:: Volume 25, Issue 4 (10-2013) ::
J Iran Dent Assoc 2013, 25(4): 242-248 Back to browse issues page
The Effect of Microwave Disinfection on Dimensional Stability and Flexural Strength of Acrylic Resins
Omid Tavakkol1, Ehsan Farjood2, Venos Mortazavi3, Mahroo Vojdani *4
1- Prosthodontist
2- Postgraduate Student, Department of Prosthodontic, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran
3- Specialist in Operative Dentistry
4- Professor, Biomaterial Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran , vojdanim@yahoo.com
Abstract:   (8030 Views)

  Background and Aim: Several studies have evaluated the effect of microwave radiation on physical properties of acrylic resins. However, due to the recent introduction of heat-cure and cold-cure acrylic resins into the dental market and rapid popularity of cold-cure resins with less distortion in denture base, the present study sought to assess the effect of microwave disinfection on dimensional stability and flexural strength of two recently introduced heat-cure (Ivoclar) and cold-cure (FuturaGen) acrylic resins .

  Materials and Methods : In this laboratory study, acrylic models were fabricated of an edentulous maxillary model using Ivoclar and FuturaGen acrylic resins. Three reference points were marked on the model: two in the back and one in the front of the edentulous arch. These reference points were used for the measurement of dimensional stability in the anteroposterior and cross-arch dimensions. Ten specimens of each acrylic resin were not disinfected. Ten samples were subjected to two 3 min cycles of microwave disinfection with 600 watt power. Distances between the reference points were measured by a Profile Projector. To evaluate flexural strength, a metal mould measuring 64x10x3.3 mm was used for the fabrication of resin specimens. Similar to what was done for dimensional stability testing, 10 specimens of each acrylic resin were not disinfected and 10 other samples were subjected to 3-point bending test after disinfection. Data were compared and statistically analyzed using Mann-Whitney U test .

  Results: The mean difference in anteroposterior and cross-arch dimensions revealed that two cycles of microwave disinfection of Ivoclar and FuturaGen acrylic resins did not have a significant effect on their dimensional stability (P>0.017). The mean and standard deviation of the flexural strength of FuturaGen acrylic resin before and after disinfection was 76.86±16.80 and 70.18±8.48, respectively. These values for Ivoclar acrylic resin were 85.92±12.23 and 81.91±6.59, respectively. Two cycles of disinfection with microwave did not cause a significant effect on flexural strength of the two understudy acrylic resins (P>0.05) .

  Conclusion: Two cycles of microwave disinfection had no negative effect on dimensional stability or flexural strength of FuturaGen and Ivoclar acrylic resins .

Keywords: Acrylic resin, disinfection, microwave
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Type of Study: Orginal | Subject: Porosthodontics
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