[Impact of GuttaFlow Bioseal sealer on the vertical fracture resistance of oval-shaped canals].

Purpose: To investigate the effect of GuttaFlow Bioseal root canal sealer on the vertical root fracture resistance of oval-shaped root canals.

Methods: Sixty orthodontically subtracted maxillary and mandibular single-rooted premolar teeth were scanned with CBCT. Oval canals were eligible when the buccolingual diameter of the canal was greater than or equal to two times the mesiodistal diameter at a distance of 5 mm from the root apex. Thirty single-rooted premolars with oval-shaped root canals were prepared to F2 using the Protaper system and then randomly divided into the GuttaFlow Bioseal filling group and iRoot SP filling group. Each group was further divided for root canal filling using warm vertical compression, cold lateral condensation and single cone techniques. Five single-rooted premolars was chosen as a negative control group. After 30 days of storage in a constant thermotank at 37 ℃ and 100% humidity, the filled roots were vertically placed into a cylindrical model of self-polymerizing acrylic resin. Subsequently, the samples were fixed on the lower plate of a universal testing machine, and a ball of 4 mm in diameter was applied vertically with a downward pressure at a speed of 1 mm/min until fracture occurred. The load values were recorded in Newtons. The data were analyzed using SPSS 29.0 software package. Fracture patterns were examined under microscope.

Results: T test results showed no significant difference between the GuttaFlow Bioseal-filled and iRoot SP-filled groups (P=0.321). One-way ANOVA showed a significant difference in vertical fracture resistance between the groups(P＜0.05), and LSD analysis showed that the GuttaFlow Bioseal-filled sample teeth were significantly more resistant to vertical fracture than the iRoot SP when using the thermal vertical compression filling method and the single-tip method(P＜0.05). In contrast, the GuttaFlow BIoseal-filled group was significantly less resistant to vertical fracture than the iRoot SP group when using the cold lateral compression filling method(P＜0.05).

Concluisions: GuttaFlow Bioseal has the potential to improve root resistance to vertical fracture when filling root canals using the thermal vertical pressurization method and the single-tip method, but more clinical trials are needed to validate this result and its long-term prognosis.