Int Poster J Dent Oral Med 2007, Vol 09 No 04, Poster 378
Effect of cyclic loading on bond strength of fibre posts
Dr. Katrin Bekes, Dr. Christian Ralf Gernhardt, Prof. Dr. Hans-Günter Schaller,
Department of Operative Dentistry and Periodontology, Martin-Luther-University Halle-Wittenberg
September 13-16, 2006
IADR Pan European Federation 2006
The use of prefabricated posts for restoration of endodontically treated
teeth is a common and well described therapy in clinical practice (1). Fibre
posts are frequently used for esthetic restorations. Usually, posts are
cemented in one or more prepared root canals, providing retention of the
core built-up and making a final prosthetic restoration of the tooth
possible (2). Furthermore, they might increase the stability of the tooth
(3).The retention of root canal posts is a major factor influencing the
long-term success of the final restoration. It depends on different factors
like design, length and surface texture of the post as well as on the
properties of the used cement (1).
The aim of this study was to evaluate the effect of cyclic loading on the
bond strength of the fibre post D.T. Light Post using different post
diameters (Figure 1,2).
|Fig. 1: DT Light Post System (VDW, Germany)
||Fig. 2: DT Light Post #2 and the correponding burs.
Material and Methods
Sixty freshly extracted single rooted were included in this study. They
were selected for standar size and quality. During the whole experimental
period the teeth were stored in 0.9% saline. The root canals of the teeth
were treated endodontically. Between each preparation step the canals were
irrigated with 1% sodium hypochlorite and chlorhexidine digluconate (2%
solution). root canals of the teeth were treated endodontically. Between
each preparation step the canals were irrigated with 1% sodium hypochlorite
and chlorhexidine digluconate (2% solution). After that, the root canals
were filled with laterally condensed gutta-percha and AH Plus sealer
(Dentsply DeTrey, Germany). Finally, the teeth were sectioned perpendicular
to their long axes to the cementoenamel junction. All specimens were
assigned to three experimental groups and post holes were prepared with the
corresponding burs: A: DT Light Post 1 (A1: immediate loading, A2:
100 cycles), B: DT Light Post 2 (B1: immediate loading, B2: 100
cycles), C: DT Light Post 3 (C1: immediate loading, C2: 100
cycles). The preparation depth was adjusted to 10 mm in all groups. After
evaluation of the post fitting the canal was desinfected with chlorhexidine
digluconate (2% solution) und thoroughly dried with the corresponding paper
points (Roeko). The posts were cleaned using 70% ethanol before cementation.
Cementation was done using Panavia 2.0. After insertion of the post into the
canal excess was removed. Polymerization was performed using the
polymerization lamp Optilux for 60 seconds. After that, the specimens were
stored dry in an incubator for 7 minutes at 37°C, followed by 24 h storage
in saline. Tensile tests were carried out using a universal testing machine
(Z005, Zwick; crosshead speed 1 mm) (Figure 3-5). Each group was subdivided
into two subgroups (1 and 2): 1: immediate loading to maximum bond strength;
2: maximum load after 100 cycles (between 10 and 20 N). Bond strengths (N)
were recorded from a personal computer and statistically analyzed using the
des Tukey's Test (SPSS Inc., Chicago, USA).
||DT Light Post #1
||DT Light Post #2
||DT Light Post #3
|Fig. 3: Special designed experimental apparatus to test bond strength.
||Fig. 4: Testing device before loading.
||Fig. 5: Testing device after loading.
Recorded bond strengths (in N and MPa) are shown in Table 1 and Figure 6.
Analysis of variances test revealed that the post diameter did not affect
the bond strengths the fibre posts of the D.T. Light Post system (p< 0.05,
tukey's test). pairwise comparison showed that loading after 100 cycles
decreased the bond strengths of the posts (p< 0.05, tukey's test).
| In MPa
|Tab. 1: Bond strengths within the different groups (mean value and standard deviation).
|Fig. 6: Mean value and standard deviation within the different groups.
The D.T. light post system showed acceptable tensile bond strengths. The
use of different post diameters did not affect the bond strength in MPa.
Focusing on the strengths in N bigger diameters showed higher bond strengths
than smaller diameters. Cyclic loading decreased the bond strengths of all
diameters of fibre posts used.
- Edelhoff, D., Spiekermann, H., Yildirim, M.: Klinische Erfahrungen mit konfektionierten Wurzelstiften und individuellen Stumpfaufbauten aus Keramik. Dtsch Zahnärztl Z 55, 746-747 (2000).
- Hew, Y.S., Purton, D.G., Love, R.M.: Evaluation of pre-fabricated root canal posts. J Oral Rehabil 28, 207-211 (2001).
- Morgano, S.M.: Survival rate and failure characteristics for two post designs. J Prosthet Dent 73, 439-444 (1995).
MPa = Megapascals
This Poster was submitted by Dr. Katrin Bekes.
Dr. Katrin Bekes
Department of Operative Dentistry and Periodontology
Grosse Steinstrasse 19