title: High Frequency Impedance Measurement as a Relevant Tool for Monitoring the Apatitic Cement Setting Reaction.
abstract: This work reports the development of a relevant and general method based on high frequency impedance measurements, for the in situ monitoring of the alpha-tricalcium phosphate (α-TCP) to calcium-deficient hydroxyapatite (CDA) transformation which is the driving force of the hardening processes of some calcium phosphate cements (CPC) used as bone substitutes. The three main steps of the setting reaction are identified in a non invasive way through the variation of dielectric permittivity and dielectric losses. The method is also likely to characterize the effect of the incorporation of additives (i.e, antiosteoporotic bisphosphonate drugs such as Alendronate) in the CPC formulation on the hydration process. It allows not only to confirm the retarding effect of bisphosphonate by an accurate determination of setting times, but also to assess the phenomena taking place whether alendronate is added in the liquid phase or combined to the solid phase of the cement composition. Compared to the conventional Gillmore needle test, the present method offers the advantage of accurate, user-independent, in situ and real-time determination of the initial and final times of the chemical hardening process, which are important parameters when considering surgical applications.
authors: LCPME, Université de Lorraine CNRS UMR 7564, 405 rue de Vandoeuvre 54600 Villers Lès Nancy, France. Electronic address: christelle.despas@lcpme.cn.
authors: Christelle
authors: C
authors: Despas
authors: Graftys SARL Eiffel Park bâtiment D 415 rue Claude Nicolas Ledoux, pôle d'activités d'Aix en Provence, 13854 Aix en Provence cedex 3, France.
authors: Verena
authors: V
authors: Schnitzler
authors: CEISAM, Université de Nantes CNRS UMR 6230, 2 rue de la Houssinière BP92208, 44322 NANTES cedex 03, France.
authors: Pascal
authors: P
authors: Janvier
authors: CEMHTI, CNRS, UPR 3079, 1D Avenue de la Recherche Scientifique, 45071 Orléans Cedex 02, France; Université d'Orléans, Faculté des Sciences, Avenue du Parc Floral, 45067 Orléans Cedex 02, France.
authors: Franck
authors: F
authors: Fayon
authors: CEMHTI, CNRS, UPR 3079, 1D Avenue de la Recherche Scientifique, 45071 Orléans Cedex 02, France; Université d'Orléans, Faculté des Sciences, Avenue du Parc Floral, 45067 Orléans Cedex 02, France.
authors: Dominique
authors: D
authors: Massiot
authors: LIOAD, Université de Nantes INSERM UMR 791 Faculté de chirurgie dentaire BP84215, 44042 NANTES cedex1, France.
authors: Jean-Michel
authors: JM
authors: Bouler
authors: CEISAM, Université de Nantes CNRS UMR 6230, 2 rue de la Houssinière BP92208, 44322 NANTES cedex 03, France.
authors: Bruno
authors: B
authors: Bujoli
authors: LCPME, Université de Lorraine CNRS UMR 7564, 405 rue de Vandoeuvre 54600 Villers Lès Nancy, France.
authors: Alain
authors: A
authors: Walcarius
keywords: Bisphosphonates; Calcium phosphate cement; High frequency impedance; In situ monitoring; initial and final setting times