Opções restauradoras para dentes com raízes fragilizadas e dentes com diferentes alturas e espessuras de remanescente coronário

Abstract

Teeth endodontically treated, wich reduced remaining structure, require the use of root retainer to provide retention to the coronal restoration. Several restorative options can be used, such as cast post and cores (CPC), fiber posts (FP) or anatomic posts (AP). There is no consensus regarding the best option for restoring teeth with reduced coronary thickness. Thus, the first study of this dissertation evaluated the effect of restorative strategy, height and thicknesses of the coronary remaining in the biomechanical behavior of endodontically treated teeth using the following groups: group CPC0: CPC and without remaining coronal structure, Group FP0: FP and without remaining coronal structure, Group CPCH1: CPC and remaining coronal structure (2 mm) with thickness more than 1 mm ; Group CPCL1: CPC and remaining coronal structure (2 mm) with thickness less than 1 mm; Group FPH1: FP and remaining (2mm) with thickness more than 1 mm; Group FPL1: FP remaining (2mm) with a thickness less than 1mm. With n= 12 for all groups. Survival tests were performed as well as fracture load tests and finite elements analysis. Data were submitted to the tests of Kaplan/ Meier and to ANOVA 1 factor followed by Tukey (a = 0.05). The groups CPC0 and FP0 showed, lower survival rates than the other groups (p = 0.000). The ANOVA showed, higher values for the groups CPCH1 and FPH1 compared to the other groups. (p = 0.0043). The finite elements analysis showed better stress distribution in those groups with coronary remaining structure and restored with fiber glass. It was concluded that teeth without remaining coronary and with a thickness less than 1 mm remaining presented the worse biomechanical prognosis.The second study aimed to evaluate the fracture resistance and failure mode of weakened roots restored with CPC, FP and AP through a systematic review. Searches were made in MEDLINE / PubMed and Scopus, seeking laboratory studies that evaluated the fracture resistance of weakened roots restored with at least two of the strategies mentioned above. The means of fractured resistance values were obtained and the following comparisons done: CPC x FP, CPC x AP and FP x AP. After the selection process only five articles were included in this study. There was no significant difference between the fracture resistance values among the restorative strategies, however more catastrophic failures were observed for the metal cast post and core. The included studies showed low bias risk for most domains assessed. Therefore, it was concluded that the load required for fracture did not depend on the strategy used and teeth restaured with CPC present greater chance of catastrophic failure.