title: The effect of cavity shape and hybrid layer on the stress distribution of cervical composite restorations.
abstract: OBJECTIVE
  The aim of this finite elemental stress analysis study was to evaluate the effect of cavity shape and hybrid layer on the stress distribution of the mandibular premolar tooth under occlusal loading.
  
  
  METHODS
  The mandibular premolar tooth was selected as the model based on the anatomical measurements suggested by Wheeler. Four different mathematical models were evaluated: 1) a saucer-shaped non-carious cervical lesion restored with a composite without a hybrid layer, 2) a saucer-shaped non-carious cervical lesion restored with a composite with a hybrid layer, 3) a wedge-shaped non-carious cervical lesion restored with a composite without a hybrid layer, and 4) a wedge-shaped non-carious cervical lesion restored with a composite with a hybrid layer. A 200 N force was applied from the buccal tubercule and central fossa of the premolar tooth. The findings were drawn by the SAPLOT program.
  
  
  RESULTS
  In models 2 and 4, the output showed that a hybrid layer acts as a stress absorber. Additionally, when the cavity shape was changed, the stress distribution was very different.
  
  
  CONCLUSIONS
  Cavity shape and hybrid layer play an important role in stress distribution in cervical restorations.
authors.affiliation: Department of Operative Dentistry and Endodontics, Faculty of Dentistry, Yuzuncuyil University, Van, Turkey.
authors.forename: Evrim
authors.initials: E
authors.lastname: Eliguzeloglu
authors.forename: Oguz
authors.initials: O
authors.lastname: Eraslan
authors.forename: Huma
authors.initials: H
authors.lastname: Omurlu
authors.forename: Gurcan
authors.initials: G
authors.lastname: Eskitascioglu
authors.forename: Sema
authors.initials: S
authors.lastname: Belli