Effect of thermal cycling on microleakage between hard chairside relines and denture base acrylic resins.
OBJECTIVE
Microleakage is a pre-stage of debonding between hard chairside relines and denture base acrylic resins. Therefore, it is important to assess them with regard to the longevity of the relined denture. This study investigated the effect of thermal cycling on the microleakage at the interface of three hard chairside reline resins and three denture base resins.


METHODS
Rectangular bars (12 mm × 3 mm × 3 mm) of Lucitone 550, Acron MC and QC 20 were made and relined with Kooliner, Tokuyama Rebase Fast II and Ufi Gel Hard, Lucitone 550, Acron MC and QC 20 resins. Specimens were divided into one control and two test groups (n=10). In specimens of the control group, the microleakage was performed after the reline procedure. In Test Group 1, the specimens were stored for 24 h in distilled water at room temperature and in Test Group 2; the specimens were thermal cycled from 5 to 55°C for 5000 cycles with a 30-s dwell time. Subsequently, all specimens were immersed in 50% silver nitrate solutions for 24h. All specimens were sectioned longitudinally into three fractions and the lateral sections were examined (n=20). Silver nitrate stain penetration was examined under a stereoscopic lens with ×30 magnification, and the images were captured. Leica Qwin image analysis software was used to determine microleakage at the interface of the materials. Data were analysed using the Kruskal-Wallis test at a 95% level of significance.


RESULTS
For all cycles, there were no statistically significant differences between thermal cycled and non-thermal cycled groups (p>0.05).


CONCLUSIONS
It can be concluded that thermal cycling had no effect on the microleakage.
Giampaolo
Eunice Teresinha
ET
Department of Dental Materials and Prosthodontics, Araraquara Dental School, Sao Paulo State University, UNESP, Araraquara, Sao Paulo, Brazil. eunice@foar.unesp.br
Jorge
Janaina Habib
JH
Machado
Ana Lúcia
AL
Pavarina
Ana Cláudia
AC
Vergani
Carlos Eduardo
CE
D000180:Acrylic Resins / Q000737:chemistry*; D003763:Dental Leakage / Q000145:classification*; D003764:Dental Materials / Q000737:chemistry*; D003819:Denture Bases; D003822:Denture Liners; D003823:Denture Rebasing; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D012826:Silicone Elastomers / Q000737:chemistry; D016622:Silver Staining; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
D000180:Acrylic Resins; D003764:Dental Materials; D008689:Methacrylates; C488492:QC 20 (denture base resin); D012826:Silicone Elastomers; C483158:Ufi gel; C514244:tokuyama rebase fast II; D014867:Water; C103363:kooliner; C075051:Acron MC; C040291:Lucitone