Fracture resistance and marginal gap formation of post-core restorations: influence of different fiber-reinforced composites

Abstract

Objectives The aim was to explore the fracture behavior and marginal gap within the root canal of endodontically treated (ET) premolars restored with different fiber-reinforced post-core composites (FRCs). Further aim was to evaluate the composite curing at different depths in the canal. Materials and methods Eighty-seven intact upper premolars were collected and randomly divided into six groups. After endodontic procedure, standard MOD cavities were prepared and restored with their respective fiber-reinforced post-core materials: group 1: prefabricated unidirectional FRC-post + conventional composite core; group 2: prefabricated unidirectional FRC-post + short fiber composite (SFRC) core; group 3: individually formed unidirectional FRC-post + conventional composite core; group 4: randomly oriented SFRC directly layered as post and core; group 5: individually formed unidirectional FRC + randomly oriented SFRC as post and core. After restorations were completed, teeth (n = 3/group) were sectioned and then stained. Specimens were viewed under a stereo microscope and the percentage of microgaps within the root canal was calculated. Fracture load was measured using universal testing machine. Results SFRC application in the root canal (groups 4 and 5) showed significantly higher fracture load (876.7 N) compared to the other tested groups (512-613 N) (p < 0.05). Post/core restorations made from prefabricated FRC-post (group 1) exhibited the highest number of microgaps (35.1%) at the examined interphase in the root canal. Conclusions The restoration of ET premolars with the use of SFRC as post-core material displayed promising performance in matter of microgap and load-bearing capacity. Clinical significance Fracture resistance of ET premolar restored by bilayered composite restoration that includes both SFRC as post-core material and surface conventional resin seems to be beneficial.

The influence of resin composite with high fiber aspect ratio on fracture resistance of severely damaged bovine incisors

“…The question then arises whether the light-cure SFRC material could have an adequate polymerization also inside the root canal. The surface microhardness (VH) of composites could help indirectly to evaluate the degree of the conversion of the monomer at different depth within the same composite 23,47) . In this study, the maximum VH of each tested core composites at the 0 mm depth (top surface layer) was considered as the baseline, which represented the best degree of conversion of each composite.…”

“…This was partly confirmed by Forster et al, and Fráter et al, in endodontically treated premolar teeth with class I cavity. In those studies, the directly layered SFRC post and core groups displayed promising performance in matter of fracture behavior 22,23) .…”

Characterization of restorative short-fiber reinforced dental composites

“…A number of manufacturers have developed short fiberreinforced composites (SFRCs) which claimed to overcome the weakness of conventional PFC. Many recent studies in the literature have approached to find way to support the remaining tooth structure and improve the durability of the final composite restorations [13][14][15][16] . The attempt has been to use SFRC as dentine-replacing material (bulk base) or post-core foundation under surface layer of enamel-replacing material (PFC), i.e.…”

“…To the author's knowledge, until now they are a limited number of SFRCs available in the market. These SFRCs perhaps mimic structurally the fibrous structure of dentine and some of them are recommended to use as bulk base or core build-up materials in large cavities of either vital or non-vital posterior teeth [14][15][16][17][18][19] .…”

Direkt restauratív technikák összehasonlítása MOD kavitással rendelkező fogakban üvegszálas anyagok felhasználásával – előzetes tanulmány

“…Gyakorlati szempontból fontos megemlíteni, hogy jelen vizsgálatban, a gyártó utasításainak megfelelően, az SFRC-t bulk fill anyagként egy rétegben helyeztük a kavitásba. Vizsgálatok bizonyítják, hogy az SFRC transzparens tulajdonsága és a rövid üvegszálak fényvezető tulajdonsága által az anyagot 4-5 mm mélységig át lehet megfelelően világítani, fotopolimerizálni [10,16].…”