RESUMO
A total of eighty freshly extracted human maxillary central incisors and canines were used for post hole preparation after been filled with gutta percha by the ordinary methods. Roots were divided into two groups. The first group was subjected to retention analysis, while the second to mechanical stress one. Each group of teeth was subdivided according to the post design into two subgroups; the first received threaded posts, ten of diameter 2 and ten of diameter 6. The second subgroup received casted posts, ten of diameter 2 and ten of diameter 6. The difference in post diameter had no significant effect on the retention of threaded posts while it played an important role in the casted ones. When both post designs subjected to a 450 angle load, fracture of the roots at their cervical one third occurred