Curing depth of a composite veneering material polymerized with seven different laboratory photo‐curing units

Abstract

Properties of laboratory-cured composite materials are affected by the type of activation system as well as by the photo-curing unit light source. This study examined curing depth of a composite veneering material polymerized by means of various photo-curing units with the aim of evaluating the curing performance of the light sources. A microfilled composite material designed for prosthetic veneer was cured with seven photo-curing units. The light sources of the units were halogen/fluorescent, xenon, metal halide, fluorescent, halogen, halogen and mercury lamps. Exposure periods were 20, 30, 60 and 90 s. The curing depth of the material was determined using the method described by the International Organization for Standardization (ISO 4049). Two-factor analysis of variance revealed that the depth of cure was influenced both by the type of curing unit and by the exposure period (P = 0.0001). Among the seven photo-curing units, a metal halide curing unit consistently exhibited the greatest depth of cure. For all units, longer exposure increased the depth of cure.

Influence of laboratory light sources on the wear characteristics of indirect composites

“…For both materials, polymerization with Hyper LII -which had the highest light intensity-resulted in the lowest wear; conversely, polymerization with Labolight LV-II resulted in the highest wear. Results obtained in this study agreed with previous reports in that wear-resistant materials showed excellent mechanical properties 8,13,15) , and that the mechanical properties and wear resistance of light-polymerized composite materials could be considerably improved by application of high-intensity light sources 17,28,29) . Apart from the effect of high-intensity light sources, we speculated that improvement in the double bond conversion of monomers in the composite matrix played a role in improving the wear resistance and properties of composite materials.…”

“…For Hyper LII unit (Toho Dental Products, Saitama, Japan) 28) , two metal halide lamps were used for the light source; for -Light II unit (J. Morita Corp., Suita, Japan) 29) , a halogen lamp and two fluorescent tubes were used; for Labolight LV-II unit (GC Corp.) 29) , three fluorescent tubes were used. Table 1 summarizes the details concerning the composite materials, casting alloy, and polymerization units.…”

“…Similarly, indirect composites have also demonstrated improved characteristics -through clinical evaluations-when used as prosthetic veneering agents [21][22][23][24][25][26][27] . Unlike casting alloys and ceramic materials, the post-polymerization properties of indirect composites vary considerably depending on the conditions under which the matrix monomers are polymerized -namely, type of laboratory polymerization unit, light intensity, distance between light source and material surface, exposure duration, and post-cure heat treatment [17][18][19][20]28,29) . Although the wear of indirect composites has been extensively evaluated [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] , information on the wear characteristics of indirect composites in relation to laboratory polymerization conditions remains scarce.…”

Depth of cure and hardness of an indirect composite polymerized with three laboratory curing units

“…In addition, a metal halide lamp that emits both ultraviolet and visible light is one of the new extra-oral light sources with high lightintensity. The effectiveness of the metal halide unit in polymerization of light-activated material has been Depth of cure and hardness of an indirect composite polymerized with three laboratory curing units Naomi Tanoue 1) , Mahoko Murakami 2) , Hiroyasu Koizumi 3,4) , Mitsuru Atsuta 5) and Hideo Matsumura Original demonstrated by many researchers (4)(5)(6)(7)(8).…”

“…Tanoue et al (9) examined certain properties of indirect composites polymerized with different light sources, and reported that hardness and water solubility were strongly influenced by the type of laboratory light-polymerizing units. The role of the laboratory light-polymerizing unit has also been indicated for improvement of curing depth and wear resistance (5,10).…”