Influence of the use and type of endo posts in the cervical stress level of central incisors submitted to the fatigue test. an in vitro study

Objectives: The objective of this study was to observe the biomimetic behavior of the fiber resin post and cast post in the cervical stress level of central incisors submitted to the fatigue test. A group of non-posted tooth was also evaluated. Methods: Thirty six recently extracted upper central insisors were selected. The teeth were divided in three groups. G1 – Cast post and core. G2 – Fiber resin post and composite core G3 – without post and core. Post was introduced 2/3 of the root. All groups were endodontically treated and recieved a full cast crown. G1 e G2 were cutted 1mm to the cervical limit. G3 was just restored with composite resin. For the fatigue test, the teeth were mounted in epoxy suports with a simulation of the periodontal lignment. The angle of test was 45º . An Instron 4444 (Universal Test Machine) was used for the compressive fatigue test. The maximun load was 60N. After the fatigue test, the groups were thermocycled and immersed in ethyle blue die for 24Hs. Results: were obtained after teeth sectining. The Kruskal-Wallis test was used. The average for each group was G1-3.0, G2-1.7, G3-4.6. A significante difference was observed (p<0,05) (T=16.25 and p=0,0003.) G2 had the best result. Conclusion: the study suggests that teeth with fiber resin post better resists the fatigue test than teeth with cast post or without post, under the specific conditions of the study. Supported by STM-UFSC. Used to obtain the Master of Science Degree.