Effect of Biologically Oriented Preparation Technique on the Stress Concentration of Endodontically Treated Upper Central Incisor Restored with Zirconia Crown: 3D-FEA

Abstract

The aim of this study was to evaluate the effect of biologically oriented preparation technique on the stress concentration of endodontically treated upper central incisors restored with zirconia crown (yttria-stabilized zirconia polycrystalline ceramic) through finite element analysis (FEA). Four models of maxillary central incisors containing enamel, dentin, periodontal ligament, cortical and medullary bone were created in CAD. Each model received a polymeric core-build up with nanofilled dental resin composite. The evaluated models were SM—preparation in shoulder 90°; CM—chamfer preparation; BOPT—biologically oriented preparation technique and BOPTB—BOPT preparation 1 mm below the cement-enamel junction. All models received zirconia crowns (5Y-TZP), fiberglass post and 1 mm ferrule. The models were imported into the analysis software with parameters for mechanical structural testing using the maximum principal stress and the tensile strength as the analysis criteria. Then, load of 150 N was applied at the cingulum with 45° slope to the long axis of the tooth, with the fixed base for each model. The type of marginal preparation affected the stresses concentration in endodontically treated teeth and in the zirconia crown margin. Considering the stress magnitude only, BOPT is a viable option for anterior monolithic zirconia crowns; however, with the highest stress magnitude at the restoration margin.

Comparative Evaluation of Stress Acting on Abutment, Bone, and Connector of Different Designs of Acid-Etched Resin-Bonded Fixed Partial Dentures: Finite Element Analysis

“…A long-term follow-up indicated that abutment teeth mobility is one of the decisive prognostic factors for the success of RBFPDs ( Farshad et al, 2013 ). Furthermore, it was reported that an RBFPD without any retentive preparation design failed significantly at a higher rate ( Sichi et al, 2021 ). Saad et al suggested that the addition of retentive grooves made a statistically significant difference in resistance to debonding forces ( Saad et al, 1995 ).…”

Effect of Antirotational Two-Piece Titanium Base on the Vertical Misfit, Fatigue Behavior, Stress Concentration, and Fracture Load of Implant-Supported Zirconia Crowns

“…The issue of vertical misfit has long been recognized as a significant concern in implant dentistry. Vertical misfit refers to the discrepancy between the implant fixture and the abutment, which can lead to complications such as peri-implant bone loss, implant failure, and compromised esthetics [ 33 , 34 , 35 ]. The prosthetic–abutment vertical misfit in clinical settings usually ranges from 50 to 160 μm in implant-supported prostheses manufactured using the casting technique [ 36 ].…”

Mechanical behavior of different machinable ceramic crowns using vertical and horizontal preparations: an in-vitro study

“…However, the mean fracture loads for the VP (1432 + 809 N) although it was less than HP, it still exceeded the maximum chewing forces reported in the literature in the posterior region (300 -850 N) [23]. Accordingly, this means that vertical preparation design could be an alternative to the less conservative chamfer and shoulder margin designs and can be used in certain clinical situations, such as severely damaged teeth, endodontically treated teeth, periodontally affected teeth and implant supported restorations where margin needs to be placed deep subgingival following the BOPT concept [24,25]. O u r r e s u l t s a g r e e d w i t h s e v e r a l studies [19,[26][27][28], which reported that a 1 mm deep shoulder finishing line with a rounded internal line angle has better fracture strength for all ceramic crowns and provide more even stress distribution than other preparation design.…”