Abstract
OBJECTIVES: To determine the minimum thickness required for a monolithic hybrid ceramic crown on different substrates (soft vs stiff) used in posterior dentition for bruxism.
METHODS: 80 polymer-infiltrated ceramic networks Vita Enamic (PICN VE) disc specimens with four different occlusal thicknesses (0.8, 1.2, 1.6 and 2.0 mm), were produced using a computer-aided design/manufacturing system, and cemented on a stiff (zirconia) or soft (polyamide) substrate of 4-mm thickness. The ten specimens, in soft or stiff groups, were subjected to compressive loading by a MTS machine until fracture or maximum load (4500 N) was reached. The unbroken specimens were examined using optical coherence tomography. Eight axisymmetric finite element models and eight 3D models comprising the four different occlusal thicknesses and two substrates under different vertical loads and sliding movements were constructed. The maximum principal stress was selected to evaluate the stress distribution in this study.
RESULTS: The fracture resistance of the specimens was significantly different between the two substrates (P < 0.001). Fracture resistance was positively associated with specimen thickness (r = 0.597 and 0.896 for the soft and stiff substrate respectively). Specimens on the soft substrate had lower fracture loads, whilst cone cracks were observed in unbroken samples on different soft/stiff substrate prior to final fracture. The finite element analysis confirmed that samples on the stiff substrate had lower maximum principal stress values than those on the soft substrate. For the maximum principal stress not to exceed the flexural strength of PICN VE, a stiff substrate and minimum thickness of 2.0 mm are required for the prostheses.
SIGNIFICANCE: A minimum 2.0 mm thick, stiff substrate was needed for bruxism as shown by the effect of high/large chewing force on the posterior dentition of monolithic PICN VE crowns.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 44-56 |
| Number of pages | 13 |
| Journal | Dental Materials |
| Volume | 38 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 2022 |
Bibliographical note
Funding Information:The authors would like to acknowledge the Minnesota Supercomputer Institute (MSI), University of Minnesota, for the provision of finite element software. We would also like to express our sincere gratitude to the MDRCBB and its staff for supporting and hosting this work. The authors gratefully acknowledge the support of the Science Park Bureau, Ministry of Science and Technology (MOST 108?2314-B-037?018), Taiwan, ROC, and KMUH Research Project (KMUH108?8G04, KMUH108?8R68), Taiwan, ROC.
Funding Information:
The authors would like to acknowledge the Minnesota Supercomputer Institute (MSI), University of Minnesota, for the provision of finite element software. We would also like to express our sincere gratitude to the MDRCBB and its staff for supporting and hosting this work. The authors gratefully acknowledge the support of the Science Park Bureau, Ministry of Science and Technology (MOST 108–2314-B-037–018 ), Taiwan, ROC, and KMUH Research Project ( KMUH108–8G04 , KMUH108–8R68 ), Taiwan, ROC.
Publisher Copyright:
© 2021 The Authors
Keywords
- Contact fracture
- Finite element analysis
- Monolithic hybrid ceramic
PubMed: MeSH publication types
- Journal Article
- Research Support, Non-U.S. Gov't