Suitability evaluation of sol–gel derived Si-substituted hydroxyapatite for dental and maxillofacial applications through in vitro osteoblasts response

Balamurugan, A.; Rebelo, A.H.S.; Lemos, A.F.; Rocha, J.H.G.; Ventura, J.M.G.; Ferreira, J.M.F.

doi:10.1016/j.dental.2008.02.017

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Volume 24, Issue 10 , Pages 1374-1380, October 2008

Suitability evaluation of sol–gel derived Si-substituted hydroxyapatite for dental and maxillofacial applications through in vitro osteoblasts response

A. Balamurugan
- Department of Ceramics and Glass Engineering, University of Aveiro, CICECO, 3810-193 Aveiro, Portugal
A.H.S. Rebelo
- Department of Ceramics and Glass Engineering, University of Aveiro, CICECO, 3810-193 Aveiro, Portugal
A.F. Lemos
- Department of Ceramics and Glass Engineering, University of Aveiro, CICECO, 3810-193 Aveiro, Portugal
J.H.G. Rocha
- Agoramat, Produção de Materiais Cerâmicos, Lda., Rua Sacadura Cabral 3-A, 3830-719 Gafanha da Nazaré, Portugal
J.M.G. Ventura
- Department of Ceramics and Glass Engineering, University of Aveiro, CICECO, 3810-193 Aveiro, Portugal
J.M.F. Ferreira
- Department of Ceramics and Glass Engineering, University of Aveiro, CICECO, 3810-193 Aveiro, Portugal
- Corresponding author. Tel.: +351 234 370242; fax: +351 234 425300.

Received 22 March 2007; accepted 11 February 2008.

Abstract

Si-hydroxyapatite (Si-HAP) has been used in orthopedic, dental, and maxillofacial surgery as a bone substitute.

Objective

The aim of this investigation was to study the effect of Si substitution into the hydroxyapatite matrices and evaluate the biocompatibility effects of Si-HAP material in vitro with human osteoblasts.

Methods

Silicon-substituted hydroxyapatite (Si-HAP) bioceramic materials were prepared by incorporating small amounts of silicon into the structure of hydroxyapatite [Ca₁₀(PO₄)₆(OH)₂, HAP] through a sol–gel method. A series of silicon substitutions ranging from 0, 1, 3 and 5mol%, which are comparable to the measured silicon contents in natural bone, were performed.

Results

Single-phase Si-HAP was obtained upon calcining the as-prepared powders up to 800°C since no secondary phases, such as tricalcium phosphate (TCP), tetracalcium phosphate (TeCP) or calcium oxide (CaO), were identified by X-ray diffraction analysis. The effects of silicon-substituted hydroxyapatite (Si-HAP) materials towards the responses of human osteoblast-like (HOB) cells were investigated and compared with pure hydroxyapatite.

Significance

The Si-HAP indicated a significant increase in cell growth density with culture time irrespective of the amount of Si substituted in HAP. A high Si content (5mol%) appears to promote rapid bone mineralization, since large amount of calcium phosphate minerals started to develop across the ECM by day 31 for a sample containing 5mol% Si. On the other hand, a high Si content may result in fast dissolution of the material, owing to a decrease of HAP crystallite size, which might not be ideal for cell attachment for prolonged time periods. An optimum level of Si appears to exist at 3mol%, which balances these effects.

Keywords: Hydroxyapatite, Silicon, Sol–gel, Osteoblast, Biocompatibility