Effect of ferrule location on the fracture resistance of crowned mandibular premolars: An in vitro study.

STATEMENT OF PROBLEM: How the location of a ferrule affects the fracture resistance of endodontically treated mandibular premolars is unclear.

PURPOSE: The purpose of this in vitro study was to compare the effect of ferrule location on the fracture resistance of endodontically treated mandibular premolars.

MATERIAL AND METHODS: Seventy-two extracted human mandibular premolars were selected and divided into 6 test groups (n = 12) according to ferrule location: control group, GHT; endodontically treated teeth without endodontic posts and crowns, GCF; teeth with a 2 mm circumferential ferrule, GBF; teeth with a 2 mm buccal ferrule; GLF, teeth with a 2 mm lingual ferrule; GBLF, teeth with a 2 mm buccal and lingual ferrule; and teeth without ferrule, GWF. After glass fiber posts were cemented with a self-adhesive resin cement and foundation restorations were placed, NiCr crowns were luted to each prepared tooth. All specimens were quasistatically loaded at 30 degrees in a universal testing machine until fractured. Data were then analyzed with 1-way ANOVA, followed by multiple comparisons using the Tukey honestly significant difference test (α=.05).

RESULTS: Mean ± SD failure loads for groups ranged from 791.1 ± 177.5 N to 1086.1 ± 181.1 N. One-way ANOVA revealed a statistically significant difference between the groups (P ≤ .05). However, no statistically significant differences were observed among groups (P > .05), except between GHT (control group) and groups GBLF and GWF (P = .025, P = .022).

CONCLUSIONS: Within the limitations of this study, the location of the ferrule had no significant effect on the fracture resistance of endodontically treated mandibular premolars.