fibrin and Dentin--Secondary

To evaluate the use of platelet-rich fibrin (PRF) in the regenerative therapy of immature canine permanent teeth.. Eight immature premolars of beagle dogs were pulp extracted and cleaned with irrigation, then divided into two groups of empty root canals and those filled with a PRF clot. All of the eight premolars were sealed with mineral trioxide aggregate and glass ionomer cement. Two premolars were left naturally grown as a positive control. The root development was assessed radiographically and histologically after 12 weeks.. The radiological findings showed greater increases in the thickness of lateral dentinal wall in the PRF group than in the vacant group. Histologically, dental-associated mineral tissue, connective tissue, and bone-like mineral tissue grew into the root canals independent of PRF clot use. The PRF was able to increase the thickness of dental-associated mineral tissue. However, the vital tissue differed from the pulp dentin complex.. Our study demonstrated the feasibility of using PRF-mediated regenerative therapy in pulpless immature teeth for improving tissue repair.

Topics: Aluminum Compounds; Animals; Apexification; Bicuspid; Blood Platelets; Calcification, Physiologic; Calcium Compounds; Connective Tissue; Dental Pulp Cavity; Dentin; Dentin, Secondary; Dogs; Drug Combinations; Fibrin; Glass Ionomer Cements; Male; Oxides; Regeneration; Root Canal Filling Materials; Root Canal Irrigants; Root Canal Preparation; Silicates; Therapeutic Irrigation; Tooth Apex

Platelet-rich fibrin (PRF) by Choukroun's technique is derived from an autogenous preparation of concentrated platelets without any manipulation. When delicately pressed between 2 gauzes, the PRF clot becomes a strong membrane with high potential in clinical application. However, the effect of PRF on dental pulp cells (DPCs) remains to be elucidated. This study was to determine the biological effects of PRF on DPCs.. PRF samples were obtained from 6 healthy volunteers. Human DPCs were derived from healthy individuals undergoing extraction for third molars. Cell proliferation resulting from PRF was evaluated by colorimetric assay. Western blot was used to evaluate the expression of osteoprotegerin (OPG). Alkaline phosphatase (ALP) activity was examined by substrate assay.. PRF did not interfere with cell viability of DPCs (P > .05). DPCs were observed to attach at the edges of PRF by phase-contrast microscopy. PRF was found to increase DPC proliferation during 5-day incubation period (P < .05). PRF was found to increase OPG expression in a time-dependent manner (P < .05). ALP activity was also significantly up-regulated by PRF (P < .05).. PRF was demonstrated to stimulate cell proliferation and differentiation of DPCs by up-regulating OPG and ALP expression. These findings might serve as a basis for preclinical studies that address the role of PRF in reparative dentin formation.

Topics: Alkaline Phosphatase; Analysis of Variance; Blood Platelets; Blotting, Western; Cell Differentiation; Cell Proliferation; Cell Survival; Cells, Cultured; Colorimetry; Dental Pulp; Dentin, Secondary; Fibrin; Humans; Osteoblasts; Osteoprotegerin; Statistics, Nonparametric; Up-Regulation

The purpose of this study was to examine changes in distribution of fibrinogen/fibrin and fibronectin in the dentin-pulp complex after cavity preparation.. Class V cavity preparations were prepared on maxillary first molars of 12 rats. The dentin and pulps were observed histologically and immunohistochemically for fibrinogen and fibronectin at 6 hours and 1, 2, and 3 days after the preparation.. At 6 hours and 1 day after cavity preparation, positive staining for fibrinogen was noted in the exudative lesion and in the dentinal tubules under the cavity preparation. Fibronectin staining in the exudate showed a pattern with close similarity to the fibrinogen staining. At 3 days after cavity preparation, the irregularly shaped predentin under the cavity preparation showed strong positive staining for fibronectin.. Fibrinogen/fibrin and fibronectin are present during the healing process of the dentin-pulp complex after cavity preparation.

Topics: Animals; Dental Cavity Preparation; Dental Pulp; Dentin; Dentin, Secondary; Dentinal Fluid; Fibrin; Fibrinogen; Fibronectins; Immunohistochemistry; Odontoblasts; Rats; Rats, Sprague-Dawley

The fine structure of tissue changes during the first 14 days following pulp exposure and capping with a hard setting Ca(OH)2 cement has been studied. The early changes included hemorrhage and moderate inflammation which were largely resolved during the first week. During the second week differentiation of cells occurred at the wound surface. These cells had the characteristic features of odontoblasts and formed a predentin-like collagen matrix. The capping material was closely adapted to cellular structures at the wound surface or to the predentin-like matrix at all observation periods. Dentin fragments displaced into the pulp tissue during cavity preparation, acted as sites for pulp stone formation.

Topics: Animals; Calcium Hydroxide; Collagen; Dental Pulp; Dental Pulp Capping; Dental Pulp Exposure; Dentin, Secondary; Fibrin; Intercellular Junctions; Macaca mulatta; Macrophages; Odontoblasts; Organelles; Pulpitis; Wound Healing