Effects of fibroblast growth factor-2 on cell proliferation of cementoblasts

Extraction Socket Augmentation with Autologous Platelet-Rich Fibrin (PRF): The Rationale for Socket Augmentation

After tooth extraction, the alveolar ridge undergoes a physiological process of remodelling and disuse atrophy. Socket augmentation (SA) has been shown to preserve alveolar bone volume in order to facilitate implant placement and reduce the need for staged grafting at a later date. Although autogenic grafting has been shown to be the gold standard in bone regeneration, it has significant disadvantages. To prevent post-extraction volumetric alterations and alveolar bone resorption occurring, alternative grafting materials, including xenografts, alloplasts, and allografts, have been used successfully in fresh extraction sites. However, these materials act mostly as bio-scaffolds and require a slower integration period of 6-8 months prior to implant placement. Recently, the use of autologous platelet-rich fibrin (PRF) has been advocated alongside socket augmentation as a method of bio-enhancement of healing of soft and hard tissues. PRF contains platelet-derived growth factors, hormones, and bioactive components such as cytokines that have been shown to promote angiogenesis and tissue regeneration during wound healing. The aim of this article is to review the evidence base for the SA technique Clinical benefits of SA will be discussed with a reference to two cases. Therefore, this narrative review will discuss the post-extraction bone changes, the importance of SA, and the bio-enhancement role of PRF in the management of extraction site defects when the alternative technique of immediate implant placement is not possible or contraindicated.

Nuclear factor-kappa B (NF-κB) decoy oligodeoxynucleotide-loaded poly lactic-co-glycolic acid (PLGA) nanospheres promote periodontal tissue healing after tooth replantation in rats

BACKGROUND

Excessive inflammation in the periodontal tissue after tooth replantation can lead to inflammatory root resorption and interrupt periodontal tissue regeneration. We tested the hypothesis that NF-κB decoy oligodeoxynucleotide-loaded poly lactic-co-glycolic acid nanospheres (NF-PLGA) inhibit excessive inflammation and promote healing of periodontal tissue after replantation in rats.

METHODS

The upper right incisors of rats were extracted, immersed in different specific solutions, and replanted. The rats were euthanized at 7, 14, and 28 days after replantation. Morphological evaluation with micro-CT and histological assessment with hematoxylin and eosin and tartrate-resistant acid phosphatase (TRAP) staining was performed. Additionally, we examined the expression of interleukin (IL)-1β, IL-6, transforming growth factor-β1 (TGF-β1), and fibroblast growth factor-2 (FGF-2) in the periodontal ligament (PDL) by performing immunohistological assessment.

RESULTS

The NF-PLGA group showed significantly greater dental root thickness than the other experimental groups. Root resorption was not observed after the application of NF-PLGA on day 7. The application of NF-PLGA also resulted in a significantly lower number of TRAP-positive osteoclasts on days 7 and 14 after replantation. Significantly lower expression of IL-1β and IL-6 and higher expression of TGF-β1 and FGF-2 were observed under the application of NF-PLGA in the PDL.

CONCLUSIONS

NF-PLGA promoted the healing process by inhibiting the initial excessive inflammatory response in the PDL, preventing root resorption, and promoting periodontal tissue regeneration. The findings also suggested that the PLGA nanospheres-mediated transfection of the decoy oligodeoxynucleotides can be useful for the clinical application of replanted tooth root surfaces. This article is protected by copyright. All rights reserved.

Assessment of Human Gingival Fibroblast Proliferation after Laser Stimulation In Vitro Using Different Laser Types and Wavelengths (1064, 980, 635, 450, and 405 nm)-Preliminary Report

PURPOSE

to assess the effect of photobiomodulation (PBM) on human gingival fibroblast proliferation.

METHODS

The study was conducted using the primary cell cultures of human fibroblasts collected from systemically healthy donors. Three different laser types, Nd:YAG (1064 nm), infrared diode laser (980 nm), and prototype led laser emitting 405, 450, and 635 nm were used to irradiate the fibroblasts. Due to the patented structure of that laser, it was possible to irradiate fibroblasts with a beam combining two or three wavelengths. The energy density was 3 J/cm2, 25 J/cm2, 64 J/cm2. The viability and proliferation of cells were determined using the (Thiazolyl Blue Tetrazolium Blue) (MTT) test conducted 24, 48, and 72 h after laser irradiation.

RESULTS

The highest percentage of mitochondrial activity (MA = 122.1%) was observed in the group irradiated with the 635 nm laser, with an energy density of 64 J/cm2 after 48 h. The lowest percentage of MA (94.0%) was observed in the group simultaneously irradiated with three wavelengths (405 + 450 + 635 nm). The use of the 405 nm laser at 25 J/cm2 gave similar results to the 635 nm laser.

CONCLUSIONS

The application of the 635 nm and 405 nm irradiation caused a statistically significant increase in the proliferation of gingival fibroblasts.

Combined effects of fibroblast growth factor 2 and dexamethasone on differentiation of human cementoblasts

Fibroblast growth factor 2 (FGF-2) is known to play a pivotal role in bone remodeling and osteogenesis. Dexamethasone is a potent modulator of osteogenic differentiation and can increase the bone formation capacity of cementoblasts. However, the combined effects of FGF-2 and dexamethasone on cementoblasts and the way they regulate the activities of cementoblasts have not been fully understood. The aim of this study was to clarify and investigate the effects of the combination of FGF-2 and dexamethasone on growth and differentiation in human cementoblasts and to determine the underlying mechanism. A series of experiments including MTT, alkaline phosphatase (ALP) activity, alizarin red staining, RT-PCR, and Western blot were carried out to evaluate the proliferation and differentiation of cementoblasts. In addition, the changes of Wnt signaling pathway molecules were checked to analyze the possible mechanism. Compared to the treatment of cementoblasts with either FGF 2 or dexamethasone alone, the combination of FGF-2 and dexamethasone synergistically increased cell proliferation, ALP activity, nodule formation, and expression of differentiation markers. In addition, FGF 2 and dexamethasone enhanced expression of Wnt3a, Runx2, β-catenin, and p-GSK-3β, all of which were inhibited by DKK1. Taken together, FGF-2 and dexamethasone act synergistically, enhancing each other's ability to stimulate cementoblast growth and differentiation via Wnt signaling pathways. These results support the therapeutic potential of a combination strategy for facilitating cementogenesis and aiding periodontal regeneration.