title: Indirect composite preparation width and depth and tooth fracture resistance.
abstract: OBJECTIVE
  To evaluate the influence of preparation width and depth on the fracture resistance of teeth restored with one type of indirect composite restoration.
  
  
  METHODS
  Variations of depth and width were superimposed on a preparation of dentin design and dimensions with other variables including tooth size and morphology being controlled. Indirect composite restorations were constructed and placed in accordance with manufacturer's instructions. The restored teeth were subjected to compressive loading with fracture being induced by application of a 4 mm steel rod to the specimens in a universal testing machine, at a cross-head speed of 1 mm/minute.
  
  
  RESULTS
  Preparation depths of 3 to 4 mm were found to be preferable, but when the prevalence of severe tooth fracture was assessed, the shallower preparation depth was found to be indicated. Cavity depths of one-third and one-half bucco-lingual width were evaluated, the fracturing forces for the group with the narrower width being statistically lower.
authors.affiliation: Department of Restorative Dentistry, University Dental Hospital of Manchester, United Kingdom.
authors.forename: D C
authors.initials: DC
authors.lastname: Watts
authors.forename: N H
authors.initials: NH
authors.lastname: Wilson
authors.forename: F J
authors.initials: FJ
authors.lastname: Burke
mesh_terms: D000704:Analysis of Variance; D001641:Bicuspid; D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins; D003737:Dental Cavity Preparation / Q000009:adverse effects / Q000379:methods*; D005069:Evaluation Studies as Topic; D006801:Humans; D007284:Inlays / Q000379:methods*; D008422:Materials Testing; D014082:Tooth Fractures / Q000209:etiology / Q000517:prevention & control*
chemical_list: C075707:Brilliant Enamel; D003188:Composite Resins; C072541:Duo Cement; D017438:Bisphenol A-Glycidyl Methacrylate