Ground deformation reveals the scale-invariant conduit dynamics driving explosive basaltic eruptions.

The mild activity of basaltic volcanoes is punctuated by violent explosive eruptions that occur without obvious precursors. Modelling the source processes of these sudden blasts is challenging. Here, we use two decades of ground deformation (tilt) records from Stromboli volcano to shed light, with unprecedented detail, on the short-term (minute-scale) conduit processes that drive such violent volcanic eruptions. We find that explosive eruptions, with source parameters spanning seven orders of magnitude, all share a common pre-blast ground inflation trend. We explain this exponential inflation using a model in which pressure build-up is caused by the rapid expansion of volatile-rich magma rising from depth into a shallow (<400 m) resident magma conduit. We show that the duration and amplitude of this inflation trend scales with the eruption magnitude, indicating that the explosive dynamics obey the same (scale-invariant) conduit process. This scale-invariance of pre-explosion ground deformation may usher in a new era of short-term eruption forecasting.

The Subgingival Microbiome Relationship to Periodontal Disease in Older Women.

Understanding of the oral microbiome in relation to periodontal disease in older adults is limited. The composition and diversity of the subgingival microflora and their oligotypes in health and levels of periodontal disease were investigated in this study on older postmenopausal women. The 16S rRNA gene was sequenced using the Illumina MiSeq platform in 1,206 women aged 53 to 81 y. Presence and severity of periodontal disease were defined by Centers for Disease Control and Prevention/American Academy of Periodontology criteria. Composition of the microbiome was determined by 16S rRNA amplicon sequencing and the abundance of taxa described by the centered log2-ratio (CLR) transformed operational taxonomic unit (OTU) values. Differences according to periodontal disease status were determined by analysis of variance with Bonferroni correction. Bacteria oligotypes associated with periodontal disease and health were determined by minimum entropy decomposition and their functions estimated in silico using PICRUSt. Prevalence of none/mild, moderate, and severe periodontal disease was 25.1%, 58.3%, and 16.6%, respectively. Alpha diversity of the microbiome differed significantly across the 3 periodontal disease categories. ß-Diversity differed between no/mild and severe periodontal disease, although considerable overlap was noted. Of the 267 bacterial species identified at ≥0.02% abundance, 56 (20.9%) differed significantly in abundance according to periodontal disease status. Significant linear correlations for pocket depth and clinical attachment level with bacterial amounts were observed for several taxa. Of the taxa differing in abundance according to periodontal disease status, 53% had multiple oligotypes appearing to differ between none/mild and severe periodontal disease. Among older women, taxonomic differences in subgingival microbiome composition and diversity were observed in relation to clinical periodontal disease measures. Potential differences in bacterial subspecies (oligotypes) and their function were also identified in periodontal disease compared with health.

Tannerella forsythia-produced methylglyoxal causes accumulation of advanced glycation endproducts to trigger cytokine secretion in human monocytes.

The periodontal pathogen Tannerella forsythia has the unique ability to produce methylglyoxal (MGO), an electrophilic compound which can covalently modify amino acid side chains and generate inflammatory adducts known as advanced glycation endproducts (AGEs). In periodontitis, concentrations of MGO in gingival-crevicular fluid are increased and are correlated with the T. forsythia load. However, the source of MGO and the extent to which MGO may contribute to periodontal inflammation has not been fully explored. In this study we identified a functional homolog of the enzyme methylglyoxal synthase (MgsA) involved in the production of MGO in T. forsythia. While wild-type T.forsythia produced a significant amount of MGO in the medium, a mutant lacking this homolog produced little to no MGO. Furthermore, compared with the spent medium of the T. forsythia parental strain, the spent medium of the T. forsythia mgsA-deletion strain induced significantly lower nuclear factor-kappa B activity as well as proinflammogenic and pro-osteoclastogenic cytokines from THP-1 monocytes. The ability of T. forsythia to induce protein glycation endproducts via MGO was confirmed by an electrophoresis-based collagen chain mobility shift assay. Together these data demonstrated that T. forsythia produces MGO, which may contribute to inflammation via the generation of AGEs and thus act as a potential virulence factor of the bacterium.

A Randomized Clinical Trial Evaluating rh-FGF-2/ß-TCP in Periodontal Defects.

Biological mediators have been used to enhance periodontal regeneration. The aim of this prospective randomized controlled study was to evaluate the safety and effectiveness of 3 doses of fibroblast growth factor 2 (FGF-2) when combined with a ß-tricalcium phosphate (ß-TCP) scaffold carrier placed in vertical infrabony periodontal defects in adult patients. In this double-blinded, dose-verification, externally monitored clinical study, 88 patients who required surgical intervention to treat a qualifying infrabony periodontal defect were randomized to 1 of 4 treatment groups-ß-TCP alone (control) and 0.1% recombinant human FGF-2 (rh-FGF-2), 0.3% rh-FGF-2, and 0.4% rh-FGF-2 with ß-TCP-following scaling and root planing of the tooth prior to a surgical appointment. Flap surgery was performed with EDTA conditioning of the root prior to device implantation. There were no statistically significant differences in patient demographics and baseline characteristics among the 4 treatment groups. When a composite outcome of gain in clinical attachment of 1.5 mm was used with a linear bone growth of 2.5 mm, a dose response pattern detected a plateau in the 0.3% and 0.4% rh-FGF-2/ß-TCP groups with significant improvements over control and 0.1% rh-FGF-2/ß-TCP groups. The success rate at 6 mo was 71% in the 2 higher-concentration groups, as compared with 45% in the control and lowest treatment groups. Percentage bone fill in the 2 higher-concentration groups was 75% and 71%, compared with 63% and 61% in the control and lowest treatment group. No increases in specific antibody to rh-FGF-2 were detected, and no serious adverse events related to the products were reported. The results from this multicenter trial demonstrated that the treatment of infrabony vertical periodontal defects can be enhanced with the addition of rh-FGF-2/ß-TCP (ClinicalTrials.gov NCT01728844).

A tribute to Marty Taubman: the Earl of Sandwich, IgA, T-regs, and the Celtics.

This tribute to Marty Taubman is written on the occasion of his retirement from full-time faculty status at The Forsyth Institute and Harvard Dental School, and his stepping down as editor of the "Discovery!" section of the Journal of Dental Research. It recognizes his seminal contributions to oral immunology, his mentoring of a generation of new scientists, his key role as a leader in organized research as president of the American Association for Dental Research, as well as his editorship, which has recognized scores of his colleagues in science. He is a leader in our field and has made many lasting contributions to research, teaching, and our profession, for which we are very grateful.

Self-reported measures for surveillance of periodontitis.

The purpose of this study was to evaluate the performance of self-reported measures in predicting periodontitis in a representative US adult population, based on 2009-2010 National Health and Nutrition Examination Survey (NHANES) data. Self-reported gum health and treatment history, loose teeth, bone loss around teeth, tooth not looking right, and use of dental floss and mouthwash were obtained during in-home interviews and validated against full-mouth clinically assessed periodontitis in 3,743 US adults 30 years and older. All self-reported measures (> 95% item response rates) were associated with periodontitis, and bivariate correlations between responses to these questions were weak, indicating low redundancy. In multivariable logistic regression modeling, the combined effects of demographic measures and responses to 5 self-reported questions in predicting periodontitis of mild or greater severity were 85% sensitive and 58% specific and produced an 'area under the receiver operator characteristic curve' (AUROCC) of 0.81. Four questions were 95% sensitive and 30% specific, with an AUROCC of 0.82 in predicting prevalence of clinical attachment loss ≥ 3 mm at one or more sites. In conclusion, self-reported measures performed well in predicting periodontitis in US adults. Where preferred clinically based surveillance is unattainable, locally adapted variations of these self-reported measures may be a promising alternative for surveillance of periodontitis.

Prevalence of periodontitis in adults in the United States: 2009 and 2010.

This study estimated the prevalence, severity, and extent of periodontitis in the adult U.S. population, with data from the 2009 and 2010 National Health and Nutrition Examination Survey (NHANES) cycle. Estimates were derived from a sample of 3,742 adults aged 30 years and older, of the civilian non-institutionalized population, having 1 or more natural teeth. Attachment loss (AL) and probing depth (PD) were measured at 6 sites per tooth on all teeth (except the third molars). Over 47% of the sample, representing 64.7 million adults, had periodontitis, distributed as 8.7%, 30.0%, and 8.5% with mild, moderate, and severe periodontitis, respectively. For adults aged 65 years and older, 64% had either moderate or severe periodontitis. Eighty-six and 40.9% had 1 or more teeth with AL ≥ 3 mm and PD ≥ 4 mm, respectively. With respect to extent of disease, 56% and 18% of the adult population had 5% or more periodontal sites with ≥ 3 mm AL and ≥ 4 mm PD, respectively. Periodontitis was highest in men, Mexican Americans, adults with less than a high school education, adults below 100% Federal Poverty Levels (FPL), and current smokers. This survey has provided direct evidence for a high burden of periodontitis in the adult U.S. population.

Single nucleotide polymorphisms of pattern recognition receptors and chronic periodontitis.

BACKGROUND AND OBJECTIVE: Periodontitis is a multifactorial disease influenced partly by genetics. Activation of pattern recognition receptors (PRRs) can lead to the up-regulation of inflammatory pathways, resulting in periodontal tissue destruction. Hence, functional polymorphisms located in PRRs can explain differences in host susceptibility to periodontitis. This study investigated single nucleotide polymorphisms of PRRs including toll-like receptor (TLR)2 (G2408A), TLR4 (A896G), TLR9 (T1486C), TLR9 (T1237C) and CD14 (C260T) in patients with chronic periodontitis and in periodontally healthy subjects. METHODS: One-hundred and fourteen patients with chronic periodontitis and 77 periodontally healthy subjects were genotyped using TaqMan® allelic discrimination assays. Fisher's exact test and chi-square analyses were performed to compare genotype and allele frequencies. RESULTS: The frequency of subjects with the CC genotype of CD14 (C260T) (24.6% in the chronic periodontitis group vs. 13% in the periodontally healthy group) and those expressing the T allele of CD14 (C260T) (CT and TT) (75.4% in the chronic periodontitis group vs. 87% in the periodontally healthy group) was statistically different among groups (p = 0.04). Homozygocity for the C allele of the CD14 (C260T) polymorphism (CC) was associated with a two--fold increased susceptibility to periodontitis (p = 0.04; odds ratio, 2.49; 95% confidence interval, 1.06-6.26). Individuals with the CC genotype of TLR9 (T1486C) (14.9% in the chronic periodontitis group vs. 28.6% in the periodontally healthy group) and those expressing the T allele of TLR9 (T1486C) (CT and TT) (85.1% in the chronic periodontitis group vs. 71.4% in the periodontally healthy group) were also significantly differently distributed between groups without adjustment (p = 0.03). Further analysis of nonsmokers revealed a significant difference in the distribution of genotypes between groups for TLR9 (T1486C; p = 0.017) and CD14 (C260T; p = 0.03), polymorphisms again without adjustment. CONCLUSION: The CC genotype of CD14 (C260T) is related to susceptibility to chronic periodontitis in Caucasians. In addition, differences observed in the distribution of TLR9 (T1486C) genotypes between groups warrant further investigation.

Perineural infusion of 0.5% ropivacaine for successful treatment of phantom limb syndrome: a case report.

Phantom limb syndrome (PLS) comprises various disturbances, including pain in the missing limb and phantom sensations. This study is about the successful treatment of a PLS patient by prolonged infusion of local anesthetic through a perineural catheter. A 45-year-old man came to the Rizzoli Orthopedic Institute (Bologna, Italy) complaining of a painful right leg after trauma. Complex regional pain syndrome (CRPS) type II was diagnosed. Therapy with tricyclics, gabapentin, and spinal infusion of morphine was started. After 4 years of treatment, infection led to the need for right below-the-knee amputation. After amputation, PLS appeared immediately and was not responsive to pharmacological treatment. At day II, a perineural sciatic catheter was positioned and 0.5% ropivacaine infusion with an elastomeric pump at 5 mL/h was started. The infusion was temporarily discontinued every week to evaluate the PLS. After 7 days, a 30% reduction in pain was observed, increased to 60% after 14 days, and disappeared completely after 21 days, leaving only the phantom limb sensations. After 28 days of continuous infusion, the phantom limb sensations had also disappeared. The perineural catheter was removed after 48 hours without perineural infusion. The patient was weaned from morphine over 150 days. Follow-ups at 6, 12, 24, and 36 months confirmed that the PLS did not reappear. The results are limited to one patient but are encouraging, particularly due to the relevance of the pathology and the poor results of conventional treatments. More cases are obviously needed to support the efficacy of this therapy.

Osteoporosis and oral infection: independent risk factors for oral bone loss.

Studies have suggested that oral bone loss is independently influenced by local and systemic factors, including osteoporosis. This cross-sectional study of 1256 post-menopausal women, recruited from the Buffalo center of the Women's Health Initiative Observational Study, evaluated the influence of oral infection and age on the associations between osteoporosis and oral bone loss. Systemic bone density was measured by dual-energy x-ray absorptiometry. Alveolar crestal height was measured from standardized dental radiographs. Oral infection was assessed from subgingival plaque samples. Total forearm density [beta (SE)= -0.931 (0.447), p=0.038] and presence of Tannerella forsythensis [beta (SE)=0.125 (0.051), p=0.015] were independently associated with mean alveolar height among women aged <70 years after confounder adjustment. Women aged 70+ years had worse oral bone loss, in general, but neither bone density nor oral infection was significantly associated with mean alveolar height in this age group. Systemic bone density and oral infection independently influenced oral bone loss in post-menopausal women aged <70 years.

Periodontal infections contribute to elevated systemic C-reactive protein level.

BACKGROUND: Periodontitis is a local inflammatory process mediating destruction of periodontal tissues triggered by bacterial insult. However, this disease is also characterized by systemic inflammatory host responses that may contribute, in part, to the recently reported higher risk for cardiovascular disease (CVD) among patients with periodontitis. Moderate elevation of C-reactive protein (CRP) has been found to be a predictor of increased risk for CVD. Elevated CRP levels in periodontal patients have been reported by several groups. In this study, we examined whether CRP plasma levels are increased in periodontitis and if there is a relation to severity of periodontal disease and to the periodontal microflora. METHODS: CRP serum levels were assessed using radial immunodiffusion assay in 174 subjects, 59 with moderate mean clinical attachment loss (AL) (2.39+/-0.29 mm) and 50 with high AL (3.79+/-0.86 mm) as compared to 65 periodontally healthy controls (AL, 1.74+/-0.18 mm). Clinical attachment loss, probing depths, and percentage of periodontal pocket sites > or =5 mm were measured. The presence of periodontal pathogens Porphyromonas gingivalis (P.g.), Prevotella intermedia (P.i.), Campylobacter recta (C.r.), and Bacteroides forsythus (B.f.) in subgingival plaque samples was measured by immunofluorescence microscopy. RESULTS: Statistically significant increases in CRP levels were observed in subjects with periodontal disease when compared to healthy controls (P= 0.036). Subjects with high levels of mean clinical attachment loss had significantly higher mean CRP levels (4.06+/-5.55 mg/l) than controls (1.70+/-1.91 mg/l), P= 0.011. The CRP levels were adjusted for factors known to be associated with elevated CRP, including age, smoking, body mass index (BMI), triglycerides, and cholesterol. Age and BMI were found to be significant covariates. The reported range for CRP as a risk factor for CVD, peripheral vascular diseases, or stroke is 1.34 mg/l to 6.45 mg/l and the mean of this range is 3 mg/l. The percentage of subjects with elevated levels of CRP > or = 3 mm was significantly higher in the high clinical AL group (38%; 95% Cl: 26.7%, 49.3%) when compared to the control group (16.9%; 95% CI: 9.25%, 24.5%), P= 0.011. The presence of periodontal pathogens P.g., P.i., C.r., and B.f. in subgingival samples was positively associated with elevated CRP levels (P= 0.029). CONCLUSIONS: The extent of increase in CRP levels in periodontitis patients depends on the severity of the disease after adjusting for age, smoking, body mass index, triglycerides, and cholesterol. Also, there are elevated levels of CRP associated with infection with subgingival organisms often associated with periodontal disease, including P.g., P.i., C.r., and B.f. Recent investigations emphasized the role of moderate elevated CRP plasma levels as a risk factor for CVD. The positive correlation between CRP and periodontal disease might be a possible underlying pathway in the association between periodontal disease and the observed higher risk for CVD in these patients.

Development of a gene inactivation system for Bacteroides forsythus: construction and characterization of a BspA mutant.

Bacteroides forsythus is a gram-negative anaerobic bacterium associated with periodontitis. The bspA gene encoding a cell surface associated leucine-rich repeat protein (BspA) involved in adhesion to fibronectin and fibrinogen was recently cloned from this bacterium in our laboratory. We now describe the construction of a BspA-defective mutant of B. forsythus. This is the first report describing the generation of a specific gene knockout mutant of B. forsythus, and this procedure should be useful in establishing the identity of virulence-associated factors in these organisms.

Fimbriae of Porphyromonas gingivalis induce opsonic antibodies that significantly enhance phagocytosis and killing by human polymorphonuclear leukocytes.

Porphyromonas gingivalis has been strongly implicated in the pathogenesis of human periodontitis. Fimbriae mediate adherence and colonization of the oral cavity by this organism and may, therefore, have potential for use as antigen in an anti-P. gingivalis vaccine. The purpose of our study was to determine whether P. gingivalis fimbriae have opsonic target sites and whether they are accessible on the cell surfaces and cross-reactive among P. gingivalis fimbrial types and serotypes. Rabbits were immunized with a vaccine. The antiserum reacted with a 43-kDa fimbrillin monomer and a 43-kDa component in whole-cell sonicates of P. gingivalis 33277, but it showed only very weak reactivity in the 43-kDa region of Western blots of a whole-cell sonicate of strain DPG3, a mutant that does not express functional fimbriae. The antibody enhanced chemiluminescence approximately six-fold relative to preimmune serum values and significantly enhanced phagocytosis and killing of P. gingivalis 33277 by human polymorphonuclear leukocytes. Peak opsonic activity was observed at week 6 followed by a plateau that remained until week 16. The fimbria-deficient mutant DPG3 did not bind antifimbrial antibody and was not opsonized, whereas strain 381, the parent of the mutant, was opsonized. The specific antibody bound to and opsonized P. gingivalis strains 33277 and 381 (fimbria type I) but not W50, A7A-1-28, 9-14K-1 or FAY-19M-1 (fimbrial types II-V). Specific antibody bound to strain 2561 (fimbrial type I) but, as assessed by chemiluminescence, did not opsonize it. While fimbriae have opsonic target sites that are accessible on P. gingivalis cell surfaces, the relevant opsonic target sites do not appear to be shared across serotypes or fimbrial types. Thus, a vaccine containing, as antigen, fimbrial protein from a single P. gingivalis strain would likely be ineffective against infections by P. gingivalis strains expressing other fimbrial types.

Oral immunization with recombinant Streptococcus gordonii expressing porphyromonas gingivalis FimA domains.

Porphyromonas gingivalis, a gram-negative anaerobe, is implicated in the etiology of adult periodontitis. P. gingivalis fimbriae are one of several critical surface virulence factors involved in both bacterial adherence and inflammation. P. gingivalis fimbrillin (FimA), the major subunit protein of fimbriae, is considered an important antigen for vaccine development against P. gingivalis-associated periodontitis. We have previously shown that biologically active domains of P. gingivalis fimbrillin can be expressed on the surface of the human commensal bacterium Streptococcus gordonii. In this study, we examined the effects of oral coimmunization of germfree rats with two S. gordonii recombinants expressing N (residues 55 to 145)- and C (residues 226 to 337)-terminal epitopes of P. gingivalis FimA to elicit FimA-specific immune responses. The effectiveness of immunization in protecting against alveolar bone loss following P. gingivalis infection was also evaluated. The results of this study show that the oral delivery of P. gingivalis FimA epitopes via S. gordonii vectors resulted in the induction of FimA-specific serum (immunoglobulin G [IgG] and IgA) and salivary (IgA) antibody responses and that the immune responses were protective against subsequent P. gingivalis-induced alveolar bone loss. These results support the potential usefulness of the S. gordonii vectors expressing P. gingivalis fimbrillin as a mucosal vaccine against adult periodontitis.

The effect of alcohol consumption on periodontal disease.

BACKGROUND: Alcohol consumption, like smoking, may be related to periodontal disease independently of oral hygiene status. This study assessed the relationship between alcohol consumption and severity of periodontal disease. METHODS: A cross-sectional study of 1,371 subjects ages 25 to 74 in the Erie County, NY population was performed. Alcohol intake was assessed by means of previously validated self-reported questionnaires. Outcome variables were gingival bleeding, clinical attachment loss, alveolar bone loss, and presence of subgingival microorganisms. RESULTS: Logistic regression analyses adjusting for age, gender, race, education, income, smoking, diabetes mellitus, dental plaque, and presence of any of 8 subgingival microorganisms showed that those consuming > or =5 drinks/week had an odds ratio (OR) of 1.65 (95% CI: 1.22 to 2.23) of having higher gingival bleeding, and OR of 1.36 (95% CI: 1.02 to 1.80) of having more severe clinical attachment loss compared to those consuming <5 drinks/week. Those consuming > or =10 drinks/week had an odds ratio (OR) of 1.62 (95% CI: 1.12 to 2.33) of having higher gingival bleeding and OR of 1.44 (95% CI: 1.04 to 2.00) of having more severe clinical attachment loss compared to those consuming <10 drinks/week. Alcohol consumption was not significantly related to alveolar bone loss nor to any of the subgingival microorganisms. CONCLUSIONS: The results suggest that alcohol consumption is associated with moderately increased severity of periodontal disease. Longitudinal studies are needed to determine whether alcohol is a true risk factor for periodontal disease.

An economic evaluation of a chlorhexidine chip for treating chronic periodontitis: the CHIP (chlorhexidine in periodontitis) study.

BACKGROUND: The authors previously suggested that an adjunctive, controlled-release chlorhexidine, or CHX, chip may reduce periodontal surgical needs at little additional cost. This article presents an economic analysis of the CHX chip in general dental practice. METHODS: In a one-year prospective clinical trial, 484 chronic periodontitis patients in 52 general practices across the United States were treated with either scaling and root planing, or SRP, plus any therapy prescribed by treating, unblinded dentists; or SRP plus other therapy as above but including the CHX chip. Economic data were collected from bills, case report forms and 12-month treatment recommendations from blinded periodontist evaluators. RESULTS: Total dental charges were higher for SRP + CHX chip patients vs. SRP patients when CHX chip costs were included (P = .027) but lower when CHX chip costs were excluded (P = .012). About one-half of the CHX chip acquisition cost was offset by savings in other charges. SRP + CHX chip patients were about 50 percent less likely to undergo surgical procedures than were SRP patients (P = .021). At the end of the trial, periodontist evaluators recommended similar additional procedures for both groups: SRP, about 46 percent; maintenance, about 37 percent; surgery, 56 percent for SRP alone and 63 percent for SRP + CHX chip. CONCLUSIONS: Adjunctive CHX chip use for general-practice patients with periodontitis increased costs but reduced surgeries over one year. At study's end, periodontists recommended similar additional surgical treatment for both groups. CLINICAL IMPLICATIONS: In general practice, routine use of the CHX chip suggests that costs will be partially offset by reduced surgery over at least one year.