Transparent magnesium aluminate spinel: a prospective biomaterial for esthetic orthodontic brackets

J Mater Sci Mater Med. 2014 Nov;25(11):2591-9. doi: 10.1007/s10856-014-5268-3. Epub 2014 Jul 16.

Abstract

Adult orthodontics is recently gaining popularity due to its importance in esthetics, oral and general health. However, none of the currently available alumina or zirconia based ceramic orthodontic brackets meet the esthetic demands of adult patients. Inherent hexagonal lattice structure and associated birefringence limits the visible light transmission in polycrystalline alumina and make them appear white and non transparent. Hence focus of the present study was to assess the feasibility of using magnesium aluminate (MgAl2O4) spinel; a member of the transparent ceramic family for esthetic orthodontic brackets. Transparent spinel specimens were developed from commercially available white spinel powder through colloidal shaping followed by pressureless sintering and hot isostatic pressing at optimum conditions of temperature and pressure. Samples were characterized for chemical composition, phases, density, hardness, flexural strength, fracture toughness and optical transmission. Biocompatibility was evaluated with in-vitro cell line experiments for cytotoxicity, apoptosis and genotoxicity. Results showed that transparent spinel samples had requisite physico-chemical, mechanical, optical and excellent biocompatibility for fabricating orthodontic brackets. Transparent spinel developed through this method demonstrated its possibility as a prospective biomaterial for developing esthetic orthodontic brackets.

MeSH terms

  • Aluminum Compounds / chemistry
  • Aluminum Compounds / pharmacology
  • Aluminum Oxide / chemistry*
  • Aluminum Oxide / pharmacology*
  • Apoptosis / drug effects
  • Cell Survival / drug effects
  • Dental Materials / chemical synthesis*
  • Dental Materials / pharmacology*
  • Esthetics, Dental*
  • HEK293 Cells
  • Hardness
  • Humans
  • Magnesium Compounds / chemistry
  • Magnesium Compounds / pharmacology
  • Magnesium Oxide / chemistry*
  • Magnesium Oxide / pharmacology*
  • Materials Testing
  • Orthodontic Brackets*
  • Refractometry
  • Surface Properties
  • Tensile Strength

Substances

  • Aluminum Compounds
  • Dental Materials
  • Magnesium Compounds
  • spinell
  • aluminum magnesium oxide
  • Magnesium Oxide
  • Aluminum Oxide