Failure modes of Y-TZP abutments with external hex implant-abutment connection determined by fractographic analysis - Basılio, Mariana de Almeida; Delben, Juliana Aparecida; Cesar, Paulo Francisco; Rizkalla, Amin S; Santos Júnior, Gildo Coelho (Journal of the Mechanical Behavior of Biomedical Materials, 2016)