The comparison of surface hardness, water sorption and staining resistance between thermoplastic nylon and heat-cured acrylic resin.
Comparison of nylon and heat-cured acrylic resin
Aim: To evaluate and compare the surface hardness, water sorption and staining resistance of conventional heat cure and nylon denture base materials.
Materials and Methods: A total of 120 specimens, which comprises thirty from each denture base materials (Acralyn-H, DPI, Valplast and Flexident), were fabricated by investing metal specimen analogues of dimension 65x10x2.5mm strips for hardness, 50x0.5mm discs for water sorption and 20x1mm discs for staining resistance according to ADA specification no.12. The surface hardness was evaluated using Shore D Durometer. Water sorption was tested by the differences in the weight of the specimens by desiccating in calcium chloride and immersing in water for one week. The specimens were placed in a staining solution of 3% tartrazine for 7days. Staining resistance was evaluated by the optical density of the extraction solvent (ethanol) using spectrophotometer.
Results: Heat cure acrylic denture base materials demonstrated more surface hardness compared to nylon based denture materials. Tukey’s HSD showed significant differences (p<0.05) in the hardness of heat cure and nylon denture base materials. The water sorption values of Acralyn-H, DPI and Valplast were comparable and showed a statistically significant difference (p<0.05) in the water sorption with Flexident. In staining resistance test, Valplast demonstrated more optical density whereas the optical densities of the others materials were comparable. Valplast materials displayed significant differences (p<0.05) in staining resistance with heat cure denture base materials.
Conclusions: Both the heat cure denture base materials exhibited greatest surface hardness compared to the flexible denture base materials. Flexident displayed the lowest water sorption and Valplast had the least staining resistance.
Polymethylmethacrylate, nylon denture base materials, staining resistance., urface hardness, water sorption,
2. Alla RK, Swamy KNR, Vyas R, Konakanchi A, Conventional & contemporary polymers for the fabrication of denture prosthesis: Part I: Overview of Composition, Chemistry and Properties, Int J Appl Dent Sci, 2015:1(4):82-9.
3. Parvizi A, Lindquist T, Schneider R, Williamson D, Boyer D, Dawson DV. Comparison of the dimensional accuracy of injection molded denture base materials to that of conventional pressure pack acrylic resins. J Prosthodont. 2004; 13:83-89.
4. Alla RK, Suresh Sajjan MC, Ramaraju AV, Ginjupalli K, Upadhya N. Influence of Fiber reinforcement on the properties of denture base resins, J Biomater Nanobiotech, 2013; 4(1): 91-97.
5. Alla RK, Denture Base Resins in Dental Materials Science,1stedition, Jaypee Medical Publishers Pvt limited, New Delhi, India, 2013, 248-284.
6. Alla RK, Swamy KNR, Ritu Vyas, Konakanchi A, Vineeth G, Gadde P, Influence of Silver nanoparticles incorporation on Flexural strength of Heat-cure acrylic denture base resin materials, ARRB 2017; 17(4): 1-8.
7. Musanje L, Dawell BW. Aspects of water sorption from air, water and artificial saliva in resin composite restorative materials. Dental Mater J.2003; 19:414-422.
8. Philips RW. Science of dental materials. 9th ed. WB.Saunders; 1991 p.172-4.
9. Vojdani M, Giti R, Polyamide as a Denture Base Material: A literature Review, J Dent Shiraz Univ Med Sci., 2015; 16(1Suppl): 1-9.
10. Foo SH, Lindquist TJ, Aquilino SA, Schneider RL, Williamson DL. Effect of polyaramid fiber reinforcement on the strength of 3 denture base polymethyl methacrylate resins. J Prosthodont. 2001; 10:148-153.
11. Aruna Kumari S, Narendra R, Sesha Reddy P, Sashideepth Reddy, Uma KC, Rama Krishna Alla, Anusha Konakanchi. Evaluation and Comparison of Flexural Strength of Conventional Heat Cured Denture Base Polymers with Nylon Denture Base Polymers: An In Vitro Study, Trends Biomater. Artif. Organs, 2017; 31(1): 29-32.
12. Alla RK, Raghavendra Swamy KN, Ritu Vyas, Prakash Tiruveedula NB, Alluri Murali Krishnam Raju, Physical and Mechanical Properties of Heat activated Acrylic Denture Base Resin Materials, Research J. Pharm. and Tech. 2018; 11(6): 2258-2262.
13. Craig RG. Restorative dental materials, 10th ed. St Louis, MO, USA: Mosby Co; 1997:73.
14. Mieszko Wieckiewicz,1 Volker Opitz,2 Gert Richter,2 and Klaus W. Boening2. Physical Properties of Polyamide-12 versus PMMA Denture Base Material. BioMed Research International Volume 2014, Article ID 150298, 8 pages http://dx.doi.org/10.1155/2014/150298.
15. Utami M, Febrida R, Djustiana N. The comparison of surface hardness between thermoplastic nylon resin and heat-cured acrylic resin. Padjadjaran Journal of Dentistry 2009;21(3):200-203.
16. Malacarne J, Carvalho RM, de Goes MF, Svizero N, PashleyDH, Tay FR, et al. Water sorption/solubility of dental adhesive resins. Dent Mater 22; 2006 :973‑80.
17. Dentistry- Denture base polymers, ISO 1567, International Standard Organization, 1999.
18. Arundathi R, Patil NP. An investigation into the transverse strength and impact strength of a new indigenous high-impact denture base resin, DPI tuff and its comparison with most commonly used two denture base resins. J Ind Prosthodon Soc. 2006;6(3):133-138.
19. National Center for Biotechnology Information. PubChem Database. Tartrazine, CID=164825, https://pubchem.ncbi.nlm.nih.gov/compound/Tartrazine (accessed on June 24, 2020).
20. Marcelo Coelho Goiato, Daniela Micheline dos Santos, Marcela Filie Haddad, Aldiéris Alves Pesqueira. Effect of accelerated aging on the microhardness and color stability of flexible resins for dentures. Braz Oral Res. 2010;24(1):114-9.
21. Anil N, Hekimoglu C, Sahin S. Color stability of heat-polymerized and autopolymerized soft denture liners. J Prosthet Dent. 1999 Apr;81(4):481-4.
22. Rosentritt M, Esch J, Behr M, Leibrock A, Handel G. In vivo color stability of resin composite veneers and acrylic resin teeth in removable partial dentures. Quintessence Int. 1998 Aug;29(8):517-22.