Effect of Smoking and Finishing and Polishing Protocol on Color Stability and Surface Roughness of Resin Composite

Effect of Smoking and Finishing and Polishing Protocol on Color Stability and Surface Roughness of Resin Composite | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Effect of Smoking and Finishing and Polishing Protocol on Color Stability and Surface Roughness of Resin Composite Mohamed Samy Salama, Sara Adel Botros, Fatma Makkeyah, Mohamed Shamel, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6163357/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 05 Dec, 2025 Read the published version in BMC Oral Health → Version 1 posted 12 You are reading this latest preprint version Abstract Purpose To investigate the influence of smoking and finishing and polishing protocol on color stability and surface roughness of resin composite. Materials and Methods Seventy-two discs fabricated from supra-nanofilled composite were divided to 6 groups according to: Tobacco Product (Conventional Cigarette/CS and Heated Tobacco/HTP); and Finishing and Polishing Protocol (Control/C, Multi-step finishing system/FS, and Medium-grit abrasive bur + two-step polishing system/PS). After finishing and polishing, specimens were exposed to total 600 cigarettes, divided to 20 each day, simulating 30 days of smoking. Color parameters were detected using a spectrophotometer. Surface roughness (Ra) was measured before and after smoking exposure using a surface roughness tester. Surface morphology was assessed under SEM. Data were analyzed using ANOVA/Tukey's and student t-test. Results For CS, ∆E values of C group was significantly higher than both finishing/polishing groups, which were statistically similar. For HTP, no significant difference in ∆E values between all groups. ∆E values of CS were significantly higher than HTP in all groups. For CS, C group showed significantly higher change in Ra than FS group; whilst no significant difference in Ra change values of PS and those of C and FS groups. For HTP, no significant difference in Ra change between all groups. Within C group, Ra change of both smoking groups was statistically similar. Within FS and PS groups, change in Ra of HTP was significantly higher than CS. Conclusion Conventional cigarette smoking resulted in pronounced color change in composite. While, heated tobacco product produced an increased surface roughness. Both multi-step finishing system and two-step polishing system displayed comparable color change and surface roughness in composite. Smoking Cigarettes Heated Tobacco Product Finishing and Polishing Color Stability Surface Roughness Resin Composite Figures Figure 1 Figure 2 Figure 3 Introduction Tooth discoloration is one of the chief esthetic concerns as it influences the physical and social appeal of the patient. Particularly, smokers’ teeth tend to develop tobacco stains resulting in tooth discoloration and restoration staining.[ 1 ] Tooth discoloration is classified as intrinsic or extrinsic discoloration, where extrinsic staining are caused by external factors that adhere to the tooth surface, like tobacco stains.[ 2 ] The color change of restorations following smoking represent one of the common causes of restoration replacement.[ 3 , 4 ] Cigarettes are considered the most commonly used form of tobacco. Tobacco stains are manifested as a black or dark brown discoloration covering the gingival third of teeth.[ 5 , 6 ] Although, cigarette smoke carries several toxic substances,[ 7 ] yet tar is the most important ingredient of tobacco that causes discoloration[ 8 ]. Thermal effects of cigarette smoke might be also another reason of discoloration[ 9 ]. Nowadays, recent nicotine products such as electronic cigarettes and heated tobacco products have become dramatically widespread. Yet, staining potential of such products and actual tobacco components causing discoloration is still unknown [ 10 ]. For direct restorations, resin composite restorative materials have been widely recommended due to their esthetic appeal. Despite mechanical and esthetic improvements, color instability remains the main concern of resin composites. Color stability of resin composites could be affected by the size of fillers, resin matrix type, polymerization depth and coloring agents.[ 11 ] On the other side, surface roughness of resin-based restorative materials has been shown to be also influenced by size, distribution, and quantity of filler particles, and composition of resin matrix.[ 12 ] It has been reported that small-sized filler particles exhibited better polishability, and hence lower color change.[ 13 ] Meanwhile, the method of finishing and polishing used has a great impact on the surface quality, as improper finishing and polishing can result in excessive plaque accumulation and increased surface staining and degradation.[ 14 ] Hence, the purpose of this study was to investigate the influence of smoking of conventional cigarettes and recent heated tobacco products along with different finishing and polishing protocols on color stability and surface roughness of resin composite restoration. The null hypothesis suggested was that neither smoking nor finishing and polishing protocol would affect color stability and surface roughness of resin composite. Materials and Methods 1. Materials: All products’ description, composition, manufacturer and lot number are presented in table 1. Table (1) Products’ description, composition, manufacturer and lot number. Products Description Composition Manufacturer Lot Number Palfique LX5 Supra nano-filled composite -Filler: 82% wt, 71% vol. Silica-zirconia filler and composite filler. Particle size range: 0.1 to 0.3µm. -Resin: Bis-GMA and Triethylene glycol dimethacrylate. Tokuyama Dental Corporation Inc., Japan 281E53 Diamond Master Discs Multi-step diamond finishing and polishing discs -Diamond sandpaper disks in coarse, medium, and fine grits. -Diamond Flex felt disks: micro bristles micronized diamond. FGM, Joinville, Santa Catarina, Brazil 4000000266 Diacomp Plus Twist Two-step polishing system Flexible plastic lamellae with embedded diamond grains of ≈ 20 µm. -Pre-polishing medium polisher (Pink): 40–50 µm. -High-shine fine polisher (Gray): 3–6 µm. EVE, Germany 486732 Diamond Excel polishing paste Diamond polishing paste Micronized diamond-based polishing paste with extra-fine grit (2–4 µm). FGM, Joinville, Santa Catarina, Brazil 4000002091 2. Methods: Samples size calculation: The sample size was calculated using G*Power 3.1.9.2 Software. For ∆E, sample size was estimated using data obtained from a previous study.[ 3 ] Based on a mean difference of 4.0 ± 0.8, the calculated effect size was 2.94 using a power of 95% for unpaired t-test and two-tailed significance level of 5%. The estimated sample size was 4 composite specimens per group, which was increased by 30% to 6 composite specimens in each group (N = 36 per 6 groups). For surface roughness, sample size was calculated based on a previous study [ 15 ] reporting a 0.335 ± 0.035 µm mean difference. Based on an effect size of 2.91 with a 5% significance level and a 95% test power, a minimum of 5 composite specimens were required per group, which was increased by 20% to 6 composite specimens per group (N = 36 per 6 groups). Study design: This research proposal was approved by the Research and Ethics Committee of the Faculty of Dentistry, The British University in Egypt, with approval no. 24–057. Seventy-two discs fabricated from a supra nanofilled composite were randomly divided to 6 groups (n = 12) according to study variables: 1. Tobacco Product (conventional cigarettes/CS; and heated tobacco product/HTP); and 2. Finishing/Polishing Protocol (control/C; multi-step finishing discs/FS; and Medium-grit abrasive bur + two-step polishing system). Half of the specimens of each study group (n = 6) was assigned for color stability assessment and the other half (n = 6) for surface roughness measurements. Specimens’ preparation: A diagrammatic illustration of specimens’ preparation procedures is presented in Fig. (1). Seventy-two composite discs (Palfique LX5, Tokuyama, Japan) of shade A2, 2 mm in thickness x 10 mm in diameter, were fabricated in a specially-designed split Teflon mold. A celluloid strip was fixed on a glass slab, over which the Teflon mold was placed. Composite was packed inside the mold and then another celluloid strip and glass slab were placed over the top surface of the composite with gentle finger pressure in order to allow excess material to escape and provide a smooth surface. Light polymerization was performed through the strip to prevent formation of oxygen inhibited layer for a total of 40 seconds, 20 seconds from top surface and 20 seconds from bottom surface, using a LED light-curing device (Elipar™ Deep Cure-L, 3M ESPE, USA) at a light intensity of 1200 mW/cm 2 . Light intensity of the curing device was regularly checked with a radiometer (Litex 682, Dentamerica Industry, USA). The cured specimens were stored in distilled water for 24 hours at 37°C. Finishing and polishing procedures: A diagrammatic illustration of specimen preparation procedures is presented in Fig. 1. The top surfaces of the composite discs were used as the experimental surfaces. To minimize variations, a single operator executed all finishing and polishing protocols with electric low speed contra-angled handpiece with transmission ratio 1:1 (T1 Line C 40 L, Dentsply Sirona, Germany). The specimens were held on split mold during finishing and polishing protocols. Pressure was maintained at 30–40 gm (≈ 0.3 newton) using a kitchen scale.[ 16 ] For standardization, each finishing and polishing step was performed in 10 strokes for 20 seconds in one direction in a planar motion, in order to permit comparison among them.[ 17 ] Group 1: Control group (C). Composite discs were cured against celluloid strip (TOR-VM, Russia) without finishing or polishing. Group 2: Multi-step finishing system (FS). Sandpaper discs in coarse, medium, and fine grits (Diamond Master, FGM, Brazil) were used in descending sequence, each for 20 seconds under dry condition. After each disc, specimens were rinsed with air-water spray for 10 seconds, then air-dried for 5 seconds. A diamond polishing paste (Diamond Excel, FGM, Brazil) was used with Diamond Flex felt disks as a final polishing step. Since there was no recommendation for rpm by the manufacturer, finishing was performed at 10000 rpm as the rpm of most finishing disc systems range from 10000 to 20000 RPM.[ 18 ] Each finishing disc was discarded after single use. Group 3: Two-step polishing system (PS). Prior to polishing, specimens were finished with super-fine diamond bur (Komet, Germany) with 25 µm particle grit size for 15 seconds under water coolant at 40000 rpm as per the manufacturer recommendation. Specimens were subsequently polished using medium (pink) and fine (grey) polishing wheels (DIACOMP PLUS TWIST, EVE, Germany) sequentially at 10,000 rpm for 20 seconds each with the conjunction of the diamond polishing paste with no water cooling [ 18 , 19 ]. After each step, specimens were rinsed with air-water spray for 10 seconds, then air-dried for 5 seconds. Each finishing burs and polishing wheel was discarded after 3 uses. Exposure to smoking: Conventional cigarettes, CS (LM, Philip Morris International Inc., Egypt) and heated tobacco products, HTP (Heets, Russet, Philip Morris International Inc., Italy) were used. Specimens were placed in a specially designed smoking apparatus[ 20 ] (Fig. 2) and exposed to 600 cigarettes/sticks, divided to 20 cigarettes each day, which represented 30 days of medium smoking behavior [ 21 ]. Afterwards, specimens were thoroughly rinsed with distilled water for 5 min in an ultrasonic cleaner (CD-4830, CODYSON, China) and dried with absorbent paper before color and surface roughness measurements. Color stability (ΔE): Color measurements were evaluated before and after smoking exposure. Specimens were on a standard white background before color measurement procedures. Color properties were measured using a digital spectrophotometer (VITA Easyshade Advance 4.01, VITA shade, VITA, USA). The tip of the device was placed over the center of the specimen. Color parameters were recorded as L*, a*, and b* values; where L is the axis of lightness, a is the axis of chromaticity (green-red), and b is the axis of color (blue-yellow). The color change (ΔE) was calculated using the following formula: ΔE2 − 1 = ([ΔL] 2 + [Δa] 2 + [Δb] 2 ) 1/2 . ΔE values are used to define color change in dental materials, and a ΔE value greater than 3.5 is considered clinically unacceptable.[ 22 ] Surface roughness: Surface roughness was evaluated before and after smoking exposure. Surface roughness (Ra) was recorded using a profilometer (JITAI8101 Surface Roughness Tester - Beijing Jitai Tech Detection Device Co., Ltd., China). Three measurements were taken from each surface at 3 equidistant points from the center, and the overall mean value was calculated for each specimen. The change in surface roughness was determined by calculating the difference between initial and final measurements for each specimen. Surface morphology evaluation under scanning electron microscopy (SEM): Surface morphology was evaluated using representative specimens from each group assigned for color change assessment before and after exposure to smoking. Specimens were vacuum-dried before examination. SEM examination was performed in Nanotechnology Research Center at The British University in Egypt using an environmental SEM (ThermoFisher, Quattro S Felid Emission Gun, Environmental SEM FEG ESEM, USA) in secondary electron mode at a standardized magnification x800. Statistical analysis: Statistical analysis was performed using IBM SPSS Statistics Software 25 for Windows (SPSS, Inc., Chicago, IL, USA). The significance level was set at p ≤ 0.05. Data were presented as mean and standard deviation (SD). Data normality was verified using Kolmogorov-Smirnov and Shapiro-Wilk test. Two-way ANOVA was used to investigate the effect of study variables on color stability and surface roughness. Intragroup comparisons were performed using One-Way ANOVA followed by post-hoc Tukey’s test. Intergroup comparisons were conducted using independent student t-test. Results Color stability (ΔE): One-Way ANOVA followed by post-hoc Tukey’s test (Table 2) dispkayed that there was a significant difference in ∆E values between finishing and polishing protocols within CS groups (P = 0.032). ∆E mean values of PS was significantly lower than control group. No significant difference was observed between control and PS groups, and between FS and PS groups. While within HTP groups, there was no significant difference between finishing/polishing protocols (P = 0.691). Independent student t-test (Table 2) showed that in all finishing/polishing protocols, CS displayed significantly higher ∆E mean values than HTP. Table (2): Mean ± St. Deviation for color change (∆E). Control FS PS P-value CS 11.93 ± 2.65 a 8.30 ± 2.37 ab 8.14 ± 2.52 b 0.032* HTP 2.31 ± 0.76 2.43 ± 1.24 2.94 ± 1.82 0.691 P-value 0.05). Mean values with different superscript letters within the same row are significantly different. Surface roughness: One-Way ANOVA followed by post-hoc Tukey’s test (Table 3) showed that there was a significant difference in roughness mean change between finishing/polishing protocols within CS groups (P = 0.026). Ra mean change of control was significantly higher than FS. No significant difference was detected between control and PS, and between FS and PS. While for HTP, there was no significant difference between finishing/polishing protocols (P = 0.734). Within control group, no significant difference in Ra values between CS and HTP. Whereas in FS and PS groups, Ra values of CS were significantly lower than HTP. Table (3): Mean ± St. Deviation for mean change in surface roughness Ra (µm). Control FS PS P-value CS 0.09 ± 0.18 a 0.02 ± 0.01 b 0.06 ± 0.07 ab 0.026* HTP 0.08 ± 0.05 0.10 ± 0.07 0.11 ± 0.08 0.734NS P-value 0.880NS 0.018* 0.012* *: significant ( p ≤ 0.05); NS: non-significant ( p > 0.05). Mean values with different superscript letters within the same row are significantly different. Surface morphology evaluation: The surface morphology micrographs of the studied specimens at 800X are presented in (Fig. 3). Prior to smoking exposure, control group showed a rougher surface compared to both finishing and polishing groups which produced a more homogenous surface with the formation of a resin smear layer along with the presence of some multidirectional scratches. After exposure to cigarette smoking, both finishing and polishing groups displayed smoother composite surfaces when compared to control group which showed an irregular surface topography. Deposition of organic materials on the surface was evident in all groups. After exposure to HTP smoking, control group showed comparable surface changes with both finishing and polishing groups. Discussion Color change of resin composite materials could be generally caused by the following reasons: (1) extrinsic factors such as plaque accumulation, smoking and dietary habits[ 23 ]; (2) surface alterations related to type of finishing/polishing system promoting surface degradation and adsorption of coloring agents[ 24 ]; and (3) intrinsic factors related to chemical composition and alterations in matrix/filler interphase of the material[ 23 , 25 ]. Since dental esthetics is of great concern nowadays, and since one of the crucial reasons for composite restoration replacement is staining and color change, the purpose of the present study was to assess color stability and surface roughness of a supra-nanofilled resin composite submitted to different smoking products (with 0.5 mg nicotine) and finishing/polishing protocols. In literature, there are few studies evaluating the effect of heated tobacco products on resin-based restorations[ 26 , 27 ]. In addition, not many studies have standardized the method of exposing restorative materials to cigarette smoke, such as the equipment design, number of cigarettes, smoke flow mechanism, smoke exposure time, simulation of oral cavity temperature and humidity[ 3 , 28 – 30 ]. In contrast to these studies, the design methodology of the current study was to use a specially designed apparatus with a suction power capacity of 500 mL volume similar to tidal volume per each respiratory cycle during smoking. The apparatus received one cigarette at a time permitting simultaneous unidirectional smoke inhalation and exhalation in a standardized time interval and speed. In order to simulate the oral cavity, temperature was set to 37°C at 100% humidity by the aid of a thermal regulator. Regarding color stability findings, a significant change in color (∆E = 8.14–11.93) was found in resin composite specimens exposed to conventional cigarettes, regardless of the finishing and polishing system, which was visually perceptible and considered clinically unacceptable.[ 22 ] On the contrary, all specimens exposed to heated tobacco products displayed a minor color change (∆E = 2.31–2.94), which was considered clinically acceptable.[ 22 ] Thus, the null hypothesis that smoking would have no effect on color stability of resin composite was partially rejected. Cigarette smoke is made up of a mixture of particulate and volatile components.[ 7 ] The particulate phase mainly consists of tar, while the volatile phase includes carbon monoxide, carbon dioxide, nitrogen monoxide and water. Tar represents more that 90% of smoke products. The tar precipitates on cigarette filters turning their color into yellow-brown, could be more likely the main agent causing discoloration of teeth and restorations.[ 4 , 28 ] Upon combustion of those elements, dark pigments and metals like cadmium, arsenic, nickel and lead are released.[ 31 ] Deposits of these elements may have adhered to top surfaces of composite specimens, resulting in staining and surface alterations.[ 32 ] More darkening and yellowing of the specimens were observed for conventional cigarettes group compared to HTP group, interpreted by the significant reduction in L∗ coordinate and increase in a∗ and b∗ coordinates. This agrees with a previous study showing a prominent discoloration effect of conventional cigarette smoke on artificial denture teeth in comparison to HTP smoke. The reduced staining potential of HTP could be attributed to the higher aerosols generated from heated sticks when compared to cigarette smoke.[ 33 ] HTP device used in the current study consisted of a tobacco heating system different from the burning process that occurs with a lighted cigarette, thus producing less harmful ingredients. The combustion of conventional cigarettes may reach a temperature higher than 600°C,[ 34 ] whereas HTP can be heated up to 350°C.[ 35 ] When heated instead of burning, aerosols of suspended liquid droplets are liberated, thus eliminating the formation of any carbon-based solid particulates.[ 36 ] These aerosols showed a different chemical composition, composed primarily of water, nicotine and glycerin.[ 37 ] Nicotine is colorless in its original form, however, its oxidized state can cause yellowish staining.[ 1 ] This might explain the reduced discoloration effect on specimens exposed to HTP smoke in comparison to conventional cigarette smoke, irrespective of the finishing/polishing protocol. Within conventional cigarettes groups, control specimens showed higher color change compared to both finishing and polishing groups. Meanwhile, there was no significant difference in ∆E values between control and finishing and polishing groups in heated tobacco products groups. Hence, the null hypothesis that finishing and polishing protocol would not affect color stability of resin composite was partially accepted. The fact that control specimens cured against polyester strip presented more staining than those submitted to either finishing and polishing protocol may be justified by the superior homogeneity of the composite surface resulting after finishing and polishing, rendering the surface more regular.[ 38 , 39 ] As proved in a previous study,[ 40 ] smoother composite surfaces produced from the adaptation of polyester strip are not necessarily more resistant to discoloration. In contrast, photo-polymerization of control specimens under pressure of polyester strip, may have created a superficial layer rich in organic matrix with lower filler loading.[ 41 ] Thus, this unpolished surface became unstable and have readily adsorbed the pigments emitted from the combustion products of cigarettes smoke. These findings came in accordance with those of a previous study which demonstrated an increased potential of cigarette smoke to stain all composite samples in the absence of polishing, along with increased surface roughness.[ 31 ] Regarding surface roughness, both smoking groups showed statistically similar mean change in Ra in control specimens. Whereas, specimens exposed to heated tobacco products showed significantly higher Ra mean change compared to conventional cigarettes in both finishing and polishing groups. Therefore, the null hypothesis that smoking would not affect composite surface roughness was partially rejected. As previously mentioned, the absence of finishing and polishing renders the composite surface more irregular and rougher owing to uneven matrix-filler distribution.[ 38 , 39 ] Since heated tobacco system heats tobacco without burning/combustion to release nicotine-containing aerosols, the composition of the aerosol is greatly different form the smoke liberated by combustible products of conventional cigarettes.[ 33 , 34 ] IQOS aerosol primarily contains water which comprises more than 80%.[ 35 ] Due to this high water content, aerosols formed from the condensation of water vapor caused wetting of composite surfaces. The hydrophilic character of TEGDMA monomer present in the composition of the tested resin composite is expected to increase water sorption.[ 42 ] The presence of Bis-GMA monomer which can also hydrogen bond to adsorbed water through its OH-groups.[ 42 ] Water acts as a polymer plasticizer, leading to hydrolytic degradation and surface deterioration of resin composite. Hence, adsorbed water could have weakened intermolecular bonds of resin matrix causing swelling of polymer network; minimizing frictional forces between polymer chains.[ 43 ] Moreover, a number of organic acids were identified in the total particulate matter of IQOS mainstream. The acidic pH of IQOS smoke originating from the combination of nicotine salts with organic acids,[ 44 ] resulting in protonation and release of H + ions which may have broken C-C bonds of polymer matrix as well as siloxane bonds connecting matrix to fillers; thereby releasing filler particles leading to exposure of resin matrix.[ 45 ] Besides thermal effects of emitted aerosols, this could have assumably contributed to increasing surface roughness values of all specimens in HTP groups.[ 3 ] As for the conventional cigarettes groups, mean change in Ra values in control group was higher than two-step polishing system, followed by multi-step finishing system. On the contrary, no significant difference in Ra mean change between control and finishing and polishing groups when exposed to heated tobacco products. Hence, the null hypothesis that finishing and polishing protocol would have no influence on surface roughness was partially rejected. Our findings were in agreement with the study of Itanto et al.,[ 46 ] who reported an improved surface finish of a nanofilled composite resin after using a multi-step finishing system. This could be attributed to the flexibility, composition and technique of usage of the aluminum oxide discs.[ 47 ] The malleability of such discs promotes better adaptation and homogenous abrasion of both filler particles and resin matrix, preventing filler displacement from the matrix.[ 47 ] This system is also structured to be used in a sequential order of descending abrasiveness level, starting with coarse, medium, fine grains, and finalizing with felt discs in a unidirectional planar movement; hence favoring a final smoother surface texture. In the two-step polishing protocol, a pre-roughening step with diamond burs was performed, to simulate the clinical situation. The fine-grit yellow-coded abrasive burs equivalent to the coarse aluminium discs of the multi-step system were selected, in order to minimize scattering of the initial roughness values between both groups. This finishing step was followed by pre-polishing with medium-grain spiral, then final polishing with fine-grain spiral. Discoid shape polishers were used in the current study aiming to exclude the effect of tool geometry on surface roughness results.[ 48 ] Moreover, the specimens fabricated in this study were flat discs, which might be relatively easier for the wheel-shaped polishing tips to come in direct contact with the flat surface of the specimens, producing a high shine finish.[ 39 ] It was also concluded in a former study that diamond particles impregnated within the flexible rubber material of the polishers have higher toughness and hardness than aluminium oxide and silicone carbide particles, which may have attributed to more homogenous abrasion and effective polishing.[ 49 , 50 ] These results came in accordance with those of Di Silva et al.,[ 15 ] who claimed that EVE Diacomp Twist Plus was effective in reducing surface roughness. However, theses findings did not follow those of Elgammal et al.,[ 51 ] who reported high surface roughness results with the two-step polishing system. This disparity could be related to the difference in the type of composite material tested, as they were using a bulk fill resin composite. To ensure standardization of finishing and polishing procedures, all steps were executed by the same operator following respective manufacturers’ recommendations regarding speed and motion. Moreover, the applied pressure during polishing procedures was controlled at light pressure of approximately 30–40 grams using a precision scale. A diamond polishing paste was used with final polishing step of both systems as several studies[ 52 ] proved its efficacy in providing a smoother and glossier surface finish. This is largely due to the great wear capacity of the diamond paste as diamond particles are harder than composite filler particles.[ 52 , 53 ] Consequently, this would enable equal and uniform removal of both composite phases, hence, minimizing surface roughness. This was supported by SEM photomicropraphs of conventional cigarettes group, which illustrated smoother surfaces of specimens subjected to both finishing and polishing systems when compared to control group. It seems that F/P systems created a resin smear layer on the composite surfaces with some multidirectional scratches. In the present study, all surface roughness values, irrespective to smoking or finishing and polishing protocol, were lower than 0.2 µm, which is the critical size for bacterial adhesion. These values were in accordance with the surface quality standard ISO 1302:2002.[ 54 ] Limitations of the present study include lack of assessment of different brands and flavors, varying nicotine concentrations, and tooth brushing simulation during smoke exposure. Future studies are also recommended to investigate the effect of other commercially available finishing and polishing systems and polishing pastes with different particle sizes on color stability and surface topography of resin composite materials. Conclusion Under the limitations of the current study, it could be withdrawn that: Conventional cigarette smoking resulted in a pronounced color change in composite compared to heated tobacco product. Smoking of heated tobacco product produced an increased surface roughness compared to conventional cigarettes. Both multi-step finishing system and two-step polishing system showed comparable color change and surface roughness in composite. Declarations Funding: Open access funding provided by The Science, Technology & Innovation Funding Authority (STDF) in cooperation with The Egyptian Knowledge Bank (EKB). Competing interests : Authors confirm that they have no conflict of interest. Ethical approval and consent to participate : The research proposal was reviewed and approved by the Research and Ethics Committee of the Faculty of Dentistry, The British University in Egypt, with approval no. 24–057. Consent for publication : Not applicable for this study. Data availability : The data supporting the findings of the present study are available within the article. Authors contribution : M.A. designed the smoking device and prepared the study design. M.S.S. conducted the practical work and specimens’ preparation. M.S.S. & S.A.B. carried out measurements. S.A.B. conducted data collection and statistical analysis. S.A.B. & M.S.S. wrote the manuscript. M.S. & F.M. reviewed and proofread the manuscript. 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Mathias P, Rossi TA, Cavalcanti AN, Lima MJ, Fontes CM, Nogueira-Filho Gda R. Cigarette smoke combined with staining beverages decreases luminosity and increases pigmentation in composite resin restorations. Compendium Continuing Educ Dentistry. 2011;32(2):66–70. Wasilewski Mde S, Takahashi MK, Kirsten GA, de Souza EM. Effect of cigarette smoke and whiskey on the color stability of dental composites. Am J Dent. 2010;23(1):4–8. Baboni FB, Guariza Filho O, Moreno AN, Rosa EA. Influence of cigarette smoke condensate on cariogenic and candidal biofilm formation on orthodontic materials. Am J Orthod Dentofac Orthop. 2010;138(4):427–34. McCann D. Tobacco use and oral health. J Am Dent Association. 1989;118(1):18–25. Ayaz EA, Altintas SH, Turgut S. Effects of cigarette smoke and denture cleaners on the surface roughness and color stability of different denture teeth. J Prosthet Dent. 2014;112(2):241–8. Kurachi T, Chuman S, Suzuki T, Kubota T, Ishikawa S. Effects of Aerosols From Heated Tobacco Products With Flavors on the Discoloration of Bovine Tooth Enamel. Clin Experimental Dent Res. 2023;9(6):1069–77. WHO Heated Tobacco Products Information Sheet. (accessed on 20. February 2023). Philip Morris SA. IQOS explained, PMI website, undated, accessed December 2019. Bekki K, Inaba Y, Uchiyama S, Kunugita N. Comparison of Chemicals in Mainstream Smoke in Heat-not-burn Tobacco and Combustion Cigarettes. J UOEH. 2017;39(3):201–7. Pratte P, Cosandey S, Goujon Ginglinger C. Investigation of solid particles in the mainstream aerosol of the Tobacco Heating System THS2.2 and mainstream smoke of a 3R4F reference cigarette. Hum Exp Toxicol. 2017;36(11):1115–20. Dhananjaya KM, Vadavadagi SV, Almalki SA, Verma T, Arora S, Kumar NN. In Vitro Analysis of Different Polishing Systems on the Color Stability and Surface Roughness of Nanocomposite Resins. J Contemp Dent Pract. 2019;20(11):1335–8. Abo-Eldahab G, Kamel M, Nour K. The Effect of Different Polishing Methods on the Surface Roughness of Resin Composites (An In-Vitro Study). Egypt Dent J. 2022;68(4):4039–51. Patel SB, Gordan VV, Barrett AA, Shen C. The effect of surface finishing and storage solutions on the color stability of resin-based composites. J Am Dent Assoc. 2004;135(5):587–94. quiz 654. Shintani H, Satou J, Satou N, Hayashihara H, Inoue T. Effects of various finishing methods on staining and accumulation of Streptococcus mutans HS-6 on composite resins. Dent Mater. 1985;1(6):225–7. Feilzer YJ, Feilzer AJ, Noack MJ, Kleverlaan CJ. Release of contraction stress of dental resin composites by water sorption. Dent Mater. 2024;40(10):1697–701. Yiu CK, King NM, Pashley DH, Suh BI, Carvalho RM, Carrilho MR, Tay FR. Effect of resin hydrophilicity and water storage on resin strength. Biomaterials. 2004;25(26):5789–96. Harvanko AM, Havel CM, Jacob P, Benowitz NL. Characterization of nicotine salts in 23 electronic cigarette refill liquids. Nicotine Tob Res. 2020;22(7):1239–43. Chandra J, Setyowati L, Setyabudi. Surface roughness of nanofilled and ubah composite resins exposed to kretek cigarette smoke. Conservative Dentistry J. 2019;8(1):30–5. Itanto BS, Usman M, Margono A. Comparison of surface roughness of nanofilled and nanohybrid composite resins after polishing with a multi-step technique. Journal of Physics: Conference Series. 2017;884(1):012091. Yap AU, Ng JJ, Yap SH, et al. Surface finish of resin-modified and highly viscous glass ionomer cements produced by new one-step systems. Operative Dentistry-University Wash. 2004;29(1):87–91. Jefferies SR. Abrasive Finishing and Polishing in Restorative Dentistry: A State-of-the-Art Review. Dental Clin N Am. 2007;51(2):379–97. Albers HF. Placement and finishing. Tooth-colored restoratives: Principles and Techniques. 9th ed. London: BC Decker Inc.,Hamilton; 2002. pp. 162–81. Farzaneh F, Mohammadi-Bassir M, Rezvani MB, Dehestani Ardakani F. Effect of Chemical and Mechanical Degradation on Surface Roughness, Topography, Gloss, and Polish Retention of Three Composites Polished with Five Polishing Systems. Front Dentistry. 2021;18:39. Elgammal YA, Temirek MM, Hassanein OE, Abdelaziz MM. The Effect of Different Finishing and Polishing Systems on Surface Properties of New Flowable Bulk-fill Resin Composite. J Contemp Dent Pract. 2023;24(8):587–94. Lainović T, Blažić L, Kukuruzović D, Vilotić M, Ivanišević A, Kakaš D. Effect of Diamond Paste Finishing on Surface Topography and Roughness of Dental Nanohybrid Composites – AFM Analysis. Procedia Eng. 2014;69:945–51. Kurt A, Cilingir A, Bilmenoglu C, Topcuoglu N, Kulekci G. Effect of different polishing techniques for composite resin materials on surface properties and bacterial biofilm formation. J Dent. 2019;90:103199. Busscher HJ, Rinastiti M, Siswomihardjo W, Vander Mei HC. Biofilm formation on dental restorative and implant materials. J Dent Res. 2010;89(7):657–65. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 05 Dec, 2025 Read the published version in BMC Oral Health → Version 1 posted Editorial decision: Revision requested 02 May, 2025 Reviews received at journal 01 May, 2025 Reviewers agreed at journal 23 Apr, 2025 Reviews received at journal 17 Apr, 2025 Reviews received at journal 06 Apr, 2025 Reviewers agreed at journal 06 Apr, 2025 Reviewers agreed at journal 05 Apr, 2025 Reviewers invited by journal 03 Apr, 2025 Editor assigned by journal 19 Mar, 2025 Editor invited by journal 19 Mar, 2025 Submission checks completed at journal 18 Mar, 2025 First submitted to journal 18 Mar, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6163357","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":437839284,"identity":"f4cc0d62-ee9c-4bf6-8d90-6dc3c394cdf0","order_by":0,"name":"Mohamed Samy Salama","email":"","orcid":"","institution":"The British University in Egypt","correspondingAuthor":false,"prefix":"","firstName":"Mohamed","middleName":"Samy","lastName":"Salama","suffix":""},{"id":437839285,"identity":"923eb768-a6e2-4674-9188-06e5b92a168f","order_by":1,"name":"Sara Adel Botros","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+UlEQVRIiWNgGAWjYJACZgaGAxDWxwYwZUCcFh4gg3EmyVqYeYnRIt9+9uHnAoY7cvbShw9/tt1xWI6BvXmbBENFLU4tBmfSjaVnMDwz5uFLS5POPXPYmIHnWJkEw5njuLUwpDFI8zAcTuzh4TFjzm07nNggkWMmwdh2DLfD+p8x/4ZqMf5s2Xa4vkH+DVDLP9xaGG6kscFsMZBmbDucwCDBA9TSUIPbYTeesVnzGAD9coYtTbL3TLphG09asUXCsQN4HJbGfJun4o4cew/z4Q8/d1jL87Mf3njjQ00dbodBAwEB2EBEAsNhAlqwAEK2jIJRMApGwQgCAG6GTLHElUvkAAAAAElFTkSuQmCC","orcid":"","institution":"The British University in Egypt","correspondingAuthor":true,"prefix":"","firstName":"Sara","middleName":"Adel","lastName":"Botros","suffix":""},{"id":437839287,"identity":"afe45bb8-e261-495c-ac27-8966232437fb","order_by":2,"name":"Fatma Makkeyah","email":"","orcid":"","institution":"The British University in Egypt","correspondingAuthor":false,"prefix":"","firstName":"Fatma","middleName":"","lastName":"Makkeyah","suffix":""},{"id":437839292,"identity":"b03a52a4-c2fb-4378-aec0-6757b94d7b09","order_by":3,"name":"Mohamed Shamel","email":"","orcid":"","institution":"The British University in Egypt","correspondingAuthor":false,"prefix":"","firstName":"Mohamed","middleName":"","lastName":"Shamel","suffix":""},{"id":437839293,"identity":"3992c36f-edd7-49ed-800e-5ac32a8c0fcf","order_by":4,"name":"Mahmoud Al Ankily","email":"","orcid":"","institution":"The British University in Egypt","correspondingAuthor":false,"prefix":"","firstName":"Mahmoud","middleName":"Al","lastName":"Ankily","suffix":""}],"badges":[],"createdAt":"2025-03-05 14:08:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6163357/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6163357/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12903-025-07161-1","type":"published","date":"2025-12-05T15:58:16+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":79894640,"identity":"7ba2bcab-42b8-48f3-944f-a9982b053b8b","added_by":"auto","created_at":"2025-04-04 08:46:00","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":157663,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDiagrammatic illustration of specimen preparation procedures.\u003c/strong\u003e Specimen preparation steps of (a) Control group, (b) Multi-step finishing system group (Diamond Master), and (c) Two-step polishing system group (Diacomp Plus Twist). Specimen exposure to (d) conventional cigarettes smoking (LM Blue) and (e) heated tobacco products (Heets Russet). Analysis of (f) color stability, (g) surface roughness and (h) surface morphology under SEM before and after smoking.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6163357/v1/a893345bb4c7dbd727a2c329.png"},{"id":79894641,"identity":"2039ee0c-4a2e-48ae-bc19-8d5707593e36","added_by":"auto","created_at":"2025-04-04 08:46:00","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":89430,"visible":true,"origin":"","legend":"\u003cp\u003eThe smoking apparatus consists of (A) a gearbox to slow down the motor speed to 2 Hz (2 cycles/sec) with a crankshaft attached to a slider to change the movement to linear instead of rotation of 4.5 cm distance. (B) A stainless steel hollow chamber of 12 cm internal diameter with a piston to produce a suction power of 500 ml volume that simulates tidal volume taking during smoking. The cigarettes or electronic smoking device were attached to (C) an inhalation valve allowing unidirectional smoke inflow. (D) An exhalation valve which allows unidirectional smoke outflow. (E) A water container with a heater placed at the bottom of the device, which was connected to (F) a thermal sensor to adjust temperature at 37°C and 100% humidity similar to oral cavity. Specimens were placed on (G) perforated trays to allow penetration of smoke.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6163357/v1/165f102eb1d3f66da244277a.png"},{"id":79894642,"identity":"55651284-68a8-4dd5-82fa-316ca72e39ed","added_by":"auto","created_at":"2025-04-04 08:46:00","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":227576,"visible":true,"origin":"","legend":"\u003cp\u003eSEM photomicrographs of composite top surfaces at magnification X800.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6163357/v1/9ea29d64ae23939ea348e21f.png"},{"id":97723954,"identity":"73e719ea-14c4-41bc-8954-5136527905a2","added_by":"auto","created_at":"2025-12-08 16:10:09","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1351007,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6163357/v1/53060b9f-da02-4d7e-8497-7ba64a36ef8c.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Effect of Smoking and Finishing and Polishing Protocol on Color Stability and Surface Roughness of Resin Composite","fulltext":[{"header":"Introduction","content":"\u003cp\u003eTooth discoloration is one of the chief esthetic concerns as it influences the physical and social appeal of the patient. Particularly, smokers\u0026rsquo; teeth tend to develop tobacco stains resulting in tooth discoloration and restoration staining.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] Tooth discoloration is classified as intrinsic or extrinsic discoloration, where extrinsic staining are caused by external factors that adhere to the tooth surface, like tobacco stains.[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] The color change of restorations following smoking represent one of the common causes of restoration replacement.[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eCigarettes are considered the most commonly used form of tobacco. Tobacco stains are manifested as a black or dark brown discoloration covering the gingival third of teeth.[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] Although, cigarette smoke carries several toxic substances,[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] yet tar is the most important ingredient of tobacco that causes discoloration[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Thermal effects of cigarette smoke might be also another reason of discoloration[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Nowadays, recent nicotine products such as electronic cigarettes and heated tobacco products have become dramatically widespread. Yet, staining potential of such products and actual tobacco components causing discoloration is still unknown [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFor direct restorations, resin composite restorative materials have been widely recommended due to their esthetic appeal. Despite mechanical and esthetic improvements, color instability remains the main concern of resin composites. Color stability of resin composites could be affected by the size of fillers, resin matrix type, polymerization depth and coloring agents.[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eOn the other side, surface roughness of resin-based restorative materials has been shown to be also influenced by size, distribution, and quantity of filler particles, and composition of resin matrix.[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] It has been reported that small-sized filler particles exhibited better polishability, and hence lower color change.[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] Meanwhile, the method of finishing and polishing used has a great impact on the surface quality, as improper finishing and polishing can result in excessive plaque accumulation and increased surface staining and degradation.[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eHence, the purpose of this study was to investigate the influence of smoking of conventional cigarettes and recent heated tobacco products along with different finishing and polishing protocols on color stability and surface roughness of resin composite restoration. The null hypothesis suggested was that neither smoking nor finishing and polishing protocol would affect color stability and surface roughness of resin composite.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e1. Materials:\u003c/h2\u003e \u003cp\u003eAll products\u0026rsquo; description, composition, manufacturer and lot number are presented in table 1.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eTable\u0026nbsp;(1)\u003c/strong\u003e \u003cp\u003eProducts\u0026rsquo; description, composition, manufacturer and lot number.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProducts\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDescription\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eComposition\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eManufacturer\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLot Number\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePalfique LX5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSupra nano-filled composite\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-Filler: 82% wt, 71% vol. Silica-zirconia filler and composite filler. Particle size range: 0.1 to 0.3\u0026micro;m.\u003c/p\u003e \u003cp\u003e-Resin: Bis-GMA and Triethylene glycol dimethacrylate.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTokuyama Dental\u003c/p\u003e \u003cp\u003eCorporation Inc., Japan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e281E53\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiamond Master Discs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMulti-step diamond finishing and polishing discs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-Diamond sandpaper disks in coarse, medium, and fine grits.\u003c/p\u003e \u003cp\u003e-Diamond Flex felt disks: micro bristles micronized diamond.\u003c/p\u003e\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFGM, Joinville, Santa Catarina, Brazil\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4000000266\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiacomp Plus Twist\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTwo-step polishing system\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFlexible plastic lamellae with embedded diamond grains of \u0026asymp;\u0026thinsp;20 \u0026micro;m.\u003c/p\u003e \u003cp\u003e-Pre-polishing medium polisher (Pink): 40\u0026ndash;50 \u0026micro;m.\u003c/p\u003e \u003cp\u003e-High-shine fine polisher (Gray): 3\u0026ndash;6 \u0026micro;m.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eEVE, Germany\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e486732\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiamond Excel polishing paste\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDiamond polishing paste\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMicronized diamond-based polishing paste with extra-fine grit (2\u0026ndash;4 \u0026micro;m).\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFGM, Joinville, Santa Catarina, Brazil\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4000002091\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003e2. Methods:\u003c/h3\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eSamples size calculation:\u003c/h2\u003e \u003cp\u003eThe sample size was calculated using G*Power 3.1.9.2 Software. For ∆E, sample size was estimated using data obtained from a previous study.[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] Based on a mean difference of 4.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8, the calculated effect size was 2.94 using a power of 95% for unpaired t-test and two-tailed significance level of 5%. The estimated sample size was 4 composite specimens per group, which was increased by 30% to 6 composite specimens in each group (N\u0026thinsp;=\u0026thinsp;36 per 6 groups). For surface roughness, sample size was calculated based on a previous study [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] reporting a 0.335\u0026thinsp;\u0026plusmn;\u0026thinsp;0.035 \u0026micro;m mean difference. Based on an effect size of 2.91 with a 5% significance level and a 95% test power, a minimum of 5 composite specimens were required per group, which was increased by 20% to 6 composite specimens per group (N\u0026thinsp;=\u0026thinsp;36 per 6 groups).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eStudy design:\u003c/h3\u003e\n\u003cp\u003e This research proposal was approved by the Research and Ethics Committee of the Faculty of Dentistry, The British University in Egypt, with approval no. 24\u0026ndash;057. Seventy-two discs fabricated from a supra nanofilled composite were randomly divided to 6 groups (n\u0026thinsp;=\u0026thinsp;12) according to study variables: 1. Tobacco Product (conventional cigarettes/CS; and heated tobacco product/HTP); and 2. Finishing/Polishing Protocol (control/C; multi-step finishing discs/FS; and Medium-grit abrasive bur\u0026thinsp;+\u0026thinsp;two-step polishing system). Half of the specimens of each study group (n\u0026thinsp;=\u0026thinsp;6) was assigned for color stability assessment and the other half (n\u0026thinsp;=\u0026thinsp;6) for surface roughness measurements.\u003c/p\u003e\n\u003ch3\u003eSpecimens’ preparation:\u003c/h3\u003e\n\u003cp\u003eA diagrammatic illustration of specimens\u0026rsquo; preparation procedures is presented in Fig.\u0026nbsp;(1). Seventy-two composite discs (Palfique LX5, Tokuyama, Japan) of shade A2, 2 mm in thickness x 10 mm in diameter, were fabricated in a specially-designed split Teflon mold. A celluloid strip was fixed on a glass slab, over which the Teflon mold was placed. Composite was packed inside the mold and then another celluloid strip and glass slab were placed over the top surface of the composite with gentle finger pressure in order to allow excess material to escape and provide a smooth surface. Light polymerization was performed through the strip to prevent formation of oxygen inhibited layer for a total of 40 seconds, 20 seconds from top surface and 20 seconds from bottom surface, using a LED light-curing device (Elipar\u0026trade; Deep Cure-L, 3M ESPE, USA) at a light intensity of 1200 mW/cm\u003csup\u003e2\u003c/sup\u003e. Light intensity of the curing device was regularly checked with a radiometer (Litex 682, Dentamerica Industry, USA). The cured specimens were stored in distilled water for 24 hours at 37\u0026deg;C.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eFinishing and polishing procedures:\u003c/h2\u003e \u003cp\u003eA diagrammatic illustration of specimen preparation procedures is presented in Fig.\u0026nbsp;1. The top surfaces of the composite discs were used as the experimental surfaces. To minimize variations, a single operator executed all finishing and polishing protocols with electric low speed contra-angled handpiece with transmission ratio 1:1 (T1 Line C 40 L, Dentsply Sirona, Germany). The specimens were held on split mold during finishing and polishing protocols. Pressure was maintained at 30\u0026ndash;40 gm (\u0026asymp;\u0026thinsp;0.3 newton) using a kitchen scale.[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] For standardization, each finishing and polishing step was performed in 10 strokes for 20 seconds in one direction in a planar motion, in order to permit comparison among them.[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/p\u003e \u003cp\u003e \u003cb\u003eGroup 1: Control group (C).\u003c/b\u003e \u003c/p\u003e \u003cp\u003eComposite discs were cured against celluloid strip (TOR-VM, Russia) without finishing or polishing.\u003c/p\u003e \u003cp\u003e \u003cb\u003eGroup 2: Multi-step finishing system (FS).\u003c/b\u003e \u003c/p\u003e \u003cp\u003eSandpaper discs in coarse, medium, and fine grits (Diamond Master, FGM, Brazil) were used in descending sequence, each for 20 seconds under dry condition. After each disc, specimens were rinsed with air-water spray for 10 seconds, then air-dried for 5 seconds. A diamond polishing paste (Diamond Excel, FGM, Brazil) was used with Diamond Flex felt disks as a final polishing step. Since there was no recommendation for rpm by the manufacturer, finishing was performed at 10000 rpm as the rpm of most finishing disc systems range from 10000 to 20000 RPM.[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] Each finishing disc was discarded after single use.\u003c/p\u003e \u003cp\u003e \u003cb\u003eGroup 3: Two-step polishing system (PS).\u003c/b\u003e \u003c/p\u003e \u003cp\u003ePrior to polishing, specimens were finished with super-fine diamond bur (Komet, Germany) with 25 \u0026micro;m particle grit size for 15 seconds under water coolant at 40000 rpm as per the manufacturer recommendation. Specimens were subsequently polished using medium (pink) and fine (grey) polishing wheels (DIACOMP PLUS TWIST, EVE, Germany) sequentially at 10,000 rpm for 20 seconds each with the conjunction of the diamond polishing paste with no water cooling [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. After each step, specimens were rinsed with air-water spray for 10 seconds, then air-dried for 5 seconds. Each finishing burs and polishing wheel was discarded after 3 uses.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eExposure to smoking:\u003c/h3\u003e\n\u003cp\u003eConventional cigarettes, CS (LM, Philip Morris International Inc., Egypt) and heated tobacco products, HTP (Heets, Russet, Philip Morris International Inc., Italy) were used. Specimens were placed in a specially designed smoking apparatus[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] (Fig.\u0026nbsp;2) and exposed to 600 cigarettes/sticks, divided to 20 cigarettes each day, which represented 30 days of medium smoking behavior [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Afterwards, specimens were thoroughly rinsed with distilled water for 5 min in an ultrasonic cleaner (CD-4830, CODYSON, China) and dried with absorbent paper before color and surface roughness measurements.\u003c/p\u003e\n\u003ch3\u003eColor stability (ΔE):\u003c/h3\u003e\n\u003cp\u003eColor measurements were evaluated before and after smoking exposure. Specimens were on a standard white background before color measurement procedures. Color properties were measured using a digital spectrophotometer (VITA Easyshade Advance 4.01, VITA shade, VITA, USA). The tip of the device was placed over the center of the specimen. Color parameters were recorded as L*, a*, and b* values; where L is the axis of lightness, a is the axis of chromaticity (green-red), and b is the axis of color (blue-yellow). The color change (ΔE) was calculated using the following formula: ΔE2\u0026thinsp;\u0026minus;\u0026thinsp;1 = ([ΔL]\u003csup\u003e2\u003c/sup\u003e + [Δa]\u003csup\u003e2\u003c/sup\u003e + [Δb]\u003csup\u003e2\u003c/sup\u003e)\u003csup\u003e1/2\u003c/sup\u003e. ΔE values are used to define color change in dental materials, and a ΔE value greater than 3.5 is considered clinically unacceptable.[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eSurface roughness:\u003c/h2\u003e \u003cp\u003eSurface roughness was evaluated before and after smoking exposure. Surface roughness (Ra) was recorded using a profilometer (JITAI8101 Surface Roughness Tester - Beijing Jitai Tech Detection Device Co., Ltd., China). Three measurements were taken from each surface at 3 equidistant points from the center, and the overall mean value was calculated for each specimen. The change in surface roughness was determined by calculating the difference between initial and final measurements for each specimen.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eSurface morphology evaluation under scanning electron microscopy (SEM):\u003c/h2\u003e \u003cp\u003eSurface morphology was evaluated using representative specimens from each group assigned for color change assessment before and after exposure to smoking. Specimens were vacuum-dried before examination. SEM examination was performed in Nanotechnology Research Center at The British University in Egypt using an environmental SEM (ThermoFisher, Quattro S Felid Emission Gun, Environmental SEM FEG ESEM, USA) in secondary electron mode at a standardized magnification x800.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis:\u003c/h2\u003e \u003cp\u003eStatistical analysis was performed using IBM SPSS Statistics Software 25 for Windows (SPSS, Inc., Chicago, IL, USA). The significance level was set at p\u0026thinsp;\u0026le;\u0026thinsp;0.05. Data were presented as mean and standard deviation (SD). Data normality was verified using Kolmogorov-Smirnov and Shapiro-Wilk test. Two-way ANOVA was used to investigate the effect of study variables on color stability and surface roughness. Intragroup comparisons were performed using One-Way ANOVA followed by post-hoc Tukey\u0026rsquo;s test. Intergroup comparisons were conducted using independent student t-test.\u003c/p\u003e "},{"header":"Results","content":"\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eColor stability (ΔE):\u003c/h2\u003e \u003cp\u003eOne-Way ANOVA followed by post-hoc Tukey\u0026rsquo;s test (Table\u0026nbsp;2) dispkayed that there was a significant difference in ∆E values between finishing and polishing protocols within CS groups (P\u0026thinsp;=\u0026thinsp;0.032). ∆E mean values of PS was significantly lower than control group. No significant difference was observed between control and PS groups, and between FS and PS groups. While within HTP groups, there was no significant difference between finishing/polishing protocols (P\u0026thinsp;=\u0026thinsp;0.691). Independent student t-test (Table\u0026nbsp;2) showed that in all finishing/polishing protocols, CS displayed significantly higher ∆E mean values than HTP.\u003c/p\u003e \u003cp\u003e \u003cb\u003eTable\u0026nbsp;(2): Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;St. Deviation for color change (∆E).\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabb\" border=\"1\"\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eControl\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFS\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePS\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eP-value\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCS\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.93\u0026thinsp;\u0026plusmn;\u0026thinsp;2.65\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.30\u0026thinsp;\u0026plusmn;\u0026thinsp;2.37\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.14\u0026thinsp;\u0026plusmn;\u0026thinsp;2.52\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.032*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHTP\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.31\u0026thinsp;\u0026plusmn;\u0026thinsp;0.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.43\u0026thinsp;\u0026plusmn;\u0026thinsp;1.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.94\u0026thinsp;\u0026plusmn;\u0026thinsp;1.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.691\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eP-value\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.001*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.003*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e*: significant (\u003cem\u003ep\u0026thinsp;\u0026le;\u003c/em\u003e\u0026thinsp;0.05); NS: non-significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eMean values with different superscript letters within the same row are significantly different.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eSurface roughness:\u003c/h2\u003e \u003cp\u003eOne-Way ANOVA followed by post-hoc Tukey\u0026rsquo;s test (Table\u0026nbsp;3) showed that there was a significant difference in roughness mean change between finishing/polishing protocols within CS groups (P\u0026thinsp;=\u0026thinsp;0.026). Ra mean change of control was significantly higher than FS. No significant difference was detected between control and PS, and between FS and PS. While for HTP, there was no significant difference between finishing/polishing protocols (P\u0026thinsp;=\u0026thinsp;0.734). Within control group, no significant difference in Ra values between CS and HTP. Whereas in FS and PS groups, Ra values of CS were significantly lower than HTP.\u003c/p\u003e \u003cp\u003e \u003cb\u003eTable\u0026nbsp;(3): Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;St. Deviation for mean change in surface roughness Ra (\u0026micro;m).\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabc\" border=\"1\"\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eControl\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFS\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePS\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eP-value\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCS\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.18\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.02\u0026thinsp;\u0026plusmn;\u0026thinsp;0.01\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.026*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHTP\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.10\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.734NS\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eP-value\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.880NS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.018*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.012*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e*: significant (\u003cem\u003ep\u0026thinsp;\u0026le;\u003c/em\u003e\u0026thinsp;0.05); NS: non-significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eMean values with different superscript letters within the same row are significantly different.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eSurface morphology evaluation:\u003c/h2\u003e \u003cp\u003eThe surface morphology micrographs of the studied specimens at 800X are presented in (Fig.\u0026nbsp;3). Prior to smoking exposure, control group showed a rougher surface compared to both finishing and polishing groups which produced a more homogenous surface with the formation of a resin smear layer along with the presence of some multidirectional scratches.\u003c/p\u003e \u003cp\u003eAfter exposure to cigarette smoking, both finishing and polishing groups displayed smoother composite surfaces when compared to control group which showed an irregular surface topography. Deposition of organic materials on the surface was evident in all groups.\u003c/p\u003e \u003cp\u003eAfter exposure to HTP smoking, control group showed comparable surface changes with both finishing and polishing groups.\u003c/p\u003e "},{"header":"Discussion","content":"\u003cp\u003eColor change of resin composite materials could be generally caused by the following reasons: (1) extrinsic factors such as plaque accumulation, smoking and dietary habits[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]; (2) surface alterations related to type of finishing/polishing system promoting surface degradation and adsorption of coloring agents[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]; and (3) intrinsic factors related to chemical composition and alterations in matrix/filler interphase of the material[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Since dental esthetics is of great concern nowadays, and since one of the crucial reasons for composite restoration replacement is staining and color change, the purpose of the present study was to assess color stability and surface roughness of a supra-nanofilled resin composite submitted to different smoking products (with 0.5 mg nicotine) and finishing/polishing protocols.\u003c/p\u003e \u003cp\u003eIn literature, there are few studies evaluating the effect of heated tobacco products on resin-based restorations[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. In addition, not many studies have standardized the method of exposing restorative materials to cigarette smoke, such as the equipment design, number of cigarettes, smoke flow mechanism, smoke exposure time, simulation of oral cavity temperature and humidity[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan additionalcitationids=\"CR29\" citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. In contrast to these studies, the design methodology of the current study was to use a specially designed apparatus with a suction power capacity of 500 mL volume similar to tidal volume per each respiratory cycle during smoking. The apparatus received one cigarette at a time permitting simultaneous unidirectional smoke inhalation and exhalation in a standardized time interval and speed. In order to simulate the oral cavity, temperature was set to 37\u0026deg;C at 100% humidity by the aid of a thermal regulator.\u003c/p\u003e \u003cp\u003eRegarding color stability findings, a significant change in color (∆E\u0026thinsp;=\u0026thinsp;8.14\u0026ndash;11.93) was found in resin composite specimens exposed to conventional cigarettes, regardless of the finishing and polishing system, which was visually perceptible and considered clinically unacceptable.[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] On the contrary, all specimens exposed to heated tobacco products displayed a minor color change (∆E\u0026thinsp;=\u0026thinsp;2.31\u0026ndash;2.94), which was considered clinically acceptable.[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] Thus, the null hypothesis that smoking would have no effect on color stability of resin composite was partially rejected.\u003c/p\u003e \u003cp\u003eCigarette smoke is made up of a mixture of particulate and volatile components.[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] The particulate phase mainly consists of tar, while the volatile phase includes carbon monoxide, carbon dioxide, nitrogen monoxide and water. Tar represents more that 90% of smoke products. The tar precipitates on cigarette filters turning their color into yellow-brown, could be more likely the main agent causing discoloration of teeth and restorations.[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e] Upon combustion of those elements, dark pigments and metals like cadmium, arsenic, nickel and lead are released.[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e] Deposits of these elements may have adhered to top surfaces of composite specimens, resulting in staining and surface alterations.[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e] More darkening and yellowing of the specimens were observed for conventional cigarettes group compared to HTP group, interpreted by the significant reduction in L\u0026lowast; coordinate and increase in a\u0026lowast; and b\u0026lowast; coordinates. This agrees with a previous study showing a prominent discoloration effect of conventional cigarette smoke on artificial denture teeth in comparison to HTP smoke.\u003c/p\u003e \u003cp\u003eThe reduced staining potential of HTP could be attributed to the higher aerosols generated from heated sticks when compared to cigarette smoke.[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e] HTP device used in the current study consisted of a tobacco heating system different from the burning process that occurs with a lighted cigarette, thus producing less harmful ingredients. The combustion of conventional cigarettes may reach a temperature higher than 600\u0026deg;C,[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e] whereas HTP can be heated up to 350\u0026deg;C.[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e] When heated instead of burning, aerosols of suspended liquid droplets are liberated, thus eliminating the formation of any carbon-based solid particulates.[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e] These aerosols showed a different chemical composition, composed primarily of water, nicotine and glycerin.[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e] Nicotine is colorless in its original form, however, its oxidized state can cause yellowish staining.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] This might explain the reduced discoloration effect on specimens exposed to HTP smoke in comparison to conventional cigarette smoke, irrespective of the finishing/polishing protocol.\u003c/p\u003e \u003cp\u003eWithin conventional cigarettes groups, control specimens showed higher color change compared to both finishing and polishing groups. Meanwhile, there was no significant difference in ∆E values between control and finishing and polishing groups in heated tobacco products groups. Hence, the null hypothesis that finishing and polishing protocol would not affect color stability of resin composite was partially accepted. The fact that control specimens cured against polyester strip presented more staining than those submitted to either finishing and polishing protocol may be justified by the superior homogeneity of the composite surface resulting after finishing and polishing, rendering the surface more regular.[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] As proved in a previous study,[\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e] smoother composite surfaces produced from the adaptation of polyester strip are not necessarily more resistant to discoloration. In contrast, photo-polymerization of control specimens under pressure of polyester strip, may have created a superficial layer rich in organic matrix with lower filler loading.[\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e] Thus, this unpolished surface became unstable and have readily adsorbed the pigments emitted from the combustion products of cigarettes smoke. These findings came in accordance with those of a previous study which demonstrated an increased potential of cigarette smoke to stain all composite samples in the absence of polishing, along with increased surface roughness.[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eRegarding surface roughness, both smoking groups showed statistically similar mean change in Ra in control specimens. Whereas, specimens exposed to heated tobacco products showed significantly higher Ra mean change compared to conventional cigarettes in both finishing and polishing groups. Therefore, the null hypothesis that smoking would not affect composite surface roughness was partially rejected. As previously mentioned, the absence of finishing and polishing renders the composite surface more irregular and rougher owing to uneven matrix-filler distribution.[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] Since heated tobacco system heats tobacco without burning/combustion to release nicotine-containing aerosols, the composition of the aerosol is greatly different form the smoke liberated by combustible products of conventional cigarettes.[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e] IQOS aerosol primarily contains water which comprises more than 80%.[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e] Due to this high water content, aerosols formed from the condensation of water vapor caused wetting of composite surfaces. The hydrophilic character of TEGDMA monomer present in the composition of the tested resin composite is expected to increase water sorption.[\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e] The presence of Bis-GMA monomer which can also hydrogen bond to adsorbed water through its OH-groups.[\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e] Water acts as a polymer plasticizer, leading to hydrolytic degradation and surface deterioration of resin composite. Hence, adsorbed water could have weakened intermolecular bonds of resin matrix causing swelling of polymer network; minimizing frictional forces between polymer chains.[\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e] Moreover, a number of organic acids were identified in the total particulate matter of IQOS mainstream. The acidic pH of IQOS smoke originating from the combination of nicotine salts with organic acids,[\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e] resulting in protonation and release of H\u0026thinsp;+\u0026thinsp;ions which may have broken C-C bonds of polymer matrix as well as siloxane bonds connecting matrix to fillers; thereby releasing filler particles leading to exposure of resin matrix.[\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e] Besides thermal effects of emitted aerosols, this could have assumably contributed to increasing surface roughness values of all specimens in HTP groups.[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eAs for the conventional cigarettes groups, mean change in Ra values in control group was higher than two-step polishing system, followed by multi-step finishing system. On the contrary, no significant difference in Ra mean change between control and finishing and polishing groups when exposed to heated tobacco products. Hence, the null hypothesis that finishing and polishing protocol would have no influence on surface roughness was partially rejected. Our findings were in agreement with the study of Itanto et al.,[\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e] who reported an improved surface finish of a nanofilled composite resin after using a multi-step finishing system. This could be attributed to the flexibility, composition and technique of usage of the aluminum oxide discs.[\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e] The malleability of such discs promotes better adaptation and homogenous abrasion of both filler particles and resin matrix, preventing filler displacement from the matrix.[\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e] This system is also structured to be used in a sequential order of descending abrasiveness level, starting with coarse, medium, fine grains, and finalizing with felt discs in a unidirectional planar movement; hence favoring a final smoother surface texture. In the two-step polishing protocol, a pre-roughening step with diamond burs was performed, to simulate the clinical situation. The fine-grit yellow-coded abrasive burs equivalent to the coarse aluminium discs of the multi-step system were selected, in order to minimize scattering of the initial roughness values between both groups. This finishing step was followed by pre-polishing with medium-grain spiral, then final polishing with fine-grain spiral. Discoid shape polishers were used in the current study aiming to exclude the effect of tool geometry on surface roughness results.[\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e] Moreover, the specimens fabricated in this study were flat discs, which might be relatively easier for the wheel-shaped polishing tips to come in direct contact with the flat surface of the specimens, producing a high shine finish.[\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] It was also concluded in a former study that diamond particles impregnated within the flexible rubber material of the polishers have higher toughness and hardness than aluminium oxide and silicone carbide particles, which may have attributed to more homogenous abrasion and effective polishing.[\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e, \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e] These results came in accordance with those of Di Silva et al.,[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] who claimed that EVE Diacomp Twist Plus was effective in reducing surface roughness. However, theses findings did not follow those of Elgammal et al.,[\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e] who reported high surface roughness results with the two-step polishing system. This disparity could be related to the difference in the type of composite material tested, as they were using a bulk fill resin composite.\u003c/p\u003e \u003cp\u003eTo ensure standardization of finishing and polishing procedures, all steps were executed by the same operator following respective manufacturers\u0026rsquo; recommendations regarding speed and motion. Moreover, the applied pressure during polishing procedures was controlled at light pressure of approximately 30\u0026ndash;40 grams using a precision scale. A diamond polishing paste was used with final polishing step of both systems as several studies[\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e] proved its efficacy in providing a smoother and glossier surface finish. This is largely due to the great wear capacity of the diamond paste as diamond particles are harder than composite filler particles.[\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e] Consequently, this would enable equal and uniform removal of both composite phases, hence, minimizing surface roughness. This was supported by SEM photomicropraphs of conventional cigarettes group, which illustrated smoother surfaces of specimens subjected to both finishing and polishing systems when compared to control group. It seems that F/P systems created a resin smear layer on the composite surfaces with some multidirectional scratches. In the present study, all surface roughness values, irrespective to smoking or finishing and polishing protocol, were lower than 0.2 \u0026micro;m, which is the critical size for bacterial adhesion. These values were in accordance with the surface quality standard ISO 1302:2002.[\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eLimitations of the present study include lack of assessment of different brands and flavors, varying nicotine concentrations, and tooth brushing simulation during smoke exposure. Future studies are also recommended to investigate the effect of other commercially available finishing and polishing systems and polishing pastes with different particle sizes on color stability and surface topography of resin composite materials.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eUnder the limitations of the current study, it could be withdrawn that:\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eConventional cigarette smoking resulted in a pronounced color change in composite compared to heated tobacco product.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eSmoking of heated tobacco product produced an increased surface roughness compared to conventional cigarettes.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eBoth multi-step finishing system and two-step polishing system showed comparable color change and surface roughness in composite.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eFunding:\u003c/h2\u003e \u003cp\u003eOpen access funding provided by The Science, Technology \u0026amp; Innovation Funding Authority (STDF) in cooperation with The Egyptian Knowledge Bank (EKB).\u003c/p\u003e \u003cp\u003e \u003cb\u003eCompeting interests\u003c/b\u003e: Authors confirm that they have no conflict of interest.\u003c/p\u003e \u003cp\u003e\u003cb\u003eEthical approval and consent to participate\u003c/b\u003e: The research proposal was reviewed and approved by the Research and Ethics Committee of the Faculty of Dentistry, The British University in Egypt, with approval no. 24\u0026ndash;057.\u003c/p\u003e \u003cp\u003e\u003cb\u003eConsent for publication\u003c/b\u003e: Not applicable for this study.\u003c/p\u003e \u003cp\u003e \u003cb\u003eData availability\u003c/b\u003e: The data supporting the findings of the present study are available within the article.\u003c/p\u003e \u003cp\u003e \u003cb\u003eAuthors contribution\u003c/b\u003e: M.A. designed the smoking device and prepared the study design. M.S.S. conducted the practical work and specimens\u0026rsquo; preparation. M.S.S. \u0026amp; S.A.B. carried out measurements. S.A.B. conducted data collection and statistical analysis. S.A.B. \u0026amp; M.S.S. wrote the manuscript. M.S. \u0026amp; F.M. reviewed and proofread the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eZanetti F, Zhao X, Pan J, Peitsch MC, Hoeng J, Ren Y. Effects of cigarette smoke and tobacco heating aerosol on color stability of dental enamel, dentin, and composite resin restorations. Quintessence Int (Berlin). 2019;50(2):156\u0026ndash;66.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSulieman M. An overview of tooth discoloration: extrinsic, intrinsic and internalized stains. Dent Update. 2005;32(8):463.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMathias P, Costa L, Saraiva LO, Rossi TA, Cavalcanti AN, da, Nogueira-Filho R. G. 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Compendium Continuing Educ Dentistry. 2011;32(2):66\u0026ndash;70.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWasilewski Mde S, Takahashi MK, Kirsten GA, de Souza EM. Effect of cigarette smoke and whiskey on the color stability of dental composites. Am J Dent. 2010;23(1):4\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBaboni FB, Guariza Filho O, Moreno AN, Rosa EA. Influence of cigarette smoke condensate on cariogenic and candidal biofilm formation on orthodontic materials. Am J Orthod Dentofac Orthop. 2010;138(4):427\u0026ndash;34.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMcCann D. Tobacco use and oral health. J Am Dent Association. 1989;118(1):18\u0026ndash;25.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAyaz EA, Altintas SH, Turgut S. Effects of cigarette smoke and denture cleaners on the surface roughness and color stability of different denture teeth. J Prosthet Dent. 2014;112(2):241\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKurachi T, Chuman S, Suzuki T, Kubota T, Ishikawa S. Effects of Aerosols From Heated Tobacco Products With Flavors on the Discoloration of Bovine Tooth Enamel. Clin Experimental Dent Res. 2023;9(6):1069\u0026ndash;77.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWHO Heated Tobacco Products Information Sheet. (accessed on 20. February 2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePhilip Morris SA. IQOS explained, PMI website, undated, accessed December 2019.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBekki K, Inaba Y, Uchiyama S, Kunugita N. Comparison of Chemicals in Mainstream Smoke in Heat-not-burn Tobacco and Combustion Cigarettes. J UOEH. 2017;39(3):201\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePratte P, Cosandey S, Goujon Ginglinger C. Investigation of solid particles in the mainstream aerosol of the Tobacco Heating System THS2.2 and mainstream smoke of a 3R4F reference cigarette. Hum Exp Toxicol. 2017;36(11):1115\u0026ndash;20.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDhananjaya KM, Vadavadagi SV, Almalki SA, Verma T, Arora S, Kumar NN. In Vitro Analysis of Different Polishing Systems on the Color Stability and Surface Roughness of Nanocomposite Resins. J Contemp Dent Pract. 2019;20(11):1335\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAbo-Eldahab G, Kamel M, Nour K. The Effect of Different Polishing Methods on the Surface Roughness of Resin Composites (An In-Vitro Study). Egypt Dent J. 2022;68(4):4039\u0026ndash;51.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePatel SB, Gordan VV, Barrett AA, Shen C. The effect of surface finishing and storage solutions on the color stability of resin-based composites. J Am Dent Assoc. 2004;135(5):587\u0026ndash;94. quiz 654.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShintani H, Satou J, Satou N, Hayashihara H, Inoue T. Effects of various finishing methods on staining and accumulation of Streptococcus mutans HS-6 on composite resins. Dent Mater. 1985;1(6):225\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFeilzer YJ, Feilzer AJ, Noack MJ, Kleverlaan CJ. Release of contraction stress of dental resin composites by water sorption. Dent Mater. 2024;40(10):1697\u0026ndash;701.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYiu CK, King NM, Pashley DH, Suh BI, Carvalho RM, Carrilho MR, Tay FR. Effect of resin hydrophilicity and water storage on resin strength. Biomaterials. 2004;25(26):5789\u0026ndash;96.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHarvanko AM, Havel CM, Jacob P, Benowitz NL. Characterization of nicotine salts in 23 electronic cigarette refill liquids. Nicotine Tob Res. 2020;22(7):1239\u0026ndash;43.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChandra J, Setyowati L, Setyabudi. Surface roughness of nanofilled and ubah composite resins exposed to kretek cigarette smoke. Conservative Dentistry J. 2019;8(1):30\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eItanto BS, Usman M, Margono A. Comparison of surface roughness of nanofilled and nanohybrid composite resins after polishing with a multi-step technique. Journal of Physics: Conference Series. 2017;884(1):012091.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYap AU, Ng JJ, Yap SH, et al. Surface finish of resin-modified and highly viscous glass ionomer cements produced by new one-step systems. Operative Dentistry-University Wash. 2004;29(1):87\u0026ndash;91.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJefferies SR. Abrasive Finishing and Polishing in Restorative Dentistry: A State-of-the-Art Review. Dental Clin N Am. 2007;51(2):379\u0026ndash;97.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlbers HF. Placement and finishing. Tooth-colored restoratives: Principles and Techniques. 9th ed. London: BC Decker Inc.,Hamilton; 2002. pp. 162\u0026ndash;81.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFarzaneh F, Mohammadi-Bassir M, Rezvani MB, Dehestani Ardakani F. Effect of Chemical and Mechanical Degradation on Surface Roughness, Topography, Gloss, and Polish Retention of Three Composites Polished with Five Polishing Systems. Front Dentistry. 2021;18:39.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eElgammal YA, Temirek MM, Hassanein OE, Abdelaziz MM. The Effect of Different Finishing and Polishing Systems on Surface Properties of New Flowable Bulk-fill Resin Composite. J Contemp Dent Pract. 2023;24(8):587\u0026ndash;94.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLainović T, Blažić L, Kukuruzović D, Vilotić M, Ivanišević A, Kakaš D. Effect of Diamond Paste Finishing on Surface Topography and Roughness of Dental Nanohybrid Composites \u0026ndash; AFM Analysis. Procedia Eng. 2014;69:945\u0026ndash;51.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKurt A, Cilingir A, Bilmenoglu C, Topcuoglu N, Kulekci G. Effect of different polishing techniques for composite resin materials on surface properties and bacterial biofilm formation. J Dent. 2019;90:103199.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBusscher HJ, Rinastiti M, Siswomihardjo W, Vander Mei HC. Biofilm formation on dental restorative and implant materials. J Dent Res. 2010;89(7):657\u0026ndash;65.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Smoking, Cigarettes, Heated Tobacco Product, Finishing and Polishing, Color Stability, Surface Roughness, Resin Composite","lastPublishedDoi":"10.21203/rs.3.rs-6163357/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6163357/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eTo investigate the influence of smoking and finishing and polishing protocol on color stability and surface roughness of resin composite.\u003c/p\u003e\u003ch2\u003eMaterials and Methods\u003c/h2\u003e \u003cp\u003e Seventy-two discs fabricated from supra-nanofilled composite were divided to 6 groups according to: Tobacco Product (Conventional Cigarette/CS and Heated Tobacco/HTP); and Finishing and Polishing Protocol (Control/C, Multi-step finishing system/FS, and Medium-grit abrasive bur\u0026thinsp;+\u0026thinsp;two-step polishing system/PS). After finishing and polishing, specimens were exposed to total 600 cigarettes, divided to 20 each day, simulating 30 days of smoking. Color parameters were detected using a spectrophotometer. Surface roughness (Ra) was measured before and after smoking exposure using a surface roughness tester. Surface morphology was assessed under SEM. Data were analyzed using ANOVA/Tukey's and student t-test.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eFor CS, ∆E values of C group was significantly higher than both finishing/polishing groups, which were statistically similar. For HTP, no significant difference in ∆E values between all groups. ∆E values of CS were significantly higher than HTP in all groups. For CS, C group showed significantly higher change in Ra than FS group; whilst no significant difference in Ra change values of PS and those of C and FS groups. For HTP, no significant difference in Ra change between all groups. Within C group, Ra change of both smoking groups was statistically similar. Within FS and PS groups, change in Ra of HTP was significantly higher than CS.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eConventional cigarette smoking resulted in pronounced color change in composite. While, heated tobacco product produced an increased surface roughness. Both multi-step finishing system and two-step polishing system displayed comparable color change and surface roughness in composite.\u003c/p\u003e","manuscriptTitle":"Effect of Smoking and Finishing and Polishing Protocol on Color Stability and Surface Roughness of Resin Composite","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-04 08:45:55","doi":"10.21203/rs.3.rs-6163357/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-05-02T14:15:51+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-01T19:54:17+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"328378615034558024415175886020605125665","date":"2025-04-23T18:00:02+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-17T08:10:41+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-06T16:47:32+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"206122144125033843865950675212272429149","date":"2025-04-06T14:16:56+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"235252606889096557608735842587127100305","date":"2025-04-05T06:53:48+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-04-03T06:41:45+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-03-19T12:18:50+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-03-19T10:05:09+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-03-18T14:11:37+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Oral Health","date":"2025-03-18T14:10:26+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b600f165-d7cf-4419-820b-fc3709b20979","owner":[],"postedDate":"April 4th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-08T16:03:33+00:00","versionOfRecord":{"articleIdentity":"rs-6163357","link":"https://doi.org/10.1186/s12903-025-07161-1","journal":{"identity":"bmc-oral-health","isVorOnly":false,"title":"BMC Oral Health"},"publishedOn":"2025-12-05 15:58:16","publishedOnDateReadable":"December 5th, 2025"},"versionCreatedAt":"2025-04-04 08:45:55","video":"","vorDoi":"10.1186/s12903-025-07161-1","vorDoiUrl":"https://doi.org/10.1186/s12903-025-07161-1","workflowStages":[]},"version":"v1","identity":"rs-6163357","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6163357","identity":"rs-6163357","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}