Early-onset periodontitis: systemic aspects of etiology and pathogenesis

Risk indicators of aggressive periodontitis in a Jordanian population

BACKGROUND

Knowledge of the risk indicators of aggressive periodontitis (AgP) will help clinicians to better diagnose the disease, put a treatment plan that involves modification of modifiable risk indicators, understand non-modifiable risk indicators, and may potentially serve as an aid in developing preventive programs. The objective of the present study was to assess risk indicators of aggressive periodontitis (AgP) in Jordan including socio-demographic factors, oral hygiene habits, smoking, family history and parents' consanguinity.

METHODS

A total of 162 patients (81 AgP and 81 controls), attending the Periodontology clinic at Jordan University of Science and Technology, Dental Teaching Centre, were interviewed and examined. All AgP subjects had full periodontal and radiographic examination. The data recorded included socio-demographic and economic variables, oral hygiene and smoking habits, family history and parents' consanguinity.

RESULTS

Most AgP patients were young females, had ≤12 years of education, lived in urban areas and brushed their teeth ≥ once daily. Risk indicators of AgP included: age > 35 years, female gender and positive family history.

CONCLUSIONS

Risk indicators associated with AgP in this study population were: age > 35 years, female gender and positive family history of periodontal disease.

Periodontal disease susceptible matrilines in the Cayo Santiago Macaca mulatta macaques

OBJECTIVE AND BACKGROUND

The expression of periodontitis, including age of onset, extent, and severity is considered to represent an interaction of the individual's oral microbiome and host response to the microbial challenge that is modified by both genetics and environmental factors. The aim of this study was to determine the distribution of periodontitis in a population of nonhuman primates, to document features of familial distribution that could reflect heritability and transmission of microbes with enhanced virulence.

MATERIAL AND METHODS

This report presents our findings from evaluation of periodontal disease bone defects in skulls from 569 animals (5-31 years of age) derived from the skeletons of the rhesus monkeys (Macaca mulatta) of Cayo Santiago derived from eight matrilines over 6-9 generations. The distance from the base of alveolar bone to the cemento-enamel junction on 1^st /2^nd premolars and 1^st /2^nd molars from all four quadrants was evaluated as a measure of periodontal disease. Additionally, we documented the presence of periodontitis in 79 living descendants within these matrilines.

RESULTS

The results demonstrated an increased extent and severity of periodontitis with aging across all matrilines. Extensive heterogeneity in disease expression was observed among the animals and this was linked to specific periodontitis susceptible matrilines. Moreover, we identified some matrilines in which the members appeared to show some resistance to more severe disease, even with aging.

CONCLUSION

Linking these disease variations to multigenerational matriarchal family units supported familial susceptibility of periodontitis. This familial disease relationship was reinforced by the distribution of naturally-occurring periodontitis in the living descendants.

Antibiotic effects against periodontal bacteria in organ cultured tissue

Mechanical reduction of infectious bacteria by using physical instruments is considered the principal therapeutic strategy for periodontal disease; addition of antibiotics is adjunctive. However, local antibiotic treatment, combined with conventional mechanical debridement, has recently been shown to be more effective in periodontitis subjects with type 2 diabetes. This suggests that some bacteria may invade the inflamed inner gingival epithelium, and mechanical debridement alone will be unable to reduce these bacteria completely. Therefore, we tried to establish infected organ culture models that mimic the inner gingival epithelium and aimed to see the effects of antibiotics in these established models. Mouse dorsal skin epithelia were isolated, and periodontal bacteria were injected into the epithelia. Infected epithelia were incubated with test antibiotics, and colony-forming ability was evaluated. Results indicated that effective antibiotics differed according to injected bacteria and the bacterial combinations tested. Overall, in organ culture model, the combination of amoxicillin or cefdinir and metronidazole compensate for the effects of less effective bacterial combinations on each other. This in vitro study would suggest effective periodontal treatment regimens, especially for severe periodontitis.

Inflammatory Response Influences Treatment of Localized Aggressive Periodontitis

We previously reported a systemic hyperinflammatory response to bacterial lipopolysaccharide (LPS) in children with localized aggressive periodontitis (LAP). Additionally, different levels of this response were observed within the LAP group. It is unknown whether this hyperinflammatory response influences the clinical response to periodontal treatment in these children. Therefore, the goal of this study was to evaluate the influence of LPS responsiveness present prior to treatment on the clinical response to treatment within the LAP cohort. Prior to treatment, peripheral blood was collected from 60 African American participants aged 5 to 21 y, free of systemic diseases, and diagnosed with LAP. Blood was stimulated with ultrapure LPS from Escherichia coli, and Luminex assays were performed to quantify 14 cytokine/chemokine levels. Principal component and cluster analyses were used to find patterns of cytokine/chemokine expression among participants and subdivide them into clusters. Three distinct clusters emerged among LAP participants: a high responder group (high level of response for INFg, IL6, and IL12p40), a mixed responder group (low for some and high for other cytokines/chemokines), and a low responder group (low overall cytokine/chemokine response). Periodontal clinical parameters were compared among these groups prior to and 3, 6, and 12 mo following treatment with mechanical debridement and systemic antibiotics. High responders presented the lowest reductions in clinical parameters after treatment, whereas the low responders presented the highest reductions. In our LAP participants, distinct patterns of LPS response were significantly predictive of changes in clinical parameters after treatment. Future studies are needed to evaluate the underlying mechanisms predicting the heterogeneity of LAP activity, severity, and response to treatment (ClinicalTrials.gov NCT01330719).

Familial periodontal disease in the Cayo Santiago rhesus macaques

Substantial ongoing research continues to explore the contribution of genetics and environment to the onset, extent and severity of periodontal disease(s). Existing evidence supports that periodontal disease appears to have an increased prevalence in family units with a member having aggressive periodontitis. We have been using the nonhuman primate as a model of periodontal disease for over 25 years with these species demonstrating naturally occurring periodontal disease that increases with age. This report details our findings from evaluation of periodontal disease in skulls from 97 animals (5-31 years of age) derived from the skeletons of the rhesus monkeys (Macaca mulatta) on Cayo Santiago. Periodontal disease was evaluated by determining the distance from the base of the alveolar bone defect to the cemento-enamel junction on 1st/2nd premolars and 1st/2nd molars from all four quadrants. The results demonstrated an increasing extent and severity of periodontitis with aging across the population of animals beyond only compensatory eruption. Importantly, irrespective of age, extensive heterogeneity in disease expression was observed among the animals. Linking these variations to multi-generational matriarchal family units supported familial susceptibility of periodontitis. As the current generations of animals that are descendants from these matrilines are alive, studies can be conducted to explore an array of underlying factors that could account for susceptibility or resistance to periodontal disease.

Adjunctive use of antibiotics in periodontal therapy

Periodontal diseases are infectious diseases with a mixed microbial aetiology and marked inflammatory response leading to destruction of underlying tissue. Periodontal therapy aims to eliminate pathogens associated with the disease and attain periodontal health. Periodontitis is generally treated by nonsurgical mechanical debridement and regular periodontal maintenance care. Periodontal surgery may be indicated for some patients to improve access to the root surface; however, mechanical debridement alone may not be helpful in all cases. In such cases, adjunctive systemic antibiotic therapy remains the treatment of choice. It can reach microorganisms at the base of the deep periodontal pockets and furcation areas via serum, and also affects organisms residing within gingival epithelium and connective tissue. This review aims to provide an update on clinical issues regarding when and how to prescribe systemic antibiotics in periodontal therapy. The points discussed are the mode of antibiotic action, susceptible periodontal pathogens, antibiotic dosage, antibiotic use in treatment of periodontal disease, and mechanism of bacterial resistance to each antibiotic.

Oral biology in middle age: a history of the University at Buffalo Oral Biology PhD Program

In 1960, the first Department of Oral Biology in the United States dedicated to the conduct of research, graduate biomedical research education, and the provision of basic oral science education for the DDS curriculum was established at the University at Buffalo. In 1963, the Department organized the first PhD Program in Oral Biology in the United States. This PhD program has produced a large cadre of oral health researchers, many of whom have gone on to make major contributions to dental research and education. This article provides a brief history of the program, the context within which the program was organized and developed, and a description of some of the many faculty, students, and fellows associated with the program. Additionally, to celebrate the 50th anniversary of this program, a symposium, entitled "The Oral Microbiome, Immunity and Chronic Disease", was held on June 12-14, 2013, in Buffalo, New York. The proceedings are published online in Advances in Dental Research (2014, Vol. 26).

T helper cells from aggressive periodontitis patients produce higher levels of interleukin-1 beta and interleukin-6 in interaction with Porphyromonas gingivalis

OBJECTIVE

In this study, we analyzed the production of Interleukin-1 beta (IL-1β) and IL-6 by activated CD4+ cells obtained from aggressive periodontitis (AgP) patients in comparison with healthy subjects (HC).

MATERIALS AND METHODS

CD4+ cells were automatically separated from lymphocytes obtained from peripheral blood of patients with AgP and healthy controls. Cells were activated for 4, 8, and 24 h with three different stimuli: anti-CD3/anti-CD28, phytohemagglutinin (PHA), and Porphyromonas gingivalis (P. gingivalis) outer membrane protein (OMP). Protein levels were measured in supernatants of activated CD4+ cells by a bead-based immunoassay (CBA). In addition, serum antibodies against P. gingivalis were determined. Data were analyzed using U test (p < 0.05).

RESULTS

T helper cells of AgP patients activated with P. gingivalis OMP produced higher levels of IL-1β and IL-6 in comparison with healthy controls (p < 0.05). Neither the activation with anti-CD3/anti-CD28 nor the activation with PHA showed significantly different production of IL-1β and IL-6 by the cells 25 % of patients and 17 % of controls presented with high serum reactivity to P. gingivalis.

CONCLUSION

In view of these results, it is possible to conclude that P. gingivalis contributes to the pathogenesis of AgP by inducing high levels of pro-inflammatory cytokines such as IL-1β and IL-6 by peripheral CD4+ T helper cells.

CLINICAL RELEVANCE

In accordance with the clinical parameters and the immunological data, we suggest that full-mouth disinfection with adjunctive systemic antibiotics might be the anti-infectious non-surgical periodontal treatment of choice in this type of patients. Microbiological analyses at the beginning and at the end of the periodontal treatment are recommended. However, it is necessary to verify these data in longitudinal clinical studies.

Periodontal disease immunology: 'double indemnity' in protecting the host

During the last two to three decades our understanding of the immunobiology of periodontal disease has increased exponentially, both with respect to the microbial agents triggering the disease process and the molecular mechanisms of the host engagement maintaining homeostasis or leading to collateral tissue damage. These foundational scientific findings have laid the groundwork for translating cell phenotype, receptor engagement, intracellular signaling pathways and effector functions into a 'picture' of the periodontium as the host responds to the 'danger signals' of the microbial ecology to maintain homeostasis or succumb to a disease process. These findings implicate the chronicity of the local response in attempting to manage the microbial challenge, creating a 'Double Indemnity' in some patients that does not 'insure' health for the periodontium. As importantly, in reflecting the title of this volume of Periodontology 2000, this review attempts to inform the community of how the science of periodontal immunology gestated, how continual probing of the biology of the disease has led to an evolution in our knowledge base and how more recent studies in the postgenomic era are revolutionizing our understanding of disease initiation, progression and resolution. Thus, there has been substantial progress in our understanding of the molecular mechanisms of host-bacteria interactions that result in the clinical presentation and outcomes of destructive periodontitis. The science has embarked from observations of variations in responses related to disease expression with a focus for utilization of the responses in diagnosis and therapeutic outcomes, to current investigations using cutting-edge fundamental biological processes to attempt to model the initiation and progression of soft- and hard-tissue destruction of the periodontium. As importantly, the next era in the immunobiology of periodontal disease will need to engage more sophisticated experimental designs for clinical studies to enable robust translation of basic biologic processes that are in action early in the transition from health to disease, those which stimulate microenvironmental changes that select for a more pathogenic microbial ecology and those that represent a rebalancing of the complex host responses and a resolution of inflammatory tissue destruction.

IL-17 in sera from patients with aggressive periodontitis

Interleukin-17 (IL-17), the prototype cytokine produced by the Th17 subset of T-helper cells, plays a role in inflammatory responses, autoimmunity, and antimicrobial responses in a variety of infectious and inflammatory diseases. In view of the inflammatory nature and severity of aggressive periodontitis, we hypothesized that IL-17 might be detected in sera from patients with aggressive periodontitis. We used ELISA to measure IL-17 serum concentrations from 67 periodontally healthy (NP) individuals and from 53 patients with localized (LAgP) and 49 patients with generalized (GAgP) aggressive periodontitis. IL-17 was barely detectable in sera from periodontally healthy individuals (1.9 +/- 2.0 pg/mL), but was present at significantly higher concentrations in sera from those with LAgP (7.6 +/- 2.2 pg/mL) and GAgP (17.1 +/- 2.3 pg/mL). Multivariate analyses demonstrated associations of IL-17 concentrations with periodontal attachment loss, but not with current smoking. Therefore, Th17 responses may be characteristic of AgP, and IL-17 may play a role in the pathogenesis of aggressive periodontitis.

Analysis of the association of polymorphism in the osteoprotegerin gene with susceptibility to chronic kidney disease and periodontitis

BACKGROUND AND OBJECTIVE

Chronic kidney disease (CKD) is a complex disorder, which results in several complications involving disturbance of mineral metabolism. Periodontal disease is an infectious disease that appears to be an important cause of systemic inflammation in CKD patients. Periodontal disease is characterized by clinical attachment loss (CAL) caused by alveolar bone resorption around teeth, which may lead to tooth loss. Osteoprotegerin (OPG) is a key regulator of osteoclastogenesis. Polymorphisms are the main source of genetic variation, and single nucleotide polymorphisms (SNPs) have been reported as major modulators of disease susceptibility. The aim of this study was to investigate the association of a polymorphism located at position -223 in the untranslated region of the OPG gene, previously known as -950, with susceptibility to CKD and periodontal disease.

MATERIAL AND METHODS

A sample of 224 subjects without and with CKD (in hemodialysis) was divided into groups with and without periodontal disease. The OPG polymorphism was analyzed by polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

No association was found between the studied OPG polymorphism and susceptibility to CKD or periodontal disease.

CONCLUSION

It was concluded that polymorphism OPG-223 (C/T) was not associated with CKD and periodontal disease in a Brazilian population. Studies on other polymorphisms in this and other genes of the host response could help to clarify the involvement of bone metabolism mediators in the susceptibility to CKD and periodontal disease.

Anti-cardiolipin and increased serum adhesion molecule levels in patients with aggressive periodontitis

BACKGROUND

We observed that a significant proportion of patients with periodontitis have elevated serum levels of beta2-glycoprotein-I-dependent anti-cardiolipin (anti-CL). These prothrombotic autoantibodies, commonly found to be elevated in patients with systemic lupus erythematosus and the antiphospholipid syndrome, are associated with adverse pregnancy outcomes, such as fetal involution, prematurity, and low birth weight, and with cardiovascular sequelae, such as atherosclerosis, stroke, and myocardial infarction. Anti-CL is known to promote vascular inflammation and thrombosis.

METHODS

We measured serum levels of markers of vascular inflammation, including soluble intercellular adhesion molecule (sICAM)-1, soluble vascular cell adhesion molecule (sVCAM)-1, and sE-selectin, in 190 subjects with generalized aggressive or chronic periodontitis and in 90 periodontally healthy subjects.

RESULTS

sVCAM-1 and sE-selectin levels were significantly higher in patients with elevated anti-CL (>15 U/ml). This relationship also was observed in the never-smoker subset of subjects, even after correction for demographic and periodontal variables. Within the diagnostic categories, sICAM-1, sVCAM-1, and sE-selectin were significantly higher in generalized aggressive periodontitis patients who had elevated anti-CL compared to those with normal anti-CL. Statistical correction for demographic and periodontal variables indicated that elevated anti-CL remained significantly associated with increased sVCAM-1 and sE-selectin in generalized aggressive periodontitis patients.

CONCLUSIONS

Systemic markers of vascular inflammation in patients with aggressive periodontitis are associated with elevated levels of anti-CL. We hypothesize that a subset of periodontitis patients with elevated antiphospholipid antibodies could represent a subgroup at increased risk for obstetrical and cardiovascular sequelae.

NADPH oxidase (CYBA) and FcgammaR polymorphisms as risk factors for aggressive periodontitis: a case-control association study

INTRODUCTION

Neutrophils (PMN) in aggressive periodontitis (AgP) patients have been reported to be hyperactive especially with regards to superoxide production. Polymorphisms in genes influencing PMN function have been proposed as candidate risk factors for AgP. The aim of this study was to test the association of specific gene polymorphisms affecting PMN functions with AgP.

MATERIALS AND METHODS

Two hundred and twenty-four patients with confirmed diagnosis of AgP and 231 subjects with healthy periodontium took part in the study. A blood sample was collected from subjects and genotypes for p22phox (CYBA) NADPH oxidase, FP, Fcalpha and Fcgamma receptors were analysed in a blind fashion.

RESULTS

The C242T p22phox NADPH oxidase T allele was significantly associated with AgP in a multiple logistic regression model adjusting for confounders, and this was observed for all subjects [p = 0.002, odds ratio (OR) = 1.87, 95% confidence interval (CI) = 1.27-2.83] and Caucasians (p = 0.009, OR=2.07, 95% CI = 1.20-3.59). Concomitant presence of C242T p22phox NADPH oxidase T allele and FcgammaRIIIb NA1 homozygosity was associated with the generalized AgP phenotype in Caucasians (p = 0.001, OR = 30.35, 95% CI = 3.81-241.97).

CONCLUSIONS

C242T p22phox NADPH oxidase and FcgammaR polymorphisms may predispose to AgP through a modulation of neutrophil superoxide production.

Association of matrix metalloproteinase-1 promoter polymorphism with generalized aggressive periodontitis in a Chinese population

BACKGROUND

A single nucleotide polymorphism in the promoter region of -1607 bp of the human matrix metalloproteinase-1 (MMP-1) gene has been found to be associated with an increased risk of various inflammatory diseases and cancer metastasis.

OBJECTIVES

The present study aimed to examine the distribution of MMP-1 genotypes in a group of Chinese subjects with generalized aggressive periodontitis and a group of periodontally healthy subjects, and to evaluate the possible association of the MMP-1 promoter polymorphism with aggressive periodontitis.

METHODS

Genomic DNA was obtained from whole blood samples in 40 Chinese subjects with generalized aggressive periodontitis and 52 periodontally healthy subjects as controls. MMP-1 promoter fragment was amplified by polymerase chain reaction, and the polymorphisms were analyzed by restriction endonuclease cleavage. The alleles were detected by polyacrylamide gel electrophoresis and visualized with ethidium bromide.

RESULTS

The detection frequency of 2G allele was significantly higher in the subjects with generalized aggressive periodontitis (68.7%) than in the control subjects (49%) (p < 0.01). The genotype of 2G/2G was found in 52.5% of the patients, which was significantly greater than that of control subjects (23.1%) (p < 0.05).

CONCLUSION

The present study suggests that a single nucleotide polymorphism in the MMP-1 promoter region of -1607 bp may be associated with generalized aggressive periodontitis in Chinese population.

Systemic antibiotics in periodontics

This position paper addresses the role of systemic antibiotics in the treatment of periodontal disease. Topical antibiotic therapy is not discussed here. The paper was prepared by the Research, Science and Therapy Committee of the American Academy of Periodontology. The document consists of three sections: 1) concept of antibiotic periodontal therapy; 2) efficacy of antibiotic periodontal therapy; and 3) practical aspects of antibiotic periodontal therapy. The conclusions drawn in this paper represent the position of the American Academy of Periodontology and are intended for the information of the dental profession.

Quantitative Measures of Aggressive Periodontitis Show Substantial Heritability and Consistency With Traditional Diagnoses

BACKGROUND

Aggressive periodontitis (AgP) research nearly always classifies subjects into traditional discrete categories of localized or generalized, based upon degree of attachment loss (AL) and types of affected teeth. Since AL is continuous and quantitative, however, useful information is lost. We developed quantitative measures of AgP, compared these to traditional methods, and estimated heritabilities in families.

METHODS

We examined 237 healthy, 169 localized AgP, and 204 generalized AgP subjects. We used the site of maximum AL of each tooth to calculate means for each subject for different groups of teeth. We also applied principal components analysis (PCA) to condense variation among 28 teeth into three orthogonal (uncorrelated) variables. We used discriminant function analysis (DFA) to evaluate how well the quantitative measures match with traditional classifications. Quantitative trait heritabilities were estimated by variance components.

RESULTS

PCA clustered first molars, incisors, and the other teeth into three groups. DFA showed that quantitative measures classified subjects consistent with traditional methods (87% to 94% agreement). Heritabilities ranged from 13.7% (P = 0.10) to 30.0% (P = 0.008) for quantitative measures, with highest values obtained for first molars. A combination of the principal component variables most heavily weighted on first molars and incisors gave the best model of disease susceptibility, with good separation of healthy versus diseased subjects, independent of disease extent or severity.

CONCLUSIONS

Quantitative measures may provide improved precision and power for many kinds of periodontal research. Our finding of significant heritability supports their use in gene mapping studies of AgP susceptibility.

Polymorphisms in the vitamin D receptor gene are associated with periodontal disease

BACKGROUND

Genetic polymorphisms in the vitamin D receptor (VDR) gene are associated with bone homeostasis and diseases in which bone loss is a cardinal sign. The aim of this study was to determine whether chronic periodontal disease in a Brazilian population is associated with polymorphisms in the VDR gene.

METHODS

Clinical examination and recordings of probing depth and clinical attachment level were performed in 113 unrelated adults who were divided into two groups: 44 healthy individuals (control group) and 69 subjects with chronic periodontitis (CP). DNA was obtained from the subjects' epithelial cells by scraping the buccal mucosa. Two polymorphisms in the VDR gene were analyzed by polymerase chain reaction, followed by Taql and BsmI restriction endonuclease digestion.

RESULTS

Frequencies of VDR/TaqI and VDR/BsmI showed significant differences between the control group and the CP group (P < 0.05). The "Tb" haplotype was prevalent in the control group (43.2%), and the "TB" haplotype in the CP group (36.6%). The "TB" haplotype seemed to increase susceptibility to periodontal disease (odds ratio [OR] = 2.19). The heterozygous haplotype "TB/tb" was predominant in the CP group (OR = 4.32; P = 0.005).

CONCLUSIONS

TaqI and BsmI polymorphisms of the VDR gene are associated with clinical attachment loss due to periodontal disease in a Brazilian population. These findings suggest that VDR genotype might be a risk indicator for susceptibility to chronic periodontitis.

Microbiological profile of early onset/aggressive periodontitis patients

OBJECTIVES

The objectives of this study were to characterize the bacterial profile and to seek possible bacterial associations in the subgingival microbiota of early onset periodontitis/aggressive periodontitis patients by using two different techniques, culture and immunofluorescence.

MATERIAL AND METHODS

The study group consisted of 66 systemically healthy individuals with evidence of early onset periodontitis - 41 females and 25 males aged 23-35 years (mean 31.1 +/- 3.1 years). Bacterial samples were collected from the deepest site in each quadrant, resulting in a total of 264 sites with a mean probing pocket depth of 6.6 +/- 1.5 mm. Samples were cultured anaerobically and in 10% CO(2) using selective and nonselective media, and isolates were characterized to species level. Indirect immunofluorescence using monoclonal antibodies was applied to detect Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia (Bacteroides forsythus, Tannerella forsythensis), Prevotella intermedia/Prevotella nigrescens, Campylobacter rectus, Peptostreptococcus micros and Actinomyces israelii.

RESULTS

93.6% of sampled sites showed bleeding on probing and 23.5% were positive for suppuration. P. intermedia/P. nigrescens, P. gingivalis, and C. rectus were detected in 77.3-85.9% of samples using culture methods and in 85.6-91.3% using immunofluorescence. P. micros and A. actinomycetemcomitans were found, respectively, in 63.3% and 25.0% of all sites using culturing and in 58.7% and 27.7% sites using immunofluorescence. Significantly strong positive associations were observed between T. forsythia and C. rectus (odds ratio 109.46), and T. forsythia and P. gingivalis (odd ratio 90.26), whereas a negative association was seen between P. intermedia/P. nigrescens and A. actinomycetemcomitans (odds ratio 0.42). Coinfection by P. gingivalis, T. forsythia, P. intermedia/P. nigrescens and C. rectus was observed in 62.1% of the test sites, and in 89.4% of the studied subjects. The sensitivity of immunofluorescence for T. forsythia, C. rectus, P. intermedia/P. nigrescens and P. gingivalis was found to be very high (0.99-0.94) using culture as the reference detection method. The agreement between culture and immunofluorescence in detecting the presence or absence of the investigated species was 85.2-88.1% for P. gingivalis, P. intermedia/P. nigrescens, C. rectus, and T. forsythia, 75.9% for A. actinomycetemcomitans and 70.4% for P. micros.

CONCLUSIONS

The microbial profile of the early onset/aggressive periodontitis population was complex. The agreement between the two detection methods was very high.

Dendritic cells stimulated with Actinobacillus actinomycetemcomitans elicit rapid gamma interferon responses by natural killer cells

Human immunoglobulin G2 (IgG2) responses are gamma interferon (IFN-gamma) dependent, and monocyte-derived dendritic cells (mDCs) promote IgG2 production. DCs spontaneously emerge from monocytes in cultures prepared from localized aggressive periodontitis (LagP) patients, and these patients have high levels of IgG2 that is reactive with Actinobacillus actinomycetemcomitans. These results prompted the hypothesis that an interaction between mDCs and A. actinomycetemcomitans promotes IFN-gamma production, and IFN-gamma is known to promote both immunopathology and protective IgG2. A. actinomycetemcomitans induced mDCs to produce interleukin-12 (IL-12), and the addition of A. actinomycetemcomitans and DCs to cultured peripheral blood lymphocytes elicited high levels of IFN-gamma within just 24 h. In contrast, IL-4 was not detectable although DC-derived IL-10 production was apparent. A. actinomycetemcomitans-stimulated macrophages prepared from the same monocytes lacked the ability to induce IL-12 or IFN-gamma responses. NK cells of the innate immune system were the primary source of this early IFN-gamma, although CD8 T cells also contributed some. The NK cell-derived IFN-gamma was IL-12 dependent, and A. actinomycetemcomitans-DC interactions were Toll-like receptor 4 dependent. A. actinomycetemcomitans and A. actinomycetemcomitans lipopolysaccharide (LPS) were more potent than Escherichia coli and E. coli LPS in the ability to induce DC IL-12 and IFN-gamma. The ability of A. actinomycetemcomitans-stimulated DCs to induce NK cells to rapidly produce IFN-gamma in the absence of detectable IL-4 suggests their potential for skewing responses toward Th1. This may help explain the presence of Th1-associated cytokines in gingival crevicular fluid (GCF) from LagP patients and the high levels of IgG2 in their serum and GCF that is reactive with A. actinomycetemcomitans.

Evaluation of additional amine fluoride/stannous fluoride-containing mouthrinse during supportive therapy in patients with generalized aggressive periodontitis. A randomized, crossover, double-blind, controlled trial

OBJECTIVES

The objective of the present randomized controlled trial was to evaluate the efficacy of a mouthrinse containing a combination of AmF/SnF2 in controlling supragingival plaque accumulation and gingival inflammation during a 12-week period in patients affected by generalized aggressive periodontitis (GAP).

METHODS

Eighteen subjects, six males and 12 females, mean age: 32.2 years, were evaluated. One-half of the patients was either prescribed an AmF/SnF2-containing mouthrinse (test mouthrinse) or a control mouthrinse in addition to mechanical plaque control for 12 weeks. After a 2-week wash-out period, the patients received the alternative mouthrinse. Before and after treatment plaque index (PlI), gingival index (GI), angulated bleeding index (AngBI), tooth stain (GMSI), and tongue stain were recorded.

RESULTS

Test mouthrinse resulted in a statistically significant decrease in PlI (p = 0.029) and GI (p = 0.017). After treatment, PlI was significantly lower in test compared to control mouthrinse (p = 0.027). GMSI significantly increased post-treatment for both mouthrinse regimens (p < 0.001), a significantly higher score being observed for the test compared to control mouthrinse (p = 0.002).

CONCLUSIONS

The 12-week use of a AmF/SnF2-containing mouthrinse as an adjunct to conventional mechanical oral hygiene procedures in GAP patients was effective in controlling the amount of supragingival plaque deposits.

Hereditary gingival fibromatosis associated with generalized aggressive periodontitis: a case report

BACKGROUND

Hereditary gingival fibromatosis is a rare, genetically inherited overgrowth condition that is clinically characterized by a benign fibrous enlargement of maxillary and mandibular keratinized gingiva. A syndromic association between gingival fibromatosis and a wide variety of other genetically inherited disorders has been described. However, its coexistence with aggressive periodontitis has not been reported.

METHODS

A 24-year-old African-American female, patient (proband X, [Px]) reported with a chief complaint of tooth mobility and gingival enlargement. Clinical examination revealed moderate to severe gingival overgrowth on both mandible and maxilla. Generalized attachment loss and mobility of the teeth were observed. Radiographic evaluation demonstrated severe alveolar bone loss. The patient was diagnosed with gingival fibromatosis and aggressive periodontitis based on the clinical and radiographic findings. Her brother (Bx) and her mother (Mx) were evaluated and diagnosed with gingival fibromatosis suggesting that this is a dominant trait in the family and gingival fibromatosis might be of hereditary origin. In addition, the brother also exhibited localized aggressive periodontitis. Medical history revealed no other systemic or local contributory factors associated with the oral findings in any of the subjects.

RESULTS

Surgical therapy included internal bevel gingivectomy combined with open flap debridement procedures for Px and Bx. Only internal bevel gingivectomy was performed for Mx since there was mild bone resorption and no intrabony defects. At the time of surgery, gingival biopsies were obtained and fixed in 4% paraformaldehyde. Multiple serial sections were stained with hematoxylin and eosin. Microscopic evaluation of the gingival specimens revealed large parallel collagen bundles associated with scarce fibroblasts in the connective tissue. The collagen bundles reached into the subepithelial connective tissue where elongated rete-pegs were also observed. Following the completion of the treatment, no signs of recurrence or bone resorption were observed over 2-year follow-up.

CONCLUSIONS

This is the first report of hereditary gingival fibromatosis associated with aggressive periodontitis. Combined treatment comprising removal of fibrotic gingival tissue and traditional flap surgery for the elimination of intrabony defects represents a unique treatment approach in periodontal therapy. Two-year follow-up revealed that both the gingival overgrowth and the destructive lesions were successfully treated.

The influence of tobacco smoking on the onset of periodontitis in young persons

This paper reviews the evidence for cigarette smoking as a risk factor for the development of severe destructive periodontal disease in young adults. A high prevalence of cigarette smoking has been identified among young individuals with aggressive periodontitis and tobacco usage increases the risk of periodontal destruction most significantly in young populations. The effect appears to be dose related and is independent of levels of plaque accumulation. Young smokers have more alveolar bone loss and attachment loss than non smoking equivalents. Prolonged and heavy smoking can reduce gingival bleeding and therefore mask the clinical marker of bleeding on probing often used by dentists to monitor periodontal health. This has implications for potential misdiagnosis and failure to detect periodontitis at an early stage. Nicotine metabolites concentrate in the periodontal tissues and can have local effects as well as the potential to affect the systemic host response. Dentists are well placed to assess the smoking status of their young patients and have a role to play in the delivery of smoking cessation advice especially as it pertains to periodontal health. In this way the dental profession can also make a significant contribution to the general health and well being of our youth and future generations.

Comparison of interleukin-1 genotypes in two populations with aggressive periodontitis

The genetic association of interleukin-1 (IL-1) with periodontitis has been investigated in different populations. Failure to detect an association with IL-1 genotypes in European Caucasians with aggressive periodontitis (AGP) has recently been reported. No data from Central American Hispanics are available. The purpose of this explorative study was to study the association between IL-1 genotypes and AGP in two populations. Ninety-one subjects, 28 North European patients and 33 controls together with 16 Central American patients and 14 controls were included in the study according to validated radiographic and clinical criteria. Two polymorphisms, IL-1alpha G(+4845)-T and IL-1beta C(+3954)-T were analysed by means of polymerase chain reaction-restriction fragment length polymorphism. The association between presence of specific genotypes and disease status was estimated by the odds ratio. A logistic regression was also used in order to investigate whether the occurrence of the disease depends upon the combination of the IL-1A and IL-1B alleles in the population. A similar distribution of genotypes between patients and controls in both populations was detected. The frequency of allele 1 of the IL-1A gene was higher in patients of both populations compared with controls, however, no statistical significant differences were found between patients and controls.

Single-nucleotide polymorphism in the CD14 promoter and periodontal disease expression in a Japanese population

It has been reported that there is a relationship between a single-nucleotide polymorphism (SNP) in the promoter region of the CD14 gene at position -159 (C-->T) and infectious diseases. The aim of the present study was to test the hypthesis that expression of this SNP correlates with periodontal disease in a Japanese population. The CD14 genotype was determined in 163 subjects with periodontitis and in 104 age- and gender-matched control subjects without periodontitis. The genotype distribution and allele frequency within the periodontitis patients were not significantly different from those of control subjects. There was, however, a significant difference in the genotype distribution between young patients (< 35 yrs) and older patients (>/==" BORDER="0"> 35 yrs). These findings suggest that CD14 -159C/T polymorphism is not related to the development of periodontitis in a Japanese population, but that, within the periodontitis subjects, expression of the SNP may be related to early disease activity.

Herpesviral-bacterial interactions in aggressive periodontitis

BACKGROUND

Human cytomegalovirus, Epstein-Barr virus and herpesvirus co-infections occur with significantly higher frequency in actively progressing than in stable periodontitis sites of adolescents and young adults. Also, periodontal presence of cytomegalovirus and Epstein-Barr virus is associated with increased occurrence of subgingival Porphyromonas gingivalis, Bacteroides forsythus, Dialister pneumosintes, Prevotella intermedia, Prevotella nigrescens, Treponema denticola and Actinobacillus actinomycetemcomitans.

AIM

This article reviews the evidence linking herpesviruses to the development of aggressive periodontitis and suggests a potential mechanism for herpesviral acceleration of the periodontal disease process.

CONCLUSIONS

It seems to be a reasonable supposition that the etiopathogenesis of various types of aggressive periodontitis includes the combined action of herpesviruses and specific bacterial species. New vaccines and vaccination technologies that are being developed against herpesviruses warrant testing for their ability to induce a protective immune response against destructive periodontal disease. Clearly, the importance of combined herpesviral-bacterial infections and associated host responses in the development of periodontitis needs to be studied further.

Immunolocalization of inducible nitric oxide synthase in localized juvenile periodontitis patients

Localized juvenile periodontitis (LJP) is associated with a destruction of periodontal tissues and the presence of Actinobacillus actinomycetemcomitans (AA). Lipopolysaccharide (LPS) from AA was found to induce a significant macrophage production of nitric oxide (NO). Increased nitric oxide synthase (NOS) activity was found to be negatively correlated with the neutrophil chemotactic response. The aim of this study was to determine the occurrence and distribution of inducible NOS (iNOS) in human gingival tissue from LJP patients. The distribution of iNOS was assessed by monoclonal antibody against iNOS. Cellular markers (CD 3, CD 20, and CD 68) were used to determine the cellular origin of iNOS. The immunostaining revealed the appearance of iNOS in inflamed compared to noninflamed gingival tissues. Macrophages expressed high levels of iNOS that may cause some damage to the periodontal tissues. This study suggests that iNOS activity in macrophages may modify abnormalities of neutrophil function.

Enhanced neutrophil emigration and Porphyromonas gingivalis reduction following PGG-glucan treatment of mice

Periodontal disease is the consequence of a mixed Gram-negative infection in the gingival sulcus and has been associated with deficits in the neutrophil response. A novel, and heretofore untested, alternative approach to therapy is the use of biological-response modulators that enhance the neutrophil response. Poly-beta1-6-glucotriosyl-beta1-3-glucopyranose glucan (PGG-glucan) is an immunomodulator, derived from yeast, which specifically enhances neutrophil priming, phagocytosis and bacterial killing while failing to induce inflammatory cytokine expression. The hypothesis tested was that PGG-glucan could enhance host resistance to a Gram-negative periodontal pathogen, Porphyromonas gingivalis. Chambers were implanted subcutaneously in the dorsolumbar region of C57BL/6J mice and allowed to heal for 14 days. PGG-glucan was administered subcutaneously to one-half of the animals and saline to the other half. In the first set of experiments the chambers were inoculated with P. gingivalis (A7436) at 4 x 10 (6), 4 x 10 (7), and 4 x 10 (8) colony-forming units (CFU). In the second set of experiments the chambers were inoculated with 5 x 10 (8) CFU of either P. gingivalis or Streptococcus sanguis, a Gram-positive oral microbe that is not periodontopathic. Chambers were sampled over the following 2 weeks. The results demonstrated that: (1). bacterial CFU and neutrophils increased with increasing bacterial inoculum (P<0.02); (2). bacterial CFU were lower in the PGG-glucan-treated animals than in the saline controls (P<0.02); and (3). neutrophil counts were higher in the PGG-glucan-treated animals than in the saline controls (P<0.01). These results indicate that PGG-glucan significantly enhances neutrophil emigration and bacterial killing, thus decreasing the bacterial infection in this model system.

Associations of serum concentrations of IgG, IgA, IgM and interleukin-1beta with early-onset periodontitis classification and race

BACKGROUND

The significance of serum concentrations of various antibodies and cytokines in the pathogenesis of early-onset periodontitis (EOP) is not well understood. Recent reports suggest differences between young blacks and whites in certain humoral responses, regardless of periodontal status. This study was undertaken to compare the serum concentrations of IgG, IgA, IgM, and IL-1beta in EOP subjects with that of healthy controls, and to study the effect of race on these levels.

MATERIAL AND METHODS

This case-control study included 228 individuals, 19-25 years old who were selected from a larger population examined in the National Survey of Oral Health of United States Children in 1986/1987. The subjects were classified by their EOP status and they included 166 subjects with EOP and 62 healthy controls. Blood samples were used to assess the serum concentrations of IgG, IgM, IgA, IgG subclass, and IL-1beta.

RESULTS

The serum concentrations of IgG, IgG subclasses, IgA, and IgM in blacks were not significantly different in the generalized, localized and incidental EOP groups as compared to the healthy controls. The serum IL-1beta concentration was slightly and uniformly lower in the EOP groups than in the control group, although not statistically significant. Blacks had significantly higher serum concentrations of total IgG, and of IgG1, IgG2 and IgG3 than whites and Hispanics. Hispanics had significantly higher serum concentrations of IgM and IgG4 than whites and blacks. Hispanics also had a significantly higher serum concentration of IL-1beta than blacks.

CONCLUSIONS

Total antibody response in blacks is not associated with EOP classification. Race has a significant effect on serum antibody concentrations irrespective of disease classification, with blacks having significantly higher serum concentrations of IgG1, IgG2 and IgG3 than whites and Hispanics.

Infection-mediated early-onset periodontal disease in P/E-selectin-deficient mice

BACKGROUND

Retrospective and correlation studies suggest that early-onset periodontal disease may be due to a deficiency in phagocyte function, a pathogenic oral biofilm, and/or dysregulated gingival cytokine expression. Increased susceptibility to periodontal disease is therefore thought to result from multiple risk factors.

METHODS

We tested this hypothesis prospectively using P/E-selectin adhesion molecule deficient mice that mimic the human syndrome leukocyte adhesion deficiency II.

RESULTS

Our studies demonstrate that, in comparison to wild type animals, P/E-/- mice exhibit: spontaneous, early onset alveolar bone loss which is significant by 6 weeks of age; a 10-fold elevation in bacterial colonization of their oral cavities; and elevated gingival tissue levels of the bone resorptive cytokine IL-1alpha. Alveolar bone loss is completely prevented by prophylactic antibiotic therapy.

CONCLUSIONS

These experiments provide the first prospective evidence for the multiple risk factor hypothesis of periodontal disease, and validate the first animal model for early onset periodontitis in which both the microbiota and host response can be systematically manipulated. P/E-/- animals should be useful in testing the virulence of putative periodontal pathogens, in determining the role of host resistance factors in periodontitis, in exploring the proposed relationship(s) between infection mediated alveolar bone loss and systemic health disorders, and exploring their genetic relationships.

Flow-cytometric analysis of lymphocyte subsets and mCD14 expression in patients with various periodontitis categories

BACKGROUND

Membrane-bound CD14 (mCD14) is expressed mainly on circulating monocytes and tissue macrophages. It is one of the receptors, which act at the recognition of lipopolysaccharides by host cells. Periodontopathic bacteria result in activation of cellular and humoral immune responses.

AIM

The aim of the present study was to analyze the peripheral blood mCD14 concentrations as well as cell surface markers of lymphocyte subsets in periodontitis patients of various categories.

MATERIALS AND METHODS

Peripheral blood samples were obtained from 22 early onset periodontitis (EOP), 10 adult periodontitis (AP) patients and 13 systemically and periodontally healthy control subjects. Three-color flow cytometry and a panel of relevant monoclonal antibodies were used to determine the percent expression of various cell surface markers on peripheral blood mononuclear cells (PBMCs). The results were tested statistically by one-way variance analysis and Newman Keuls test.

RESULTS

No significant difference was observed between the study groups with regard to the relative counts of B-cells, T-cells, T-helper, T-cytotoxic/suppressor, activated T-cells and natural killer cells. EOP patients expressed significantly lower level of interleukin-2 receptor (IL-2R) when compared with AP patients (6.08% and 19.3% respectively) (p<0.05). The level of mCD14 in EOP patients (7.18%) was lower than that of AP patients (9.3%) and the control subjects (9.2%), but the differences were not statistically significant.

CONCLUSIONS

The low level of IL-2R in the EOP group may be interpreted as an insufficient responsiveness to the periodontopathogens, which may be ultimately related with the more severe tissue destruction. Though not significant, the reduced expression of mCD14 in EOP group may also be related with the immune system deficiencies in these patients.

Candidate genes as potential links between periodontal and cardiovascular diseases

Recent epidemiological associations between periodontal disease and cardiovascular disease have led to a search for biological mechanisms that explain the associations. Genetic factors that influence biological processes involved in both diseases represent one of the potential mechanisms that may link periodontitis and cardiovascular disease. At present, several candidate genes have been investigated in one of the diseases but not the other. Although there are limited data to support a specific candidate gene as the explanation for observed associations between the 2 diseases, a few candidates look promising. One candidate that influences inflammation, interleukin-1 gene polymorphisms, has been associated with periodontal disease and cardiovascular disease. This review will consider biological mechanisms and genes that may be reasonable candidates for an etiological mechanism that influences the clinical characteristics of both periodontal disease and cardiovascular disease.

Associations between serum antibody levels to periodontal pathogens and early-onset periodontitis

BACKGROUND

The role of antibodies to periodontal microorganisms in the development of periodontal tissue destruction is still unclear. The aim of this study was to investigate the association between serum levels of IgG, IgA, and IgM antibodies to 6 periodontal microorganisms and clinical subtypes of varying severity of early-onset periodontitis (EOP) in young African American adults.

METHODS

The study group consisted of 159 African Americans aged 19 to 25 years (mean 22 years) and included 97 cases with EOP and 62 controls with no clinical signs of EOP. These subjects were selected from a nationally representative sample of adolescents who received an oral examination as part of the National Survey of Oral Health of United States Children in 1986-1987. The group was examined clinically a second time 6 years later and blood samples were collected. Serum levels of IgG, IgA, and IgM reactive to Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Campylobacter rectus, Eikenella corrodens, and Fusobacterium nucleatum were assessed.

RESULTS

Serum levels of IgG and IgA antibody reactive to P. gingivalis and A. actinomycetemcomitans and IgA antibody to P. intermedia were significantly higher in generalized EOP cases compared to healthy controls. IgM antibody levels did not show any significant associations with EOP for any of the 6 bacterial species tested. There were no significant differences in antibody levels between controls and the 13 subjects in our study who were classified with localized EOP.

CONCLUSIONS

The findings suggest that antibodies to P. gingivalis, P. intermedia, and A. actinomycetemcomitans may play a significant role in the pathogenesis of EOP. Substantial longitudinal studies that monitor antibody levels and avidity prior to disease onset, during progression, and following clinical intervention will be necessary to fully understand the role of this component of the immune response in protection versus tissue destruction and the potential use in EOP risk assessment and disease management.

Heterogeneity of host immunological risk factors in patients with aggressive periodontitis

BACKGROUND

The pathogenesis of early-onset periodontitis (EOP) can be explained by various host risk factors. Previous studies have focused on a single (among many possible) immunological risk factor and the association among the factors has not been assessed. We comprehensively investigated the associations among multiple host immunological risk factors in EOP patients to further elucidate their role in the pathogenesis of EOP.

METHODS

Sixty-eight EOP patients (50 generalized EOP, 18 localized EOP), 51 EOP-suspected patients (S-EOP), 43 adult periodontitis (AP) patients, and 36 periodontally healthy subjects (HS) participated in this cross-sectional study. We examined peripheral neutrophil functions, phenotypic and functional characterization of peripheral lymphocytes (lymphocyte subsets, T-cell proliferative activity), cytokine productivity (interleukin [IL]-1, IL-2, tumor necrosis factor [TNF]-alpha, interferon [IFN]-gamma, IL-4 and IL-6), serum immunoglobulin G (IgG) antibody titers against 12 periodontal bacteria, and HLA class II genotypes.

RESULTS

G-EOP, S-EOP, and AP patient groups showed significantly lower percentages of pan T cells and CD8-positive cells (P < 0.02) compared with the HS group. L-EOP patients showed depressed IL-4 and TNF-alpha productivity compared with the HS group (P < 0.02). The EOP group showed significantly elevated antibody levels against Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, and Fusobacterium nucleatum compared with the HS group (P < 0.05). The frequency with DQB1*0503 was significantly higher in the EOP patient group than the HS group (P = 0.045) due to the higher frequency in L-EOP patients than the HS group (P = 0.035). There were wide interindividual variations in each of the tests among patient and HS groups; however, EOP patients showed wider intradiagnostic group variations in certain host defensive cell functions than the other groups. There were some EOP patients who showed extremely low or high values in some tests; the EOP patients could be further divided into subgroups according to their host defensive and immunological profiles. However, there was heterogeneity in some of the other host immunological tests even in the subgroups.

CONCLUSIONS

The association of host immunological risk factors in EOP patients is widely varied and more complex than previously thought. These results indicate the difficulty of explaining the pathogenesis of EOP based on a single host risk factor and also emphasize the importance of critical assessment of not only EOP patient groups, but also individual patients.

Some local and systemic immunological features of prepubertal periodontitis

OBJECTIVES

The aim of the present investigation was to study local (gingival) and systemic host defense characteristics in a sample of children exhibiting local prepubertal periodontitis (LPP).

MATERIAL AND METHODS

2 groups of subjects were included in the present study. One group consisted of 11 children (9.5+/-2.0 years) with signs of periodontal disease (LPP group). A 2nd group comprised 21 adults (48.1+/-5.8 years) with advanced periodontal disease: adult periodontitis (AP) group. Gingival biopsies and a sample of peripheral blood were obtained in each individual of the AP group and in 7 out of the 11 subjects in the LPP group. The biopsies were prepared for morphometrical and immunohistochemical analysis and the blood samples prepared for immunohistochemical analysis.

RESULTS

The cellular infiltrates in the biopsies of the LPP group contained a larger proportion of lymphocytes and, in particular B cells, than was the case in the AP group. The TCR Valpha/Vbeta gene expression in the lesions in the AP group was dominated by Vbeta 17 and in the LPP group by Valpha2. The content in peripheral blood of various lymphocyte sub-populations and TCR Valpha/Vbeta gene expression in the 2 groups was almost similar.

CONCLUSION

It is suggested that (i) the systemic host response in children with prepubertal periodontitis has many features in common with that seen in adult patients but that (II) local defense mechanisms in the periodontitis lesion of LPP differ from those in adult periodontitis.

A multidisciplinary approach to the diagnosis and treatment of early-onset periodontitis: a case report

BACKGROUND

The diagnosis and treatment of early-onset forms of periodontitis (EOP) represent a major challenge to periodontists. In this case report, we describe a multidisciplinary approach for the treatment of a patient with severe generalized juvenile periodontitis (GJP). Our approach incorporates clinical laboratory evaluation with conventional concepts of periodontal pathogenesis and therapeutics to diagnose and effectively treat EOP.

METHODS

The 17-year-old female patient presented with clinical and radiographic evidence of severe attachment loss. Microbiological testing showed the presence of known periodontal pathogens including Actinobacillus actinomycetemcomitans, Prevotella intermedia, and Porphyromonas gingivalis. Routine immunological tests did not reveal any of the functional defects thought to play a role in the pathogenesis of EOP After initiation of therapy, which consisted of scaling and root planing, supplemented with administration of systemic antibiotics, a reduction in probing depth and gain in clinical attachment could be demonstrated. Microbiological testing was used to monitor the composition of the periodontal microbiota and to adjust antimicrobial therapy accordingly.

RESULTS

Using a non-surgical approach to treatment, except for 2 root amputations performed without flap reflection, we have been able to stabilize this patient's periodontal condition over the course of a 2-year follow-up period.

CONCLUSIONS

This treatment strategy provides an efficacious alternative to more aggressive forms of therapy and should therefore be considered for the treatment of patients with severe EOP.

Toll-like receptor 4-deficient mice have reduced bone destruction following mixed anaerobic infection

C3H/HeJ mice have an impaired ability to respond to lipopolysaccharide (LPS) due to a mutation in the gene that encodes Toll-like receptor 4 (TLR4). The effect of TLR4 deficiency on host responses to endodontic infections is unknown. In the present study, we compared periapical bone destruction, sepsis, and inflammatory cytokine production in LPS-hyporesponsive C3H/HeJ and wild-type control C3H/HeOuJ mice. The mandibular first molars of both strains were subjected to pulpal exposure and infection with a mixture of four anaerobic pathogens, Prevotella intermedia, Fusobacterium nucleatum, Streptococcus intermedius, and Peptostreptococcus micros. At sacrifice on day 21, TLR4-deficient C3H/HeJ mice had significantly reduced periapical bone destruction compared to wild-type C3H/HeOuJ mice (P < 0.001). The decreased bone destruction in C3H/HeJ correlated with reduced expression of the bone resorptive cytokines interleukin 1alpha (IL-1alpha) (P < 0.01) and IL-1beta (P < 0.05) as well as the proinflammatory cytokine IL-12 (P < 0.05). No significant differences were seen in the levels of gamma interferon, tumor necrosis factor alpha (TNF-alpha), or IL-10 between the two strains. The expression of IL-1alpha, IL-1beta, TNF-alpha, IL-10, and IL-12 were all significantly reduced in vitro in macrophages from both TLR4-deficient C3H/HeJ and C57BL/10ScNCr strains, compared to wild-type controls. Notably, the responses of TLR4-deficient macrophages to both gram-positive and gram-negative bacteria were similarly reduced. Neither C3H/HeJ nor C3H/HeOuJ mice exhibited orofacial abscess development or infection dissemination as determined by splenomegaly or cachexia. We conclude that intact TLR function mediates increased proinflammatory responses and bone destruction in response to mixed anaerobic infections.

Human herpesviruses and Porphyromonas gingivalis are associated with juvenile periodontitis

BACKGROUND

Although herpesviruses have been associated with adult periodontitis, their relationship with juvenile periodontitis (JP) has not been established. This case-control study examined possible associations between JP and pathogenic bacteria, the human cytomegalovirus (HCMV), and the Epstein-Barr type 1 virus (EBV-1).

METHODS

Subjects were participants in a larger survey of schoolchildren in North-Central Jamaica. Subgingival plaque samples from 15 subjects with JP, 20 with incipient periodontitis (IP), and 65 randomly-selected healthy controls were assayed for Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans using a 16S rRNA polymerase chain reaction (PCR) identification method, and for HCMV and EBV-1 using nested PCR identification.

RESULTS

Strong bivariate associations were found between JP and P. gingivalis (odds ratio [OR] = 12.7; 95% CI = 2.6, 61.4), HCMV (OR = 10.0; 95% CI = 2.7, 36.3), and A. actinomycetemcomitans (OR = 8.0; 95% CI = 2.3, 27.5), but not EBV-1. In multivariate analyses, P. gingivalis remained a significant explanatory variable (OR = 7.8; 95% CI = 1.5, 40.9); however, the associations were marginal for HCMV (OR = 4.6; 95% CI = 0.9, 22.7), and non-significant for A. actinomycetemcomitans (OR = 2.0; 95% CI = 0.4, 9.7). The associations with JP and the extent of attachment loss were even stronger when both P. gingivalis and HCMV were detected together. P. gingivalis (OR = 3.9; 95% CI = 1.3, 12.0) and EBV-1 (OR = 3.3; 95% CI = 1.0, 10.3) were the only significant explanatory variables in the multivariate analysis of IP.

CONCLUSIONS

P. gingivalis is the strongest and most stable indicator of periodontitis in Jamaican adolescents. Co-infection with P. gingivalis and HCMV appears to be particularly deleterious to periodontal health.

Early-onset periodontitis

In 1993, the 1st European Workshop on Periodontology explicitly recognized that there was insufficient knowledge to differentiate truly different forms of periodontal disease from differences in the presentation/severity of the same disease. In spite of recent progress in our understanding of periodontal diseases, the issue is far from having been resolved. Classification of periodontal diseases, therefore, remains based upon the definition of specific clinical syndromes. Early-onset periodontitis (EOP) is one such syndrome and comprises a group of pathological conditions leading to loss of periodontal tissues early in life. The notion that classifies periodontitis syndromes as "early-onset" or "adult" is primarily epidemiological in nature and is based on the observation that periodontitis is rather infrequent in children and young adults. Nevertheless, considerable epidemiological evidence indicates that periodontitis does affect children and young adults to a level of severity that may lead to premature exfoliation of primary and/or permanent teeth. Clinical presentation of periodontitis early in the life of an individual is thought to indicate that the etiologic agents have been able to cause considerable tissue damage over a relatively short period of time. It also implies either infection with highly virulent bacteria and/or a highly susceptible subject. The purpose of this review is to discuss the criteria generally utilized to classify EOP, provide the rationale to designate EOP as a distinct disease entity, and to review the evidence justifying a subclassification into particular subgroups of EOP.

The pathogenesis of periodontal diseases

This informational paper was prepared by the Research, Science, and Therapy Committee of The American Academy of Periodontology, and is intended for the information of the dental profession. The purpose of the paper is to provide an overview of current knowledge relating to the pathogenesis of periodontal diseases. The paper will review biological processes thought to provide protection against periodontal infections. It will further discuss the mechanisms thought to be responsible for both overcoming and subverting such protective mechanisms and those that lead to destruction of periodontal tissues. Since an understanding of pathogenic mechanisms of disease is one foundation upon which new diagnostic and therapeutic modalities are based, the practitioner can use this information to help make decisions regarding the appropriate application of such new modalities in patient care settings.