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RelyX™ Fiber Post FAQs

Frequently Asked Questions



Posts | Drills | Comparative | Cementation | Core Build-up | General



What is our RelyX™ Fiber Post made of?

RelyX Fiber Post is made of glass fibers which are embedded in a cured epoxy-resin matrix containing zirconia filler which aids in the radiopacity of the post. The post contains 60 - 70% (by weight) of glass fibers. The fibers are oriented longitudinally in the post and are dispersed homogeneously within the cross section of the post. The adhesion of the epoxy-resin to the glass fibers is a key point for excellent fatigue properties of the post.

The composition of the RelyX Fiber Post provides an elastic modulus similar to dentin, allowing functional stresses to be dissipated rather than concentrated in the root. Therefore the likelihood or potential for root fractures is reduced. The outer surface of RelyX Fiber Posts has a micropourous surface which aids in good mechanical retention of RelyX Unicem cement which aids in the adhesive strength between the post and the cement.

What is the shape of the RelyX™ fiber post?

RelyX Fiber Posts have a tapered shape which is similar to the anatomical form of the root. The posts are parallel walled (cylindrical) at the coronal end and conical at the apical end.

What is the incidence of root fractures with glass fiber posts?

The various long term studies are sometimes hard to compare and show a wide range of results. In some studies metal post failure rates with a high share of root fractures range between 2-8% per year (e.g. Mentink; Torbjorner).

Glass fiber post failure rates were reported to be between 1.6-3.2%, with none or very minor incidents of root fracture among these general failures. (Ferrari).

It is important to know, that the failure modes are very different between metal and fiber posts.

Teeth restored with fiber posts have fewer failures that are non-restorable, while stiff material such as metal posts leads more commonly to non-restorable, catastrophic failures with loss of tooth or deep root fracture (Akkayan; for review article see R.S. Schwartz, J. Endo.; 30 (5) 2004; p. 289).

Do glass fiber posts corrode like metal post?

No. There is no corrosion of the fiber posts. Therefore, there is no risk of an allergic reaction due to metal.

Is it easier to remove a fiber post than metal?

Removal of an endodontic post requires extreme caution whether the post is metal or glass fiber reinforced. Use an x-ray to visualize the drilling depth and position of the post and use an x-ray during the actual post removal procedure.

In most cases a fiber post is far easier to remove than a metal post. Removal of a metal post can be difficult in the following situations:

  1. Long post cemented with resin modified glass ionomer or resin cement
  2. Severe trauma to tooth an metal post such that top of metal post sheared off

Some fiber post manufacturers offer a special removal kit, which, may not be necessary in the experts' view.

A typical procedure would involve the following steps:

  • Drill an orientation hole into the fiber post using a fine ball-shaped diamond drill (e.g. 15,000 rpm).
  • Drill into the prepared hole with the RelyX™ Fiber Post drill of the appropriate size for removal of all post and cement residues.
  • The post is now removed and the canal is ready for endodontic retreatment. Typically a new post will not be placed immediately after removal of the old post. The placement of a new post will depend on the endodontic retreatment and condition of the root canal.

Metal or zirconia ceramic posts cannot be disintegrated or removed in this way. If the cement does not give way easily, removal of these posts are extremely difficult and lead to additional loss of tooth structure, if not fracture.

How does the shape of our post benefit the post placement process?

The tapered shape is closer to the anatomical form of a root canal. This means the root canal preparation can be done in a conservative way, without excessive removal of root canal dentin. More tooth reduction means increase weakening of the tooth.

Do the colors and sizes of our posts match Coltene Whaledent® ParaPost® or any other standard sizing?

ISO standards recommend that the smallest post in a set be yellow and the largest post be blue. Depending on the amount of offerings additional post colors can be added in between yellow and blue.

The Fiber Post sizes/colors are similar, but do not exactly match other post manufacturers.

What pre-treatment do fiber posts need, when cemented with RelyX Unicem cement?

RelyX Fiber Post does not require pre-treatment when cemented with RelyX Unicem cement. Tests showed that applying a ceramic primer (3M™ ESPE™ RelyX™ Ceramic Primer) or use of bonding agents do not increase the bond strength to the post significantly. The bond strength between RelyX Unicem cement and RelyX Fiber Post is very high, actually much higher than the typical cement-dentin bond strength. Therefore any attempt to increase the bond strength of the cement-post interface should be clinically not relevant.

If RelyX Unicem cement is used in combination with glass or quartz fiber posts other than RelyX Fiber Post follow the pre-treatment recommendation of the manufacturer of the fiber post. If no pre-treatment is described we recommend the use of a silane ceramic primer on the post after cleaning with alcohol solution.

Are the RelyX Fiber Posts coated with anything?

The fiber posts are not coated with any type material.

In the RelyX Fiber Post Technical Product Profile it states that the radiopacity of the number 3 post is 200% Al. What does this mean?

A radiopacity of 200% Al (aluminum) is the same as saying the radiopacity of the number 3 post is 2. It is as radiopaque as 2 mm of aluminum (Al).

Do our fiber posts and drills correlate with endodontic reamers and drills?

Currently there is no correlation data available.

Which post would a dentist use in a situation whereby the endodontist has pre-drilled the canal for the dentists? The predrilled canal was not done with our drills.

According to the instructions for use it is recommended to select the post size and the matching drill as indicated by X-rays and according to the diameter of the prepared root canal.

Other posts are measured in inches, what is the conversion of our fiber posts from millimeters (mm) to inches?

  Millimeters (mm) Inches (in.)
Fiber Posts Length 20 0.79
Diameter Yellow 1.3 0.051
Diameter Red 1.6 0.063
Diameter Blue 1.9 0.075

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