The effect of different geometric shapes and angles on the fracture strength of IPS e.max computer-aided designed ceramic onlays: An in vitro study
| Autor: | Bronwyn J. Lowe, Nicholas P. Chandler, Jonathan Chu, John M. Aarts, Vincent Bennani |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Universal testing machine
060101 anthropology Materials science medicine.medical_treatment 030206 dentistry 06 humanities and the arts Geometric shape occlusal reduction Ceramic onlay 03 medical and health sciences 0302 clinical medicine Flexural strength visual_art medicine visual_art.visual_art_medium Fracture (geology) In vitro study Cusp (anatomy) fracture strength 0601 history and archaeology Ceramic Original Research Article Composite material General Dentistry Reduction (orthopedic surgery) |
| Zdroj: | Journal of Conservative Dentistry : JCD |
| ISSN: | 0974-5203 0972-0707 |
| Popis: | Statement of Problem: The current ceramic onlay preparation techniques for cuspal areas involve the reduction of cusps following the cuspal anatomy and the removal of all sharp angulations. However, there is little research literature studying the effect of occlusal preparation angles. Furthermore, there is no recent literature on the effect of angulations on IPS e.max computer-aided designed (CAD) (e.max) ceramic onlays. Purpose: The purpose of this study is to investigate the effect of geometric cuspal angulation and different internal preparation angles on the fracture strength of e.max CAD ceramic onlays. Materials and Methods: Sharp (33° and 22°) and round (33° and 22°) preparations were tested, each group having 10 specimens. e.max ceramic onlays were milled, sintered, glazed, and then bonded onto geometric tooth models. Fracture strength was measured at the initial fracture with a universal testing machine. The load was applied laterally to the central fossa (2-point contact) and vertically to the cusp peak (1-point contact). Results: A reduced cuspal angulation of 22° resulted in a stronger ceramic onlay than a 33° angulation when laterally loaded (P = 0.001). The presence of sharp angles weakened the ceramic significantly for both the 22° preparation (P = 0.0013) and 33° preparation (P = 0.0304). Conclusion: This in vitro study found that preparation angles of 22° resulted in superior fracture strength during central fossa loading and that rounding the preparation resulted in significantly higher fracture strength when a cusp peak load was applied. When the cusp tip loading is applied, the preparation angle does not appear to influence the fracture strength. |
| Databáze: | OpenAIRE |
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