Influence of resin cements on cuspal deflection and fracture load of endodontically-treated teeth restored with composite inlays.
OBJECTIVE
To evaluate the influence of resin cements on cuspal deflection, fracture load and failure mode of endodontically-treated teeth restored with composite resin inlays.


METHODS
Forty maxillary premolars were randomly divided into four groups: G1 (sound teeth, control), G2 (RelyX ARC), G3 (RelyX Unicem) and G4 (Maxcem Elite). The teeth from groups 2, 3 and 4 received mesial-occlusal-distal preparations and endodontic treatments. Impressions were taken with vinyl polysiloxane and poured using type IV die stone. Inlays with Z250 composite resin were built over each cast and luted with the resin cements. A 200-N load was applied on the occlusal surface and the cuspal deflection was measured using a micrometer. The specimens were then subjected to an axial load until failure occurred. The resulting failure mode was analyzed.


RESULTS
The means for cuspal deflection (μm) and fracture load (N) followed by the same letter represent no statistically significant difference based on ANOVA and Tukey's test (p < 0.05). Cuspal deflection: G1 = 4.7 (± 1.7)(a), G2 = 12.0 (± 8.9)(a), G3 = 39.0 (± 27.0)(b) and G4 = 56.8 (± 18.2)(b). Fracture load: G1 = 1982 (± 893)(a), G2 = 690.9 (± 225.5)(b), G3 = 679 (± 193.6)(b) and G4 = 465.5 (± 121.6)(b). G1 presented cusp fractures only at the cement-enamel junction (CEJ). There was a high frequency of cusp fractures below the CEJ in G2, G3 and G4.


CONCLUSIONS
Composite resin inlays luted with resin cements do not recover the strength of sound teeth. However, teeth restored with composite resin inlays and luted with RelyX ARC can withstand mechanical fatigue longer before failure occurs than those luted with RelyX Unicem and Maxcem Elite.
Department of Restorative Dentistry, Pontifical Catholic University of Rio Grande do Sul, Brazil.
Rhuy Jacob Cezarotto
RJ
Dall Agnol
Paula Cristine
PC
Ghiggi
Maria Paula Gandolfi
MP
Paranhos
Gilberto Antonio
GA
Borges
Luiz Henrique
LH
Burnett
Ana Maria
AM
Spohr
D000704:Analysis of Variance; D003481:Cuspid / Q000502:physiology*; D003799:Dental Stress Analysis; D004708:Endodontics; D006801:Humans; D019279:Resin Cements
D019279:Resin Cements