title: Fracture resistance of the buccal cusps of root filled maxillary premolar teeth restored with various techniques.
abstract: OBJECTIVE
  To compare the cusp fracture resistance of teeth restored with composite resins and two post systems.
  
  
  METHODS
  Eighty extracted single-rooted human maxillary premolars were randomly assigned to eight groups (n = 10). Group 1 (control) did not receive any preparation. From groups 2 to 8, the teeth were root filled and mesio-occluso-distal (MOD) cavities were prepared. Group 2 remained unrestored. Group 3 was restored with packable resin composite using a single-step adhesive. Group 4 was restored with packable resin composite using a single-step adhesive and a thin layer of flowable resin composite. Group 5 was restored with packable resin composite using a total-etch two-step adhesive. Group 6 was restored with ormocer resin composite using a total-etch two-step adhesive. Group 7 was restored with an endodontic glass fibre post and hybrid resin composite using a total-etch two-step adhesive. Group 8 was restored with an endodontic zirconium post and hybrid resin composite using a total-etch two-step adhesive. The teeth were then mounted in a universal testing machine, the buccal cusp loaded (30 degrees ) until fracture, and the data analysed statistically.
  
  
  RESULTS
  Group 1 had the greatest fracture resistance, and group 2 the poorest. Groups 5-8 had significantly greater (P < 0.05) fracture resistance than groups 3 and 4. No significant differences were found between groups 3 and 4, or amongst groups 5-8 (P > 0.05).
  
  
  CONCLUSIONS
  For root filled maxillary premolars with MOD cavities, adhesive resin composite restorations, with and without glass and zirconium posts, increased the fracture resistance of the buccal cuSPS. A total-etch two-step adhesive increased significantly fracture resistance more than a one-step adhesive. For the one-step adhesive, an additional layer of flowable resin composite did not enhance fracture resistance.
authors.affiliation: Restorative Dentistry, School of Dentistry, Cumhurivet University, Sivas, Turkey. seydaher@hotmail.com
authors.forename: S H
authors.initials: SH
authors.lastname: Siso
authors.forename: F
authors.initials: F
authors.lastname: Hürmüzlü
authors.forename: M
authors.initials: M
authors.lastname: Turgut
authors.forename: E
authors.initials: E
authors.lastname: Altundaşar
authors.forename: A
authors.initials: A
authors.lastname: Serper
authors.forename: K
authors.initials: K
authors.lastname: Er
mesh_terms: D001641:Bicuspid; D003188:Composite Resins; D001840:Dental Bonding / Q000379:methods; D003737:Dental Cavity Preparation; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis; D006801:Humans; D008437:Maxilla; D011176:Post and Core Technique; D019228:Tooth Crown / Q000293:injuries*; D014082:Tooth Fractures / Q000517:prevention & control*; D019553:Tooth, Nonvital
chemical_list: D003188:Composite Resins