Objective:

To compare the compressive strength in premolars with root canal treatment, restored with metal post and customized fiberglass post, at different levels of ferrule.

Material and Methods:

It was made up of 48 uniradicular premolars extracted by orthodontic treatment, with similar characteristics, randomly divided into 6 groups of 8 specimens each group: Group 1: Metal post with no ferrule, Group 2: Metal post with 1mm ferrule, Group 3: Metal post with 2mm ferrule, Group 4: Customized fiberglass post with no ferrule, Group 5: Customized fiberglass post with ferrule 1 mm, Group 6: Customized fiberglass post with a 2 mm ferrule. The analysis was compared using ANOVA test and Tukey’s multiple comparisons with a significance level of 0.05.

Results:

Significant differences were found in the compressive strength of premolars restored with metal post and customized fiberglass post at the different levels of ferrule. The group with ferrule of 2 mm restored with a metal post, obtained an average value of 885.74 (± 104.10) and with a customized fiberglass post, an average value of 962.19 (± 104.10), being the highest value found in these comparisons; (p = 0.005).

Conclusions:

The level of ferrule in metal post and customized fiberglass post, contributes to compressive strength, 2 mm ferrule restored with metal post and customized fiberglass post; presented higher values of compressive strength unlike those of 0 mm and 1 mm.