Accuracy of cast posts and cores using a new investigative method

Area of Science:

• Dental Materials Science
• Prosthodontics
• Biomaterials Engineering

Background:

• Fabrication of cast posts and cores (CPCs) typically involves direct or indirect techniques.
• Existing research lacks a clear consensus on the comparative accuracy of these CPC fabrication methods.
• Accurate fit of CPCs is critical for long-term restoration success in endodontically treated teeth.

Purpose of the Study:

• To quantitatively compare the accuracy and intimacy of fit between direct and indirect cast post and core fabrication techniques.
• To introduce and utilize a novel method for evaluating CPC fit using silicone impression material and precision weighing.
• To provide evidence-based guidance for clinicians selecting CPC fabrication methods for posterior teeth.

Main Methods:

• Nine endodontically treated human premolars were used to fabricate 18 cast posts and cores (CPCs) via direct and indirect methods, cast in high noble gold.
• Silicone impression material was used to record the space between the root canal and the fabricated CPC.
• The accuracy of fit was determined by weighing the residual silicone material using an electronic precision balance, with statistical analysis performed using a Student t-test at a 90% confidence interval.

Main Results:

• The mean weight of silicone material for the direct method was 10.3 ± 2.6 mg, indicating a less precise fit.
• The mean weight of silicone material for the indirect method was significantly lower at 7.4 ± 2.3 mg (P = 0.006), suggesting superior accuracy.
• Clinical examination by two independent practitioners corroborated the quantitative findings, with the indirect method yielding better-fitting CPCs.

Conclusions:

• The indirect fabrication technique for cast posts and cores results in significantly higher accuracy and a more intimate fit compared to the direct method.
• The indirect method is recommended for dental practitioners, particularly when fabricating multiple posterior CPCs or in cases with limited interocclusal space.
• This study provides valuable quantitative data supporting the clinical preference for the indirect method in specific restorative scenarios.