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A clinical evaluation of fixed partial denture impressions
Nachum Samet1, Michal Shohat, Alon Livny
1Harvard School of Dental Medicine, Boston, MA, USA.
The Journal of Prosthetic Dentistry
|July 28, 2005
Summary
Most dental impressions for fixed partial dentures (FPD) contain errors. Polyether impressions showed the highest error rates, indicating a need for improved quality control in dental impression techniques.
Area of Science:
- Dental Materials Science
- Prosthodontics
- Clinical Dentistry
Background:
- Accurate dental impressions of hard and soft tissues are crucial for laboratory fabrication.
- Clinicians must routinely evaluate impression quality before laboratory submission.
Purpose of the Study:
- To evaluate the quality of impressions submitted for fixed partial denture (FPD) fabrication.
- To determine the frequency of clinically detectable errors in dental impressions.
- To analyze factors correlated with impression errors.
Main Methods:
- 193 FPD impressions were assessed by calibrated examiners across 11 dental laboratories.
- Impression techniques, materials, tray types, and prepared units were recorded.
- Specific errors including voids, tears, polymerization defects, and material issues were documented.
Main Results:
- 89.1% of evaluated impressions exhibited at least one observable error.
- Material type significantly correlated with voids/tears at the finish line (Rv = 0.17, P < .025).
- Material type also correlated with polymerization problems (Rv = 0.223, P < .004).
Conclusions:
- Polyether impressions demonstrated the highest frequency of detectable errors.
- Condensation-type silicones also showed a high error rate.
- The prevalence of errors in impressions for FPD fabrication is a significant concern.