Loss of alveolar bone density in postmenopausal, osteopenic women is associated with circulating levels of gelatinases.

OBJECTIVE: To determine whether circulating levels of two matrix metalloproteinases, MMP-2 and MMP-9, are associated with loss of alveolar bone density (ABD) or height (ABH), or with progression of periodontitis (relative clinical attachment level [RCAL]), among postmenopausal women with local and systemic bone loss. BACKGROUND: This study was planned as part of a 2-year randomized, double-blind, placebo-controlled, clinical trial examining efficacy/safety of subantimicrobial dose doxycycline (20 mg bid) in postmenopausal osteopenic women. This study examines whether serum levels of gelatinases are associated with local changes in the periodontium. METHODS: A sample of 113 women received periodontal maintenance for moderate to advanced chronic periodontitis and consented to analysis of stored serum biomarkers. Posterior vertical bitewings were taken, and serum collected, at baseline, one, and 2 years. ABD was determined by computer-assisted densitometric image analysis (CADIA), ABH by the Hausmann et al (1992, J Periodontol 63, 657) method, and RCAL by Florida Probe (every 6 months). MMPs were measured densitometrically on gelatin zymograms using denatured type I collagen as substrate and purified MMP-2 (72 kDa) and MMP-9 (92 kDa) as standards. Evidence of worsening in the periodontium at a tooth site was defined as a change from baseline of, for ABD, at least 14 densitometric units (for subcrestal locations) or 17 units (for crestal locations); of at least 0.4 mm for ABH; and of at least 1.5 mm for RCAL. Logistic regression models, while accounting for clustering, compared the odds of worsening in ABD, ABH, or RCAL, after 2 years of observation, between groups defined by baseline and concurrent levels of serum gelatinases. RESULTS: Changes in ABH and RCAL were not associated with circulating levels of MMP-2 or MMP-9. However, elevated odds of ABD loss over 24 months were associated, among smokers, with both baseline and concurrent levels of MMP-9 in the middle and highest tertile, and with concurrent levels of MMP-2 in the middle (but not the highest) tertile. Elevated odds of ABD loss were also associated, among women within 5 years of menopause, with baseline levels of MMP-2 in the highest tertile. CONCLUSION: Among postmenopausal osteopenic women, loss of ABD was associated, in smokers, with elevated circulating levels of MMP-9 and MMP-2. In those within 5 years of menopause, ABD loss was associated with elevated circulating levels of MMP-2.

The subgingival microbiome in patients with established rheumatoid arthritis.

OBJECTIVES: To profile and compare the subgingival microbiome of RA patients with OA controls. METHODS: RA (n = 260) and OA (n = 296) patients underwent full-mouth examination and subgingival samples were collected. Bacterial DNA was profiled using 16 S rRNA Illumina sequencing. Following data filtering and normalization, hierarchical clustering analysis was used to group samples. Multivariable regression was used to examine associations of patient factors with membership in the two largest clusters. Differential abundance between RA and OA was examined using voom method and linear modelling with empirical Bayes moderation (Linear Models for Microarray Analysis, limma), accounting for the effects of periodontitis, race, marital status and smoking. RESULTS: Alpha diversity indices were similar in RA and OA after accounting for periodontitis. After filtering, 286 taxa were available for analysis. Samples grouped into one of seven clusters with membership sizes of 324, 223, 3, 2, 2, 1 and 1 patients, respectively. RA-OA status was not associated with cluster membership. Factors associated with cluster 1 (vs 2) membership included periodontitis, smoking, marital status and Caucasian race. Accounting for periodontitis, 10 taxa (3.5% of those examined) were in lower abundance in RA than OA. There were no associations between lower abundance taxa or other select taxa examined with RA autoantibody concentrations. CONCLUSION: Leveraging data from a large case-control study and accounting for multiple factors known to influence oral health status, results from this study failed to identify a subgingival microbial fingerprint that could reliably discriminate RA from OA patients.

Autoimmunity of the lung and oral mucosa in a multisystem inflammatory disease: The spark that lights the fire in rheumatoid arthritis?

There is a growing body of evidence to suggest that autoimmunity in patients with rheumatoid arthritis (RA) is initiated outside the joint. This is supported by the observation that circulating autoantibodies, including both rheumatoid factor and anti-citrullinated protein antibody, can be detected in many subjects years before the development of initial joint symptoms leading to an RA diagnosis. Of the potential extra-articular sites implicated in disease initiation, mucosal tissues have garnered increasing attention. Several lines of investigation have separately implicated mucosal tissues from varying anatomic locations as possible initiating sites for RA, including those from the lung and oral cavity. In this review we summarize recent reports incriminating these mucosal tissues as the initial site of autoantibody generation and inflammation in patients with RA.

Identification of an immunodominant peptide from citrullinated tenascin-C as a major target for autoantibodies in rheumatoid arthritis.

OBJECTIVES: We investigated whether citrullinated tenascin-C (cTNC), an extracellular matrix protein expressed at high levels in the joints of patients with rheumatoid arthritis (RA), is a target for the autoantibodies in RA. METHODS: Citrullinated sites were mapped by mass spectrometry in the fibrinogen-like globe (FBG) domain of tenascin-C treated with peptidylarginine deiminases (PAD) 2 and 4. Antibodies to cyclic peptides containing citrullinated sites were screened in sera from patients with RA by ELISA. Potential cross-reactivity with well-established anticitrullinated protein antibody (ACPA) epitopes was tested by inhibition assays. The autoantibody response to one immunodominant cTNC peptide was then analysed in 101 pre-RA sera (median 7 years before onset) and two large independent RA cohorts. RESULTS: Nine arginine residues within FBG were citrullinated by PAD2 and PAD4. Two immunodominant peptides cTNC1 (VFLRRKNG-cit-ENFYQNW) and cTNC5 (EHSIQFAEMKL-cit-PSNF-cit-NLEG-cit-cit-KR) were identified. Antibodies to both showed limited cross-reactivity with ACPA epitopes from α-enolase, vimentin and fibrinogen, and no reactivity with citrullinated fibrinogen peptides sharing sequence homology with FBG. cTNC5 antibodies were detected in 18% of pre-RA sera, and in 47% of 1985 Swedish patients with RA and 51% of 287 North American patients with RA. The specificity was 98% compared with 160 healthy controls and 330 patients with osteoarthritis. CONCLUSIONS: There are multiple citrullination sites in the FBG domain of tenascin-C. Among these, one epitope is recognised by autoantibodies that are detected years before disease onset, and which may serve as a useful biomarker to identify ACPA-positive patients with high sensitivity and specificity in established disease.

Associations between periodontitis and serum anti-malondialdehyde-acetaldehyde antibody concentrations in rheumatoid arthritis: A case-control study.

BACKGROUND: Malondialdehyde-acetaldehyde (MAA) adducts lead to generation of anti-MAA autoantibodies and have been independently identified in inflamed periodontal and rheumatoid arthritis (RA) tissues. This study evaluates serum samples from RA cases and osteoarthritis (OA) controls to quantify associations between periodontal clinical measures, alveolar bone loss (ABL), and anti-Porphyromonas gingivalis, anti-Prevotella intermedia, and anti-Fusobacterium nucleatum antibody concentrations with anti-MAA antibody concentrations. METHODS: Participants (n = 284 RA cases, n = 330 OA controls) underwent periodontal clinical assessments and ABL measurements. Serum immunoglobulin (Ig) A, IgG, and IgM anti-MAA and serum IgG antibacterial antibody concentrations were quantified by enzyme-linked immunosorbent assay (ELISA). Analyses utilized simple linear regression and multivariable adjusted models. RESULTS: No significant associations of periodontal clinical measures with serum anti-MAA were found. Moderate (p = 0.038 and p = 0.036, respectively) and high ABL (p = 0.012 and p = 0.014, respectively) in RA cases (but not in OA) were positively associated with IgG and IgM anti-MAA. Anti-P. gingivalis and anti-P. intermedia antibody concentrations were positively associated with IgA (p = 0.001 for both), IgG (p = 0.007 and p = 0.034, respectively), and IgM anti-MAA antibody concentrations (p < 0.001 and p = 0.020, respectively), while anti-F. nucleatum was positively associated with IgG anti-MAA (p = 0.042), findings that were similar across groups. CONCLUSIONS: A positive association was demonstrated between ABL and serum IgG and IgM anti-MAA antibody concentrations that was unique to RA and not observed in OA. Serum anti-P. gingivalis, anti-P. intermedia, and anti-F. nucleatum antibody concentrations displayed significant associations with anti-MAA antibody in both groups. These findings suggest MAA may play a role in the interrelationship between the periodontium and RA.

Subantimicrobial-dose doxycycline treatment increases serum cholesterol efflux capacity from macrophages.

OBJECTIVE: Subantimicrobial-dose doxycycline (SDD) treatment has been reported to reduce the severity of chronic inflammation and to increase serum high-density lipoprotein cholesterol. In a double-blind, placebo-controlled clinical trial, we determined whether SDD affects the ability of serum to facilitate cholesterol removal from macrophages. METHODS: Forty-five postmenopausal osteopenic women with periodontitis were randomly assigned to take placebo (n = 26) or doxycycline hyclate (20 mg, n = 19) tablets twice daily for 2 years. Serum samples were collected at baseline, 1-, and 2-year appointments. The cholesterol efflux capacity of serum from cultured human macrophages (THP-1) was measured. RESULTS: SDD subjects demonstrated a significant increase in serum-mediated cholesterol efflux from macrophages at both time points compared to baseline (p < 0.04 for each). Mean cholesterol efflux levels over the first year of follow-up were 3.0 percentage points (unit change) higher among SDD subjects compared to placebo subjects (p = 0.010), while there was no significant difference in 2-year changes. There were no significant differences in the changes of apolipoprotein A-I, apolipoprotein A-II, or serum amyloid A levels between the groups. CONCLUSIONS: Our results suggest that SDD treatment may reduce the risk of cardiovascular disease in this patient group by increasing the cholesterol efflux capacity of serum.

Porphyromonas gingivalis and disease-related autoantibodies in individuals at increased risk of rheumatoid arthritis.

OBJECTIVE: To examine the relationship of Porphyromonas gingivalis to the presence of autoantibodies in individuals at risk of rheumatoid arthritis (RA). METHODS: Study participants included the following: 1) a cohort enriched in subjects with HLA-DR4 and 2) subjects at risk of RA by virtue of having a first-degree relative with RA. None of the study subjects satisfied the American College of Rheumatology 1987 classification criteria for RA. Autoantibodies measured included anti-citrullinated protein antibody (ACPA; by second-generation anti-cyclic citrullinated peptide antibody enzyme-linked immunosorbent assay [ELISA]) and rheumatoid factor (RF; by nephelometry or ELISA for IgA, IgM, or IgG isotype). Individuals were considered autoantibody positive (n = 113) if they had ≥1 RA-related autoantibody; individuals were further categorized as high risk (n = 38) if they had ACPA or positive findings ≥2 assays for RF. Autoantibody-negative individuals (n = 171) served as a comparator group. Antibody to P gingivalis, P intermedia, and F nucleatum were measured. Associations of bacterial antibodies with group status were examined using logistic regression. RESULTS: Anti-P gingivalis concentrations were higher in high-risk (P = 0.011) and autoantibody positive group (P = 0.010) than in the autoantibody negative group. There were no group differences in anti-P intermedia or anti-F nucleatum concentrations. After multivariable adjustment, anti-P gingivalis concentrations (but not anti-P intermedia or anti-F nucleatum) were significantly associated with autoantibody-positive and high-risk status (P < 0.05). CONCLUSION: Immunity to P gingivalis, but not P intermedia or F nucleatum, is significantly associated with the presence of RA-related autoantibodies in individuals at risk of RA. These results support the hypothesis that infection with P gingivalis may play a central role in the early loss of tolerance to self antigens that occurs in the pathogenesis of RA.

Assessing the Agreement of Light Microscopic Evaluation of Oral Lichen Planus Lesions With Associated Direct Immunofluorescence Evaluation.

Aim/objective: Assess agreement between light microscopy and direct immunofluorescence (DIF) for histopathologic evaluation of oral lichen planus (OLP). Methods: Records evaluated included 60 OLP, 16 lichenoid mucositis (LM), and 56 non-OLP/non-LM cases. Cases had both light microscopic and DIF evaluations. Histopathologic parameters of OLP included: (1) hydropic degeneration of the basal cell layer, (2) band-like lymphocytic infiltrate immediately subjacent to the epithelium, and (3) presence of Civatte bodies. Two calibrated examiners independently assessed light microscopic features. Examiners reviewed cases with discordant diagnoses to determine a consensus diagnosis. Intra-rater reliability (IRR), sensitivity, specificity, positive, and negative predictive values (PPV and NPV) were determined. Results: Of 132 patients, 72.7% were female, average age 61.9 (SD = 13.8). Most common sites were gingiva (37.9%), buccal mucosa (37.1%), and tongue (7.6%). IRR was 0.74 (95% CI: 0.40, 1.00) for the consensus diagnosis and 0.73 (95% CI: 0.39, 1.00) and 0.34 (95% CI: -0.03, 0.72) for the 2 examiners. Comparing consensus and definitive diagnoses: sensitivity of light microscopy: 0.32 (95% CI: 0.20, 0.45); specificity: 0.88 (95% CI: 0.78, 0.94); PPV: 0.68 (95% CI: 0.48, 0.84), and NPV: 0.61 (95% CI: 0.51, 0.70). Conclusion: Light microscopy alone is not a viable alternative to adjunctive DIF for diagnosis of OLP lesions.

Serum antibodies to periodontal pathogens prior to rheumatoid arthritis diagnosis: A case-control study.

OBJECTIVES: 1) To quantify the association between anti-Porphyromonas gingivalis serum antibody concentrations and the risk of developing rheumatoid arthritis (RA), and 2) to quantify the associations among RA cases between anti-P. gingivalis serum antibody concentrations and RA-specific autoantibodies. Additional anti-bacterial antibodies evaluated included anti-Fusobacterium nucleatum and anti-Prevotella intermedia. METHODS: Serum samples were acquired pre- and post- RA diagnosis from the U.S. Department of Defense Serum Repository (n = 214 cases, 210 matched controls). Using separate mixed-models, the timing of elevations of anti-P. gingivalis, anti-P. intermedia, and anti-F. nucleatum antibody concentrations relative to RA diagnosis were compared in RA cases versus controls. Associations were determined between serum anti-CCP2, ACPA fine specificities (vimentin, histone, and alpha-enolase), and IgA, IgG, and IgM RF in pre-RA diagnosis samples and anti-bacterial antibodies using mixed-effects linear regression models. RESULTS: No compelling evidence of case-control divergence in serum anti-P. gingivalis, anti-F. nucleatum, and anti-P. intermedia was observed. Among RA cases, including all pre-diagnosis serum samples, anti-P. intermedia was significantly positively associated with anti-CCP2, ACPA fine specificities targeting vimentin, histone, alpha-enolase, and IgA RF (p<0.001), IgG RF (p = 0.049), and IgM RF (p = 0.004), while anti-P. gingivalis and anti-F. nucleatum were not. CONCLUSIONS: No longitudinal elevations of anti-bacterial serum antibody concentrations were observed in RA patients prior to RA diagnosis compared to controls. However, anti-P. intermedia displayed significant associations with RA autoantibody concentrations prior to RA diagnosis, suggesting a potential role of this organism in progression towards clinically-detectable RA.

Using tetracyclines to treat osteoporotic/osteopenic bone loss: from the basic science laboratory to the clinic.

Periodontitis (progressive inflammatory disease characterized by alveolar bone loss, a major cause of tooth loss worldwide) is associated with both systemic osteoporosis and its milder form, osteopenia. Tetracyclines, by virtue of their non-antimicrobial pro-anabolic and anti-catabolic properties, are excellent candidate pharmaceuticals to simultaneously treat these local and systemic disorders. This paper reviews the foundational basic science and translational research which lead to a pivotal multicenter randomized clinical trial in postmenopausal women with both periodontitis and systemic (skeletal) osteopenia. This trial was designed primarily to examine whether subantimicrobial dose doxycycline (SDD) could reduce progressive alveolar (oral) bone loss associated with periodontitis and, secondarily, whether SDD could reduce systemic bone loss in the same subjects. This paper describes the efficacy and safety findings from this clinical trial and also outlines future directions using this promising and novel approach to manage both oral and systemic bone loss.

Performance of a commercially available multiplex platform in the assessment of circulating cytokines and chemokines in patients with rheumatoid arthritis and osteoarthritis.

BACKGROUND/OBJECTIVE: Cytokines and chemokines (cytokines) are central to rheumatoid arthritis (RA) pathogenesis, with increasing use of multiplex immunoassays in clinical/research settings. Rheumatoid factor (RF) may interfere with assay outcomes by nonspecifically binding detection analytes. We evaluated the performance of a commercially available multiplex platform, including assessment of the impact of RF depletion. METHODS: Forty-five cytokines were tested using Meso Scale Discovery V-PLEX™ and samples from 40 RA and 40 osteoarthritis (OA) patients. Select samples were depleted of RF using a commercial binder. Performance was assessed using intra-assay coefficients of variation (CV), intraclass correlation coefficients (ICC), percent change following RF depletion, and disease discrimination. Values above or below quantification thresholds were imputed. RESULTS: Of the 45 cytokines analyzed, 31 yielded CVs <10%; none demonstrated CVs >30%. ICCs universally exceeded 0.85 with the exception of eight analytes. RF depletion altered cytokine values by <15% for 40 analytes with larger changes (>30%) only seen for one analyte. Twenty-three cytokines differed significantly based on measurement in plasma vs. serum. Three analytes were higher in the serum of RA vs. OA (IL-10, IP-10, TNFα), and none were significantly greater in OA vs. RA. Seventeen analytes required imputation for >50% of the samples tested, primarily related to concentrations below the lower limit of quantification threshold. CONCLUSION: The results from this commercially available multiplex assay were generally highly reproducible and interference induced by RF only meaningfully impacted the quantification of five of the analytes examined.

Effects of enamel matrix derivative on clinical and inflammatory outcomes in periodontal maintenance patients: Randomized controlled clinical trial.

BACKGROUND: Efficient methods to treat persistent pockets during periodontal maintenance therapy (PMT) require further investigation. The hypothesis of this randomized controlled clinical trial was that local application of enamel matrix derivative (EMD) added to papilla reflection/root preparation (PR/RP) could enhance clinical and inflammatory outcomes, primarily clinical attachment level (CAL). METHODS: Fifty PMT patients with generalized stage III-IV, grade B periodontitis presenting with a 6- to 9-mm interproximal PD were randomly allocated to (PR/RP+EMD; n = 24) and control (PR/RP+saline; n = 26) therapies by sex and smoking status. Roots were treated with reflection of interproximal papillae, root planing assisted with endoscope evaluation, and acid etching, followed by EMD or saline application. Probing depth (PD), CAL, plaque index (PI), and interproximal bone height were evaluated at baseline and 12-months post-therapy. Gingival crevicular fluid, bleeding on probing (BOP), and interleukin-1ß were tested (ELISA) at baseline, 2 weeks, and 6 and 12 months. Groups were compared over time and between groups with Wilcoxon Rank Sum and t-tests. RESULTS: Both PR/RP+ EMD and PR/RP+S resulted in significant improvements in clinical outcomes (PD and CAL, BOP) from baseline to 12 months. No significant differences were found in clinical or inflammatory outcomes between the experimental and control groups. CONCLUSIONS: The addition of EMD to PR/RP does not significantly improve clinical or inflammatory outcomes compared with PR/RP alone during periodontal maintenance therapy.

Antibody responses to Porphyromonas gingivalis (P. gingivalis) in subjects with rheumatoid arthritis and periodontitis.

UNLABELLED: Antibody titers to P. gingivalis are increased in patients with rheumatoid arthritis and are associated with disease-specific autoimmunity. BACKGROUND: Periodontitis (PD) has been implicated as a risk factor for rheumatoid arthritis (RA). We sought to characterize antibody titers to P. gingivalis (a pathogen in PD) in subjects with RA, PD, and in healthy controls and to examine their relationship with disease autoantibodies. METHODS: P. gingivalis antibody was measured in subjects with RA (n=78), PD (n=39), and in controls (n=40). Group frequencies of bacterial titer elevations were compared using the Chi-square test and antibody titers were compared using non-parametric tests. Correlations of P. gingivalis titer with C-reactive protein (CRP), antibody to cyclic citrullinated peptide (anti-CCP), and rheumatoid factor (RF) were examined in those with RA while CRP and autoantibody concentrations were compared based on seropositivity to P. gingivalis. RESULTS: Antibody titers to P. gingivalis were highest in PD, lowest in controls, and intermediate in RA (p=0.0003). Elevations in P. gingivalis (titer> or =800) were more common in RA and PD (67% and 77%, respectively) than in controls (40%) (p=0.002). In RA, there were significant correlations with P. gingivalis titer with CRP, anti-CCP-IgM, and -IgG-2. CRP (p=0.006), anti-CCP-IgM (p=0.01) and -IgG2 (p=0.04) concentrations were higher in RA cases with P. gingivalis titers > or =800 compared to cases with titers <800. CONCLUSION: Antibodies to P. gingivalis are more common in RA subjects than controls, although lower than that in PD. Associations of P. gingivalis titers with RA-related autoantibody and CRP concentrations suggests that infection with this organism plays a role in disease risk and progression in RA.

Subantimicrobial-dose doxycycline modulates gingival crevicular fluid biomarkers of periodontitis in postmenopausal osteopenic women.

BACKGROUND: We recently demonstrated that a 2-year subantimicrobial-dose doxycycline (SDD) regimen (double-masked, placebo-controlled clinical trial) in postmenopausal (PM) women exhibiting mild systemic bone loss (osteopenia) and local bone loss (periodontitis) reduced the progression of periodontal attachment loss (intent-to-treat analysis) and the severity of gingival inflammation and alveolar bone loss (subgroups) without producing antibiotic side effects. We now describe SDD effects on biomarkers of collagen degradation and bone resorption in the gingival crevicular fluid (GCF) of the same vulnerable subjects. METHODS: GCF was collected from SDD- and placebo-treated PM subjects (n=64 each) at the baseline and 1- and 2-year appointments; the volume was determined; and the samples were analyzed for collagenase activity (using a synthetic peptide as substrate), relative levels of three genetically distinct collagenases (Western blot), a type-1 collagen breakdown product/bone resorption marker (a carboxyterminal telopeptide cross-link fragment of type I collagen [ICTP]; radioimmunoassay), and interleukin-1beta (enzyme-linked immunosorbent assay). Statistical analyses were performed using generalized estimating equations; primary analyses were intent-to-treat. RESULTS: Collagenase activity was significantly reduced by SDD treatment relative to placebo based on intent-to-treat (P=0.01). ICTP showed a similar pattern of change during SDD treatment, and GCF collagenase activity and ICTP were positively correlated at all time periods (P<0.001). Matrix metalloproteinase (MMP)-8 accounted for approximately 80% of total collagenase in GCF, with much less MMP-1 and -13, and SDD reduced the odds of elevated MMP-8 by 60% compared to placebo (P=0.006). CONCLUSION: These observations support the therapeutic potential of long-term SDD therapy to reduce periodontal collagen breakdown and alveolar bone resorption in PM women; effects on serum biomarkers of systemic bone loss in these subjects are being analyzed.

Malondialdehyde-acetaldehyde antibody concentrations in rheumatoid arthritis and other rheumatic conditions.

OBJECTIVE: To compare anti-malondialdehyde-acetaldehyde (MAA) antibody concentrations between rheumatoid arthritis (RA) patients and healthy and rheumatic disease controls. METHODS: Anti-MAA antibody (IgA, IgM, IgG) was measured using ELISA and banked serum from patients with RA (n = 284), osteoarthritis (OA, n = 330), spondyloarthropathy (SpA, n = 50), and systemic lupus erythematosus (SLE, n = 88) as well as healthy controls (n = 82). Anti-MAA antibody concentrations and the frequency of positivity were compared across groups. Multivariable linear regression analysis limited to RA and OA patients (due to sample size and data availability) was used to identify factors associated with anti-MAA antibody concentrations. RESULTS: Although RA patients demonstrated among the highest circulating concentrations across isotypes, only IgA anti-MAA antibody was significantly higher than all other groups (p ≤ 0.02). Proportions (7% to 74%) of OA and SLE (less so for SpA) samples were positive for anti-MAA antibody, limiting the discriminatory capacity of anti-MAA antibody in RA (positive in 18% to 80%). In analyses limited to those with RA or OA, factors associated with higher anti-MAA antibody concentrations included RA case status, younger age (IgM), male sex (IgG), African American race (IgA, IgG) and current smoking (IgA). C-reactive protein levels and comorbidities were not associated with anti-MAA antibody concentrations. CONCLUSION: With the possible exception of the IgA isotype, serum anti-MAA antibodies measured with currently available assays do not appear to adequately discriminate RA from other rheumatic conditions. With the identification of specific proteins that are MAA-modified in diseased tissues and requisite assay refinement, anti-MAA antibody holds potential promise as a biomarker in RA.

Subantimicrobial dose doxycycline effects on osteopenic bone loss: microbiologic results.

BACKGROUND: Based on microbiologic concerns, the safety of a 24-month regimen of subantimicrobial dose doxycycline (SDD; 20 mg twice a day) was evaluated in postmenopausal osteopenic women with periodontitis in a double-blind, placebo-controlled, randomized clinical trial. METHODS: Subgingival samples were collected from two sites (probing depth > or = 5 mm) in each of 128 subjects at baseline, with the same sites resampled at the conclusion of the 2-year period. The samples were enumerated on selective and non-selective media and on doxycycline (4 microg/ml) medium. Up to five different colonial morphologies were subcultured from the doxycycline medium, identified to species, and susceptibilities determined to doxycycline and five other antibiotics. Data were analyzed for microbial differences in total colony forming units (CFU), periodontal and opportunistic pathogens, and changes in species and in susceptibilities of isolates recovered on doxycycline medium. RESULTS: There was no significant evidence that changes in total anaerobic counts over the treatment period (P = 0.96) differed between treatment groups. Likewise, periodontal pathogens, opportunistic pathogens, or normal flora did not differ descriptively between groups. Although there was a significant increase (P <0.001) in the total CFU recovered from the 4 microg/ml doxycycline plates at 24 months for SDD versus placebo, the percentage that was clinically resistant to doxycycline (minimal inhibitory concentration [MIC] > or = 16 microg/ml) decreased over the 24-month period in both groups and did not differ between the treatment groups (SDD: 79% to 76%; placebo: 83% to 70%; P = 0.2). There were no significant differences (P >0.28 for each) in the change in cross-resistance between the groups for doxycycline and the other five antibiotics. CONCLUSIONS: No antimicrobial effect on the subgingival flora was detected following treatment with SDD for 24 months, relative to baseline or to placebo. The increase in initial resistance (at 4 microg/ml) did not translate into a significant increase in the percent resistant to doxycycline (MIC > or = 16 microg/ml) for patients in the SDD group.

A Comparison of Efficiency and Material Wear of Diamond-Plated versus Ceramic Sharpening Stones.

Purpose: The purpose of this study was to compare sharpening efficiency and metal (carbon steel) removal from scalers using two types of synthetic sharpening stones: ceramic and diamond-plated. Previous research used scanning electron microscopy alone to measure instrument sharpness. Additionally, no research has been reported on the use of diamond-plated sharpening stones.Methods: Fifteen threaded, double-ended H6/H7 scalers were randomly divided into three groups of ten: control, ceramic stone, and diamond-plated stone. All cutting edges were dulled by scaling the surfaces of extracted molars. The cutting edges were then sharpened by a blinded examiner with the assigned stone until optimal sharpness was achieved using a test stick between sharpening strokes. The number of strokes needed to reach sharpness for each cutting edge was recorded. Four hundred sharpening strokes were then applied on each end using the assigned stone. The scaler ends were weighed before and after sharpening to determine amount of material loss in milligrams. Statistical analysis was performed using ANOVA followed by a Tukey-Kramer post-hoc test.Results: The diamond-plated sharpening stone removed significantly more metal (7.62 mg +/-0.38) than the ceramic stone (0.69 mg +/-0.06) (p<0.001), while there was no significant difference between the ceramic sharpening stone and the control. There was no significant difference between diamond-plated and ceramic stones in the number of strokes needed to sharpen scalers.Conclusion: While a similar number of strokes was needed to sharpen scalers with the diamond-plated or ceramic stone, the diamond-plated stone removed nearly 7 mg more metal than the ceramic stone using a standardized number of sharpening strokes, suggesting greater scaler longevity when using a ceramic sharpening stone.

Subgingival Microbiome Colonization and Cytokine Production during Early Dental Implant Healing.

Little is known about longitudinal development of the peri-implant subgingival microbiome and cytokine production as a new sulcus forms after dental implant placement. Therefore, the purpose of this observational study was to evaluate simultaneous longitudinal changes in the oral microbiome and cytokine production in the developing peri-implant sulcus compared to control natural teeth. Four and 12 weeks after implant placement and abutment connection, a dental implant and a natural tooth were sampled in 25 patients for subgingival plaque and gingival crevicular fluid (GCF [around teeth] and peri-implant crevicular fluid [PICF] around implants). DNA from plaque samples was extracted and sequenced using Illumina-based 16S rRNA sequencing. GCF and PICF samples were analyzed using a customized Milliplex human cytokine and chemokine magnetic bead panel. Beta diversity analysis revealed that natural teeth and implants had similar subgingival microbiomes, while teeth had greater alpha diversity than implants. At the genus level, however, few differences were noted between teeth and dental implants over 12 weeks. Specifically, Actinomyces and Selenomonas were significantly elevated around teeth versus dental implants at both 4 weeks and 12 weeks, while Corynebacterium and Campylobacter were significantly elevated only at 4 weeks around teeth. The only difference between PICF and GCF biomarkers was significantly elevated granulocyte-macrophage colony-stimulating factor levels around teeth versus dental implants at the 4-week visit. The subgingival microbiome and cytokine production were similar between teeth and implants during early healing, suggesting that these profiles are driven by the patient following dental implant placement and are not determined by anatomical niche. IMPORTANCE Dental implants are a common treatment option offered to patients for tooth replacement. However, little is known regarding initial colonization of the subgingival microbiome and simultaneous longitudinal cytokine production in humans during the early healing phase following implant placement. We report findings from an in vivo study that assessed initial colonization of the subgingival microbiome and concomitant early cytokine production in a newly formed anatomical space, namely, an implant sulcus. This approach may be useful in future interventional studies to influence dental implant success. Our data showed that the subgingival microbiome and cytokine profile were similar for control natural teeth and dental implants at both 4 and 12 weeks after implant placement. These data suggest that these profiles are driven by the patient and not by anatomical location (i.e., tooth versus dental implant).