| Objective: This in vitro study compared the effect of three prefabricated posts on the retention and fracture resistance and fracture patterns of endodontically treated teeth, Providing experimental basis for clinical application of domestically developed glass fiber post.Material and methods:1. Material: extracted human mandibular second premolar, domestic glass fiber posts (Beijing Sitelon science & technology development Co, Ltd), ParaPost? Fiber Lux glass fiber posts (Coltene/Whaledent Inc.), ParaPost XT prefabricated titanium posts (Coltene/Whaledent Inc.).2. Methods:2.1 Test of retention: Three types of posts were placed into root canal with their crowns removed, and cemented with resin-modified glass ionomer cement (RMGIC 3M ESPE). Each specimen was embedded in acrylic resin by metal cylinder on a level with the cementoenamel. The portion outside the root canals were fixed onto experimental equipment with a special jig. Constant tensile force was applied at crosshead speed of 1mm/min until the post was dislodged, the tensile force was recorded.2.2 Test of resistance to fracture: All teeth with their crowns removed were endodontically treated and restored with three different prefabricated posts and composite resin cores, and metal crowns were fabricated and cemented with Zinc Phosphate Cement (ZPC). Each specimen was embedded in acrylic resin by metal cylinder 2.0mm below the cementoenamel junction and then secured in a universal load-testing machine with a special jig. A compressive load was applied at a 45-degree angle to the long axis of the tooth, and the load is pointed to the middle of the lingual surface on the buccal cusp, until fracture occured, at a crosshead speed of 1mm/min. Fracture loads (N) and patterns (restorable and unrestorable) were recorded.Results1. The retention of domestic glass fiber posts is 114.5±15.848N, The retention of ParaPost? Fiber Lux glass fiber posts is 103.5±6.587N, The retention of ParaPost? prefabricated titanium posts is 147.1±11.13N. Significant differences were observed in retention among 3 groups (P=0.001<0.05).2. The fracture resistance of domestic glass fiber posts is 2.917KN, The fracture resistance of ParaPost? Fiber Lux glass fiber posts is 3.069KN, The fracture resistance of ParaPost? prefabricated titanium posts is 1.541KN. Significant differences were observed on the fracture resistance among 3 groups (P=0.001<0.05). Teeth restored with the two different glass fiber posts were observed 80% restorable fractures, whereas only 10% restorable fractures were observed in the teeth restored with prefabricated titanium posts.ConclusionWithin the limitations of this study, significantly higher retention and fracture resistance were recorded for endodontically treated teeth restored with domestic glass fiber posts in comparison with ParaPosts? glass fiber posts and titanium posts, which can be recommended as an alternative to esthetic post systems. |
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