Influence of intraradicular post and crown ferrule on the fracture strength of endodontically treated teeth

Abstract

The aim of this study was to investigate the fracture strength of endodontically treated teeth restored with different posts and variable ferrule heights. Sixty freshly extracted human canines were treated endodontically and randomly assigned to 6 groups (n=10), being restored with custom-made cast post-and-core (CP0 and CP3 groups), prefabricated post and composite resin core (PF0 and PF3 groups), and composite resin (CR0 and CR3 groups). The CP0, PF0 and CR0 groups presented no ferrule and the CP3, PF3 and CR3 presented 3 mm of coronal structure. All teeth were restored with full metal crowns. The fracture strength was measured in a universal testing machine at 45 degrees to the long axis of the tooth until failure. Data were analyzed statistically by 2-way ANOVA and Tukey's test (alpha=0.05). When the mean fracture strength values were compared (CP0 group - 820.20 N, CP3 group - 1179.12 N; PF0 group - 561.05 N; PF3 group - 906.79 N; CR0 group - 297.84 N; and CR3 group - 1135.15 N) there was statistically significant among the groups (p<0.05), except for the three groups with 3 mm of coronal remaining, which were similar to each other. The results of this study showed that the ferrule in crowns promoted significantly higher fracture strength in the endodontically treated teeth.

Ferrule Effect: A Literature Review

“…Type of Post and Core System and Final Restoration. The effectiveness of different procedures for restoring the function of endodontically treated teeth subjected to static (13,30,32,(40)(41)(42)(43)(44)(45)(46) or fatigue loading (47)(48)(49)(50)(51)(52) has been widely investigated. Combinations of different ferrule designs and various post and core systems and final restorations were tested in an attempt to find the best treatment option that would provide the highest fracture resistance and the most favorable fracture pattern of severely compromised teeth.…”

“…However, the results were controversial. Some research reported that changes in stiffness and design associated with post and core material did not significantly influence fracture resistance as long as sufficient dentine structure remained (13,41,47,49,52), whereas other studies pointed out that post type may have an impact (32,(42)(43)(44)(45)50).…”

“…The vast majority of literature data suggests that the presence of a ferrule is a significant factor in improving resistance to fracture for different types of posts: cast post and core (13, 33, 36, 40-43, 48, 53), all ceramic post and core (40), prefabricated metallic posts (30,34,41), and prefabricated fiber-reinforced composite (FRC) posts (13,29,46,48,54). Conversely, two studies reported that the additional use of ferrule preparation had no benefit in terms of resistance to fracture of teeth restored with cast post and core (43) and prefabricated metallic post (55).…”

Pesagem de dentes humanos úmidos, com cones de papel e estufa

“…Mais ainda, pesquisas realizadas para averiguar resistência a fraturas em dentes tratados endodonticamente com diferentes pinos e diferentes alturas do remanescente dentinário da coroa apontam a necessidade da realização da secagem dos canais radiculares com cones de papel absorvente estéril após preparo químico--cirúrgico dos canais radiculares 15 . É claro que a secagem do canal realizada por Faria-Silva et al 17 (2010) com sistema convencional promoveu maior remoção de debris em todo o terço apical, e subsequente maior limpeza, porém, foi mais efetivo o sistema a vácuo na limpeza a 1,5 milímetros apicais de canais radiculares de molares.…”

“…Pereira et al 15 (2009) propuseram avaliar a resistência à fratura de 60 dentes caninos humanos extraídos os quais foram tratados endodonticamente e restaurados com diferentes pinos em diferentes alturas de remanescente dentinário da coroa. A instrumentação foi feita utilizando-se uma lima tipo K número 20 a 1mm aquém do ápice e técnica step-back feito até a lima 35.…”