Table of Contents:
Objective and purpose
A root canal treatment is a common therapy in the dental practice. This is usually the only
way to preserve the tooth in the long-term. The success rate of endodontic treatment has
increased in the last years. There is evidence for 10-year survival rates of between 85 and 93%. The success and the patients satisfaction can be attributed to effective root canal
treatment and to the appropriate decision regarding post-endodontic therapy.
Due to access cavity preparation tooth suffers considerable loss of sound hard tissue.
The fracture risk of the remaining hard tooth tissue is dramatically increased. In the worst
case, the tooth has to be extracted after vertical fracture. Post-endodontic restorations aim
to stabilize the remaining hard tooth tissue in order to complete the biomechanical stability
of the tooth and to eliminate bacterial recontamination. The question which restoration is
the best option for root canal treated teeth is still open to debate. Dentists are uncertain in
choosing a definitive therapy and patients demand esthetic restorations. More and more
scientific research is being done with regard to ceramic and resin composite materials.
Materials und Methods
96 freshly extracted human third molars (n=8) were stored in destilled water.
11 experimental series and one control group were investigated. After the access cavity
preparation, root canals were filled and the teeth were restored with following materials:
Resin composite direct (Tetric EvoCeram Bulk Fill, Ivoclar Vivadent), ceramic indirect
(IPS Empress, Ivoclar Vivadent; e.max CAD, Ivoclar Vivadent; Celtra Duo, Dentsply DeTrey),
Hybrid Nano Ceramic (Lava Ultimate, 3M Espe) und cast gold (Degussa). Subcriitical loading
was performed using a chewing simulator. Chewing simulation was carried out with
1,200,000 cycles at a force of 50 N and additional 300.000 thermocycles (5°C/55°C).
Consequently the teeth were loaded in a universal testing machine until catastrophic
The statistical analysis was performed using the Windows program SPSS 15.0 (SPSS,
Chicago, USA). For the analysis I used the Kolmogorov-Smirnov-test, the Wilcoxon
matched-pairs-signed-ranks-test and the Kruskal-Wallis-test.
The highest fracture resistance was measured for restorations with cast gold partial crowns
and in the control group (p<0.05). The lowest results were measured with IPS Empress
inlays, IPS Empress partial crowns, e.max CAD inlays and Celtra Duo inlays. It was
remarkable that the values of the overlay restorations were significantly higher than the
inlay restorations (p<0.05). Only the IPS Empress inlays and IPS Empress partial crowns
showed no significant difference (p<0.05).
The results of this study exhibited significant differences between the fracture resistance in
inlay and partial crown restorations. Except for IPS Empress restorations, partial crowns
showed higher results than inlays. The highest fracture strengths were measured for gold
partial crowns and the control group, respectively.
Based on the current results, the post-endodontic restoration with partial crowns is the
best way for post-endodontic restoration when it comes to fracture resistance.
By comparing the groups, the significantly higher values of gold partial crowns and the
control group are noticeable. All in all the present results corresponded to the empirical