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Retention properties of a split-shaft threaded post: cut at different apical lengths
B I Cohen1, S Condos, B L Musikant
1Essential Dental Laboratories, South Hackensack, N.J.
The Journal of Prosthetic Dentistry
|December 1, 1992
Summary
Shortening dental posts can affect retention. For No. 1 Flexi-Posts, apical reductions up to 5mm showed no difference, but 4mm increased retention. For No. 2 Flexi-Posts, reductions up to 4mm were comparable, while 5mm significantly reduced retention.
Area of Science:
- Restorative Dentistry
- Dental Materials Science
Background:
- Post retention is crucial for endodontically treated teeth.
- Customizing post length is a common clinical practice.
Purpose of the Study:
- To compare the retention of shortened Flexi-Posts (No. 1 and No. 2) with full-length controls.
- To evaluate the effect of varying apical reductions (1-5 mm) on post retention.
Main Methods:
- Ten groups of Flexi-Post restorations (No. 1 and No. 2) were created with apical reductions of 1-5 mm.
- Retention values were measured in pounds using a universal testing machine.
- Statistical analysis involved ANOVA with a Tukey-Student range test.
Main Results:
- No. 1 Flexi-Posts: Reductions of 1, 2, 3, and 5 mm showed no statistical difference from full-length controls; 4 mm resulted in statistically greater retention.
- No. 2 Flexi-Posts: Reductions of 1-4 mm showed no statistical difference from full-length controls; 5 mm resulted in significantly less retention.
Conclusions:
- Apical shortening of Flexi-Posts can maintain or enhance retention depending on the post size and degree of reduction.
- A 4 mm apical reduction may improve retention for No. 1 Flexi-Posts.
- Excessive apical shortening (5 mm) can compromise retention, particularly for No. 2 Flexi-Posts.