlGF.

CONCLUSIONS

In this study, we detected several cytokines in GCF using a cytokine antibody array system, including both inflammatory cytokines and various growth factors. Therefore, periodontal disease may participate in the wound healing process and in tissue destruction via the inflammatory process. Our results suggest that the quantification of these cytokines in GCF provides useful information for the diagnosis of periodontal disease status.

Diagnostic biomarkers for oral and periodontal diseases

This article provides an overview of periodontal disease diagnosis that uses clinical parameters and biomarkers of the disease process.This article discusses the use of biomarkers of disease that can be identified at the tissue, cellular, and molecular levels and that are measurable in oral fluids such as saliva and gingival crevicular fluid. Biomarkers identified from these biologic fluids include microbial, host response, and connective tissue-related molecules that can target specific pathways of local alveolar bone resorption. Future prospects for oral fluid-based diagnostics that use micro-array and microfluidic technologies are presented.

A marker of oxidative stress in saliva: association with periodontally-involved teeth of a hopeless prognosis

The aim of this study was to determine the association between levels of a marker of oxidative stress, 8-hydroxydeoxyguanosine (8-OHdG), in saliva and the presence of teeth with a hopeless prognosis as a result of advanced periodontitis. Thirty-four periodontitis patients were divided into two groups based on the presence or absence of periodontally-involved teeth of hopeless prognosis. Salivary levels of 8-OHdG in those with were significantly higher than in subjects without periodontally-involved teeth of hopeless prognosis (4.78 +/- 0.14 ng/ml and 2.35 +/- 0.18 ng/ml, respectively). We also evaluated 8-OHdG levels in gingival crevicular fluid (GCF) of teeth with advanced periodontal destruction (mean probing depth = 7.2). In this case, 8-OHdG was detected only from those periodontally-involved teeth of hopeless prognosis, and only in some cases (8 out of 18 samples). These data suggest that periodontally-involved teeth of hopeless prognosis are a major source of salivary 8-OHdG. Measurement of salivary 8-OHdG levels may prove to be useful in identifying patients with teeth of hopeless prognosis.

PMN responses in chronic periodontal disease: evaluation by gingival crevicular fluid enzymes and elastase-alpha-1-proteinase inhibitor complex

OBJECTIVES

In the present trial, the hypothesis was examined that the local PMN responses in untreated and treated chronic periodontitis can be differentiated by gingival crevicular fluid lysosomal enzyme activities and elastase-alpha-1-proteinase inhibitor complex.

METHODS

In nine subjects (average age 49.2 +/- 7.1 years) with chronic periodontitis, clinical parameters and markers of the PMN-derived inflammatory tissue response in gingival crevicular fluid (GCF) were assessed before and 6 months after surgical periodontal therapy. Myeloperoxidase (MPO), beta-N-acetyl-hexosaminidase (beta-NAH) and cathepsin D (CD) were analyzed as indicators of the PMN-associated host tissue destruction, and elastase-alpha-1-proteinase inhibitor complex (alpha-1-EPI) as the major serum protein inactivating PMN elastase. The total activities of the lysosomal enzymes MPO and beta-NAH were evaluated spectrophotometrically, the CD levels by liquid scintillation counting with [14C] hemoglobin as substrate, and the total alpha-1-proteinase inhibitor complex using a sandwich-immunoassay.

RESULTS

The clinical parameters revealed a statistical significant decrease at the 6-month reexamination. PD levels dropped from 5.40 to 2.88 mm (change 2.52 +/- 1.04 mm), the CAL scores from 6.67 to 4.43 mm (change 2.24 +/- 0.77 mm). The 30 s GCF volumes dropped from 129.8 to 68.6, displaying a change of 61.1 +/- 18.6, p </= 0.05. The decrease in total MPO, beta-NAH and CD levels (medians: 1.7/0.6 micro U MPO, 0.035/0.020 micro U beta-NAH, 1.3/0.5 ng CD) following therapy was associated with a significant drop in total GCF amounts of alpha-1-EPI from 76.3 ng at baseline to 52.4 ng after 6 months.

CONCLUSION

The clinical healing in chronic periodontal disease is associated with a downregulation of the local PMN responses following periodontal therapy. The reorganization of periodontal tissues is characterized by a decrease of lysosomal enzyme activities and the alpha-1-proteinase inhibitor complex in gingival crevicular fluid.

Periodontal risk assessment, diagnosis and treatment planning

The prevention and treatment of the periodontal diseases is based on accurate diagnosis, reduction or elimination of causative agents, risk management and correction of the harmful effects of disease. Prominent and confirmed risk factors or risk predictors for periodontitis in adults include smoking, diabetes, race, P. gingivalis, P. intermedia, low education, infrequent dental attendance and genetic influences. Several other specific periodontal bacteria, herpesviruses, increased age, male, sex, depression, race, traumatic occlusion and female osteoporosis in the presence of heavy dental calculus have been shown to be associated with loss of periodontal support and can be considered to be risk indicators of periodontitis. The presence of furcation involvement, tooth mobility, and a parafunctional habit without the use of a biteguard are associated with a poorer periodontal prognosis following periodontal therapy. An accurate diagnosis can only be made by a thorough evaluation of data that have been systematically collected by: 1) patient interview, 2) medical consultation as indicated, 3) clinical periodontal examination, 4) radiographic examination, and 5) laboratory tests as needed. Clinical signs of periodontal disease such as pocket depth, loss of clinical attachment and bone loss are cumulative measures of past disease. They do not provide the dentist with a current assessment of disease activity. In an attempt to improve the ability to predict future disease progression, several types of diagnostic tests have been studied, including host inflammatory products and mediators, enzymes, tissue breakdown products and subgingival temperature. In general, the usefulness of these tests for predicting future disease activity remains to be established in terms of sensitivity, specificity and predictive value. Although microbiological analysis of subgingival plaque is not necessary to diagnose and treat most patients with periodontitis, it is helpful when treating patients with unusual forms of periodontal disease such as early-onset, refractory and rapidly progressive disease. There appears to be a strong genetic component in some types of periodontal disease and genetic testing for disease susceptibility has potential for future use, but more research is needed to determine its utility for use in clinical practice. Treatment of the periodontal diseases may be divided into four phases: systemic, hygienic, corrective and maintenance or supportive periodontal therapy. Regardless of the type of treatment provided, periodontal therapy will fail or will be less effective in the absence of adequate supportive periodontal therapy.

The effects of periodontal therapy on intracrevicular prostaglandin E2 concentrations and clinical parameters in pregnancy

BACKGROUND

The increase in circulating levels of progesterone during pregnancy stimulates production of prostaglandins, especially prostaglandin E2, possibly resulting in pregnancy gingivitis. The purpose of this study is to evaluate the influence of prostaglandin E2 concentrations on gingival tissues in pregnancy and to assess its relationship to clinical parameters.

METHODS

This study evaluates the effects of periodontal treatment on clinical indices including plaque index, gingival index, probing depth, and gingival crevicular fluid prostaglandin E2 levels of 22 pregnant women in their first, second, and third trimesters. Initial periodontal therapy consisting of scaling, root planing, and oral hygiene instruction was performed at the beginning of the first trimester and repeated each trimester. Prostaglandin E2 concentrations in gingival crevicular fluid were determined using a commercially available enzyme immunoassay kit. The statistical tests used were paired sample test and correlation analysis.

RESULTS

The results of the study show that periodontal therapy has resulted in an improvement in clinical parameters (P<0.05). There is also a statistically significant decrease in levels of prostaglandin E2 at the second and third trimesters following periodontal therapy (P <0.001). The correlation between prostaglandin E2 concentrations and clinical parameters is found to be non-significant (P >0.05).

CONCLUSIONS

Our data indicate that levels of prostaglandin E2 in gingival crevicular fluid may be used as a marker of gingival inflammation in order to determine the effects of periodontal therapy in pregnancy. Periodontal therapy that is performed throughout the entire pregnancy period may help prevent the threat of pregnancy gingivitis.

Association of early onset periodontitis microbiota with aspartate aminotransferase activity in gingival crevicular fluid

OBJECTIVES

The objective of this study was to determine the relationship between the activity of the enzyme aspartate aminotransferase (AST) in gingival crevicular fluid (GCF) using the colorimetric PerioGard (PTM) test and the subgingival microflora in early onset periodontitis lesions.

MATERIAL AND METHODS

The study population consisted of 25 otherwise healthy individuals exhibiting early onset periodontitis (EOP). In each patient four experimental sites were identified comprising one deep periodontal pocket (PD >5 mm) randomly chosen in each quadrant. Bacterial samples were obtained from the experimental sites, consecutively cultured anaerobically and in 10% CO(2) using selective and nonselective media. Isolates were characterized to species level by conventional biochemical tests and various identification kits. Clinical measurements as well as AST activity, assessed either as positive or negative using the PTM, were recorded at the same sites.

RESULTS

Sixty-two sites exhibited AST positive and 38 AST negative activity. Analysis of bacterial counts using the ANOVA (Mann Whitney U-test) showed that Streptococcus intermedius, Peptostreptococcus micros, Campylobacter concisus, Bacteroides forsythus, Camplobacter gracilis, Campylobacter rectus and Selenomonas sputigena were significantly higher in sites with AST-positive activity. The odds ratio of having high prevalence of S. intermedius, P. micros, C. concisus, B. forsythus, C. gracilis, C. rectus and S. sputigena in the presence of a positive AST site was very high (range: 3.5-17.0). Streptococcus sanguis, Actinomyces naeslundii, Gemella morbillorum, Capnocytophaga gingivalis, Veillonella parvula, Fusobacterium varium, Eubacterium lentum and Prevotella oralis were detected in significantly higher proportions in sites with AST negative activity and manifested a negative odds ratio in the presence of AST positive sites. The logistic regression analysis revealed that smoking and bleeding upon probing showed a significant association with AST activity, while plaque and suppuration were not found to be significant predictors of AST activity. The co-infection of Porphyromonas gingivalis, B. forsythus and P. micros, or P. gingivalis, B. forsythus and C. rectus were found to be significantly associated with the AST activity (p<0.001). AST positive sites revealed significantly higher occurrence of co-infections by P. gingivalis, B. forsythus, S. sputigena or by P. gingivalis, B. forsythus, S. intermedius than AST negative sites (p<0.001). P. gingivalis, B. forsythus, A. naeslundii co-infection was found significantly higher in the AST negative sites (p<0.001).

CONCLUSIONS

The present study found a high level of agreement between the presence of putative periodontal pathogens and positive AST scores at periodontal sites that clinically were considered to be potentially disease active. Prospective studies should be performed to confirm the findings.

Periodontal infections and pre-term birth: early findings from a cohort of young minority women in New York

The aim of this report is to provide early data from an ongoing study examining (i) the relationship between periodontal infections and pre-term low birth weight (PLBW) in a cohort of young, minority, pregnant and post-partum women; and (ii) the effect of periodontal interventions on pregnancy outcome. During the first 2 yr of the study, 213 women were enrolled and examined clinically for dental plaque, calculus, bleeding on probing, and probing depth. Birth outcome data were available for 164 women, including one group (n = 74) subjected to oral prophylaxis during pregnancy, and a second group (n=90) who received no prenatal periodontal treatment. Subgingival plaque samples were available from 145 subjects (4 samples/subject) and were analyzed by checkerboard DNA hybridization with respect to 12 bacterial species. The prevalence of PLBW was 16.5% (27 cases) in this cohort. No differences in clinical periodontal status were observed between PLBW cases and women with normal birth outcome. However, PLBW mothers had significantly higher levels of Bacteroides forsythus and Campylobacter rectus, and consistently elevated counts for the other species examined. PLBW occurred in 18.9% of the women who did not receive periodontal intervention (17 cases), and in 13.5% (10 cases) of those who received such therapy.

Glycosaminoglycans in gingival crevicular fluid of patients with periodontal class II furcation involvement before and after guided tissue regeneration. A pilot study

BACKGROUND

The levels of glycosaminoglycans in gingival crevicular fluid (GCF) are good indicators of underlying tissue turnover. We hypothesize that connective tissue elements in GCF may be used as indicators of tissue maturation underneath barrier membranes. Therefore, we investigated the levels of sulfated glycosaminoglycans in GCF at sites before and after guided tissue regeneration (GTR).

METHODS

Six patients were selected on the basis of having at least one Class II buccal furcation involvement on a molar tooth. Each molar furcation was treated with the standard GTR surgical protocol using a non-resorbable expanded polytetrafluoroethylene membrane. Gingival crevicular fluid samples were taken at baseline (immediately prior to insertion of the membrane) and at 1, 2, 3, 4, 5, and 6 weeks (immediately prior to removal of the membrane). Glycosaminoglycan levels were determined using an Alcian blue dye detection system.

RESULTS

The mean levels of chondroitin sulfate and total sulfated glycosaminoglycans in GCF significantly decreased during the first 4 weeks after GTR surgery. By week 5, the levels began to rise, and by week 6 the levels had returned to baseline levels.

CONCLUSIONS

Sulfated glycosaminoglycans can be monitored in GCF at healing GTR sites. It is proposed that this is a useful means of monitoring the status of the regenerating tissues. However, further longitudinal studies are required to assess if the sulfated glycosaminoglycans can be used as indicators of tissue maturation under guided tissue membranes used to treat periodontal defects.

Protective effect of serum antibodies against a 110-kilodalton protein of Actinobacillus actinomycetemcomitans following periodontal therapy

Thirty-four adult patients with untreated periodontitis were randomly assigned to receive full mouth scaling alone or scaling with an adjunctive antimicrobial therapy, both followed by supportive periodontal therapy. At 24 months, specific serum immunoglobulin A (IgA), IgG and IgG subclass antibody reactivities against a 110-kDa protein of Actinobacillus actinomycetemcomitans were assessed by Western blot. In patients harboring A. actinomycetemcomitans intraorally, the IgG4 antibody reactivity against the 110-kDa protein of A. actinomycetemcomitans was associated with significantly increased survival rates of teeth and of sites not exhibiting 2 mm or more of probing attachment loss. The same trend was found for IgG3 and IgG2 antibody reactivities, but it was statistically insignificant. No association with clinical treatment outcome was observed for IgA, IgG and IgG1 antibody reactivities. The results indicated that systemic IgG4 antibody reactivity against the 110-kDa protein of A. actinomycetemcomitans may have a protective effect against periodontal disease progression in patients harboring A. actinomycetemcomitans and receiving periodontal therapy.

Protein recovery from several paper types used to collect gingival crevicular fluid

The purpose of this study was to compare the efficiency of protein elution from several types of gingival crevicular fluid (GCF) collection papers when the volume of the inoculated protein and the elution methods were constant. Various concentrations of bovine serum albumin (BSA) and 14C-BSA were placed onto strips of Whatman #1 [W1], Whatman 3 MM chromatographic [W3], Periopaper (ProFlow) [P] and Periopaper (Harco) [H], and recovered proteins measured following a non-optimized centrifugal elution technique. There were significant differences in % recovery of BSA and 14C-BSA from the papers, which was dependent on both the type of paper and the concentration of the inoculated protein; that is, proteins at the lowest concentrations were less efficiently eluted from GCF collection papers than those at higher concentrations. Equations for regression lines of elution efficiency were quadratic. Thus, our data suggest significant differences in the efficiency for elution of BSA from absorbent papers when the volume of the inoculated fluid and the elution technique were constant. Previous variable or conflicting experimental data between research groups may have resulted from incomplete elution of proteins from GCF collection papers, possibly due to entrapment within, or binding of GCF proteins to the paper.

The relationship between concentrations of proinflammatory cytokines within gingiva and the adjacent sulcular depth

The objective of this study was to determine and compare concentrations and ratios of 3 proinflammatory cytokines, interleukin (IL) IL-1beta, IL-6, and IL-8 within gingival tissue biopsies adjacent to < or = 3, 4 to 6, or >6 mm sulci. All gingiva adjacent to > or = 4 mm sulci had clinical evidence of active inflammation. Factorial analysis of variance suggested significant effects of sulcus depth on the type and concentration of the three cytokines in the adjacent gingiva (P < 0.001). IL-8 concentrations were highest in gingiva adjacent to < or = 3 and lowest adjacent to >6 mm sulci (P < 0.001). In contrast, IL-6 concentrations were lowest in gingiva adjacent to < or = 6 mm and highest adjacent to >6 mm sites. IL-1beta concentrations were highest in gingiva adjacent to >6 mm and lowest adjacent to 4 to 6 mm sites; they were also higher adjacent to < or = 3 mm than adjacent to 4 to 6 mm sites (P < 0.01). Multiple regression analysis suggested that sulcular depth, type of cytokine, and cytokine concentration were significantly correlated (P < 0.001). Ratios of gingival cytokines changed with increased sulcular depth. In gingiva adjacent to < or = 6 mm sites, IL-8 was the most and IL-6 the least prevalent. In gingiva adjacent to > or = 6 mm sites, IL-8 was the least and IL-1-beta the most prevalent. The data suggest that the characteristics of the gingival cytokine network are affected by adjacent sulcular depth. These data could be used to design adjunct diagnostic tests for progression of periodontal diseases.

Practical periodontal screening and diagnosis

The differences in approach between screening for and diagnosis of periodontal diseases are highlighted. The Periodontal Screening and Recording procedure is discussed in terms of its evolution and current application. For patients screened and found to have more advanced periodontal problems a panoramic dental radiograph with restricted supplemented periapicals are recommended. A comprehensive clinical periodontal examination should be performed for these patients, but it is argued that this may be performed after the initial hygiene phase of treatment. In establishing a diagnosis it is suggested that attention be paid to possible risk exposures. Newer, non-anatomic diagnostic procedures are discussed in principle and it is concluded that these do not have a practical application at present.

Short chain carboxylic acids decrease human gingival keratinocyte proliferation and increase apoptosis and necrosis

Epithelia are key barriers to infections. In periodontal disease, the gingival sulcular epithelium becomes ulcerated. In this report, we test the hypothesis that short-chain carboxylic acids (SCCA) inhibit keratinocyte proliferation, increase necrosis and apoptosis, and may thus promote ulceration. SCCA produced by bacteria are present at millimolar concentrations in the periodontal pockets of subjects with periodontal disease. SCCA concentrations are higher in subjects with severe disease than in those with mild disease, and are not detectable in healthy subjects. Cell proliferation is critical for maintenance of epithelial barrier function. All SCCA tested, when neutralized, decreased epithelial cell proliferation (as measured by 3H-thymidine incorporation) in a dose-dependent manner. We found that epithelial cell viability decreased with increasing SCCA concentrations, accounting at least partly for the decreased 3H-thymidine incorporation. For all conditions we tested, SCCA-induced apoptosis preceded and exceeded necrosis. While the molecular mechanism(s) for these effects remain to be determined, the results indicate that SCCA derived from caries- or periodontal disease-associated bacteria could alter gingival barrier function.

Gingival inflammation induced by food and short-chain carboxylic acids

Earlier studies in our laboratories demonstrated that particles of a number of snack foods that are retained on the dentition accumulate fermentable sugars and short-chain carboxylic acids (SCCA; acetic, formic, lactic, and propionic) to different degrees. The present study was undertaken to test the hypothesis that the accumulated SCCA can induce a gingival inflammatory response. Five periodontally and medically healthy subjects were given portions of plain doughnuts (high SCCA levels) or oatmeal cookie (low SCCA), or had the SCCA applied directly to the gingival margins of designated teeth. Subjects were given wax to chew, or nothing, as controls. Inflammation was assessed by measurements of subgingival temperature, flow rates of gingival crevicular fluid (GCF), and neutrophil emigration into GCF. Subgingival temperatures of the maxillary gingiva rose by 1.32 +/- 0.30 degrees C (mean +/- SE) 5 min after the subjects consumed the doughnuts and remained elevated for at least 1 hr. These values were significantly higher than those obtained from subjects after ingestion of oatmeal cookies (0.63 +/- 0.17 degree C; p < 0.01), consistent with the low levels of SCCA in the retained cookie particles. Wax chewing elicited a similar response, indicating a masticatory effect on the gingiva. Gingival temperatures in the unchallenged controls remained unchanged. Neutrophil emigration into the GCF was significantly elevated in subjects after doughnut consumption. Rinses with a solution of SCCA, or application of the SCCA to the gingiva, also brought about significant elevations in subgingival temperature and neutrophil emigration. The findings describe the inflammatory effects of food ingestion on the gingiva of healthy human subjects, and support the hypothesis that SCCA in the particles of retained food are at least partly responsible for the observed responses.

The change of periapical exudate prostaglandin E2 levels during root canal treatment

We have previously demonstrated that detectable levels of prostaglandin E2 exist in periapical exudates (PE-PGE2) from root canals of periapical periodontitis. Our data from a cross-sectional study also suggested the association of PE-PGE2 concentrations with the active phase of periapical lesions. The objective of this study was to investigate the longitudinal changes of PE-PGE2 levels during root canal treatment. Periapical exudate specimens were quantitatively sampled from root canals of 20 nonvital teeth at consecutive treatment visits to measure PGE2 concentrations. The mean PE-PGE2 levels significantly decreased following the endodontic therapy (158.0 +/- 54.1 pg/microliter in the first samples versus 48.4 +/- 37.9 pg/microliter in the second samples). A significant correlation was also found between the changes in PE-PGE2 levels and the clinical disease expression of periapical periodontitis (p < 0.01). Decreased PGE2 production is considered to reflect the remission of disease activity. These results suggest the central roles of PGE2 in regulatory mechanisms for the expression of periapical disease.

Overview of clinical trials of periodontal diagnosis methods and devices

Changing views of the pathogenesis and progression of the periodontal diseases and new modalities for treatment have stimulated a plethora of physical, biochemical, microbiologic, and immunologic diagnostic procedures, tests, and devices. Clinical trials address needs for: 1) screening tests and risk assessment for disease susceptibility; 2) identification of active and progressive disease sites; 3) making therapeutic decisions; 4) monitoring therapy; 5) establishing a maintenance schedule; and 6) prognosis assessment. Needs and priorities of general, specialty, and public health practitioners differ. Validation of tests proceeds in a hierarchy of study designs from cross sectional and case control studies to retrospective and prospective longitudinal multi-center trials. For broad-scale application, randomized controlled trials (and eventual meta-analysis) will be required. Design issues are those common to all clinical trials in periodontics plus special considerations depending on type of test and its intended use. For diagnostic tests, recommended surrogate endpoints are attachment and alveolar bone levels-the traditional "gold standards." Validation of diagnostic tests is best accomplished by generation of 2 x 2 contingency tables to calculate sensitivity and specificity, positive and negative predictive values, relative and absolute risks, and odds rations. Each has a place-depending on the clinical situation and needs of the clinician.

Design principles and statistical considerations in periodontal clinical trials

Although clinical trials are a small subset of conducted biomedical research, they have become powerful investigational tools for the evaluation and approval of new treatments by clinician groups and regulatory agencies like the US Food and Drug Administration. To impact the delivery of care, trials in general must meet three criteria: clarity, comparability, and generalizability. Accordingly, trials can offer meaningful data if they have procedures which are well defined and subjects who represent a reasonably homogeneous population. The evaluation of periodontitis interventions presents several challenges due to the disease's heterogeneity and its irregular, episodic pattern; nevertheless, the intent of these novel interventions is to prevent, diagnose, inhibit, or reverse periodontal disease progression. Careful consideration of the trial's objectives should dictate clinical endpoints (primary and surrogate), comparison groups (placebo, standard therapy, test therapy), and equivalence versus superiority as the basis for conclusions. Several design elements such as control population specification, randomization, masking, sample size calculation, and standardization of procedures for patient care and assessment can decrease potential bias and variability. In both parallel and paired (split-mouth) design trials, multiplicities of endpoints, treatments, and subgroups require strategies which address the broader scope of chance findings without excessive loss of study power. Also, the longitudinal assessment of multiple periodontal sites within patients produces correlated data structures for which analytic methods need to account for the appropriate sampling unit. With these design and analytic elements, clinical trials can provide important evidence to investigators, patients, and governmental agencies for the introduction of novel interventions in periodontal practice.

Interleukin-8 and beta-glucuronidase in gingival crevicular fluid

Polymorphonuclear leukocytes (PMN) play a critical role in the host's response to the subgingival microflora. Interleukin-8 (IL-8) is a potent chemotactic and activating factor for PMN. In this study, the presence of IL-8 in gingival crevicular fluid (GCF) was examined in relation to the PMN indicator beta-glucuronidase (beta G), as well as clinical parameters of chronic inflammatory periodontal disease. Data was obtained from 30 patients with periodontitis and 14 healthy controls. For the control group, GCF and clinical data were obtained only once. For the periodontitis patients, clinical data and GCF samples were collected prior to treatment, and GCF samples were again collected 2 weeks after scaling and root planing. Comparing control and periodontitis patients prior to treatment, IL-8 concentration was lower in the patients with periodontitis. Scaling and root planing resulted in either an increase or a decrease in total IL-8 and IL-8 concentration GCF. A reduction in total IL-8 or IL-8 concentration was accompanied by a corresponding reduction in beta G activity. An increase in total IL-8 or IL-8 concentration after scaling and root planing was associated with an increase in beta G activity in some patients and a reduction in beta G activity in other patients. The periodontitis patients who did not demonstrate a linkage between IL-8 and beta G activity in GCF were those individuals with the highest beta G activity prior to treatment. As elevated beta G activity in GCF has been associated with an increased risk for probing attachment loss, the absence of a direct relationship between IL-8 in GCF and PMN recruitment into the gingival crevice may characterize individuals at risk for progression of periodontitis.

Short-chain carboxylic-acid-stimulated, PMN-mediated gingival inflammation

This communication reviews the effects of short-chain carboxylic acids on human cells of importance to the periodontium. The central hypothesis is that these acids can alter both cell function and gene expression, and thus contribute to the initiation and prolongation of gingival inflammation. Short-chain carboxylic acids [CH3-(CH2)x-COOH, x < 3] are metabolic intermediates with a broad range of apparently paradoxical biological effects. For example, lactic acid (CH3-CHOH-COOH), a 3-carbon alpha-hydroxy-substituted acid, is widely recognized for its cariogenicity. Lactic acid, however, also occurs in tropical fruits, and is the active ingredient in a variety of anti-wrinkle creams developed by dermatologists. In marked contrast, the unsubstituted 3-carbon propionic acid (CH3-CH2-COOH) is used as a food preservative and is the active principle for one class of non-steroidal anti-inflammatory agents. Interestingly, the addition of one carbon to propionic acid dramatically changes the biological effects. The unsubstituted 4-carbon butyric acid (CH3-CH2-CH2-COOH) is used by hematologists as a de-differentiating agent for the treatment of sickle cell anemia, but by oncologists as a differentiating agent for cancer chemotherapy. Finally, acting either individually or in concert, these acids can increase vascular dilation. Clearly, these acids, while metabolically derived, have a number of very divergent activities which are cell-type-specific (Fig. 1). It may be telling that periodontal bacteria produce these acids in millimolar concentrations, and that these bacteria can be characterized by their acid production profiles. It is no less interesting that these acids occur in the gingival crevices of human subjects with severe periodontal disease at millimolar levels which are > 10-fold higher than those found in mildly diseased subjects, and are undetectable in healthy subjects. Further, when applied directly to healthy human gingiva, short-chain carboxylic acids stimulate a gingival inflammatory response and inflammatory cytokine release. At the cellular level, these acids inhibit proliferation of gingival epithelial and endothelial cells, and inhibit leukocyte apoptosis and function, but can stimulate leukocyte cytokine release. At the molecular level, these acids can stimulate neutrophil gene transcription, translation, and protein expression. Thus, the likelihood is high that these acids, in addition to their cariogenic activity, can promote and prolong gingival inflammation. Our challenge will be to identify the cell or cells of the periodontium which respond to short-chain carboxylic acids, to delineate their responses and the molecular mechanism(s) of these effects, and to categorize the aspects of the inflammatory components which damage and those which protect the host. With this information, it may be possible to begin to rationally identify and test pharmaceutical agents which diminish the harmful aspects, while enhancing the beneficial components, of the inflammatory response.

Periodontal disease and cardiovascular disease

It is our central hypothesis that periodontal diseases, which are chronic Gram-negative infections, represent a previously unrecognized risk factor for atherosclerosis and thromboembolic events. Previous studies have demonstrated an association between periodontal disease severity and risk of coronary heart disease and stroke. We hypothesize that this association may be due to an underlying inflammatory response trait, which places an individual at high risk for developing both periodontal disease and atherosclerosis. We further suggest that periodontal disease, once established, provides a biological burden of endotoxin (lipopolysaccharide) and inflammatory cytokines (especially TxA2, IL-1 beta, PGE2, and TNF-alpha) which serve to initiate and exacerbate atherogenesis and thromboembolic events. A cohort study was conducted using combined data from the Normative Aging Study and the Dental Longitudinal Study sponsored by the United States Department of Veterans Affairs. Mean bone loss scores and worst probing pocket depth scores per tooth were measured on 1,147 men during 1968 to 1971. Information gathered during follow-up examinations showed that 207 men developed coronary heart disease (CHD), 59 died of CHD, and 40 had strokes. Incidence odds ratios adjusted for established cardiovascular risk factors were 1.5, 1.9, and 2.8 for bone loss and total CHD, fatal CHD, and stroke, respectively. Levels of bone loss and cumulative incidence of total CHD and fatal CHD indicated a biologic gradient between severity of exposure and occurrence of disease.

The effect of tetracycline fiber therapy on beta-glucuronidase and interleukin-1 beta in crevicular fluid

Treatment with the tetracycline HCL-containing (Actisite infinity) fiber has been shown to improve clinical measures of periodontitis, as well as reduce the number of sites infected with putative periodontal pathogens. In this study, we examined the effect of the tetracycline fiber on biochemical mediators of the host's inflammatory response in gingival crevicular fluid (GCF). The total amount of the lysosomal enzyme beta-glucuronidase (beta G), considered a marker of primary granule release from polymorphonuclear leukocytes and interleukin-1 beta, a cytokine with important proinflammatory effects, were examined in GCF. Patients with localized recurrent periodontitis were followed over a 16 week period. Treated teeth (Tx), teeth adjacent to treated teeth (ADJ) and control teeth (Cx) were studied. Following fiber therapy, the Tx teeth displayed statistically significant reductions in mean probing depth, depth of the deepest site and bleeding on probing over the 16 weeks of the trial. Significant reduction in the depth of the deepest site was also seen for the ADJ teeth over 16 weeks. Total beta G in GCF was reduced for the Tx teeth comparing baseline to 16 weeks, but no significant changes were observed for the ADJ or Cx teeth. Prior to treatment, total beta G for the Tx teeth was 211 +/- 49 U (mean +/- standard error), versus 146 +/- 174 U for the ADJ teeth and 121 +/- 33 U for the Cx teeth. 16 weeks treatment, the mean values for these 3 categories of teeth were comparable (Tx = 95 +/- 20 U, ADJ = 93 +/- 42 U and Cx = 103 +/- 29 U). For the Tx teeth, the maximum reduction in total beta G following therapy occurred at 6 weeks (65%). Total IL-1 beta was significantly reduced for the Tx teeth at 3 and 6 weeks, but rebounded at 16 weeks. In contrast to what was seen for beta G, the maximum reduction in total IL-1 beta for the Tx teeth was observed at 3 weeks (68%). These data suggest that host mediators associated with increased risk for active disease are reduced following tetracycline fiber therapy. Future studies will determine the relative importance of a reduced microbial challenge versus a tetracycline-mediated direct modification of the host response to account for the reduction in the host inflammatory response in GCF following tetracycline fiber therapy.

Serendipity or luck: stumbling on gingival crevicular fluid

The word "serendipity" comes from the tale "The Three Princes from Serendip" by Horace Walpole. It is defined as an aptitude for making fortunate discoveries accidentally." The demonstration of crevicular fluid was truly an accidental discovery. Niels Brill, a successful private practitioner in Copenhagen with prosthodontics as a specialty, and Bo Krasse, associate professor of cariology, were examining the microflora of gingival pockets in a dog. Before the samples were taken, gingiva and teeth were disinfected with an iodine solution. The solution disappeared from different pockets at different speeds. After intravenous injection of a fluorescein solution, the occurrence of fluorescein could be recorded on filter paper strips. Thus, after stumbling on the disappearance of iodine from the cervical areas of the teeth, two non-periodontologists managed to demonstrate why it disappeared. This article describes the details of the discovery and subsequent studies, and offers some reflections by one of the original authors 37 years later.

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.

Turnover in periodontal connective tissues: dynamic homeostasis of cells, collagen and ground substances

The connective tissues of the periodontium are composed of two soft tissues and two hard tissues--each of which has unique features. This review considers the constituents of normal, healthy periodontal connective tissues together with an appraisal of the changes in the connective tissue matrices of the periodontium which occur during the development of periodontitis. Recent developments in this field have paved the way for new and exciting vistas in periodontal diagnosis and regeneration which, ultimately, are two important goals in periodontal therapy.