|Year : 2022 | Volume
| Issue : 1 | Page : 74
The effect of hydrochloric acid and sodium hypochlorite on fracture resistance of orthodontic self-cure acrylic base
Saeed Noorollahian1, Atefeh Tabibi2
1 Department of Orthodontics, Dental Implants Research Center, Dental Research Institute, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
2 Department of Orthodontics, Faculty of Dentistry, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran
|Date of Submission||10-Jan-2021|
|Date of Acceptance||15-Sep-2021|
|Date of Web Publication||26-Sep-2022|
Dr. Atefeh Tabibi
Department of Orthodontics, Faculty of dentistry, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan
Source of Support: None, Conflict of Interest: None
Background: Patient cooperation is necessary for treatment success in removable orthodontics. Every factor has an adverse effect on appliances appearance can impede appliance wearing. This study investigated the effect of immersion in household cleaner and bleach liquids on fracture resistance of self-cure orthodontic acrylic resins.
Materials and Methods: This in vitro study two orthodontic acrylic resins (Megadental® and Acropars®) were used. Eighty identical acrylic samples (50 mm × 5 mm × 3 mm) from each acrylic resin were fabricated and divided into four groups (n = 20). For each type of acrylic resin; Group 1: 15 min immersion in household cleaner liquid (hydrochloric acid [HCl], 10%), 1 min rinsing with running water, 15 min immersion in household bleach liquid (sodium hypochlorite [NaOCl], 5.25%) and 1 min rinsing with running water were done. For Group 2, two times and for Group 3, three times immersion just like Group 1, were done. Group 4, as control, had no immersion. Fracture resistance of samples was measured with universal testing machine (Instron) in 3-point bending set-up. Data were analyzed with two-way repeated measurement ANOVA. Significance level was set at 0.05.
Results: Fracture resistance of Acropars groups was greater than counterpart Megadental ones (P < 0.001). Immersion factor, alone (P = 0.375) and in combination with material (P = 0.603), did not make a significant difference among fracture resistance of each acrylic resin groups.
Conclusion: 15 min immersion in household cleaner liquid (HCl acid) followed by 15 min immersion in household bleach liquid (NaOCl 5.25%) and even 3 times repetition of this process had not significant adverse effect on fracture resistance of acrylic resins.
Keywords: Fracture Resistance, orthodontic removable appliances, self-cure acrylic base
|How to cite this article:|
Noorollahian S, Tabibi A. The effect of hydrochloric acid and sodium hypochlorite on fracture resistance of orthodontic self-cure acrylic base. Dent Res J 2022;19:74
|How to cite this URL:|
Noorollahian S, Tabibi A. The effect of hydrochloric acid and sodium hypochlorite on fracture resistance of orthodontic self-cure acrylic base. Dent Res J [serial online] 2022 [cited 2022 Dec 6];19:74. Available from: https://www.drjjournal.net/text.asp?2022/19/1/74/356807
| Introduction|| |
Providing and maintaining the cooperation of orthodontic patients are cornerstone of the success of removable orthodontic treatments., The esthetic appearance of the appliance is one of the effective means for making and maintaining motivation, especially for children. Color changes, unpleasant smell, sedimentation of calcareous materials, and any other factors which result in an unpleasant appearance for the removable appliance can reduce the patient's tendency to use them. Insufficient knowledge or weak cooperation of the patient in cleaning the appliance will further exacerbate these problems.,
The microorganisms in the oral cavity are capable to attach themselves on any external body and growing on it. Some like Candida can infiltrate the acrylic bases. Colonization of micro-organisms is more frequent on those surfaces of the plate which contact the mucous or dental surfaces. The moist environment of the oral cavity and keeping the appliance in water help the microorganisms to grow on the surface of the orthodontic plates.,
Cleaning with only water is not an efficient method for cleaning the plate., The most frequently recommended method for cleaning an acrylic base is mechanical cleaning using only toothbrush or toothbrush together with detergent.,,,, Some experts have reported this method even more efficient than that with using solutions of cleaning tablets., Some have demonstrated that using toothbrush only is not as effective as using chemical cleaners in reducing bio-film on acrylic bases., Some others do not consider either of the methods more efficient than the others. Some regard a combination of both methods as the most efficient one. Using toothpastes or other abrasive materials is not recommended due to their effect in reducing the surface smoothness. Micro-wave disinfection is also recommended for cleaning acrylic bases, even though it has proved to be most effective when combined with toothbrush and cleaning tablet methods.
Easy application, antimicrobial properties, absence of negative effects on the structure, appearance, and hardness of the acrylic base, along with the ability to remove organic matter, added colors, odors, and minerals from the plates are essential properties of an ideal cleaner.,,
Hydrochloric acid (HCl) is a strong acid. The weakened form of it is used in household cleaners (10%) and for eliminating calcareous sediments from different surfaces. This solution is also used in dentistry for eliminating the color changes of the enamel through micro-abrasion method. Sodium hypochlorite (NaOCl) is an inexpensive oxidizer which is frequently used as a household bleaching liquid (5.25%). This solution also has decolorizing and deodorant properties. Even in low concentrations, it is a strong disinfecting agent for the surfaces, nonmetal objects, and dental casts.,,,, Due to its antibacterial properties, it is also used as a cleaning solution in root canal treatments.,
Considering the possibility of using HCl acid for eliminating minerals from the surface of orthodontic removable appliances and subsequently using NaOCl for eliminating unpleasant smell and color, this research aims to assess the effect of immersing in household cleaner solution (with 10% HCl-acid) and subsequently immersing in household bleaching liquid (5.25% NaOCl) on the fracture resistance of two types of orthodontic self-cure acrylic bases.
| Materials and Methods|| |
This in vitro study was approve in research and ethics committee of Isfahan (NO:295094). Two types of orthodontic self-cure acrylic bases were used in this research: (1) Megadental (GmbH, D-63654, Budingen, Germany) and (2) OP Acropars (Marlic, Tehran, Iran).
For preparing acrylic parts with the same dimensions, a computer numerical control machine was used on a steel ingot to create molds with 50, 3, and 5 mm of length, depth, and width [Figure 1]. Eighty acrylic pieces were made out of each type of acryl based on the manufacturers' instructions. After being kept in physiological serums in room temperature for 24 h, samples of each type of acryl were randomly divided into four groups of 20. Then, they entered the immersion process in room temperature separately. Household cleaner solution (Active®, Padideh Shimi Gharn Co., Tehran, Iran) was used as the solution containing 10% HCl acid and household bleaching solution (Active®, Padideh Shimi Gharn Co., Tehran, Iran) containing 5.25% NaOCl.
|Figure 1: Metal molds to prepare acrylic resin bars with equal dimensions.|
Click here to view
For each type of acryl in Group 1, 15 min of immersing in the cleaner liquid, 1 min of washing with flowing water, 15 min of immersing in the bleaching liquid, and then 1 min of washing with flowing water were carried out. The same process was carried out twice for Group 2 and three times for Group 3. Group 4 as the control group did not undergo any immersion. Finally, all of the samples were dried using a cotton towel. For blinding the research, the samples were coded by first author and then measurements were done with second author. The fracture resistance of the samples was measured using the Instron® Universal Testing Machine (MA, USA) in a 3 point bending manner with a 0.5 mm/s speed [Figure 2]. The data were analyzed using SPSS (Version 22, Chicago, USA, IBM Corp) with two-way repeated measured ANOVA test with a 0.05 significance level.
| Results|| |
The mean and standard error for fracture resistance of different groups of both materials are listed in [Table 1]. These results are also shown in [Figure 3]. The analysis of two-way repeated measured ANOVA showed that the mean fracture resistance in all Acropars acryl groups was significantly higher compared to the corresponding Megadental groups (P < 0.001). The immersion times variable, either alone (P = 0.375) or combined with the material variable (P = 0.623), results in no significant change in the fracture resistance of the groups of each type of acryl.
|Table 1: Mean and standard error of fracture resistance (Newton) in different groups (newton)|
Click here to view
|Figure 3: The mean of fracture resistance of different groups of both materials (Control: without Immersion; Group 1: One time immersion; Group 2: Two immersions; Group 3: Three times immersion).|
Click here to view
| Discussion|| |
Orthodontic removable has the potential of food debris retention and help the microbial plaque growth; therefore, cleaning the appliance and maintaining the oral hygiene are important.,, Sedimentation of calcareous materials on the removable appliance, not only brings about an unpleasant appearance, but also increases the surface roughness and microbial growth and makes it more difficult to keep it clean. These sediments can also spoil the conformity of appliance in areas which contact the teeth. This brings about the possibility of unwanted movement in dental retainers.
Two types of acryl were used in this research to help to generalize the findings. The results of this research show that immersion in 10%-HCl acid and subsequently in 5.25%-NaOCl, each for 15 min, does not result in significant change of the fracture resistance of acrylic bases, even if carried out for up to three times. Repeating the process for three times showed that the acrylic base will not suffer serious damage even after 45 min of immersion in the mentioned solutions. This confirms the safety of this method of immersion in fewer times and for shorter durations. At the time of this study, no researches had analyzed the effect of HCl on acrylic bases. HCl is not listed as a cleaning solution, but NaOCl is considered an affective one even in low concentrations. Even 0.02% of this solution is effective on Candida. The most effective cleaning solution for preventing the growth of microbial biofilms and colonization of Candida is 0.5% NaOCl. 1% NaOCl can eliminate the common micro-organisms in the oral cavity even in 10 s. In 2017, Pires et al. mentioned 1% NaOCl to be a suitable solution for disinfecting acrylic bases. Therefore, the method suggested in the current study can also be applied for disinfecting orthodontic plate and eliminating microbial colonization.
In this regard, sedimentation in solutions such as diluted vinegar, diluted NaOCl, or shaker bathing method with a detergent are also recommended. Moreover, Sodium perborate and 0.2% and 0.12% chlorhexidine are also preferable solutions for sedimentation.,,,,,, Microwaving with a power of 450 to 650 wats for 3 min is also recommended for disinfecting acrylic bases, but temperatures above 70° of centigrade will increase the deformation possibility. As a solution for this problem, a combination of microwaving method and cleaners available in market is recommended, though placing orthodontic appliances or tooth sets in the microwave might displease the other members of the family.
NaOCl has little destructive effects on acrylic bases. Also reduction of micro-hardness of acrylic bases as a result of 1% hypochlorite Sodium in 90 cycles of 10 s has been reported. Arruda et al. however did not report any significant change in the hardness of the surface after 1 year of daily immersion in 0.5% hypochlorite or 20 min. Some studies reported that 1% and 0.5% NaOCl does not result in the surface roughness changes of acrylic bases., according to the study of Sharma et al., immersion of heat curing resin samples for 3 months in 1%-NaOCl, increases surface roughness. Other studies have not reported any effect of 0.5% NaOCl (90 days of immersion, 3 min for each day and simulating a 1-year immersion, 20 min or each day, on the smoothness of significant surfaces. Although, some market cleaners may reduce the smoothness of the surfaces of acrylic bases. Sharma et al. reported that, the use of 1% NAOCL for 3 months reduced the flexural strength of denture base resin. Letícia Resende Davi et al. demonstrated that the 1% NaOCl during the simulated period of 180 days presented significantly lower flexural strength of polymerized acrylic resin compared with the control group. In short disinfection simulations, NaOCl solutions at 1%, 2.5% and 5.25% concentrations did not change the flexural strength of the acrylic resin. Kurt et al. Also showed that the flexural strength of samples kept in 1% hypochlorite for 7 days were comparable with the control group.
According to other studies, NaOCl (1%, 3 times a day, 30 min each time, for 30 days) and (0.5%, simulating 1 year of immersion, 20 min a day) will not result in any changes in the fracture resistance of acrylic bases. This is also confirmed in the current study in which immersion was carried out with 5.25% NaOCl for 15 min for up to 3 times.
Color stability is regarded a desired property for acrylic bases. Insufficient polymerization, surface roughness, consumption of colored foods and beverages such as tea, coffee, or juices can result in color changes of acrylic bases. Although the lower the pH of the foods or drinks is, the more its effects will be on color changes. While In 2015, Shah et al. Reported that immersion in basic denture cleaning solutions caused the most base color discoloration, which was time-dependent. Considering the fact that the acrylic base of removable orthodontic appliances is made of self-curing acryl, these bases have less resistance against color changes compared to tooth sets. This is while some have reported the resistance of self-curing acryl against external colors to be more. Another aspect of color stability is the property to maintain the initial color against the process of cleaning. Although market cleaners are affective for eliminating the external colors caused by foods or drinks, some can affect the initial color of the acrylic base in long term. Panariello et al. have demonstrated that 1%-NaOCl causes a slight change in the initial color of acrylic bases in 90 cycles of 10 s. Although other studies have not reported any significant change in the initial color of the acrylic bases resulted by use of NaOCl (0.5%, 90 days, 3 min and simulation of 1 year of immersion, 20 min a day). Although we did not systematically analyze the effect of immersion in HCl acid and hypochlorite Sodium in the current study, we did not observe any significant change in the color. Confirming or denying this requires us to design another research.
0.05% NaOCl does not result in significant ions release from metal structures. Although, it can bring about unpleasant results like stains or corrosion (pitting in the surface) on metal surfaces such as the chrome-cobalt framework or orthodontic wires.,, HCl acid has corrosive effect on metals. The average concentration of HCl acid used in household cleaners is 10%. Moreover, household cleaners contain organic materials which act as preventers that reduce the corrosive property of the acid. Analyzing the effect of immersion of orthodontic plate, following the method introduced in the current study, on the metal components of the plate, requires further research.
| Conclusion|| |
Fifteen minutes of immersion in a household cleaner solution (10% HCl acid) and subsequently 15 min of immersion in a household bleaching liquid (5.25%-NaOCl) and even 3 times repetition of this process does not result in significant reduction of fracture resistance in acrylic bases even up to three times repetitions.
Financial support and sponsorship
Conflicts of interest
The authors of this manuscript declare that they have no conflicts of interest, real or perceived, financial or nonfinancial in this article.
| References|| |
Daniels AS, Seacat JD, Inglehart MR. Orthopedics D. Orthodontic treatment motivation and cooperation: A cross-sectional analysis of adolescent patients' and parents' responses. Am J Orthod Dentofacial Orthop 2009;136:780-7.
Slakter MJ, Albino JE, Fox RN, Lewis EA. Reliability and stability of the orthodontic patient cooperation scale. Am J Orthod 1980;78:559-63.
Feu D, Catharino F, Duplat CB, Capelli J Jr. Esthetic perception and economic value of orthodontic appliances by lay Brazilian adults. Dental Press J Orthod 2012;17:102-14.
Eichenauer J, Serbesis C, Ruf S. Cleaning removable orthodontic appliances: A survey. J Orofac Orthop 2011;72:389-95.
Shpack N, Greenstein RB, Gazit D, Sarig R, Vardimon AD. Efficacy of three hygienic protocols in reducing biofilm adherence to removable thermoplastic appliance. Angle Orthod 2014;84:161-70.
Mousavi SM, Ghorani PS, Javidi P, Berahman N, Moattari M. The effect of time and three different storage environments on the dimensional stability of acrylic removable orthodontic appliances. Biosci Biotechnol Res Asia 2015;12:2319-24.
Panariello BH, Izumida FE, Moffa EB, Pavarina AC, Jorge JH, Giampaolo ET. Effects of short-term immersion and brushing with different denture cleansers on the roughness, hardness, and color of two types of acrylic resin. Am J Dent 2015;28:150-6.
Lessa FC, Enoki C, Ito IY, Faria G, Matsumoto MA, Nelson-Filho P. In vivo
evaluation of the bacterial contamination and disinfection of acrylic baseplates of removable orthodontic appliances. Am J Orthod Dentofacial Orthop 2007;131:705.e11-7.
Levrini L, Mangano A, Margherini S, Tenconi C, Vigetti D, Muollo R, et al.
ATP bioluminometers analysis on the surfaces of removable orthodontic aligners after the use of different cleaning methods. Int J Dent 2016;2016:5926941.
Peixoto IT, Enoki C, Ito IY, Matsumoto MA, Nelson-Filho P. Evaluation of home disinfection protocols for acrylic baseplates of removable orthodontic appliances: A randomized clinical investigation. Am J Orthod Dentofacial Orthop 2011;140:51-7.
Levrini L, Novara F, Margherini S, Tenconi C, Raspanti M. Scanning electron microscopy analysis of the growth of dental plaque on the surfaces of removable orthodontic aligners after the use of different cleaning methods. Clin Cosmet Investig Dent 2015;7:125-31.
Nicholson RJ, Stark MM, Scott HE Jr. Calculus and stain removal from acrylic resin dentures. J Prosthet Dent 1968;20:326-9.
Fathi H, Martiny H, Jost-Brinkmann PG. Efficacy of cleaning tablets for removable orthodontic appliances: An in vivo
pilot study. J Orofac Orthop 2015;76:143-51.
Paranhos HF, Silva-Lovato CH, Souza RF, Cruz PC, Freitas KM, Peracini A. Effects of mechanical and chemical methods on denture biofilm accumulation. J Oral Rehabil 2007;34:606-12.
Tarbet WJ, Axelrod S, Minkoff S, Fratarcangelo PA. Denture cleansing: A comparison of two methods. J Prosthet Dent 1984;51:322-5.
Moore TC, Smith DE, Kenny GE. Sanitization of dentures by several denture hygiene methods. J Prosthet Dent 1984;52:158-63.
Taylor R, Maryan C, Verran J. Retention of oral microorganisms on cobalt-chromium alloy and dental acrylic resin with different surface finishes. J Prosthet Dent 1998;80:592-7.
Duyck J, Vandamme K, Krausch-Hofmann S, Boon L, De Keersmaecker K, Jalon E, et al.
Impact of denture cleaning method and overnight storage condition on denture biofilm mass and composition: A cross-over randomized clinical trial. PLoS One 2016;11:e0145837.
de Oliveira DT, de Almeida MT, Rezende MC, de Magalhães Bertoz AP, Bigliazzl R, Bertoz FA. Effect of polymerization techniques and cleaning solution on flexural resistance of acrylic resin chemically activated. J Dent Oral Hyg 2015;7:28-32.
Sesma N, Rocha AL, Laganá DC, Costa B, Morimoto S. Effectiveness of denture cleanser associated with microwave disinfection and brushing of complete dentures: In vivo
study. Braz Dent J 20123;24:357-61.
Al-Huraishi H, Moran J, Jagger R, MacDonald E. Evaluation of stain removal and inhibition properties of eight denture cleansers: An in vitro
study. Gerodontology 2013;30:10-7.
Backenstose WM, Wells JG. Side effects of immersion-type cleansers on the metal components of dentures. J Prosthet Dent 1977;37:615-21.
Maart R, Grobler S, Kruijsse H, Osman Y, Patel N, Moodley DS. The whitening effect of four different commercial denture cleansers on stained acrylic resin. J S Afr Dent Assoc 2016;71:106-11.
Bassir MM, Bagheri G. Comparison between phosphoric acid and hydrochloric acid in microabrasion technique for the treatment of dental fluorosis. J Conserv Dent 2013;16:41-4.
] [Full text]
Gallandat K, Wolfe MK, Lantagne D. Surface cleaning and disinfection: Efficacy assessment of four chlorine types using escherichia coli and the ebola surrogate Phi6. Environ Sci Technol 2017;51:4624-31.
Ronco C, Mishkin GJ. Disinfection by Sodium Hypochlorite: Dialysis Applications. New York: Karger; 2007.
Webb BC, Thomas CJ, Whittle T. A 2-year study of Candida-associated denture stomatitis treatment in aged care subjects. Gerodontology 2005;22:168-76.
Poulis N, Prombonas A, Yannikakis S, Karampotsos T, Katsarou MS, Drakoulis N. Preliminary SEM observations on the surface of elastomeric impression materials after immersion or ozone disinfection. J Clin Diagn Res 2016;10:C01-5.
Priyank H, Pandey V, Bagul A, Majety KK, Verma P, Choudhury BK. Evaluation of 4% sodium hypochlorite in eliminating Enterococcus faecalis
from the root canal when used with three irrigation methods: An in vitro
study. J Contemp Dent Pract 2017;18:214-7.
Valverde ME, Baca P, Ceballos L, Fuentes MV, Ruiz-Linares M, Ferrer-Luque CM. Antibacterial efficacy of several intracanal medicaments for endodontic therapy. Dent Mater J 2017;36:319-24.
Salles MM, Badaró MM, Arruda CN, Leite VM, Silva CH, Watanabe E, et al.
Antimicrobial activity of complete denture cleanser solutions based on sodium hypochlorite and Ricinus communis
– A randomized clinical study. J Appl Oral Sci 2015;23:637-42.
Panariello BH, Izumida FE, Moffa EB, Pavarina AC, Jorge JH, Giampaolo ET. Effect of mechanical toothbrushing combined with different denture cleansers in reducing the viability of a multispecies biofilm on acrylic resins. Am J Dent 2016;29:154-60.
Pires CW, Fraga S, Beck AC, Braun KO, Peres PE. Chemical methods for cleaning conventional dentures: What is the best antimicrobial option? An in vitro
study. Oral Health Prev Dent 2017;15:73-7.
Jeyapalan K, Kumar JK, Azhagarasan NS. Comparative evaluation of the effect of denture cleansers on the surface topography of denture base materials: An in vitro
study. J Pharm Bioallied Sci 2015;7:S548-53.
Kumar MN, Thippeswamy HM, Raghavendra Swamy KN, Gujjari AK. Efficacy of commercial and household denture cleansers against Candida albicans
adherent to acrylic denture base resin: An in vitro
study. Indian J Dent Res 2012;23:39-42.
Wang W, Hou Y, Li J, Zhu Y, Tang X, Ai H. Effect of different denture cleaning methods on roughness in resin denture base. Zhong Nan Da Xue Xue Bao Yi Xue Ban 2013;38:1065-9.
Senna PM, Sotto-Maior BS, Silva WJ, Del Bel Cury AA. Adding denture cleanser to microwave disinfection regimen to reduce the irradiation time and the exposure of dentures to high temperatures. Gerodontology 2013;30:26-31.
Kiesow A, Sarembe S, Pizzey RL, Axe AS, Bradshaw DJ. Material compatibility and antimicrobial activity of consumer products commonly used to clean dentures. J Prosthet Dent 2016;115:189-98.e8.
Arruda CN, Sorgini DB, Oliveira Vde C, Macedo AP, Lovato CH, Paranhos Hde F. Effects of denture cleansers on heat-polymerized acrylic resin: A five-year-simulated period of use. Braz Dent J 2015;26:404-8.
Lima EM, Moura JS, Del Bel Cury AA, Garcia RC, Cury JA. Effect of enzymatic and NaOCl treatments on acrylic roughness and on biofilm accumulation. J Oral Rehabil 2006;33:356-62.
Sharma P, Garg S, Kalra NM. Effect of denture cleansers on surface roughness and flexural strength of heat cure denture base resin – An in vitro
study. J Clin Diagn Res 2017;11:C94-7.
de Sousa Porta SR, de Lucena-Ferreira SC, da Silva WJ, Del Bel Cury AA. Evaluation of sodium hypochlorite as a denture cleanser: A clinical study. Gesrodontology 2015;32:260-6.
Sorgini DB, da Silva-Lovato CH, Muglia VA, de Souza RF, de Arruda CN, Paranhos Hde F. Adverse effects on PMMA caused by mechanical and combined methods of denture cleansing. Braz Dent J 2015;26:292-6.
Cakan U, Kara O, Kara HB. Effects of various denture cleansers on surface roughness of hard permanent reline resins. Dent Mater J 2015;34:246-51.
Davi LR, Peracini A, Ribeiro Nde Q, Soares RB, da Silva CH, Paranhos Hde F, et al.
Effect of the physical properties of acrylic resin of overnight immersion in sodium hypochlorite solution. Gerodontology 2010;27:297-302.
Pavarina AC, Machado AL, Giampaolo ET, Vergani CE. Effects of chemical disinfectants on the transverse strength of denture base acrylic resins. J Oral Rehabil 2003;30:1085-9.
Kurt A, Erkose-Genc G, Uzun M, Sarı T, Isik-Ozkol G. The effect of cleaning solutions on a denture base material: Elimination of Candida albicans
and alteration of physical properties. J Prosthodont 2018;27:577-83.
Hollis S, Eisenbeisz E, Versluis A. Color stability of denture resins after staining and exposure to cleansing agents. J Prosthet Dent 2015;114:709-14.
Shah VR, Shah DN, Chauhan CJ, Doshi PJ, Kumar A. Evaluation of flexural strength and color stability of different denture base materials including flexible material after using different denture cleansers. J Indian Prosthodont Soc 2015;15:367-73.
] [Full text]
Vafaee F, Mohammadi A, Khoshhal M, Allahbakhshi H, Mehr HR. A Comparative study of heat and self-cured acrylic resins on color stability of 5 brands of denture teeth. Avicenna J Dent Res 2016;8: e30328.
Imirzalioglu P, Karacaer O, Yilmaz B, Ozmen Msc I. Color stability of denture acrylic resins and a soft lining material against tea, coffee, and nicotine. J Prosthodont 2010;19:118-24.
Hong G, Murata H, Li Y, Sadamori S, Hamada T. Influence of denture cleansers on the color stability of three types of denture base acrylic resin. J Prosthet Dent 2009;101:205-13.
Davi LR, Felipucci DN, de Souza RF, Bezzon OL, Lovato-Silva CH, Pagnano VO, et al.
Effect of denture cleansers on metal ion release and surface roughness of denture base materials. Braz Dent J 2012;23:387-93.
Medina-Ramón M, Zock JP, Kogevinas M, Sunyer J, Torralba Y, Borrell A, et al.
Asthma, chronic bronchitis, and exposure to irritant agents in occupational domestic cleaning: A nested case-control study. Occup Environ Med 2005;62:598-606.
Kord L, Nasr-Esfahani M. Corrosion behavior of carbon steel in HCl solution by Fe and Cr complexes with a Schiff-base ligand derived from salicylaldehyde and 2-(2-aminoethylamino) ethanol. Surf Eng ApplElectrochemistry SurfEng Applied Electrochem 2015;51:491-500.
[Figure 1], [Figure 2], [Figure 3]