Biomaterial Database

Evaluation of curing light distance on resin composite microhardness and polymerization. 2007

Kátia Martins Rode, and Yoshio Kawano, and Miriam Lacalle Turbino

Department of Restorative Dentistry, School of Dentistry of São Paulo, University of São Paulo (USP), São Paulo, Brazil.

This study evaluated the influence of the curing tip distance on cure depth of a resin composite by measuring Vickers microhardness and determining the degree of conversion by using FT-Raman spectroscopy. The light curing units used were halogen (500mW/cm2) and LED (900mW/cm2) at a conventional intensity and an Argon laser at 250mW. The exposure time was 40 seconds for the halogen light, 20 seconds for the LED and 20 and 30 seconds for the Argon laser. The curing tip distances of 0, 3, 6 and 9 mm were used and controlled via the use of metal rings. The composite was placed in a black matrix in one increment at a thickness of 1 mm to 4 mm. The values of microhardness and the degree of conversion were analyzed separately by ANOVA (Analysis of Variance) and Tukey test, with a significance level set at 5%. Correlations were analyzed using the Pearson test. The results obtained conclude that greater tip distances produced a decrease in microhardness and degree of conversion values, while increasing the resin thickness decreased the microhardness and degree of conversion values. A higher correlation between microhardness and the degree of conversion was shown. This study suggests that the current light curing units promote a similar degree of conversion and microhardness, provided that the resin is not thicker than 1 mm and the light source is at a maximum distance of 3 mm from the resin surface.

UI	MeSH Term	Description	Entries
D008027	Light	That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.	Light, Visible,Photoradiation,Radiation, Visible,Visible Radiation,Photoradiations,Radiations, Visible,Visible Light,Visible Radiations
D011140	Polyurethanes	A group of thermoplastic or thermosetting polymers containing polyisocyanate. They are used as ELASTOMERS, as coatings, as fibers and as foams.	Polyisocyanates,Ostamer,Pellethane,Spandex,Ostamers,Pellethanes,Polyisocyanate,Polyurethane,Spandices
D003188	Composite Resins	Synthetic resins, containing an inert filler, that are widely used in dentistry.	Composite Resin,Resin, Composite,Resins, Composite
D006219	Halogens	A family of nonmetallic, generally electronegative, elements that form group 17 (formerly group VIIa) of the periodic table.	Halogen,Group 17 Elements,Elements, Group 17
D006244	Hardness	The mechanical property of material that determines its resistance to force. HARDNESS TESTS measure this property.	Hardnesses
D006245	Hardness Tests	A test to determine the relative HARDNESS of a metal, mineral, or other material according to one of several scales, such as Brinell, Mohs, Rockwell, Vickers, or Shore. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed).	Hardness Test,Test, Hardness,Tests, Hardness
D000180	Acrylic Resins	Polymers of high molecular weight which are derived from acrylic acid, methacrylic acid or other related compounds and are capable of being molded and then hardened to form useful components.	Acrylic Resin,Resin, Acrylic,Resins, Acrylic
D054020	Lasers, Gas	Lasers in which a gas lasing medium is stimulated to emit light by an electric current or high-frequency oscillator.	Argon Ion Lasers,CO2 Lasers,Carbon Dioxide Lasers,Copper Vapor Lasers,Gas Lasers,Gold Vapor Lasers,Helium Lasers,Helium Neon Gas Lasers,Metal Vapor Lasers,Nitrogen Lasers,Xenon Ion Lasers,HeNe Lasers,Lasers, Argon Ion,Lasers, CO2,Lasers, Carbon Dioxide,Lasers, Copper Vapor,Lasers, Gold Vapor,Lasers, Helium,Lasers, Helium Neon Gas,Lasers, Metal Vapor,Lasers, Nitrogen,Lasers, Xenon Ion,Argon Ion Laser,CO2 Laser,Carbon Dioxide Laser,Copper Vapor Laser,Dioxide Laser, Carbon,Dioxide Lasers, Carbon,Gas Laser,Gold Vapor Laser,HeNe Laser,Helium Laser,Ion Laser, Argon,Ion Laser, Xenon,Ion Lasers, Argon,Ion Lasers, Xenon,Laser, Argon Ion,Laser, CO2,Laser, Carbon Dioxide,Laser, Copper Vapor,Laser, Gas,Laser, Gold Vapor,Laser, HeNe,Laser, Helium,Laser, Metal Vapor,Laser, Nitrogen,Laser, Xenon Ion,Lasers, HeNe,Metal Vapor Laser,Nitrogen Laser,Vapor Laser, Copper,Vapor Laser, Gold,Vapor Laser, Metal,Vapor Lasers, Copper,Vapor Lasers, Gold,Vapor Lasers, Metal,Xenon Ion Laser