Microleakage of caries and healthy human teeth restored with GI

Purpose: To examine the ability of conventional glass ionomers (CGI) and resin-modified glass ionomers (RGI) to prevent water induced microleakage in caries affected teeth restored following atraumatic restorative treatment (ART) and sound teeth with cavity preparations class I, II and III restored over 24 hours and thermocycled.

Methods: 40 extracted decayed molars and 40 extracted sound molars were divided in 4 groups: Two CGI; Photac Fil Quick (Ph, GC-America) and Ketac Nano (KN, 3M-ESPE), and two RGI; Ketac Molar Quick (KMQ, 3M-ESPE), Tokuso Ionomer (Tk, Tokuyama). Restored teeth were divided in two microleakage methods one was sectioned into 0.9 mm thick slabs and the other was group was not sectioned. Specimens were divided in two groups one was stored in Hank's solution for 24 hours and the other was thermocycled 500 times between water baths held at 5◦, 37◦ and 55◦ C with a dwell time of 5s in extreme temp. and 20s at 37°C. After storage, a silver tracer was used to reveal micrometer-sized water filled spaces and changes in the CGI and RGI/decayed and sound interfaces. Analysis of the interfaces was performed under SEM. ANOVA and Fisher's PLSD (P<0.05) for glass ionomers; caries and sound; and storage conditions were calculated.

Results: The two RGI showed less silver uptake compared to the two CGI.  Caries affected specimens showed more silver uptake compared to sound teeth. 24 hours stored teeth showed less silver uptake compared to thermocycle specimens.

Conclusion: Different levels of water-induced microleakage were observed in this study but none of the CGI and RGI showed the ability to prevented microleakage.

Acknowledgments: NIH T32 DE07306, materials provided by 3M-ESPE, and Tokuyama Dental Corporation