title: [Fracture resistance of endodontically treated mandibular premolars restored with e.max press all-ceramic onlays and metal crowns].
abstract: OBJECTIVE
  To compare the fracture resistance of endodontically treated mandibular premolars restored with e.max press all-ceramic onlays and metal crowns.
  
  
  METHODS
  Forty-five endodontically treated mandibular premolars were randomly divided into 3 groups. Group A were filled with resin as control. Specimens of group B and C were instrumented and prepared for two-wall cavities and restored with metal crowns and ceramic onlays respectively. The specimens were thermocycled, exposed to cyclic loading, and submitted to the static fracture resistance test. Fracture loads and mode of failure were evaluated. The data was analyzed with SPSS13.0 software package.
  
  
  RESULTS
  Samples in 2 experimental groups exhibited higher fracture load values than that of the control group (P<0.05). Group C showed higher fracture load values and more favourable fracture patterns compared with group B (P<0.05).
  
  
  CONCLUSIONS
  Endodontically treated mandibular molars restored with indirect onlays provide significantly increased fracture resistance and favourable fracture patterns.
authors.affiliation: Department of VIP Consultants, Ningbo Dental Hospital. Ningbo 315000, Zhejiang Province, China.E-mail:pipioppo@163.com.
authors.forename: Yu-shan
authors.initials: YS
authors.lastname: Wang
authors.forename: Yi-li
authors.initials: YL
authors.lastname: Zhou
mesh_terms: D001641:Bicuspid; D002516:Ceramics; D003442:Crowns; D006801:Humans; D007284:Inlays; D008670:Metals; D008963:Molar; D014082:Tooth Fractures
chemical_list: D008670:Metals