Related Experiment Videos
Over-refractory casting technique as an alternative to one-piece multi-unit fixed partial denture frameworks
Giovani de Oliveira Correa1, Guilherme Elias Pessanha Henriques, Marcelo Ferraz Mesquita
1Department of Restorative Dentistry, Piracicaba School of Dentistry, State University of Campinas, UNICAMP, Sao Paulo, Brazil.
The Journal of Prosthetic Dentistry
|March 18, 2006
Summary
The over-refractory technique (ORT) significantly reduces marginal discrepancies in multi-unit fixed partial denture (FPD) frameworks compared to the conventional technique (CT). This improved fit is crucial for durable dental restorations.
Area of Science:
- Dental Materials Science
- Prosthodontics
- Biomaterials Engineering
Background:
- Soldering is used for multi-unit fixed partial denture (FPD) frameworks, but can cause distortion.
- Evaluating alternative casting techniques is essential for improving FPD framework fit.
Purpose of the Study:
- To compare the marginal fit of 1-piece-casting FPD frameworks using the conventional technique (CT) and the over-refractory technique (ORT).
- To assess the performance of CT and ORT with commercially pure titanium (CP Ti), titanium-aluminum-vanadium (Ti-6Al-4V), and nickel-chromium (Ni-Cr) alloys.
Main Methods:
- A 5-unit FPD model was used to create 60 working casts.
- Frameworks were fabricated using CT (wax patterns removed before investing) and ORT (wax patterns on refractory casts).
- Marginal discrepancies were measured using a traveling microscope and analyzed with ANOVA and Tukey HSD tests.
Main Results:
- ORT frameworks exhibited significantly lower marginal discrepancies (82.8-64.4 µm) than CT frameworks (106.3-75.7 µm) across all tested alloys (P < .05).
- Marginal discrepancies varied significantly among alloys, with Ti-6Al-4V showing the least and CP Ti showing the most discrepancy for both techniques.
Conclusions:
- The over-refractory technique (ORT) significantly improves the marginal fit of multi-unit FPD frameworks compared to the conventional technique (CT).
- ORT offers a superior method for fabricating dimensionally stable FPD frameworks, enhancing prosthetic success.