Inducing bioactivity of dental ceramic/bioactive glass composites by Nd:YAG laser.
Aims of this study were to investigate the optimal conditions of laser irradiation of a novel Bioactive Glass/Dental Ceramic-BP67 composite for acceleration of hydroxyapatite-HA formation and to assess cellular responses on the precipitated HA region.



BP67 (Bioactive Glass: 33.3%, Dental Ceramic: 66.7%) was fabricated by the sol-gel method. A laser assisted biomimetic-LAB process was applied to BP67 sintered specimens immersed in 1.5-times concentrated simulated body fluid-1.5×-SBF. The effect of various energy densities of pulsed nanosecond Nd-YAG (1064nm) laser and irradiation exposure times (30min, 1 and 3h) were evaluated for HA precipitation. The HA film was characterized by FTIR, XRD, SEM and micro Raman techniques. ICP-AES was used for revealing changes in chemical composition of the 1.5×-SBF during irradiation. Cell viability and morphological characteristics of periodontal ligament fibroblasts-PDLFs, human gingival fibroblasts-HGFs and SAOS-2 osteoblasts on the HA surface were evaluated by MTT assays and SEM.



At optimal energy fluence of 1.52J/cm2and irradiation time for 3h followed by immersion in 1.5×-SBF at 60°C, a dense HA layer was formed on laser-irradiated BP67 within 7 days. The resulting HA film was tightly bonded to the underlying substrate and had mineral composition similar to cementum. MTT assay showed a consistent reduction of cell proliferation on the HA layer in comparison to conventional control ceramic and BP67 for all 3 cell lines studied.



These findings suggest LAB is an effective method for acceleration of HA formation on materials with low bioactivity, while cellular responses need further investigation.
Department of Fixed Prosthesis and Implant Prosthodontics, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece.
Anastasia
A
Beketova
Department of Electrical Engineering, Technological Educational Institute of Western Macedonia, Koila, 50100 Kozani, Greece.
Nikolaos
N
Poulakis
Department of Fixed Prosthesis and Implant Prosthodontics, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece.
Athina
A
Bakopoulou
Physics Department, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece.
Triantafillia
T
Zorba
School of Geology, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece.
Lambrini
L
Papadopoulou
Department of Chemical Engineering, School of Engineering, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece.
Dimitrios
D
Christofilos
School of Geology, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece.
Nikolaos
N
Kantiranis
Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece.
George A
GA
Zachariadis
Department of Fixed Prosthesis and Implant Prosthodontics, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece.
Eleana
E
Kontonasaki
Department of Chemical Engineering, School of Engineering, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece.
Gerasimos A
GA
Kourouklis
Physics Department, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece.
Konstantinos M
KM
Paraskevopoulos
Department of Fixed Prosthesis and Implant Prosthodontics, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece. Electronic address: pkoidis@dent.auth.gr.
Petros
P
Koidis
D002516:Ceramics; D003776:Dental Porcelain; D017886:Durapatite; D005898:Glass; D006801:Humans; D053844:Lasers, Solid-State; D008855:Microscopy, Electron, Scanning; D014961:X-Ray Diffraction
D003776:Dental Porcelain; D017886:Durapatite
Bioceramic composites; Biomimetic process; Human gingival fibroblasts (hGFs); Human osteosarcoma osteoblast-like cells (SAOS-2); Hydroxyapatite; Laser assisted biomimetic (LAB) process; Periodontal ligament fibroblasts (PDLFs)