Fracture resistance of over-flared root canals filled with MTA and resin-based material: an in vitro study|
Abdo, Salma B.; Masudi, Sam'an Malik; Luddin, Norhayati; Husien, Adam & Khamis, Mohd Fadhli
Aim: To measure the fracture resistance of over-flared roots filled with a variety of materials
(gutta-percha-nano HA, resilon-epiphany, composite and mineral trioxide aggregate - MTA)
using the Instron machine test and micro-computed tomography (Micro CT) Scan. In addition,
scanning electron microscopy (SEM) images were used to illustrate the type of fracture patterns
of the specimens.
Methods: One hundred and twenty extracted human mandibular singlerooted
premolars were selected. A total of 105 out of the selected teeth were prepared to the
working length and over-flared, leaving the apical 5 mm undisturbed. Fifteen samples had no
treatment and were used as a positive control group (Group +ve). The 105 test teeth were
further divided into 7 groups of 15 samples each. One of the 7 groups was designated as
negative control (Group -ve) where teeth were over prepared and left without obturation.
Remaining groups were filled with gutta-percha-nanoHA (Group1), gutta-percha-nano
HA+composite (Group 2), gutta-percha-nano HA+MTA (Group 3), resilon-epiphany (Group 4),
resilon-epiphany+composite (Group 5), and resilon-epiphany+MTA (Group 6). Fracture
resistance of all samples was measured using the Instron testing machine. Three samples from
each group had the depth of their fracture line measured by Micro CT Scan, and 2 samples from
each group had their fracture pattern illustrated using SEM.
Results: The highest fracture
resistance was observed in Group +ve, followed by Groups 3, 6, 5, 2, 4, 1, and Group -ve, with
values (in N) of: 1598 (641.0), 1190.5(424.2), 1164.7 (489.4), 821.2 (220.9), 683.4(179),
658.4 (211.3), 658.4 (99.0), 158.3(49.3), respectively. Statistical analysis for root fracture
resistance showed highly significant difference between all groups with p value < 001.
Conclusions: Micro CT Scan and SEM analysis indicated the ability of MTA to withstand
instron machine, scanning electron microscopy, micro CT scan, mineral trioxide aggregate