Luca Giachetti

Translucent fiber post cementation using light- and dual- curing adhesive techniques and a self-adhesive material: Push-out test

OBJECTIVES To compare, by means of the push-out test, the interfacial strength of two dual resin cements and one light-curing cement when used in translucent fiber post cementation. METHODS Thirty-nine, endodontically treated, single canal, extracted human bicuspids were selected. Translucent fiber posts (RelyX Fiber Post) were luted into the root canal using three resinous luting systems (n=13). Dual-curing technique (DC): the specimens were treated with Excite DSC and RelyX ARC, which were light-cured simultaneously through the post for 60s. Self-adhesive dual-curing technique (SADC): the specimens were treated with RelyX Unicem, which was light-cured through the post for 60s. Light-curing technique (LC): the specimens were treated with Excite DSC and Tetric Flow, which were simultaneously light-cured through the post for 60s. The specimens were transversally sectioned into six slices in order to perform the push-out test. Data were analyzed by two-way ANOVA followed by the Tukey-Kramer test for post-hoc comparisons at alpha=0.05. RESULTS At every region, results did not show any statistical difference between the DC and LC techniques. With the LC technique bond strength values were lower at the apical region than those recorded at the coronal and middle regions. At the coronal and middle regions, bond strength values for the SADC technique were lower than those resulting when using the other two techniques. At the apical region, there was not significant difference in bond strength between the luting techniques tested. CONCLUSIONS The interfacial strength between light-curing cement and root canal is equivalent to the interfacial strength between dual-curing cement and root canal.

Push-out strength of translucent fibre posts cemented using a dual-curing technique or a light-curing self-adhering material

AIM To compare by means of a push-out test the interfacial strength of a dual-curing resin cement and a light-curing self-adhering resin composite when used in translucent fibre post cementation. METHODOLOGY Thirty-four extracted human premolars with single canals were selected and root filled. Translucent fibre posts (RelyX Fiber Post) were luted into the root canal using two resinous luting systems (n = 17). Dual-Curing Technique (DC): the specimens were treated with Excite DSC and RelyX ARC, which were light-cured simultaneously through the post for 60 s. Light-Curing Self-Adhering Technique (LCSA): the specimens were treated with Vertise Flow, which was light-cured through the post for 60 s. The specimens were sectioned transversally into six slices to perform the push-out test at the coronal, middle and apical regions of the root canals. Data were analysed by two-way anova. All specimens were analysed by stereomicroscopy and SEM to determine fracture patterns. RESULTS There were no significant differences between the DC and LCSA techniques (P = 0.703) in any of the canal regions. Root region was not a significant factor for push-out values (P = 0.255) and group-region interactions were not significant (P = 0.740). For the DC technique, the majority of the fracture patterns (73.3%) were adhesive at the interface between dual-curing resin cement and adhesive. For the LCSA technique, the majority of the fracture patterns (71.7%) were adhesive at the interface between light-curing self-adhering resin composite and dentine. CONCLUSIONS The interfacial strength between light-curing self-adhering resin composite and root canal walls is equivalent to the interfacial strength between dual-curing cement and root canal walls.

Reparability of Aged Silorane With Methacrylate-Based Resin Composite: Micro-Shear Bond Strength and Scanning Electron Microscopy Evaluation

OBJECTIVES To evaluate the compatibility between aged siloranes and methacrylate-based composites by simulating a common repair-technique. METHODS Twenty substrates were constructed using silorane (Filtek Silorane, 3M ESPE) and methacrylate composites (Filtek Supreme XT, 3M ESPE). Substrates were aged in 0.9% NaCl solution at 37°C for 72 hours. Silorane build-ups were constructed on silorane substrates without any intermediate layer (IL). Methacrylate build-ups were constructed on silorane substrates without any IL, with a methacrylate IL (Heliobond, Ivoclar Vivadent), or with a phosphate-methacrylate IL (Silorane System Adhesive Bond, 3M ESPE). Methacrylate build-ups were also constructed on methacrylate substrates without any IL. The micro-shear bond strength test was carried out after thermocycling. Bond strength data were statistically analyzed using analysis of variance and Tukey post hoc tests. Failure modes were assessed by means of scanning electron microscopy observations. RESULTS The silorane-methacrylate group without any IL showed the lowest bond strength values (0.4 ± 0.1 MPa). The use of a methacrylate-based IL (1.6 ± 1.7 MPa) led to a slight increase in bond strength, whereas the use of phosphate-methacrylate IL (9.1 ± 5.4 MPa) significantly increased bond strength. There was no statistically significant difference in bond strength between silorane-silorane (7.9 ± 3.6 MPa) and methacrylate-methacrylate (9.5 ± 4.1 MPa) groups without any IL.

An 8-year follow-up of a fractured endodontically treated incisor restored with a modified laminate veneer.

This clinical report describes the restoration of a left maxillary first incisor using an all-ceramic one-piece coronal post and a laminate veneer feature. This proposed restoration technique represents an alternative to traditional restoration procedures such as metal-ceramic restorations, all ceramic crowns and porcelain laminate veneers. This restoration preserves the remaining tooth structure, re-establishes function and offers good esthetic results.

Rehabilitation of severely injured anterior teeth in a young patient using ceramic and FRC: a clinical report

This clinical report describes the indirect restoration of anterior teeth in a young patient after a severe dental trauma using all-ceramic coronal posts. Step-by-step clinical procedures and their rationale are described. The learning objective of this case report is to outline the principles for the management of traumatic injuries of permanent anterior teeth in young patients to re-establish function and provide good esthetic results.

Double microtensile bond strength test: an alternative methodology for sample preparation

The aim of the present study was to compare the technique currently used for carrying out the microtensile bond strength (muTBS) test with an alternative method. Six human molars were sectioned transversally to obtain two specimens from each tooth: a 0.75-mm-thick slab of mid-coronal dentin, which presented an occlusal and a cervical surface (DS specimen); and the remaining section of the tooth with an exposed dentin surface (SS specimen). A self-etch adhesive system and four layers (2 mm each) of resin composite were applied to the sectioned surfaces by means of a custom-made special device, in order to obtain a cylindrical build-up. Each specimen was sectioned lengthwise to obtain multiple sticks. The end sections of sticks obtained from DS specimens were resin composite, whereas the middle section was dentin. The sticks obtained from SS specimens were half resin composite and half dentin. The specimens were fractured under tension. Data were subjected to a multilevel statistical model. The maximum load at break of SS specimens was higher than that of DS specimens. This modified methodology offers two main advantages over the traditional procedure: easier manipulation of the sticks; and the possibility of testing deep dentin.