Marginal microleakage around class V cavities restored with glass ceramic inserts of different coefficients of thermal expansion.
OBJECTIVE
Evaluate microleakage around Class V resin restorations restored with glass ceramic inserts of different coefficients of thermal expansion.


METHODS
Sixty non-carious extracted human premolars (patient age range 12-20 years) were randomly assigned to three groups. Standard Class V preparations were cut in the buccal surface using customized Cerana burs, size 3. Glass ceramic inserts from two manufacturers (Cerana and Beta-Quartz) were used to restore the cavities, and were luted with a hybrid, high-viscous composite (Tetric Ceram) and a bonding agent (Excite). A control group, without inserts, was bulk-filled with a hybrid, high-viscous composite (Tetric Ceram). In accordance with American Dental Association (ADA) guidelines, half the preparation was in enamel and half in dentine/cementum, and had a mesio-distal width of 3 mm, an occluso-gingival height of 3 mm, and a depth of 2 mm. All margins had butt joints. The teeth were thermocycled 4000 times between water baths held at 5 degrees C and 55 degrees C, and the specimens prepared and examined for microleakage using 2.0% Procion Red dye, buffered at pH 7 as a marker.


RESULTS
Microleakage was significantly less around cavities restored with Cerana glass ceramic inserts than around cavities restored with Beta Quartz glass ceramic inserts or the control cavities at both the occlusal and gingival margins, p = 0.003 and p = 0.014, respectively. Comparisons of both occlusal and gingival margins within both test groups and the control group showed there was significantly less microleakage at the enamel-resin interface than at the dentine-resin interface (p < 0.05 in all cases).


CONCLUSIONS
The results strongly suggest that restorations restored with Cerana glass ceramic inserts, which have a coefficient of therml expansion approximating that of enamel, result in a decrease in marginal microleakage compared to Beta Quartz glass ceramic inserts and Tetric Ceram resin-based composite material.
Edinburgh Postgraduate Dental Institute, The University of Edinburgh, United Kingdom.
Chuei Luan
CL
Tan
Ario
A
Santini
D000180:Acrylic Resins / Q000737:chemistry; D000293:Adolescent; D000328:Adult; D001641:Bicuspid; D002516:Ceramics / Q000737:chemistry*; D002648:Child; D003188:Composite Resins / Q000737:chemistry*; D003731:Dental Caries / Q000628:therapy; D003763:Dental Leakage; D005898:Glass / Q000737:chemistry*; D006801:Humans; D011140:Polyurethanes / Q000737:chemistry; D011791:Quartz / Q000737:chemistry*; D018709:Statistics, Nonparametric
D000180:Acrylic Resins; C088834:Beta-Quartz glass-ceramic; C113675:Cerana; C029012:Composite Dental Resin; D003188:Composite Resins; D011140:Polyurethanes; C121818:Tetric ceram; D011791:Quartz; C023506:Glass ceramics