Knoop Microhardness and FT-Raman Spectroscopic Evaluation of a Resin-Based Dental Material Light-Cured by an Argon Ion Laser and Halogen Lamp: Anin VitroStudy

Abstract

Polymerization with the halogen lamp (G1) attained higher microhardness values than polymerization with the argon laser at power levels of 150 and 200 mW; there was no difference in hardness between the two argon laser groups. The results showed no statistically significant different degrees of conversion for the polymerization of composite samples with the two light sources tested.

Knoop microhardness and FT-Raman evaluation of composite resins: influence of opacity and photoactivation source

“…The 1064-nm line of an aircooled Nd:YAG near-infra-red laser was used to excite the samples. 8,10 The Raman spectra were obtained using 64 scans at a spectral resolution of 4 cm -1 and were analyzed by selecting a spectral region of 1000-2000 cm -1 . The Raman spectrum obtained from the uncured (translucent) FS is represented in Figure 1.…”

“…7 Concerns about these variables have led to several studies recently to determine the degree of conversion (DC) of dental composites. [7][8][9][10][11][12][13][14][15] The sensitivity of molecular vibrational methods, such as infrared spectroscopy (FTIR) and Raman spectroscopy (FT-Raman), offers a direct approach to quantify the ratio of monomers' conversion into polymers; this quantification is accomplished by assessing the specific band positions and by comparing the residual unpolymerized aliphatic C=C stretching band at 1640 cm -1 to the aromatic C=C stretching band at 1610 cm -1 . 8,9,16 Thus, the ratio of double carbon bonds that are converted into single bonds determines the DC of the resin composite.…”

“…[7][8][9][10][11][12][13][14][15] The sensitivity of molecular vibrational methods, such as infrared spectroscopy (FTIR) and Raman spectroscopy (FT-Raman), offers a direct approach to quantify the ratio of monomers' conversion into polymers; this quantification is accomplished by assessing the specific band positions and by comparing the residual unpolymerized aliphatic C=C stretching band at 1640 cm -1 to the aromatic C=C stretching band at 1610 cm -1 . 8,9,16 Thus, the ratio of double carbon bonds that are converted into single bonds determines the DC of the resin composite. 8,[11][12][13]15 On the other hand, the hardness achieved by the polymerized composite is widely used as an indirect method of determining the quality of the light-initiated polymerization process.…”

“…8,9,16 Thus, the ratio of double carbon bonds that are converted into single bonds determines the DC of the resin composite. 8,[11][12][13]15 On the other hand, the hardness achieved by the polymerized composite is widely used as an indirect method of determining the quality of the light-initiated polymerization process. 17 The light that initiates the polymerization may be absorbed or scattered through the body of the resin, jeopardizing the polymerization process.…”

The effect of curing light and chemical catalyst on the degree of conversion of two dual cured resin luting cements

“…The argon ion laser has arisen as an alternative light source for polymerizing resin composites, resin luting cements, and for bleaching procedures [19][20][21]. For camphorquinone-based resins, the activation emits a blue light in the wavelength range 400-500 nm with peak values at about 468 and 480 nm, depending on the monomer formulation, and it has an irradiance at up to 2,000 mW/cm 2 [21][22][23][24].…”