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Temperature changes under demineralized dentin during polymerization of three resin-based restorative materials using QTH and LED units.

Mousavinasab SM, Khoroushi M, Moharreri M, Atai M - Restor Dent Endod (2014)

Bottom Line: Light-curing of resin-based materials (RBMs) increases the pulp chamber temperature, with detrimental effects on the vital pulp.The temperature rise under demineralized dentin during Filtek P90 polymerization exceeded the threshold value (5.5℃), with no significant differences between the DCs of the test materials (p > 0.05).Although there were no significant differences in the DCs, the temperature rise under demineralized dentin disks for the silorane-based composite was higher than that for dimethacrylate-based restorative materials, particularly with QTH LCU.

View Article: PubMed Central - PubMed

Affiliation: Torabinejad Dental Research Center and Department of Operative Dentistry, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.

ABSTRACT

Objectives: Light-curing of resin-based materials (RBMs) increases the pulp chamber temperature, with detrimental effects on the vital pulp. This in vitro study compared the temperature rise under demineralized human tooth dentin during light-curing and the degrees of conversion (DCs) of three different RBMs using quartz tungsten halogen (QTH) and light-emitting diode (LED) units (LCUs).

Materials and methods: Demineralized and non-demineralized dentin disks were prepared from 120 extracted human mandibular molars. The temperature rise under the dentin disks (n = 12) during the light-curing of three RBMs, i.e. an Ormocer-based composite resin (Ceram. X, Dentsply DeTrey), a low-shrinkage silorane-based composite (Filtek P90, 3M ESPE), and a giomer (Beautifil II, Shofu GmbH), was measured with a K-type thermocouple wire. The DCs of the materials were investigated using Fourier transform infrared spectroscopy.

Results: The temperature rise under the demineralized dentin disks was higher than that under the non-demineralized dentin disks during the polymerization of all restorative materials (p < 0.05). Filtek P90 induced higher temperature rise during polymerization than Ceram.X and Beautifil II under demineralized dentin (p < 0.05). The temperature rise under demineralized dentin during Filtek P90 polymerization exceeded the threshold value (5.5℃), with no significant differences between the DCs of the test materials (p > 0.05).

Conclusions: Although there were no significant differences in the DCs, the temperature rise under demineralized dentin disks for the silorane-based composite was higher than that for dimethacrylate-based restorative materials, particularly with QTH LCU.

No MeSH data available.


Schematic representation of the temperature rise measurement during polymerization of the resin material under the dentin disc.
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Figure 2: Schematic representation of the temperature rise measurement during polymerization of the resin material under the dentin disc.

Mentions: A K-type thermocouple wire with a diameter of 0.1 cm (ST-8891E, Standard Instruments Co., Ltd., Kowloon, Hong Kong) was connected to a data logger (Standard, ST-8891E, Taiwan) during the light-curing of the resin materials (Figure 2).6 The data logger recorded temperature variations at a rate of 1 sample/second from the start of light-curing to almost 120 - 180 seconds until the temperature decreased. The data were recorded and stored in a computer. The mean of ten readings of the temperature rise was calculated at a pre-determined light output energy at a distance of 3.5 mm from the thermocouple when the light guide tip was secured in place on the mold. The difference between the initial and the peak temperature readings was determined, and the 10 recorded temperature changes were averaged to arrive at the mean temperature rise value. In addition, the temperature rise under a dentin disk during irradiation was measured for simulating the temperature rise in the pulp chamber in clinical situations (Figure 2). The LCU tip was adjusted at the center of each resin material with no gaps in between.


Temperature changes under demineralized dentin during polymerization of three resin-based restorative materials using QTH and LED units.

Mousavinasab SM, Khoroushi M, Moharreri M, Atai M - Restor Dent Endod (2014)

Schematic representation of the temperature rise measurement during polymerization of the resin material under the dentin disc.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4125578&req=5

Figure 2: Schematic representation of the temperature rise measurement during polymerization of the resin material under the dentin disc.
Mentions: A K-type thermocouple wire with a diameter of 0.1 cm (ST-8891E, Standard Instruments Co., Ltd., Kowloon, Hong Kong) was connected to a data logger (Standard, ST-8891E, Taiwan) during the light-curing of the resin materials (Figure 2).6 The data logger recorded temperature variations at a rate of 1 sample/second from the start of light-curing to almost 120 - 180 seconds until the temperature decreased. The data were recorded and stored in a computer. The mean of ten readings of the temperature rise was calculated at a pre-determined light output energy at a distance of 3.5 mm from the thermocouple when the light guide tip was secured in place on the mold. The difference between the initial and the peak temperature readings was determined, and the 10 recorded temperature changes were averaged to arrive at the mean temperature rise value. In addition, the temperature rise under a dentin disk during irradiation was measured for simulating the temperature rise in the pulp chamber in clinical situations (Figure 2). The LCU tip was adjusted at the center of each resin material with no gaps in between.

Bottom Line: Light-curing of resin-based materials (RBMs) increases the pulp chamber temperature, with detrimental effects on the vital pulp.The temperature rise under demineralized dentin during Filtek P90 polymerization exceeded the threshold value (5.5℃), with no significant differences between the DCs of the test materials (p > 0.05).Although there were no significant differences in the DCs, the temperature rise under demineralized dentin disks for the silorane-based composite was higher than that for dimethacrylate-based restorative materials, particularly with QTH LCU.

View Article: PubMed Central - PubMed

Affiliation: Torabinejad Dental Research Center and Department of Operative Dentistry, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.

ABSTRACT

Objectives: Light-curing of resin-based materials (RBMs) increases the pulp chamber temperature, with detrimental effects on the vital pulp. This in vitro study compared the temperature rise under demineralized human tooth dentin during light-curing and the degrees of conversion (DCs) of three different RBMs using quartz tungsten halogen (QTH) and light-emitting diode (LED) units (LCUs).

Materials and methods: Demineralized and non-demineralized dentin disks were prepared from 120 extracted human mandibular molars. The temperature rise under the dentin disks (n = 12) during the light-curing of three RBMs, i.e. an Ormocer-based composite resin (Ceram. X, Dentsply DeTrey), a low-shrinkage silorane-based composite (Filtek P90, 3M ESPE), and a giomer (Beautifil II, Shofu GmbH), was measured with a K-type thermocouple wire. The DCs of the materials were investigated using Fourier transform infrared spectroscopy.

Results: The temperature rise under the demineralized dentin disks was higher than that under the non-demineralized dentin disks during the polymerization of all restorative materials (p < 0.05). Filtek P90 induced higher temperature rise during polymerization than Ceram.X and Beautifil II under demineralized dentin (p < 0.05). The temperature rise under demineralized dentin during Filtek P90 polymerization exceeded the threshold value (5.5℃), with no significant differences between the DCs of the test materials (p > 0.05).

Conclusions: Although there were no significant differences in the DCs, the temperature rise under demineralized dentin disks for the silorane-based composite was higher than that for dimethacrylate-based restorative materials, particularly with QTH LCU.

No MeSH data available.