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Pianelli C, Devaux J, Bebelman S, Leloup G. The micro-Raman spectroscopy, a useful tool to determine the degree of conversion of light-activated composite resins. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1999; 48:675-81. [PMID: 10490681 DOI: 10.1002/(sici)1097-4636(1999)48:5<675::aid-jbm11>3.0.co;2-p] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Light-activated composites are now among the most popular dental restorative materials. Nevertheless, concerns exist about the so-called depth of cure. Infrared spectroscopy (FTIR) has traditionally been used to quantify this problem by evaluating the degree of conversion of dental resins. However, Raman scattering provides an alternate method. This article describes the advantages and the limitations of micro-Raman spectroscopy, as compared to FTIR and other techniques, for calculating the local degree of conversion and the depth of cure of light-cured composites.
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Affiliation(s)
- C Pianelli
- Université catholique de Louvain, Laboratoire de Physique et de Chimie des Hauts Polymères, Place Croix du Sud, 1, B-1348 Louvain-la-Neuve, Belgium
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52
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Davidson-Kaban SS, Davidson CL, Feilzer AJ, de Gee AJ, Erdilek N. The effect of curing light variations on bulk curing and wall-to-wall quality of two types and various shades of resin composites. Dent Mater 1997; 13:344-52. [PMID: 9823095 DOI: 10.1016/s0109-5641(97)80105-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
OBJECTIVES This study evaluated the influence of light intensity and irradiation time variations on the curing efficacy of two types and various shades of resin composites and the effect of reduced light intensity on the preservation of wall-to-wall continuity. MATERIALS AND METHODS Three microfilled composites (in three different shades) and one hybrid composite were used in this study. Polymerization shrinkage, and the hardness and adaptation of adhesive restorations in dentin cavities were determined at light intensities of 175 and 700 mW/cm2 and irradiation times of 10 and 60 s. Data were compared using in a general linear model analysis. RESULTS Shrinkage measurements were the indication of conversion and conversion rate. Reduced intensity slowed down the rate of polymerization but did not reduce the conversion as long as an irradiation time of 60 s was employed. High-energy irradiation caused increased separation of the composite from the tooth structure. On the basis of obtaining optimal conversion and adaption, it was demonstrated that the irradiation time to be more effective than irradiation energy. SIGNIFICANCE Light-cured composites require an understanding of their structure, pigmentation and irradiation parameters to obtain optimal performance. High intensity light-curing does not necessarily lead to optimal quality.
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Affiliation(s)
- S S Davidson-Kaban
- Department of Restorative Dentistry and Endodontics, School of Dentistry, University of Ege, Izmir, Turkey.
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53
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Shortall AC, Wilson HJ, Harrington E. Depth of cure of radiation-activated composite restoratives--influence of shade and opacity. J Oral Rehabil 1995; 22:337-42. [PMID: 7616343 DOI: 10.1111/j.1365-2842.1995.tb00782.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Inadequate depth of cure may reduce the longevity of visible light-activated composite restorations. Radiation-activated composites, originally marketed for the restoration of anterior teeth, have been developed and refined for restoring occlusal and proximal cavities in posterior teeth. Clinical factors such as the accessibility of the light source, the direction of the light, intervening tooth tissue and cavity depth may limit depth of cure. Unfortunately, a hard top surface is no indication of adequate polymerization at the base of the cavity. The current investigation used a penetrometer to evaluate the depth of cure of a range of recently introduced 'universal' composite materials and assess the influence of shade and opacity on depth of cure. Depth of cure of the enamel opacity is always greater than that of the same shade of dentine for each manufacturer's product range.
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Affiliation(s)
- A C Shortall
- University of Birmingham, School of Dentistry, U.K
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54
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Taira M, Yamaki M. Studies on optical properties of a visible-light-cured dental composite resin by diffuse reflectance measurements. ACTA ACUST UNITED AC 1995. [DOI: 10.1007/bf00318255] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Pilo R, Brosh T, Lugassy H, Baharav H, Helft M. The effect of irradiation time on the shear strength of composites. Dent Mater 1994; 10:338-42. [PMID: 7498596 DOI: 10.1016/0109-5641(94)90056-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
OBJECTIVES The purpose of this study was to determine the shear strength of composites at a specific depth by a double shear test and to relate it to irradiation time. METHODS Aluminum molds filled with three different composites were irradiated for the manufacturer's recommended time, as well as for three longer and two shorter times. Fifteen cylindrical specimens were prepared for each combination of material and exposure time and subjected to a double shear test based on the principle of rivets connecting various structural members. The shear planes were symmetrically located 1.5 mm from both outer surfaces. RESULTS Shear strength vs. irradiation time was directly but nonlinearly related. All test materials attained a maximum shear strength value which was not exceeded by a further increase of the exposure time. Maximum values obtained were 42.5 MPa for Heliomolar (Vivadent) and Durafill (Kulzer) and 66.9 MPa for P-50 (3M). Only the shear strengths using the shortest light activation time were significantly different for each product. SIGNIFICANCE Shear strength of composites at a specific depth is a function of the combination of light energy and the attenuating power of the specific material. A double shear test might serve as an adjunct to microhardness in determining the extent of cure of composites at a specific depth. The advantage of this testing is the extra information to be gathered regarding the ability of composites to withstand internal stresses at a predetermined distance.
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Affiliation(s)
- R Pilo
- Department of Oral Rehabilitation, Goldschleger School of Dental Medicine, Tel Aviv, Israel
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56
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Kawaguchi M, Fukushima T, Miyazaki K. The relationship between cure depth and transmission coefficient of visible-light-activated resin composites. J Dent Res 1994; 73:516-21. [PMID: 8120215 DOI: 10.1177/00220345940730020601] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The relationships between the transmission coefficient and the cure depth were evaluated on eight commercially available light-activated resin composites. The determination of transmission coefficient was carried out by the use of a radiometer for various shades of the resin composites. The transmission coefficient, ranging from 0.042 to 0.263, was dependent upon the shade of the resin. There was a good correlation between the transmission coefficient and the cure depth for different shades for each resin composite, except for one hybrid resin composite (P-50). The microfilled resin composite showed transmission coefficient and cure depth lower than those of the hybrid and small-particle-filled resin composites.
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Affiliation(s)
- M Kawaguchi
- Department of Dental Materials and Devices, Fukuoka Dental College, Japan
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57
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Abstract
An oscillating rheometer was constructed to study the polymerization of light-cured dental composites. The instrument is based on the forced harmonic oscillator, where the polymerization of the sample leads to a reduction of amplitude of oscillations. The polymerization time as determined for different materials seemed to be influenced by the filler particle size. The results obtained for the viscosity and shear modulus for a class of samples agreed with values published using other instruments and methods.
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Affiliation(s)
- E Rubbi
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Brazil
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58
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Pilo R, Cardash HS. Post-irradiation polymerization of different anterior and posterior visible light-activated resin composites. Dent Mater 1992; 8:299-304. [PMID: 1303371 DOI: 10.1016/0109-5641(92)90104-k] [Citation(s) in RCA: 117] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The Knoop hardness number was measured for bottom and top surfaces of 2 mm thick specimens of different anterior and posterior visible light-cured composites. The variables for this study included various exposure times and a series of time intervals from immediately after curing up to 72 h. Post-irradiation microhardness at the bottom and top surfaces increased rapidly over the first hour, was slower during 24 h and showed no further increase after 24 h. Increasing exposure time resulted in higher microhardness values at both surfaces. Magnitudes of change were larger for the bottom surface. Exposure times longer than those recommended by the manufacturers were needed, especially for the anterior microfilled composites, to achieve adequately photo-activated resin that had an optimum bottom/top surface microhardness of 80-90%. Maximum hardness values were found to be dependent on the volumetric fraction but not on the average inorganic filler size. The post-irradiation increase in hardness value was independent of composite parameters and is probably commensurate with polymerization kinetics.
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Affiliation(s)
- R Pilo
- Department of Oral Rehabilitation, Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Israel
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59
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Uno S, Asmussen E. Selected variables in bonding to dentin. SCANDINAVIAN JOURNAL OF DENTAL RESEARCH 1992; 100:130-2. [PMID: 1574679 DOI: 10.1111/j.1600-0722.1992.tb01725.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The aim of this study was to investigate the effect of three variables on the shear bond strength between a composite resin and dentin treated with a simplified Gluma system. Thickness of material (2 or 3 mm), distance between light guide and the surface of composite resin (0, 1, 3, or 5 mm) and irradiation time (10, 20, 40, or 60 s) were selected as variables. Thickness of material and distance between light guide and composite resin affected bond strength, but there was little influence of irradiation time under the conditions of the study. It is suggested that bond strength depends on the amount of light transmitted through the composite.
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Affiliation(s)
- S Uno
- School of Dentistry, Hokkaido University, Sapporo, Japan
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60
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Lundin SA, Koch G. Cure profiles of visible-light-cured Class II composite restorations in vivo and in vitro. Dent Mater 1992; 8:7-9. [PMID: 1521688 DOI: 10.1016/0109-5641(92)90045-e] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The degrees of conversion of posterior composite material in Class II restorations performed in vivo and in vitro were studied by means of the Raman spectroscopy method. Class II restorations in 13 contralateral pairs of premolars were analyzed. The average difference of the ratio I 1610 cm-1/I 1640 cm-1 between the in vivo- and in vitro-performed restorations was 0.42. This indicates a higher grade of conversion in the in vivo situation.
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Affiliation(s)
- S A Lundin
- The Postgraduate Dental Education Center, Orebro, Sweden
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61
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Abstract
The aim of this study was to investigate the effect of the thickness of dentin (1, 2, or 3 mm) placed between the light guide and the composite resin on the shear bond strength to dentin treated with a simplified Gluma system. The effects of the thickness of composite resin (2 or 3 mm), irradiation time (20, 40, or 60 sec), and shade (universal or brown) were also examined. The results showed that the thickness of dentin influenced bonding and interacted with the other three variables. It is suggested that dentin located between the light guide and composite resin may attenuate the light aimed at the bonding interface in the same manner as a layer of composite resin.
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Affiliation(s)
- S Uno
- School of Dentistry, Hokkaido University, Sapporo, Japan
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62
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Atmadja G, Bryant RW. Some factors influencing the depth of cure of visible light-activated composite resins. Aust Dent J 1990; 35:213-8. [PMID: 2393355 DOI: 10.1111/j.1834-7819.1990.tb05394.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Some of the factors influencing the depth of cure of four composite resins of different composition were examined. Knoop hardness measurements were carried out at the surface and 1, 2, 3, 4 and 6 mm below the surface to which the light was applied. The hardness of the composites decreased with increasing depth and shorter exposure times. The composites continued to polymerize after removal of the light source. Composition of the composite resin has a major effect on the surface hardness and depth of polymerization.
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Affiliation(s)
- G Atmadja
- Department of Conservative Dentistry, University of Indonesia, Jakarta
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63
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Blackman R, Barghi N, Duke E. Influence of ceramic thickness on the polymerization of light-cured resin cement. J Prosthet Dent 1990; 63:295-300. [PMID: 2308089 DOI: 10.1016/0022-3913(90)90199-m] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The curing of two light-activated resin cements under two ceramic materials was examined to assess the influence of ceramic thickness on polymerization. The degree of resin cure was determined by microhardness measurements (Knoop) on resin cement samples cured under five ceramic thicknesses with light exposures of 30 to 120 seconds. These cements cured under thin ceramic specimens with recommended exposures. With thick ceramics, both cements cured better under the glass-ceramic, but neither reached a level of maximum cure under the porcelain.
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Affiliation(s)
- R Blackman
- Department of Restorative Dentistry, University of Texas Health Science Center, Dental School, San Antonio
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64
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Pagniano RP, Longenecker S, Chandler H. Effect of unit and operatory lights on the consistency of light-activated composites. J Prosthet Dent 1989; 61:150-2. [PMID: 2715946 DOI: 10.1016/0022-3913(89)90363-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The extent to which the flow of composite resin is reduced when exposed to dental lights was studied. Samples were exposed to operating lights of various intensities for varying periods of time. After exposure each sample was placed under a fixed load and the resulting average diameter was calculated. Data from the testing of samples exposed to dental lights were analyzed by a two-way analysis of variance with subsequent Tukey multiple comparison test. Diameter comparisons were significant (p less than 0.05) between the controls and samples exposed to the 960 fc light at 6 minutes, the 1920 fc light at 4 minutes, the 2880 fc light at 2 minutes, and the 5120 and 7680 fc lights at 1 minute. The smaller diameters observed with respect to increased intensity and time of exposure show that either variable or the combination of both variables will alter the consistency of composite resin.
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Affiliation(s)
- R P Pagniano
- Section of Restorative and Prosthetic Dentistry, Ohio State University, College of Dentistry, Columbus
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65
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66
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Walls AW, McCabe JF, Murray JJ. The polymerization contraction of visible-light activated composite resins. J Dent 1988; 16:177-81. [PMID: 3183151 DOI: 10.1016/0300-5712(88)90032-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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67
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Jendresen MD, Klooster J, Phillips RW, Schallhorn RG, Sullivan MM. Report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry. J Prosthet Dent 1987; 57:734-64. [PMID: 3295206 DOI: 10.1016/0022-3913(87)90374-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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68
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DeWald JP, Ferracane JL. A comparison of four modes of evaluating depth of cure of light-activated composites. J Dent Res 1987; 66:727-30. [PMID: 3475304 DOI: 10.1177/00220345870660030401] [Citation(s) in RCA: 150] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Four commonly used methods for evaluating depth of cure in light-activated composites were compared. Optical and scraping methods correlate well, but severely overestimate depth of cure as compared with hardness testing or degree of conversion analysis. Degree of conversion appears to be the most sensitive test of depth of cure.
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