Related Experiment Videos
Phase transformations in a leucite-reinforced pressable dental ceramic.
I L Denry1, J A Holloway, H O Colijn
1College of Dentistry, Section of Restorative Dentistry, Prosthodontics, and Endodontics, Ohio State University, Columbus 43210-1241, USA. denry.1@osu.edu
Journal of Biomedical Materials Research
|February 24, 2001
Summary
Sanidine formation in pressable dental ceramic requires specific high temperatures and long durations, conditions not met during typical veneering processes. This study clarifies the phase transformations in leucite-reinforced ceramics.
Area of Science:
- Materials Science
- Dental Ceramics
- Crystallography
Background:
- Leucite-reinforced ceramics are widely used in dentistry.
- Understanding phase transformations is crucial for material stability and performance.
- Sanidine formation conditions in pressable dental ceramics are not fully elucidated.
Purpose of the Study:
- To determine the specific heat treatment conditions (temperature and time) for sanidine formation in a pressable dental ceramic (OPC).
- To investigate the crystalline phases present in OPC after various heat treatments.
- To assess the clinical relevance of sanidine formation during dental ceramic processing.
Main Methods:
- Ceramic discs were subjected to heat treatments ranging from 700°C to 1100°C for 10 minutes to 24 hours.
- X-ray diffraction (XRD) was used to identify crystalline phases.
- Scanning electron microscopy (SEM) was employed to examine the microstructure.
Main Results:
- Sanidine was the sole crystalline phase after heat treatment at 900°C for 24 hours.
- Mixed phases of tetragonal leucite and sanidine were observed at 900°C for 12 hours and 800°C for 24 hours.
- Tetragonal leucite was dominant at lower temperatures and shorter durations, including typical veneering conditions.
Conclusions:
- Sanidine formation in this pressable dental ceramic necessitates prolonged exposure to high temperatures (e.g., 900°C for 24 hours).
- The temperatures and times typically used for staining or veneering leucite-reinforced ceramics are insufficient for sanidine formation.
- The study indicates that sanidine is unlikely to form during routine clinical processing of this material.