Table 2.

Details of second generation IRC

Brand name	Composition	Polymerization	Key points
Artglass Launched in 1995 By Heraeusl-Kulzer	Filler- 70wt% filler of bariumsilicate glass of 0.7µ. Matrix- 30wt% organic resin. Additional to conventional bifunctional molecules, Artglass contains four to six functional groups which provides the opportunity for more double-bond conversions[45].	Photo-cured in a special unit using a xenon stroboscopic light (UniXS, Heraeus/ Kulzer). The system emits 4.5 watts as usable luminous power, while the emission range is between 320 and 500 nanometers. The high intensity is emitted for only 20 milliseconds, followed by 80 milliseconds of darkness.	Can be used to fabricate inlay, onlays and crowns with/without metal substrate (ranges from nickel-chromium to gold-based metals).
		This type of light exposure increases polymerization potential. The short excitation time followed by a longer period of nonexposure allows the already cured resin molecules to partially relax, and more of the nonreactive double-bond carbon groups are made available for reaction[45].	Bonding to the metal substrate is achieved by applying an acrylonitrile copolymer (Kevloc), a flexible copolymer, to the metal surface before placing and curing the restorative material[13].
Belleglass HP introduced by Belle de St. Claire in 1996	Filler-Silanatedmicrohybrid fillers of 0.6 µ. Base and surface composites are available which are used on dentin and enamel respectively. Five different shades of enamel composites are available. The base composite has barium glass fillers (78.7% wt and 65% volume) Surface material has borosilicate fillers which provide enhanced optical characteristics are used (74%wt and 63% volume). Resin matrix of dentin -bis-GMA, whereas, for enamel - a combination of a hydrocarbon saturated methacrylate diurethane of TEGDMA & aliphatic dimethacrylate.	Uses two different curing units. This gives the advantage of incremental buildup and resembles the natural tooth with the hard, translucent, enamel covering the more opaque and softer dentin, able to absorb the stresses. The base composite is light cured, with a conventional light cuirng unit which stabilizes the restoration during build up and reserves unreactive surfaces for bonding. The surface composite is heat cured. The polymerization is carried by heating in an oven at 140oC at 80 psi for 20 minutes. The atmosphere is maintained oxygen free and under nitrogen gas pressure[46].	The reduction in size of the filler improves the polishability and smoothness of the material. Newer composite like “Foundation” has been modified to have a filler diameter of 30 µ in the base composite, which will allow for further reduction in polymerization shrinkage9.
Sinfony Introduced by 3M ESPE	Fillers - ultra-fine glass or glass-ceramic powders Pyrogenic silica is also used as a microfiller. It is a form of amorphous silicon dioxide with a primary particle diameter of < 0.05 µm, produced in an oxy-hydrogen gas flame.	The proprietary system consists of two polymerising units (Visio alpha, Visio beta).the Visio alpha is equipped with a halogen lamp whereas the Visio beta is equipped with four fluorescent tubes. The polymerization wavelength ranges from 400-550nm. The polymerization mode for alpha source is 15 seconds whereas that of beta source is 40°C for 15minutes[47,48] The other non proprietary unit used is Hyper LII which is a high – intensity polymerization unit equipped with two metal halide lamps. The wavelength is in the range of 250-600nm and with an intensity of 150W for 60 seconds[49].	Used for full veneering of fixed and removable prostheses on metal frameworks, for inlays / onlays, individual crowns, glass fibre reinforced bridges and for the customization of prefabricated teeth.
	Matrix-polyfunctional methacrylate monomers.	Polymerization of this material with two different light sources improves the property[50].	Pyrogenic silica has large surface area (up to 350 m2/g) and have therefore a thickening effect. They are used to control the rheological properties of the composite. The microfiller particles can insert themselves into the gaps between the macrofillers.
Targis Launched in 1996 by Ivoclar Vivadent	[ceromer] filler- 77wt%, trimodal and has barium glass of particle size of 1µ. Spheroid silica filler -0.25 µ and colloidal silica – 0.015-0.05 µ. Matrix- conventional monomers.	Targis is coated with glycerin gel (Targis Gel) to prevent formation of oxygen-inhibited surface layer and placed in the curing unit Targis Power (IvoclarVivadent) for the following cycle: light emission in the first 10 min along with increase of temperature to 95°C for 25mins, and cooling for 5 min.	Targis is a veneering composite material. The material can be without framework material, to fabricate adhesive inlays/onlays/ veneers and anterior crowns. In addition, Targis is suitable for veneering metal frameworks.
SR Adoro (Ivoclar Vivadent)	The dentin and enamel materials constitute the main components.
	components of this system include SR Link (to bond to metal frame work), a liner, dentin material, stains, incisal material and Opaquer. SR Link comprises a monomer that contains a highly hydrophobic aliphatic hydrocarbon chain and a phosphoric ester with a methacrylate function. Matrix-of dentin and incisal material consists of UDMA instead of Bis GMA and TEGDMA and the copolymer filler load is about 63% by weight. A copolymer is produced by grinding a microfilled composite into particles of approximately 10-30 µm and later incorporated into inorganic microfillers. Upon polymerization, the copolymers become completely integrated into the composite and a homogeneous composite with a high loading of inorganic microfillers is obtained. The liner has 49% by weight barium glass filler particles.		Targis system has continuously been revised and the, application could now be defined for SR Adoro The phosphoric acid group of the molecule is a strong acid, which reacts with the metal or the metal oxide, forming a phosphate. The phosphates form a passivating layer on the metal surface. After the metal oxide reaction has been completed, the layer becomes very inert. The methacrylate group of the phosphoric acid reacts with the monomer components of SR Link, forming a copolymer and thereby providing a bond to the veneering resin.
Solidex Introduced by Shofu	Light cured indirect ceramic polymer system. Filler -53 vol% of 1µ silicon dioxide and aluminium oxide inorganic fillers[51] and ceramic microfilaments, Matrix-25 wt % co-polymers of multi-functional resins and 22% conventional resins/ light-initiators. It is available as metal primers, cervical, incisal, body, opaque and translucent shades.	The additional light polymerization is done with Solidilite system which is equipped with 4 halogen lamps for fast curing for a curing time of 1~5 minutes at a wavelength of 420-480 nm and temperature of 55 °C. Sublitecuring system is designed for initial or short polymerization during build-up without removing the restoration from the model.
Sculpture plus (Pentron)	Nano-hybrid IRC available as body, incisal, opaceous Body and neck Paste.
	Matrix -difunctionalmethacrylates of PCBisGMA, EBPADMA, BisGMA, UDMA and HDDMA. Fillers-silanated fillers such as barium boro-silicate glass, nano-particulated silica, zirconium silicate, photoinitiator, accelerator, stabilizer and pigments. It also contains a small amount of Al2O3.	Sculpture curing light is an automatic curing light under pressure both prior to and during light cure. The two curing cycles are a build-up cycle and a final cycle when the restoration build-up is complete. It pressurizes with nitrogen gas and automatically runs an 8min cure cycle that includes 5min of pressure, followed by 3 minutes of high intensity light.
TESCERA ATL (BISCO INC)	Filler-The dentin material is a highly filled hybrid (85% by weight, 73% by volume). The body and the incisal material consist of a reinforced microfill (70% by weight). Added to the nanoparticles is a “reinforcement” particle that averages 1-µm in size, compared to the main filler, which is 0.04µm in size. The average particle size for this composite is approximately 50 nanometers (0.05µm). Matrices for the dentin, body and incisal material -Bis- GMA, UDMA, ethoxylatedbis “a” dimethacrylate, and TEGDMA[52]. Incisal Material Matrix utilizes a low Bis- GMA concentration, whereas the dentin and body materials have a higher concentration	Polymerization is done in a light cup and heat cup underwater. The artificial dentin is initially pressurized (60 pounds per square inch [psi]) in a light cup before the light-curing cycle is initiated to eliminate the incorporation of internal voids and bubbles during the incremental build-up process. The light cup contains white reflection beads, which provide support to the working die while reflecting and diffusing light around the chamber and onto the composite surface. Each increment is light cured for 2 minutes. Secondary ppolymerization - heat cup with the restoration submerged in water.	This system maintains a higher density of inorganic ceramic microfillers compared to the earlier-generation direct and indirect systems[54]. These materials have the advantages of both composite resins and porcelains without being confined by the inherent limitations of either. The filler particles are silanated for suitable adhesion to the organic matrix. The presence of these 1-1µm reinforcement particles - acts as a “crack arrester,” while the increased particle concentration of the microfill particles provides improved clinical performance.
		Residual free oxygen in the water is removed by adding an oxygen-scavenger agent. The final restorations are cured using an initial full cycle of pressure (60 psi) with light and heat (peak heat of 130°C and decreasing to approximately 90°C before releasing pressure) for 10 to 13 minutes[53].
Paradigm MZ100 (3M ESPE)	85 wt% ultrafine zirconia-silica ceramic particles that reinforce a highly crosslinked polymeric matrix. The polymer matrix consists of bisGMA and TEGDMA and a ternary initiator system. The particles have a spherical shape, and an average particle size of 0.6 micrometer. This contrasts sharply with milled glass fillers in conventional hybrid composites.	Made from Z100 restorative material under optimized process conditions that assure thorough cure and a high degree of crosslinking. Paradigm MZ100 blocks are made in two cylindrical sizes, 10 and 14; these correspond to the CEREC sizes.	Alternative to porcelain blocks for CEREC restorations.
			The ultrafine zirconia-silica filler particles are synthesized by a patented sol-gel process that results in a unique structure of nanocrystalline zirconia dispersed in amorphous silica.
Vita ZetaLC (Vita Zahnfabrik)	Matrix -Bis GMA, UDMA, TEGDMA Fillers. –multiphase feldspar frits and silicon dioxide (44.3 wt%)	Additional light curing can be done with Dentacolor XS curing unit at circa 40oC at wavelength of 350-500nm	Used for the full and partial veneering of crowns, and as long-term temporary metal-free restorations. nano-sized fillers that ensure high translucency due to natural refraction.
Pearleste E2 (Tokuyama Dental Corp)	Bis-MPEPP, TEGDMA, UDMA, Filler-SilicaZirconia(0.04µ), Silica –titania (0.08µ)	Pearlcure light –high pressure mercury lamp 150W*1, 350-550nm for 120S. Pearlcure heat- heat oven 15 min under atmospheric pressure.
Estenia C&B (Kuraray)	Matrix– UDMA, Filler –alumina ultrafine filler, glass filler (92wt%)	Secondary Light cure – Alpha II for 5 min Secondary heat cure – KL 100at 110oC for 15 minutes[55].
Gradia (GC Corp)	Matrix- UDMA, Filler – silica powder, silicate glass powder, prepolymerised filler (75wt%)[56]	Secondary Light cure – Alpha II for 5 min