Kristina Bertl

Effects of enamel matrix derivative on proliferation/viability, migration, and expression of angiogenic factor and adhesion molecules in endothelial cells in vitro.

BACKGROUND The aim of this study was to test in vitro the effect of enamel matrix derivative (EMD) on the proliferation/viability, migration, and expression of angiogenic factor and adhesion molecules in human umbilical vein endothelial cells (HUVECs). To date, discussions on angiogenic effects of EMD are rather controversial. METHODS The effect of EMD on the proliferation/viability of HUVECs after 24 hours was measured using 3,4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide (MTT) assay and direct cell counting. Cell migration was observed in an especially adapted in vitro monolayer wound-healing model. The expression of angiogenic factor angiopoietin-2 (ang-2) and adhesion molecules intercellular adhesion molecule (ICAM)-1 and vascular endothelium-selectin (E-selectin) was quantified with real-time polymerase chain reaction (PCR). RESULTS The proliferation/viability of HUVECs measured in MTT assay was stimulated by 0.1 microg/ml EMD and inhibited by higher doses (50 to 100 microg/ml), but the total number of cells was not affected. Cell migration in the wound-healing assay was promoted by EMD at doses of 0.1 to 50 microg/ml and inhibited at 100 microg/ml. The highest expression level of all three tested genes (ICAM-1, E-selectin, and ang-2) was observed at 50 microg/ml EMD. CONCLUSION The results of the present in vitro study show the potential influence of EMD on the angiogenic activity of HUVECs, which may play an important role in periodontal tissue regeneration and wound healing.

Microbial analysis of subgingival plaque samples compared to that of whole saliva in patients with periodontitis.

BACKGROUND The detection of special bacterial species in patients with periodontitis is considered to be useful for clinical diagnosis and treatment. The collection of subgingival plaque samples is the common way for the determination of periodontopathic bacteria. However, recently, salivary analysis has been discussed as an advantageous future diagnostic method for periodontitis because it offers simple quantitative sampling and the possibility to assess various bacteria. The aim of this cross-sectional study is to investigate whether there is a correlation between the results of different bacterial species in saliva and subgingival plaque samples from individuals with aggressive periodontitis (AgP) and chronic periodontitis (CP). METHODS Whole saliva and subgingival plaque samples from the deepest pocket of each quadrant were collected from 43 patients with CP and 33 patients with AgP. Twenty different bacterial species from both samplings were determined by the 16S ribosomal RNA-based polymerase chain reaction with microarray technique. RESULTS All bacterial species were detected in salivary and subgingival plaque samples. For Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia, as well as Actinomyces viscosus, Campylobacter rectus/showae, Prevotella intermedia, Parvimonas micra, Eubacterium nodatum, and Campylobacter gracilis, a significant positive correlation between salivary and subgingival plaque samples was detected in patients with both types of periodontitis. There were no significant differences in bacteria in salivary and subgingival plaque samples between AgP and CP. CONCLUSION Salivary analysis might be discussed as a potential alternative to subgingival plaque sampling for microbiologic analysis in both AgP and CP.

Nitric oxide production, systemic inflammation and lipid metabolism in periodontitis patients: possible gender aspect

AIM Nitric oxide (NO) plays a crucial role in vascular tone regulation and is involved in pathogenesis of periodontitis. In this cross-sectional study, we investigated the serum and saliva levels of NO metabolites in periodontal disease and their relationship with serum C-reactive protein (CRP) levels, lipids metabolism and periodontal disease severity. MATERIAL AND METHODS Serum and saliva were collected from non-smoking patients with generalized severe periodontitis (n = 89) and healthy controls (n = 56). Serum and salivary levels of NO metabolites, serum levels of high density lipoproteins (HDL), low density lipoproteins (LDL), triglycerides, cholesterol and CRP were measured. Data were analysed in whole population and in different gender groups. RESULTS Periodontitis patients exhibited significantly lower serum and saliva levels of NO metabolites and significantly higher LDL, cholesterol and CRP levels than control group. Similar findings were observed within male but not within female population. Serum NO metabolites levels exhibited significant negative correlation with CRP in whole population and in male population. Significant positive correlation of serum NO metabolite levels with HDL levels was observed in whole population. CONCLUSION NO production is reduced in periodontitis, especially in male population. Gender might be an important factor in assessing risk of cardiovascular disease in periodontitis.

Hyaluronan in non‐surgical and surgical periodontal therapy: a systematic review

AIM To evaluate the effect of hyaluronan (HY) application as monotherapy or as adjunct to non-surgical and/or surgical periodontal therapy. METHODS Literature search was performed according to PRISMA guidelines with the following main eligibility criteria: (a) English or German language; (b) pre-clinical in vivo or human controlled trials; (c) effect size of HY evaluated histologically or clinically. RESULTS Two pre-clinical in vivo studies on surgical treatment and 12 clinical trials on non-surgical and/or surgical treatment were included. Most of the studies were highly heterogeneous, regarding with HY product used and application mode, and of high risk of bias, thus not allowing meta-analysis. The majority of clinical studies described a beneficial, occasionally statistically significant, effect of HY on bleeding on probing (BoP) and pocket depth (PD) reduction (2.28-19.5% and 0.2-0.9 mm, respectively), comparing to controls; no adverse effects were reported. CONCLUSIONS Hyaluronan application as adjunct to non-surgical and surgical periodontal treatment seems to have a beneficial, generally moderate, effect on surrogate outcome variables of periodontal inflammation, i.e., BoP and residual PD, and appears to be safe. The large heterogeneity of included studies, does not allow recommendations on the mode of application or effect size of HY as adjunct to non-surgical and surgical periodontal treatment.

Anaerobic and microaerophilic pathogens in the biofilm formation on voice prostheses: A pilot study†

Voice rehabilitation with voice prostheses is a standard therapy in laryngectomized patients. Biofilm formation on the surface of the voice prostheses causes device failure and requires frequent replacements. Studies analyzing the biofilm of voice prostheses have mainly focused on aerobic bacteria. Anaerobic bacteria as an integral part of the biofilms on voice prostheses have not been investigated yet.

The occurrence of dental caries is associated with atherosclerosis

OBJECTIVE: Previous studies have suggested that marginal periodontitis is a risk factor for developing atherosclerosis. The objective of this study was to determine whether caries may also be associated with atherosclerosis. METHODS: The computed tomography data sets of 292 consecutive patients, 137 women and 155 men with a mean age of 54.1±17.3 years, were analyzed. Caries were quantified based on the number of decayed surfaces of all the teeth, and periodontitis was quantified on the basis of the horizontal bone loss in the jaw. The presence of chronic apical periodontitis (CAP) was assessed, and the aortic atherosclerotic burden was quantified using a calcium scoring method. RESULTS: The patients with <1 caries surfaces/tooth had a lower atherosclerotic burden (0.13±0.61 mL) than patients with ≥1 caries surfaces/tooth. The atherosclerotic burden was greater in patients with a higher number of lesions with pulpal involvement and more teeth with chronic apical periodontitis. In the logistical regression models, age (Wald 49.3), number of caries per tooth (Wald 26.4), periodontitis (Wald 8.6), and male gender (Wald 11) were found to be independent risk factors for atherosclerosis. In the linear regression analyses, age and the number of decayed surfaces per tooth were identified as influencing factors associated with a higher atherosclerotic burden, and the number of restorations per tooth was associated with a lower atherosclerotic burden. CONCLUSION: Dental caries, pulpal caries, and chronic apical periodontitis are associated positively, while restorations are associated inversely, with aortic atherosclerotic burden. Prospective studies are required to confirm these observations and answer the question of possible causality.

Non-surgical periodontal therapy influences salivary melatonin levels

ObjectivesMelatonin is a hormone, which is involved in the control of the circadian rhythm, but also acts as an antioxidant and immune modulator. Previous studies reported decreased salivary and serum melatonin levels in periodontitis. This prospective cohort trial assessed the effect of non-surgical periodontal therapy on melatonin levels.MethodsSalivary and serum samples of 60 participants (30 patients suffering from a severe generalized form of periodontitis, 30 healthy controls) were collected at baseline and 19 samples of periodontitis patients after treatment. Salivary and serum melatonin levels were determined by a commercially available ELISA kit and serum C-reactive protein (CRP) by a routine laboratory test.ResultsAt baseline, periodontitis patients showed significantly increased serum CRP values and significantly decreased salivary melatonin levels compared to the control group. Clinical periodontal parameters significantly correlated with salivary melatonin levels and serum CRP. Periodontal therapy resulted in a recovery of the decreased salivary melatonin levels and a negative correlation was detected for the changes of salivary melatonin and the inflammatory parameter bleeding on probing. Serum melatonin levels showed no significant differences.ConclusionsSalivary melatonin levels recovered after periodontal therapy and correlated with a decrease of local periodontal inflammation. This may imply the local involvement of melatonin in the pathogenesis of periodontitis due to its antioxidant abilities. However, the exact role of melatonin in periodontal disease remains to be investigated in future trials.Clinical relevanceThe present results suggest salivary melatonin as a risk indicator for the severity of periodontal disease.

Decreased phosphorylation of platelet vasodilator-stimulated phosphoprotein in periodontitis – a role of periodontal pathogens

INTRODUCTION Epidemiological studies indicate an association between periodontitis and cardiovascular disease, but the underlying mechanisms are poorly understood. Vasodilator-stimulated phosphoprotein (VASP) in its phosphorylated form represents a regulator of platelet function and an indicator for the sensitivity of platelets towards physiologically relevant antagonists of platelet function. As platelets and their activation state play a central role in the development of cardiovascular disease, this study aimed to investigate the influence of periodontal disease and periodontal pathogens on intraplatelet VASP-phosphorylation and platelet function. MATERIAL AND METHODS Besides several markers of platelet activation, basal and PGE(1) induced intracellular VASP-phosphorylation were determined in platelets of periodontitis patients (n = 26) and healthy donors (n = 19). Furthermore, platelets from healthy donors were incubated with distinct periodontal pathogens and basal and PGE(1) induced VASP-phosphorylation was determined. RESULTS Compared to controls, platelets of periodontitis patients showed a significant decrease in basal and PGE(1) induced VASP-phosphorylation. VASP-phosphorylation in platelets from periodontitis patients positive for Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis or Tannerella forsythia was significantly decreased compared to patients that were negative for these bacteria. Furthermore, VASP-phosphorylation in platelets isolated from healthy donors was affected by incubation with these periodontal pathogens. CONCLUSIONS Our results provide evidence that periodontitis interferes with VASP-phosphorylation in human platelets, presumably as a consequence of a direct effect of periodontitis-associated bacteria. Decreased basal and PGE(1) induced VASP-phosphorylation might represent a mechanism responsible for enhanced platelet activation in periodontitis.

Morphometric characteristics of cortical and trabecular bone in atrophic edentulous mandibles

OBJECTIVES Adaptations of the alveolar ridge after tooth loss have been well described. However, studies on the morphometric characteristics of cortical bone are rare; hence, this study of human atrophic edentulous mandibles was undertaken. MATERIAL AND METHODS Total cortical area, porosity, and thickness, and the percentage of cortical area in the complete mandibular area as well as in an area (height, 10 mm) starting at the most caudal point of the trabecular compartment and extending in the coronal direction were determined in 185 thin ground sections of edentulous mandibles (incisor region, 49; premolar region, 76; molar region, 60; 95 from females and 90 from males; mean age, 78.2 years, SD ± 7.8 years; Caucasian donors; cause of death: cardiovascular disease). Further, mandibular height and width and degree of residual ridge resorption (RRR) were recorded. RESULTS The percentage of cortical area in the complete mandibular area increased with increasing RRR. Yet, evaluation of the 10-mm caudal portion corresponding to the basal part of the mandibular body did not confirm these changes in cortical bone. Cortical porosity and thickness decreased from the mesial to the distal region. Cortical porosity was unaffected by RRR, while cortical thickness increased, mainly at lingual aspects. CONCLUSIONS In conclusion, cortical bone remained stable in different degrees of RRR except for some modulations in the lingual aspects. Changes in the relative composition between cortical and trabecular bone are due to loss of height and total area, mainly at expense of trabecular bone area, but not to adaptations of the cortical bone.

Relative Composition of Fibrous Connective and Fatty/Glandular Tissue in Connective Tissue Grafts Depends on the Harvesting Technique but not the Donor Site of the Hard Palate

BACKGROUND Whether the composition of palatal connective tissue grafts (CTGs) varies depending on donor site or harvesting technique in terms of relative amounts of fibrous connective tissue (CT) and fatty/glandular tissue (FGT) is currently unknown and is histologically assessed in the present study. METHODS In 10 fresh human cadavers, tissue samples were harvested in the anterior and posterior palate and in areas close to (marginal) and distant from (apical) the mucosal margin. Mucosal thickness, lamina propria thickness (defined as the extent of subepithelial portion of the biopsy containing ≤25% or ≤50% FGT), and proportions of CT and FGT were semi-automatically estimated for the entire mucosa and for CTGs virtually harvested by split-flap (SF) preparation minimum 1 mm deep or after deepithelialization (DE). RESULTS Palatal mucosal thickness, ranging from 2.35 to 6.89 mm, and histologic composition showed high interindividual variability. Lamina propria thickness (P >0.21) and proportions of CT (P = 0.48) and FGT (P = 0.15) did not differ significantly among the donor sites (anterior, posterior, marginal, apical). However, thicker palatal tissue was associated with higher FGT content (P <0.01) and thinner lamina propria (P ≤0.03). Independent of the donor site, DE-harvested CTG contained a significantly higher proportion of CT and a lower proportion of FGT than an SF-harvested CTG (P <0.04). CONCLUSION Despite high interindividual variability in terms of relative tissue composition in the hard palate, DE-harvested CTG contains much larger amounts of CT and much lower amounts of FGT than SF-harvested CTG, irrespective of the harvesting site.