Influence of endodontic-treatment and composite-resin-restoration on fracture resistance of maxillary-premolars

Objective: The aim of this study was to evaluate the effect of the endodontic treatment and the restoration with composite resin in the resistance to the fracture of maxillary premolar human with MOD preparation, endodontic treatment and composite resin restoration. Methods: Fifty premolar intact with similar dimensions had been selected, enclosed in polystyrene resin reproducing the periodontal ligament and then divided in 5 different groups (n=10): G1 - intact teeth (control); G2 – MOD preparation; G3 - MOD preparation restored with composite resin Z-250 (3M/ESPE); G4 - MOD preparation and endodontic treatment; G5 - MOD preparation, endodontic and composite resin restoration. The specimes had been submitted the axial load of compression in machine of mechanical assay (EMIC), with speed of 0,5 mm/minute until the fracture. The fracture patterns had been analyzed in 4 levels. Results: The data had been submitted to the analysis of variance and test of Tukey (p<0.05), and then was used factorial analysis (2x2) and test of Tukey. The results had been (Kgf) G1: 83.6±25.4a; G3: 82.1±40.9a; G5: 64.5±18.1ab; G2: 52.7±20.2b and G4: 40.2±14.b. Conclusions: Inside of the limitations of this study, can be concluded that the composite resin obtains to reforce the tooth resistance with MOD preparation. The endodontic treatment teeth restored with composite resin restoration does not refoced fracture resistance.