Novel non-invasive reinforcement of MOD cavities on endodontically treated teeth

Abstract

A B S T R A C TObjectives: To evaluate the biomechanical influence of reconnecting the buccal and lingual walls of endodontically treated lower molar with a large MOD cavity. Methods: 3D models were created from a micro-CT scan of an extracted intact lower human molar. Finite element analysis was then used to compare the stress distribution and displacement of the structures between different models: Unrestored MOD on ETT (Unrest), MOD on ETT restored with composite resin (Norm), MOD on ETT reinforced with a non-invasive ring (Ring) and intact tooth as the control (Int).Results: This study showed that the Unrest model presented the highest stress values at the cervical level. The non-invasive Ring model showed the lowest stress values at the cervical level, and the lowest deflection of the cusps. Conclusions: Mechanically reconnecting the remaining tooth structures has a direct positive effect on stress distribution and deformation of the remaining structures. Clinical relevance: Reinforcing ETT in a non-invasive direct approach is efficient in terms of preserving sound tooth structures, reducing the time of treatment and eliminating the laboratory steps required to create the restorations.

Fracture behaviour of MOD restorations reinforced by various fibre-reinforced techniques – An in vitro study

“…Connecting the remaining opposing cavity walls can be also accomplished circumferentially covering the rebuilt mesial and/or distal walls, a technique called "wallpapering" by Deliperi and colleagues (Deliperi et al, 2017). So far, to use of FRC materials to circumferencially connect the walls of MOD cavities was only attempted by Daher et al (2016), but they performed this externally, around the coronal part of the teeth. In our study, when applied circumferentially, there was no difference between the fibre glass net and polyethylene fibres.…”

Fracture strength of non-invasively reinforced MOD cavities on endodontically treated teeth

“…Mandibular molars were chosen for this test to be in agreement with the first study that first described this technique [14]. In that mentioned study, the authors propose two possible configurations of placing the fiber-reinforced strip: in a regular ring shape surrounding the crown or in a modified ring with the fibers crossing in the middle of the cavity in an "X" shape.…”

“…Cuspal deflection was shown to induce micro-cracks due to cyclic bending loads and the limited elasticity of dental hard tissues [23]. The FEA study that first evaluated the effect of non-invasively reinforcing MOD cavities with a fiber-reinforced strip [14], showed a reduction of cuspal deflection. It also showed that the stress values in the cervical area of ring-reinforced teeth were lower compared to normal restorations, by redirecting that stress into the fiber bundle.…”

“…With multiple studies showing that removal of even small volumes of hard tissue is directly linked to reduced stiffness and reduced fracture resistance [11][12][13], non-invasive approaches should be favored. A recently published finite element analysis (FEA) study [14] has proposed the use of fiber-reinforced "rings" to wrap around the occlusal part of remaining buccal and lingual walls of large mesiooccluso-distal (MOD) cavities on ETT. The rationale was to limit the deflection of the cusps through a noninvasive method.…”

Effect of Different Fiber Reinforcement Strategies on the Fracture Strength of Composite Resin Restored Endodontically Treated Premolars

“…Recently, the results of another FEA study demonstrated that reconnecting buccal and lingual walls of an endodontically treated lower molars with a 2 mm wide FRC band modeled as ring around the middle of the crown has a positive effect on stress distribution, reduces stress concentration at the cavity wall-restorative material interface and enhances fracture resistance [35].…”