Disinfection procedures: Their efficacy and effect on dimensional accuracy and surface quality of an irreversible hydrocolloid impression material

Abstract

Please cite this article as: Rentzia A, Coleman DC, O'Donnell MJ, Dowling AH, O'Sullivan M, Disinfection procedures: their efficacy and effect on dimensional accuracy and surface quality of an irreversible hydrocolloid impression material, Journal of Dentistry (2010Dentistry ( ), doi:10.1016Dentistry ( /j.jdent.2010 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. controls. Dimensional accuracy measurements were completed between fixed points using a travelling microscope under low angle illumination at a magnification of X3.Surface quality changes of "smooth" and "rough" areas on the cast were evaluated by means of optical profilometry. The efficacy of the disinfection procedures againstPseudomonas aeruginosa was evaluated by determining the number of colony forming units (cfu) recovered after disinfection of alginate discs inoculated with 1x10 6 cfu for defined intervals. Results:The dimensional accuracy of the gypsum casts was not significantly affected by the disinfection protocols. Neither disinfectant solution nor immersion time had an effect on the surface roughness of the "smooth" area on the cast, however, a significant increase in surface roughness was observed with increasing immersion time for the "rough" surface. Complete elimination of viable Pseudomonas aeruginosa cells from alginate discs was obtained after 30 and 120 s immersion in Cidex OPA ® and NaOCl, respectively. Conclusions:Immersion of irreversible hydrocolloid impressions in Cidex OPA ® for 30 s was proved to be the most effective disinfection procedure.

Effects of immersion disinfection of agar-alginate combined impressions on the surface properties of stone casts

“…As agar impression materials appear to require an immersion time of less than 10 min, agar-alginate combined impressions might have a similar requirement. The germicidal effects of short-term immersion of hydrocolloid impression materials in disinfectant solutions have been reported 12,15,16) . Therefore the aim of this study was to examine the effects of immersion of agar-alginate combined impressions in disinfectant solutions for 1, 3, 5 and 10 min on the surface properties of the resulting stone casts.…”

“…It has been reported that immersion of alginate impressions in 0.5% sodium hypochlorite solution for 1 min inactivates viruses 15) , and that immersion of alginate impressions in 0.6% sodium hypochlorite solution for two min is sufficient to prevent bacterial growth 16) . Complete elimination of Pseudomonas aeruginosa colonies from alginate discs after immersion for 30 s in 0.55% ortho-phthalaldehyde solution or 120 s in 0.5% sodium hypochlorite solution has been reported 12) . Therefore, as a new infection control method for dental treatment, it may be necessary to examine the effects of short-term immersion of agar-alginate combined impressions in disinfectant solutions on the resulting stone casts.…”

“…However, the effects of immersion in orthophthalaldehyde solution in place of glutaraldehyde, which is toxic, have not been examined, and so far such effects have been reported only for alginate impressions 12) . It has been reported that the surface roughness of stone casts produced from agar-alginate combined impressions immersed in sodium hypochlorite solution for 10-15 min was greater than that without immersion for some products 10,11) , whereas the effects of short-term immersion have not been investigated.…”

Precisão dimensional de moldes de hidrocoloide irreversível manipulado com solução de clorexidina

“…Alguns métodos têm sido propostos para descontaminar os modelos de gesso, tais como imersão em solução de hipoclorito de sódio a 0,525% 11 ou incorporação de soluções desinfetantes no ato da mistura do gesso 25 . No entanto, esses métodos têm resultado em alterações nas propriedades dos gessos, tais como menor resistência à compressão e menor dureza superficial [26][27][28] .…”

Does the contact time of alginate with plaster cast influence its properties?

“…This study has elucidated some of the consequences of increasing the time of contact between alginate and gypsum, however, this factor must be tested under other conditions to simulate the clinical routine, for example, performing disinfection of the casts, 18,19 as well as using 100% humidity while the plaster undergoes setting to avoid alginate syneresis. Further research is also suggested using other times of contact between alginate and plaster, longer than 1 hour, but shorter than 12 hours.…”