Abstract

STREIT, G  and  SYKES, LM. Overview of Lithium Disilicate as a restorative material in dentistry. S. Afr. dent. j. [online]. 2022, vol.77, n.8, pp.495-499. ISSN 0375-1562.  http://dx.doi.org/10.17159/2519-0105/2022/v77no8a7.

Lithium disilicate was first introduced to the dental field as an indirect restorative material in 1998. It was marketed under the name IPS Empress 2, and was intended for use with press technology. It was later replaced by modified versions including IPs e.max® Press and IPS e.max® CAD. Newer versions have since emerged, namely Amber Mill GC Initial and CEREC Tesseratwo. The latter has part crystal composition of lithium disilicate, embedded in a glassy zirconia matrix. The CAD version is provided in a meta-silicate state, characterised by 40% platelet-shaped lithium meta-silicate crystals and a glassy matrix that is bluish in colour. To obtain the desired lithium disilicate structure and tooth shades, a process of crystallization is required. This involves firing at 840 °C, for 25 minutes. The resulting glass-ceramic material has the benefit of providing maximum aesthetic translucency along with good fracture resistance of about 2MPa, and mechanical strength of 360MPa. Developments in the all-ceramic dental materials have led to improvements in their physical properties and aesthetic appeal, leading to a substantial increase in their clinical use. This paper present a review of lithium disilicate with particular reference to its chemical composition, aesthetic versatility, and durability for use in crowns, veneers, and implant retained restorations. It also covers the recommended techniques prescribed to ensure predictable bonding and cementation. An electronic literature search on the use of lithium disilicate in dentistry was carried out using EBSCOhost search engine. This included all papers relating to its use for conventional veneers, crowns and bridge work, for CAD/CAM restorations, dentine bonding procedures and luting agents. It covered all papers published in peer reviewed journals from 1988 to 2021. The review indicates that lithium disilicate can be a useful and versatile material in dentistry providing it is handled correctly and the recommended tooth and restoration surface preparations and bonding procedures are carried out. The latter involves tooth etching and silane treatment of the fitting surfaces of restorations prior to cementation to improve adhesion and fracture resistance.

Keywords : Lithium distillate; Li₂O₅Si₂; dentine bonding; Ceramic; e.max®; Microstructure Glass ceramic.

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