Effect of pre-heating on some physical properties of composite resin

Jin, Myoung Uk; Kim, Sung Kyo

doi:10.5395/jkacd.2009.34.1.030

Cited by 4 publications

(2 citation statements)

References 26 publications

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“…This process will determine the end result of polymerisation. 26 Preheating can increase the mobility of polymer chain molecules, delay diffusion reactions and increase the degree of conversion. 11 The number of monomers will decrease with the increase in preheating temperature.…”

Section: Discussionmentioning

confidence: 99%

The different effects of preheating and heat treatment on the surface microhardness of nanohybrid resin composite

2020

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Background: A composite resin is used as restorative material in dentistry because it has the same colour as dental enamel, is easy to use in an oral cavity and offers good biocompatibility. Based on the size of filler, composite resin is divided into types, one of which is a composite resin nanohybrid. An important mechanical property of restorative material is microhardness. The mechanical properties of restorative material is highly affected by both polymerisation and heating process. There are many methods to improve composite resin’s microhardness, including preheating and heat treatment. Purpose: The purpose of this study was to evaluate different effects of preheating and heat treatment on the microhardness of nanohybrid composite resin. Methods: This study is an experimental laboratory research with post-test-only group design. Samples were divided into six groups: preheating groups at temperatures of 37oC and 60oC, heat treatment groups at temperatures of 120oC and 170oC, a negative control group and a positive control group. Afterwards, the resulting data were analysed using one-way ANOVA. Results: The result based on the one-way ANOVA test indicated that there was a difference in microhardness in each group with a significance of 0.000 (p<0.005) between preheating and heat treatment. Conclusion: The conclusion of this study was the best microhardness of composite resin nanohybrid is the heat treatment group at temperature 170oC.

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Section: Discussionmentioning

confidence: 99%

The different effects of preheating and heat treatment on the surface microhardness of nanohybrid resin composite

2020

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“…Moreover, the temperature increase could result in higher crosslinked polymer network or oligomeric network formation [13,18]. Another explanation could be related to the effect of temperature increase in reducing the rate of the polymerization process before reaching the final degree of conversion; therefore less unreacted residual monomer remains free accordingly it leads better mechanical properties [30,48]. Preheating of resin-based materials prior to their use, will lower their viscosity and help in the handling properties, this will lead to better adaptation to cavity walls [49].…”

Section: Dentistrymentioning

confidence: 99%

Influence of storage temperature on vickers microhardness of resin composite

AlMozainy¹

2018

aedj

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Introduction: The purpose of this study is to evaluate the effect of three storage temperatures on microhardness of high and low viscosity bulk-fill materials and compare them with conventional resin-based composite materials. Materials and method: Six composite resin-based materials were used in this study (TN, TNB, TNF, FZ250, FB and FBF) samples were subdivided into three groups based on the pre-curing storage temperature (5°C, 23°C and 37°C). Light polymerization for each material was performed based on the manufacturer's recommendation using Bluephase G2 curing unit (Ivoclar Vivadent, Schaan, Liechtenstein) in a high-intensity mode with an irradiance of 1200 mW/cm 2. Vickers hardness values of top and the bottom surfaces of each sample were evaluated using (NOVA 130 series, Vickers and Knoop hardness testing instrument) under a 200 g load with a dwell time of 10 sec. Also three indentations with the random distance of 1 mm were taken from the top and the bottom surfaces of each sample and a mean Vickers hardness (VHN) value were calculated (n=18 top and n=18 bottom). The mean bottom/top ratio was calculated by dividing VHN of the bottom surface by VHN of the top surface. Results: When the tested materials were stored at room temperature (23°C) before testing in the present study, they failed to reach the minimum 80% of the mean bottom to top hardness value ratio except for FZ250 and FBF, where they reached 97.8% and 83.2% respectively. Where in samples that were stored refrigerated at 5°C all the materials have reached the minimum 80% of the mean bottom to top hardness value ratio except for FBF (77.3%) and TB (77.2%). On the other hand, the only material that reached the minimum 80% of the mean bottom to top hardness value ratio when the materials were stored at 37°C was FZ250 (93.5%). Conclusion: Despite the promising results from this preliminary study, regarding improvement of microhardness with refrigerated composite resins, further research has to be conducted. The enhancement of hardness values associated with preheated composites could be beneficial in countries with warm climate such as Saudi Arabia. The association of precooled composite resin and the use of the LED curing units could be recommended to improve resin-based composite hardness. Further research is needed to evaluate the other mechanical properties and whether or not they are influenced by storage temperature.

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Effect of Preheating on Microleakage and Microhardness of Composite Resin (An in Vitro Study)

L²,

A³

2016

Alexandria Dental Journal

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INTRODUCTION: advancements in composite restorations have been suggested, including preheating of composite resins before photo polymerization by a heating device. OBJECTIVE: The aim of the study was to investigate the effect of preheating before curing on microleakage and microhardness of composite resins. MATERIALS AND METHODS: thirty extracted human molars were used for microleakage assessment. Sixty class V cavities were made in the buccal and lingual surfaces of teeth, and were randomly divided into three groups according to temperature of composite (Group I: 10 °C, Group II: 24°C, and Group III: 54-60°C). Each group is further divided into two subgroups according to the type of composite (nanohybrid composite (Grandio Voco Germany), and microhybrid composite (Z250 3M Espe), where subgroups (IA, IIC and IIIE received nanohybrid composite), and subgroups (IB, IID and IIIF received microhybrid composite). Microleakage was determined by dye penetration test with scoring criteria from (0-3).sixty composite discs were used in vickers microhardness test (VHN),with same experimental grouping as used in microleakage assessment. VHN was determined using calibrated Vickers indenter. Data were collected, tabulated and statistically analyzed by using ANOVA F-test and Chi-square test (p<0.05). RESULTS: concerning microleakage ; there was no significant difference between the groups. The cervical margins showed more microleakage than the occlusal margins. The least microleakage was obtained in subgroup IIIE with mean 0.5 ± 1.08 in 80% of specimens occlusaly and, also IIIE showed the least microleakage in 50% of cases with mean 1 ± 1.25 cervically. Concerning top microhardness; subgroups IA obtained the highest mean top VHN 113.35 ±10.1 followed by subgroup IIIE 108.43 ±1.52.While regarding bottom microhardness subgroup IIC obtained the highest mean bottom VHN 88.49± 1.29, followed by subgroup IA with mean value85.49 ± 9.69. CONCLUSION: it was concluded that preheating enhanced microhardness of composite resin materials, but have no effect on microleakage.

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Effect of pre-heating on some physical properties of composite resin

Cited by 4 publications

References 26 publications

The different effects of preheating and heat treatment on the surface microhardness of nanohybrid resin composite

The different effects of preheating and heat treatment on the surface microhardness of nanohybrid resin composite

Influence of storage temperature on vickers microhardness of resin composite

Effect of Preheating on Microleakage and Microhardness of Composite Resin (An in Vitro Study)

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