788 final Influence of Different Temperatures on the Polymeriza9on Pre- and Post-Cured of Various Resin Materials Vol 13 No 1 (2025) DOI 10.5195/d3000.2025.788 h#p://den*stry3000.pi#.edu Influence of Different Temperatures on the Polymerization Pre- and Post-Cured of Various Resin Materials Fanar Turki Al-Jadwaa1, Mahammad Munthir Abdurazzaq2, Emad Farhan Alkhalidi1 1 College of Dentistry, University of Mosul, Mosul, Iraq 2 College of Dentistry, Al-Iraqia University, Bagdad, Iraq Abstract Objec&ve: To evaluate and compered the effect of different temperatures (5°C, 37°C and room temp. ±23°C) pre- cured and post-cured for three universal- Chroma composite materials (Hybrid-Nano fillers, Supra-Nano, Nano filler) on the polymerizaHon degree and micro-hardness. Materials: A seventy-five disc-samples-shaped were fabricated from (Omnichroma, ViNra APS, DenFil N), for each test in different temperatures (5°C, 37°C and room temp. ±23°C) were light cured according to manufacture instrucHon. The Fourier trans-form infrared spectroscopy was used to the polymerizaHon degree measured for each sample while the micro-hardness was measured by the using of Vickers hardness test. Data were analyzed using One-Way-Analysis of Variance at level p < 0.05. Results: The analysis showed that there was significant difference in the polymerizaHon degree and in the micro-hardness of the samples fabricated at the different temperatures when heated pre- and post- cured of all materials increase, in the polymerizaHon degree and the micro-hardness of the samples. Conclusions: Increasing three universal- Chroma composite materials (Hybrid-Nano fillers, Supra-Nano, Nano filler) temperature whether pre-cured and post-cured allows for maintaining or increasing polymerizaHon degree and hardness of three universal- Chroma composite materials especially DenWilN Nano- filler composite. Keywords: Temperature, Universal- Chroma composite, Degree of polymerizaHon, Micro- hardness. Cita:on: Al-Jadwaa FT, et al. (2025) Influence of Different Temperatures on the Polymeriza:on Pre- and Post-Cured of Various Resin Materials. Den:stry 3000.1:a001 doi:10.5195/d3000.2025.788 Received: December 4, 2024 Accepted: February 8, 2025 Published: February 12, 2025 Copyright: ©2025 Al-Jadwaa FT, et al. This is an open access ar:cle licensed under a Crea:ve Commons AYribu:on Work 4.0 United States License. Email: Fanarturki@uomosul.edu.iq Introduction Composite resins (CRs) are aesthetic dental-restorative materials that can be placed directly with minimal loss of tooth structure. CRs have become the most widely used posterior tooth fillings [1]. CRs are composed of monomer converted to polymer during polymerization and can be studied with fourier transform infrared spectroscopy technique without changing typical clinical conditions [2,3]. The CR as a direct restoration can be usage facilitated via pre-heating but is still a controversy. CR restorations are technique sensitive and are typically placed and cured in 2mm layers [4,5]. Temperature plays an important role in the polymerization process of CRs [6]. When temperature is higher, it enhances monomer mobility, due to lowered viscosity, with increased degree of conversion [7,8]. Hardness is a property of major importance for assessing the adequate setting and stability of restorative materials [9]. Refrigerating CRs appeared to decrease degree of conversion, requiring more time for curing [10,11]. Higher degree of conversion improves fracture resistance [12]. Heating CRs allow for reduction of curing time and Influence of Different Temperatures on the Polymeriza9on Pre- and Post-Cured of Various Resin Materials Vol 13 No 1 (2025) DOI 10.5195/d3000.2025.788 h#p://den*stry3000.pi#.edu less thickness, which is desirable in deep restorations [13]. The objective of this study was to evaluate and compare the effect of different temperatures (5°C, 37°C and room temperature, ±23°C) in three pre- and post-cured universal- Chroma composite materials (Hybrid-Nano fillers, Supra-Nano, Nano filler). Materials and Methods Table 1 and Figure 1 describe the composite resins used in the study. Specimen Fabrication and distribution Seventy-five samples were prepared and distributed as follows: Group 1: refrigerated samples before curing at 5°C for 24h. Group 2: refrigerated samples after curing at 5°C for 24h. Group 3: pre-heated samples before curing at 37°C for 24h Group 4: heated samples after curing at 37°Cfor 24h Group 5: samples stored at room temperature after curing (±23°C for 24h). All specimens were prepared by condensing the CRs into a polyethylene mold (2mm depth or height and 5mm in diameter) and then the materials were covered with cellulose strip matrix and cover glass slide. After that, specimens were cured via LED-LCU according to manufacture instructions using a digital timer. The LCU tip was placed directly over each sample (without space between them) at the top surface after that was finished and polished (TDV, Brazil) with a low- speed handpiece. Then, samples were put in a dark container in an incubator (Fisher scientific- isotemp/incubator/USA). FTIR (Fourier trans-form infrared spectroscopy) was used to determine the degree of conversion. The spectra of CRs was recorded. The double vinyl bonds are shown by the intensity of the peak (1608-1637 cm-1) referring to the C=C, then degree of conversion (DC) was calculated using the following equation: DC = {(Ao-At)/Ao} *100. where Ao = uncured resin material and At = cured resin-material. Statistical analysis was done using ANOVA. Microhardness was measured with a Vickers diamond indenter attached as Figure 2a. A load was applied over the top of the polished surface of each specimen (300g) for 15 seconds. Two point evenly spaced indentation measurements were made. There was no instance with less than 1 mm between indentations or to the margin of the discs. Measurements were made as the diagonal lengths of the indentation mark made on the surface of each disc. Average values were calculated. The resultant dimensions were measured with the aid of an optical microscope (300 X) (Yamayo Make Tr-200) (Figure 2b). Statistical analysis was performed with SPSS 18 software (IBM Analytics, Armonk, NY, USA), with p < 0.05 considered statistically significant. Influence of Different Temperatures on the Polymeriza9on Pre- and Post-Cured of Various Resin Materials Vol 13 No 1 (2025) DOI 10.5195/d3000.2025.788 h#p://den*stry3000.pi#.edu Figure 1. Materials and fabricated discs used in the study. Figure 2. (a) Vickers diamond (b) indentations of Vickers micro-hardness. a b Influence of Different Temperatures on the Polymeriza9on Pre- and Post-Cured of Various Resin Materials Vol 13 No 1 (2025) DOI 10.5195/d3000.2025.788 h#p://den*stry3000.pi#.edu Material/ Shade Type Manufacture Composition Vittra APS NIQUE / Universal chroma Hybrid-nano fillers FGM, Brazil Matrix: Mixture of methacrylate monomers, UDMA, TEGDMA, photo initiator compound (APS). Fillers: 72-80% by weight, 52-60% by volume boron- aluminum silicate glass. OMNICHROMA/ Universal chroma Supra-nano Tokuyama Dental, Japan Matrix: UDMA, TEGDMA. Fillers: 79% by weight uniform supra-nano spherical filler (SiO2- ZrO2 260 nm). DenFil N / Universal chroma Nano- filler VERICOM, Korea Matrix: BisGMA, TEGDMA Filler content: Barium, aluminosilicate, Fumed silica. Filler: 80% by weight Results Degree of Conversion (DC) Descriptives of DC values of the three tested CRs pre-cured and post- cured at different temperatures (5°C, 37°C, and room temperature, ±23°C) are seen in Table 2. The DC values for the disc Table 1. Materials used in the study. Influence of Different Temperatures on the Polymeriza9on Pre- and Post-Cured of Various Resin Materials Vol 13 No 1 (2025) DOI 10.5195/d3000.2025.788 h#p://den*stry3000.pi#.edu samples pre- and post-cured at 5°C were lower than those for disc samples pre- and post-cured at 37°C or at room temperature. Analysis of variance ANOVA showed that there were significant differences at 37°C. The DC increased pre-and post-cured at 37°C, while there were no significant differences between DC at 5°C (Table 3). Vickers Micro-Hardness (VH) Vickers microhardness (VH) evaluations of the different tested composite materials before and after polymerization at different temperatures are shown in Table 4. The VH values for the disc samples at 5°C were lower than those for specimens at 37°C. This was shown for the three CR types tested with 2 mm thickness, whether pre- or post-cured. Analysis of variance ANOVA showed that there were no significant differences at 37°C of VH of the three CR tested pre- and post-cured (p<0.05). The VH increased at 37°C, while there were no significant differences between VH of the three CR tested at 5°C, whether pre- and post-cured are presented in Table 5. Discussion The study demonstrated the influence of different temperatures on microhardness and DC on universal Chroma CR materials. No clinically relevant differences were found in the temperatures and materials studied. Higher DC and microhardness were reached on the top aspect of samples tested whether pre- or post-cured at 37°C when compared with CRs cured at room temperature. These results may be because higher temperatures will allow for additional polymerization and increased degrees of conversion [14,15]. Influence of Different Temperatures on the Polymeriza9on Pre- and Post-Cured of Various Resin Materials Vol 13 No 1 (2025) DOI 10.5195/d3000.2025.788 h#p://den*stry3000.pi#.edu Table 2. Descriptives the degree of conversion. N Mean Std. Deviation F p- value degree_0f_ conversion at room temp. ±23°C DentfilN 5 46.8000 2.16795 38.160 0.000 Omnichro ma 5 33.0000 5.70088 Vittra 5 53.0000 2.00000 Total 15 44.2667 9.30796 pre_cure_at_37°C DentfilN 5 54.6000 8.56154 0.175 0.842 Omnichro ma 5 52.4000 2.30217 Vittra 5 53.0000 5.70088 Total 15 53.3333 5.71548 post_cure_at_37°C DentfilN 5 71.4000 .89443 89.274 0.000 Omnichro ma 5 82.0000 2.00000 Vittra 5 89.8000 4.08656 Total 15 84.4000 9.87638 pre_cure_at_5°C DentfilN 5 34.2000 7.98123 18.635 0.000 Omnichro ma 5 17.2000 1.78885 Vittra 5 32.4000 1.81659 Total 15 27.9333 9.07482 post_cure_at_5°C DentfilN 5 44.4000 3.64692 152.785 0.000 Omnichro ma 5 46.0000 .70711 Vittra 5 21.4000 2.19089 Total 15 37.2667 11.85909 Influence of Different Temperatures on the Polymeriza9on Pre- and Post-Cured of Various Resin Materials Vol 13 No 1 (2025) DOI 10.5195/d3000.2025.788 h#p://den*stry3000.pi#.edu Table 3. Descriptives the Vickers Micro-Hardness. N Mean Std. Deviation F p-value Vickers micro-hardness at room temp. ±23°C DentfilN 5 72.4200 .50695 2163.804 .0000 Omnichroma 5 47.5400 1.37949 Vittra 5 38.1200 .13038 Total 15 52.6933 14.99788 pre_cure_at_37°C DentfilN 5 71.5600 .25100 2920.686 0.000 Omnichroma 5 47.7800 .80436 Vittra 5 50.2800 .40866 Total 15 56.5400 11.05550 post_cure_at_37°C DentfilN 5 75.0400 .11402 93128.00 0.000 Omnichroma 5 50.6400 .11402 Vittra 5 51.4000 .07071 Total 15 59.0267 11.72534 pre_cure_at_5°C DentfilN 5 40.7800 .16432 4797.748 0.000 Omnichroma 5 33.1400 .08944 Vittra 5 29.5400 .26077 Total 15 34.4867 4.85399 post_cure_at_5°C DentfilN 5 45.8200 .13038 17154.27 3 0.000 Omnichroma 5 37.8800 .04472 Vittra 5 36.5400 .05477 Total 15 40.0800 4.23998 Influence of Different Temperatures on the Polymeriza9on Pre- and Post-Cured of Various Resin Materials Vol 13 No 1 (2025) DOI 10.5195/d3000.2025.788 h#p://den*stry3000.pi#.edu Table 4. Vickers microhardness values of the study. N Mean Standard Deviation Standard Error Vickers microhardness at room temperature (±23°C) DentfilN 5 72.4200 .50695 .22672 Omnichroma 5 47.5400 1.37949 .61693 Vittra 5 38.1200 .13038 .05831 Total 15 52.6933 14.99788 3.87244 Pre-cured at 37°C DentfilN 5 71.5600 .25100 .11225 Omnichroma 5 47.7800 .80436 .35972 Vittra 5 50.2800 .40866 .18276 Total 15 56.5400 11.05550 2.85452 Post-cured at 37°C DentfilN 5 75.0400 .11402 .05099 Omnichroma 5 50.6400 .11402 .05099 Vittra 5 51.4000 .07071 .03162 Total 15 59.0267 11.72534 3.02747 Pre-cured at 5°C DentfilN 5 40.7800 .16432 .07348 Omnichroma 5 33.1400 .08944 .04000 Vittra 5 29.5400 .26077 .11662 Total 15 34.4867 4.85399 1.25330 Post cured at 5°C DentfilN 5 45.8200 .13038 .05831 Omnichroma 5 37.8800 .04472 .02000 Vittra 5 36.5400 .05477 .02449 Total 15 40.0800 4.23998 1.09476 Influence of Different Temperatures on the Polymeriza9on Pre- and Post-Cured of Various Resin Materials Vol 13 No 1 (2025) DOI 10.5195/d3000.2025.788 h#p://den*stry3000.pi#.edu Table 5. One-way ANOVA for Vickers microhardness. F p-value Vickers micro-hardness at room temperature (±23°C) Between Groups 2163.804 0.000 Within Groups Total Pre-cured at 37°C Between Groups 2920.686 0.000 Within Groups Total Post-cured at 37°C Between Groups 93128.000 0.000 Within Groups Total Pre-cured at 5°C Between Groups 4797.748 0.000 Within Groups Total Post-cured at 5°C Between Groups 17154.273 0.000 Within Groups Total Improved flow ability of heated CRs may result in better adaptation to internal walls of deep cavity preparation. Also, curing at higher temperatures might have improved physiomechanical properties of the material [16], and higher microhardness values [15,17]. Our tests were done using accurate (FTIR) and accessible methods (VH) [18,19]. Finally, elevating CR temperature during light curing is caused by both the heat generation from CR polymerization and from the light source. This may lead to pulp tissue damage. However, the blood circulation in Influence of Different Temperatures on the Polymeriza9on Pre- and Post-Cured of Various Resin Materials Vol 13 No 1 (2025) DOI 10.5195/d3000.2025.788 h#p://den*stry3000.pi#.edu the chamber of pulp may play a role in decreasing the temperature induced by the CR polymerization [20]. Conclusions Increasing the temperature of composite resins, whether pre- or post-cured, allows for maintaining or increasing degree of polymerization and hardness. References 1- Siriboina Sirisha, C Vinay, Rama Krishna Alla, KS Uloopi, Penmatsa Chaitanya, Nadella Chandana. Physicomechanical characteristics of Ormocer and Bulk Fill composite resin restorative materials: An in-vitro study. Journal of Clinical and Diagnostic Research, Journal of Clinical and Diagnostic Research. 2023; Vol-17(7): ZC01- ZC04. DOI:10.7860/JCDR/2023/6 2857.18107 2- Fanar T. H. Al-Jadwaa, Moataz GH. S. Al-Shaekh, Amer A. Taqa. The effect of storage media on the degree of conversion of different types of composite resin. Al- Rafidain Dental Journal, the 5th Scientific Conference of Dentistry College. 2011; Special issue :317-322. 3- Norbert Kramer, Ulrich Lohbauer, Franklin Garcia- Godoy, Roland Frankenberger. Light curing of resin-based composites in the LED era. Am J Dent. 2008; 21:135-142. 4- Abdulwahhab ZS, Alkhalidi EF. Effect of staining and bleaching on surface roughness of different nano hybrid resin composite materials. Al–Rafidain Dent J. 2021;21(1):42-50. 5- AlShaafi MM. Effects of Different Temperatures and Storage Time on the Degree of Conversion and Microhardness of Resin- based Composites. J Con temp Dent Pract 2016;17(3):217-223. 6- Calheiros FC, et al. Effect of temperature on composite polymerization stress and degree of conversion. Dent Mater. dental.2014;02.024. http://dx.doi.org/10.1016/j 7- Sultan MA. The effect of various pre-cured temperature of different resin materials on the degree of conversion and microhardness of cured composite resin. Al– Rafidain Dent J. 2014; 14(2):279-287. 8- Trujillo M, Newman SM, Stansbury JW. Use of near- IR to monitor the influence of external heating on dental composite photopolymerization. Dent Mater 2004;20(8): 766-777. 9- Behnam Bolhari, Naghmeh Meraji, Pegah Khazaee, Sholeh Ghabraei, Sara Valizadeh. Do different time intervals in placement of restorative materials over calcium silicate cements, affect interface microhardness of different restorative materials. Dentistry 3000. 2021; 1:a001 doi:10.5195/d3000.2021.1 59 10- Kitzmuller K, Graf A,Watts D, et al. Setting kinetics and shrinkage of self-adhesive resin cements depend on cure-mode and temperature. Dent Mater. 2011; 27:544-51. 11- International Standard 4049. Dentistry-polymer- Influence of Different Temperatures on the Polymeriza9on Pre- and Post-Cured of Various Resin Materials Vol 13 No 1 (2025) DOI 10.5195/d3000.2025.788 h#p://den*stry3000.pi#.edu based filling, restorative and luting materials. Geneva, Switzerland: International Organization for Standardization;200. 12- Trujillo M, Newman SM, Stansbury JW. Use of near- IR to monitor the influence of external heating on dental composite photo polymerization. Dent Mater. 2004; 20:766-77. 13- Holmes RG, Blalock JS, Rueggeberg FA. Composite film thickness at various temperatures. J Dent Res. 2004;83 (Speciel issue A). Abstract 3265. 14- Watts DC, Alnazzawi A. Temperature-dependent polymerization shrinkage stress kinetics of resin- composites. Dent Mater 2014; 30(6):654-660. 15- Myoung Uk Jin, Sung Kyo Kim. Effect of Pre-Heating on Some Physical Properties of Composite Resin. J Kor Acad Cons Dent. 2009; 34(1):30-37. 16- Kurachi C, Tuboy A, Magalhaes S. Hardness evaluation of a dental composite polymerized with experimental LED- based devices. Dent Mater. 2001; 17:309-315. 17- Asmussen E. Restorative resins: Hardness and strength vs. quantity of remaining double bonds. Scand J Dent Res. 1982; 90:484-489. 18- Acquaviva PA, Cerutti F, Adami G, Gagliani M, et al. Degree of conversion of three composite materials employed in the adhesive cementation of indirect restorations: a micro- Raman analysis. J Dent. 2009; 37(8):610-5.doi: 10.1016/j.jdent.2009.04.00 1. 19- Farnaz Farahat, Abdolrahim Davari, Marzieh Fadakarfard. Effect of storage time and composite thickness on Degree of Conversion of Bulk-fill and universal composites using FTIR method. Braz Dent Sci 2020; 23(2). Doi:10.14295/bds.2020.v2 3i2.1915. 20- Fanar T. A.Al-Jadwaa. Effect of different curing times of composite resin and glass ionomer liner use on the pulpal temperature. MDJ. 2022; 1(18):1-7.