Coordinate production of PGE2 and IL-1 beta in the gingival crevicular fluid of adults with periodontitis: its relationship to alveolar bone loss and disruption by twice daily treatment with ketorolac tromethamine oral rinse

High-fat diet-induced metabolic syndrome increases ligature-induced alveolar bone loss in mice

BACKGROUND

It has been well documented that metabolic syndrome (MetS) increases severity of periodontitis. In this study, we determined the effect of high-fat diet (HFD)-induced MetS on alveolar bone loss in a mouse model with ligature-induced periodontitis. To understand how MetS increases bone loss, we tested our hypothesis that palmitic acid (PA), a most abundant saturated fatty acid in the HFD, interacts with lipopolysaccharide (LPS) to promote osteoclastogenesis.

METHODS

We induced MetS by feeding mice HFD for 18 weeks and induced periodontitis with ligature placement. After treatments, we assessed alveolar bone loss using micro-computed tomography and determined osteoclastogenesis using tartrate-resistant acid phosphatase (TRAP) staining. To explore the mechanisms, we treated macrophages with PA, LPS or both and analyzed the osteoclast formation and cytokine expression in macrophages.

RESULTS

While ligature robustly induced periodontitis in mice with or without MetS, the mice with MetS had more bone loss than those without MetS. PA and LPS cooperatively induced osteoclast formation and stimulated the expression of inflammatory cytokines involved in osteoclastogenesis potentially via a FAT/CD36-dependent mechanism in macrophages.

CONCLUSIONS

HFD-induced MetS increases alveolar bone loss in mice with ligature-induced periodontitis, and PA and LPS cooperatively stimulate osteoclast formation and proinflammatory gene expression in macrophages.

Correlation between interleukin-1β and matrix metalloproteinase-1 levels in crevicular fluid with a proposed periodontal disease index in children

Background:

The crevicular fluid contains biomarkers that allow the identification of periodontal disease, anticipation of its risk, and prediction of its progression.

Purpose:

The purpose of this study is to correlate interleukin-1β (IL-1β) and matrix metalloproteinase-1 (MMP-1) levels in crevicular fluid with periodontal disease severity in schoolchildren.

Methods:

A cross-sectional study was conducted in 82 schoolchildren between 9 and 12 years. The biofilm percentage, attachment level, gingival recession, dental calculus, and bleeding on probing were measured in the teeth 16, 26, 36, 41, and 46. These five parameters obtained were considered to propose a disease score between 0 and 10 points. In crevicular fluid from the tooth with the highest score, IL-1β and MMP-1 levels were measured.

Results:

According to the proposed score, mild gingivitis was identified in 20 schoolchildren, moderate gingivitis in 30, and severe gingivitis in 32. Biofilm percentage, IL-1β, and MMP-1 levels increased as the severity of the disease increase. The mean and 95% confidence interval were 23.2 pg/μl (18.6–27.7), 37.3 pg/μl (27.8–46.9), and 44.6 pg/μl (34.4–58.8) (P = 0.01) for IL-1β and 2.69 mol/min (2.51–2.87), 4.43 mol/min (3.9–4.95), and 5.59 mol/min (4.81–6.38) (P < 0.001) for MMP-1 in each group, respectively. The proposed clinical score correlated with biofilm percentage (r = 0.63), IL-1β (r = 0.50), and MMP-1 (0.45) levels, P < 0.001 in all cases.

Conclusions:

The proposed clinical score for periodontal disease in children correlated with percentage of biofilm, IL-1β, and MMP-1 levels.

Comparison of Clinical, Radiographic, and Immunologic Inflammatory Parameters around Crestally and Subcrestally Placed Dental Implants: 5-Year Retrospective Results

PURPOSE

To compare changes in clinical (bleeding on probing [BOP] and probing pocket depth [PPD]), radiographic (crestal bone loss [CBL]), and immunologic inflammatory (interleukin-1beta [IL-1β] and matrix metalloproteinase-9 [MMP-9]) parameters around crestally and subcrestally placed dental implants 5 years after implant placement.

MATERIALS AND METHODS

Fifty-two patients were divided into 2 groups: group 1 (n = 27): patients with single implants placed approximately 2 mm below the alveolar crest; group 2 (n = 25): patients with single implants placed at bone level. In both groups, peri-implant BOP, PPD, and CBL were measured, and levels of IL-1β and MMP-9 were determined in duplicates using enzyme-linked immunosorbent assay. Full-mouth debridement was performed biannually in both groups. Statistical analysis was performed using the Mann-Whitney U test (significance set at p < 0.05).

RESULTS

All measurements in groups 1 and 2 were performed 5.3 ± 0.2 and 5.2 ± 0.1 years after implant placement, respectively. The mean CBL was 1.2 ± 0.2 mm and 1.4 ± 0.2 mm in groups 1 and 2, respectively. There was no significant difference in mean BOP, PPD, CBL and in levels of IL-1β, and MMP-9 among implants in both groups.

CONCLUSION

Clinical, radiographic, and immunologic inflammatory parameters are comparable around crestally and subcrestally placed single dental implants up to 5 years after placement. The depth of implant placement appears to have no effect on clinical status and performance of single dental implants.

Inhibition of microsomal prostaglandin E synthase-1 by aminothiazoles decreases prostaglandin E2 synthesis in vitro and ameliorates experimental periodontitis in vivo

The potent inflammatory mediator prostaglandin E2 (PGE2) is implicated in the pathogenesis of several chronic inflammatory conditions, including periodontitis. The inducible enzyme microsomal prostaglandin E synthase-1 (mPGES-1), catalyzing the terminal step of PGE2 biosynthesis, is an attractive target for selective PGE2 inhibition. To identify mPGES-1 inhibitors, we investigated the effect of aminothiazoles on inflammation-induced PGE2 synthesis in vitro, using human gingival fibroblasts stimulated with the cytokine IL-1β and a cell-free mPGES-1 activity assay, as well as on inflammation-induced bone resorption in vivo, using ligature-induced experimental periodontitis in Sprague-Dawley rats. Aminothiazoles 4-([4-(2-naphthyl)-1,3-thiazol-2-yl]amino)phenol (TH-848) and 4-(3-fluoro-4-methoxyphenyl)-N-(4-phenoxyphenyl)-1,3-thiazol-2-amine (TH-644) reduced IL-1β-induced PGE2 production in fibroblasts (IC50 1.1 and 1.5 μM, respectively) as well as recombinant mPGES-1 activity, without affecting activity or expression of the upstream enzyme cyclooxygenase-2. In ligature-induced experimental periodontitis, alveolar bone loss, assessed by X-ray imaging, was reduced by 46% by local treatment with TH-848, compared to vehicle, without any systemic effects on PGE2, 6-keto PGF1α, LTB4 or cytokine levels. In summary, these results demonstrate that the aminothiazoles represent novel mPGES-1 inhibitors for inhibition of PGE2 production and reduction of bone resorption in experimental periodontitis, and may be used as potential anti-inflammatory drugs for treatment of chronic inflammatory diseases, including periodontitis.

Interleukin-1 gene polymorphisms and chronic periodontitis in adult whites: a systematic review and meta-analysis

BACKGROUND

Interleukin-1 (IL-1) gene polymorphisms have been associated with increased levels of inflammatory mediators and several inflammatory diseases. Periodontitis is a bacterially induced chronic inflammatory disease that destroys the connective tissues and bone that support the teeth, affects substantial numbers of adults, and has been implicated as a contributing factor in systemic diseases. IL-1 gene polymorphisms, most prominently IL1A (-889), IL1A (+4845), and IL1B (+3954), have been associated with chronic periodontitis (CP) in whites. Since the first report, ≥125 studies have examined IL-1 gene variation in relation to periodontal disease. These studies have produced mixed findings in diverse periodontal phenotypes and in different ethnic groups. One previous meta-analysis has been published on this topic and supported an association between IL-1 genes and periodontitis, but considerable doubt remains about the patient populations in which the association may be of clinical relevance.

METHODS

A systematic review and meta-analysis was conducted in an attempt to clarify whether IL-1 gene variants were associated with well-defined clinical phenotypes of CP in white patients. Study inclusion criteria focused on the analytic framework originally proposed for the IL-1 genetic effect in which overexpression of inflammatory mediators is hypothesized to result in more severe periodontitis in response to a bacterial challenge.

RESULTS

Twenty-seven studies were included in the qualitative analysis. Nineteen studies yielded significant associations between carriage of the minor IL-1 alleles and periodontitis. The meta-analysis, based on 13 qualifying studies, found significant effects for the two individual gene variations (IL1A odds ratio [OR] = 1.48; IL1B OR = 1.54) and for a composite genotype that combines minor alleles at each locus (OR = 1.51). Statistically significant heterogeneity was found that could not be explained, but there was no indication of publication bias.

CONCLUSION

This review and meta-analysis show that IL1A and IL1B genetic variations are significant contributors to CP in whites.

Accumulation of topical naproxen by cultured oral epithelium

Topically administered non-steroidal anti-inflammatory drugs (NSAIDs) inhibit periodontal bone loss, but little is known about the mechanism by which they penetrate oral epithelium. Active transporters could potentially play a role in this process. In this study, we used a cell line derived from oral epithelium to investigate a role for transporters and to characterize conditions that enhance epithelial penetration. Using fluorescence to monitor uptake, we demonstrated that SCC-25 cell monolayers transport naproxen with a Michaelis constant (K(m)) and maximum velocity (V(max)) of 164 microg/mL and 0.94 ng/min/microg protein, respectively. At steady state, the intra-cellular/extracellular concentration ratio was 3.4. Naproxen accumulation was more efficient at acidic pH than under neutral or alkaline conditions. Small proportions of glycerol, Pluronic F-127, and glucosylceramide enhanced naproxen entry. The individual and combined effects of glycerol and Pluronic F-127 were of lesser magnitude than those obtained with glucosylceramide or at pH 6.3. Thus, SCC-25 cells possess transporters for naproxen.

Anti-inflammatory effects of Lactobacillus brevis (CD2) on periodontal disease

OBJECTIVES

To analyze the anti-inflammatory effects of Lactobacillus brevis extracts on periodontitis patients and to investigate the involved mechanisms in vitro on activated macrophages.

METHODS

Eight healthy subjects and 21 patients with chronic periodontitis were enrolled to analyze the effect of L. brevis-containing lozenges on periodontitis-associated symptoms and signs. Before and after the treatment, the patients received a complete periodontal examination. Saliva samples, collected before and after treatment, were analyzed for metalloproteinase and nitric oxide synthase (NOS) activity, immunoglobulin-A (IgA), prostaglandin E(2) (PGE(2)) and gamma-interferon (IFN-gamma) levels. Arginine deiminase (AD) and NOS activities were determined through a radiometric assay. Metalloproteinases were assayed by zymogram and Western blotting, whereas IgA, PGE(2) and IFN-gamma were assayed by enzyme-linked imunosorbent assay tests.

RESULTS

The treatment led to the total disappearance or amelioration of all analyzed clinical parameters in all patients. This was paralleled to a significant decrease of nitrite/nitrate, PGE(2), matrix metalloproteinase, and IFN-gamma levels in saliva samples.

CONCLUSION

Our results suggest that the anti-inflammatory effects of L. brevis could be attributed to the presence of AD which prevented nitric oxide generation. Our findings give further insights into the knowledge of the molecular basis of periodontitis and have a potential clinical significance, giving the experimental ground for a new innovative, simple and efficacious therapeutical approach of periodontal disease.

Gingival crevicular fluid interleukin-1?, prostaglandin E2and periodontal status in a community population

AIM

Interleukin-1 beta (IL-1beta) and prostaglandin E(2) (PGE(2)) are key inflammatory mediators involved in periodontal disease. The purposes of this molecular cross-sectional epidemiological study were to investigate relationships in a community sample between mean concentrations of IL-1beta and PGE(2) in gingival crevicular fluid (GCF) and (1) clinical periodontal signs and (2) risk factors of host inflammatory response and/or periodontal disease.

MATERIAL AND METHODS

The sample comprised 6277 community-dwelling adults aged 52-74 years enrolled in the Atherosclerosis Risk in Communities (ARIC) study. IL-1beta and PGE(2) concentrations were measured using enzyme-linked immunosorbent assay. Person-level summary variables were computed for maximum pocket depth (MaxPD), maximum clinical attachment level (MaxCAL) and presence/absence of bleeding on probing (BOP). Mean GCF IL-1beta and PGE(2) concentrations were dependent variables in multiple linear regression models with periodontal measures and covariates as explanatory variables.

RESULTS

Both GCF IL-1beta and PGE(2) were positively related to MaxPD and BOP in multiple regression models (p<0.01). Increased levels of IL-1beta and PGE(2) were associated with body mass index >or=30 kg/m(2).

CONCLUSION

Higher levels of GCF IL-1beta and PGE(2) were significantly associated with clinical signs of periodontal disease and independently related to patient-based anthropomorphic measures, behaviours and exposures in community-dwelling adults.

Host response modulation in the management of periodontal diseases

OBJECTIVE

To review the biological mechanisms and clinical utility of therapeutic modulation of the host response in the management of periodontal diseases.

MATERIAL AND METHODS

A search of MEDLINE-PubMed was performed up to and including December 2004. The search was limited to in vitro, experimental animal and clinical studies published in English. The selection criteria included all levels of available evidence: systematic reviews, randomised-controlled clinical trials, controlled clinical trials, prospective and retrospective cohort studies and case reports of human and experimental animal studies.

RESULTS

Six targets for non-microbial chemotherapeutic intervention were identified. Clinical trials have demonstrated the ability of non-steroidal anti-inflammatory drugs to slow periodontal disease progression. However, recently reported serious adverse effects preclude the use of cyclooxygenase-2 inhibitors as an adjunct to periodontal therapy. Adjunctive use of subantimicrobial dose doxycycline to non-surgical periodontal therapy is beneficial in the management of chronic periodontitis over 12 months. Controversial data exist on the effects of bisphosphonate administration as an adjunct to periodontal therapy. Evidence on modulation of other host mediators including lipoxins, cytokines and nitric oxide synthase is limited to animal research.

CONCLUSION

After validation in long-term clinical trials, adjunctive host modulation therapy may prove advantageous in the management of periodontal diseases.

Effects of experimental gingivitis on crevicular PGE2 in a split mouth trial

OBJECTIVE

The study aimed to analyse the effects of experimental gingivitis on crevicular prostaglandin E(2) (PGE(2)). An increase of PGE(2) was expected.

METHODS

Fourteen medical students refrained for 28 days from any oral hygiene procedures in two antagonistic quadrants while they maintained close to perfect oral hygiene in the remaining quadrants. Crevicular fluid samples were taken at baseline and at days 7, 14, 21 and 28 of experimental gingivitis both from quadrants with and without oral hygiene. PGE(2)-concentrations (ng/ml) and absolute levels (pg/sample) were analysed for quadrants with and without oral hygiene.

RESULTS

Comparison of quadrants with and without oral hygiene by repeated measures anova revealed no effects of experimental gingivitis both on crevicular PGE(2)-concentrations and absolute levels.

CONCLUSION

The study does not support the notion that experimental gingivitis induces an increase of crevicular PGE(2). The data are discussed in the context of other studies on PGE(2) concentrations in gingivitis. Close inspection of these studies reveals no clear evidence for an increase of local PGE(2) in gingivitis.

Randomized, Double-Blind, Placebo-Controlled Phase IIB Trial of the Cyclooxygenase Inhibitor Ketorolac as an Oral Rinse in Oropharyngeal Leukoplakia

PURPOSE

Nonselective cyclooxygenase (COX) inhibitors have been reported to decrease the frequency of upper aerodigestive cancers. Ketorolac tromethamine oral rinse has been shown to resolve another COX-dependent process, periodontal disease, without incurring gastrointestinal side effects. This trial evaluated if a topically delivered oral rinse containing ketorolac was as safe as and more effective than oral rinse alone in reducing the area of oral leukoplakia.

EXPERIMENTAL DESIGN

57 patients were randomized (2:1 ratio) in a double-blind, placebo-controlled study of ketorolac (10 ml of a 0.1% ketorolac rinse solution; n = 38) or placebo (10 ml of rinse solution; n = 19) given twice daily for 30 s over 90 days. Primary end point was evaluated visually obtaining bidimensional measurement of the size of leukoplakia lesion(s) at entry and at 90 days. Secondary end point was histological assessment of the leukoplakia as sampled by serial punch biopsy and independently reviewed by three pathologists.

RESULTS

The patients included 67% males, 11% non-Caucasian, and 86% used tobacco with no significant differences between the two arms. Both rinses were well tolerated with good compliance, and there was no significant difference in adverse events (P = 0.27). Major response rate (complete response and partial response) was 30% for ketorolac and 32% for the placebo arm. There was no significant difference in change in histology between the two arms.

CONCLUSION

Local delivery of a COX-containing oral rinse was well tolerated but produced no significant reduction in the extent of leukoplakia compared with the placebo. However, the favorable response rate to placebo arm remains unexplained and additional investigation of the tissue penetration with ketorolac is warranted.

Periodontal host modulation with antiproteinase, anti-inflammatory, and bone-sparing agents. A systematic review

BACKGROUND

The use of modulating agents, including inhibition of matrix metalloproteinases (MMPs) with antiproteinases, blocking production of proinflammatory cytokines and prostaglandins with anti-inflammatory drugs, and inhibiting activation of osteoclasts with bone-sparing agents, has been postulated to be of therapeutic value as an adjunctive therapy to the management of chronic periodontitis.

RATIONALE

The objective of this systematic review of the literature was to assess the adjunctive efficacy of antiproteinase, anti-inflammatory, and bone-sparing host-modulating agents in the treatment of gingivitis, aggressive periodontitis, and chronic periodontitis. FOCUSED QUESTIONS: 1. In patients with periodontal diseases, what is the effect of host-modulation agents, alone or combined with conventional therapy, compared to conventional therapy alone as assessed by clinical, radiographic, adverse, and patient-centered outcomes? 2. In patients with dental implants, what is the effect of host-modulation agents on implant success assessed by clinical, radiographic, adverse, and patient-centered outcomes?

SEARCH PROTOCOL

MEDLINE, Embase, and the Cochrane Library databases were searched without language restrictions through April 1, 2002 for studies that used tetracycline (TET)-related matrix metalloproteinase (MMP) inhibitors, or non-steroidal anti-inflammatory drugs (NSAIDs) and bisphosphonate anti-osteolytic agents. The investigation also included hand searching of journals and contacting authors and industry experts.

SELECTION CRITERIA

INCLUSION CRITERIA

Only human studies (randomized controlled clinical trials, cohort studies, case-control studies, cross-sectional studies, and case series) were selected. Studies were on subjects with gingivitis, aggressive or chronic periodontitis, or dental implants. Interventions included TET-related MMP inhibitors, NSAIDs, or bisphosphonate anti-osteolytic agents.

EXCLUSION CRITERIA

Studies that used MMP tissue inhibitors as diagnostic or prognostic indicators of periodontal disease or that evaluated short-term systemic antibodies or locally delivered levels of drugs with antiproteinase activity were excluded.

DATA COLLECTION AND ANALYSIS

The primary outcomes for assessment were changes in bone or clinical attachment levels (CAL); secondary outcomes included clinical measures of plaque, gingival inflammation, probing depth (PD), and mobility. Summary data appropriate for meta-analysis were pooled using a weighted average and analyzed using a standardized difference; the results were checked with both fixed-effects and random-effects models.

MAIN RESULTS

1. A meta-analysis done on the studies reporting changes in CAL and PD following administration of sub-antimicrobial doses of doxycycline (SDD) in conjunction with scaling and root planing (SRP) in patients with periodontitis showed a statistically significant beneficial adjunctive effect. 2. There were insufficient data to provide meta-analyses on periodontal patients treated with other host-modulating agents; descriptive tables are included. 3. NSAIDS show promise in their ability to slow periodontal disease. 4. Preliminary data on bisphosphonate agents indicate there is a potential role for these agents in periodontitis management. 5. There are a very limited number of studies on host-modulating agents and dental implants and no analyses were possible. 6. Because the treatment methodologies and clinical variables differed considerably among the studies, it is difficult to summarize the information and identify a reliable total patient population.

REVIEWERS' CONCLUSIONS

1. Large multi-center trials are needed to evaluate the role of host-modulating agents in the treatment of periodontitis. 2. NSAIDS and bisphosphonate drugs may have a potential adjunctive role in periodontal therapy. 3. The adjunctive use of SDD with SRP is statistically more effective than SRP alone in reducing PD and in achieving CAL gain.

Interleukin-1beta induces matrix metalloproteinase-1 expression in cultured human gingival fibroblasts: role of cyclooxygenase-2 and prostaglandin E2

OBJECTIVE

Matrix metalloproteinases (MMPs) degrade extracellular matrices and are responsible for excessive connective tissue breakdown in inflammatory disorders. We investigated the mechanism of MMP-1 expression in human gingival fibroblasts in response to the stimulation with interleukin-1beta (IL-1beta), and the role of inducible-type cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2) in the regulation of MMP-1 expression.

MATERIALS AND METHODS

We stimulated cultured human gingival fibroblasts with r(h)IL-1beta, and examined the expression of MMP-1 mRNA and protein by quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. The effect of indomethacin, dexamethasone, or cycloheximide (CHX) on the IL-1beta-induced expression of MMP-1 was examined. The expression of MMP-1 in gingival fibroblasts stimulated with PGE2 was also examined.

RESULTS

IL-1beta stimulated the expressions of mRNA and protein for MMP-1, in cultured fibroblasts, in time- and concentration-dependent manners. Pretreatment of the cells with indomethacin or dexamethasone inhibited the IL-1beta-induced MMP-1 expression. CHX, a protein synthesis inhibitor, also suppressed the MMP-1 expression. IL-1beta also induced COX-2 expression in gingival fibroblasts, and PGE2, a major COX-2 product, was found to enhance MMP-1 expression.

CONCLUSION

The IL-1beta-induced MMP-1 expression in gingival fibroblasts may be mediated, at least in part, by COX-2 and its product PGE2.

The overexpression of cyclo-oxygenase-2 in chronic periodontitis

BACKGROUND

The objective of this prospective cross-sectional study was to determine if cyclo-oxygenase-2, or COX-2, is overexpressed in the inflamed gingival tissue of patients diagnosed as having moderate-to-severe chronic periodontitis, or CP.

METHODS

The authors evaluated clinical measures, crevicular fluid and gingival biopsy specimens from patients with moderate or severe CP (n = 16) and from healthy volunteers (n = 8). Patients were diagnosed as having CP based on clinical attachment loss, or CAL, of at least 5 millimeters at two sites in each quadrant and on evidence of alveolar bone loss as assessed from standard periapical or bite-wing radiographs. Healthy patients exhibited no sites with CAL of more than 2 mm and no evidence of alveolar bone loss. The authors used standard techniques to perform biochemical measures.

RESULTS

Levels of interleukin-1 beta, or IL-1beta, in crevicular fluid were more than doubled in the CP group (P < .05). The amounts of COX-2 mRNA and protein also were elevated in gingival tissues from subjects with CP compared with those from healthy subjects. To gain further mechanistic insights, the authors conducted in vitro studies. The results showed that lipopolysaccharide and tumor necrosis factor alpha, or TNF-alpha, induced COX-2 in macrophages, while IL-1beta and TNF-alpha induced COX-2 in oral epithelial cells.

CONCLUSIONS

Taken together, these results suggest that levels of COX-2 in gingivae reflect clinical measures of periodontitis and gingival inflammation.

CLINICAL IMPLICATIONS

The discovery of increased levels of COX-2 in inflamed gingival tissue suggests that COX-2 represents a pharmacological target for the prevention or treatment of CP.

Effects of plaque, psychological stress and gender on crevicular Il-1beta and Il-1ra secretion

OBJECTIVES

The study aimed to analyse (a) whether the effects of psychological stress and of experimental gingivitis on interleukin-1beta (Il-1beta) described before are compensated by concomitant increases in Il-1 receptor antagonist (Il-1ra), and (b) whether there do exist any gender differences in the Il-1 responses to experimental gingivitis and to psychological stress.

MATERIALS AND METHODS

Thirteen medical students participating in a major academic exam (seven males, six females) and 14 medical students without academic stress (eight males, six females) refrained from oral hygiene in two antagonistic quadrants for 28 days (plaque) while they maintained oral hygiene in the remaining quadrants (hygiene). Weekly crevicular fluid samples of plaque and hygiene sites were assayed for Il-1beta and Il-1ra.

RESULTS

Neither stress nor experimental gingivitis exerted significant effects on Il-1ra. In controls, we observed significant gender and gender x time effects on Il-1beta; comparing stress groups, gender x time and stress x gender x time interactions became significant. Women show a reduced Il-1beta response to plaque at rest and an increased response under stress. Similar results were found with respect to bleeding on probing.

CONCLUSIONS

Gender must be controlled in studies on periodontal responses to pathogens. Stress plays a role in these responses.

Effects of academic stress on oral hygiene - a potential link between stress and plaque-associated disease?

BACKGROUND

While there seems to be a common belief that psychosocial stress affects oral hygiene behavior, this assumption has rarely been proved. The present study thus aims to analyse stress effects on oral hygiene.

MATERIAL AND METHODS

16 matched pairs of medical students each consisting of 1 student participating in a major academic exam and 1 control without current academic stress, were formed on the basis of baseline plaque levels. At baseline, a professional tooth cleaning was performed. On the last day of exams, students answered questionnaires about oral hygiene during the exams and were afterwards asked to attend for a 2nd dental examination, of which they had no prior knowledge.

RESULTS

On the last day of exams, approximately 6 weeks after professional tooth cleaning, 20.9+/-18.3% of control students' sites but only 10.5+/-9.3% of exam students' sites were found to be free of any plaque (p=0.022). Differences were most obvious at oral, as compared to vestibular, sites. Exam students reported a reduction in thoroughness (p=0.019) but not of frequency of oral hygiene behavior.

CONCLUSION

The study strongly supports the assumption that psychosocial stress may induce neglect of oral hygiene and increase of plaque accumulation.

Neutrophils die in the gingival crevice, periodontal pocket, and oral cavity by necrosis and not apoptosis

BACKGROUND

Neutrophils play important roles in the homeostasis of periodontal tissues. However, remarkably little is known about how these cells live and die in the gingival crevice and periodontal pocket. We have examined whether subgingival neutrophils die by necrosis or apoptosis and have begun to study the mechanisms controlling the functional lifespan of these cells.

METHODS

Neutrophils collected from clinically healthy gingival crevices, periodontal pockets, and the oral cavity (saliva) were examined with Hoechst dye 33342, propidium iodide/eithidium bromide, and FITC-annexin V to identify live, dead, and apoptotic cells. Blood neutrophils were cultured for 17 to 20 hours in the presence or absence of gingival crevice washings (GC-w) to study the effect of GC-w on neutrophil apoptosis. In addition, endotoxin was removed from GC-w by affinity resin to investigate the contribution of LPS to the inhibitory effect of GC-w on blood neutrophils.

RESULTS

The percentage of dead neutrophils in all subgingival sites and in all oral samples far exceeded the percentage of apoptotic neutrophils. In all 3 locations, approximately 30% of neutrophils were dead, whereas less than 1% of neutrophils were apoptotic. We conclude that the majority of neutrophils which lose their viability within gingival crevices, periodontal pockets and the oral cavity die by necrosis and not by apoptosis. Washings obtained from clinically healthy gingival crevices (GC-w) variably, but significantly, delayed apoptosis of peripheral blood neutrophils (mean suppression 45.7% +/- SD 22.3). Removal of endotoxin from GC-w significantly reduced this inhibitory effect.

CONCLUSIONS

Our findings provide insights into the mechanisms of neutrophil death and the control of the functional lifespan of neutrophils in gingival crevices and periodontal pockets and therefore into the pathogenesis of periodontal diseases.

Genetic polymorphisms of the IL-1alpha and IL-1beta genes in African-American LJP patients and an African-American control population

BACKGROUND

A functional polymorphism of the interleukin-1 beta (IL-1beta) gene has been proposed to be a risk factor for periodontitis. In adult forms of periodontitis, non-smokers of northern European heritage carrying the "2" allele of the IL-1alpha-889 and the IL-1beta +3953 RFLPs in either the heterozygous or the homozygous state at both loci were observed to have a greater risk for developing severe periodontitis. Studies of early-onset periodontitis (EOP) found that allele "1" of both IL-1alpha-889 and IL-1beta +3953 was transmitted more frequently with the EOP phenotype. The purpose of the present study was to determine the prevalence of the IL-1alpha and IL-1beta genotype polymorphisms in an African-American (AA) control population and in 37 African-Americans with localized juvenile periodontitis (LJP).

METHODS

The IL-1alpha +4845 and IL-1beta +3953 loci were genotyped by PCR amplification, followed by restriction enzyme digestion and gel electrophoresis. The IL-1alpha +4845 locus, in linkage disequilibrium (>99%) with IL-1alpha-889, was genotyped because it is technically easier. Data were analyzed using r x c contingency tables.

RESULTS

The IL-1beta +3953 allele "1" was carried by >99% of the AA control population and by 100% of the AA LJP group, with most individuals being homozygous 1,1. The prevalence of the composite genotype with at least one allele "2" at each of the IL-1beta +3953 and IL-1alpha +4845 loci was 14% (AA control group) and 8% (AA LJP group).

CONCLUSIONS

Given the high frequency of the IL-1beta allele "1" in the African-American population, it would appear that knowledge of this +3953 polymorphism would provide little diagnostic or predictive information for LJP.

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.