Modified minimally invasive surgical technique with clindamycin-augmented or non-augmented platelet-rich fibrin in periodontal regeneration: A randomized clinical trial.

AIM: Injectable platelet-rich fibrin (I-PRF), a second-generation platelet concentrate, is widely used to enhance soft and hard tissue healing alone or in combination with biomaterials, relying on its harboring of various pivotal growth/differentiation factors. This randomized trial assessed the effect of clindamycin (CLN) augmented injectable platelet-rich fibrin (I-PRF) with modified minimally invasive surgical technique (M-MIST) versus I-PRF alone with M-MIST on the clinical and radiographic parameters in the management of periodontal intra-bony defects in patients with stage-III grade B periodontitis. METHODS: This is a 9-month parallel-grouped, two arm, double-blinded, randomized controlled trial (RCT) that included 28 patients (n = 28) with stage-III grade B periodontitis, who were allocated randomly to test- (CLN/I-PRF + M-MIST, 50 µL of CLN per 1 mL of I-PRF; n = 14) or control-group (I-PRF + M-MIST; n = 14). Clinical attachment level (CAL; primary outcome), probing depth (PD), gingival margin level (GML), plaque index (PI), and gingival index (GI) were recorded at baseline, 3, 6, and 9 months, whereas radiographic parameters radiographic linear defect depth (RLDD), and radiographic defect area (RDA) were recorded at baseline, 6, and 9 months. The CLN release kinetics from the I-PRF were further characterized. RESULTS: Compared to baseline, both groups independently demonstrated significant improvements in CAL, PD, GML, GI, PI, RLDD and BDA at 3, 6 and 9 months (p < .05). A significant reduction in CAL measurements was noticeable in the CLN/I-PRF + M-MIST and I-PRF + M-MIST group independently over time (p < .05). CLN/I-PRF + M-MIST showed significantly lower CAL than PRF + M-MIST group at baseline, after three as well as 9 months (p < .05). Intergroup comparisons at 9 months demonstrated that CAL-gain was non-significant between groups (p > .05), GI significantly lower in CLN/I-PRF + M-MIST, whereas PD-reduction significantly higher I-PRF + M-MIST group (p < .05). CLN was steadily released for the I-PRF for up to 48 h, with a peak concentration at 24 h, which then gradually declined till the seventh day. CONCLUSIONS: I-PRF with M-MIST provided significant clinical and radiographic improvement up to 9 months postoperatively in stage-III grade B periodontitis. CLN, at the applied concentration and release duration, does not appear to further positively impact these observed I-PRF effects.

Molecular Basis beyond Interrelated Bone Resorption/Regeneration in Periodontal Diseases: A Concise Review.

Periodontitis is the sixth most common chronic inflammatory disease, destroying the tissues supporting the teeth. There are three distinct stages in periodontitis: infection, inflammation, and tissue destruction, where each stage has its own characteristics and hence its line of treatment. Illuminating the underlying mechanisms of alveolar bone loss is vital in the treatment of periodontitis to allow for subsequent reconstruction of the periodontium. Bone cells, including osteoclasts, osteoblasts, and bone marrow stromal cells, classically were thought to control bone destruction in periodontitis. Lately, osteocytes were found to assist in inflammation-related bone remodeling besides being able to initiate physiological bone remodeling. Furthermore, mesenchymal stem cells (MSCs) either transplanted or homed exhibit highly immunosuppressive properties, such as preventing monocytes/hematopoietic precursor differentiation and downregulating excessive release of inflammatory cytokines. In the early stages of bone regeneration, an acute inflammatory response is critical for the recruitment of MSCs, controlling their migration, and their differentiation. Later during bone remodeling, the interaction and balance between proinflammatory and anti-inflammatory cytokines could regulate MSC properties, resulting in either bone formation or bone resorption. This narrative review elaborates on the important interactions between inflammatory stimuli during periodontal diseases, bone cells, MSCs, and subsequent bone regeneration or bone resorption. Understanding these concepts will open up new possibilities for promoting bone regeneration and hindering bone loss caused by periodontal diseases.

Ascorbic Acid/Retinol and/or Inflammatory Stimuli's Effect on Proliferation/Differentiation Properties and Transcriptomics of Gingival Stem/Progenitor Cells.

The present study explored the effects of ascorbic-acid (AA)/retinol and timed inflammation on the stemness, the regenerative potential, and the transcriptomics profile of gingival mesenchymal stem/progenitor cells' (G-MSCs). STRO-1 (mesenchymal stem cell marker) immuno-magnetically sorted G-MSCs were cultured in basic medium (control group), in basic medium with IL-1ß (1 ng/mL), TNF-α (10 ng/mL) and IFN-γ (100 ng/mL, inflammatory-medium), in basic medium with AA (250 µmol/L) and retinol (20 µmol/L) (AA/retinol group) or in inflammatory medium with AA/retinol (inflammatory/AA/retinol group; n = 5/group). The intracellular levels of phosphorylated and total ß-Catenin at 1 h, the expression of stemness genes over 7 days, the number of colony-forming units (CFUs) as well as the cellular proliferation aptitude over 14 days, and the G-MSCs' multilineage differentiation potential were assessed. Next-generation sequencing was undertaken to elaborate on up-/downregulated genes and altered intracellular pathways. G-MSCs demonstrated all mesenchymal stem/progenitor cells characteristics. Controlled inflammation with AA/retinol significantly elevated NANOG (p < 0.05). The AA/retinol-mediated reduction in intracellular phosphorylated ß-Catenin was restored through the effect of controlled inflammation (p < 0.05). Cellular proliferation was highest in the AA/retinol group (p < 0.05). AA/retinol counteracted the inflammation-mediated reduction in G-MSCs' clonogenic ability and CFUs. Amplified chondrogenic differentiation was observed in the inflammatory/AA/retinol group. At 1 and 3 days, the differentially expressed genes were associated with development, proliferation, and migration (FOS, EGR1, SGK1, CXCL5, SIPA1L2, TFPI2, KRATP1-5), survival (EGR1, SGK1, TMEM132A), differentiation and mineral absorption (FOS, EGR1, MT1E, KRTAP1-5, ASNS, PSAT1), inflammation and MHC-II antigen processing (PER1, CTSS, CD74) and intracellular pathway activation (FKBP5, ZNF404). Less as well as more genes were activated the longer the G-MSCs remained in the inflammatory medium or AA/retinol, respectively. Combined, current results point at possibly interesting interactions between controlled inflammation or AA/retinol affecting stemness, proliferation, and differentiation attributes of G-MSCs.

Cell-Based Transplantation versus Cell Homing Approaches for Pulp-Dentin Complex Regeneration.

Regenerative dentistry has paved the way for a new era for the replacement of damaged dental tissues. Whether the causative factor is dental caries, trauma, or chemical insult, the loss of the pulp vitality constitutes one of the major health problems worldwide. Two regenerative therapies were introduced for a fully functional pulp-dentin complex regeneration, namely, cell-based (cell transplantation) and cell homing (through revascularization or homing by injection of stem cells in situ or intravenously) therapies, with each demonstrating advantages as well as drawbacks, especially in clinical application. The present review is aimed at elaborating on these two techniques in the treatment of irreversibly inflamed or necrotic pulp, which is aimed at regenerating a fully functional pulp-dentin complex.

Effect of locally delivered adjunctive antibiotics during surgical periodontal therapy: a systematic review and meta-analysis.

AIM: The present study aimed to systematically assess current evidence on effects of locally delivered antibiotics during periodontal surgery compared to periodontal surgery alone on clinical attachment level (CAL) gain, probing pocket depth (PPD) reduction, recession depth (RD) changes, gingival index (GI), bleeding on probing (BOP), and plaque index (PI). METHODOLOGY: MEDLINE-PubMed, Cochrane-CENTRAL and Scopus databases were searched up to April 2021 for randomized clinical trials (RCT), evaluating effects of locally delivered antibiotics during periodontal surgery. CAL gain served as primary, while PPD reduction, RD changes, GI and PI as secondary outcomes. The Cochrane Risk of Bias Tool was used to assess possible bias. Data were extracted, and meta-analysis was performed where appropriate. RESULT: Screening of 2314 papers resulted in nine eligible studies. No adverse events were reported. Data on outcome variables were pooled and analyzed using generic inverse variance model and presented as weighted mean difference (WMD) and 95% confidence interval (95% CI). Statistically significant improvements in favor of antibiotics' delivery were observed in studies with follow-up of ≤6 months for CAL gain (WMD = 0.61 mm (95% CI [0.07, 1.14]; p = 0.03), PPD reduction (WMD = 0.41 mm (95% CI [0.02, 0.80]; p = 0.04)) and BOP (WMD = -28.47% (95% CI [-33.00, -23.94]); p < 0.001), while for GI improvements were notable for >6 to 12 months (WMD = -0.27 (95% CI [-0.49, -0.06]; p = 0.01)). CONCLUSION: Within the current review's limitations, locally delivered antibiotics during surgical periodontal therapy results in post-surgical improvements for CAL, PPD, and BOP (≤6 months) with a longer-lasting GI improvement. Further randomized controlled trials are needed with true periodontal end-points to assess the ideal antibiotic agent, dosage, and delivery methods. CLINICAL RELEVANCE: Local delivery of antibiotics during periodontal surgery improved clinical parameters for up to 6-month follow-up, with beneficial longer effects on gingival inflammation. Within the current study's limitation, the presented evidence could support the elective usage of locally delivered antibiotics during surgical periodontal therapy.

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

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, 103 U/mL interferon gamma, 50 ng/mL tumor necrosis factor alpha, and 3 × 103 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.

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

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.

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

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-1ß/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-1ß (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). ß-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 ß-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/ß-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.

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

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.

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

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.

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

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/ß-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). pß-Catenin, tß-catenin and pß-catenin/tß-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/ß-catenin, pathway dependent.

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

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.

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

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.

Toll-like Receptor Expression Profile of Human Dental Pulp Stem/Progenitor Cells.

INTRODUCTION: Human dental pulp stem/progenitor cells (DPSCs) show remarkable regenerative potential in vivo. During regeneration, DPSCs may interact with their inflammatory environment via toll-like receptors (TLRs). The present study aimed to depict for the first time the TLR expression profile of DPSCs. METHODS: Cells were isolated from human dental pulp, STRO-1-immunomagnetically sorted, and seeded out to obtain single colony-forming units. DPSCs were characterized for CD14, CD34, CD45, CD73, CD90, CD105, and CD146 expression and for their multilineage differentiation potential. After incubation of DPSCs in basic or inflammatory medium (interleukin-1ß, interferon-γ, interferon-α, tumor necrosis factor-α), TLR expression profiles were generated (DPSCs and DPSCs-i). RESULTS: DPSCs showed all characteristics of stem/progenitor cells. In basic medium DPSCs expressed TLRs 1-10 in different quantities. The inflammatory medium upregulated the expression of TLRs 2, 3, 4, 5, and 8, downregulated TLRs 1, 7, 9, and 10, and abolished TLR6. CONCLUSIONS: The current study describes for the first time the distinctive TLR expression profile of DPSCs in uninflamed and inflamed conditions.

Periodontal regeneration employing gingival margin-derived stem/progenitor cells in conjunction with IL-1ra-hydrogel synthetic extracellular matrix.

AIM: This study investigated the periodontal regenerative potential of gingival margin-derived stem/progenitor cells (G-MSCs) in conjunction with IL-1ra-releasing hyaluronic acid synthetic extracellular matrix (HA-sECM). MATERIALS AND METHODS: Periodontal defects were induced at four sites in eight miniature pigs in the premolar/molar area (-4 weeks). Autologus G-MSCs were isolated from the free gingival margin and magnetically sorted, using anti-STRO-1 antibodies. Colony formation and multilineage differentiation potential were tested. The G-MSCs were expanded and incorporated into IL-1ra-loaded/unloaded HA-sECM. Within every miniature pig, four periodontal defects were randomly treated with IL-1ra/G-MSCs/HA-sECM (test group), G-MSCs/HA-sECM (positive-control), scaling and root planing (SRP; negative control-1) or left untreated (no-treatment group; negative control 2). Differences in clinical attachment level (ΔCAL), probing depth (ΔPD), gingival recession (ΔGR), radiographic defect volume (ΔRDV), and changes in bleeding on probing (BOP) between baseline and 16 weeks post-transplantation, as well as periodontal attachment level (PAL), junctional epithelium length (JE), connective tissue adhesion (CTA), cementum regeneration (CR) and bone regeneration (BR) at 16 weeks post-transplantation were evaluated. RESULTS: Isolated G-MSCs showed stem/progenitor cell characteristics. IL-1ra loaded and unloaded G-MSCs/HA-sECM showed higher ΔCAL, ΔPD, ΔGR, PAL, CR and BR as well as a lower JE compared to their negative controls and improved BOP. CONCLUSION: G-MSCs in conjunction with IL-1ra-loaded/unloaded HA-sECM show a significant periodontal regenerative potential.

Stem Cell Transplantation for Pulpal Regeneration: A Systematic Review.

For treating pulpal pathological conditions, pulpal regeneration through transplanted stem/progenitor cells might be an alternative to conventional root canal treatment. A number of animal studies demonstrated beneficial effects of stem/progenitor cell transplantation for pulp-dentin complex regeneration, that is, pulpal tissue, neural, vascular, and dentinal regeneration. We systematically reviewed animal studies investigating stem/progenitor cell-mediated pulp-dentin complex regeneration. Studies quantitatively comparing pulp-dentin complex regeneration after transplantation of stem/progenitor cells versus no stem/progenitor cell transplantation controls in intraoral in vivo teeth animal models were analyzed. The following outcomes were investigated: regenerated pulp area per root canal total area, capillaries per total surface, regenerated dentinal area per total defect area, and nerves per total surface. PubMed and EMBASE were screened for studies published until July 2014. Cross-referencing and hand searching were used to identify further articles. Standardized mean differences (SMD) and 95% confidence intervals (95% CI) were calculated using random-effects meta-analysis. To assess possible bias, SYRCLE's risk of bias tool for animal studies was used. From 1364 screened articles, five studies (representing 64 animals) were included in the quantitative analysis. Risk of bias of all studies was high. Stem/progenitor cell-transplanted pulps showed significantly larger regenerated pulp area per root canal total area (SMD [95% CI]: 2.28 [0.35-4.21]) and regenerated dentin area per root canal total area (SMD: 6.91 [5.39-8.43]) compared with no stem/progenitor cell transplantation controls. Only one study reported on capillaries per or nerves per total surface and found both significantly increased in stem/progenitor cell-transplanted pulps compared with controls. Stem/progenitor cell transplantation seems to enhance pulp-dentin complex regeneration in animal models. Due to limited data quantity and quality, current evidence levels are insufficient for further conclusions.

Effect of Emdogain enamel matrix derivative and BMP-2 on the gene expression and mineralized nodule formation of alveolar bone proper-derived stem/progenitor cells.

The objective of this study was to evaluate the effect of Emdogain (Enamel Matrix Derivative, EMD) and Bone Morphogenetic Protein-2 (BMP-2), either solely or in combination, on the gene expression and mineralized nodule formation of alveolar bone proper-derived stem/progenitor cells. Stem/progenitor cells were isolated from human alveolar bone proper, magnetically sorted using STRO-1 antibodies, characterized flowcytometrically for their surface markers' expression, and examined for colony formation and multilineage differentiation potential. Subsequently, cells were treated over three weeks with 100 µg/ml Emdogain (EMD-Group), or 100 ng/ml BMP-2 (BMP-Group), or a combination of 100 ng/ml BMP-2 and 100 µg/ml Emdogain (BMP/EMD-Group). Unstimulated stem/progenitor cells (MACS(+)-Group) and osteoblasts (OB-Group) served as controls. Osteogenic gene expression was analyzed using RTq-PCR after 1, 2 and 3 weeks (N = 3/group). Mineralized nodule formation was evaluated by Alizarin-Red staining. BMP and EMD up-regulated the osteogenic gene expression. The BMP Group showed significantly higher expression of Collagen-I, III, and V, Alkaline phosphatase and Osteonectin compared to MACS(+)- and OB-Group (p < 0.05; Two-way ANOVA/Bonferroni) with no mineralized nodule formation. Under in-vitro conditions, Emdogain and BMP-2 up-regulate the osteogenic gene expression of stem/progenitor cells. The combination of BMP-2 and Emdogain showed no additive effect and would not be recommended for a combined clinical stimulation.

Isolation and characterization of multipotent postnatal stem/progenitor cells from human alveolar bone proper.

In the search for an ideal minimally-invasive multipotent postnatal stem cells' source, the aim of the present study was to isolate and characterize multipotent postnatal stem/progenitor cells from the human alveolar bone proper tissue of the oral cavity. Cells were isolated from human alveolar bone parts, immunomagnetically sorted using STRO-1 antibodies and characterized flow cytometrically for the expression of CD14, CD34, CD45, CD73, CD90, CD105, CD146/MUC18 and STRO-1 surface markers. Colony-formation and multilineage differentiation potential were tested. Mineralized tissue marker expression was examined using real time polymerase chain reaction (PCR). The cells were plastic-adherent and showed colony-formation. Cells expressed the surface markers CD73, CD90, CD105, STRO-1 and CD146/MUC18, while lacking the expression of the hematopoietic markers CD14, CD34 and CD45. Cells could be differentiated into osteoblastic, adipocytic and chondroblastic lineages. Unstimulated cells expressed alkaline phosphatase (ALP), type I, III and V collagens, osteonectin and osteocalcin in a very distinctive pattern. This study presents a practical and minimally-invasive scheme for the isolation of multipotent postnatal stem/progenitor cells from the human alveolar bone tissue of the oral cavity.

Local application of hyaluronan gel in conjunction with periodontal surgery: a randomized controlled trial.

Hyaluronic acid application has been proven to be beneficial in a number of medical disciplines. The aim of the current study was to clinically evaluate the effect of local application of hyaluronan gel in conjunction with periodontal surgery. Fourteen patients with chronic periodontitis having four interproximal intrabony defects (≥3 mm) with probing depth values >5 mm were included in this split-mouth study. Following initial nonsurgical periodontal therapy and re-evaluation, defects were randomly assigned to be treated with modified Widman flap (MWF) surgery in conjunction with either 0.8% hyaluronan gel (test) or placebo gel (control) application. Clinical attachment level (CAL), probing depth (PD), gingival recession (GR), plaque index (PI), and bleeding on probing (BOP) values were taken at baseline and 3 and 6 months. Differences between test and control sites were evaluated using a Wilcoxon signed-rank and a McNemar test. A Friedman and a Cochran test were used to test equal ranks over time. Statistically significant differences were noted for CAL and GR (P < 0.05) in favor of the test sites. No significant differences were found regarding PD, BOP, or PI values (P > 0.05). Hyaluronan gel application in conjunction with periodontal surgery appears to result in significant improvement of CAL and in a reduction in GR. Hyaluronan gel application appears to improve the clinical outcome of MWF surgery.