Al-Hajj, Mohammed Nasser Ahmed
(2022)
A novel moldless sintering porous titanium for dental post system: development, characterization and evaluation of mechanical properties.
PhD thesis, Universiti Sains Malaysia.
Abstract
Different types of intraradicular posts are available to restore the endodontically-treated teeth. However, debonding of the post is still the main drawback till date. In this study, we developed a porous titanium dental post with porosity to increase the flexibility of the post, and with porous surface to improve the micro-interlocking with the luting cement. In the first part, pure titanium powder was mixed with wax binder (as space holder) in three different percentages (85%, 90%, and 95% wt. titanium powder). The samples were exposed to heating temperature through two phases. In the first phase (air heating), the samples were heated in an open-air environment for 2 hours (at 380◦C) to remove the wax binder. In the second phase, the samples were sintered in a tube furnace with argon environment for 10 hours (at 1100◦C) to complete the process. The samples were then characterized and tested to select the best mixture for further investigation. The field-emission scanning electron microscopy (FESEM) showed good roughness of the surface and thorough porosity of the structure, with better melting of the titanium particles in the 85% group. The energy dispersive X- ray spectrometry (EDX) analysis showed higher percentages of titanium within the material. The density values were close to the theoretical ones, and the porosity revealed good distribution with less than half of the volume (40%). The compressive and flexural strength tests revealed higher values of 85% group than other groups. The 85% group was then selected to fabricate the porous titanium post (PTP). In the second part, 96 extracted human teeth were collected to investigate the push-out bond strength of the porous post. Two different luting cements (RelyX U200TM 3M
ESPE and ParaCore® Coltene Whaledent) were used and the roots were sectioned at the coronal and middle levels (3.00 ± 0.2 mm thickness). The push-out bond strength of the PTP was compared to other dental posts (Coltene Whaledent) namely commercially-pure titanium post (CTP) (ParaPost® XP), stainless steel post (SSP) (ParaPost® XP), and fiber glass post (FGP) (ParaPost® Fiber Lux). The push-out bond strength values of PTP were comparable to that of the other posts, with no significant differences (P> 0.05) in RelyX U200 group at both sections of the root. The adhesion of PTP was better than the other posts, with no prevalence of post-cement failure in PTP. FESEM images on the post-cement-dentin interface showed better adhesion of PTP to both types of cements, with no visible separating line between post and cement. The findings of this study provide a possibility to use the porous titanium post as alternative option for dental post systems.
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