Abstract:
This in vitro study evaluated the vertical fracture resistance of human extracted maxillary central incisors in six experiment groups. Two different types of luting cement (resin and zinc phosphate cement) and three different post materials (stainless steel, carbon fiber, and casted non-precious metal post) were used. The load was applied vertically at the cross-head speed 0.5 mm/min. All groups showed vertical root fracture except root that restored with cast post and core. Carbon fiber post cemented with resin cement showed the highest mean vertical fracture load at 3,517.30 +- 354.34 N, followed by stainless steel post cemented with resin cement, 3,368.90 +- 236.91 N, and carbon fiber post cemented with zinc phophate cement, 2,830.90 +- 236.91 N, respectively. Stainless steel post cemented with zinc phosphate cement provided the lowest mean vertical fracture load (2,549.60 +- 356.19 N). Statistic analysis by 2-way ANOVA (P is less than or equal to 0.05) showed that types of cement have an influence on vertical root fracture load. On the other hands, types of post showed no effect on vertical fracture load. There is also no interaction of post types and cement types on vertical fracture load. The majority of vertical root fracture patterns occurred in labio-lingual direction. The fracture line did not extend further than level of the post tip. Furthermore, there was no root canal cement or luting cement extruded into the fracture surface in every group of samples.
