Journal of Isfahan Dental School

The Effect of Preparing the Endocrown with and Without Rounding the Internal Angle on the Distribution of Forces Using Finite Element Analysis

Document Type : مقاله‌های پژوهشی

Author

Associate Professor, Dental Material Research Center, Department of Prosthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran

Abstract

Introduction: The design and preparation of dental restorations significantly affect the clinical success of endocrowns. However, there is limited information regarding the biomechanical impact of the geometry and shape of endocrown preparations. Therefore, this study aimed to investigate the preparation of endocrowns with a butt joint design, with and without rounded internal angles, on the distribution of forces using finite element analysis (FEA).
Materials and Methods: To evaluate force distribution, two three-dimensional finite element (FE) models were created: one with a butt joint finish line and rounded internal angles (Model 1) and one without rounded angles (Model 2). By inputting these data into software and applying loading conditions, outputs including all stresses and displacements were obtained. In both 3D models, the amount of remaining tissue and the type of restorative material used were identical; lithium disilicate was selected as the restorative material in both models. Tests for elastic strain, stress, and overall deformation were conducted on the models using this software.
Results: The deformation in Model 1 was measured at 5.27 micrometers, while in Model 2, it was 6.88 micrometers. The stress levels were 46.6 megapascals in Model 1 and 127.87 megapascals in Model 2. The strain values were 0.0014475 for Model 1 and 0.004171 for Model 2, revealing a significant difference in biomechanical behavior between the two preparation types.
Conclusion: The geometry and shape of the preparation influence the biomechanical behavior of restorations. The endocrown preparations of Model 1 and Model 2 demonstrate different biomechanical behaviors, with Model 1 being more efficient, producing stress levels approximately one-third lower under equal force conditions.
Keywords: Dental crowns; Biomechanics; Finite element analysis.

1. Hasan I, Frentzen M, Utz KH, Hoyer D, Langenbach A, Bourauel C. Finite element analysis of adhesive endo-crowns of molars at different height levels of buccally applied load. J Dent Biomech 2012; 3: 1758736012455421.
2. Kassis C, Khoury P, Mehanna CZ, Baba NZ, Bou Chebel F, Daou M, et al. Effect of inlays, onlays and endocrown cavity design preparation on fracture resistance and fracture mode of endodontically treated teeth: an in vitro study. J Prosthodont 2021; 30(7): 625–31.
3. Botto B, Ernesto, Baron, Rosario, Luis J. Endocrowns: A retrospective patient series study, in an 8-to-19-year period. Odontoestomatologia 2016; 18(28): 45-56
4. Carlos RB, Nainan MT, Pradhan S, Sharma R, Benjamin S, Rose R. Case report restoration of endodontically treated molars using all ceramic endocrowns. Case reports in dentistry. Case Rep Dent 2013; 2013: 210763.
5. Ertuk BK, Yigit D, Saridag S, Avcu E. Fracture strengths of endocrown restorations fabricated with different preparation depths and CAD/CAM materials. Dent Mater J 2018; 37(2): 256-65
6. Sedrez-Porto JA, de Oliveira da Rosa WL, da Silva AF, Aldrighi ME, Pereira-Cenci T. Endocrown Restorations: A Systematic Review and Meta-Analysis. J Dent 2016; 52: 8-14.
7. Rocca GT, Rizcalla N, Krejci I. Fiber-reinforced resin coating for endocrown preparations: a technical report. Oper Dent 2013; 38(3): 242-8.
8. Shah RJ, Lagdive S, Verma V, Shah S, Saini S. Rehabilitating endodontically treated mandibular molar having inadequate coronal length with “Endocrown” - a neoteric clinical approach. IOSR Journal of Dental and Medical Sciences 2017; 16(1): 29-33.
9. Amal S, Nair MG, Sreeja J, Babu A, Ajas A. Endocrown - An Overlooked Alternative. Arch of Dent and Med Res 2016; 2(1): 34-38.
10. Tribst JP, Dal Piva AM, Madruga CF, Valera MC, Borges AL, Bresciani E, de Melo RM. Endocrown restorations: Influence of dental remnant and restorative material on stress distribution. Dent Mater 2018; 34(10): 1466-73.
11. Hayes A, Duvall N, Wajdowicz M, et al. Effect of endocrown pulp chamber extension depth on molar fracture resistance. Oper Dent 2017; 42(3): 327–34.
12. Dartora NR, de Conto Ferreira MB, Moris ICM, Brazao EH, et al. Effect of intracoronal depth of teeth restored with endocrowns on fracture resistance: in vitro and 3-dimensional finite element analysis. J Endod 2018; 44(7): 1179-85.
13. Zhu J, Wang D, Rong Q, et al. Effect of central retainer shape and abduction angle during preparation of teeth on dentin and cement layer stress distributions in endocrown-restored mandibular molars. Dent Mater J 2020; 39(3):464-70.
14. Einhorn M, DuVall N, Wajdowicz M, et al. Preparation ferrule design effect on endocrown failure resistance. J Prosthodont 2019; 28(1): e237-e242.
15. Farah JW, Dennison JB, Powers JM. Effects of design on stress distribution of intracoronal gold restorations. T J Am Dent Assoc 1977; 94(6): 1151-4.
16. Fratila A, Oleksik V, Boitor C, Pascu A, Pirvu B. Numerical study about the strain analysis and the marginal design of dental indirect restorations. Romanian Biotechnological Letters 2012; 17(4): 7474-82.
17. Gaintantzopoulou MD, El-Damanhoury HM. Effect of preparation depth on the marginal and internal adaptation of computer-aided design/computer-assisted manufacture endocrowns Oper Dent 2016; 41(6): 607-16.
18. Darwish HA, Morsi TS, El Dimeery AG. Internal fit of lithium disilicate and resin nano-ceramic endocrowns with different preparation designs. Future Dental Journal 2017; 3(2): 67–72
19. Ghoul WE, Özcan M, Tribst JPM, Salameh Z. Fracture resistance, failure mode and stress concentration in a modified endocrown design. Biomater Investig Dent 2020; 7(1): 110–9.
20. Kelly JR. Dental ceramics: what is this stuff anyway? J Am Dent Assoc 2008; 139(Suppl): 4S–7S.
21. 5. Biacchi GR, Basting RT. Comparison of fracture strength of endocrowns and glass fiber post-retained conventional crowns. Oper Dent 2012; 37(2): 130–6.
22. Pedrollo Lise D, van Ende A, De Munck J, Umeda Suzuki TY, Cardoso Vieira LC, van Meerbeek B. Biomechanical behavior of endodontically treated premolars using diferent preparation designs and CAD/CAM materials. J Dent 2017; 59: 54–61.
Journal of Isfahan Dental School
Volume 20, Issue 3 - Serial Number 3
October 2024
Pages 231-238