Journal of Prosthetic Dentistry
Research and Education| Volume 129, ISSUE 2, P364.e1-364.e9, February 2023

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Hardness and surface roughness of differently processed denture base acrylic resins after immersion in simulated gastric acid


      Statement of problem

      The effect of gastric acid on the surface properties of denture base acrylic resin is unknown.


      The purpose of this in vitro study was to evaluate changes in the surface roughness and hardness of denture base acrylic resins after immersion in simulated gastric acid.

      Material and methods

      Acrylic resin specimens (n=10) were prepared with 3 different processing techniques (compression-molded, injection-molded, and computer-aided design and computer-aided manufacturing [CAD-CAM] milled) and exposed to either gastric acid or artificial saliva (control). Surface roughness and hardness were measured at baseline (T0) and after 24-hour (T24) and 96-hour (T96) immersion in the solutions. The surface roughness and hardness data were analyzed by 3-way ANOVA and the Tukey HSD test (α=.05).


      At T24, the greatest change in surface hardness was observed for compression-molded specimens in gastric acid (P<.05). At T96, changes in hardness values were higher in compression-molded specimens than those in milled specimens (P<.05). Regarding surface roughness, at T24, compression-molded and injection-molded specimens showed higher values than milled specimens in gastric acid (P<.05). Concerning specimens in artificial saliva, compression-molded specimens showed significantly higher changes in roughness than those of the others (P<.05). At T96, injection-molded specimens had the greatest roughness values (P<.05). Among specimens immersed in artificial saliva, milled specimens showed lower roughness values than the injection-molded or compression-molded specimens (P<.05).


      Gastric acid exposure adversely affected the roughness and hardness of all the acrylic resins evaluated. CAD-CAM milled specimens showed better resistance to acid exposure after 24 and 96 hours in terms of roughness and hardness.
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        • Rueggeberg F.A.
        From vulcanite to vinyl, a history of resins in restorative dentistry.
        J Prosthet Dent. 2002; 87: 364-379
        • Babu M.R.
        • Rao C.S.
        • Ahmed S.T.
        • Bharat J.S.V.
        • Rao N.V.
        • Vinod V.
        A comparative evaluation of the dimensional accuracy of heat polymerized PMMA denture base cured by different curing cycles and clamped by RS technique and conventional method—an in-vitro study.
        J Int Oral Health. 2014; 6: 68-75
        • Hashem M.
        • Alsaleem S.O.
        • Assery M.K.
        • Abdeslam E.B.
        • Vellappally S.
        • Anil S.
        A comparative study of the mechanical properties of the light-cure and conventional denture base resins.
        Oral Health Dent Manag. 2014; 13: 311-315
        • Ali U.
        • Bt.Karim K.J.
        • Buang N.A.
        A review of the properties and applications of poly(methyl methacrylate) (PMMA).
        Polymer Reviews. 2015; 55: 678-705
        • Al-Qarni F.D.
        • Goodacre C.J.
        • Kattadiyil M.T.
        • Baba N.Z.
        • Paravina R.D.
        Stainability of acrylic resin materials used in CAD-CAM and conventional complete dentures.
        J Prosthet Dent. 2020; 123: 880-887
        • Al-Dwairi Z.N.
        • Tahboub K.Y.
        • Baba N.Z.
        • Goodacre C.J.
        • Özcan M.A.
        Comparison of the surface properties of CAD-CAM and conventional polymethylmethacrylate (PMMA).
        J Prosthodont. 2019; 28: 452-457
        • Gharechahi J.
        • Asadzadeh N.
        • Shahabian F.
        • Gharechahi M.
        Dimensional changes of acrylic resin denture bases: conventional versus injection-molding technique.
        J Dent (Tehran). 2014; 11: 398-405
        • Lee S.Y.
        • Lai Y.L.
        • Hsu T.S.
        Influence of polymerization conditions on monomer elution and microhardness of auto polymerized polymethyl methacrylate resin.
        Eur J Oral Sci. 2002; 110: 179-183
        • Srinivasan M.
        • Gjengedal H.
        • Cattani-Lorente M.
        • et al.
        CAD-CAM milled complete removable dental prostheses: an in vitro evaluation of biocompatibility mechanical properties and surface roughness.
        Dent Mater J. 2018; 37: 526-533
        • Jackson A.D.
        • Lang B.R.
        • Wang R.F.
        The influence of teeth on denture base processing accuracy.
        Int J Prosthodont. 1993; 6: 333-340
        • Pryor W.J.
        Injection molding of plastics for dentures.
        J Am Dent Assoc. 1942; 29: 1400-1408
        • Memon M.S.
        • Yunus N.
        • Razak A.A.A.
        Some mechanical properties of a highly cross-linked microwave-polymerized injection-molded denture base polymer.
        Int J Prosthodont. 2021; 14: 214-218
        • Polat T.
        • Karacaer Ö.
        • Tezvergil A.
        • Lassila L.V.J.
        • Vallittu P.K.
        Water sorption solubility and dimensional changes of denture base polymers reinforced with short glass fibers.
        J Biomater Appl. 2003; 17: 321-335
        • Phoenix R.D.
        • Mansueto M.A.
        • Ackerman N.A.
        • Jones R.E.
        Evaluation of mechanical and thermal properties of commonly used denture base resins.
        J Prosthodont. 2004; 13: 17-27
        • Levin B.
        • Sanders J.L.
        • Reitz P.V.
        The use of microwave energy for processing acrylic resins.
        J Prosthet Dent. 1989; 61: 381-383
        • Infante L.
        • Yilmaz B.
        • McGlumphy E.
        • Finger I.
        Fabricating complete dentures with CAD-CAM technology.
        J Prosthet Dent. 2014; 111: 351-355
        • Steinmassl O.
        • Dumfahrt H.
        • Grunert I.
        • Steinmassl P.A.
        CAD-CAM produces dentures with improved fit.
        Clin Oral Investig. 2018; 22: 2829-2835
        • Baba N.Z.
        CAD-CAM complete denture systems and physical properties: a review of the literature.
        J Prosthodont. 2021; 30: 113-124
        • Al-Fouzan A.F.
        • Al-mejrad L.A.
        • Albarrag A.M.
        Adherence of candida to complete denture surfaces in vitro: a comparison of conventional and CAD-CAM complete dentures.
        J Adv Prosthodont. 2017; 9: 402-408
        • Murat S.
        • Alp G.
        • Alatalı C.
        • Uzun M.
        In vitro evaluation of adhesion of candida albicans on CAD-CAM PMMA-based polymers.
        J Prosthodont. 2019; 28: e873-e879
        • Ayman A.D.
        The residual monomer content and mechanical properties of CADCAM resins used in the fabrication of complete dentures as compared to heat cured resins.
        Electron Physician. 2017; 9: 4766-4772
        • Perea-Lowery L.
        • Minja I.K.
        • Lassila L.
        • Ramakrishnaiah R.
        • Vallittu P.K.
        Assessment of CAD-CAM polymers for digitally fabricated complete dentures.
        J Prosthet Dent. 2021; 125: 175-181
        • Becerra J.
        • Mainjot A.
        • Hüe O.
        • Sadoun M.
        • Nguyen J.F.
        Influence of high-pressure polymerization on mechanical properties of denture base resins.
        J Prosthodont. 2021; 30: 128-134
        • Ali I.L.
        • Yunus N.
        • Abu-Hassan M.I.
        Hardness flexural strength and flexural modulus comparisons of three differently cured denture base systems.
        J Prosthodont. 2008; 17: 545-549
        • Kattadiyil M.T.
        • Jekki R.
        • Goodacre C.J.
        • Baba N.Z.
        Comparison of treatment outcomes in digital and conventional complete removable dental prosthesis fabrications in a predoctoral setting.
        J Prosthet Dent. 2015; 114: 818-825
        • Batisse C.
        • Nicolas E.
        Comparison of CAD-CAM and conventional denture base resins: a systematic review.
        Appl Sci. 2021; 11: 5990
        • Goiato M.C.
        • dos Santos D.
        • Moreno A.
        • Iyda M.G.
        • Rezende M.C.R.A.
        • Haddad M.F.
        Effect of disinfection and storage on the flexural strength of ocular prosthetic acrylic resins.
        J Gerodontol. 2012; 29: e838-e844
        • Bitencourt S.B.
        • Catanoze I.A.
        • daSilva E.V.F.
        • et al.
        Effect of acidic beverages on surface roughness and color stability of artificial teeth and acrylic resin.
        J Adv Prosthodont. 2020; 12: 55-60
        • Goiato M.C.
        • Dos Santos D.M.
        • Andreotti A.M.
        • et al.
        Effect of beverages and mouthwashes on the hardness of polymers used in intraoral prostheses.
        J Prosthodont. 2014; 23: 559-564
        • Rode K.M.
        • de Freitas P.M.
        • Lloret P.R.
        • Powell L.G.
        • Turbino M.L.
        Micro-hardness evaluation of a micro-hybrid composite resin light-cured with halogen light, light-emitting diode and argon ion laser.
        Lasers Med Sci. 2009; 24: 87-92
        • Hae-Hyoung L.E.
        • Chung-Jae L.E.
        • Asaoka K.
        Correlation in the mechanical properties of acrylic denture base resins.
        Dent Mater J. 2012; 31: 157-164
        • Bayraktar E.T.
        • Atali P.Y.
        • Korkut B.
        • Kesimli E.G.
        • Tarcin B.
        • Turkmen C.
        Effect of modeling resins on microhardness of resin composites.
        Eur J Dent. 2021; 15: 481-487
        • Tornavoi D.C.
        • Agnelli J.A.M.
        • Lepri C.P.
        • et al.
        Assessment of surface hardness of acrylic resins submitted to accelerated artificial aging.
        Minerva Stomatol. 2012; 61: 282-287
        • Murakami N.
        • Wakabayashi N.
        • Matsushima R.
        • Kishida A.
        • Igarashi Y.
        Effect of high-pressure polymerization on mechanical properties of PMMA denture base resin.
        J Mech Behav Biomed Mater. 2013; 20: 98-104
        • Shulman J.D.
        • Rivera-Hidalgo F.
        • Beach M.M.
        Risk factors associated with denture stomatitis in the United States.
        J Oral Pathol Med. 2005; 34: 340-346
        • Vojdani M.
        • Bagheri R.
        • Khaledi A.A.R.
        Effect of aluminium oxide addition on the flexural strength, surface hardness, and roughness of heat-polymerized acrylic resin.
        JDS. 2012; 7: 238-244
        • Gungor H.
        • Gundogdu M.
        • Yesil Duymus Z.
        Investigation of the effect of different polishing techniques on the surface roughness of denture base and repair materials.
        J Prosthet Dent. 2014; 112: 1271-1277
        • Zissis A.J.
        • Polyzois G.L.
        • Yannikakis S.A.
        • Harrison A.
        Roughness of denture materials: a comparative study.
        Int J Prosthodont. 2000; 13: 136-140
        • Kuhar M.
        • Funduk N.
        Effects of polishing techniques on the surface roughness of acrylic denture base resins.
        J Prosthet Dent. 2005; 93: 76-85
        • Krespi Y.P.
        • Schrime M.G.
        • Kacker A.
        The relationship between oral malodor and volatile sulfur compound-producing bacteria.
        Otolaryngol Head Neck Surg. 2006; 135: 671-676
        • Scannapieco F.A.
        Role of oral bacteria in respiratory infection.
        J Periodontol. 1999; 70: 793-802
        • Sumi Y.
        • Kagami H.
        • Ohtsuka Y.
        • Kakinoki Y.
        • Haruguchi Y.
        • Miyamoto H.
        High correlation between the bacterial species in denture plaque and pharyngeal microflora.
        J Gerodontol. 2003; 20: 84-87
        • Bettencourt A.F.
        • Neves C.B.
        • de Almeida M.S.
        • et al.
        Biodegradation of acrylic based resins: a review.
        Dent Mater. 2010; 26: e171-e180
        • Arima T.
        • Murata H.
        • Hamada T.
        The effects of cross-linking agents on the water sorption and solubility characteristics of denture base resin.
        J Oral Rehabil. 1996; 23: 476-480
        • Dixon D.L.
        • Breeding L.C.
        • Ekstrand K.G.
        Linear dimensional variability of three denture base resins after processing and in water storage.
        J Prosthet Dent. 1992; 68: 196-200
        • Ferracane J.L.
        “Hygroscopic and hydrolytic effects in dental polymer networks”.
        Dent Mater J. 2006; 22: 211-222
        • Göpferich A.
        Mechanisms of polymer degradation and erosion.
        Biomaterials. 1996; 17: 103-114
        • Omata Y.
        • Uno S.
        • Nakaoki Y.
        • et al.
        Staining of hybrid composites with coffee, oolong tea, or red wine.
        Dent Mater J. 2006; 25: 125-131
        • Mushashe A.M.
        • Farıas I.C.
        • Gonzaga C.C.
        • da Cunha L.F.
        • Ferracane J.L.
        • Correr C.M.
        Surface deterioration of indirect restorative materials.
        Braz Dent J. 2020; 31: 264-271
        • Backer A.D.
        • Münchow E.A.
        • Eckert G.J.
        • Hara A.T.
        • Platt J.A.
        • Bottino M.C.
        Effects of simulated gastric juice on CAD-CAM resin composites-morphological and mechanical evaluations.
        J Prosthodont. 2017; 26: 424-443
        • Tseng C.C.
        • Lin P.Y.
        • Kirankumar R.
        • Chuang Z.W.
        • Wu I.H.
        • Hsieh S.
        Surface degradation effects of carbonated soft drink on a resin based dental compound.
        Heliyon. 2021; 7e06400
        • Koda T.
        • Tsuchiya H.
        • Yamauchi M.
        • Ohtani S.
        • Takagi N.
        • Kawano J.
        Leachability of denture-base acrylic resins in artificial saliva.
        Dent Mater J. 1990; 6: 13-16
        • Colombo M.
        • Poggio C.
        • Lasagna A.
        • Chiesa M.
        • Scribante A.
        Vickers micro-hardness of new restorative CAD-CAM dental materials: evaluation and comparison after exposure to acidic drink.
        Materials (Basel). 2019; 12: 1246
        • Lefebvre C.A.
        • Schuster G.S.
        • Marr J.C.
        • Knoernschild K.L.
        The effect of pH on the cytotoxicity of eluates from denture base resins.
        Int J Prosthodont. 1995; 8: 122-128
        • Yap A.
        • Mah M.K.S.
        • Lye C.P.W.
        • Loh P.L.
        Influence of dietary simulating solvents on the hardness of provisional restorative materials.
        Dent Mater. 2004; 20: 370-376
        • Prakkia A.
        • Cillia R.
        • Mondellia R.F.L.
        • Kalachandrab S.
        • Pereiraa J.C.
        Influence of pH environment on polymer based dental material properties.
        J Dent. 2005; 33: 91-98
        • Sulaiman T.A.
        • Abdulmajeed A.A.
        • Shahramian K.
        • et al.
        Impact of gastric acidic challenge on surface topography and optical properties of monolithic zirconia.
        Dent Mater. 2015; 31: 1445-1452
        • Akova T.
        • Ozkomur A.
        • Uysal H.
        Effect of food-simulating liquids on the mechanical properties of provisional restorative materials.
        Dent Mater. 2006; 22: 1130-1134
        • Poskus L.T.
        • Placido E.
        • Cardoso P.E.
        Influence of placement techniques on vickers and knoop hardness of class II composite resin restorations.
        Dent Mater. 2004; 20: 726-732
        • Thompson G.A.
        • Luo Q.
        Contribution of postpolymerization conditioning and storage environments to the mechanical properties of three interim restorative materials.
        J Prosthet Dent. 2014; 112: 638-648
        • Lussi A.
        • Jaeggi T.
        Erosion—diagnosis and risk factors.
        Clin Oral Invest. 2008; 12: 5-13
        • Scheutzel P.
        Etiology of dental erosion—intrinsic factors.
        Eur J Oral Sci. 1996; 104: 178-190
        • Bartlett D.W.
        • Evans D.F.
        • Smith B.G.
        Oral regurgitation after reflux provoking meals: a possible cause of dental erosion?.
        J Oral Rehabil. 1997; 24: 102-108
        • Orr W.C.
        Therapeutic options in the treatment of nighttime gastroesophageal reflux.
        Digestion. 2005; 72: 229-238
        • Orr W.C.
        Sleep issues in gastroesophageal reflux disease: beyond simple heartburn control.
        Rev Gastroenterol Disord. 2003; 3: 22-29
        • Bor S.
        • Sarıtaş Yüksel E.
        How is the gastroesophageal reflux disease prevalence incidence. and frequency of complications (stricture/esophagitis/Barrett’s esophagus/carcinoma) in Turkey compared to other geographical regions globally?.
        Turk J Gastroenterol. 2017; 28: 4-9
        • Moazzez R.
        • Bartlett D.
        Intrinsic causes of erosion.
        in: Lussi A. Ganss C. Erosive tooth wear: from diagnosis to therapy. Karger Medical and scientific publishers, Basel2014: 360-442
        • Holbrook W.P.
        • Furuholm J.
        • Gudmundsson K.
        • Theodors A.
        • Meurman J.H.
        Gastric reflux is a significant causative factor of tooth erosion.
        J Dent Res. 2009; 88: 422-426
        • Bartlett D.W.
        • Coward P.Y.
        Comparison of the erosive potential of gastric juice and a carbonated drink in vitro.
        J Oral Rehabil. 2001; 28: 1045-1047
        • Cengız S.
        • Sarac S.
        • Özcan M.
        Effects of simulated gastric juice on color stability, surface roughness and microhardness of laboratory-processed composites Dent.
        Mater J. 2014; 33: 343-348
        • Matsou E.
        • Vouroutzis N.
        • Kontonasaki E.
        • Paraskevopoulos K.M.
        • Koidis P.
        Investigation of the influence of gastric acid on the surface roughness of ceramic materials of metal-ceramic restorations. An in vitro study.
        Int J Prosthodont. 2011; 24: 26-29
        • Çelebi N.
        • Yüzügüllü B.
        • Canay Ş.
        • Yücel Ü.
        Effect of polymerization methods on the residual monomer level of acrylic resin denture base polymers.
        Polym Adv Technol. 2008; 19: 201-206
        • Alnasser M.
        • Finkelman M.
        • Papathanasiou A.
        • Suzuki M.
        • Ghaffari R.
        • Ali A.
        Effect of acidic pH on surface roughness of esthetic dental materials.
        J Prosthet Dent. 2019; 122: 567
        • Ccahuana V.Z.S.
        • Özcan M.
        • Mesquita A.M.M.
        • Nishioka R.S.
        • Kimpara E.T.
        • Bottino M.A.
        Surface degradation of glass ceramics after exposure to acidulated phosphate fluoride.
        J Appl Oral Sci. 2010; 18: 155-165