Gingival tissue, an extrasynovial source of malondialdehyde-acetaldehyde adducts, citrullinated and carbamylated proteins.

BACKGROUND AND OBJECTIVE: Postranslational modification of proteins can lead to the production of autoantibodies and loss of immune tolerance. This process has been hypothesised to be a critical factor in the pathogenesis of rheumatoid arthritis. The objective of this study was to demonstrate that inflamed human gingival tissue provides an extrasynovial source of malondialdehyde-acetaldehyde adducts, citrullinated and carbamylated proteins all of which are considered to be linked to the development of rheumatoid arthritis. Identification of such modified proteins in inflamed gingiva may explain, in part, how inflammation of the periodontal tissues may influence the development of rheumatoid arthritis. MATERIAL AND METHODS: Gingival biopsies of healthy, mild and moderate periodontitis were triple stained with antibodies against malondialdehyde-acetaldehyde adducts, citrullinated and carbamylated proteins. RESULTS: Assessment of healthy gingival tissue revealed negligible staining for carbamylated, malondialdehyde-acetaldehyde (MAA), or citrullinated proteins. Mild periodontitis was positive for all three modifications. Furthermore, there was an increase in staining intensity for carbamylated, citrullinated and MAA-modified proteins in moderate periodontitis. Negative staining results were observed for the isotype controls. CONCLUSION: This study provides evidence for the presence of citrullinated, carbamylated and MAA adduct modified proteins in inflamed periodontal tissues. The potential for these proteins to play a role in autoimmunity in a multi-system inflammatory syndromic disease model now needs to be determined.

TLR4 Asp299Gly polymorphism may be protective against chronic periodontitis.

BACKGROUND AND OBJECTIVE: Periodontitis results from interplay between genetic and environmental factors. Single nucleotide polymorphisms (SNPs) in the coding region of the toll-like receptor 4 gene (TLR4) may be associated with periodontitis, although previous studies have been inconclusive. Moreover, the interaction between environmental factors, such as cigarette smoking (a major risk factor for periodontitis), and Porphyromonas gingivalis (a major periodontal pathogen) with the TLR4 coding region Asp299Gly SNP (rs4986790; a SNP associated with lipopolysaccharide-mediated inflammatory responses in periodontitis), have been largely ignored in previous reports. Therefore, the objective of this study was to examine the association between TLR4 Asp299Gly (rs4986790) with alveolar bone height loss (ABHL) and periodontitis, accounting for interactions between this SNP with smoking and P. gingivalis prevalence. The CD14/-260 SNP (rs2569190) served as a control, as a recent meta-analysis suggested no relationship between this SNP and periodontitis. MATERIAL AND METHODS: This multicenter study included 617 participants who had rheumatoid arthritis or osteoarthritis. This report presents a secondary outcome from the primary case-control study examining the relationship of periodontitis with established rheumatoid arthritis. The Centers for Disease Control/American Academy of Periodontology case definitions of periodontitis were used for this analysis. Participants received a full-mouth clinical periodontal examination and panoramic radiograph. Percentage ABHL was measured on posterior teeth. The TLR4 Asp299Gly and CD14/-260 SNPs were selected a priori and genotypes were determined using the ImmunoChip array (Illumina(®) ). Minor allele frequencies and associations with periodontitis and ABHL did not differ according to rheumatoid arthritis vs. osteoarthritis status; therefore, data from these two groups were pooled. The presence of P. gingivalis was detected in subgingival plaque by PCR. Multivariate ordinal logistic regression examined associations between the SNPs and periodontitis or ABHL. SNP interactions with smoking and P. gingivalis were analyzed. RESULTS: A significant, negative interaction was observed between the TLR4 SNP and the presence of P. gingivalis (p = 0.045) with respect to periodontitis. The TLR4 minor variant was also associated with less ABHL: 16.8% of individuals with low ABHL, 9.0% with moderate ABHL and 11.2% with high ABHL had the minor allele [p = 0.029; odds ratio = 0.58 (95% confidence interval: 0.36-0.95)]. The interaction between the TLR4 SNP and smoking was not significant with respect to periodontitis or ABHL. The CD14 SNP was not associated with periodontitis or ABHL. CONCLUSION: The TLR4 Asp299Gly SNP significantly interacted with P. gingivalis in conferring a decreased risk of periodontitis and may be protective against ABHL, a feature of periodontitis. Agents blocking TLR4 signaling, a strategy currently under investigation for the treatment of other inflammatory conditions, may warrant investigation in the context of periodontitis related to the presence of P. gingivalis.

Interactions of microorganisms with polymer nanocomposite surfaces containing oxidized carbon nanotubes.

In many environmental scenarios, the fate and impact of polymer nanocomposites (PNCs) that contain carbon nanotubes (CNT/PNCs) will be influenced by their interactions with microorganisms, with implications for antimicrobial properties and the long-term persistence of PNCs. Using oxidized single-wall (O-SWCNTs) and multi-wall CNTs (O-MWCNTs), we explored the influence that CNT loading (mass fraction≤0.1%-10%) and type have on the initial interactions of Pseudomonas aeruginosa with O-CNT/poly(vinyl alcohol) (PVOH) nanocomposites containing well-dispersed O-CNTs. LIVE/DEAD staining revealed that, despite oxidation, the inclusion of O-SWCNTs or O-MWCNTs caused PNC surfaces to exhibit antimicrobial properties. The fraction of living cells deposited on both O-SWCNT and O-MWCNT/PNC surfaces decreased exponentially with increasing CNT loading, with O-SWCNTs being approximately three times more cytotoxic on a % w/w basis. Although not every contact event between attached microorganisms and CNTs led to cell death, the cytotoxicity of the CNT/PNC surfaces scaled with the total contact area that existed between the microorganisms and CNTs. However, because the antimicrobial properties of CNT/PNC surfaces require direct CNT-microbe contact, dead cells were able to shield living cells from the cytotoxic effects of CNTs, allowing biofilm formation to occur on CNT/PNCs exposed to Pseudomonas aeruginosa for longer time periods.

Modeling the growth and death kinetics of Salmonella in poultry litter as a function of pH and water activity.

Contaminated poultry litter, serving as a reservoir for Salmonella, can be linked to both food safety concerns when contaminated birds enter processing plants and environmental concerns when used as a fertilizer. Predictive modeling allows for the estimation of microbial growth or inactivation as a function of controlling environmental growth factors. A study was conducted to observe the combined effects of pH and water activity (A(w)) at a constant temperature on Salmonella populations in used turkey litter to predict microbial response over time. Litter, first pH-adjusted and then inoculated with a 3-strain Salmonella serovar cocktail to an initial concentration of approximately 10(7) cfu/g, was placed into individual sealed plastic containers with saturated salt solutions for controlling A(w). A balanced design including 3 A(w) values (0.84, 0.91, 0.96), 3 pH values (4, 7, 9), and a constant temperature of 30 degrees C was used, with litter samples periodically removed and analyzed for Salmonella populations, pH, and A(w). At each combination of environmental factors, the Churchill or exponential inactivation mathematical models were used to describe the growth and death of Salmonella over time. Salmonella populations exhibited growth (approximately 2 log) with little decline up to 42 d in litter environments of pH 7 and 9 and a A(w) of 0.96. As litter A(w) and pH levels were reduced, populations declined, with the most drastic reductions (approximately 5 log in 9 h) occurring in low-pH (4) and low-A(w) (0.84) environments. Generalized models for bacterial growth and death under grouped pH environments were successfully developed to predict Salmonella behavior in litter over time. These findings suggest that the best management practices and litter treatments that lower litter A(w) to < or =0.84 and pH to < or =4 are effective in reducing Salmonella populations. The use of a single equation to predict the growth and decline of Salmonella populations as a function of pH and A(w) has potential application for use in the development of effective pathogen control strategies at the farm level.

Salmonella populations and prevalence in layer feces from commercial high-rise houses and characterization of the Salmonella isolates by serotyping, antibiotic resistance analysis, and pulsed field gel electrophoresis.

Salmonella species are recognized as a major cause of foodborne illnesses that are closely associated with the consumption of contaminated poultry and egg products. The objectives of this study were to evaluate the Salmonella populations and prevalence in layer feces during the laying cycle and molting of the hen and to characterize the layer fecal Salmonella isolates by serotyping, antibiotic resistance analysis, and pulsed field gel electrophoresis. Fecal samples were collected from a commercial layer complex consisting of 12 houses. Composite fecal samples across each row were collected as a function of bird age [18 wk (at placement), 25 to 28 wk (first peak of production cycle), 66 to 74 wk (molting), and 75 to 78 wk (second peak of production cycle)]. Bird ages and molting practice did not significantly affect (P > 0.05) Salmonella populations with an average of 1.25, 1.27, 1.20, and 1.14 log most probable number/g for the 18-, 25- to 28-, 66- to 74-, and 75- to 7-wk birds, respectively. However, the 18-wk birds had the highest prevalence of Salmonella (55.6%), followed by the 25- to 28-wk birds (41.7%), 75- to 78-wk birds (16.7%), and 66- to 74-wk birds (5.5%). Of the 45 Salmonella isolates characterized, the most predominant serovar was Salmonella Kentucky (62%). Thirty-five percent of the Salmonella isolates were resistant to at least 1 antibiotic. As expected, considerable genetic diversity was observed within and across the different serovars.

Filth Fly Activity Associated With Composted and Noncomposted Beef Cadavers and Laboratory Studies on Volatile Organic Compounds.

Commercial livestock facilities are faced with the challenge of managing large amounts of waste including manure and animal mortalities. One method of disposing of dead animals is composting. The cadavers are enveloped in carbon material that creates a barrier between the dead tissue and the surrounding environment. Dead tissue can release materials that not only contaminate the soil but also the groundwater and nearby surface water. Animal cadaver composting is designed to facilitate decomposition without the aid of carrion-feeding insects and reduce the presence of common pathogens associated with animal waste and dead tissue. The aim of this study was to evaluate insect activity associated with composted and exposed beef cadavers, specifically filth flies that can serve as mechanical vectors of important human pathogens such as E. coli 0157:H7. Greater numbers of all types of arthropods were trapped overall at the exposed animal site than the composted animal site. Most importantly, the number of filth flies was significantly lower at the composted site (P = 0.0009). Laboratory analysis of volatile organic compounds from composted and noncomposted rats indicated that known fly attractants such as dimethyl disulfide may be inhibited by the composting process. Implementing composting programs at livestock facilities could reduce the risk of flies spreading harmful pathogens to surrounding areas, including farms that grow fresh produce.

Salivary and serum procalcitonin and C-reactive protein as biomarkers of periodontitis in United States veterans with osteoarthritis or rheumatoid arthritis.

Serum procalcitonin (ProCT) is elevated in response to bacterial infections, whereas high sensitivity C-reactive protein (hsCRP) is a nonspecific inflammatory marker that is increased by excess adipose tissue. We examined the efficacy of ProCT and hsCRP as biomarkers of periodontitis in the saliva and serum of patients with arthritis, which is characterized by variable levels of systemic inflammation that potentially can confound the interpretation of inflammatory biomarkers. Blood and unstimulated whole saliva were collected from 33 patients with rheumatoid arthritis (RA) and 50 with osteoarthritis (OA). Periodontal status was assessed by full mouth examination and patients were categorized as having no/mild, moderate or severe periodontitis by standard parameters. Salivary and serum ProCT and hsCRP concentrations were compared. BMI, diabetes, anti-inflammatory medications and smoking status were ascertained from the patient records. Differences between OA and RA in proportionate numbers of patients were compared for race, gender, diabetes, adiposity and smoking status. Serum ProCT was significantly higher in arthritis patients with moderate to severe and severe periodontitis compared with no/mild periodontitis patients. There were no significant differences in salivary ProCT or salivary or serum hsCRP in RA patients related to periodontitis category. Most of the OA and RA patients were middle aged or older, 28.9% were diabetic, 78.3% were overweight or obese, and slightly more than half were either current or past smokers. The OA and RA groups differed by race, but not gender; blacks and males were predominant in both groups. The OA and RA groups did not differ in terms of controlled or uncontrolled diabetes, smoking status or BMI. The RA patients had been prescribed more anti-inflammatory medication than the OA patients. Our results demonstrate that circulating ProCT is a more discriminative biomarker for periodontitis than serum hsCRP in patients with underlying arthritis. Any elevation in salivary and serum hsCRP due to periodontitis apparently was overshadowed by differences among these patients in factors that influence CRP, such as the extent of inflammation between RA and OA, the extent of adipose tissue, the use of anti- inflammatory medications and smoking status. Although our study showed no differences in salivary ProCT related to severity of periodontitis, this biomarker also may be useful with further refinement.

Preservation of neuronal function during prolonged focal cerebral ischemia by ventriculocisternal perfusion with oxygenated fluorocarbon emulsion.

The left middle cerebral artery and both carotid arteries of 17 cats were occluded to evaluate the effects of oxygenated fluorocarbon emulsion on brain ischemia. Carotid and middle cerebral arteries were occluded concurrently for 2 hours, followed by occlusion of the middle cerebral artery only for another 24 hours. Six animals were treated with oxygenated fluorocarbon emulsion delivered by ventriculocisternal perfusion, 5 received ventriculocisternal perfusion with mock cerebrospinal fluid, and 6 were untreated. Perfusions were started 3 hours after the initial ischemic insult. Infarct size judged by tetrazolium staining and standard neuropathological stains was significantly smaller in the treated animals. The mechanism of protection is as yet unknown, but most likely reflects oxygen/nutrient diffusion into the ischemic middle cerebral artery zone from the ventricular fluorocarbon, or removal of harmful metabolites. The results imply that ventriculocisternal perfusion with fluorocarbon emulsion can preserve neuronal function during a major cerebral vessel occlusion. In the cat, therapy is effective if begun within 3 hours after ischemia starts.

Effect of smokeless tobacco extract on human gingival keratinocyte levels of prostaglandin E2 and interleukin-1.

Gingival recession and white mucosal lesions frequently occur at sites of smokeless tobacco (ST) placement. The etiology of these alterations is presumably related to the irritating effects of tobacco components. The purpose of this study was to examine the effect of an aqueous ST extract (STE) on gingival keratinocyte production of prostaglandin E2 (PGE2) and interleukin-1 (IL-1), mediators involved in periodontal destruction and keratinocyte proliferation. Keratinocyte cultures were established from healthy tissues discarded from 8 subjects undergoing crown lengthening procedures. Cells (passage 2-3) were seeded at 2.5 x 10(4) cells/well into 48 well tissue culture plates and maintained in serum-free media at 37 degrees C. On day 4 or 5, the wells were divided into 4 groups receiving either 10%, 5%, 2.5%, or 0% STE for time periods ranging from 30 to 240 minutes. PGE2 levels (pg/10(4) cells), as measured by enzyme immunoassay, were significantly (P < 0.05) increased in the 10% (215.66 +/- 34.58) and 5% STE (151.82 +/- 27.97) treated cultures compared to untreated cells (46.16 +/- 9.58). IL-1 alpha and IL-1 beta proteins were elevated (P < 0.05) in cell lysates (299.45 +/- 38.69 and 28.45 +/- 5.18, respectively) from 5% STE exposed cultures compared to control wells. At 10% STE, secreted IL-1 alpha was decreased (P < 0.05) relative to 2.5% STE. This may reflect a toxic effect, as 10% STE significantly (P < 0.05) depressed cell numbers and viability. Lower tobacco concentrations did not affect cell numbers or viability, but significantly (P < 0.05) increased PGE2 and IL-1 levels. Tobacco-induced synthesis of these mediators may play a role in the development of tobacco-related oral disease.

The association between estrogen status and alveolar bone density changes in postmenopausal women with a history of periodontitis.

While numerous studies have demonstrated a relationship between 17-beta-estradiol (E2) deficiencies and skeletal bone loss in postmenopausal females, the influence of E2 deficiency on alveolar bone resorption is poorly understood. The purpose of this study was to examine the association between the estrogen status of postmenopausal women and alveolar bone density changes in a 1-year longitudinal study. Twenty-four postmenopausal women, within 7 years of menopause, were divided into 2 groups, E2-sufficient (n = 10) and E2-deficient (n = 14). Venous blood samples were taken at baseline, 6 months, and 1 year for radioimmunoassay determination of serum E2 levels. At baseline and 1 year, 4 vertical bite-wing radiographs were taken for computer-assisted densitometric image analysis (CADIA). Areas of interest (AOIs) for CADIA were crestal and subcrestal regions of posterior interproximal alveolar bone. Serum E2 levels were significantly higher at all 3 time points in the E2-sufficient subjects (P < 0.002), repeated measures ANOVA). Overall, mean CADIA values (0.30 +/- 0.07 for the E2-sufficient women and -0.44 +/- 0.07 for the E2-deficient women) were statistically different between groups (P < 0.001, repeated measures ANOVA), indicating that the E2-sufficient women displayed a mean net gain in alveolar bone density and the E2-deficient women displayed a mean net loss in alveolar bone density. Furthermore, the E2-sufficient women exhibited a higher frequency of sites demonstrating a gain in alveolar bone density, while the E2-deficient women exhibited a higher frequency of sites demonstrating loss in alveolar bone density. These data suggest that estrogen status may influence alveolar bone density changes as demonstrated with CADIA.

Smokeless tobacco effects on monocyte secretion of PGE2 and IL-1 beta.

The use of smokeless tobacco (ST) products is associated with mucosal lesions, gingival recession, and attachment loss at the site of tobacco placement. Monocytes/macrophages are primary producers of PGE2 and IL-1 beta, inflammatory mediators which are thought to play a role in the destruction of the periodontium. The purpose of this study was to determine the effect of ST alone and in combination with a major stimulator of inflammation, bacterial lipopolysaccharide (LPS), on monocyte secretion of these mediators. Peripheral blood monocytes (PBM) were isolated by counterflow centrifugal elutriation from 15 healthy donors who were non-ST users. PBM were incubated for 24 hours in RPMI 1640 containing various concentrations of ST (0%, 0.005%, 0.01%, 1%) with or without 10 micrograms/ml LPS (Porphyromonas gingivalis LPS or Escherichia coli LPS). Of the ST preparations, only 1% ST resulted in PBM mediator secretion (7.7 +/- 2.0 ng/ml for PGE2 and 1.3 +/- 0.2 ng/ml for IL-1 beta) above that of control (unstimulated) cultures. Furthermore, the combination of 1% ST and LPS resulted in a potentiation of PGE2 release (5-fold for E. coli LPS + 1% ST and 10-fold for P. gingivalis LPS + 1% ST; P < 0.0001, one-way ANOVA) relative to the LPS preparations alone. In contrast, PBM IL-1 beta release decreased more than 2-fold upon E. coli LPS and 1% ST exposure, relative to treatment with E. coli LPS alone (P < 0.0001, one-way ANOVA).(ABSTRACT TRUNCATED AT 250 WORDS)

Gingival cell IL-2 and IL-4 in early-onset periodontitis.

The purpose of this study was to compare, using cell blot analysis, the association of gingival tissue mononuclear cells (GTMC) isolated from lesions displaying histories of early-onset periodontitis (EOP; typically B-lymphocyte dominated) and gingivitis (typically T-lymphocyte dominated) with the B-cell stimulating cytokine, interleukin (IL)-4, and the T-cell stimulating cytokine, IL-2. Eleven EOP patients and 11 age- and gender-similar gingivitis control (GC) subjects participated. Gingival tissue adjacent to the alveolar crest normally removed during surgery was digested in collagenase-containing media and GTMC were isolated by density gradient centrifugation. Cells were separated into four aliquots. One was left unstimulated; the remainder were stimulated for 2 hours with Porphyromonas gingivalis outer membrane protein, mitogen Concanavalin A, or common antigen tetanus toxoid. Cells then were centrifuged onto transfer membranes and incubated in RPMI 1640 media for 6 hours to allow absorption of secreted cytokine. Membranes were treated with monoclonal anti-IL-2 or anti-IL-4, followed by a biotin-conjugated second layer, streptavidin-alkaline phosphatase and nitro blue tetrazolium/5-bromo-4-chloro-indolyl-phosphate (NBT/BCIP) color development. A higher percentage of GTMC from EOP patients were IL-2+ when stimulated with P. gingivalis compared with GTMC from GC patients (20 +/- 2% vs. 12 +/- 2%, P < 0.003). A higher percentage of non-stimulated GTMC from EOP patients produced IL-4 than from GC (22 +/- 4% vs. 6 +/- 3%, P < 0.00007), as well as when stimulated with P. gingivalis (22 +/- 3% vs. 13 +/- 2%, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of estrogen and osteopenia/osteoporosis on clinical periodontitis in postmenopausal women.

BACKGROUND: In Western societies, more than one-third of the female population above age 65 suffers from signs and symptoms of osteoporosis, a disorder characterized by low bone mass. Estrogen deficiency is the dominant pathogenic factor for osteoporosis in women. The impact of estrogen deficiency and osteopenia/osteoporosis on periodontitis is unclear, partially due to the lack of longitudinal studies evaluating clinical signs of gingival inflammation and periodontitis progression. The purpose of this investigation was to analyze prospectively the influence of serum estradiol levels and osteopenia/osteoporosis on common clinical measurements of periodontal disease over a 2-year period. METHODS: Fifty-nine moderate/advanced adult periodontitis patients and 16 non-periodontitis subjects, all within 5 years after menopause at baseline, completed the study. Serum estradiol levels (E2) were measured yearly by 125I radioimmunoassay, and osteopenia/osteoporosis was determined by dual energy x-ray absorptiometry of the lumbar spine. Posterior interproximal clinical measurements were obtained every 6 months for the periodontitis patients, including explorer-detectable supragingival plaque, bleeding on probing (BOP) and relative clinical attachment level (RCAL). Baseline probing depths, smoking history, and demographic data also were collected. RESULTS: Data indicated that baseline demographic measurements and bone mineral density (BMD) of the lumbar spine were not different between E2-deficient and E2-sufficient subjects. Smoking activity (packs smoked/day, years smoked) was higher in periodontitis patients (P=0.0001). E2-sufficient periodontitis subjects had a higher frequency of supragingival plaque without increasing gingival inflammation. E2 status did not influence the percentage of sites losing RCAL for either periodontitis or non-periodontitis groups, but when non-smoking osteopenic/osteoporotic periodontitis patients were evaluated, E2-deficient subjects had more BOP (43.8% versus 24.4%, P<0.04) and a trend toward a higher frequency of > or =2.0 mm RCAL loss (3.8% versus 1.2%, P<0.1) than E2-sufficient subjects. CONCLUSIONS: These data suggest that E2 supplementation (serum E2>40 pg/ml) is associated with reduced gingival inflammation and a reduced frequency of clinical attachment loss in osteopenic/osteoporotic women in early menopause.

Longitudinal evaluation of peripheral blood monocyte secretory function in periodontitis-resistant and periodontitis-susceptible patients.

The purpose of this investigation was to evaluate lipopolysaccharide (LPS)-stimulated monocyte secretory responses longitudinally in patients with generalized severe chronic adult periodontitis (periodontitis-susceptible) and controls with gingivitis (periodontitis-resistant). In addition, the expression of constitutive (Leu-M3) and LPS-inducible (Mo3e) antigens on monocytes isolated from these two groups was examined. Monocyte secretory function was assessed longitudinally; the effect of periodontal therapy in the susceptible patients was examined by comparing monocyte function before and after their treatment. Peripheral blood monocytes were isolated by counterflow centrifugal elutriation and treated with control medium or media containing 1 microgram/ml of Salmonella typhimurium LPS or Prevotella intermedia LPS with or without human recombinant interferon (IFN)-gamma pretreatment. Prostaglandin E2, F2 alpha and thromboxane B2 were quantified in culture samples by gas chromatography-mass spectrometry (GC-MS) and interleukin-1 beta was quantified by enzyme-linked immunosorbent assay. Leu-M3 and Mo3e antigen expression was assessed by FACScan. Three major findings were made. First, LPS-stimulated IL-1 beta release by monocytes from susceptible patients was depressed relative to that in resistant patients at the initial donation. After periodontal therapy, there was virtually identical IL-1 beta release in LPS-stimulated cultures from both groups. However, in susceptible patients IL-beta release was diminished after periodontal therapy in cultures pretreated with IFN-gamma. Second, there was a significant drift in monocyte secretion of prostaglandin E2 in samples from the resistant patients between the first two donations and the third donation. PGE2 release did not differ between groups at the initial donation, although there was a depression in PGE2 release in the susceptible group at the final donation when IFN-gamma was followed by S. typhimurium LPS.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of distraction osteogenesis to induce new suprabony periodontal attachment in the beagle dog.

Using a technique called distraction osteogenesis (DO), orthopedic surgeons are capable of reconstructing 4 to 5 cm of bone and soft tissue without bone grafts or pedicle flap procedures. DO has been used recently to generate maxillofacial bone as an alternative to maxillary and mandibular osteotomies. Using DO methodology, this study attempted to regenerate supraalveolar buccal periodontium on the mandibular second, third, and fourth premolars of beagle dogs. A small but statistically significantly greater amount of new cementum was generated in experimental teeth, with no difference found between experimental and control groups with respect to regenerating alveolar bone. Further studies using modifications of this technique are warranted to explore the potential of DO as an alternative to conventional regenerative approaches.

Management of the gingival sulcus in fixed prosthodontics: a literature review and treatment protocol.

This review of the fixed prosthodontics and periodontology literature illustrates the influence of various factors on the health of the periodontium during and after fixed prosthodontic treatment. This article describes four categories of marginal finish lines for fixed prosthodontic restorations relative to the gingival margin and the epithelial attachment. The management of each category from both the periodontal and prosthodontic prespectives is also discussed.

Serum bone biomarkers and oral/systemic bone loss in humans.

UNLABELLED: We recently reported that subantimicrobial-dose doxycycline (SDD) significantly reduced serum bone-resorption biomarkers in subgroups of post-menopausal women. We hypothesize that changes in serum bone biomarkers are associated not only with systemic bone mineral density (BMD) changes, but also with alveolar bone changes over time. One hundred twenty-eight eligible post-menopausal women with periodontitis and systemic osteopenia were randomly assigned to receive SDD or placebo tablets twice daily for two years, adjunctive to periodontal maintenance. Sera were analyzed for bone biomarkers. As expected, two-year changes in a serum bone biomarker were significantly associated with systemic BMD loss at the lumbar spine (osteocalcin, bone-turnover biomarker, p = 0.0002) and femoral neck (osteocalcin p = 0.0025). Two-year changes in serum osteocalcin and serum pyridinoline-crosslink fragment of type I collagen (ICTP; bone-resorption biomarker) were also significantly associated with alveolar bone density loss (p < 0.0001) and alveolar bone height loss (p = 0.0008), respectively. Thus, we have shown that serum bone biomarkers are associated with not only systemic BMD loss, but with alveolar bone loss as well. CLINICAL TRIAL REGISTRATION INFORMATION: Protocol registered at ClinicalTrials.gov, NCT00066027.

Doxycycline effects on serum bone biomarkers in post-menopausal women.

We previously demonstrated that subantimicrobial-dose-doxycycline (SDD) treatment of post-menopausal osteopenic women significantly reduced periodontal disease progression, and biomarkers of collagen destruction and bone resorption locally in periodontal pockets, in a double-blind placebo-controlled clinical trial. We now hypothesize that SDD may also improve biomarkers of bone loss systemically in the same women, consistent with previous studies on tetracyclines (e.g., doxycycline) in organ culture and animal models of bone-deficiency disease. 128 post-menopausal osteopenic women with chronic periodontitis randomly received SDD or placebo tablets daily for 2 years adjunctive to periodontal maintenance therapy every 3-4 months. Blood was collected at baseline and at one- and two-year appointments, and sera were analyzed for bone resorption and bone formation/turnover biomarkers. In subsets of the study population, adjunctive SDD significantly reduced serum biomarkers of bone resorption (biomarkers of bone formation were unaffected), consistent with reduced risk of future systemic bone loss in these post-menopausal women not yet on anti-osteoporotic drugs.