Vasoactive intestinal polypeptide (VIP) and VPAC1 receptor in adult human dental pulp in relation to caries

Objective: To quantitatively measure VIP levels and to qualitatively study the distribution of VIP fibres and demonstrate the presence of the VPAC1 receptor in human dental pulp from carious and non-carious adult human teeth. Design: Dental pulp samples were collected from non-carious, moderately carious and grossly carious adult human teeth. VIP levels were determined using radioimmunoassay. The distribution of VIP fibres was studied using immunohistochemistry. The VPAC1 receptor protein expression was determined by Western blotting. Results: VIP levels were found to be significantly elevated in the dental pulp of moderately carious compared with non-carious (p = 0.0032) or grossly carious teeth (p = 0.0029). The distribution of VIP fibres was similar in non-carious and carious teeth, except that nerve bundles appeared thicker in the pulp samples from carious compared with non-carious teeth. Western blotting indicated that the VPAC1 receptor proteins were detected in similar levels in pooled dental pulp samples from both carious and non-carious teeth. Conclusion: It is concluded that quantitative changes in the levels of VIP in human dental pulp during the caries process and the expression of VPAC1 receptor proteins in membrane extracts from carious and non-carious teeth suggests a role for VIP in modulating pulpal health and disease. © 2006 Elsevier Ltd. All rights reserved.

Caries-induced changes in the expression of pulpal neuropeptide Y

Recent evidence suggests that the sympathetic nervous system may have a role in modulating neurogenic inflammation and bone remodelling. Neuropeptide Y (NPY) is a well-characterized neuropeptide transmitter in the peripheral sympathetic nervous system. NPY is known to be present in human dental pulp; however, quantitative data on NPY levels in pulpal health and disease in an adult population remain to be determined. The aims of the current study were to assess, quantitatively, NPY levels by radioimmunoassay and confirm the distribution of NPY fibres by immunocytochemistry in carious and non-carious adult human pulp tissue. Our results suggest changes in the levels and distribution of NPY in human dental pulp during the caries process, with significantly higher levels of NPY in carious compared with non-carious adult human teeth. Within the carious samples studied, our finding, that NPY levels were significantly elevated in mild/moderate caries, concurs with the hypothesis that NPY could have a modulatory role in pulpal inflammation and in reparative dentine formation. © 2006 Eur J Oral Sci.

Crossing forest thresholds: inertia and collapse in a Holocene sequence from south-central Spain

A Holocene palaeoecological sequence from Villaverde, south-central Spain, is presented. The pollen stratigraphy is used to infer past vegetation changes within a catchment area that represents the boundary between semi-arid, plateau and mountain vegetation. From c. 9700–7530 cal. yr BP, Pinus is dominant, probably as a result of a combination of a relatively dry climate and natural fire disturbance. From c. 7530–5900 cal. yr BP, moderate invasion by Quercus appears to be a migrational response following increased moisture and temperature, but in part shaped by competitive adjustments. From c. 5900–5000 cal. yr BP, the pine forests are replaced by deciduous-Quercus forests with an important contribution from Corylus, Betula, Fraxinus and Alnus. Mediterranean-type forests spread from c. 5000 to 1920 cal. yr BP coincident with expansions of Artemisia, Juniperus and other xerophytes. From c. 1920–1160 cal. yr BP, Pinus becomes dominant after a disturbance- mediated invasion of the oak forests. Human impact upon the regional landscape was negligible during the Neolithic, and limited in the Bronze and Iron Ages. Local deforestation and the expansion of agro-pastoral activities occur after c. 1600 cal. yr BP.

Persistently raised C-reactive protein levels are associated with advanced periodontal disease

Objective: The aim was to investigate whether there was an association between periodontitis or tooth loss in a homogeneous group of 60-70-year-old Western European men and either a sustained high or low level of C-reactive protein (CRP).
Material and Methods: Men enrolled in a cohort study of cardiovascular disease in Northern Ireland were screened in 1990-1994 and rescreened in 2001-2004, when a periodontal examination was completed. High-sensitivity CRP was measured from fasting blood samples. There were 806 men with six or more teeth who had either a high level (>3 mg/l) or a lower level of CRP at both time points. Multivariate analysis was carried out using logistic regression with adjustment for possible confounders. Models were constructed with the CRP level as the outcome variable and various measures of periodontal status (low and high threshold periodontitis) or tooth loss as predictor variables. Confounders included in the analysis were known cardiovascular risk factors of age, smoking, diabetes, BMI and socioeconomic status.
Results: There were 67 men who had a high value of CRP (>3 mg/l) and 739 men who had a CRP value =3 mg/l at both time points. The unadjusted odds ratio (OR) for advanced periodontitis to be associated with high CRP was 3.62, p=0.0003. The association was somewhat attenuated but remained significant (OR=2.49, p=0.02) after adjustment for confounders. A high level of tooth loss was also associated with high CRP with an adjusted OR of 2.17, p=0.008. Low threshold periodontitis was not associated with the level of CRP.
Conclusion: There was an association between advanced periodontitis and elevated CRP levels as measured at two time points at a 10-year interval in the 60-70-year-old European males investigated. This association was adjusted for various cardiovascular risk factors. There was also an association between high levels of tooth loss and high CRP in the men studied.

Antioxidants and periodontitis in 60-70 year- old men

Objective: The aim was to investigate the association between periodontal health and the serum levels of various antioxidants including carotenoids, retinol and vitamin E in a homogenous group of Western European men.
Materials and Methods: A representative sample of 1258 men aged 60-70 years, drawn from the population of Northern Ireland, was examined between 2001 and 2003. Each participant had six or more teeth, completed a questionnaire and underwent a clinical periodontal examination. Serum lipid-soluble antioxidant levels were measured by high-performance liquid chromatography with diode array detection. Multivariable analysis was carried out using logistic regression with adjustment for possible confounders. Models were constructed using two measures of periodontal status (low- and high-threshold periodontitis) as dependent variables and the fifths of each antioxidant as a predictor variable.
Results: The levels of a- and ß-carotene, ß-cryptoxanthin and zeaxanthin were highly significantly lower in the men with low-threshold periodontitis (p<0.001). These carotenoids were also significantly lower in high-threshold periodontitis. There were no significant differences in the levels of lutein, lycopene, a- and ?-tocopherol or retinol in relation to periodontitis. In fully adjusted models, there was an inverse relationship between a number of carotenoids (a- and ß-carotene and ß-cryptoxanthin) and low-threshold periodontitis. ß-Carotene and ß-cryptoxanthin were the only antioxidants that were associated with an increased risk of high-threshold severe periodontitis. The adjusted odds ratio for high-threshold periodontitis in the lowest fifth relative to the highest fifth of ß-cryptoxanthin was 4.02 (p=0.003).
Conclusion: It is concluded that low serum levels of a number of carotenoids, in particular beta-cryptoxanthin and beta-carotene, were associated with an increased prevalence of periodontitis in this homogenous group of 60-70-year-old Western European men.

Tooth loss and implant outcomes in patients refractory to treatment in a periodontal practice

Aim: The aim of this study was to investigate the factors associated with continued significant tooth loss due to periodontal reasons during maintenance following periodontal therapy in a specialist periodontal practice in Norway.
Material and Methods: A case-control design was used. Refractory cases were patients who lost multiple teeth during a maintenance period of 13.4 (range 8-19) years following definitive periodontal treatment in a specialist practice. Controls were age- and gender-matched maintenance patients from the same practice. Characteristics and treatment outcomes were assessed, and all teeth classified as being lost due to periodontal disease during follow-up were identified. The use of implants in refractory cases and any complications relating to such a treatment were recorded.
Results: Only 27 (2.2%) patients who received periodontal treatment between 1986 and 1998 in a specialist practice met the criteria for inclusion in the refractory to treatment group. Each refractory subject lost 10.4 (range 4-16) teeth, which represented 50% of the teeth present at baseline. The rate of tooth loss in the refractory group was 0.78 teeth per year, which was 35 times greater than that in the control group. Multivariate analysis indicated that being in the refractory group was predicted by heavy smoking (p=0.026), being stressed (p=0.016) or having a family history of periodontitis (p=0.002). Implants were placed in 14 of the refractory patients and nine (64%) of these lost at least one implant. In total, 17 (25%) of the implants placed in the refractory group were lost during the study period.
Conclusions: A small number of periodontal maintenance patients are refractive to treatment and go on to experience significant tooth loss. These subjects also have a high level of implant complications and failure. Heavy smoking, stress and a family history of periodontal disease were identified as factors associated with a refractory outcome.

Self-perception of dentofacial attractiveness among patients requiring orthognathic surgery

Objective: To test the hypothesis that the self-perception of dental and facial attractiveness among patients requiring orthognathic surgery is no different from that of control patients.

Materials and Methods: Happiness with dental and facial appearance was assessed using questionnaires completed by 162 patients who required orthognathic treatment and 157 control subjects. Visual analog scale, binary, and open response data were collected. Analysis was carried out using a general linear model, logistic regression, and chi-square tests.

Results: Orthognathic patients were less happy with their dental appearance than were controls. Class II patients and women had lower happiness scores for their dental appearance. Among orthognathic patients, the "shape" and "prominence" of their teeth were the most frequent causes of concern. Older subjects, women, and orthognathic patients were less happy with their facial appearance. Class III orthognathic patients, older subjects, and women were more likely to have looked at their own face in profile. A greater proportion of Class II subjects than Class III subjects wished to change their appearance.

Conclusions: The hypothesis is rejected. The findings indicate that women and patients requiring orthognathic surgery had lower levels of happiness with their dentofacial appearance. Although Class II patients exhibited the lowest levels of happiness with their dental appearance, there was some evidence that concerns and awareness about their facial profile were more pronounced among the Class III patients.

Serum Antibodies to Porphyromonas gingivalis Chaperone HtpG Predict Health in Periodontitis Susceptible Patients

Chaperones are ubiquitous conserved proteins critical in stabilization of new proteins, repair/removal of defective proteins and immunodominant antigens in innate and adaptive immunity. Periodontal disease is a chronic inflammatory infection associated with infection by Porphyromonas gingivalis that culminates in the destruction of the supporting structures of the teeth. We previously reported studies of serum antibodies reactive with the human chaperone Hsp90 in gingivitis, a reversible form of gingival disease confined to the oral soft tissues. In those studies, antibodies were at their highest levels in subjects with the best oral health. We hypothesized that antibodies to the HSP90 homologue of P. gingivalis (HtpG) might be associated with protection/resistance against destructive periodontitis.

The distribution of late-Quaternary woody taxa in northern Eurasia: evidence from a new macrofossil database

We present a database of late-Quaternary plant macrofossil records for northern Eurasia (from 23 degrees to 180 degrees E and 46 degrees to 76 degrees N) comprising 281 localities, over 2300 samples and over 13,000 individual records. Samples are individually radiocarbon dated or are assigned ages via age models fitted to sequences of calibrated radiocarbon dates within a section. Tree species characteristic of modern northern forests (e.g. Picea, Larix, tree-Betula) are recorded at least intermittently from prior to the last glacial maximum (LGM), through the LGM and Lateglacial, to the Holocene, and some records locate trees close to the limits of the Scandinavian ice sheet, supporting the hypothesis that some taxa persisted in northern refugia during the last glacial cycle. Northern trees show differing spatio-temporal patterns across Siberia: deciduous trees were widespread in the Lateglacial, with individuals occurring across much of their contemporary ranges, while evergreen conifers expanded northwards to their range limits in the Holocene. (c) 2009 Elsevier Ltd. All rights reserved.

PAR-2 Regulates Dental Pulp Inflammation Associated with Caries

Protease-activated receptors (PARs) are G-protein-coupled receptors that are activated enzymatically by proteolysis of an N-terminal domain. The cleavage and activation of PARs by serine proteases represent a novel mechanism by which such enzymes could influence the host inflammatory response. The aim of this study was to determine whether PAR-2 expression and activation were increased in dental caries. Using immunohistochemistry, we showed PAR-2 to be localized to pulp cells subjacent to caries lesions, but minimally expressed by healthy pulp tissue. Trypsin and the PAR-2 agonist (PAR2-AP) activated PAR-2 in an in vitro functional assay. Endogenous molecules present in pulp cell lysates from carious teeth specifically activated PAR-2, but those from healthy teeth failed to do so. The activation of PAR-2 in vitro was shown to increase the expression of the pro-inflammatory mediator cyclo-oxygenase-2 (COX-2), providing a mechanism whereby PAR-2 could modulate pulpal inflammation.

Long-term outcomes for cross-arch stabilizing bridges in periodontal maintenance patients - a retrospective study

Background: Cross-arch bridges are used to stabilize teeth for patients with reduced periodontal support. Little is known about technical or biological complications, whether teeth and implants can be combined in this type of bridge and the long-term effects on tooth loss.

Impaired Immune Tolerance to Porphyromonas gingivalis Lipopolysaccharide Promotes Neutrophil Migration and Decreased Apoptosis.

Periodontitis, a chronic inflammatory disease of the tissues supporting the teeth, is characterized by an exaggerated host immune and inflammatory response to periopathogenic bacteria. Toll-like receptor activation, cytokine network induction, and accumulation of neutrophils at the site of inflammation are important in the host defense against infection. At the same time, induction of immune tolerance and the clearance of neutrophils from the site of infection are essential in the control of the immune response, resolution of inflammation, and prevention of tissue destruction. Using a human monocytic cell line, we demonstrate that Porphyromonas gingivalis lipopolysaccharide (LPS), which is a major etiological factor in periodontal disease, induces only partial immune tolerance, with continued high production of interleukin-8 (IL-8) but diminished secretion of tumor necrosis factor alpha (TNF-) after repeated challenge. This cytokine response has functional consequences for other immune cells involved in the response to infection. Primary human neutrophils incubated with P. gingivalis LPS-treated naïve monocyte supernatant displayed a high migration index and increased apoptosis. In contrast, neutrophils treated with P. gingivalis LPS-tolerized monocyte supernatant showed a high migration index but significantly decreased apoptosis. Overall, these findings suggest that induction of an imbalanced immune tolerance in monocytes by P. gingivalis LPS, which favors continued secretion of IL-8 but decreased TNF- production, may be associated with enhanced migration of neutrophils to the site of infection but also with decreased apoptosis and may play a role in the chronic inflammatory state seen in periodontal disease.

Multiproxy evidence for terrestrial and aquatic ecosystem responses during the 8.2 ka cold event as recorded at Hojby So, Denmark

A sediment succession from Hojby So, a lake in eastern Denmark, covering the time period 9400-7400 cal yr BP was studied using high-resolution geochemistry, magnetic susceptibility, pollen, macrofossil, diatom, and algal pigment analysis to investigate responses of the terrestrial and aquatic ecosystems to the 8.2 ka cold event. A reduced pollen production by thermophilous deciduous tree taxa in the period c. 8250-8000 cal yr BP reveal that the forest ecosystem was affected by low temperatures during the summer and winter/early-spring seasons. This finding is consistent with the timing of the 8.2 ka cold event as registered in the Greenland ice cores. At Hojby So, the climate anomaly appears to have started 200-250 yr earlier than the 8.2 ka cold event as the lake proxy data provide strong evidence for a precipitation-induced distinct increase in catchment soil erosion beginning around 8500 cal yr BP. Alteration of the terrestrial environment then resulted in a major aquatic ecosystem change with nutrient enrichment of the lake and enhanced productivity, which lasted until c. 7900 cal yr BP. (C) 2009 University of Washington. Published by Elsevier Inc. All rights reserved.

Quantification of all-ceramic crown margin surface profile from try-in to 1-week post-cementation

To use profilometry to assess the margin surface profile of all-ceramic crowns (ACC’s) at try-in and 1-week after cementation with dual-cured resin (DC, RelyX ARC, 3 M ESPE, St. Paul, MN, USA), self-adhesive dual-cured resin (SADC, RelyX Unicem, 3 M ESPE), light-cured resin (LC, RelyX Veneer, 3 M ESPE) or chemically cured resin-modified glass ionomer (RMGI, RelyX Luting Plus, 3 M ESPE) luting cement. Methods: Forty, sound, extracted, human, premolar teeth underwent a standardised preparation for ACC’s. IPS Empress (Ivoclar-Vivadent, Liechtenstein) crowns of standard dimensions were fabricated and 10 luted with each cement and stored in water for 7 days. Three groups of serial profiles were taken, the first of the tooth preparation, the second of the crown margins at try-in and lastly of the crown margins after cementation and 7 days water storage. Results: There were no significant differences in the crown margin surface profile between the four cement groups at try-in. The change in crown margin position between try-in and post-cementation was significantly greater for DC than for LC and RMGI. SADC was not significantly different to the other cements. There were no significant differences in the crown margin extensions between the four cement groups, however most of the IPS Empress ACC’s in this study were underextended but this was not statistically significant. Conclusions: IPS Empress ACC’s seated more fully with LC and RMGI than with DC cement

Human odontoblasts express functional thermo-sensitive TRP channels: implications for dentin sensitivity

Odontoblasts form the outermost cellular layer of the dental pulp where they have been proposed to act as sensory receptor cells. Despite this suggestion, evidence supporting their direct role in mediating thermo-sensation and nociception is lacking. Transient receptor potential (TRP) ion channels directly mediate nociceptive functions, but their functional expression in human odontoblasts has yet to be elucidated. In the present study, we have examined the molecular and functional expression of thermo-sensitive TRP channels in cultured odontoblast-like cells and in native human odontoblasts obtained from healthy wisdom teeth. PCR and western blotting confirmed gene and protein expression of TRPV1, TRPA1 and TRPM8 channels. Immunohistochemistry revealed that these channels were localised to odontoblast-like cells as determined by double staining with dentin sialoprotein (DSP) antibody. In functional assays, agonists of TRPV1, TRPA1 and TRPM8 channels elicited [Ca2+]i transients that could be blocked by relevant antagonists. Application of hot and cold stimuli to the cells also evoked rises in [Ca2+]i which could be blocked by TRP-channel antagonists. Using a gene silencing approached we further confirmed a role for TRPA1 in mediating noxious cold responses in odontoblasts. We conclude that human odontoblasts express functional TRP channels that may play a crucial role in mediating thermal sensation in teeth. Cultured and native human odontoblasts express functional TRP channels that may play a crucial role in mediating thermal sensation in teeth.