The Role of Leukocyte and Platelet-Rich Fibrin in Enhancing the Healing of Extraction Sockets: An Overview of the Literature

Introduction: Leukocyte and platelet-rich fibrin (L-PRF) is an emerging material in dentistry, however, there are controversies surrounding its effectiveness. Despite the amount of literature available, debates regarding its effect continue. This review aims to summarize and clarify the data surrounding the use of L-PRF in promoting the healing of extraction sockets, which may offer a better outcome for future treatments. Purpose: The purpose of this review is to evaluate the current literature on the use of L-PRF in promoting the healing of extraction sockets, and to provide a comprehensive overview of the available evidence. Methods: A comprehensive computer-based search of databases such as PubMed, Medline, and Cochrane Library was conducted. Results: The results of this review suggest that L-PRF has shown promise in promoting early healing of extraction sockets, but the evidence for its effectiveness over a longer period is limited. Conclusion: Although L-PRF has shown promising results in the early healing periods, its effectiveness over a longer healing period cannot be confirmed based on the available data. More clinical trials with standardized protocols and consistent measurement methods are needed to establish the role of L-PRF in enhancing the healing of extraction sockets.

The Effect of Simvastatin on mRNA Expression of Transforming Growth Factor-β1,Bone Morphogenetic Protein-2 and Vascular Endothelial Growth Factor in Tooth Extraction Socket

Aim To determine the effect of local simvastatin application on the mRNA expression level of transforming growth factor-β1 （TGF-β1）, bone morphogenetic protein-2 （BMP-2） and vascular endothelial growth factor （VEGF） in the tooth sockets of rat. Methodology Forty-eight male Wistar rats were randomly divided into experimental and control groups （n=24）. Polylactic acid/polyglycolic acid copolymer carriers, with or without simvastatin, were implanted into extraction sockets of right mandibular incisors. The expression of TGF-β1, BMP-2 and VEGF mRNA was determined by in situ hybridization in the tooth extraction socket at five days, one week, two weeks and four weeks after implantation. Results The fusiform stroma cells in the tooth extraction socket began to express TGF-β1, BMP-2 and VEGF mRNA in both experimental and control groups from one week after tooth extraction until the end of experiment. The expression of TGF-131 and BMP-2 mRNA in the experimental group was significantly up-regulated after one, two and four weeks, and expression of VEGF mRNA was significantly increased after one and two weeks compared with that in the control group. Conclusion The findings indicate that local administration of simvastatin can influence alveolar bone remodeling by regulating the expression of a school of growth factors which are crucial to osteogenesis in the tooth extraction socket.

Design of Collagen-Based Sponge Device for Use in Oral Surgery

This study aims to develop various types of collagen devices for use in oral surgery. The targets are the sheet-shaped sponges to cover mucosal defect wounds (product-1) and gingival defect wounds (product-2) and the cylindrical sponge to fill tooth extraction sockets (product-3). The sheet-shaped sponges were manufactured by freeze-vacuum drying the aqueous solution of collagen (Col) and heat-denatured collagen (Col’) at a composition ratio of 2/1, 1/1 or 1/2. Both surfaces of the sheet-shaped sponge were treated by ultraviolet (UV) irradiation for 5, 10 or 15 minutes to introduce intermolecular crosslinks between collagen molecules. The elution behavior of each collagen sponge was investigated by immersing the sponge in water for a predetermined time and then by measuring the weight change. The collagen sponge composed of Col and Col’ with a composition ratio of 2/1 that was treated by UV irradiation for 15 minutes showed very slow elution properties. This sheet-shaped sponge is the top candidate for product-1. The collagen sponge composed of Col and Col’ with a composition ratio of 2/1 that was treated by UV irradiation for 5 minutes showed slightly fast elution properties. This sheet-shaped sponge is the top candidate for product-2. Next, the cylindrical sponge was manufactured by freeze-vacuum drying the aqueous solution of Col and Col’ at a composition ratio of 2/1. Both sides of the cylindrical sponge were treated by UV irradiation for 15 minutes. This sponge showed initially fast elution properties and subsequent very slow elution properties. This cylindrical sponge is a good candidate for product-3. As a basic design, the sheet-shaped sponge and the cylindrical sponge should be biodegraded and absorbed by the time new tissue formation is completed.

Comparison of bone regeneration in alveolar bone of dogs on mineralized collagen grafts with two composition ratios of nanohydroxyapatite and collagen

To study the effect of two composition ratios of nano-hydroxyapatite and collagen(NHAC)composites on repairing alveolar bone defect of dogs.Eighteen healthy adult dogs were randomly divided into three groups.Two kinds of the NHAC composites were prepared according to the constituent ratios of 3:7 and 5:5;immediately after extraction of the mandibular second premolars,each kind of the NHAC composite was implanted into extraction socket,respectively:Group I,nHA/Col紏3:7;Group II,nHA/Col紏5:5 and Group III,blank control group.The bone-repairing ability of the two grafts was separately analyzed by morphometric measurement,X-ray tomography examination and biomechanical analysis at 1st,3rd and 6th month post-surgical,respectively.The NHAC composites were absorbed gradually after implanting into alveolar bone defect and were replaced by new bone.The ratios of new bone formation of Group I was significantly higher than that of Group II after 3 months(P<0.05).The structure and bioactive performance can be improved when the ratio between the collagen and the hydroxyapatite was reasonable,and the repairing ability and effect in extraction sockets are obviously better.