Efetividade da irradiação por microondas na desinfecção de resinas reembasadoras rígidas e resina acrílica para base de prótese
Effectiveness of microwave irradiation on disinfection of hard chairside reline resins and denture base resin
Neppelenbroek, K.H.; Mima, E.G.O.; Spolidorio, D.M.P.; Giampaolo, E.T.; Vergani, C.E.; Pavarina, A.C.
Rev. odontol. UNESP, vol.35, n4, p.305-311, 2006
Resumo
Este estudo avaliou a efetividade da irradiação por microondas na desinfecção de duas resinas acrílicas autopolimerizáveis rígidas para reembasamento imediato (Duraliner II-D e New Truliner-N) e uma resina acrílica termopolimerizável para base de prótese (Lucitone 550-L). Os corpos-de-prova (n = 276) foram confeccionados e esterilizados por óxido de etileno. Então, os corpos-de-prova foram individualmente inoculados com 107 cfu.mL-1 de cada microorganismo patogênico testado (C.albicans-Ca, S. aureus-Sa, B. subtilis-Bs e P. aeruginosa-Pa). Após 48 horas de incubação a 37 °C, 40 corpos-de-prova de cada material foram imersos em 200 mL de água e irradiados a 650 W por 6 minutos e 40 corpos-de-prova não foram irradiados (controle positivo). Da suspensão resultante da agitação dos corpos-de-prova, foram obtidas diluições seriadas de 10-3 a 10-6, que foram semeadas (25 μL) em duplicata nos meios de cultura seletivos para cada microrganismo. Após o período de incubação, os números de ufc.mL-1 referentes às colônias viáveis foram transformados em logaritmo na base 10 e submetidos ao teste de Kruskal-Wallis ( α = 0,05). Os corpos-de-prova irradiados foram incubados a 37 °C por 7 dias. Doze corpos-de-prova de cada material foram preparados para análise em MEV e observados em aumentos de 2.000 e 3.500x. A energia de microondas esterilizou os materiais testados após a irradiação e 7 dias de incubação. A análise em MEV indicou alteração na colônia e na morfologia dos microrganismos após irradiação. Para o grupo controle, foi possível verificar que, estatisticamente, os números de ufc.mL-1 dos microrganismos testados se apresentaram da seguinte forma: Pa = Sa > Ca = Bs para as resinas D e N e Sa > Pa = Ca > Bs para a resina L. A irradiação por microondas por 6 minutos a 650 W foi efetiva ao esterilizar os três materiais avaliados após 48 horas e 7 dias de incubação a 37 °C.
Palavras-chave
Reembasadores de dentadura, resinas acrílicas, desinfecção, microondas,
controle de infecção.
Abstract
This study assessed the effectiveness of microwave irradiation on disinfection of two hard chairside reline resin (Duraliner II-D e New Truliner-N) and one denture base resin (Lucitone 550-L). Specimens (n = 240) were produced and subjected to ethylene oxide sterilization. Then, specimens were individually inoculated with 107 cfu.mL-1 of one tested microorganism (C albicans-Ca, S. aureus-Sa, B. subtilis-Bs, and P. aeruginosa-Pa). After 48 hours at 37 °C, 40 specimens of each material were immersed in 200 mL of water and microwaved at 650 W for 6 minutes and 40 specimens were not irradiated (positive control). Dilutions of 10-3 to 10-6 from the suspension of vortexed specimens were plated (25 μL) in duplicate on plates of selective media appropriate for each organism. All plates were incubated at 37 °C for 48 hours and colonies were counted. Irradiated specimens were incubated at 37 °C for 7 days. Log cfu.mL-1 values were calculated and statistically analyzed by the Kruskal-Wallis test (α = 0.05). All irradiated specimens showed sterilization after microwave irradiation and 7 days of incubation. Twelve specimens of each material were prepared for SEM analysis and examined at 2,000 and 3,500x magnification. SEM examination indicated alteration in cell and colony morphology after irradiation. The sequence in cfu.mL-1 values for control specimens, arranged in terms of statistical significance was: Pa = Sa > Ca = Bs for N and D resins, and Sa > Pa = Ca > Bs, for L resin. Microwave irradiation for 6 minutes at 650 W was effective for sterilization of the 3 tested materials.
Keywords
Denture liners, acrylic resins, disinfection, microwave, infection control
References
1. McGivney G, Castleberry D. Reembasamento da prótese parcial removível. In: McGivney G, Castleberry D. Prótese parcial removível de McCracken. São Paulo: Artes Médicas; 1994. p.288-92.
2. Arima T, Murata H, Hamada T. Properties of highly cross-linked autopolymerizing reline acrylic resins. J Prosthet Dent. 1995;73:55-9.
3. Bunch J, Johnson GH, Brudvik JS. Evaluation of hard direct reline resins. J Prosthet Dent. 1987;57:512-9.
4. Chau VB, Saunders TR, Pimsler M, Elfring DR. Indepth disinfection of acrylic resins. J Prosthet Dent. 1995;74:309-13.
5. Powell GL, Runnells RD, Saxon BA, Whisenant BK. The presence and identification of organisms transmitted to dental laboratories. J Prosthet Dent. 1990;64:235-7.
6. Connor C. Cross-contamination control in prosthodontic practice. Int J Prosthodont. 1991;4:337-44.
7. American Dental Association. 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;127:672‑80.
8. Carrol DE, Lopez A. Lethality of radio-frequency energy upon microorganisms in liquid, buffered, and alcoholic food systems. J Food Sci. 1969;34:320-4.
9. Culkin KA, Fung DYC. Destruction of Escherichia coli and Salmonella typhimurium in microwave-cooked soups. J Milk Food Technol. 1975;38:8-15.
10. Hume WR, Makinson OF. Sterilizing dental instruments: evaluation of lubricating oils and microwave irradiation. Oper Dent. 1978;3:93-6.
11. Hiti K, Walochnik J, Faschinger C, Haller-Schober EM, Aspock H. Microwave treatment of contact lens cases contaminated with acanthamoeba. Cornea. 2001;20:467‑70.
12. Rohrer MD, Terry MA, Bulard RA, Graves DC, Taylor EM. Microwave sterilization of hydrophilic contact lenses. Am J Ophthalmol. 1986;15:49-57.
13. Ikawa JY, Rossen JS. Reducing bacteria in household sponges. J Environ Health. 1999;62:1-5.
14. Friedrich EG Jr, Phillips LE. Microwave sterilization of Candida on underwear fabric. A preliminary report. J Reprod Med. 1988;33:421-2.
15. Border BG, Rice-Spearman L. Microwaves in the laboratory: effective decontamination. Clin Lab Sci. 1999;12:156-60.
16. Fitzpatrick JA, Kwao-Paul J, Massey J. Sterilization of bacteria by means of microwave heating. J Clin Eng. 1978;3:44-7.
17. Najdovski L, Dragas AZ, Kotnik V. The killing activity of microwaves on some non-sporogenic and sporogenic medically important bacterial strains. J Hosp Infect. 1991;19:239-47.
18. Watanabe K, Kakita Y, Kashige N, Miake F, Tsukiji T. Effect of ionic strength on the inactivation of micro-organisms by microwave irradiation. Lett Appl Microbiol. 2000;31:52-6.
19. Neppelenbroek KH, Pavarina AC, Spolidorio DM, Vergani CE, Mima EG, Machado AL. Effectiveness of microwave sterilization on three hard chairside reline resins. Int J Prosthodont. 2003;16:616-20.
20. Cole EC, Robison R. Test methodology for evaluation of germicides. In: Ascenzi JM. Handbook of disinfectants and antiseptics. New York: Marcel Dekker;
1996. p.1‑13.
21. Dixon DL, Breeding LC, Faler TA. Microwave disinfection of denture base materials colonized with Candida albicans. J Prosthet Dent. 1999;81:207-14.
22. Yeo CB, Watson IA, Stewart-Tull DE, Koh VH. Heat transfer analysis of staphylococcus aureus on stainless steel with microwave radiation. J Appl Microbiol. 1999;87:396-401.
23. Verran J, Maryan CJ. Retention of Candida albicans on acrylic resin and silicone of different surface topography. J Prosthet Dent. 1997;77:535-9.
24. Hauser PM, Errington J. Characterization of cell cycle events during the onset of sporulation in Bacillus subtilis. J Bacteriol. 1995;177:3923-31.
25. Zissis AJ, Polyzois GL, Yannikakis SA, Harrison A. Roughness of denture materials: a comparative study. Int J Prosthodont. 2000;13:136-40.
26. Radford DR, Challacombe SJ, Walter JD. Adherence of phenotypically switched Candida albicans to denture base materials. Int J Prosthodont. 1998;11:75-81.
27. 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.
28. Webb BC, Thomas CJ, Harty DW, Willcox MD. Effectiveness of two methods of denture sterilization. J Oral Rehabil. 1998;25:416-23.
29. Rosaspina S, Salvatorelli G, Anzanel D, Bovolenta R. Effect of microwave radiation on Candida albicans. Microbios. 1994;78(314):55-9.
30. Pavarina AC, Neppelenbroek KH, Guinesi AS, Vergani CE, Machado AL, Giampaolo ET. Effect of microwave disinfection on the flexural strength of hard chairside reline resins. J Dent. 2005;33:741-8.
31. Novais PMR. Análise da porosidade superficial em materiais reembasadores rígidos. Efeitos de sucessivas irradiações por energia de microondas [Tese de Doutorado]. Araraquara: Faculdade de Odontologia da UNESP; 2005.
32. Campanha NH, Pavarina AC, Vergani CE, Machado AL. Effect of microwave sterilization and water storage on the Vickers hardness of acrylic resin denture teeth. J Prosthet Dent. 2005;93:483-7.
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