Publications by authors named "Karim Fawzy El-Sayed"

40 Publications

Ultra-short versus standard-length dental implants in conjunction with osteotome-mediated sinus floor elevation: A randomized controlled clinical trial.

Clin Implant Dent Relat Res 2021 Jun 8. Epub 2021 Jun 8.

Faculty of Dentistry, Department of Oral Medicine and Periodontology, Cairo University, Cairo, Egypt.

Background: The ability to restore missing teeth with dental implants is dictated by the available bone and by the presence of anatomical structures. The potential to insert ultrashort implants avoids additional surgical procedures and its inherent complications. The last European Association of Dental Implantologists consensus in 2016 defined ultrashort implants and standard-length dental implants as <6 and >8 mm, respectively.

Purpose: The present study aimed to investigate whether single standing ultrashort dental implants (US) could provide a viable therapeutic alternative to osteotome mediated sinus floor elevation in combination with standard-length dental implants (SL) 10 mm in posterior maxillary rehabilitation with reduced bone height.

Materials And Methods: The study was conducted as a prospective parallel group controlled clinical trial with a 12 month follow-up, where 48 implants were randomized into two groups; US-group (5.5 mm) and SL-group (10 mm) implants placed with osteotome-mediated sinus floor elevation. Crestal bone loss (CBL) was defined as the study's primary outcome, while implant survival, buccal bone thickness, implant stability, probing depth, gingival recession, and adverse effects were assessed as secondary outcomes.

Results: Mesial CBL was 1.13 ± 0.52 mm in SL- and 0.72 ± 0.52 mm in US-group (P = .021), while distal CBL was 1.44 ± 0.72 mm in SL- and 0.91 ± 0.69 mm in US-group at 12 months (P = .0179). Regarding implant stability, probing depth, and gingival recession there was no statistically significant difference between the two groups. Regarding implants' survival, three implants were lost in the US-while only one implant was lost in the SL-group (P = .6085; Fisher's exact test). Nevertheless, the ultrashort implants were associated with a tripling of the failure rate and uncertainty where the true failure rate is uncertain (relative risk 3.0; confidence interval 0.3-26.8).

Conclusions: Within the current trial's limitations, US-appear appear promising as they are associated less postoperative discomfort, minimal invasiveness and less CBL. However, larger sample size is required to determine whether the ultrashort have an acceptable survival rate.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/cid.12995DOI Listing
June 2021

Mesenchymal Stem/Progenitor Cells: The Prospect of Human Clinical Translation.

Stem Cells Int 2020 11;2020:8837654. Epub 2020 Aug 11.

Stem Cells and Tissue Engineering Research Group, Faculty of Dentistry, Cairo University, Cairo, Egypt.

Mesenchymal stem/progenitor cells (MSCs) are key players in regenerative medicine, relying principally on their differentiation/regeneration potential, immunomodulatory properties, paracrine effects, and potent homing ability with minimal if any ethical concerns. Even though multiple preclinical and clinical studies have demonstrated remarkable properties for MSCs, the clinical applicability of MSC-based therapies is still questionable. Several challenges exist that critically hinder a successful clinical translation of MSC-based therapies, including but not limited to heterogeneity of their populations, variability in their quality and quantity, donor-related factors, discrepancies in protocols for isolation, in vitro expansion and premodification, and variability in methods of cell delivery, dosing, and cell homing. Alterations of MSC viability, proliferation, properties, and/or function are also affected by various drugs and chemicals. Moreover, significant safety concerns exist due to possible teratogenic/neoplastic potential and transmission of infectious diseases. Through the current review, we aim to highlight the major challenges facing MSCs' human clinical translation and shed light on the undergoing strategies to overcome them.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2020/8837654DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8063852PMC
August 2020

Clinical and radiographic effects of ascorbic acid-augmented platelet-rich fibrin versus platelet-rich fibrin alone in intra-osseous defects of stage-III periodontitis patients: a randomized controlled clinical trial.

Clin Oral Investig 2021 Apr 12. Epub 2021 Apr 12.

Oral Medicine and Periodontology Department, Faculty of Dentistry, Cairo University, Al Saraya Str. 11, Manial, Cairo, Egypt.

Aim: To assess platelet-rich fibrin (PRF) with ascorbic acid (AA) versus PRF in intra-osseous defects of stage-III periodontitis patients.

Methodology: Twenty stage-III/grade C periodontitis patients, with ≥ 3 mm intra-osseous defects, were randomized into test (open flap debridement (OFD)+AA/PRF; n = 10) and control (OFD+PRF; n = 10). Clinical attachment level (CAL; primary outcome), probing pocket depth (PPD), gingival recession depth (RD), full-mouth bleeding scores (FMBS), full-mouth plaque scores (FMPS), radiographic linear defect depth (RLDD) and radiographic defect bone density (RDBD) (secondary-outcomes) were examined at baseline, 3 and 6 months post-surgically.

Results: OFD+AA/PRF and OFD+PRF demonstrated significant intragroup CAL gain and PPD reduction at 3 and 6 months (p < 0.001). OFD+AA/PRF and OFD+PRF showed no differences regarding FMBS or FMPS (p > 0.05). OFD+AA/PRF demonstrated significant RD reduction of 0.90 ± 0.50 mm and 0.80 ± 0.71 mm at 3 and 6 months, while OFD+PRF showed RD reduction of 0.10 ± 0.77 mm at 3 months, with an RD-increase of 0.20 ± 0.82 mm at 6 months (p < 0.05). OFD+AA/PRF and OFD+PRF demonstrated significant RLDD reduction (2.29 ± 0.61 mm and 1.63 ± 0.46 mm; p < 0.05) and RDBD-increase (14.61 ± 5.39% and 12.58 ± 5.03%; p > 0.05). Stepwise linear regression analysis showed that baseline RLDD and FMBS at 6 months were significant predictors of CAL reduction (p < 0.001).

Conclusions: OFD+PRF with/without AA significantly improved periodontal parameters 6 months post-surgically. Augmenting PRF with AA additionally enhanced gingival tissue gain and radiographic defect fill.

Clinical Relevance: PRF, with or without AA, could significantly improve periodontal parameters. Supplementing PRF with AA could additionally augment radiographic linear defect fill and reduce gingival recession depth.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00784-021-03929-1DOI Listing
April 2021

Alveolar ridge preservation using autogenous whole-tooth versus demineralized dentin grafts: A randomized controlled clinical trial.

Clin Oral Implants Res 2021 May 1;32(5):539-548. Epub 2021 Mar 1.

Oral Medicine and Periodontology Department, Faculty of Dentistry, Cairo University, Cairo, Egypt.

Objective: The objective of this randomized controlled trial was to evaluate the radiographic changes and histologic healing following alveolar ridge preservation (ARP) using autogenous whole tooth (AWTG), test group, versus autogenous demineralized dentin graft (ADDG), control group.

Material And Methods: Twenty non-molar teeth indicated for extraction were randomized into two groups (n = 10/group). Extracted teeth were prepared into AWTG or ADDG (0.6N HCl; 30 min), inserted into extraction sockets and covered by collagen membranes. Cone-beam computed tomography (CBCT) scans at baseline and six months were compared to assess ridge-dimensional changes. At six months, bone biopsies of engrafted sites were harvested and analyzed histomorphometrically.

Results: All sites healed uneventfully. Reduction was 0.85 ± 0.38 mm and 1.02 ± 0.45 mm in ridge width, 0.61 ± 0.20 mm and 0.72 ± 0.27 mm in buccal and 0.66 ± 0.31 mm and 0.56 ± 0.24 mm in lingual ridge height for the AWTG and ADDG group, respectively (p > .05). Histologically, no inflammatory reactions were noticeable and all samples showed new bone formation. Qualitatively, graft-bone amalgamations were more pronounced in ADDG samples. Histomorphometrically, new bone, graft remnants and soft tissue occupied 37.55% ± 8.94%, 17.05% ± 5.58% and 45.4% ± 4.06% of the areas in the AWTG group and 48.4% ± 11.56%, 11.45% ± 4.13% and 40.15% ± 7.73% in the ADDG group of the examined areas, respectively (p > .05).

Conclusions: AWTG and ADDG are similarly effective in ARP. Yet, histologically ADDG seems to demonstrate better graft remodeling, integration and osteoinductive properties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/clr.13722DOI Listing
May 2021

Hydrogels and Dentin-Pulp Complex Regeneration: From the Benchtop to Clinical Translation.

Polymers (Basel) 2020 Dec 9;12(12). Epub 2020 Dec 9.

Stem Cells and Tissue Engineering Research Group, Faculty of Dentistry, Cairo University, Cairo 11562, Egypt.

Dentin-pulp complex is a term which refers to the dental pulp (DP) surrounded by dentin along its peripheries. Dentin and dental pulp are highly specialized tissues, which can be affected by various insults, primarily by dental caries. Regeneration of the dentin-pulp complex is of paramount importance to regain tooth vitality. The regenerative endodontic procedure (REP) is a relatively current approach, which aims to regenerate the dentin-pulp complex through stimulating the differentiation of resident or transplanted stem/progenitor cells. Hydrogel-based scaffolds are a unique category of three dimensional polymeric networks with high water content. They are hydrophilic, biocompatible, with tunable degradation patterns and mechanical properties, in addition to the ability to be loaded with various bioactive molecules. Furthermore, hydrogels have a considerable degree of flexibility and elasticity, mimicking the cell extracellular matrix (ECM), particularly that of the DP. The current review presents how for dentin-pulp complex regeneration, the application of injectable hydrogels combined with stem/progenitor cells could represent a promising approach. According to the source of the polymeric chain forming the hydrogel, they can be classified into natural, synthetic or hybrid hydrogels, combining natural and synthetic ones. Natural polymers are bioactive, highly biocompatible, and biodegradable by naturally occurring enzymes or via hydrolysis. On the other hand, synthetic polymers offer tunable mechanical properties, thermostability and durability as compared to natural hydrogels. Hybrid hydrogels combine the benefits of synthetic and natural polymers. Hydrogels can be biofunctionalized with cell-binding sequences as arginine-glycine-aspartic acid (RGD), can be used for local delivery of bioactive molecules and cellularized with stem cells for dentin-pulp regeneration. Formulating a hydrogel scaffold material fulfilling the required criteria in regenerative endodontics is still an area of active research, which shows promising potential for replacing conventional endodontic treatments in the near future.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/polym12122935DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7763835PMC
December 2020

Ascorbic Acid, Inflammatory Cytokines (IL-1/TNF-/IFN-), or Their Combination's Effect on Stemness, Proliferation, and Differentiation of Gingival Mesenchymal Stem/Progenitor Cells.

Stem Cells Int 2020 17;2020:8897138. Epub 2020 Aug 17.

Clinic for Conservative Dentistry and Periodontology, School of Dental Medicine, Christian Albrechts University, Kiel, Germany.

Objective: Ascorbic acid (AA) and controlled inflammatory stimuli are postulated to possess the ability to independently exert positive effects on a variety of proliferative, pluripotency, and differentiation attributes of gingival mesenchymal stem/progenitor cells (G-MSCs). The current study's objective was to explore and compare for the first time the impact of the major inflammatory cytokines (IL-1/TNF-/IFN-), AA, or their combination on multipotency/pluripotency, proliferative, and differentiation characteristics of G-MSCs.

Design: Human G-MSCs ( = 5) were isolated and cultured in basic medium (control group), in basic medium with major inflammatory cytokines; 1 ng/ml IL-1, 10 ng/ml TNF-, and 100 ng/ml IFN- (inflammatory group), in basic medium with 250 mol/l AA (AA group) and in inflammatory medium supplemented by AA (inflammatory/AA group). All media were renewed three times per week. In stimulated G-MSCs intracellular -catenin at 1 hour, pluripotency gene expression at 1, 3, and 5 days, as well as colony-forming units (CFUs) ability and cellular proliferation over 14 days were examined. Following a five-days stimulation in the designated groups, multilineage differentiation was assessed via qualitative and quantitative histochemistry as well as mRNA expression.

Results: -Catenin significantly decreased intracellularly in all experimental groups ( = 0.002, Friedman). AA group exhibited significantly higher cellular counts on days 3, 6, 7, and 13 ( < 0.05) and the highest CFUs at 14 days [median-CFUs (Q25/Q75); 40 (15/50), = 0.043]. Significantly higher Nanog expression was noted in AA group [median gene-copies/PGK1 (Q25/Q75); 0.0006 (0.0002/0.0007), < 0.01, Wilcoxon-signed-rank]. Significant multilineage differentiation abilities, especially into osteogenic and chondrogenic directions, were further evident in the AA group.

Conclusions: AA stimulation enhances G-MSCs' stemness, proliferation, and differentiation properties, effects which are associated with a Wnt/-catenin signaling pathway activation. Apart from initially boosting cellular metabolism as well as Sox2 and Oct4A pluripotency marker expression, inflammation appeared to attenuate these AA-induced positive effects. Current results reveal that for AA to exert its beneficial effects on G-MSCs' cellular attributes, it requires to act in an inflammation-free microenvironment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2020/8897138DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7448213PMC
August 2020

Toll-like Receptor Expression Profile of Human Stem/Progenitor Cells Form the Apical Papilla.

J Endod 2020 Aug 19. Epub 2020 Aug 19.

Clinic for Conservative Dentistry and Periodontology, School of Dental Medicine, Christian-Albrechts University, Kiel, Germany; Oral Medicine and Periodontology Department, Faculty of Oral and Dental Medicine, Cairo University, Cairo, Egypt. Electronic address:

Introduction: Stem/progenitor cells from the apical papilla (SCAPs) demonstrate remarkable regenerative and immunomodulatory properties. During their regenerative events, SCAPs, similar to other stem/progenitor cells, could interact with their local inflammatory microenvironment via their expressed toll-like receptors (TLRs). The present study aimed to describe for the first time the unique TLR expression profile of SCAPs.

Methods: Cells were isolated from the apical papilla of extracted wisdom teeth (n = 8), STRO-1 immunomagnetically sorted, and cultured to obtain single colony-forming units. The expression of CD14, 34, 45, 73, 90, and 105 were characterized on the SCAPs, and their multilineage differentiation potential was examined to prove their multipotent aptitude. After their incubation in basic or inflammatory medium (25 ng/mL interleukin 1 beta, 10 U/mL interferon gamma, 50 ng/mL tumor necrosis factor alpha, and 3 × 10 U/mL interferon alpha), a TLR expression profile for SCAPs under uninflamed as well as inflamed conditions was respectively generated.

Results: SCAPs demonstrated all predefined stem/progenitor cell characteristics. In basic medium, SCAPs expressed TLRs 1-10. The inflammatory microenvironment up-regulated the expression of TLR1, TLR2, TLR4, TLR5, TLR6, and TLR9 and down-regulated the expression of TLR3, TLR7, TLR8, and TLR10 in SCAPs under the inflamed condition.

Conclusions: The present study defines for the first time a distinctive TLR expression profile for SCAPs under uninflamed and inflamed conditions. This profile could greatly impact SCAP responsiveness to their inflammatory microenvironmental agents under regenerative conditions in vivo.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.joen.2020.08.017DOI Listing
August 2020

TLR3 ligation affects differentiation and stemness properties of gingival mesenchymal stem/progenitor cells.

J Clin Periodontol 2020 08 11;47(8):991-1005. Epub 2020 Jun 11.

Clinic for Conservative Dentistry and Periodontology, School of Dental Medicine, Christian-Albrecht's University, Kiel, Germany.

Aim: Toll-like receptors are key players in mesenchymal stem/progenitor cells' micro-environmental crosstalk, endorsing various biological reactions. For the first time, this study investigates the effects of TLR3-ligation on gingival mesenchymal stem/progenitor cells (G-MSCs) stemness and differentiation properties.

Material And Methods: G-MSCs (n = 5) were isolated, sorted using anti-STRO-1 antibodies,and sowed on culture dishes to generate colony-forming units (CFUs), and their stem/progenitor cells' features and TLR3 expression were characterized. Subsequently, TLR3 activation of G-MSCs via Poly (I:C) was done, followed by an analysis of the expression of pluripotency-related factors, mesenchymal stemness-associated surface markers, and the ability to form CFUs and multilineage differentiation, using qualitative and quantitative histochemistry and RT-PCR.

Results: G-MSCs demonstrated all predefined stem/progenitor cells' characteristics and TLR3 expression. TLR3-activated G-MSCs showed a significantly reduced ability to form CFUs and pluripotency transcriptional factors expression. Mesenchymal stem/progenitor cell-associated surface markers and multilinear differentiation potential were significantly higher following TLR3 ligation (p < .05, Wilcoxon signed rank test).

Conclusions: TLR3-mediated activation maintains the mesenchymal stem/progenitor cells phenotype and drives G-MSCs' differentiation and commitment, with a shift away from an undifferentiated pluripotent cellular phenotype. This distinctive modulation could influence potential therapeutic applications of G-MSCs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jcpe.13323DOI Listing
August 2020

Induced Pluripotent Stem Cells in Dental and Nondental Tissue Regeneration: A Review of an Unexploited Potential.

Stem Cells Int 2020 29;2020:1941629. Epub 2020 Mar 29.

Stem Cells and Tissue Engineering Research Group, Faculty of Dentistry, Cairo University, Cairo, Egypt.

Cell-based therapies currently represent the state of art for tissue regenerative treatment approaches for various diseases and disorders. Induced pluripotent stem cells (iPSCs), reprogrammed from adult somatic cells, using vectors carrying definite transcription factors, have manifested a breakthrough in regenerative medicine, relying on their pluripotent nature and ease of generation in large amounts from various dental and nondental tissues. In addition to their potential applications in regenerative medicine and dentistry, iPSCs can also be used in disease modeling and drug testing for personalized medicine. The current review discusses various techniques for the production of iPSC-derived osteogenic and odontogenic progenitors, the therapeutic applications of iPSCs, and their regenerative potential in vivo and in vitro. Through the present review, we aim to explore the potential applications of iPSCs in dental and nondental tissue regeneration and to highlight different protocols used for the generation of different tissues and cell lines from iPSCs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2020/1941629DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7146092PMC
March 2020

Tissue Engineering Approaches for Enamel, Dentin, and Pulp Regeneration: An Update.

Stem Cells Int 2020 25;2020:5734539. Epub 2020 Feb 25.

Stem Cell and Tissue Engineering Research Group, Faculty of Dentistry, Cairo University, Cairo, Egypt.

Stem/progenitor cells are undifferentiated cells characterized by their exclusive ability for self-renewal and multilineage differentiation potential. In recent years, researchers and investigations explored the prospect of employing stem/progenitor cell therapy in regenerative medicine, especially stem/progenitor cells originating from the oral tissues. In this context, the regeneration of the lost dental tissues including enamel, dentin, and the dental pulp are pivotal targets for stem/progenitor cell therapy. The present review elaborates on the different sources of stem/progenitor cells and their potential clinical applications to regenerate enamel, dentin, and the dental pulpal tissues.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2020/5734539DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7060883PMC
February 2020

Alvogyl and absorbable gelatin sponge as palatal wound dressings following epithelialized free gingival graft harvest: a randomized clinical trial.

Clin Oral Investig 2020 Apr 6;24(4):1517-1525. Epub 2020 Mar 6.

Oral Medicine and Periodontology Department, Faculty of Oral and Dental Medicine, Cairo University, Giza, Egypt.

Objectives: This randomized controlled trial compares for the first time effects of Alvogyl versus absorbable gelatin sponge as palatal wound dressings on postoperative pain, amount of analgesic consumption, post-surgical bleeding, and wound re-epithelization.

Materials And Methods: Following sample size calculation, 36 systemically healthy patients requiring palatal mucosal graft harvesting were randomized to receive Alvogyl (intervention group, 18 patients) or absorbable gelatin sponge (control group, 18 patients) palatal dressings. Patient-reported VAS pain scores over 2 weeks were defined as primary outcome. Post-surgical bleeding, number of analgesics consumed, and complete re-epithelialization of the palatal wound for up to 5 weeks were defined as secondary outcomes.

Results: Although significantly higher VAS pain scores were reported in the control as compared with the intervention group up to 12 days post-surgically (from (median [range]) 8.5 [2-10] to 1 [0-2] and from 6 [0-10] to 0 [0-2] respectively), with higher analgesics consumption (from 2 [1-3] to 1 [0-3] and from 1 [0-3] to 0 [0-2] tablets respectively), a multivariate regression analysis considering age, gender, graft width/length, tissue thickness, analgesics intake, and dressing type demonstrated no statistically significant effect of any factor, including dressing type on VAS pain scores. At 4 weeks, 22.2% of patients in the intervention group versus 11.1% in the control group demonstrated complete re-epithelization of their palatal engraftment site, before complete re-epithelization in both groups at 5 weeks. No post-surgical bleeding was reported with both dressings.

Conclusions: Within the study's limitations, results suggest Alvogyl as a practical palatal surgical dressing, comparable with absorbable gelatin sponge in cost, pain reduction, hemostasis, and re-epithelization properties.

Trial Registration: www.ClinicalTrials.gov Identifier: NCT03402321 CLINICAL RELEVANCE: Alvogyl could present a novel palatal wound dressing material, comparable with gelatin sponge.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00784-020-03254-zDOI Listing
April 2020

Dental Stem Cell-Derived Secretome/Conditioned Medium: The Future for Regenerative Therapeutic Applications.

Stem Cells Int 2020 31;2020:7593402. Epub 2020 Jan 31.

Stem cells and Tissue Engineering Research Group, Faculty of Dentistry, Cairo University, Cairo, Egypt.

Regenerative medicine literature has proposed mesenchymal stem/progenitor cell- (MSC-) mediated therapeutic approaches for their great potential in managing various diseases and tissue defects. Dental MSCs represent promising alternatives to nondental MSCs, owing to their ease of harvesting with minimally invasive procedures. Their mechanism of action has been attributed to their cell-to-cell contacts as well as to the paracrine effect of their secreted factors, namely, secretome. In this context, dental MSC-derived secretome/conditioned medium could represent a unique cell-free regenerative and therapeutic approach, with fascinating advantages over parent cells. This article reviews the application of different populations of dental MSC secretome/conditioned medium in in vitro and in vivo animal models, highlights their significant implementation in treating different tissue' diseases, and clarifies the significant bioactive molecules involved in their regenerative potential. The analysis of these recent studies clearly indicate that dental MSCs' secretome/conditioned medium could be effective in treating neural injuries, for dental tissue regeneration, in repairing bone defects, and in managing cardiovascular diseases, diabetes mellitus, hepatic regeneration, and skin injuries, through regulating anti-inflammatory, antiapoptotic, angiogenic, osteogenic, and neurogenic mediators.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2020/7593402DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7013327PMC
January 2020

The Dental Pulp Stem/Progenitor Cells-Mediated Inflammatory-Regenerative Axis.

Tissue Eng Part B Rev 2019 10 11;25(5):445-460. Epub 2019 Sep 11.

Clinic for Conservative Dentistry and Periodontology, School of Dental Medicine, Christian Albrechts University, Kiel, Germany.

Relying on their ease of isolation and remarkable tissue reparative/regenerative potential, dental pulp stem/progenitor cells (DPSCs) gained pronounced importance in the field of regenerative dentistry. Though inflammation is classically considered the reason for the damage of the dentin-pulpal complex, it continues to be an essential stage of any dentin-pulpal tissue repair or regeneration procedures. During their performance of a pulpal tissue repair or regeneration actions, DPSCs interact with their inflammatory microenvironment locally, possibly influencing their fate and the result of any DPSCs-mediated dentin-pulpal reparative/regenerative endeavor. Hence, this review aims at comprehensively elaborating on these complex interactions of DPSCs with their local pulpal inflammatory microenvironment, particularizing on the inflammatory aspects, affecting DPSCs' stemness, homing/migration, proliferation, differentiation as well as immunomodulation characteristics, and the potentially fundamental intracellular processes involved and their anticipated association with the noncanonical as well as canonical Wnt/β-Catenin intracellular signaling. Impact Statement This review particularizes on the current state of knowledge on the complex interrelation between dental pulp stem/progenitor cells and their pulpal inflammatory microenvironment; elaborates on inflammation aspects affecting their stemness, proliferation, migration/homing, differentiation and immunomodulation characteristics, and the fundamental intracellular processes involved and their anticipated association with the canonical and noncanonical Wnt pathways. All these aspects could significantly affect the dento-pulpal regenerative therapeutic approaches .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/ten.TEB.2019.0106DOI Listing
October 2019

Predictors for tooth loss in periodontitis patients: Systematic review and meta-analysis.

J Clin Periodontol 2019 07 28;46(7):699-712. Epub 2019 May 28.

Department of Operative and Preventive Dentistry, Charité University of Berlin, Berlin, Germany.

Aim: A range of predictors for tooth loss in periodontitis patients have been reported. We performed a systematic review and meta-analysis to assess the consistency and magnitude of any association between a total of 12 predictors and tooth loss.

Materials And Methods: Medline/Embase/Central were searched for longitudinal studies investigating the association between predictors and tooth loss in periodontitis patients. Random-effects meta-analysis was performed, and study quality assessed.

Results: Twenty studies (15,422 patients, mean follow-up: 12 years) were included. The mean annual tooth loss/patient was 0.12 (min./max: 0.01/0.36). Older patients (n = 8 studies; OR: 1.05, 95% CI: 1.03-1.08/year), non-compliant ones (n = 11; 1.51, 1.06-2.16), diabetics (n = 7; 1.80, 1.26-2.57), those with IL-1-polymorphism (n = 3; 1.80; 1.29-2.52) and smokers (n = 15; 1.98, 1.58-2.48) had a significantly higher risk of tooth loss. Teeth with bone loss (n = 3; 1.04, 1.03-1.05/%), high probing pocket depth (n = 6; 3.19, 1.70-5.98), mobility (n = 4; 3.71, 1.65-8.38) and molars (n = 4; 4.22, 2.12-8.39), especially with furcation involvement (n = 5; 2.68, 1.75-4.08) also showed higher risks. Gender (n = 16; 0.95, 0.86-1.05) and endodontic affection (n = 3; 3.62, 0.99-13.2) were not significantly associated with tooth loss.

Conclusions: Older, non-compliant, smoking or diabetic patients, and teeth with bone loss, high probing pocket depth, mobility, or molars, especially with furcation involvement showed higher risks of tooth loss.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jcpe.13118DOI Listing
July 2019

Retinol/inflammation affect stemness and differentiation potential of gingival stem/progenitor cells via Wnt/β-catenin.

J Periodontal Res 2019 Aug 4;54(4):413-423. Epub 2019 Mar 4.

Clinic for Conservative Dentistry and Periodontology, School of Dental Medicine, Christian Albrechts-University, Kiel, Germany.

Background And Objective: Inflammatory cytokines impact the course of periodontal disease, repair, and regeneration. Vitamin A and its metabolites are inflammation-modulatory biomolecules, affecting cellular pluripotency. The aim of this study was to investigate the effect of retinol and periodontal inflammatory cytokines (IL-1β/TNF-α/IFN-γ) on pluripotency and proliferative properties of gingival mesenchymal stem/progenitor cells (G-MSCs), for the first time.

Material And Methods: Human G-MSCs (n = 5) were STRO-1 immuno-magnetically sorted, characterized and expanded in basic medium (control group), in basic medium with IL-1β (1 ng/mL), TNF-α (10 ng/mL), and IFN-γ (100 ng/mL) (inflammatory group), in basic medium with retinol (20 μmol/L) (retinol group) and with retinol added to the inflammatory group (inflammatory/retinol group). β-catenin levels at 1 hour, cellular proliferation over 14 days, and colony-forming units (CFUs) at 14 days were investigated. Pluripotency gene expressions were examined at 1, 3, and 5 days via reverse transcription-polymerase chain reaction (RT-PCR). Multilineage differentiation potential was evaluated, following 5 days priming, using qualitative and quantitative histochemistry and RT-PCR.

Results: G-MSCs were CD14 , CD34 , CD45 , CD73 , CD90 , CD105 , and showed mesenchymal stem/progenitor cells' hallmarks, CFUs, and multilineage differentiation potential. Intracellular β-catenin significantly declined in the stimulated groups (P < 0.001, Friedman test). Cellular proliferation at 72 hours was most prominent in the control and inflammatory group [Median cell numbers (Q25/Q75); 6806 (4983/7312) and 5414 (4457/7230), respectively], followed by an upsurge in the retinol group. At 14 days, the retinol group exhibited the highest CFUs [Median CFUs (Q25/Q75); 35 (20/58), P = 0.043, Wilcoxon signed-rank]. Nanog was most expressed in the inflammatory and retinol group [Median gene expression/PGK1 (Q25/Q75); 0.0006 (0.0002/0.0014) and 0.0005 (0.0003/0.0008)]. Inflammation significantly upregulated Sox2 expression [0.0002 (0.0008/0.0005)], while its expression was diminished in the retinol and inflammatory/retinol group (P < 0.001, Friedman test). Inflammatory/retinol group exhibited the highest multilineage differentiation potential.

Conclusion: Controlled short-term inflammatory/retinol stimuli activate the Wnt/β-catenin pathway, affecting G-MSCs' pluripotency, proliferation, and differentiation. The present findings provide further insights into the inflammatory-regenerative interactions and their modulation potential for G-MSCs-mediated periodontal repair/regeneration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jre.12643DOI Listing
August 2019

Secreted frizzled-related protein 5 serum levels in human periodontitis-A nested case-control study.

J Clin Periodontol 2019 05 22;46(5):522-528. Epub 2019 Apr 22.

Department of Internal Medicine I, University Hospital Schleswig-Holstein, Kiel, Germany.

Aim: Recombinant secreted frizzled-related protein 5 (sFRP5) improved periodontal status in mice. Thus, this study aimed to investigate this finding in human periodontitis using an epidemiological approach.

Materials And Methods: sFRP5 and wnt5a concentrations were determined in human serum from the Food Chain Plus cohort using ELISAs. A total of 128 patients with periodontitis and tooth loss and 245 patients with periodontitis without tooth loss were compared to 373 sex-, smoker-, age- and BMI-matched individuals in a nested case-control design.

Results: Systemic sFRP5 serum levels were significantly lower in patients with periodontitis and tooth loss (2.5 [0.0-10.4] ng/ml, median [IQR]) compared to patients with periodontitis without tooth loss (6.0 [2.5-15.8] ng/ml, median [IQR], p = 0.04] and matched controls (7.0 [2.5-18.3] ng/ml, median [IQR], p = 0.02). No significant differences in sFRP5 serum levels were found among patients with periodontitis without tooth loss (6.0 [2.5-15.8] ng/ml, median [IQR]) and controls (3.1 [0.0-10.6] ng/ml, median [IQR], p = 0.06).

Conclusions: sFRP5 might serve as a novel biomarker for periodontitis severity. Modulating the inflammatory background of severe forms of periodontitis, in the time of precision medicine, needs to be revealed in further studies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jcpe.13087DOI Listing
May 2019

Whey Protein Complexes with Green Tea Polyphenols: Antimicrobial, Osteoblast-Stimulatory, and Antioxidant Activities.

Cells Tissues Organs 2018 24;206(1-2):106-118. Epub 2019 Jan 24.

Department of Molecular Biotechology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium,

Polyphenols are known for their antimicrobial activity, whilst both polyphenols and the globular protein β-lactoglobulin (bLG) are suggested to have antioxidant properties and promote cell proliferation. These are potentially useful properties for a tissue-engineered construct, though it is unknown if they are retained when both compounds are used in combination. In this study, a range of different microbes and an osteoblast-like cell line (human fetal osteoblast, hFOB) were used to assess the combined effect of: (1) green tea extract (GTE), rich in the polyphenol epigallocatechin gallate (EGCG), and (2) whey protein isolate (WPI), rich in bLG. It was shown that approximately 20-48% of the EGCG in GTE reacted with WPI. GTE inhibited the growth of Gram-positive bacteria, an effect which was potentiated by the addition of WPI. GTE alone also significantly inhibited the growth of hFOB cells after 1, 4, and 7 days of culture. Alternatively, WPI significantly promoted hFOB cell growth in the absence of GTE and attenuated the effect of GTE at low concentrations (64 µg/mL) after 4 and 7 days. Low concentrations of WPI (50 µg/mL) also promoted the expression of the early osteogenic marker alkaline phosphatase (ALP) by hFOB cells, whereas GTE inhibited ALP activity. Therefore, the antioxidant effects of GTE can be boosted by WPI, but GTE is not suitable to be used as part of a tissue-engineered construct due to its cytotoxic effects which negate any positive effect WPI has on cell proliferation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1159/000494732DOI Listing
September 2019

The periodontal stem/progenitor cell inflammatory-regenerative cross talk: A new perspective.

J Periodontal Res 2019 Apr 8;54(2):81-94. Epub 2018 Oct 8.

Clinic for Conservative Dentistry and Periodontology, School of Dental Medicine, Christian Albrechts University, Kiel, Germany.

Adult multipotent stem/progenitor cells, with remarkable regenerative potential, have been isolated from various components of the human periodontium. These multipotent stem/progenitor cells include the periodontal ligament stem/progenitor cells (PDLSCs), stem cells from the apical papilla (SCAP), the gingival mesenchymal stem/progenitor cells (G-MSCs), and the alveolar bone proper stem/progenitor cells (AB-MSCs). Whereas inflammation is regarded as the reason for tissue damage, it also remains a fundamental step of any early healing process. In performing their periodontal tissue regenerative/reparative activity, periodontal stem/progenitor cells interact with their surrounding inflammatory micro-environmental, through their expressed receptors, which could influence their fate and the outcome of any periodontal stem/progenitor cell-mediated reparative/regenerative activity. The present review discusses the current understanding about the interaction of periodontal stem/progenitor cells with their surrounding inflammatory micro-environment, elaborates on the inflammatory factors influencing their stemness, proliferation, migration/homing, differentiation, and immunomodulatory attributes, the possible underlying intracellular mechanisms, as well as their proposed relationship to the canonical and noncanonical Wnt pathways.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jre.12616DOI Listing
April 2019

IL-1/TNF- Inflammatory and Anti-Inflammatory Synchronization Affects Gingival Stem/Progenitor Cells' Regenerative Attributes.

Stem Cells Int 2017 9;2017:1349481. Epub 2017 Nov 9.

Clinic for Conservative Dentistry and Periodontology, School of Dental Medicine, Christian-Albrechts-Universität zu Kiel, Kiel, Germany.

Cytokines play major roles in tissue destruction/repair. The present study investigates proliferative and osteogenic differentiation potentials of gingival mesenchymal stem/progenitor cells (G-MSCs), influenced by IL-1/TNF- inflammatory/anti-inflammatory conditions. Human G-MSCs were isolated, characterized, and cultured in basic medium (control group, M1), in basic medium with IL-1, TNF-, and IFN- (inflammatory group, M2) and with IL-1ra/TNF-i added to M2 (anti-inflammatory group, M3). MTT tests at days 1, 3, and 7 and CFU assay at day 12 were conducted. Osteogenic differentiation was analyzed by bone-specific transcription factors (RUNX2), alkaline phosphatase (ALP), type I collagen (Col-I), osteopontin (OPN), and osteonectin (ON) expression at days 1, 3, 7, and 14 and Alizarin red staining at day 14. At day 3, the control group showed the highest cell numbers. At day 7, cell numbers in inflammatory and anti-inflammatory group outnumbered the control group. At day 12, CFUs decreased in the inflammatory and anti-inflammatory groups, with altered cellular morphology. The anti-inflammatory group demonstrated elevated bone-specific transcription factors at 14 days. After 14 days of osteogenic induction, calcified nodules in the anti-inflammatory group were higher compared to control and inflammatory groups. For regeneration, initial inflammatory stimuli appear essential for G-MSCs' proliferation. With inflammatory persistence, this positive effect perishes and is followed by a short-term stimulatory one on osteogenesis. At this stage, selective anti-inflammatory intervention could boost G-MSCs' differentiation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2017/1349481DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5700502PMC
November 2017

TLR expression profile of human alveolar bone proper-derived stem/progenitor cells and osteoblasts.

J Craniomaxillofac Surg 2017 Dec 18;45(12):2054-2060. Epub 2017 Sep 18.

Clinic for Conservative Dentistry and Periodontology, School of Dental Medicine, Christian Albrechts University, Arnold Heller Str. 3 (Haus 26), 24105 Kiel, Germany.

Alveolar bone proper-derived mesenchymal stem/progenitor cells (AB-MSCs) and alveolar osteoblasts (OBs) are pivotal cells with positive attributes in regenerative medicine. During regenerative approaches, AB-MSCs may interact with their surrounding environment via their expressed toll-like-receptors (TLRs). This study aimed to depict for the first time the TLRs expression profile of AB-MSCs and OBs. Cells were isolated from human alveolar bone proper, and STRO-1-immunomagnetically sorted to segregate AB-MSCs and OBs. Cell populations were separately seeded out to obtain single colony forming units (CFUs), and were characterized for CD14, CD34, CD45, CD73, CD90, CD105, and CD146 expression as well as for their multilineage differentiation potential. Following incubation of AB-MSCs and OBs in basic medium, their TLRs expression profiles were characterized at mRNA and protein levels. In contrast to OBs, AB-MSCs showed all predefined mesenchymal stem/progenitor cell characteristics. At a protein level, AB-MSCs showed a distinctive expression profile of TLRs 1, 2, 3, 4, 5, 6, 7, 8, and 10 in different quantities, without TLR9 expression. According to their median expression values, TLR2 was the highest expressed, followed by TLRs 4, 5, 7, 1, 10, 8, 3, and finally 6. In contrast, OBs did not express TLR3 and TLR9. According to their median expression values they further showed a different sequence of TLRs expression, with TLR2 highest expressed, followed by TLRs 10, 4, 7, 5, 1, 8, and 6. This study describes for the first time the characteristic TLRs expression profile of AB-MSCs as well as OBs, which could impact their specific sensitivity to pathogenic as well as body tissue compounds, and their therapeutic potential in-vivo.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcms.2017.09.007DOI Listing
December 2017

Animal Models for Periodontal Tissue Engineering: A Knowledge-Generating Process.

Tissue Eng Part C Methods 2017 12 25;23(12):900-925. Epub 2017 Oct 25.

2 Clinic for Conservative Dentistry and Periodontology, School of Dental Medicine, Christian Albrechts University , Kiel, Germany .

The human periodontium is a uniquely complex vital structure, supporting and anchoring the teeth in their alveolar sockets, thereby playing a decisive role in tooth homeostasis and function. Chronic periodontitis is a highly prevalent immune-inflammatory disease of the periodontium, affecting 15% of adult individuals, and is characterized by progressive destruction of the periodontal tooth-investing tissues, culminating in their irreversible damage. Current periodontal evidence-based treatment strategies achieve periodontal healing via repair processes, mostly combating the inflammatory component of the disease, to halt or reduce prospective periodontal tissue loss. However, complete periodontal tissue regeneration remains a hard fought-for goal in the field of periodontology and multiple in vitro and in vivo studies have been conducted, in the conquest to achieve a functional periodontal tissue regeneration in humans. The present review evaluates the current status of periodontal regeneration attempted through tissue-engineering concepts, ideal requirements for experimental animal models under investigation, the methods of induction and classification of the experimentally created periodontal defects, types of experimental defects employed in the diverse animal studies, as well as the current state of knowledge obtained from in vivo animal experiments, with special emphasis on large animal models.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/ten.TEC.2017.0130DOI Listing
December 2017

Investigation of the regenerative potential of necrotic mature teeth following different revascularisation protocols.

Aust Endod J 2017 Aug 2;43(2):73-82. Epub 2017 Aug 2.

Universitatsklinikum Schleswig-Holstein, Christian-Albrechts University, Kiel, Germany.

This study aimed to assess the revascularisation potential of necrotic mature teeth in a dog model following different protocols. Periapical infection was induced in 54 mature premolars. Teeth were distributed into seven groups: (1) Double-antibiotic-paste/Blood clot, (2) Ciprofloxacin/collagen, (3) Double-antibiotic-paste/Collagen, (4) Modified Tri-antibiotic-paste /collagen, (5) Ciprofloxacin/Gelfoam, (6) Double-antibiotic-paste/Gelfoam, and (7) Modified Triantibiotic- paste/Gelfoam. Positive and negative controls included infected and healthy teeth, respectively, (n = 12 roots/group). Canals were apically shaped to size 0.6 mm then disinfected for 1 month. Intra-canal bleeding was induced then scaffolds were applied for another month. Teeth and supporting bone were surgically sampled. Tissues were histologically scored and vimentin immuno-intensity was estimated. Ciprofloxacin and Double-antibiotic paste/Collagen resulted in significantly better corono-apical tissue ingrowths, vascularity, cementum formation and significantly lower inflammatory extents (P < 0.05).These groups also showed significantly higher Vimentin intensities, (P < 0.05). The applied protocols revascularised necrotic mature canals and reduced inflammation particularly in the Ciprofloxacin/collagen and Double-antibiotic-paste/collagen groups.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/aej.12210DOI Listing
August 2017

Porphyromonas gingivalis lipopolysaccharides affect gingival stem/progenitor cells attributes through NF-κB, but not Wnt/β-catenin, pathway.

J Clin Periodontol 2017 Nov 22;44(11):1112-1122. Epub 2017 Sep 22.

Clinic of Conservative Dentistry and Periodontology, School of Dental Medicine, Christian-Albrechts Universität at Kiel, Kiel, Germany.

Aim: This study investigates for the first time the effect of Porphyromonas gingivalis lipopolysaccharides (Pg-LPS) on proliferative/regenerative aptitudes of gingival stem/progenitor cells (G-MSCs).

Material And Methods: G-MSCs (n = 5) were treated by 0, 10 ng/ml, 100 ng/ml, 1 μg/ml or 10 μg/ml Pg-LPS. At 1 hour, Toll-like receptor 4 (TLR-4) expression and NF-κB and Wnt/β-catenin signalling pathways were examined. Colony-forming unit assay was conducted at day 12. At 24 and 48 hours, MTT test, ALP activity, mRNA for tumour necrosis factor-α (TNF-α), interleukin-6, collagen-I (Col-I), collagen-III, RUNX-2, alkaline phosphatase (ALP), osteonectin and protein expression of interleukin-6 and TNF-α were analysed.

Results: With increasing Pg-LPS, TLR-4 was upregulated, pNF-κB-p65 rose from median (Q25/Q75) 6.56% (4.19/7.90) to 13.02% (8.90/16.50; p = 0.002) and pNF-κB-p65/tNF-κB-p65 from 0.14(0.10/0.17) to 0.30(0.21/0.42; p = 0.002). pβ-Catenin, tβ-catenin and pβ-catenin/tβ-catenin showed no differences. Increasing Pg-LPS concentration increased cell numbers from 288.00(72.98/484.32) to 861.39 (540.41/1599.94; p = 0.002), ALP mRNA from 0.00(0.00/0.01) to 0.56(0.00/1.90; p = 0.004) and TNF-α from 32.47(12.11/38.57) to 45.32(28.68/48.65; p = 0.036). Over time, ALP activity increased from 0.89(0.78/0.95) to 1.90(1.83/2.09; p < 0.001), mRNA for TNF-α from 0.00(0.00/0.12) to 0.01(0.00/0.06; p = 0.007), mRNA for Col-I from 82.70(0.03/171.50) to 124.00(52.85/232.50; p = 0.019), while mRNA for RUNX-2 decreased from 1.73(0.92/3.20) to 0.84(0.48/1.47; p = 0.005).

Conclusions: Pg-LPS upregulated G-MSCs' proliferation, without attenuation of their regenerative potential. The effects were NF-κB, but not Wnt/β-catenin, pathway dependent.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jcpe.12777DOI Listing
November 2017

Effect of periodontitis history on implant success: a long-term evaluation during supportive periodontal therapy in a university setting.

Clin Oral Investig 2018 Jan 28;22(1):235-244. Epub 2017 Mar 28.

Clinic of Conservative Dentistry and Periodontology, University of Kiel, Kiel, Germany.

Objectives: The aim of this retrospective study was to evaluate the long-term implant survival in patients with a history of chronic periodontitis, during supportive periodontal therapy (SPT), compared to periodontally healthy patients.

Materials And Methods: Twenty-nine periodontitis patients (test) with SPT for ≥9 years and implant-supported restorations (≥5 years follow-up) were recruited and pair-matched with 29 periodontally healthy patients (control). Subjects in both groups were examined following active periodontal therapy and/or implantation (T1) (test 69 implants, control 76 implants) and at end of SPT or supportive postimplant therapy (T2). Differences between the groups in implant survival (primary outcome), mean marginal bone loss (MBL) and pocket probing depths (PPDs) (secondary outcomes) were evaluated.

Results: Implant survival over 5 years was 97.1% in test compared to 97.4% in control group (p = 0.562). MBL was significantly different (test 18.7 ± 18.2%; control 12.5 ± 21.3%) (p < 0.05). PPDs increased at T2 in both groups (test: T1 3.4 ± 1.0 mm; T2 4.2 ± 1.6 mm; control: T1 1.0 ± 1.2 mm; T2 2.9 ± 0.8 mm; p < 0.05 between groups). Prognostic factors for implant loss appeared to be the presence of residual periodontal pockets of ≥4 mm (OR 1.90), bone height (OR 1.81) and age (OR 1.16) at T1.

Conclusion: In terms of implant survival, no differences were observed between periodontitis and periodontally healthy patients. However, patients with history of periodontitis showed higher MBL and PPDs compared to periodontally healthy patients.

Clinical Relevance: The presence of a good periodontal maintenance program with preceding successful active periodontal treatment seems to be indispensable components of successful implant treatment in patients with history of chronic periodontitis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00784-017-2104-4DOI Listing
January 2018

Inhibition of Streptococcus mutans Growth and Biofilm Formation by Probiotics in vitro.

Caries Res 2017 25;51(2):87-95. Epub 2017 Jan 25.

Department of Operative and Preventive Dentistry, Charité - Universitätsmedizin Berlin, Berlin, Germany.

To exert anticaries effects, probiotics are described to inhibit growth and biofilm formation of cariogenic bacteria such as Streptococcus mutans (SM). We screened 8 probiotics and assessed how SM growth or biofilm formation inhibition affects cariogenicity of probiotic-SM mixed-species biofilms in vitro. Growth inhibition was assessed by cocultivating probiotics and 2 SM strains (ATCC 20532/25175) on agar. Probiotics were either precultured before SM cultivation (exclusion), or SM precultured prior to probiotic cultivation (displacement). Inhibition of SM culture growth was assessed visually. Inhibition of SM biofilm formation on bovine enamel was assessed using a continuous-flow short-term biofilm model, again in exclusion or displacement mode. The cariogenicity of mixed-species biofilms of SM with the most promising growth and biofilm formation inhibiting probiotic strains was assessed using an artificial mouth model, and enamel mineral loss (ΔZ) was measured microradiographically. We found limited differences in SM growth inhibition in exclusion versus displacement mode, and in inhibition of SM 20532 versus 25175. Results were therefore pooled. Lactobacillus acidophilus LA-5 inhibited significantly more SM culture growth than most other probiotics. L. casei LC-11 inhibited SM biofilm formation similarly to other alternatives but showed the highest retention of probiotics in the biofilms (p < 0.05). Mineral loss from SM monospecies biofilms (ΔZ = 9,772, 25th/75th percentiles: 6,277/13,558 vol% × µm) was significantly lower than from mixed-species SM × LA-5 biofilms (ΔZ = 24,578, 25th/75th percentiles: 19,081/28,768 vol% × µm; p < 0.01) but significantly higher than from SM × LC-11 biofilms (ΔZ = 4,835, 25th/75th percentiles: 263/7,865 vol% × µm; p < 0.05). Probiotics inhibiting SM culture growth do not necessarily reduce the cariogenicity of SM-probiotic biofilms. Nevertheless, SM biofilm formation inhibition may be relevant in the reduction of cariogenicity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1159/000452960DOI Listing
July 2018

TLR-induced immunomodulatory cytokine expression by human gingival stem/progenitor cells.

Cell Immunol 2018 04 10;326:60-67. Epub 2017 Jan 10.

Clinic for Conservative Dentistry and Periodontology, School of Dental Medicine, Christian-Albrecht's University, Kiel, Germany; Oral Medicine and Periodontology Department, Faculty of Oral and Dental Medicine, Cairo University, Egypt. Electronic address:

During therapeutic application, mesenchymal stem cells (MSCs) may interact with their environment via their expressed toll-like-receptors (TLRs) leading to pro- or anti-inflammatory immune responses. The present study aimed to describe the gingival margin-derived stem/progenitor cells' (G-MSCs) TLR-induced immune regulatory response to specific TLR agonists. Gingival cells were obtained, immunomagnetically sorted via anti-STRO-1 antibodies and seeded out to achieve colony forming units (CFUs). G-MSCs were investigated for stem cell characteristics and TLR expression. Specific TLR agonists were applied and m-RNA expression of pro- and anti-inflammatory factors was analyzed via real-time polymerase chain reaction. G-MSCs showed all characteristics of stem/progenitor cells. All TLR agonists induced pro-inflammatory cytokines, except for the TLR3 agonist, which significantly promoted the anti-inflammatory response. (p⩽0.05, Wilcoxon-Signed-Ranks-Test). TLR-induced immunomodulation by G-MSCs could impact their therapeutic potential in vivo. Two distinctive pro-inflammatory and an anti-inflammatory TLR-induced phenotypes of G-MSCs become noticeable in this study.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cellimm.2017.01.007DOI Listing
April 2018

Dental implants combined with sinus augmentation: What is the merit of bone grafting? A systematic review.

J Craniomaxillofac Surg 2016 Oct 2;44(10):1607-1617. Epub 2016 Jul 2.

Oral Medicine and Periodontology Department, Faculty of Oral and Dental Medicine Cairo University, Cairo, Egypt; Clinic for Conservative Dentistry and Periodontology(Head: Prof. Dr. C.E. Dörfer), School of Dental Medicine, Christian Albrechts University of Kiel, Germany. Electronic address:

Purpose: The aim of the present study was to systematically assess the current evidence on the effect of nongrafted compared to graft-assisted maxillary sinus floor elevation on implant survival/failure, endosinus bone gain, crestal bone loss, and bone density around dental implants.

Materials And Methods: MEDLINE-PubMed, Cochrane-CENTRAL, and EMBASE databases were searched up to November 2015 for randomized controlled trials (RCTs) and controlled clinical trials-(CCTs), evaluating dental implants placed in combination with maxillary sinus elevation without and with bone grafting. Implant survival/failure served as the primary outcome, whereas endosinus bone gain, crestal bone loss, and bone density around dental implants were secondary outcomes. To assess possible bias, the Cochrane risk of bias tool was used. Data were extracted and a meta-analysis performed where appropriate.

Results: Independent screening of 3180 papers resulted in six eligible experiments. Heterogeneity was observed among experiments. One experiment showed low, three unclear, and two a high risk of bias. The assessed outcomes showed no significant long-term differences between groups.

Conclusion: Within the limit of the current systematic review, nongrafted maxillary sinus floor elevation seems to be characterized by new bone formation and high implant survival rate comparable to bone-graft-assisted maxillary sinus floor augmentation. Further long-term studies are needed before definitive conclusions can be made.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcms.2016.06.022DOI Listing
October 2016

Impact of combined CO laser irradiation and fluoride on enamel and dentin biofilm-induced mineral loss.

Clin Oral Investig 2017 May 23;21(4):1243-1250. Epub 2016 Jun 23.

Department of Operative and Preventive Dentistry, Charité - Universitätsmedizin Berlin, Aßmannshauser Str. 4-6, 14197, Berlin,, Germany.

Objectives: The caries-protective effects of CO laser irradiation on dental enamel have been demonstrated using chemical demineralization models. We compared the effect of CO laser irradiation, sodium fluoride, or both on biofilm-induced mineral loss (∆Z) and Streptococcus mutans adhesion to enamel and dentin in vitro.

Materials And Methods: Ground, polished bovine enamel, and dentin samples were allocated to four groups (n = 12/group): no treatment (C); single 22,600-ppm fluoride (F) varnish (5 % NaF) application; single CO laser treatment (L) with short pulses (5 μs/λ = 10.6 μm); and laser and subsequent fluoride treatment (LF). Samples were sterilized and submitted to an automated mono-species S. mutans biofilm model. Brain heart infusion plus 5 % sucrose medium was provided eight times daily, followed by rinses with artificial saliva. After 10 days, bacterial numbers in biofilms were enumerated as colony-forming units/ml (CFU/ml) (n = 7/group). ∆Z was assessed using transversal microradiography (n = 12/group). Univariate ANOVA with post hoc Tukey honestly-significant-difference test was used for statistical analysis.

Results: Bacterial numbers were significantly higher on dentin than enamel (p < 0.01/ANOVA). On dentin, LF yielded significantly lower CFUs than other groups (p = 0.03/Tukey), while no differences between groups were found for enamel. The lowest ∆Z in enamel was observed for L (mean/SD 2036/1353 vol%×μm), which was not only significantly lower than C (9642/2452 vol%×μm) and F (7713/1489 vol%×μm) (p < 0.05) but also not significantly different from LF (3135/2628 vol%×μm) (p > 0.05). In dentin, only LF (163/227) significantly reduced ∆Z (p < 0.05).

Conclusion/clinical Relevance: CO laser irradiation did not increase adhesion of S. mutans in vitro. Laser treatment alone protected enamel against biofilm-induced demineralization, while a combined laser-fluoride application was required to protect dentin.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00784-016-1893-1DOI Listing
May 2017

Gingival Mesenchymal Stem/Progenitor Cells: A Unique Tissue Engineering Gem.

Stem Cells Int 2016 29;2016:7154327. Epub 2016 May 29.

Clinic of Conservative Dentistry and Periodontology, Christian Albrechts University of Kiel, Arnold Heller Straße 3, Haus 26, 24105 Kiel, Germany.

The human gingiva, characterized by its outstanding scarless wound healing properties, is a unique tissue and a pivotal component of the periodontal apparatus, investing and surrounding the teeth in their sockets in the alveolar bone. In the last years gingival mesenchymal stem/progenitor cells (G-MSCs), with promising regenerative and immunomodulatory properties, have been isolated and characterized from the gingival lamina propria. These cells, in contrast to other mesenchymal stem/progenitor cell sources, are abundant, readily accessible, and easily obtainable via minimally invasive cell isolation techniques. The present review summarizes the current scientific evidence on G-MSCs' isolation, their characterization, the investigated subpopulations, the generated induced pluripotent stem cells- (iPSC-) like G-MSCs, their regenerative properties, and current approaches for G-MSCs' delivery. The review further demonstrates their immunomodulatory properties, the transplantation preconditioning attempts via multiple biomolecules to enhance their attributes, and the experimental therapeutic applications conducted to treat multiple diseases in experimental animal models in vivo. G-MSCs show remarkable tissue reparative/regenerative potential, noteworthy immunomodulatory properties, and primary experimental therapeutic applications of G-MSCs are very promising, pointing at future biologically based therapeutic techniques, being potentially superior to conventional clinical treatment modalities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2016/7154327DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4903147PMC
June 2016

Removal of simulated biofilm: an evaluation of the effect on root surfaces roughness after scaling.

Clin Oral Investig 2017 May 27;21(4):1021-1028. Epub 2016 May 27.

Clinic for Conservative Dentistry and Periodontology, Christian-Albrechts-University of Kiel, Kiel, Germany.

Background: Despite the development of less invasive devices, a debate exists about the benefits and risks of hand versus powered root surface instrumentation used in supportive periodontal therapy (SPT). The aim of the in vitro study was to differentially compare plaque removal efficacy and root surface roughening of newly developed sonic, ultrasonic scaler, and curettes in the hands of experienced versus less experienced operators.

Materials And Methods: Sonic (AIR), ultrasonic devices (TIG), and double-gracey curettes (GRA) were utilized by seven experienced (EO) and four less experienced operators (LO) for root surface instrumentation of standardized plastic teeth on manikins' heads in a randomized sequence. The proportion of residual simulated plaque (RSP area in %) was planimetrically assessed, and the average root surface roughness produced (Ra and ∆Ra in μm) was measured by a precision profilometer.

Results: The uninstrumented root surfaces showed a Ra of (median (Q25/Q75)) 1.00 μm (0.83/1.16). Following instrumentation, EO left significantly less RSP than LO regardless of the used instruments (20.00 % (10.00/34.00) vs. 26.00 % (12.00/44.00) p < 0.001), whereas the ∆Ra values (0.29 μm (-0.04/0.96) vs. 0.35 μm (-0.04/1.01), p = 0.237) failed to show significant differences. The surface roughness was higher with GRA followed by AIR then TIG regardless of operators' experience (p < 0.001).

Conclusion: Within the limits of the present study, the sonic device was most efficient in plaque removal, while the ultrasonic device produced the least surface roughness.

Clinical Relevance: All three tested instruments seem effective in the mechanical root debridement during SPT, whereat the ultrasonic device show the smoothest root surface of all.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00784-016-1861-9DOI Listing
May 2017