Fatigue survival of endodontically treated teeth restored with different fiber-reinforced composite resin post strategies versus universal 2-piece fiber post system: An in vitro study

Marcela Moreira Penteado, DDS, MS, PhD, a Guilherme Schmitt de Andrade, DDS, MS, b Rodrigo Máximo Araujo, DDS, MS, PhD, c Alexandre Luiz Souto Borges, DDS, MS, PhD, d Luiz Felipe Valandro, DDS, MS, PhD, e Gabriel Kalil Rocha Pereira, DDS, MS, PhD, f and João Maurício Ferraz da Silva, DDS, MS, PhDg g

Objective: To assess the fatigue resistance andstress distribution of endodontically treated teeth without a splint that wererestored with posts from various systems and the recently introduced two-pieceuniversal post. The null hypothesis predicted that no differences in fatiguebehavior or stress distribution would be found between the three systems.
Clinical Implications: Because one of thepurposes of the Splendor® Universal post is to replace the anatomized posttechnique, it is critical that the fatigue resistance and stress distributionare superior in the Splendor® Universal when compared to this other technique. 
Figure 5 shows that post displacement causedcracks and fractures along the entire root cementation line, with fragmentsremaining in both the post and the dentin. Crown loss implied core inadequacy, even if itwas not clinically detected. The Splendor® Universal group showed no damage tothe post adaptation space, demonstrating that adaptation associated withadhesive adhesion was effective for the post, but not enough to preventfractures in the cervical region.
The finite element analysis data revealed thatthe Splendor® Universal system had a reduced stress area on the dentin (Fig.6). The Splendor® Universal system showed the highest number of areas of stressconcentration in the cement line (Fig. 8).
Discussion:
‍
• The Splendor®Universal system demonstrated the greatest resistance to load failure andcyclic fatigue, as well as a smaller stress area in the dentin and core-dentincement line.
‍
• When compared to theother posts, the Splendor® Universal system withstood a greater number ofcycles and magnitude of load before failing due to cyclic fatigue.
‍
• When all systems were subjected to a higherload, core and crown fractures occurred, but the Splendor® Universal systemspecimens withstood more cycles before failing.
‍
• Biomechanical reasons for the improvedperformance of the UNI system included the likelihood of stress being directedthrough the sleeve and internal cement line.
‍
• No specimen, regardless of post type, exhibiteda catastrophic fracture. The concept of devices with a modulus of elasticityclose to the dentin remains a viable option for this type of restoration.

‍Conclusions:
‍
Based on the resultsof this in vitro study, it was concluded that
‍
1. The universal posthad similar fatigue behavior and stress distribution to well-adapted andexecuted posts, and it outperformed the anatomized fiberglass post withcomposite resin.
‍
2. Post detachment wasthe most common failure mode in the evaluated post systems.