الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The glass fiber post has become more popular and it is well accepted for the restoration of endodontically treated teeth because it has many adavantages as it is esthetically accepted, so, it is preferred to be used under all ceramic restorations.Also, its modulus of elasticity is similar to that of dentin, thus showing favorable mode of fracture.
Using various techniques of fiber post surface pretreatments can modify the surface energy characteristics of fiber posts and thus lead to increasing the bond strength of the resin-based luting agents to the fiber post surfaces.
Surface treatments of the fiber post result in roughness and increasing the surface area and energy of fiber post surface creating micropores for infiltration of resin cements and better wetting for bonding achieving micromechanical interlocking between the resin cement and the fiber post, also the use of coupling agents can increase the potential for the bonding between the resin cements and the fiber post.
Mechanical and chemical surface treatments can be used with fiber posts. The mechanical treatment includes airborne –particle abrasion and silica coating and the chemical treatment includes silanization , adhesive application and acid etching or the combination of both mechanical and chemical treatment.
This study was performed to evaluate the effect of different surface conditioners and cement types on the push-out bond strength of glass fiber posts to root dentin.
This in vitro study used forty-two extracted human single rooted teeth. The selected teeth were sound, caries-free and crack-free maxillary canines. Teeth of root length 14 mm were selected, while shorter teeth were discarded, so that this length was chosen to accommodate 3-4 mm of gutta-percha while providing 10 mm for the glass fiber post.
Root canal treatment was done for all the samples by the same operator for the purpose of standardization using protaper system rotary files. All root canals were irrigated with 2.5% sodium hypochlorite solution.
The used endodontic sealer was eugenol free, epoxy-resin based sealers because eugenol containing root canal sealer might inhibit the polymerization of the epoxy-resin based luting agent.
The post space was prepared using the specific Glassix-plus reamer size no 2 assigned by the manufacturer for the post used. Rubber stopper was placed on the drill shaft at a length of 10 mm from cemento-enamel junction leaving 3mm at at the apical part. The drill of the post system was mounted to a low speed contra angle hand piece which was held to ensure preparation of the post space parallel with the long axis of the root. After post space preparation, tooth was marked from external surface with a marker as indication of the end of the length of the fiber post.
Forty-Two teeth were classified into three main groups according to the type of surface conditioning of fiber posts as the following:
• group A: No surface conditioning and application of silane coupling agent only.
• group B:Immersion in 95% ethyl alchol for 10 minutes followed by application of silane coupling agent for 1 minute.
• group C: Immersion in 20% hydrogen peroxide for 10 minutes followed by application of silane coupling agent for 1 minute.
Each surface conditioning group were subdivided into two subgroups according to the type of resin cement used for cementation of fiber post as the following :
• Subgroup 1 : Self Etch Resin Cement e.g: Rely X Ultimate.
• Subgroup 2 : Self Adhesive Resin Cement e.g: G-CEM resin cement.
Results:
1- Chemical surface treatment of glass fiber posts enhanced bond strength of glass fiber posts to root dentin.
2- Self- etch resin cement showed higher bond strength values than self-adhesive resin cement.
3- Different root section location had a significant effect on the push out bond strength of glass fiber posts to root dentin.
Limiations :
1- Parallelometer was better to be used for post placement to ensure centralized positioning of glass fiber post inside the canal and to ensure uniform thickness of resin cement around the post.
2- Root section sample was better to be placed in a metal plate with the center of the post facing metal plunger on Universal testing machine .