991 D3000 new imprint Word template Vol 13, No 1 (2025) ISSN 2167-8677 (online) DOI 10.5195/d3000.2025.991 http://dentistry3000.pitt.edu Evaluation of Surface Roughness of Heat Cured PMMA after Immer- sion in Artificial Saliva and Different Solutions Shurooq Falih Altaie1, Nihad H. Alfuraiji1, Rasha Mohammed Zwyyer2, Enas Shihab Ahmed3 1College of Health and Medical Techniques, Middle Technical University, Baghdad, Iraq 2College of Health and Medical Techniques, University of Bilad Alrafidain, Diyala, Iraq 3College of Den@stry, University of Bilad Alrafidain, Diyala, Iraq Abstract ObjecBve: The aim of this in vitro study was to evaluate the surface roughness of heat-cured acrylic resin aLer immersion in arMficial saliva and different soluMons. Material and Methods: 70-disc shaped specimens 10mm in diameter and 2 mm in thickness were prepared from heat-cured acrylic resin. Then, divided into 2 groups. First group consist of 4 groups as follow: (control) immersion in disMlled water, immersion in Zamzam water, immersion in diluted thyme oil and immersion in mouth wash (Listerine ®) with 10 samples each. The samples were immersed in their respecMve soluMon for 8 h per day for one month. The second group consist of 3 groups as follow disMlled water, arMficial saliva normal and acidic with 10 samples each. The samples kept in arMficial saliva for 16h per day for one month. Profilometer was used to evaluate the surface roughness (µm). For analyzing staMsMcally, the obtained data, one-way ANOVA and LSD test were used. P-value<0.05 was considered significant. Results: All soluMons showed no staMsMcally significant difference on surface roughness of specimens at 8h and 16h for one month. However, the Zamzam water group showed posiMvely signifi- cant difference when immerse 8h for one month. Conclusion: The six soluMons used in this study none produced increased in sur- face roughness compared to control group for two Mmes of immersion Never- theless, the best result as denture cleanser was obtained in Zamzam water which was showed the less value in sur- face roughness (µm). Open Access Cita%on: Altaie SF, et al. (2025) Evalua%on of Surface Roughness of Heat Cured PMMA aDer Immersion in Ar- %ficial Saliva and Different Solu%ons. Den%stry 3000. 1:a001 doi:10.5195/d3000.2025.991 Received: July 15, 2025 Accepted: July 31, 2025 Published: September 9, 2025 Copyright: ©2025 Altaie SF, et al. This is an open access ar%cle licensed under a Crea%ve Commons AUribu%on Work 4.0 United States License. Email: Shurooq.falih@mtu.edu.iq Introduc)on Acrylic resin has been recommended as a denture base material for several years. In addition to having outstanding mechanical qualities, denture base material should ide- ally gain some important physical character- istics, such as biocompatibility and a strong link with prosthetic teeth [1]. Most denture users have poor oral hygiene and struggle to keep their dentures clean. The primary cause of disorders affecting the oral mucosal tis- sues is unclean dentures. Denture wearers were found to have a signiDicant correlation between denture stomatitis and inadequate denture hygiene. For better health, especially in elderly people, edentulous indi- viduals must maintain proper dental hygiene and keep their dentures clean [2]. Dentures can be cleaned mechanically, chemically, or by combining the two [3].The mechanical cleaning procedure is usually used by pa- tients, and it is insufDicient for cleaning un- dercut sections of dentures, which might harbor bacteria. Furthermore, aged patients with weak motor coordination and handi- capped patients with low physical ability and a lack of cooperation may not clear the accu- mulated bioDilm appropriately [4]. The most popular chemical cleaning techniques that have been proposed for prosthesis disinfection are denture cleansers. In addi- tion to being biocompatible, bactericidal, and fungicidal, the best cleaner should also be easy to use and not change the prosthesis's structure in any way. Most importantly, it should effectively remove both organic and inorganic deposits [3]. Long-term use of den- ture cleaners can make PMMA surfaces rougher [5]. The rough, pitted surfaces of acrylic dentures serve as a breeding ground for bacteria to colonize and build bioDilms [3]. The presented in vitro study was con- ducted to evaluate the effect of artiDicial sa- liva and different solutions(distilled water, Zamzam water, diluted thyme oil and mouth EvaluaMon of Surface Roughness of Heat Cured PMMA aLer Immersion in ArMficial Saliva and Different SoluMons Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.991 http://dentistry3000.pitt.edu 2 wash) on surface roughness of heat-cured acrylic resin material. The null hypothesis tested was that no signiDicant differences would be found after immersion in different solutions. Material and Methods Preparation of specimens Metal patterns were constructed [10mm in diameter and 2mm in thickness] [6] . The metal patterns were covered with sepa- rating media and let to dry after the lower part of the dental Dlask was Dilled with dental die stone mixed in accordance with the man- ufacturer's instructions. A layer of separat- ing material was then applied to the whole surface of the stone and the metal patterns after they had been carefully placed to half of their depth and allowed to set. Then, the up- per part of the Dlask was placed on top of the lower part and Dilled with stone. A dental vi- brator was used to remove the trapped air. Following the stone's full setting, the Dlask was opened (see Figure 1), and the metal de- signs were taken out to create a mold for packing heat-cured acrylic resin. Following a 15-minute hydraulic pressure test, the clamped Dlask was placed in a water bath to cure it. It was heated to 74°C for 1.5 hours and then raised to boiling, 100°C, for 30 minutes (ADA, 1999). After the curing pro- cess was Dinished, the Dlask was submerged in water for 15 minutes and allowed to cool gradually at room temperature for 30 minutes [2]. A tungsten steel bur put in a handpiece at low speed was then used to trim only the superDluous acrylic after the acrylic specimens had been carefully re- moved from the stone mold. The specimens' surfaces are left unDinished [1]. Figure 1. Opening the Dlask. Immersion Procedure The specimens were divided into two groups: First group: 40 specimens were distributed into the following: (Control) group of Distal Water, Zamzam water, thyme oil diluted us- ing a 1:1 mixture of thyme essential oil (allin and polysorbate) and distilled water at a concentration of 0.5µl/ml [7], and group of mouth wash (Listerine) each of these solu- tions contained 10 specimens, and 200 ml of the solution were immersed in closed con- tainers [1] once a day for 8 hours to simulate overnight use [8,9]. None of the solutions was replaced during this period [10] for 30 days [11] . Second group: 30 specimens were distrib- uted into the following: ArtiDicial saliva normal and acidic: (Control) 10 specimens were immersed in distilled water,10 specimens were immersed in nor- mal saliva and 10 specimens were immersed in acidic saliva up to 200 ml once a day for 16 hours for 30 days [11] to simulate the time of denture wearing. Surface Roughness Test Each disc-shaped specimen's surface rough- ness was measured to within 0.01 µm using a Time Group Inc. hand-held roughness measurement equipment proDilometer (TR200). The analyzer's stylus traveled 0.5 mm/second across the specimen surface. The recorded data had a resolution of 0.01µm, a cut of value of 0.8mm, and a trac- ing length of 2.4 mm. Each specimen had three readings taken, and the specimen's mean roughness (Ra) was determined [2,12]. Statistical Analysis Statistical package for social science, version 21 (SPSS) was used to gather and analyze the research's data. Surface roughness change was summarized using descriptive statistics, and a one-way analysis of variance (ANOVA) was conducted on surface roughness (µm) and followed by an LSD test for group com- parison. A P value <0.05 was deemed statis- tically signiDicant. Results The result of surface roughness(µm) showed that all group nearly the same mean value for groups control (distil water), diluted thyme oil, mouth wash (2. 5809±.53136 µm), (2.6199±.70094 µm) and (2.8566±.37206 µm) respectively and the lower mean value of surface roughness was for Zamzam water group (1.8930± .26521 µm) after immersion in 8 hours a day for one month as shown in Table 1 and Figure 2. To compare the mean values among groups, least signiDicant differ- ence (LSD) test was implied Table 3. The test showed signiDicant difference when com- pared Zamzam water group with control group (distil water), diluted thyme oil group and mouth wash group, and the test revealed non- signiDicant difference between groups of diluted thyme oil and mouth wash when compared with control group (distil water) also non- signiDicant difference between groups of diluted thyme oil and mouth wash. The surface roughness (µm) for the second group showed nearly the same mean value for all groups control (distil water), ArtiDicial saliva (normal), ArtiDicial saliva (acidic) (2.5809±0.53136 µm), (2.3243±0.40270 µm) and (2.4948±0.63629 µm) respectively after immersion 16 hours a day as shown in Table 4 and Figure 3. Statistical analysis us- ing one-way ANOVA test showed a statisti- cally non- signiDicant difference among the mean values of the study groups as shown in Table 5. Discussion For the acrylic surface to be free of microor- ganisms, surface roughness is crucial [13]. An increase in surface roughness may make bioDilm removal more challenging [14]. In this study, the duration of immersion in the denture cleanser was selected to mimic the 8-hour overnight immersion, which is a typical scenario in which dentists advise pa- tients to take out their dentures while they are asleep and submerge themselves in solu- tions to relieve the underlying tissues and clean the dentures [8]. Based on the results of surface roughness of this study the null hypothesis was accepted. The present study's Dindings demonstrated that, except for the Zamzam water group, which had greater smoothness or less sur- face roughness, overnight immersion pro- duced surface roughness values that were al- most identical (µm). Figure 1 and Table 1.The current study's Dindings concur with Ural C et al. and found no difference in the impact of sodium hypochlorite and commer- cial cleansers on surface roughness [15] agreement with Salem et al., who demon- strated that there is no discernible change in the surface roughness of acrylic resin sam- ples immersed in various denture cleaning solutions as opposed to samples immersed in distilled water [16]. The PH of Listerin® is 4.11. It is reasonable to believe that the increased acidity led to the breakdown of the acrylic resin's outermost layer, which raised the roughness values. A subsurface area of the acrylic resin was re- vealed as a result of the material's ongoing exposure to these mouthwashes, which en- couraged the loss of this outer layer [13]. The plant extract denture cleaner of choice was thyme essential oil. This was consistent with research by Liu et al., which found that thyme essential oil had the lowest inhibitory concentration values and was the best anti- fungal and antimicrobial [17]. Comparing EvaluaMon of Surface Roughness of Heat Cured PMMA aLer Immersion in ArMficial Saliva and Different SoluMons Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.991 http://dentistry3000.pitt.edu 3 the Dittydent to other commercially available denture cleansers, Sharam et al. found that it had the least impact on the surface proper- ties of denture resins. However, when com- pared to the thyme essential oil denture cleanse, it signiDicantly increased the surface roughness [18]. In an acrylic resin denture foundation subjected to glutaraldehyde for ten minutes, Carvalho et al. observed surface pitting and the development of polymer beads [19]. Although there was no signiDicant difference between the groups in this study, there was a signiDicant difference between the Zamzam water group and other solu- tions. According to Al-Ansy et al., bottled Zamzam is ozonated [20]. When ozonated water, an environmentally friendly disinfection solu- tion, was examined for its impact on PMMA's surface roughness and surface less, it was discovered to have no effect [21]. The pa- tient's time wearing the denture is repre- sented by the samples of heat-cured acrylic resin submerged in artiDicial saliva (both normal and acidic) for 16 hours. Resin's characteristics may be compromised by its susceptibility to various environmental con- ditions. Saliva, humidity, and temperature variations are some of these variables. One of the primary issues in the Dield of removable dental prosthesis has been alterations in sal- ivary pH [22]. Alfadda et al. discovered that soaking in neutral and basic PH values con- siderably increased the heat-cured acrylic material's surface roughness [12]. The re- sults of this study disagree with Alfadda et al. Limitation It is well known that depending on the pa- tient's dietary intake, the salivary PH value in the oral cavity continuously Dluctuates be- tween acidic and basic. The same acrylic ma- terial may therefore need to be exposed to different salivary PH levels to examine how it affects surface roughness or other mechan- ical and physical characteristics. Along with other limitations, the current study only ex- amined the effects of various chemical clean- ers on a single type of denture base resin, and the immersion period was only one month. Conclusion Within the limitations and based on the re- sults of this study, it was found that Zamzam water showed less or no negative effect on surface roughness and the mouth wash lis- terin® showed slight increase in surface roughness but a statistically no signiDicant difference when compared with control. In addition, both two types of artiDicial saliva had no effect in increasing of surface rough- ness. Author’s Contribu)on SFA: Methodology, Writing – RMZ: Original Draft Preparation. NH: Supervision. Conflict of Interest We have no conDlicts of interest to disclose regarding this article. The opinions ex- pressed are solely those of the authors and have not been inDluenced by any Dinancial or personal relationships. Regulatory Statement This article did not involve the use of any hazardous materials, living organisms, or any procedures that could harm the environ- ment. There was no need to comply with any speciDic regulatory laws or regulations re- garding occupational health and safety or the environment. All necessary measures were taken to ensure compliance with ethical re- search practices and laboratory safety. References 1. Jasim, S., S.M. Abass. Effect of Alum Disinfectant Solutions on Some Properties of a Heat- Cured Acrylic Resin. J Res Med Dent Sci, 2021. 9(5): p. 42-47. https://www.jrmds.in/articles/effect-of- alum-disinfectant-solutions-on-some-properties- of-a-heatcured-acrylic-resin.pdf 2. Abdallah, R.M., N.S. Aref. An in vitro assessment of physicomechanical properties of heat-cured denture base resin disinfected by ozonized water. World J Dent, 2020. 11(2): p. 146- 150. https://www.wjoud.com/ 3. Jeyapalan, K., J.K. Kumar, N. Azhagarasan. Comparative evaluation of the effect of denture cleansers on the surface topography of denture base materials: An: in-vitro: study. Journal of Pharmacy and Bioallied Sciences, 2015. 7(Suppl 2): p. 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J Bagh Col Dentistry, 2007. 19(1): p. 1-5. https://jbcd.uobaghdad.edu.iq/ 17. Liu, X. et al. Screening of food additives and plant extracts against Candida albicans in vitro for prevention of denture stomatitis. Procedia Environmental Sciences, 2012. 12: p. 1361-1366. DOI: 10.1016/j.proenv.2012.01.421 18. Sharma, P., S. Garg, N.M. Kalra. Effect of denture cleansers on surface roughness and Glexural strength of heat cure denture base resin-an in vitro study. Journal of clinical and diagnostic research: JCDR, 2017. 11(8): p. ZC94. DOI: 10.7860/JCDR/2017/29014.10492 19. Carvalho, C.F. et al. Effect of disinfectant solutions on a denture base acrylic resin. Acta Odontológica Latinoamericana, 2012. 25(3): p. 255-260. https://www.scielo.br/j/aol/a/5L5QH8vXvJkY7k QJQJ5J5QJ/ 20. Al-Ansi, S.A., A.A. Othman, M.A. Al-Tufail. Bromate pollutant in ozonated bottled Zamzam water from Saudi Arabia determined by LC/ICP-MS. Journal of Environmental Science and Health, Part A, 2011. 46(13): p. 1529-1532. DOI: 10.1080/10934529.2011.609082 21. Hamada, M., A. Alam-Eldein, Z. Shorbagy. The effect of ozonised water versus alkaline peroxide cleaners on colour stability, surface roughness and hardness of two different EvaluaMon of Surface Roughness of Heat Cured PMMA aLer Immersion in ArMficial Saliva and Different SoluMons Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.991 http://dentistry3000.pitt.edu 4 denture base materials. Egyptian Dental Journal, 2022. 68(3): p. 2613-2624. http://edj-eg.com/ 22. Tango, R.N. et al. The role of new removable complete dentures in stimulated salivary Glow and taste perception. Journal of Prosthodontics, 2018. 27(4): p. 335-339. DOI: 10.1111/jopr.12605 Table 1. Descriptive statistics of surface roughness (µm) after immersion in different solutions 8 hours a day for one month for all studied groups. Groups N Mean Std. Deviation Std. Error Minimum Maximum Control (distil water) 10 2.5809 0.53136 0.16803 1.82 3.65 Zam zam water 10 1.8930 0.26521 0.08387 1.60 2.24 Diluted thyme oil 10 2.6199 0.70094 0.22166 1.64 3.89 Mouthwash 10 2.8566 0.37206 0.11766 2.44 3.64 Total 40 2.4876 0.59917 0.09474 1.60 3.89 Figure 2. Bar chart showing the mean value of surface roughness (µm) after immersion in different solutions 8 hours a day for all studied groups. Table 2. One-way ANOVA to compare the surface roughness (µm) after immersion in different solutions 8 hours a day between control and experimental groups. ANOVA Sum of Squares df Mean Square F p-value Between Groups 5.159 3 1.720 7.002 0.001* Within Groups 8.842 36 0.246 Total 14.001 39 0.0000 0.5000 1.0000 1.5000 2.0000 2.5000 3.0000 Control (distil water) Zam zam water Diluted thyme oil Mouthwash 2.5809 1.8930 2.6199 2.8566 su rf ac e ro ug hn es s( µm ) Studied groups EvaluaMon of Surface Roughness of Heat Cured PMMA aLer Immersion in ArMficial Saliva and Different SoluMons Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.991 http://dentistry3000.pitt.edu 5 Table 3. Least signiDicant difference for surface roughness(µm) after immersion in different solutions 8 hours a day to compare between all studied groups. (I) Group (J) Groups Mean Differ- ence (I-J) P-value 95% ConZidence Interval Lower Bound Upper Bound Control (distil water) Zam zam water 0.68790* 0.004 0.2384 1.1374 Diluted thyme oil -0.03900 0.861 -0.4885 0.4105 Mouthwash -0.27570 0.222 -0.7252 0.1738 Zam zam water Diluted thyme oil -0.72690* 0.002 -1.1764 -0.2774 Mouthwash -0.96360* 0.000 -1.4131 -0.5141 Diluted thyme oil Mouthwash -0.23670 0.293 -0.6862 0.2128 Table 4. Descriptive statistics of surface roughness(µm) after immersion in different solutions 16 hours a day for one month for all studied groups. Figure 3. Bar chart showing the mean value for surface roughness(µm) after immersion in different solutions 16 hours a day for all studied groups. 2.15 2.2 2.25 2.3 2.35 2.4 2.45 2.5 2.55 2.6 Control (distil water) Artificial saliva (normal) Artificial saliva(acidic) 2.5809 2.3243 2.4948 su rf ac e ro ug hn es s( µm ) Studied groups Groups N Mean Std. Deviation Std. Error Minimum Maximum Control (distil water) 10 2.5809 0.53136 0.16803 1.82 3.65 ArtiZicial saliva (normal) 10 2.3243 0.40270 0.12734 1.84 2.92 ArtiZicial saliva(acidic) 10 2.4948 0.63629 0.20121 1.92 3.69 Total 30 2.4667 0.52475 0.09581 1.82 3.69 EvaluaMon of Surface Roughness of Heat Cured PMMA aLer Immersion in ArMficial Saliva and Different SoluMons Vol 13, No 1 (2025) DOI 10.5195/d3000.2025.991 http://dentistry3000.pitt.edu 6 Table 5. One-way ANOVA to compare the surface roughness(µm) after immersion in different solutions 16 hours a day between control and experimental groups. ANOVA Sum of Squares df Mean Square F p-value Between Groups 0.341 2 0.171 0.602 0.555 Within Groups 7.644 27 0.283 Total 7.985 29