BACKGROUND:The combination of fiber post and resin core for restorations of mesial or distal defects of the maxil ary central incisor can restore the elastic modulus close to the nature dentin, and achieve good aesthetic effects. However, when a complete dentin col ar cannot be prepared due to a large number of dental tissue defects, the post and core are easy to be lost or fractured after defect repair using the combination of fiber post and resin core.
OBJECTIVE:To compare the stress distribution after nickel-chromium cast post and core, gold-pal adium cast post and core, and fiber post and resin core were used for restorations of mesial or distal defects of the maxil ary central incisors using three-dimensional finite element analysis.
METHODS:An intact adult maxil ary central incisor that meets the average dental anatomical value in China was selected and scanned using a dental cone-beam CT. Then, three-dimensional tooth-fiber post and core (nickel-chromium cast post and core or gold-pal adium cast post and core)-al-ceramic crown models of mesial or distal defects of the maxil ary central incisors and part loss of dentin col ar were established using ABAQUS analysis. After repair with nickel-chromium cast post and core, gold-pal adium cast post and core, and fiber post and resin core, stress distribution in the loaded state was compared using the ABAQUS three-dimensional finite element analysis.
RESULTS AND CONCLUSION:The stress peak at the adhesive and cast layers in the fiber post and resin core group was significantly lower than that in the nickel-chromium cast post and core or gold-pal adium cast post and core group. It indicated that the tooth root was easy to be fractured after mesial or distal defects of the maxil ary central incisors with partial loss of dentin col ar were restored with nickel-chromium cast post and core, gold-pal adium cast post and core. In addition, the stress peaks at the dentin layer were consistent for fiber post and core, nickel-chromium cast post and core, and gold-pal adium cast post and core. These findings indicate that the combination of fiber post and resin core is better for restorations of mesial or distal defects of the maxil ary central incisors.