The Journal of Contemporary Dental Practice

Register      Login



Volume / Issue

Online First

Related articles

VOLUME 23 , ISSUE 2 ( February, 2022 ) > List of Articles


Effect of Hypochlorites on the Compressive Strength and Surface Hardness of Type V Dental Stone: An In Vitro Study

Mansi Nautiyal, KS Jyothi, Seshagiri Muttagi, NT Pallavi, Avita UH D\'Almeida, Chintan P Shah, Harsimran Kaur, Nishtha Singh

Keywords : Compressive strength, Dental stone, Disinfection, Hypochlorite, Surface hardness

Citation Information : Nautiyal M, Jyothi K, Muttagi S, Pallavi N, D\'Almeida AU, Shah CP, Kaur H, Singh N. Effect of Hypochlorites on the Compressive Strength and Surface Hardness of Type V Dental Stone: An In Vitro Study. J Contemp Dent Pract 2022; 23 (2):215-220.

DOI: 10.5005/jp-journals-10024-3248

License: CC BY-NC 4.0

Published Online: 10-06-2022

Copyright Statement:  Copyright © 2022; The Author(s).


Aim: The study aimed to evaluate the compressive strength and surface hardness of a type V dental stone after hypochlorite disinfection. Materials and methods: Two types of specimens were made according to the American Dental Association (ADA) specification no. 25 for each wet compressive strength, dry compressive strength, and surface hardness. The specimens were split into three groups with 30 samples each according to the type of disinfection. All specimens were immersed in their respective disinfecting solutions for 30 minutes at room temperature and after removal, they were left to dry for 24 hours at room temperature. Total five cycles of immersion and drying were followed. A compressive strength test was done using a universal testing machine. Wet compressive strength was tested one hour after the last cycle and dry compressive strength was tested 7 days after the last cycle. Surface hardness was measured after 48 hours using Vickers hardness test. The results were statistically analyzed. Results: There was a statistical difference between the calcium hypochlorite and sodium hypochlorite groups for both dry and wet compressive strength. The mean wet compressive strength of calcium hypochlorite was higher when compared to the sodium hypochlorite group and it was statistically significant (p = 0.042). The results were similar and statistically significant (p = 0.003) for dry compressive strength. When the mean surface hardness of the sodium hypochlorite (As) group was compared to calcium hypochlorite the results were highly significant (p = 0.0001) with the mean surface hardness of the calcium hypochlorite group more than the sodium hypochlorite group. Conclusion: Calcium hypochlorite used as a disinfectant showed better compressive strength and surface hardness when compared to sodium hypochlorite as a disinfectant. Clinical significance: Dental casts poured in the contaminated impressions which might not be disinfected at all or properly. They also come in contact with the prosthesis that might be tried inside the patient's mouth and sent to a lab for corrections without disinfecting the cast causing cross-contamination between patients, dentists, and laboratory personnel. However, immersion disinfection with sodium or calcium hypochlorite might affect important properties of the cast. Any negative effect on the mechanical or physical properties of the cast will affect the final outcome of the prosthesis.

PDF Share
  1. Stern MA, Johnson GH, Toolson LB. An evaluation of dental stones after repeated exposure to spray disinfectants. Part 1: abrasion and compressive strength. J Prosthet Dent 1991;65(5):713–718. DOI: 10.1016/0022-3913(91)90211-e.
  2. Abdelaziz KM, Combe EC, Hodges JS. The effect of disinfectants on the properties of dental gypsum, part 2: surface properties. J Prosthodont 2002;11(4):234–240. DOI: 10.1053/jpro.2002.129049.
  3. Abdelaziz KM, Combe EC, Hodges JS. The effect of disinfectants on the properties of dental gypsum: 1. Mechanical properties. J Prosthodont 2002;11(3):161–167. PMID: 12237796.
  4. Mitchell DL, Hariri NM, Duncanson MG, et al. Quantitative study of bacterial colonization of dental casts. J Prosthet Dent 1997;78(5): 518–521. DOI: 10.1016/s0022-3913(97)70069-6.
  5. Abdullah MA. Surface detail, compressive strength, and dimensional accuracy of gypsum casts after repeated immersion in hypochlorite solution. J Prosthet Dent 2006;95(6):462–468. DOI: 10.1016/j.prosdent.2006.03.019.
  6. Twomey JO, Abdelaziz KM, Combe EC, et al. Calcium hypochlorite as a disinfecting additive for dental stone. J Prosthet Dent 2003;90(3): 282–288. DOI: 10.1016/s0022-3913(03)00412-8.
  7. Sabouhi M, Khodaeian N, Ataei E, et al. The effect of addition of calcium hypochlorite disinfectant on setting expansion and surface hardness of dental stone. J Islam Dent Assoc Iran 2014;26(1): 21–25.
  8. Bass RA, Plummer KD, Anderson EF. The effect of a surface disinfectant on a dental cast. J Prosthet Dent 1992;67(5):723–725. DOI: 10.1016/0022-3913(92)90179-e.
  9. Rudd KD, Morrow RM, Brown CE, et al. Comparison of effects of tap water and slurry water on gypsum casts. J Prosthet Dent 1970;24(5):563–570. DOI: 10.1016/0022-3913(70)90064-8.
  10. Kumar L, Garg AK. In-vitro comparative study of mechanical properties of type V die stone and epoxy resins. Indian J Dent Sci 2014;6(1):64–68. DOI: 10.13140/RG.2.2.14824.72963.
  11. Azer SS, Kerby RE, Knobloch LA. Effect of mixing methods on the physical properties of dental stones. J Dent 2008;36(9):736–744. DOI: 10.1016/j.jdent.2008.05.010.
  12. Kamal A. Some mechanical properties of dental stone specimens after disinfections by 70% hospital spirit. Zanko J Med Sci 2009;13(1):49–54.
  13. Von Fraunhofer JA, Spiers RR. Strength testing of dental stone: a comparison of compressive, tensile, transverse, and shear strength tests. J Biomed Mater Res 1983;17(2):293–299. DOI: 10.1002/jbm.820170208.
  14. Cesero LD, Mota EG, Burnett LH, et al. The influence of postpouring time on the roughness, compressive strength, and diametric tensile strength of dental stone. J Prosthet Dent 2014;112(6):1573–1577. DOI: 10.1016/j.prosdent.2013.07.032.
  15. Silva MAB, Vitti RPV, Consani S, et al. Linear dimensional change, compressive strength and detail reproduction in type IV dental stone dried at room temperature and in a microwave oven. J Appl Oral Sci 2012;20(5):588–593. DOI: 10.1590/S1678-77572012000500016.
  16. Michael J, Khamas AM, Al Azzawi S. Compressive strength and surface roughness of die stone cast after repeated disinfection with sodium hypochlorite solution. J Bagh Coll Dentistry 2010;22(3):27–33.
  17. Villani FA, Aiuto R, Paglia L, et al. COVID-19 and dentistry: prevention in dental practice, a literature review. Int J Environ Res Public Health 2020;17(12):4609. DOI: 10.3390/ijerph17124609.
  18. Onizuka T, Kamimura N, Kajiwara H, et al. Influence of boiling water treatment on surface roughness and surface microstructure of set gypsum (dental stone). Dent Mater J 1995;14(2):245–255. DOI: 10.4012/dmj.14.245.
  19. Sudhakar A, Srivatsa G, Shetty R, et al. Evaluation of the various drying methods on surface hardness of type IV dental stone. J Int Oral Health 2015;7(6):103–106. PMID: 26124610.
  20. Meghashri K, Kumar P, Prasad DK, et al. Evaluation and comparison of high level microwave oven disinfection with chemical disinfection of dental gypsum casts. J Int Oral Health 2014;6(3):56–60. PMID: 25083033.
  21. Sarma AC, Neiman R. A study on the effect of disinfectant chemicals on physical properties of die stone. Quintessence Int 1990;21(1):53–59. PMID: 2115681.
  22. ADA Council on Scientific Affairs and ADA Council on Dental Practice. Infection control recommendations for the dental office and the dental laboratory. J Am Dent Assoc 1988;116(2):241–248. DOI: 10.14219/jada.archive.1988.0341.
  23. ADA Council on Scientific Affairs and ADA Council on Dental Practice. Infection control recommendations for the dental office and the dental laboratory. J Am Dent Assoc 1996;127(5):672–680. DOI: 10.14219/jada.archive.1996.0280.
  24. Kampf G, Todt D, Pfaender S, et al. Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents. J Hosp Infect 2020;104(3):246–251. DOI: 10.1016/j.jhin.2020.01.022.
  25. Anusavice KJ, Shen C, Rawls HR. Phillip's science of dental materials. 12th ed. India: Elsevier India Private Limited; 2013.
  26. Sakaguchi RL, Powers JM. Craig's restorative dental materials. 13th ed. India: Elsevier India Private Limited; 2012.
  27. Breault LG, Paul JR, Hondrum SO, et al. Die stone disinfection: incorporation of sodium hypochlorite. J Prosthodont 1998;7(1):13–16. DOI: 10.1111/j.1532-849x.1998.tb00170.x.
  28. Coombe EC. Notes on dental materials. 6th ed. London: Churchill Livingstone; 1992.
  29. Azimi G, Papangelakis VG, Dutrizac JE. Modelling of calcium sulphate solubility in concentrated multi-component sulphate solutions. Fluid Ph Equilibria 2007;260(2):300–315. DOI: 10.1016/j.fluid.2007.07.069.
  30. National Center for Biotechnology Information. PubChem Compound Database; CID=24504. Available from:
PDF Share
PDF Share

© Jaypee Brothers Medical Publishers (P) LTD.