Vol 7, No 3, 2005 235 SEM Evaluation of the Cement Layer Thickness After Luting Two Different Posts Simone Grandini a /Cecilia Goracci b /Francesca Monticelli c /Andrea Borracchini d /Marco Ferrari e a Professor, Chair of Endodontics, University of Siena, Italy. b Chair of Dental Materials, University of Siena, Italy. c Clinical Professor, Department of Dental Materials and Restorative Dentistry, University of Siena, Italy. d Chair and Professor of Prosthetic Dentistry, University of Siena, Italy. e Professor of Dental Materials and Restorative Dentistry, University of Siena, Italy. Purpose: To verify with SEM the cement layer thickness and uniformity of resin-relined translucent fiber posts (anatomic posts) and standard translucent fiber posts. Materials and 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. Keywords: fiber posts, dental bonding, endodontically treated teeth. J Adhes Dent 2005; 7: 235–240. Submitted for publication: 06.08.03; accepted for publication: 02.12.04. Reprint requests: Dr. Marco Ferrari, Piazza Attias 19, Livorno, 57120, Italy. Tel: +39-0586-892283, Fax: +39-0586-898305. e-mail: ferrarimar@unisi.it he increasing popularity and widespread use of fiber posts is inevitably changing the procedure of recon- structing endodontically treated teeth. Since the introduc- tion of fiber posts in 1990, 7 many investigations have confirmed the good clinical performance of the system ad- T hesive/resin cement/fiber post 8,12 due to its good reten- tion values 1,6 and behavior under mechanical stress. 20 The evolution of fiber posts has accelerated since carbon and quartz fiber posts have been replaced by glass fiber posts, which are translucent and often radio- paque. The shape of these posts has also changed: from a double cylinder designed for retention purposes, to cylindrical (Endopost) and conical profiles (DT posts), based on the good performances of the new bonding pro- cedures. 15 The property of translucency proves favorable for luting purposes, as the transmission of light through the post allows the clinician to also use dual-curing cements. 13,24 Moreover, the wider choice of available shapes makes it possible to limit the amount of residual dentin that must be removed in order to achieve satisfactory post adapta- tion.