In vitro effects of Choukroun's platelet-rich fibrin conditioned medium on 3 different cell lines implicated in dental implantology.

OBJECTIVE: The aim of this work was to determine the relevance of Choukroun's platelet-rich fibrin (PRF) in dental implantology by determining the in vitro effects of soluble factors released by PRF clot. We used 3 different cell lines implicated in dental implantology: osteoblast, keratinocyte, and fibroblast. METHODS: Cellular viability, cell proliferation, and gene expression were analyzed using PRF conditioned medium. Three different cells lines were used: SaOS2 (osteoblast), MRC5 (fibroblast), and KB (epithelial cell). RESULTS: The sulforhodamine B assay showed a significant increase in cell number for the undiluted and 1:3 diluted conditioned medium after 24 and 48 hours. There was no effect for the 1:9 dilution. Cell cycle analysis by flow cytometry confirmed the viability test results. After 48 hours, PRF conditioned medium induced gene expression in osteoblasts. Expression of osteopontin and osteocalcin, late osteogenic markers, was observed using reverse transcriptase-polymerase chain reaction (RT-PCR). CONCLUSIONS: This study establishes a model to evaluate, in vitro, the effects of soluble growth factors released by PRF clot. Our work confirmed PRF is useful in stimulating tissue healing and bone regeneration. This work should recommend Choukroun's PRF in numerous implantology clinical applications.

Management options for dental extraction in hemophiliacs: a study of 55 extractions (2000-2002).

OBJECTIVE: Dental extraction in hemophiliacs is associated with a high risk of bleeding. It requires a multidisciplinary approach and stringent protocol. The current trend is to simplify these protocols. In this study we review the efficacy of a protocol using systemic treatment--factors/dihydro-D-arginine vasopressin (DDAVP)--and simplified local hemostatic measures to control bleeding, to limit patient discomfort, and to minimize hospital length of stay. STUDY DESIGN: This retrospective study of 55 dental extractions was performed during 19 interventions in 16 patients with hemophilia A or B to assess the efficacy of a protocol combining general management via the injection of factor concentrates or DDAVP and local hemostasis using biological glue and gelatin packing. Compressive, hemostatic splints, which have been in use by some for many years, are replaced by intermittent tranexamic acid compression during the first 3 days after surgery. RESULTS: We recorded 6 instances of postsurgical bleeding, 4 of which occurred after the compression period. In 2 cases repetition of the local hemostasic measures was required along with the injection of an antihemophilic factor concentrate. In the other 4 cases, the patients' condition reverted to normal following injection of the factor concentrate and the reapplication of the compression. CONCLUSION: The adopted protocol produced a reliable outcome, limiting the duration of the hospital stay to 24 hours in most cases, and improving postsurgical comfort thanks to a combination of systemic treatment and local hemostasic measures including intermittent tranexamic acid compression.

Development of a three-dimensional model for rapid evaluation of bone substitutes in vitro: effect of the 45S5 bioglass.

The evaluation of innovative bone substitutes requires the development of an optimal model close to physiological conditions. An interesting alternative is the use of an immortalized cell line to construct multicellular spheroids, that is, three-dimensional (3D) cultures. In this study, a modified hanging drops method has resulted in the generation of spheroids with a well-established human fetal osteoblasts line (hFOB 1.19), and tests have been focused on the effect of 45S5 bioglass ionic dissolution products in comparison with two-dimensional (2D) cultures. Depending on cell culture type, quantitative analysis (cell proliferation, viability/cytotoxicity, and cellular cycle) and qualitative analysis (electron microscopy and genes expression) showed a differential effect. Cell proliferation was enhanced in 2D-conditioned cultures in accordance with literature data, but decreased in 3D cultures submitted to the same conditions, without change of gene expression patterns. The decrease of cell proliferation, observed in conditioned spheroids, appears to be in agreement with clinical observations showing the insufficiency of commercially available bioglasses for bone repairing within nonbearing sites, such as periodontal defects or small bone filling, in general. Therefore, we suggest that this model could be adapted to the screening of innovative bioactive materials by laboratory techniques already available and extended monitoring of their bioactivity.