1004 D3000 new imprint Word template Vol 13, No 1 (2025) ISSN 2167-8677 (online) DOI 10.5195/d3000.2025.1004 http://dentistry3000.pitt.edu Impact of Sinalized Silicon Carbide Nanoparticles on the Physical Characteristics of a Heat-Cured Acrylic Soft Liner Zeena Majid Abdul Amir, Ghasak Husham Jani College of Den*stry, University of Baghdad, Iraq Abstract Objec9ve: The purpose of this research was to examine how adding salinized silicon carbide Np to the soO denture lining material affected its thermal conducQvity, water sorpQon, and solubility. Material and Methods: Silicon carbide NPs were added to the heat-cured soO lin- ing material at quanQQes of 0.4%, and 0.6% by weight. The sixty specimens have been gen- erated in compliance with the prescribed tests. Results: When compared to control speci- mens, soO lining material with 0.6% and 0.4% wt. sic NP had a highly significant decrease in solubility, a non-significant increase in thermal conducQvity, and a non-significant decrease in water absorpQon. Conclusion: The addiQon of silicon carbide nanoparQcles into heat cured acrylic denture soO liner material improved thermal conducQvity and decrease water sorp- Qon and solubility. Open Access Cita%on: Amir MAA, et al. (2025) Impact of Sinalized Sili- con Carbide Nanopar%cles on the Physical Characteris- %cs of a Heat-Cured Acrylic SoG Liner. Den%stry 3000. 1:a001 doi:10.5195/d3000.2025.1004 Received: July 28, 2025 Accepted: July 31, 2025 Published: September 9, 2025 Copyright: ©2025 Amir MAA, et al. This is an open access ar%cle licensed under a Crea%ve Commons AVribu%on Work 4.0 United States License. Email: zeenaalkabi555@gmail.com Introduc)on Dentists have been using soft denture liners for almost a century, with natural rubber be- ing the 9irst [1]. Resilient denture liners can 9ix the problem of dentures becoming ill-9itting from resid- ual ridge resorption, which causes discom- fort and agony to the patient, while retention is necessary for effective dentures [2]. For complete dentures to be comfortable, 9lexible lining materials must be used. For example, if a patient has thin, non-pliable mucosal tissue covering their irregular alve- olar margin, chewing forces applied through a solid acrylic base could be painful. By using soft lining materials, this pain could be alle- viated, and the patient would be more likely to accept their dentures [3,4]. The soft lining materials consist of a variety of synthetic and natural substances, includ- ing hydrophilic polymers, silicone rubber, polyphosphazine 9luoropolymers, 9luoroeth- ylene, and silicones added to polyvinyl silox- ane. Silicone rubber and plasticized acrylics are the two most popular types of soft liners, and they are activated either by heat or chemicals [5]. To be ideal, soft denture liners should exhibit certain properties to ensure a maximum bene9it for denture wearers; among these properties are the biocompatibility, dimen- sional stability, good resiliency, softness, proper wettability, color stability, low water solubility, suf9icient bond strength with the underlying denture base and the ability to in- hibit or reduce the microbial growth [6]. The patient's level of satisfaction with their dentures is affected by the soft denture lin- ers' inability to adequately transfer heat from the denture base to the oral mucosa, Furthermore, the parotid gland's secretion and the health of the underlying supporting tissues are signi9icantly impacted by the den- ture base's poor heat conductivity [7,8]. Soft lining materials have a lot of issues with water solubility and sorption. With time, the plasticizers and other important ingredients in the material will leach out, creating space for other particles and water to enter. This changes the material's chemical structure and physical properties [9]. Due to the gradual loss of plasticizer, the modulus of elasticity of soft-liner material would rise; consequently, its resilience, an essential property, will be compromised. In addition, the epithelial tissue may have a negative response to the release of some plasticizers, such phthalate ester [10]. Silicon carbide is a great material for struc- tural and functional materials due to its high mechanical strength, minimal friction, chem- ical stability, and outstanding thermal con- ductivity [11]. Impact of Sinalized Silicon Carbide NanoparQcles on the Physical CharacterisQcs of a Heat-Cured Acrylic SoO Liner Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.1004 http://dentistry3000.pitt.edu 2 Nanoparticles' exceptional physical features, including high-9lexibility, enhanced strength, and ease of form replication, have garnered a lot of interest for their incorporation into polymer-matrices [12]. Without using dispersing agent, inorganic particles are not easily distributed in polar organic matrix. For this reason, to produce stable chemical bonds with both inorganic and organic materials silane coupling agents are often used. So, the silane function as ad- hesion promoter that is to improve the bind- ing of nanoparticles to the matrix of polymer [13]. Material and Methods Silicon Carbide Surface Modi1ication The nanoparticles of silicon carbide (SiC, Beta, 99.9% purity, less than 80 nm, cubic, Nanoshel, USA) were treated with a silane coupling agent (trimethoxysilylprpoyl meth- acrylate TMSPM Cheng du micxy chemical co. ltd. 2530-86-0. China) to enhance their binding to the polymer matrix and to intro- duce reactive groups into the nanoparticles. Typical process as followed, 30g of nanopar- ticles and 200 milliliters pure toluene were placed into a 9lask then sonicated at ambient temperature for 20 minutes. The standard procedure involved adding 30 grams of na- noparticles to 200 milliliters of pure toluene in a 9lask and sonicating the mixture at room temperature for 20 minutes. Twenty hours were spent drying the modi- 9ied nano 9iller in a vacuum oven set at 60°C. The nano9iller is thereafter left at room tem- perature until it is needed [14,15]. By examining the distinctive vibrations of functional groups, the FTIR spectrophotom- eter can identify if MPS functional groups are bonded to nanoparticles [16]. Preparation of Specimens The soft denture liner material was made of heat-cured acrylic and was sourced from Moonstar in Turkey. Nanoparticles of silicon carbide were included into the soft liner's liquid component. Results from the pilot investigation indicated that concentrations of silicon carbide NPs between 0.4% and 0.6% produced the best shear bond strength and hardness increases. The monomer was combined with the meas- ured amount of nano SiC to form the dough with the correct quantity of nano9iller. The nanoparticles were then uniformly dis- persed throughout the monomer by use of a probe sonication equipment operating at 120 W and 60 KHz for a duration of three minutes [17]. The manufacturer's instructions required the creation of acrylic specimens; thus, a new plastic design was made. The mold was then constructed following the standard proce- dure for making full dentures. Experimental Groups - control group without addition of nanopar- ticles (n=10, for each test). - experimental group with 0.4 % wt. Sci na- noparticles (n=10, for each test). - experimental group with 0.6 % wt. Sci na- noparticles (n=10, for each test). Evaluation of Thermal Conductivity Disks with 40 mm diameters and 5 mm thicknesses have been manufactured for thermal property testing in accordance with instrument standards ISO 22007-2. The specimens were subjected to thermal conductivity testing using the hot disk ther- mal analyzer (Tps 500, Kiteley, Sweden), which uses a double spiral design that ex- tends from a thick sheet of nickel foil. Once the polymer parameter is selected, the sys- tem may be tested with a thermal conductiv- ity value 15 minutes after the hot disk is turned on, which should be done around 1 hour before to the testing. Evaluation of Water Sorption and Solubil- ity The dissecator was used to dry the speci- mens using recently dried silica gel. After be- ing incubated at 37°C ±2 °C for 24 hours, the specimens were allowed to cool to ambient temperature for an additional hour. After- wards, they were precisely weighed using a digital scale, which had an accuracy of (0.000lg). After 9ive days of this, we obtained a constant mass "conditioned mass" (M1), which indicates that the weight loss from each disc was less than 0.2 mg in 24 hours (ADA Speci9ication NO.12, 2000). Following a 7-day immersion in distilled water at 370C ± 2.0C, the specimens were taken out of the water using tweezers and dried with a clean, dry hand towel for 30 seconds. After that, they were permitted to air for 15 seconds be- fore being weighed; the resulting value rep- resents M2. As was done before for the sorp- tion test, the discs were reconditioned to a constant mass in the desiccators at 37°C ±2 °C to get the solubility value; this time, the re- conditioned mass was recorded as (M3). Within 9ive days, the entire group arrived at M3. The following equations were used to calculate the solubility and water sorption: Water sorption = (M2 – M1) / S Water solubility= (M1- M3) / S M1=initial weight of specimen M2=weight after specimen immersion in wa- ter M3=weigh after specimen placed in desicca- tors S=surface area Atomic Force Microscopy (AFM) Analysis The surface topography and morphology of specimens with 0%, 0.4%, and 0.6% concen- trations were examined using atomic force microscopy. The prepared specimens were identical to the hardness test specimens in terms of dimensions (35 mm wide and 6 mm deep). Results Investigating the Properties of Nano- 1illers Made of Silanized Silicon Carbide (SiC) As shown in Figure 1, it is demonstrated that the FTIR result of Sic after silanization dis- plays the same absorption peaks as Sic be- fore salinization. This indicates that the Sic nanoparticles and the silane coupling agent do not form a chemical connection. Figure 2 displays the two- and three-dimen- sional pictures captured by the AFM investi- gation. The two- and three-dimensional im- ages of all have shown unevenly distributed granular 9ilms with large diameters of protu- berances. Grain number and average rough- ness have increased after nanoparticles ad- dition when compared to untreated speci- mens. Results for both the untreated and treated samples were compared in terms of thermal conductivity, water sorption, and water sol- ubility. To establish the importance of adding Sci NPs to acrylic soft-liner specimens, descrip- tive statistics and one-way ANOVA were used to conduct comparative analysis for each group. Table 1 displays the results of the thermal conductivity test, which showed a high mean value in the 0.6% wt. Sci NP group and a sta- tistically non-signi9icant rise in the one-way ANOVA across all groups (p>0.05). Water sorption test results reveal a non-signi9icant decrease in water sorption when comparing all groups in a one-way ANOVA with a p- value of more than 0.05. The water solubility showed a statistically signi9icant reduction in water solubility when comparing all groups in a one-way ANOVA with a signi9icance level of p<0.05. Discussion The use of denture lining materials has grown in signi9icance in the 9ield of dental prosthetics due to the following reasons: in- creased patient comfort, more uniform force distribution, less localized pressure, and bet- ter denture retention for patients whose numbers are projected to rise over the next 20 years [18]. Results from integrating sic NP into PEMA were assessed in this study. A study was Impact of Sinalized Silicon Carbide NanoparQcles on the Physical CharacterisQcs of a Heat-Cured Acrylic SoO Liner Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.1004 http://dentistry3000.pitt.edu 3 conducted to examine the physical features of the soft liner, including its heat conductiv- ity, water sorption, and solubility. A material's thermal conductivity may be de- 9ined as its capacity to evaluate the rate of heat transfer over a certain period in a spe- ci9ic cross-sectional area of the material sam- ples [19]. Poor thermal conductivity is a major concern with poly ethyl methacrylate (PEMA) resin, which impacts both the patient's acceptance of the prosthesis and the health of the tissues supporting the denture [19]. The thermal conductivity reveals a non-sig- ni9icant increase of 0.4% and 0.6% with the introduction of sic NPs into PEMA. This may happen because of particles coming into touch with one another over time, creating a network like a structure known as thermal pathways. These routes facilitate the transfer of heat from one area of the sample to another, ef- fectively bridging the insulating effect of the polymer. Solubility and water sorption were assessed concurrently by measuring the amount of water gained or lost by soluble components [20]. The bonding strength of the liner-denture base contact weakens because the water sorption by the lining material causes changes in dimension and stress concentra- tion. How much water a polymer absorbs de- pends on the 9iller and how it bonds to the polymer. Incorporating silicon carbide NPs into soft denture liner at the concentrations of 0.4% and 0.6% utilized in this research reduced the water sorption mean value, while the ef- fect was not statistically signi9icant. Adding sci NPs may have reduced the number of PEMA molecules on the specimen's surface, which in turn reduced water diffusion. The hydrophobic property of Sci aids in min- imizing the in9iltration of water into the pol- ymer. Another possibility is that the microporosity that forms during polymerization makes it easier for the polymer to absorb 9luids. Be- cause of their 9iller properties, the inclusion of Sci NPs reduced the water sorption by de- creasing the size of these spaces. This study found that adding 0.4%, 0.6% Sic NPs signi9icantly reduced water solubility compared to the control group. This might be because the soft lining material's water sorp- tion characteristics decreased as the amount of Sci NPs increased. Because of this re- striction in the dispersed water, molecular 9lexibility and the extraction of soluble com- ponents from the polymer mass are less likely to occur. Another possible explanation is that the sol- ubility in this study was measured by the loss of specimen weight. Since Sci NPs are insolu- ble in water, they added mass to the speci- mens and acted as impurities, reducing their solubility mean value. This could explain why there was a decrease in solubility mean value as the amount of Sic NPs increased. Conclusion According to the study's criteria, adding sci NPS to soft liner material can improve its heat conductivity, minimize water sorption, and make it less soluble. Funding No speci9ic grant was given to this research by funding organizations in the public, pri- vate, or not-for-pro9it sectors. 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J Bagh Coll Dent [Internet]. 2015 Jun. 15 [cited 2024 Sep. 30];27(2):17-23. Impact of Sinalized Silicon Carbide NanoparQcles on the Physical CharacterisQcs of a Heat-Cured Acrylic SoO Liner Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.1004 http://dentistry3000.pitt.edu 4 Table 1. Thermal conductivity, water sorption and solubility. Thermal conductiv- ity Test groups N Mean Std. Deviation p-value 0% 10 0.1909 0.01296 0.4% 10 0.1915 0.04040 0.6% 10 0.1987 0.03562 total 30 0.5811 0.08898 0.833 Water sorption 0% 10 2.09 11.72 0.4% 10 1.63 4.12 0.6% 10 0.31 5.40 total 30 4.03 21.24 0.082 Water solubility 0% 10 16.35 24.40 0.4% 10 10.39 35.21 0.6% 10 6.22 22.82 total 30 32.96 82.43 0.021 Figure 1. FTIR spectrum of silicon carbide nanoparticles (A) before surface modi9ication and (B) after surface modi9ication. A B Impact of Sinalized Silicon Carbide NanoparQcles on the Physical CharacterisQcs of a Heat-Cured Acrylic SoO Liner Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.1004 http://dentistry3000.pitt.edu 5 e A B C D Impact of Sinalized Silicon Carbide NanoparQcles on the Physical CharacterisQcs of a Heat-Cured Acrylic SoO Liner Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.1004 http://dentistry3000.pitt.edu 6 Figure 2. AFM (atomic force microscopy) and three-dimensional images of (A+B) control specimens, (C+D) 0.4% specimens, and (E+F) 0.6% specimens. E F