Tesis doctoral de Mohammad Hamdan Ali Al-khraisat
«the use of bone grafts in the repair of defects in dentistry has a long history of success, primarily with the use of autologous bone. With increasing technologic advances, researchers have been able to broaden the spectrum of grafting materials to a llografts, xenografts, and synthetic materials. Osteoconductive and biocompatible calcium phosphate bone substitutes are widely used for the treatment of osseous defects caused by infection, tumors and trauma. A bone graft to function adequately must have a sufficient strength to withstand applied stresses and good cohesion, especially, when used in highly blood-perfused regions. Calcium phosphate cements are being used as bone graft substitutes. They are classified into hydroxyapatite and dical cium phosphate dihydrate (dcpd or brushite) cements according to their final product. These cements are too weak to be used in load bearing areas, even though hydroxyapatite cements are stronger than brushite cements. However, brushite is metastable under physiological conditions and, in vivo studies have shown that brushite cement is highly resorbable. Brushite crystal-growth inhibition results in smaller crystals size allowing them to pack closely together and improving brushite cement mechani cal properties. Furthermore, increasing brushite cement density improves the cement mechanical properties by reducing the cement porosity that is inversely proportional to the cement strength. This can be achieved by increasing the conversion of ?-Tr icalcium phosphate (?-Tcp) to brushite during the cement setting reaction. different in vivo studies demonstrated that brushite cements are biocompatible, bioresorbable and osteoconductive. However, the degradation of brushite cements has been scar cely studied even though it may be of great concern for clinical applications in highly blood-perfused regions. The objective of this work is to elucidate factors that determine brushite cement surface disintegration. For that, brushite cements were modified using in their preparation different aqueous solutions of phosphoric, glycolic, tartaric and citric acids in concentrations that were reported to improve the cement properties. Two viscosity-enhancing polysaccharides, chondroitin 4 sulfate a nd hyaluronic acid were also assayed. Thereafter, pre- and set cement samples were immersed in distilled water for 24 hours. Thenceforth, cement-solid weight loss, microstructure, liquid phase viscosity, mean size and zeta potential of the released p»
Datos académicos de la tesis doctoral «Bioactividad de cementos de fosfatos cálcicos sustituidos con estroncio y su aplicación en regeneración ósea.«
- Título de la tesis: Bioactividad de cementos de fosfatos cálcicos sustituidos con estroncio y su aplicación en regeneración ósea.
- Autor: Mohammad Hamdan Ali Al-khraisat
- Universidad: Complutense de Madrid
- Fecha de lectura de la tesis: 21/10/2008
Dirección y tribunal
- Director de la tesis
- Enrique López Cabarcos
- Tribunal
- Presidente del tribunal: María no Sanz alonso
- Mª lorenza Escudero rincón (vocal)
- Antonio Jesús Salinas sanchez (vocal)
- uwe Gbureck (vocal)