Contrastive Study Of Tensile Strength Between Different Composites Resin Core And Fiber Posts

Objective:Explore the difference of adhesive strength between three kinds of resin core materials and RTD fiber posts by mechanics experiment. Compare the restorative effects between three kinds of resin core materials and RTD fiber posts through clinical cases observation. Provide a reference for clinical scientists choosing suitable resin core materials.Methods:This study choose three nuclear materials to research, and was divided into mechanical experiment in vitro and clinical cases observation.The mechanical experiment part:Prepareing 30 RTD fiber posts 15mm in length and lmm in diameter, and cleaning with the 75% ethanol before made post-core specimens. After drying the posts, brushed the 3M Adper Single Bond 2 on the fiber posts’surface evenly. Lighted every fiber post for 20s by curing light and saved them. The fiber posts that have prepared were randomly divided into 3 groups, each group containing 10 specimens. (Group A:RTD fiber post+RTD Corecem; group B:RTD fiber post+DMG LuxaCore; group C:RTD fiber post+PULPDENT Resin Cement) The fiber posts were vertically placed in the center of transparent plastic tube which was 5mm in diameter and 5mm in height. Then each group of resin core materials were filled into the plastic tube in two.layers. Lighted each layer for 40s by curing light. Removed the post-core specimens from the plastic pipe after fully cured. Grinded, polished and reshaped the post-core specimens into uniform size,5mm in diameter and 5mm in height. The undesirable one should redo. Next step was put the post-core specimens into the thermostat with artificial saliva, and the immersion should keep in (37±1)℃ for 24 hours. Removed the specimens that has immersed, and dried them The post-core specimens were fixed on the microcomputer control electron universal testing machines and were subjected to a tension load at lmm/min continuous speed until the post and core to be separated. The biggest failure load were recorded.The clinical cases observation part:Select patients whose anterior and premolar need post-core crown restoration. There were 32 adult patients in total, including 13 men and 19 women. They are between ages of 12 and 19. The average age was 39 years old. There were 32 teeth in total, including 35 anterior teeth and 19 premolar teeth. The cases were divided into three groups. Group A contained 11 patients and a total of 17 teeth, and using RTD corecem to restore teeth. Group B contained 10 patients and a total of 19 teeth, and using DMG luxacore z-dual to restore teeth. Group C contained 11 patients and a total of 18 teeth, and using Pulpdent embrace wetbond resin cement to restore teeth. All the teeth were repaired by fiber posts and resin cores, and made restorations. It need a 12 months follow-up after restoration, and to return visit every six months. Checked the condition of restoration, root, gums, and so on; to evaluate the efficacy of the repair.Results:The mechanical experiment part:The mean values of adhesive strength between different composites resin core and fiber posts were different. The strength of Resin cement was the highest, followed by the Corecem, the lowest was the Luxacore. Although the several groups of data were different, but the difference was small. Tensile strength of the three groups were not significantly different (P=1.56>0.05) by the analysis of One-Way ANOVA. The S-N-K method displayed the results in the same column, meaning the adhesive strengths were not significantly different.The clinical cases observation part:After 12 months of clinical observation, the success ratio of the reparation of group A was 94.12%. There was 1 case appeared crack on the restoration, without other symptoms. Group B’s success ratio of the reparation was 94.74%. There was 1 case appeared fiber fracture, without root fractured. The success ratio of the reparation of group C was 94.44%. There was 1 case appeared fiber post and resin core be separated, and the fiber post was retained in the teeth perfectly. The above 3 cases of failure were appeared in the front teeth and premolars were all successful repaired.Conclusion:The tensile strengths between RTD corecem、 DMG luxacore、Pulpdent resin cement and RTD fiber post were high. Even without using its supporting products and using the same bond, the resin core materials and fiber posts also have achieved good adhesive strengths. Clinicians could choose resin core materials that made by different manufacturers more freely. These three kinds of resin core materials of the study can meet the clinical demand. They were all reliable and effective, that can be widely applied.