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Visible lights and visible light-activated composite resins
Visible lights and visible light-activated composite resins Sheldon M. Newman, D.D.S., M.S.,* G. Allen Murray, D.D.S.,** and Jere L. Yates, D.D.S., M.S.*** University
of Tennessee,
College of Dentistry,
Memphis,
Tenn.
U
ltraviolet light (W)-activated composite resins serve a useful purpose.‘,* The depth of cure provided by the various UV systems has contributed to their acceptance.3 Recently, the visible light-activated composite resins have gained in popularity. At the start of this investigation, there were 11 visible light-activated composite resins and eight visible lights for their polymerization on the market. Some manufacturers claim 4 mm depth of polymerization in a 20-second exposure to a visible light. This depth is greater and the exposure time shorter than that reported for UVactivated composite resins.3 There have been several reports on visible lightactivated systems.4-9Swartz et al.’ found that these resins could be polymerized through 1 mm of enamel. Like Swartz et al.,4 Leung et aL5 found that a greater exposure time increased the hardness of the specimen at a particular depth. All studies were made in metal or plastic molds except for one cliaical report.‘j The purpose of this study was to compare the depth of polymerization in teeth of combinations of 11 visible light-activated composite resins and the eight visible lights. These results were compared with those obtained from the previous study on W-activated systems.3
MATERIAL
AND METHODS
Class V preparations were prepared in 440 freshly extracted human teeth to a depth of 4.5 to 5 mm. Table I presents the visible light-activated materials, the shade used, and the manufacturer. The shade was the one that appeared the most universally applicable, not necessarily the lightest. Each material was inserted into 55 preparations. Five samples of each type of material were polymerized for 20 seconds by each of the following lights: (1) Prismalight (L. D. Caulk Co.,
*Assistant Professor, Department of Biomaterials. **Associate Professor, Department of Biomaterials. ***Associate Professor, Department of Pedodontics.
THE JOURNAL
OF PROSTHETIC
DENTISTRY
Milford, Del.), (2) Translux (Degussa, Inc., Placentia, Calif.), (3) Elipar (Espe-Premier, Nor&town, Pa.), (4) Heliomat (Vivadent, Inc., Tonawanda, N.Y.), (5) Dentalite (Systemetrics, Roseville, Calif.), (6) Visar Light 1 (Den-Mat, Santa Maria, Calif.), (7) Spectralite (Pentron Corp., Wallingford, Conn.), and (8) Command (Sybron/Kerr, Romulus, Mich.). All but one of the visible light sources use an optical cord between the light source/power supply and the exit of the beam to expose the tooth. The one exception is the Elipar light, which has an electrical cord between a power source and a gun containing the light source and an optical rod that is carried to the mouth. The lights are shown in Fig. 1. After polymerization the restored teeth were kept in a 37” C incubator in tap water for 24 hours. The teeth were then sectioned longitudinally through the restoration on a wet aluminum oxide grinding wheel. A Unitron stereoscopic microscope (Unitron, Newton Highland, Mass.) with a micrometer attachment was used to measure the depth of each preparation and the depth of polymerization of each restoration. The depth was determined by a noticeable change in translucence. The demarcation was verified by testing the ground surface of the restorative material. An example is shown in Fig. 2. The depths of polymerization were subjected to both a two-way and a series of one-way analyses of variance (ANOVA). The analyses were followed by the Newman-Keuls a posteriori test to rank order the differences found. All statistical analyses were run to meet an (Y = 0.01 level of significance.
RESULTS The mean depth of polymerization in millimeters and the standard deviation of each combination of light and material appear in Table II. This table also includes the mean depth for each material across all lights and the mean depth for each light across all materials. A two-way ANOVA, which indicated a high degree of interaction, was run. Therefore, one-way
31
NEWMAN,
Table I. Visible light-activated No.
composite
1
Shade
Prismafill Durafill Visio-fil Visio-dispers Heliosit Silux Visar-fil Spectra-M Command Superfil Lite
AND
YATES
resin, shade used, and manufacturer
Material
2 3 4 5 6 7 8 9 10 11
MURRAY,
Manufacturer
Light Universal Standard Standard No. 22 Universal No. 62 Universal Universal Universal Yellow
L. D. Caulk Co., Milford, Del. Degussa, Inc., Placentia, Calif. Espe-Premier, Norristown, Pa. Espe-Premier, Norristown, Pa. Vivadent, Inc., Tonawanda, N.Y. 3 M Co., St. Paul, Minn. Den-Mat, Santa Maria, Calif. Pentron Corp., Wallingford, Conn. Sybron/Kerr, Romulus, Mich. H. J. Bosworth, Skokie, Ill. Phasealloy, Inc., El Cajon, Calif.
l
Table II. Mean depth of polymerization (in millimeters) of each combination of light and material
and standard deviations
(in parentheses)
Lights Resins Prismafill Durafill Visio-fil Visio-dispers Heliosit Silux Visar-fil Spectra-RI Command Superfil Lite Pooled lights
Prismalight
Translux
Elipar
Heliomat
Dentalite
Visar Light 1
Spectralite
4.866 (0.22) 3.994 (0.57) 4.167 (0.33) 3.451 (0.41) 3.914 (0.30) 4.223 (0.36) 2.406 (0.28) 3.259 (0.53) 2.819 (0.43) 3.668 (0.26) 3.850 (0.71) 3.692 (0.85)
3.701 (0.35) 3.239 (0.42) 3.803 (0.62) 2.824 (0.36) 3.048 (0.41) 3.536 (0.33) 2.160 (0.42) 2.881 (0.31) 2.963 (0.06) 3.041 (0.24) 3.003 (0.33) 3.099 (0.63)
4.848 (0.36) 3.820 (0.52) 4.644 (0.47) 3.927 (0.40) 3.375 (0.41) 3.902 (0.38) 2.933 (0.33) 2.843 (0.41) 3.834 (0.35) 2.816 (0.23) 3.381 (0.36) 3.666 (0.82)
4.284 (0.61) 3.926 (0.43) 4.192 (0.30) 3.978 (0.31) 3.561 (0.27) 3.710 (0.35) 2.269 (0.28) 3.227 (0.39) 2.783 (0.39) 4.131 (0.42) 3.774 (0.10) 3.631 (0.76)
3.085 (0.47) 2.251 (0.27) 2.239 (0.20) 2.767 (0.43) 1.908 (1.05) 2.210 (0.20) 1.421 (0.38) 1.771 (0.40) 1.152 (0.76) 3.144 (0.29) 2.695 (0.05) 2.240 (0.85)
3.918 (0.47) 2.839 (0.55) 3.348 (0.24) 3.005 (0.39) 2.810 (0.42) 4.096 (0.33) 2.019 (0.06) 2.823 (0.37) 2.709 (0.26) 3.568 (0.24) 2.763 (0.24) 3.077 (0.73)
2.613 (0.41) 1.952 (0.59) 2.390 (0.31) 1.894 (0.33) 2.621 (0.68) 2.223 (0.14) 1.397 (0.21) 1.883 (0.18) 1.561 (0.18) 2.266 (0.38) 2.418 (0.74) 2.111 (0.57)
ANOVAs were run on each light, each material, and on the two sets of pooled data. All ANOVAs revealed statistically significant differences at the CY= 0.01 level. A Newman-Keuls a posteriori test was run on each set of data to indicate the materials or lights that produced greater depths of polymerization at the CY= 0.01 level. These statistics appear in Table III for lights, Table IV for materials, and Table V for pooled data.
32
Command 3.633 (0.33) 3.063 (0.30) 3.428 (0.48) 3.314 (0.45) 2.980
Pooled materials 3.881 (0.91) 3.135 (0.93) 3.520 (0.98) 3.145 (0.81) 3.017 (0.86) 3.411 (0.88) 2.065 (0.60) 2.672 (0.69) 2.539 '(0.96) 3.198 (0.67) 3.142 (0.66)
ww
3.388 (0.38) 1.915 (0.13) 2.689 (0.39) 2.518 (0.43) 2.955 (0.18) 3.251 (0.51) 3.012 (0.65)
DISCUSSION The data indicate significant differences in the ability of various visible lights to polymerize visible light-activated composite resins. There were also significant differences in the depth to which the various composite resins polymerized. Prismafill was polymerized the deepest by both the Prismalight and the Elipar light (Table II). Because all the one-way ANOVAs indicated that variations existed, one can start with the results of Prismafill with
JULY 1983
VOLUME
50
NUMBER
1
VISIBLE
LIGHT-ACTIVATED
COMPOSITE
RESINS
1. Visible light sources examined in this study. I, Prismalight; 2, Translux; 4, Heliomat; 5, Dentalite; 6, Visar Light 1; 7, Spectralite; and 8, Command.
Fig.
3, Elipar;
Table III. Under each light is a list of materials by number* in order from greatest depth of polymerization on top (the lines designate materials that cannot be differentiated at the (Y = 0.01 level on a Newman-Keuls a posteriori test) Prismalight 1 6
Fig. 2. A cross-sectional cut through restorative material in tooth. Note difference in translucence between polymerized material toward exposed surface and nonpolymerized material toward depths of preparation. Arrow points to holes produced by an explorer identifying this junction.
each of the two lights just mentioned and follow through the Newman-Keuls a posteriori tests to see where differences exist. The Newman-Keuls tests (Table IV) revealed no statistically significant difference between Prismalight, Elipar, or Heliomat. This nondifferentiation held fairly consistently for every material. When all those data were pooled and the
THE JOURNAL
OF PROSTHETIC
DENTISTRY
3 2 5 11 10 4 8 9 7
Dentalite 10 1 4 11 2 3 6 5 8 7 9
Elipar 3 1 6 2 10 11 5 9 8 4 7
Visar Light 1 6 1 10 3 4 2 8 5 11 9 7
1
3 4 6 9 2 11 5 7 8 10
I
Spectralite 5 1 11 3 10 6 2 4 8 9 7
Hblioma 1 3 10 4 2 11 6 5 8 9 7 I
It
Command 1 3 6 4 11 2 5 10 8 9 7 I
*Numbers identified in Table I.
33
NEWMAN,
MURRAY,
AND
YATES
Table IV. Under each material is a list of lights by number* in order from greatest depth of polymerization on top (the lines designate materials that cannot be differentiated at the (Y = 0.01 level on a Newman-Keuls a posteriori test) Durafill
Prismafill
Visio-fil
1 3 4 6 2 8 5 7 /
Silux 1 6 3 4 2 8 7 5
Visio-dispers 4 3 1 8 6 2 5 7
:(I 1 I 2 86 /I 75 I
Spectra4 1
Visar-fil 3 1 4 2 6 8 5 7
4 2 3 6 8 7 5
Heliosit
I
Command
Superfil
3 2 1 4 6 8 7 5
4 1 6 5 2 8 3 7
Lite 1 4 3 8 2 6 5 7
*Numbers indicated in Fig. 1.
Table V. Pooled data analyzed at the cx = 0.01 level on the Newman-Keuls Order of materials* across all lights 1 3 6 10 4 11 2 5 8 9 7
a posteriori
test
Order of lights+ across all materials
7
*Numbers of materials indicated in Table I. tNumbers of lights indicated in Fig. I.
lights compared in Table V, these three lights could not be differentiated in giving the greatest depth of polymerization, The shallowest depths consistently resulted from exposure to the Dentalite and the Spectralite. The materials Prismafill, Visio-fil, and Silux could not be differentiated on the Newman-Keuls tests shown in Table III. Again, the pooled data in Table V showed that these three materials could not be differentiated in being polymerized to the greatest depth. The materials that consistently gave the least depth of polymerization were Visar-fil and Command.
34
Darker shades offer less depth of polymerization.’ In this study an attempt was made to achieve consistency by choosing the most universal or most widely applicable shade. This meant that the lightest shade was not used in the study. Thus, the comparisons were made on materials that would have the widest clinical use. The data produced reflect only the depth of polymerization, which does not necessarily have any correlation with the degree of polymerization. There could be wide variations in how much each material was polymerized at a particular depth. This degree of polymerization could greatly affect the strength of the resin.‘O Abrasion resistance could also be affected. A t-test was run to compare the system that gave the greatest depth of polymerization (4.87 mm) among visible light combinations with that system among the UV light combinations. The earlier work by Murray et al.’ found that Estilux with the Duralux light gave the greatest depth of polymerization at 20 seconds (3.1 mm). The visible light system had a greater depth of polymerization at the a! = 0.01 level of confidence.
CONCLUSIONS There were large variations among the abilities of different visible light sources to polymerize the various visible light-activated composite resins. The lights that produced the greatest depths of polymerization were Prismalight, Elipar, and Heliomat. The materials that were polymerized to the greatest depths were Prisma-
JULY 1983
VOLUME
50
NUMBER
1
VISIBLE
LIGHT-ACTIVATED
COMPOSITE
RESINS
fill, Visio-fil, and Silux. The visible light curing system produced a greater depth of polymerization than the UV light-activated compositeresins.
REFERENCES 1. Buonocore, M. G., and Davial, J.: Restoration of fractured anterior teeth with ultraviolet light-polymerized bonding materials: A new technique. J Am Dent Assoc 861349, 1973. 2. Lee, H. L., Orlowski, J. A., and Rogers, B. J.: A comparison of ultraviolet luting and self-curing polymers in preventive, restorative, and orthodontic dentistry. Int Dent J 26:134, 1976. 3. Murray, G. A., Yates, J. L., and Newman, S. M.: Ultraviolet light and ultraviolet light-activated composite resins. J PROSTHET DENT 46~167, 1981. 4. Swarm, M. L., Phillips, R. W., and Rhodes, B. F.: Visible light-activated resins-Depth of cure. J Dent Res 61:270, 1982.
THE JOURNAL
OF PROSTHETIC
DENTISTRY
Leung, R., Fan, P. L., and Johnston, W. M.: Exposure time and thickness on polymerization of visible light composite. J Dent Res 61:248, 1982. 6. Sluder, T. B., Sockwell, C. L., and Leinfelder, K. S.: Two-year clinical evaluation of two light-cured composite resins. J Dent Res 61:214, 1982. 7. Viohl, J., and Kops, C.: Bond strength of auto- and photopolymerizing restorative resins. J Dent Res 61:270, 1982. 8. Denyer, R., and Shav, D. J.: Cure evaluation of visible light composites by Knoop hardness measurement. J Dent Res 61:271, 1981. 9. Pollack, B. F., and Lewis, A. L.: Visible light resin-curing generators: A comparison. Gen Dent 29~488, 1981. 10. Ferracane, J. L., Newman, S. M., and Greener, E. H.: Correlation of strength and degree of polymerization of unfilled Bis-GMA. J Dent Res 61:271, 1982. 5.
Reprint requests to: DR. SHELDONM. NEWMAN UNIVERSITYOF TENNESSEE COLLEGEOF DENTISTRY MEMPHIS, TN 38163
35
of Tennessee,
College of Dentistry,
Memphis,
Tenn.
U
ltraviolet light (W)-activated composite resins serve a useful purpose.‘,* The depth of cure provided by the various UV systems has contributed to their acceptance.3 Recently, the visible light-activated composite resins have gained in popularity. At the start of this investigation, there were 11 visible light-activated composite resins and eight visible lights for their polymerization on the market. Some manufacturers claim 4 mm depth of polymerization in a 20-second exposure to a visible light. This depth is greater and the exposure time shorter than that reported for UVactivated composite resins.3 There have been several reports on visible lightactivated systems.4-9Swartz et al.’ found that these resins could be polymerized through 1 mm of enamel. Like Swartz et al.,4 Leung et aL5 found that a greater exposure time increased the hardness of the specimen at a particular depth. All studies were made in metal or plastic molds except for one cliaical report.‘j The purpose of this study was to compare the depth of polymerization in teeth of combinations of 11 visible light-activated composite resins and the eight visible lights. These results were compared with those obtained from the previous study on W-activated systems.3
MATERIAL
AND METHODS
Class V preparations were prepared in 440 freshly extracted human teeth to a depth of 4.5 to 5 mm. Table I presents the visible light-activated materials, the shade used, and the manufacturer. The shade was the one that appeared the most universally applicable, not necessarily the lightest. Each material was inserted into 55 preparations. Five samples of each type of material were polymerized for 20 seconds by each of the following lights: (1) Prismalight (L. D. Caulk Co.,
*Assistant Professor, Department of Biomaterials. **Associate Professor, Department of Biomaterials. ***Associate Professor, Department of Pedodontics.
THE JOURNAL
OF PROSTHETIC
DENTISTRY
Milford, Del.), (2) Translux (Degussa, Inc., Placentia, Calif.), (3) Elipar (Espe-Premier, Nor&town, Pa.), (4) Heliomat (Vivadent, Inc., Tonawanda, N.Y.), (5) Dentalite (Systemetrics, Roseville, Calif.), (6) Visar Light 1 (Den-Mat, Santa Maria, Calif.), (7) Spectralite (Pentron Corp., Wallingford, Conn.), and (8) Command (Sybron/Kerr, Romulus, Mich.). All but one of the visible light sources use an optical cord between the light source/power supply and the exit of the beam to expose the tooth. The one exception is the Elipar light, which has an electrical cord between a power source and a gun containing the light source and an optical rod that is carried to the mouth. The lights are shown in Fig. 1. After polymerization the restored teeth were kept in a 37” C incubator in tap water for 24 hours. The teeth were then sectioned longitudinally through the restoration on a wet aluminum oxide grinding wheel. A Unitron stereoscopic microscope (Unitron, Newton Highland, Mass.) with a micrometer attachment was used to measure the depth of each preparation and the depth of polymerization of each restoration. The depth was determined by a noticeable change in translucence. The demarcation was verified by testing the ground surface of the restorative material. An example is shown in Fig. 2. The depths of polymerization were subjected to both a two-way and a series of one-way analyses of variance (ANOVA). The analyses were followed by the Newman-Keuls a posteriori test to rank order the differences found. All statistical analyses were run to meet an (Y = 0.01 level of significance.
RESULTS The mean depth of polymerization in millimeters and the standard deviation of each combination of light and material appear in Table II. This table also includes the mean depth for each material across all lights and the mean depth for each light across all materials. A two-way ANOVA, which indicated a high degree of interaction, was run. Therefore, one-way
31
NEWMAN,
Table I. Visible light-activated No.
composite
1
Shade
Prismafill Durafill Visio-fil Visio-dispers Heliosit Silux Visar-fil Spectra-M Command Superfil Lite
AND
YATES
resin, shade used, and manufacturer
Material
2 3 4 5 6 7 8 9 10 11
MURRAY,
Manufacturer
Light Universal Standard Standard No. 22 Universal No. 62 Universal Universal Universal Yellow
L. D. Caulk Co., Milford, Del. Degussa, Inc., Placentia, Calif. Espe-Premier, Norristown, Pa. Espe-Premier, Norristown, Pa. Vivadent, Inc., Tonawanda, N.Y. 3 M Co., St. Paul, Minn. Den-Mat, Santa Maria, Calif. Pentron Corp., Wallingford, Conn. Sybron/Kerr, Romulus, Mich. H. J. Bosworth, Skokie, Ill. Phasealloy, Inc., El Cajon, Calif.
l
Table II. Mean depth of polymerization (in millimeters) of each combination of light and material
and standard deviations
(in parentheses)
Lights Resins Prismafill Durafill Visio-fil Visio-dispers Heliosit Silux Visar-fil Spectra-RI Command Superfil Lite Pooled lights
Prismalight
Translux
Elipar
Heliomat
Dentalite
Visar Light 1
Spectralite
4.866 (0.22) 3.994 (0.57) 4.167 (0.33) 3.451 (0.41) 3.914 (0.30) 4.223 (0.36) 2.406 (0.28) 3.259 (0.53) 2.819 (0.43) 3.668 (0.26) 3.850 (0.71) 3.692 (0.85)
3.701 (0.35) 3.239 (0.42) 3.803 (0.62) 2.824 (0.36) 3.048 (0.41) 3.536 (0.33) 2.160 (0.42) 2.881 (0.31) 2.963 (0.06) 3.041 (0.24) 3.003 (0.33) 3.099 (0.63)
4.848 (0.36) 3.820 (0.52) 4.644 (0.47) 3.927 (0.40) 3.375 (0.41) 3.902 (0.38) 2.933 (0.33) 2.843 (0.41) 3.834 (0.35) 2.816 (0.23) 3.381 (0.36) 3.666 (0.82)
4.284 (0.61) 3.926 (0.43) 4.192 (0.30) 3.978 (0.31) 3.561 (0.27) 3.710 (0.35) 2.269 (0.28) 3.227 (0.39) 2.783 (0.39) 4.131 (0.42) 3.774 (0.10) 3.631 (0.76)
3.085 (0.47) 2.251 (0.27) 2.239 (0.20) 2.767 (0.43) 1.908 (1.05) 2.210 (0.20) 1.421 (0.38) 1.771 (0.40) 1.152 (0.76) 3.144 (0.29) 2.695 (0.05) 2.240 (0.85)
3.918 (0.47) 2.839 (0.55) 3.348 (0.24) 3.005 (0.39) 2.810 (0.42) 4.096 (0.33) 2.019 (0.06) 2.823 (0.37) 2.709 (0.26) 3.568 (0.24) 2.763 (0.24) 3.077 (0.73)
2.613 (0.41) 1.952 (0.59) 2.390 (0.31) 1.894 (0.33) 2.621 (0.68) 2.223 (0.14) 1.397 (0.21) 1.883 (0.18) 1.561 (0.18) 2.266 (0.38) 2.418 (0.74) 2.111 (0.57)
ANOVAs were run on each light, each material, and on the two sets of pooled data. All ANOVAs revealed statistically significant differences at the CY= 0.01 level. A Newman-Keuls a posteriori test was run on each set of data to indicate the materials or lights that produced greater depths of polymerization at the CY= 0.01 level. These statistics appear in Table III for lights, Table IV for materials, and Table V for pooled data.
32
Command 3.633 (0.33) 3.063 (0.30) 3.428 (0.48) 3.314 (0.45) 2.980
Pooled materials 3.881 (0.91) 3.135 (0.93) 3.520 (0.98) 3.145 (0.81) 3.017 (0.86) 3.411 (0.88) 2.065 (0.60) 2.672 (0.69) 2.539 '(0.96) 3.198 (0.67) 3.142 (0.66)
ww
3.388 (0.38) 1.915 (0.13) 2.689 (0.39) 2.518 (0.43) 2.955 (0.18) 3.251 (0.51) 3.012 (0.65)
DISCUSSION The data indicate significant differences in the ability of various visible lights to polymerize visible light-activated composite resins. There were also significant differences in the depth to which the various composite resins polymerized. Prismafill was polymerized the deepest by both the Prismalight and the Elipar light (Table II). Because all the one-way ANOVAs indicated that variations existed, one can start with the results of Prismafill with
JULY 1983
VOLUME
50
NUMBER
1
VISIBLE
LIGHT-ACTIVATED
COMPOSITE
RESINS
1. Visible light sources examined in this study. I, Prismalight; 2, Translux; 4, Heliomat; 5, Dentalite; 6, Visar Light 1; 7, Spectralite; and 8, Command.
Fig.
3, Elipar;
Table III. Under each light is a list of materials by number* in order from greatest depth of polymerization on top (the lines designate materials that cannot be differentiated at the (Y = 0.01 level on a Newman-Keuls a posteriori test) Prismalight 1 6
Fig. 2. A cross-sectional cut through restorative material in tooth. Note difference in translucence between polymerized material toward exposed surface and nonpolymerized material toward depths of preparation. Arrow points to holes produced by an explorer identifying this junction.
each of the two lights just mentioned and follow through the Newman-Keuls a posteriori tests to see where differences exist. The Newman-Keuls tests (Table IV) revealed no statistically significant difference between Prismalight, Elipar, or Heliomat. This nondifferentiation held fairly consistently for every material. When all those data were pooled and the
THE JOURNAL
OF PROSTHETIC
DENTISTRY
3 2 5 11 10 4 8 9 7
Dentalite 10 1 4 11 2 3 6 5 8 7 9
Elipar 3 1 6 2 10 11 5 9 8 4 7
Visar Light 1 6 1 10 3 4 2 8 5 11 9 7
1
3 4 6 9 2 11 5 7 8 10
I
Spectralite 5 1 11 3 10 6 2 4 8 9 7
Hblioma 1 3 10 4 2 11 6 5 8 9 7 I
It
Command 1 3 6 4 11 2 5 10 8 9 7 I
*Numbers identified in Table I.
33
NEWMAN,
MURRAY,
AND
YATES
Table IV. Under each material is a list of lights by number* in order from greatest depth of polymerization on top (the lines designate materials that cannot be differentiated at the (Y = 0.01 level on a Newman-Keuls a posteriori test) Durafill
Prismafill
Visio-fil
1 3 4 6 2 8 5 7 /
Silux 1 6 3 4 2 8 7 5
Visio-dispers 4 3 1 8 6 2 5 7
:(I 1 I 2 86 /I 75 I
Spectra4 1
Visar-fil 3 1 4 2 6 8 5 7
4 2 3 6 8 7 5
Heliosit
I
Command
Superfil
3 2 1 4 6 8 7 5
4 1 6 5 2 8 3 7
Lite 1 4 3 8 2 6 5 7
*Numbers indicated in Fig. 1.
Table V. Pooled data analyzed at the cx = 0.01 level on the Newman-Keuls Order of materials* across all lights 1 3 6 10 4 11 2 5 8 9 7
a posteriori
test
Order of lights+ across all materials
7
*Numbers of materials indicated in Table I. tNumbers of lights indicated in Fig. I.
lights compared in Table V, these three lights could not be differentiated in giving the greatest depth of polymerization, The shallowest depths consistently resulted from exposure to the Dentalite and the Spectralite. The materials Prismafill, Visio-fil, and Silux could not be differentiated on the Newman-Keuls tests shown in Table III. Again, the pooled data in Table V showed that these three materials could not be differentiated in being polymerized to the greatest depth. The materials that consistently gave the least depth of polymerization were Visar-fil and Command.
34
Darker shades offer less depth of polymerization.’ In this study an attempt was made to achieve consistency by choosing the most universal or most widely applicable shade. This meant that the lightest shade was not used in the study. Thus, the comparisons were made on materials that would have the widest clinical use. The data produced reflect only the depth of polymerization, which does not necessarily have any correlation with the degree of polymerization. There could be wide variations in how much each material was polymerized at a particular depth. This degree of polymerization could greatly affect the strength of the resin.‘O Abrasion resistance could also be affected. A t-test was run to compare the system that gave the greatest depth of polymerization (4.87 mm) among visible light combinations with that system among the UV light combinations. The earlier work by Murray et al.’ found that Estilux with the Duralux light gave the greatest depth of polymerization at 20 seconds (3.1 mm). The visible light system had a greater depth of polymerization at the a! = 0.01 level of confidence.
CONCLUSIONS There were large variations among the abilities of different visible light sources to polymerize the various visible light-activated composite resins. The lights that produced the greatest depths of polymerization were Prismalight, Elipar, and Heliomat. The materials that were polymerized to the greatest depths were Prisma-
JULY 1983
VOLUME
50
NUMBER
1
VISIBLE
LIGHT-ACTIVATED
COMPOSITE
RESINS
fill, Visio-fil, and Silux. The visible light curing system produced a greater depth of polymerization than the UV light-activated compositeresins.
REFERENCES 1. Buonocore, M. G., and Davial, J.: Restoration of fractured anterior teeth with ultraviolet light-polymerized bonding materials: A new technique. J Am Dent Assoc 861349, 1973. 2. Lee, H. L., Orlowski, J. A., and Rogers, B. J.: A comparison of ultraviolet luting and self-curing polymers in preventive, restorative, and orthodontic dentistry. Int Dent J 26:134, 1976. 3. Murray, G. A., Yates, J. L., and Newman, S. M.: Ultraviolet light and ultraviolet light-activated composite resins. J PROSTHET DENT 46~167, 1981. 4. Swarm, M. L., Phillips, R. W., and Rhodes, B. F.: Visible light-activated resins-Depth of cure. J Dent Res 61:270, 1982.
THE JOURNAL
OF PROSTHETIC
DENTISTRY
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