title: SEM evaluation of the cement layer thickness after luting two different posts.
abstract: OBJECTIVE
  To verify with SEM the cement layer thickness and uniformity of resin-relined translucent fiber posts (anatomic posts) and standard translucent fiber posts.
  
  
  METHODS
  On 20 extracted maxillary anterior teeth, the roots were endodontically treated and prepared for the insertion of a fiber post. Translucent fiber posts (DT) were luted with a dual-curing resin cement (Duo-Link) in 10 specimens (group 1) after the canal walls had been treated with the One-Step bonding system. In the other 10 specimens (group 2), experimental anatomic posts (Anatomic Post'n Core) were tested. To these posts, a layer of light-curing resin is added to allow for a pre-cementation relining of the post, aimed at improving its fit into the endodontic space. For luting, the same adhesive-resin cement combination of group 1 was used. All the roots were sectioned and prepared for SEM observations. At the 1-mm, 4.5-mm, and 8-mm level of each root, cement thickness was measured, and the presence of gaps or voids within the luting material or at its interfaces was evaluated. A statistical analysis was performed to test the significance of differences in the cement layer thickness around the two types of post and at different levels of the same type of post.
  
  
  RESULTS
  In the presence of anatomic posts, the cement layer was significantly thinner and more uniform at the coronal and middle level of the root. In both groups, voids and bubbles were detected within the luting material, within the abutment material, and between fiber post and cement. Gaps were also visible between post and relining material.
  
  
  CONCLUSIONS
  The resin cement thickness was significantly lower in the anatomic post group than in the control group (standardized posts), except at the apical third of the canal, where there was no statistically significant difference. A good adaptation of anatomic posts was evident in all of the specimens.
authors.affiliation: University of Siena, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Grandini
authors.forename: Cecilia
authors.initials: C
authors.lastname: Goracci
authors.forename: Francesca
authors.initials: F
authors.lastname: Monticelli
authors.forename: Andrea
authors.initials: A
authors.lastname: Borracchini
authors.forename: Marco
authors.initials: M
authors.lastname: Ferrari
mesh_terms: D000704:Analysis of Variance; D003738:Dental Cements / Q000737:chemistry*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008689:Methacrylates / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011176:Post and Core Technique; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry*; D013499:Surface Properties
chemical_list: C103506:Bis-GMA, BPDM, HEMA dental-bonding resin; D003738:Dental Cements; D017220:Dentin-Bonding Agents; C431350:Duo-Link; D008689:Methacrylates; D019279:Resin Cements