Abstracts of the Academy of Dental Materials Annual ... - IsiRed

land); Thermafil: non-standardized 06-30 cones with plastic
carrier heated in the Thermaprep Plus oven (Dentsply Maillefer,
Baillagues, Switzerland). Following obturation, the two
halves of each model were separated and photographed using
a digital camera (Nikon ® D50 Macro lens with 105 mm f
2.8). The gutta-percha filling ability was evaluated at 2, 4,
6, and 8 mm from the established apex length by assigning
the following scores: lateral grooves: 0 = absence of material,
1 = presence of material; dentin depressions: 0 = absence of
material, 1 = partial filling, 2 = total filling. Scores at lateral
grooves and dentin depressions were statistically compared
among techniques at the same level and among levels within
the same technique (Kruskal–Wallis ANOVA, Dunn’s Multiple
Range test, p < 0.05).
Results:
Level Dentin depression scores: median (25–75%)
Thermafil GuttaFlow System B
2 mm 0.5 (0–1) a 1 (0–1) aA 2 (2) b
4 mm 0.5 (0–1) a 2 (2) bB 2 (2) b
6 mm 0 (0) a 2 (2) bB 2 (2) b
8 mm 0 (0–0.5) a 2 (2) bB 2 (2) b
Level Lateral grooves scores: median (25–75%)
Thermafil Guttaflow System B
2 mm 0 (0) a 0 (0) aA 1 (1) b
4 mm 0 (0) a 1 (1) bB 1 (1) b
6 mm 0 (0) a 1 (1) bB 1 (1) b
8 mm 0 (0) a 1 (1) bB 1 (1) b
In the table different small letters label statistically
significant differences among techniques at the same
level, while different capital letters label statistically significant
differences among levels within the same technique.
Conclusions: The GuttaFlow and System B techniques
exhibited a significantly better gutta-percha filling ability than
Thermafil, particularly at 4, 6, and 8 mm from the established
apex length.
doi:10.1016/j.dental.2010.08.155
148
In vitro loading curve of an orthodontic distalizing spring
D. Dalessandri, L. Laffranchi, F. Zotti, S. Bonetti, L. Visconti
University of Brescia, Italy
Objectives: The objective of this in vitro study was to individually
evaluate the force delivered by a no compliance molar
distalizing appliance, the Frog, before its clinical use. We
tested five different springs made out of 0.032-in. iron wire. In
a second time we compared these springs with other 0.032-in.
alloy wires: TMA and blu-nickel.
Materials and methods: Different types of springs has
been evaluated by the Instron machine 54848, an engineer-
dental materials 26S (2010) e1–e84 e69
ing system that is able to describe their mechanical behaviour
registering the value of force sourcing from the appliance activation
by the original screw driver. In vitro simulation is based
on a custom built support for the Frog screw, where the spring
is plugged in, that allow to apply the controlled load on the
supposed first upper molar palatal tube position, at the end of
the spring.
Results:
Activation SS mean TMA mean BN mean
1 mm 50.99 gr 10.20 gr 20.39 gr
2 mm 81.58 gr 20.39 gr 40.79 gr
3 mm 101.97 gr 40.79 gr 71.38 gr
4 mm 132.56 gr 50.99 gr 101.97 gr
5 mm 163.15 gr 71.38 gr 132.56 gr
6 mm 183.55 gr 81.58 gr 163.15 gr
7 mm 198.34 gr 90.21 gr 186.79 gr
Conclusions: According to most of the literature about
molar distalization, the bilateral first upper molar distalization
requires 300 gr of force. To gain this value with a personalized
Frog spring this study showed that 9 rotations of the screw
were needed. Iron preformed 0.032-in. springs express high
values of strength with few activations, so they have a low risk
of plastic deformation and they are indicated for this kind of
appliance.
doi:10.1016/j.dental.2010.08.156
149
Intraradicular marginal integrity of fiber posts relined and
fixed with composite resin
M.F. De Goes, A.C.R.L. Caiado, M.C. Alves, F. Souza-Filho
Dental School of Piracicaba-University of Campinas, SP, Brazil
Objectives: The dislodging of fiber posts from the root canal
is the main cause of failure of fiber post-retained restorations.
This study evaluated the marginal integrity of Fiber Reinforced
Posts (FRP) confectioned using a conventional technique (CT)
or an anatomic composite relining technique (ACRT) and
cemented with a self-adhesive resin cement or a conventional
dual-cure resin cement in the presence or absence of
light.
Materials and methods: Bovine incisors had crowns
removed. Roots were endodontically prepared using saline
solution. Apexes were sealed externally with composite resin
and post spaces were prepared 15 mm deep. Samples were
randomly assigned to 8 experimental groups (n = 10) according
to FRP technique used (CT or ACRT), adhesive cement
employed (Unicem (U) or Scotch Bond Multipurpose + Rely X
ARC (R)) and activation mode (light-cure or self-cure). After
48 h, roots were longitudinally sectioned, surfaces were polished
and impressions were taken for replication using epoxy
resin. The length of the post inside the root canal was divided
on the replicas into three (cervical-C, middle-M and apical-
A) thirds. After obtaining baseline impressions, roots were
immersed in a solvent solution of methyl ethyl ketone and