Comparison of Periodontal Ligament Stem Cells with Mesenchymal Stem Cells from Other Sources: A Scoping Systematic Review of In vitro and In vivo Studies

OBJECTIVE

The application of stem cells in regenerative medicine depends on their biological properties. This scoping review aimed to compare the features of periodontal ligament stem cells (PDLSSCs) with stem cells derived from other sources.

DESIGN

An electronic search in PubMed/Medline, Embase, Scopus, Google Scholar and Science Direct was conducted to identify in vitro and in vivo studies limited to English language.

RESULTS

Overall, 65 articles were included. Most comparisons were made between bone marrow stem cells (BMSCs) and PDLSCs. BMSCs were found to have lower proliferation and higher osteogenesis potential in vitro and in vivo than PDLSCs; on the contrary, dental follicle stem cells and umbilical cord mesenchymal stem cells (UCMSCs) had a higher proliferative ability and lower osteogenesis than PDLSCs. Moreover, UCMSCs exhibited a higher apoptotic rate, hTERT expression, and relative telomerase length. The immunomodulatory function of adipose-derived stem cells and BMSCs was comparable to PDLSCs. Gingival mesenchymal stem cells showed less sensitivity to long-term culture. Both pure and mixed gingival cells had lower osteogenic ability compared to PDLSCs. Comparison of dental pulp stem cells (DPSCs) with PDLSCs regarding proliferation rate, osteo/adipogenesis, and immunomodulatory properties was contradictory; however, in vivo bone formation of DPSCs seemed to be lower than PDLSCs.

CONCLUSION

In light of the performed comparative studies, PDLSCs showed comparable results to stem cells derived from other sources; however, further in vivo studies are needed to determine the actual pros and cons of stem cells in comparison to each other.

Development of a Novel Histatin-5 Mucoadhesive Gel for the Treatment of Oral Mucositis: In Vitro Characterization and In Vivo Evaluation

Antimicrobial peptides have appeared to be promising candidates for therapeutic purposes due to their broad antimicrobial activity and non-toxicity. Histatin-5 (Hst-5) is a notable salivary antimicrobial peptide that exhibited therapeutic properties in the oral cavity. Oral mucositis is an acute inflammation of the oral cavity, following cancer therapy. The current treatment methods of oral mucositis have low effectiveness. The aim of this study was to design, formulate and characterize a mucoadhesive gel delivery system for Hst-5 usage in the treatment of oral mucositis. Carbopol 934 and hydroxypropyl methylcellulose (HPMC) have been used in the development of a Hst-5 mucoadhesive gel that was optimized by using Box-Behnken design. The optimized formulation was evaluated in-vitro, based on mucoadhesive strength, viscoelasticity, spreadability, release rate, peptide secondary structure analysis, antimicrobial activity, and storage stability. The efficacy of Hst-5 gel was assessed in vivo in a chemotherapy-induced mucositis model. The results showed a sustained release of Hst-5 from the new formulation. Hst-5 gel exerted antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. The histopathological, immunohistochemical and statistical analysis showed that the Hst-5 gel had wound healing activity in vivo. The findings of this study indicate that the mentioned compound possesses promising potential as a novel and efficient therapeutic agent in managing oral mucositis. Moreover, the results suggest that the compound is commercially feasible for further development and utilization.

Amniotic Allograft, A Possible Alternative to Free Gingival Graft in Improving Attached Gingiva Width: A Randomized Controlled Clinical Trial

Background

Years of research have well demonstrated the pivotal role the attached gingiva plays in maintaining of periodontal health.

Objective

This study aimed to compare the efficacy of two technics, amniotic allograft and free gingival graft (FGG), in improving the attached gingiva width (AGW) around the teeth.

Methods

In this randomized controlled clinical trial study, 28 patients all in need of increased AGW were randomly halved and assigned to a test group receiving the amniotic allograft and a control group treated by a palatal FGG. Following the operation, the mean AGW, graft shrinkage, and color match were assessed and photographed at various intervals (1, 2, 6, and 12 weeks). The level of pain was also evaluated based on the visual analog scale (VAS).

Results

The AGW was not significantly different between the two groups in 2, 6 and, 12 weeks postoperatively (P=0.17, 0.73, 0.76 respectively). The same applied to the amount of shrinkage between the two groups at the intervals (p=0.38, p=0.57 and p=0.52 respectively). The amniotic allograft group was superior (not significantly) in terms of the color match (p=0.59, p=0.31 and p=0.18 respectively). However, it was found to have significantly lower VAS pain scores than did the control group (p <0.05).

Conclusion

Application of the amniotic allograft could decrease the postoperative pain as well as discomfort and effectively increase the AGW. Therefore, given the drawbacks of FGG, the amniotic allograft can be considered as a viable alternative.

Effect of Amniotic Membrane Dressing on Pain and Healing of Palatal Donor Site: A Randomized Controlled Trial

BACKGROUND

Free gingival graft is the most commonly practiced predictable technique for gingival augmentation.

OBJECTIVE

To assess the effectiveness of human amniotic membrane, a biological dressing, on wound healing and post-operative pain after its application on the palatal donor site after free gingival graft surgery.

METHODS

Of 27 eligible patients, 15 were randomized into a test group and received human amniotic membrane dressing sutured over their palatal donor site; 12 were randomized into a control group in whom the palatal donor site was only sutured. Standard clinical photographs were taken at 7, 14, and 21 days post-operatively and evaluated by 3 periodontists. The pain score at the donor site was assessed by a visual analog score; the number of analgesics taken was also recorded.

RESULTS

The mean color match scores were higher in the test group than the control group at 14 (p<0.01) and 21 days after surgery (p=0.02). The difference in tissue texture (p=0.01) and inflammation (p=0.02) between the two groups was only significant on day 14 (p<0.05). The pattern of pain relief was better in the test group compared with the control group, especially in first days, although the differences were not significant in terms of the number of analgesics taken or the pain score.

CONCLUSION

Application of human amniotic membrane can accelerate wound healing and may decrease post-operative pain and discomfort by a limited amount.

PerioVax3, a key antigenic determinant with immunoprotective potential against periodontal pathogen

Treponema (T.) denticola is one of the key etiological agents in the development of periodontitis. The major outer sheath protein (Msp) of T. denticola has been shown to mediate pathogenesis and to facilitate adhesion of T. denticola to mucosal surfaces. This study aimed to find short polypeptides in the amino acid sequence of Msp which may be immunogenic and might elicit protective antisera against T. denticola. The complete msp sequence was divided into six fragments and the corresponding genes were cloned and expressed. Antisera against the polypeptides were raised in rabbits and fragment 3 (F3), hereinafter called PerioVax3 was the most potent fragment of the Msp in terms of yielding high titer antiserum. An adhesion assay was done to examine the inhibitory effects of antisera on the attachment of T. denticola to human gingival fibroblasts (HGFs) and human fibronectin. Antiserum against PerioVax3 significantly inhibited attachment of T. denticola to the substratum. Also, antiserum against PerioVax3 inhibited detachment of HGFs upon T. denticola exposure. To begin examining the clinical relevance of this work, blood samples from 12 sever periodontitis patients were collected and the sera were used in western blotting against the recombinant polypeptides. Periodontitis patient antisera exclusively detected PerioVax3 in western blotting. The data suggest that PerioVax3 carries epitopes that may trigger humoral immunity against T. denticola, which may protect against its adhesion functions. The complexity of periodontitis suggests that PerioVax3 may be considered for testing as a component of an experimental multivalent periodontal vaccine in further preclinical and clinical studies.

Effect of TNF-α Blockade in Gingival Crevicular Fluid on Periodontal Condition of Patients with Rheumatoid Arthritis

BACKGROUND

Periodontitis and rheumatoid arthritis (RA) share a number of clinical and pathologic features, one of which is the presence of the tumor necrosis factor alpha (TNF-α)-induced bone resorption that is involved in the pathogenesis of both.

OBJECTIVES

To investigate the effect of TNF-α blockade on periodontal conditions in patients with active RA.

METHOD

The periodontal statuses of 36 patients (26 females, 10 males) diagnosed with active RA were evaluated both before and after anti-TNF-α therapy. Gingival index, bleeding on probing (BOP), probing pocket depth (PPD), oral hygiene index (OHI), and levels of TNF-α in gingival crevicular fluid (GCF) were measured at the baseline and 6 weeks after the treatment. Wilcoxon signed ranked test was used for statistical analyses.

RESULTS

Based on OHI (p=0.860), the level of plaque control did not change during the study period, but there was a significant reduction in gingival inflammation based on the mean BOP (p=0.049) and GI (p=0.036) before and after 6 weeks of anti-TNF-α therapy. The mean PPD index did not significantly differ at the baseline and 6 weeks after treatment (p=0.126).

CONCLUSION

Anti-TNF-α therapy might have a desirable effect on periodontal conditions and might reduce TNF-α level in GCF of patients with RA.

Antimicrobial effect of chlorhexidine on Aggregatibacter actinomycetemcomitans biofilms associated with peri-implantitis

Background. This study aimed to assessthe antimicrobial effect of chlorhexidine (CHX) on Aggregatibacter actinomycetemcomitans biofilms isolated from subgingival plaque of peri-implantitis lesions.

Methods. Thirteen patients requiring peri-implantitis treatment were consecutively selected and their subgingival biofilm was collected by inserting fine sterile paper points into peri-implant pockets for 15 seconds. A. actinomycetemcomitans was isolated from the subgingival biofilm and cultured. In this study, the standard strain of A. actinomycetemcomitans served as the positive control group and a blank disc impregnated with water served as the negative control; 0.1 mL of the bacterial suspension was cultured on specific culture medium and blank discs (6 mm in diameter) impregnated with 0.2%CHX mouthrinse (Behsa Pharmaceutical Co.) and negative control discs were placed on two sides of the bacterial culture plate. The size of growth inhibition zone was measured by a blinded independent observer in millimetres.

Results. According to the results of disc diffusion test, the mean diameter of growth inhibition zone of A. actinomycetemcomitans around discs impregnated with CHX was larger in both standard (positive control) and biofilm samples of A. actinomycetemcomitans compared to the negative control group (blank disc) (P<0.001).

Conclusion. Use of0.2% CHX mouthwash had antibacterial effects on A. actinomycetemcomitans species isolated from peri-implantitis sites.

Histopathological Comparison between Bone Marrow- and Periodontium-derived Stem Cells for Bone Regeneration in Rabbit Calvaria

BACKGROUND

Periodontitis is an important oral disease. Stem cell therapy has found its way in treatment of many diseases.

OBJECTIVE

To evaluate the regenerative potential of periodontal ligament-derived stem cells (PDLSCs) and osteoblast differentiated from PDLSC in comparison with bone marrow-derived mesenchymal stem cells (BM-MSCs) and pre-osteoblasts in calvarial defects.

METHODS

After proving the existence of surface markers by flow cytometry, BM-MSCs were differentiated into osteoblasts. 5 defects were made on rabbit calvaria. 3 of them were first covered with collagen membrane and then with BM-MSCs, PDLSCs, and pre-osteoblasts. The 4(th) defect was filled with collagen membrane and the 5(th) one was served as control. After 4 weeks, histological (quantitative) and histomorphological (qualitative) surveys were performed.

RESULTS

Both cell lineages were positive for CD-90 cell marker, which was specifically related to stem cells. Alizarin red staining was done for showing mineral material. RT-PCR set up for the expression of Cbfa1 gene, BMP4 gene, and PGLAP gene, confirmed osteoblast differentiation. The findings indicated that although PDLSCs and pre-osteoblasts could be used for bone regeneration, the rate of regeneration in BM-MSCs-treated cavities was more significant (p<0.0001).

CONCLUSION

The obtained results are probably attributable to the effective micro-environmental signals caused by different bone types and the rate of cell maturation.

Antibacterial effect of an herbal product persica on porphyromonas gingivalis and aggregatibacter actinomycetemcomitans: an in-vitro study

OBJECTIVE

The plant Salvadora persica is used for oral hygiene in many parts of the world. It has been suggested that it has antibacterial properties, in addition to its ability to mechanically remove plaques. The aim of this study was to assess the antimicrobial activity of the herbal product Persica containing Salvadora persica against periodontopathogens Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans in vitro.

MATERIALS AND METHODS

Fifty patients with moderate and severe periodontitis were recruited. Using paper points, subgingival plaque samples were taken from pockets with attachment loss ≥ 3mm. The samples were subjected to microbial culture to yield P. gingivalis and A. actinomycetemcomitans. The ditch plate method was used for antimicrobial susceptibility testing of the bacteria to Persica compared to chlorhexidine and distilled water. The growth inhibition zones of microorganisms around the ditches were measured in millimeters. The data were analyzed using SPSS 16. Freidman test and Wilcoxon signed ranks test with Bonferroni adjustment were used for analysis of variance with 5% significance level. P<0.05 for main comparisons and P< 0.017 for multiple comparisons were considered statistically significant.

RESULTS

P. gingivalis was sensitive to chlorhexidine and persica. There was a significant difference (P=0.001) between antimicrobial activity of chlorhexidine (mean 28.733mm, SD 5.216) and Persica (mean 16.333mm, SD 5.259) compared to water against P. gingivalis. There was a significant difference (P< 0.001) between the antimicrobial activity of chlorhexidine (24.045mm, SD 3.897) and Persica (0.545mm, SD 2.558) with respect to A. actinomycetemcomitans. There was no significant difference (P=0.317) between the antimicrobial activity of Persica and water against A. actinomycetemcomitans.

CONCLUSION

The herbal product Persica had significant antimicrobial activity against P. gingivalis and negligible antimicrobial activity against A. actinomycetemcomitans compared to 0.2% chlorhexidine.

Comparison of the levels of tumor necrosis factor-α and interleukin-17 in gingival crevicular fluid of patients with peri-implantitis and a control group with healthy implants

Peri-implantitis is a multi-factorial disease involving peri-implant tissues and resulting in therapeutic failure. Inflammatory mediators and cytokines in the Gingival Crevicular Fluid (GCF) have pivotal roles in the disease pathogenesis and could be used for disease monitoring. Therefore, the present study was conducted to compare the GCF levels of TNF-α and IL-17 between patients with peri-implantitis and healthy implants.In this case-control study, 24 patients with peri-implantitis and 18 individuals with healthy implants referring to faculty of dentistry in Tehran University of Medical Sciences were selected. GCF was collected by paper cons number 30. Samples were preserved in PBS -70ºC. TNF-α and IL-17 levels in GCF were determined by ELISA method. Data were analyzed by SPSS software version 13, using descriptive indices and independent t tests.Mean probing depth in peri-implantitis and control groups were 6.2 ± 1.1 and 3.7 ± 1.6 mm respectively. Mean level of IL-17 in patients with peri-implantitis was significantly more than the control group (19.8 ± 16.0 versus 9.3 ± 8.4 pg per site in 40 seconds, p=0.016). Also, mean level of TNF-α in patients with peri-implantitis was more than control group (39.0 ± 3.9 versus 14.5 ± 9.0 pg per site in 40 seconds, p =0.000).The significant higher levels of TNF-α and IL-17 in patients with peri-implantitis compared to control group indicated the pivotal role of these cytokines in peri-implantitis and could be suggested as diagnostic markers and in future possibly for immunomodulatory treatments.

Comparison of 1-periodontal indices and cultural porphyromonas gingivalis colony count in aggressive periodontitis patients treated by scaling and rootplanning with or without metronidazole gel

OBJECTIVE

Systemic antibiotics and locally applied antimicrobial agents have been suggested to enhance clinical parameters. Patients exhibiting aggressive periodontitis in particular benefit from adjunctive antibiotic therapy. The purpose of this investigation was to evaluate the effect of local antibiotic therapy with metronidazole adjunctively to scaling and root planning (SRP) in the treatment of aggressive periodontitis.

MATERIALS AND METHODS

Twenty patients diagnosed with aggressive periodontitis were placed in a spilt mouth design. Microbial specimens were taken from the deepest pocket of the teeth. The sites that had positive results of Porphyromonas gingivalis (P.g) were located randomly to receive SRP treatment in the control group and SRP plus metronidazole gel in the test group. Pocket probing depth (PPD), clinical attachment level (CAL) and bleeding on probing (BOP) parameters and numbers of P.g. colony were taken at baseline, 6 weeks and 12 weeks later. All data were collected and analyzed and tested by Wilcoxon and paired t test.

RESULTS

The case group patients had significantly better results in BOP, PPD and the number of P.g colony count reduction in comparison with the control group (p<0.05). According to the measurements of CAL, the statistical difference was non significant (p>0.05).

CONCLUSION

In non-surgical periodontal treatment of aggressive periodontits adjunctive metronidazole gel therapy has a better effect on the reduction of porphyromonas gingivalis content of pockets.