Thomas Beikler

Gene expression in periodontal tissues following treatment

BackgroundIn periodontitis, treatment aimed at controlling the periodontal biofilm infection results in a resolution of the clinical and histological signs of inflammation. Although the cell types found in periodontal tissues following treatment have been well described, information on gene expression is limited to few candidate genes. Therefore, the aim of the study was to determine the expression profiles of immune and inflammatory genes in periodontal tissues from sites with severe chronic periodontitis following periodontal therapy in order to identify genes involved in tissue homeostasis.Gingival biopsies from 12 patients with severe chronic periodontitis were taken six to eight weeks following non-surgical periodontal therapy, and from 11 healthy controls. As internal standard, RNA of an immortalized human keratinocyte line (HaCaT) was used. Total RNA was subjected to gene expression profiling using a commercially available microarray system focusing on inflammation-related genes. Post-hoc confirmation of selected genes was done by Realtime-PCR.ResultsOut of the 136 genes analyzed, the 5% most strongly expressed genes compared to healthy controls were Interleukin-12A (IL-12A), Versican (CSPG-2), Matrixmetalloproteinase-1 (MMP-1), Down syndrome critical region protein-1 (DSCR-1), Macrophage inflammatory protein-2β (Cxcl-3), Inhibitor of apoptosis protein-1 (BIRC-1), Cluster of differentiation antigen 38 (CD38), Regulator of G-protein signalling-1 (RGS-1), and Finkel-Biskis-Jinkins murine osteosarcoma virus oncogene (C-FOS); the 5% least strongly expressed genes were Receptor-interacting Serine/Threonine Kinase-2 (RIP-2), Complement component 3 (C3), Prostaglandin-endoperoxide synthase-2 (COX-2), Interleukin-8 (IL-8), Endothelin-1 (EDN-1), Plasminogen activator inhibitor type-2 (PAI-2), Matrix-metalloproteinase-14 (MMP-14), and Interferon regulating factor-7 (IRF-7).ConclusionGene expression profiles found in periodontal tissues following therapy indicate activation of pathways that regulate tissue damage and repair.

Polyphenols from Myrothamnus flabellifolia Welw. inhibit in vitro adhesion of Porphyromonas gingivalis and exert anti‐inflammatory cytoprotective effects in KB cells

AIMnIdentification of anti-adhesive plant extracts against cell surface binding of Porphyromonas gingivalis and underlying mechanisms; investigation of potential cytoprotective effects of anti-adhesive extract on KB cells.nnnMATERIALS AND METHODSnPolyphenol-enriched extract, fully characterized concerning flavan-3-ols and oligomeric proanthocyanidins, from Myrothamnus flabellifolia (MF), traditionally used for periodontitis, was tested for inhibition of P. gingivalis-mediated adhesion to KB cells by flow cytometry, for influence on gingipain activity (protease assay), haemagglutination and by microarray analysis for effects on bacterial transcriptome. The influence of MF on P. gingivalis-induced cytokine gene expression was monitored by RT-PCR and IL-6 titres by ELISA.nnnRESULTSnMF (100 μg/ml) reduced P. gingivalis adhesion/invasion about 50% by interacting with bacterial OMPs. As shown by RT-PCR, fimbrillin and Arg-gingipain encoding genes were up-regulated by MF. On the protein level, inhibition (70%) of Arg-gingipain activity was observed, while the corresponding Lys-gingipain was hardly influenced. MF also inhibited haemagglutination. While exposure to P. gingivalis resulted in an increased expression of inflammation-related genes in KB cells, pre-treatment of KB cells with MF evoked cytoprotective effects concerning IL-1β, IL-6, IL-8 and TNF-α gene expression as well as IL-6 release rates. Compounds from the plant extract belonging to the class of proanthocyanidins were shown to be responsible for the observed effects and were characterized for their respective structural features.nnnCONCLUSIONSnWhile being cytoprotective, MF exerts anti-adhesive effects against P. gingivalis. Thus, MF may be useful for the prevention of P. gingivalis-associated periodontal diseases.

Prevalence of Molar–Incisor–Hypomineralisation among school children in four German cities

BACKGROUNDnA wide range for the prevalence of Molar-Incisor-Hypomineralisation (MIH) has been found in regional studies.nnnAIMnThe aim of this study was to determine the prevalence of MIH in Germany and to compare the findings with other studies.nnnDESIGNnIn the compulsory dental school examination, the first permanent molars, permanent incisors, and second primary molars were examined according to EAPD criteria in 2395 children (8.1 ± 0.8 years) in four regions in Germany for the presence of MIH. Examinations were performed by five calibrated examiners (κ = 0.9) on clean teeth after toothbrushing.nnnRESULTSnThe prevalence of MIH at the four regions differed considerably (4.3-14.6%) with a mean prevalence of 10.1%. The DMFT/dmft was generally low, but children with MIH exhibited statistically significant higher caries values. A total of 12.0% of the children with MIH also had at least one affected primary molar, which resulted in a statistically significant correlation between primary and permanent teeth. Most of the affected teeth had demarcated opacities, but more than half of the affected children showed at least one tooth with severe MIH.nnnCONCLUSIONSnMolar-Incisor-Hypomineralisation is a prevalent finding in German school children. The prevalence varies highly in different regions, and the high rate of severe forms has clinically relevant implications.

Efficacy and safety of adjunctive local moxifloxacin delivery in the treatment of periodontitis.

BACKGROUNDnMoxifloxacin exerts excellent antibacterial activity against most putative periodontal pathogens and has been shown to kill bacteria in biofilm and host cells.nnnMETHODSnPatients with chronic periodontitis were randomly assigned to receive a single subgingival application of a 0.125%, 0.4%, or 1.25% moxifloxacin gel or placebo gel immediately after full-mouth scaling and root planing (SRP). Clinical efficacy measurements were assessed in sites with baseline probing depth (PD) of ≥5.4 mm at 6 weeks and 3 months and any adverse events were determined. In addition, putative periodontal pathogens and resistance of subgingival bacteria against moxifloxacin were assessed.nnnRESULTSnData of 57 patients were included in the statistical analysis. In all treatment groups, the PD decreased from baseline to 3 months, with the greatest reduction seen in patients treated with moxifloxacin 0.4% (1.5 ± 0.6 mm; P = 0.023 compared to placebo), followed by patients receiving moxifloxacin 1.25% (1.2 ± 0.4), moxifloxacin 0.125% (1.1 ± 1.1), and placebo (1.0 ± 0.6). No linear trend for PD reduction with increasing moxifloxacin concentrations was found. Porphyromonas gingivalis showed the greatest reduction in prevalence among the assessed pathogens, without any significant intergroup differences. No correlation or systematic relationship between adverse events, including bacterial resistance against moxifloxacin, and the investigational gels was found.nnnCONCLUSIONSnIn periodontal pockets with PD of ≥5.4 mm, a single subgingival administration of a 0.4% moxifloxacin gel as an adjunct to SRP may result in additional PD reduction compared to SRP alone. In addition, the investigated moxifloxacin gels seem to be safe.

EAO consensus conference: economic evaluation of implant-supported prostheses

OBJECTIVEnThere are various alternatives for the management of oral conditions that may lead to or already have lead to partial or full edentulism. Economic evaluations measure the efficiency of alternative healthcare interventions and provide useful information for decision-making and the allocation of scarce resources.nnnMATERIAL AND METHODSnThe current English literature dealing with cost-effectiveness of dental implant therapy versus different alternative treatment modalities, that is, complete and fixed partial dentures, root canal, and periodontal treatment, has been included in this narrative review. Due to the high heterogeneity within the literature, a meta-analysis could not be conducted.nnnRESULTSnThe available evidence from economic evaluations indicated that for the treatment of central incisors with irreversible pulpitis and coronal lesions, root canal treatments were most cost-effective initial treatment options. When initial root canal treatments failed, orthograde retreatments were most cost-effective. When root canal retreatments failed, extractions and replacement with single implant-supported crowns were more cost-effective compared to fixed or removable partial dentures. In the treatment of periodontitis in molars with Class I furcation invasion, non-surgical periodontal therapy was more effective and costed less than implant-supported single crowns. For the replacement of single missing teeth, two evaluations indicated that implant-supported single crowns provided better outcomes in terms of greater quality-adjusted tooth years or survival rates at lower costs compared to fixed partial prostheses. Another economic evaluation found that implant-supported crowns costed more, but provided greater survival rates compared to fixed partial dentures. For the restoration of edentulous mandibles, two evaluations indicated that overdentures retained by two or four implants improved oral health-related quality of life outcomes, but costed more than complete dentures.nnnCONCLUSIONSnTo better assess the efficiency of implant-supported prostheses in various clinical conditions, more economic evaluations are needed that follow well-established methodologies in health economics.

Towards microbiome transplant as a therapy for periodontitis: an exploratory study of periodontitis microbial signature contrasted by oral health, caries and edentulism

BackgroundConventional periodontal therapy aims at controlling supra- and subgingival biofilms. Although periodontal therapy was shown to improve periodontal health, it does not completely arrest the disease. Almost all subjects compliant with periodontal maintenance continue to experience progressive clinical attachment loss and a fraction of them loses teeth. An oral microbial transplant may be a new alternative for treating periodontitis (inspired by fecal transplant). First, it must be established that microbiomes of oral health and periodontitis are distinct. In that case, the health-associated microbiome could be introduced into the oral cavity of periodontitis patients. This relates to the goals of our study: (i) to assess if microbial communities of the entire oral cavity of subjects with periodontitis were different from or oral health contrasted by microbiotas of caries and edentulism patients; (ii) to test in vitro if safe concentration of sodium hypochlorite could be used for initial eradication of the original oral microbiota followed by a safe neutralization of the hypochlorite prior transplantation.MethodsSixteen systemically healthy white adults with clinical signs of one of the following oral conditions were enrolled: periodontitis, established caries, edentulism, and oral health. Oral biofilm samples were collected from sub- and supra-gingival sites, and oral mucosae. DNA was extracted and 16S rRNA genes were amplified. Amplicons from the same patient were pooled, sequenced and quantified. Volunteer’s oral plaque was treated with saline, 16xa0mM NaOCl and NaOCl neutralized by ascorbate buffer followed by plating on blood agar.ResultsOrdination plots of rRNA gene abundances revealed distinct groupings for the oral microbiomes of subjects with periodontitis, edentulism, or oral health. The oral microbiome in subjects with periodontitis showed the greatest diversity harboring 29 bacterial species at significantly higher abundance compared to subjects with the other assessed conditions. Healthy subjects had significantly higher abundance in 10 microbial species compared to the other conditions. NaOCl showed strong antimicrobial properties; nontoxic ascorbate was capable of neutralizing the hypochlorite.ConclusionsDistinct oral microbial signatures were found in subjects with periodontitis, edentulism, or oral health. This finding opens up a potential for a new therapy, whereby a health-related entire oral microbial community would be transplanted to the diseased patient.

Irreversible Inflammation is Associated with Decreased Levels of the α1-, β1-, and α2-Subunits of sGC in Human Odontoblasts

The nitric oxide (NO) receptor enzyme soluble guanylate cyclase (sGC) contains one prosthetic heme group as an αβ heterodimer, and two heterodimer isoforms (α1β1, α2β1) were characterized to have enzyme activity. To test the irreversible inflammation-dependent regulation of sGC in odontoblasts, we incubated decalcified frozen sections of healthy and inflamed human third molars with antibodies against β-actin, nitrotyrosine, inducible nitric oxide synthase (iNOS), α1-, β1-, and α2-subunits of sGC and analyzed them at protein levels by quantitative immunohistochemistry. The irreversible inflammation induced an increase in the signal intensities for nitrotyrosine and iNOS and a decrease for the α1-, β1-, and α2-subunits of sGC in odontoblasts. Inflammatory mediators, reactive oxygen, and nitrogen species may impair the expression of the α1-, β1-, and α2-subunits in odontoblasts. The decrease of sGC at the protein level in inflamed odontoblasts is compatible with a critical role for sGC to mediate biological effects of NO in health.

Bacterial viability on surface-modified resin-based dental restorative materials

UNLABELLEDnThe purpose of the present investigation was to investigate the viability of early colonizers on the surfaces of resin-based dental restorative materials modified with low-surface tension active agents in comparison with the unmodified material. A novel polymeric sorption material, loaded with two low-surface tension γ(L) active agents (hydroxyfunctional polydimethylsiloxane and polydimethylsiloxane) or a polymerizable active agent (silicone polyether acrylate), was used to modify commonly formulated experimental dental resin composites. The non-modified resin was used as the standard (ST). The viability of Actinomyces naeslundii, Actinomyces viscosus, Streptococcus mitis, Streptococcus oralis, and Streptococcus sanguinis on water-stored, polished, and human saliva pellicle-coated specimens was determined using a fluorescence microscope after 8 and 24h. Total, vital, and non-vital cells were calculated from the microscopic images by counting pixels per colour. Means, standard deviations, univariate ANOVA and multiple comparisons with post hoc Scheffés tests were calculated. t-Test was done to compare 8-h and 24-h bacteria counts. For all tests p<0.05 was chosen.nnnNULL HYPOTHESISnthe test materials and the standard did not differ either in the total bacterial counts or in the respective bacteriums viability after 8 or 24h. The test materials modified with the silicone polyether acrylate showed lower total bacteria count after 8 or 24h than ST. But all test materials had significantly fewer vital cells after 8 or 24h compared to ST. The contact angle did not influence bacterial adhesion, but low total SFE and a low polar term of SFE resulted in fewer bacteria. The materials chemistry also affected the total and vital cell counts. Different bacteria viabilities needed to be explored to obtain relevant information regarding bacterial adhesion on dental composite resins. The novel sorption material loaded with low γ(L) active agents or with a low γ(L) polymerizable silicone polyether acrylate used to modify the chemistry of the test materials was appropriate to reduce bacterial adhesion or cell viability, respectively.

Extract from Rumex acetosa L. for Prophylaxis of Periodontitis: Inhibition of Bacterial In Vitro Adhesion and of Gingipains of Porphyromonas gingivalis by Epicatechin-3-O-(4β→8)-Epicatechin-3-O-Gallate (Procyanidin-B2-Di-Gallate)

Background The aerial parts of Rumex acetosa L. have been used in traditional European medicine for inflammatory diseases of the mouth epithelial tissue. The following study aimed to investigate the influence of a proanthocyanidin-enriched extract from R. acetosa extract against the adhesion of Porphyromonas gingivalis (P. gingivalis), a pathogen strongly involved in chronic and aggressive periodontitis. A further goal was to define the bioactive lead structures responsible for a potential antiadhesive activity and to characterize the underlying molecular mechanisms of the antiadhesive effects. Methodology An extract of R. acetosa (RA1) with a defined mixture of flavan-3-ols, oligomeric proanthocyanidins and flavonoids, was used. Its impact on P. gingivalis adhesion to KB cells was studied by flow cytometry, confocal laser scanning microscopy and in situ adhesion assay using murine buccal tissue. RA1 and its compounds 1 to 15 were further investigated for additional effects on gingipain activity, hemagglutination and gene expression by RT-PCR. Principal Findings RA1 (5 to 15 μg/mL) reduced P. gingivalis adhesion in a dose-dependent manner to about 90%. Galloylated proanthocyanidins were confirmed to be responsible for this antiadhesive effect with epicatechin-3-O-gallate-(4β,8)-epicatechin-3’-O-gallate (syn. procyanidin B2-di-gallate) being the lead compound. Ungalloylated flavan-3-ols and oligomeric proanthocyanidins were inactive. RA1 and the galloylated proanthocyanidins strongly interact with the bacterial virulence factor Arg-gingipain, while the corresponding Lys-gingipain was hardly influenced. RA1 inhibited also hemagglutination. In silico docking studies indicated that epicatechin-3-O-gallate-(4β,8)-epicatechin-3’-O-gallate interacts with the active side of Arg-gingipain and hemaglutinin from P. gingivalis; the galloylation of the molecule seems to be responsible for fixation of the ligand to the protein. In conclusion, the proanthocyanidin-enriched extract RA1 and its main active constituent procyanidin B2-di-gallate protect cells from P. gingivalis infection by inhibiting bacterial adhesion to the host cell. RA1 and procyanidin B2-di-gallate appear to be promising candidates for future cytoprotective preparations for oral mouth care products.

Severity of MIH findings at tooth surface level among German school children

AimThis study was to investigate the distribution and clinical characteristics of teeth diagnosed with MIH at surface and defect type level in a cohort of German children.MethodsThe study cohort included 242 children diagnosed with MIH which had been recorded during the compulsory dental school examinations of 20 German primary schools. The subjects had been enrolled by cluster sampling. All children attended the second to fourth grade (age 7–10xa0years, mean 8.1xa0±xa00.8). The children were examined by five calibrated examiners (kappaxa0=xa00.9) after tooth brushing. The recording comprised teeth, surfaces, type and severity of MIH defects and was conducted using a portable light, mirrors and cotton rolls. MIH was registered according to the EAPD criteria. Defects <1xa0mm were not recorded. Statistical analysis included descriptive statistics and Spearman’s correlation.ResultsMost affected teeth were first permanent molars (71.4xa0%) followed by the maxillary central incisors (15.6xa0%). The most common defects were demarcated opacities (82.2xa0%), while the remaining 17.8xa0% of the affected teeth exhibited severe enamel defects. The most frequently affected surface in molars was the occlusal surface (72.4xa0%); in incisors, it was the buccal surface (73.5xa0%). There were no atypical restorations in the affected incisors. Different types of MIH defects at various surfaces of the same tooth were common. The number of affected tooth surfaces was positively correlated with the severity of MIH at child (pxa0<xa00.001).ConclusionsThe study demonstrates severe enamel defects involving in almost one-fifth of all MIH teeth. The knowledge of the intra-oral distribution and severity of MIH findings at the enamel surface level is important for assessing the treatment needs.