The effect of irradiation modes on polymerization and microleakage of composite resin

Jong-Jin Park; Jeong-Won Park; Sung-Ho Park; Ju-Myong Park; Tae-Kyung Kwon; Sung-Kyo Kim

doi:10.5395/JKACD.2002.27.2.158

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Original Article The effect of irradiation modes on polymerization and microleakage of composite resin: Jong-Jin Park, Jeong-Won Park, Sung-Ho Park^*, Ju-Myong Park, Tae-Kyung Kwon, Sung-Kyo Kim; Journal of Korean Academy of Conservative Dentistry 2002;27(2):158-174.
DOI: https://doi.org/10.5395/JKACD.2002.27.2.158
Published online: March 31, 2002

Department of Conservative Dentistry, School of Dentistry, Kyungpook National University, Daegu, Korea.

^*Department of Conservative Dentistry, College of Dentistry, Yonsei University, Seoul, Korea.

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Abstract
REFERENCES

Abstract

The aim of this study was to investigate the effect of light irradiation modes on polymerization shrinkage, degree of cure and microleakage of a composite resin.

VIP™ (Bisco Dental Products, Schaumburg, IL, USA) and Optilux 501™ (Demetron/Kerr, Danbury, CT, USA) were used for curing Filtek™ Z-250 (3M Dental Products, St. Paul., MN, USA) composite resin using following irradiation modes: VIP™ (Bisco) 200mW/cm² (V2), 400mW/cm² (V4), 600mW/cm² (V6), Pulse-delay (200 mW/cm² 3 seconds, 5 minutes wait, 600mW/cm² 30seconds, VPD) and Optilux 501™ (Demetron/Kerr) C-mode (OC), R-mode (OR).

Linear polymerization shrinkage of the composite specimens were measured using Linometer (R&B, Daejeon, Korea) for 90 seconds for V2, V4, V6, OC, OR groups and for up to 363 seconds for VPD group (n=10, each).

Degree of conversion was measured using FTIR spectrometer (IFS 120 HR, Bruker Karlsruhe, Germany) at the bottom surface of 2 mm thick composite specimens. V2, V4, V6, OC groups were measured separately at five irradiation times (5, 10, 20, 40, 60 seconds) and OR, VPD groups were measured in the above mentioned irradiation modes (n=5, each).

Microhardness was measured using Digital microhardness tester (FM7, Future-Tech Co., Tokyo, Japan) at the top and bottom surfaces of 2mm thick composite specimens after exposure to the same irradiation modes as the test of degree of conversion(n=3, each).

For the microleakage test, class V cavities were prepared on the distal surface of the ninety extracted human third molars. The cavities were restored with one of the following irradiation modes: V2/60 seconds, V4/40 seconds, V6/30 seconds, VPD, OC and OR. Microleakage was assessed by dye penetration along enamel and dentin margins of cavities.

Mean polymerization shrinkage, mean degree of conversion and mean microhardness values for all groups at each time were analyzed using one-way ANOVA and Duncan's multiple range test, and using chi-square test for microleakage values.

The results were as follows:

·Polymerization shrinkage was increased with higher light intensity in groups using VIP™ (Bisco): the highest with 600mW/cm², followed by Pulse-delay, 400mW/cm² and 200mW/cm² groups. The degree of polymerization shrinkage was higher with Continuous mode than with Ramp mode in groups using Optilux 501™ (Demetron/Kerr).

·Degree of conversion and microhardness values were higher with higher light intensity. The final degree of conversion was in the range of 44.7 to 54.98% and the final microhardness value in the range of 34.10 to 56.30.

·Microleakage was greater in dentin margin than in enamel margin. Higher light intensity showed more microleakage in dentin margin in groups using VIP™ (Bisco). The micoleakage was the lowest with Continuous mode in enamel margin and with Ramp mode in dentin margin when Optilux 501™(Demetron/Kerr) was used.

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Fig. 1

Schematic drawing of the Linometer with a composite sample placed between the glass plate and aluminium disk.

Fig. 2

Schematical representation of microleakage scoring system. Score 0: no penetration of dye; 1: penetration of dye into half of the cavity depth; 2: penetration of dye beyond half of the cavity depth; 3: penetration of dye into the cavity floor.

Fig. 3

Volumetric polymerization shrinkage (%).

↑indicates the finishing time (20 sec) of irradiation for OR group.

▴indicates the finishing time (60 sec) of irradiation for V2, V4, V6 and OC groups.

Each data represents mean value from 10 specimens.

Fig. 4

Volumetric polymerization shrinkage including VPD group (%).

↑indicates the finishing time (20 sec) of irradiation for OR group.

▴indicates the finishing time (60 sec) of irradiation for V2, V4, V6 and OC groups.

▵indicates the starting time (303 sec) of second irradiation for VPD group.

Each data represents mean value from 10 specimens.

Fig. 5

Initial volumetric polymerization shrinkage(%).

Each data represents mean value from 10specimens.

Fig. 6

Degree of conversion at the bottom surface of 2mm thickness specimens (%).

Each data represents mean value from 5specimens.

Fig. 7

Knoop Hardness Number at the top surface of 2 mm thickness specimens.

Each data represents mean value from 3 specimens.

Fig. 8

Knoop Hardness Number at the bottom surface of 2 mm thickness specimens.

Each data represents mean value from 3 specimens.

Fig. 9

Microleakage score proportions at enamel margin (%).

The data presented are representatives of 30 specimens from V2, 22 specimens from V4, 24 specimens from V6, 24 specimens from OC, 30 specimens from OR and 26 specimens from VPD group.

Fig. 10

Microleakage score proportions at dentin margin (%).

The data presented are representatives of 30 specimens from V2, 22 specimens from V4, 24 specimens from V6, 24 specimens from OC, 30 specimens from OR and 26 specimens from VPD group.

Table 1

Various light curing modes used in this study

Table 2

Linear polymerization shrinkage (10^-3mm)

Values are mean(standard deviation)^*.

^*The same superscript letters denote mean values with no statistically significant difference (p>0.01). Duncan grouping was done only within the same time interval.

Thickness of resin specimen was 1.35mm.

n=10 in each group.

Table 3

Degree of conversion at the bottom surface of 2 mm-thickness specimens (%)

Values are mean(standard deviation)^*.

^*The same superscript letters denote mean values with no statistically significant difference (p>0.01). Duncan grouping was done only within the same time interval.

Thickness of resin specimen was 1.35mm.

n=5 in each group.

Table 4

Knoop Hardness Number at the top surface of 2 mm-thickness specimens

Values are mean(standard deviation)*.

^*The same superscript letters denote mean values with no statistically significant difference (p>0.01). Duncan grouping was done only within the same time interval.

Thickness of resin specimen was 1.35 mm.

n=3 in each group.

Table 5

Knoop Hardness Number at the bottom surface of 2mm-thickness specimens

Values are mean(standard deviation)^*.

^*The same superscript letters denote mean values with no statistically significant difference (p>0.01). Duncan grouping was done only within the same time interval.

Thickness of resin specimen was 1.35 mm.

n=3 in each group.

Table 6

Statistical analysis of microhardness at the top and bottom surfaces

^*Experimental groups are expressed as irradiation mode-exposure time.

^**The same letters denote no statistically significant difference (p>0.01).

Table 7

Microleakage score proportions at enamel margin (%)

Table 8

Microleakage score proportions at dentin margin (%)

Tables & Figures

REFERENCES

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The effect of irradiation modes on polymerization and microleakage of composite resin

J Korean Acad Conserv Dent. 2002;27(2):158-174. Published online March 31, 2002

DOI: https://doi.org/10.5395/JKACD.2002.27.2.158

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The effect of irradiation modes on polymerization and microleakage of composite resin

Fig. 1 Schematic drawing of the Linometer with a composite sample placed between the glass plate and aluminium disk.

Fig. 2 Schematical representation of microleakage scoring system. Score 0: no penetration of dye; 1: penetration of dye into half of the cavity depth; 2: penetration of dye beyond half of the cavity depth; 3: penetration of dye into the cavity floor.

Fig. 3 Volumetric polymerization shrinkage (%). ↑indicates the finishing time (20 sec) of irradiation for OR group. ▴indicates the finishing time (60 sec) of irradiation for V2, V4, V6 and OC groups. Each data represents mean value from 10 specimens.

Fig. 4 Volumetric polymerization shrinkage including VPD group (%). ↑indicates the finishing time (20 sec) of irradiation for OR group. ▴indicates the finishing time (60 sec) of irradiation for V2, V4, V6 and OC groups. ▵indicates the starting time (303 sec) of second irradiation for VPD group. Each data represents mean value from 10 specimens.

Fig. 5 Initial volumetric polymerization shrinkage(%). Each data represents mean value from 10specimens.

Fig. 6 Degree of conversion at the bottom surface of 2mm thickness specimens (%). Each data represents mean value from 5specimens.

Fig. 7 Knoop Hardness Number at the top surface of 2 mm thickness specimens. Each data represents mean value from 3 specimens.

Fig. 8 Knoop Hardness Number at the bottom surface of 2 mm thickness specimens. Each data represents mean value from 3 specimens.

Fig. 9 Microleakage score proportions at enamel margin (%). The data presented are representatives of 30 specimens from V2, 22 specimens from V4, 24 specimens from V6, 24 specimens from OC, 30 specimens from OR and 26 specimens from VPD group.

Fig. 10 Microleakage score proportions at dentin margin (%). The data presented are representatives of 30 specimens from V2, 22 specimens from V4, 24 specimens from V6, 24 specimens from OC, 30 specimens from OR and 26 specimens from VPD group.

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Fig. 8

Fig. 9

Fig. 10

The effect of irradiation modes on polymerization and microleakage of composite resin

Table 1

Various light curing modes used in this study

Table 2

Linear polymerization shrinkage (10^-3mm)

Values are mean(standard deviation)^*.

^*The same superscript letters denote mean values with no statistically significant difference (p>0.01). Duncan grouping was done only within the same time interval.

Thickness of resin specimen was 1.35mm.

n=10 in each group.

Table 3

Degree of conversion at the bottom surface of 2 mm-thickness specimens (%)

Values are mean(standard deviation)^*.

^*The same superscript letters denote mean values with no statistically significant difference (p>0.01). Duncan grouping was done only within the same time interval.

Thickness of resin specimen was 1.35mm.

n=5 in each group.

Table 4

Knoop Hardness Number at the top surface of 2 mm-thickness specimens

Values are mean(standard deviation)*.

^*The same superscript letters denote mean values with no statistically significant difference (p>0.01). Duncan grouping was done only within the same time interval.

Thickness of resin specimen was 1.35 mm.

n=3 in each group.

Table 5

Knoop Hardness Number at the bottom surface of 2mm-thickness specimens

Values are mean(standard deviation)^*.

^*The same superscript letters denote mean values with no statistically significant difference (p>0.01). Duncan grouping was done only within the same time interval.

Thickness of resin specimen was 1.35 mm.

n=3 in each group.

Table 6

Statistical analysis of microhardness at the top and bottom surfaces

^*Experimental groups are expressed as irradiation mode-exposure time.

^**The same letters denote no statistically significant difference (p>0.01).

Table 7

Microleakage score proportions at enamel margin (%)

Table 8

Microleakage score proportions at dentin margin (%)

Table 1 Various light curing modes used in this study

Table 2 Linear polymerization shrinkage (10-3mm)

Values are mean(standard deviation)^*.

^*The same superscript letters denote mean values with no statistically significant difference (p>0.01). Duncan grouping was done only within the same time interval.

Thickness of resin specimen was 1.35mm.

n=10 in each group.

Table 3 Degree of conversion at the bottom surface of 2 mm-thickness specimens (%)

Values are mean(standard deviation)^*.

^*The same superscript letters denote mean values with no statistically significant difference (p>0.01). Duncan grouping was done only within the same time interval.

Thickness of resin specimen was 1.35mm.

n=5 in each group.

Table 4 Knoop Hardness Number at the top surface of 2 mm-thickness specimens

Values are mean(standard deviation)*.

^*The same superscript letters denote mean values with no statistically significant difference (p>0.01). Duncan grouping was done only within the same time interval.

Thickness of resin specimen was 1.35 mm.

n=3 in each group.

Table 5 Knoop Hardness Number at the bottom surface of 2mm-thickness specimens

Values are mean(standard deviation)^*.

^*The same superscript letters denote mean values with no statistically significant difference (p>0.01). Duncan grouping was done only within the same time interval.

Thickness of resin specimen was 1.35 mm.

n=3 in each group.

Table 6 Statistical analysis of microhardness at the top and bottom surfaces