The restoration of the endodontically treated tooth is a significant challenge to the restorative dentist. In the past cast metal post and cores and prefabricated metal posts were placed with cements that only created a frictional fit between post and tooth. These posts offered no structural reinforcement to the teeth they were helping restore. Also these materials would sometimes gray out the tooth and shine through all ceramic restorations. With today's materials, an esthetic bonded post and core can be placed that reinforces the endodontically treated tooth.
To keep the structure of the tooth as strong as possible, an engineering approach to rebuilding endodontically treated teeth should be taken. These principles were described by Dr. Jack Nicholls.
Nicholls JI. An engineering approach to the rebuilding of endodontically treated teeth, J Clin Dent, 1:41-44, 1995
With this in mind, a number of pioneers in adhesive dentistry when restoring the endodontically treated tooth including Hornbrook, Karna, Bartel, and Antonson, started using fiber reinforcement ribbon, Ribbond®, to structurally reinforce teeth.
Formed in a conformable state
Retentive and antirotational (increase in each increases the retention)
This patient had an unesthetic porcelain-metal crown with a large metal post that demonstrates graying out at the cervical margin. Although the crown color is acceptable to the patient, the gingival darkness was unacceptable and exaggerated by the patients high smile lip line. She wanted to replace the crown with a better looking front tooth.
Clinical case: Dr. David Hornbrook
The crown was removed. The entire tooth was discolored. Any residual eugenol from the root canal sealer was removed by cleaning the canal with a 75% alcohol. Non-vital bleaching of the central incisor was done. Before doing the non-vital bleach the root canal was sealed with a glass ionomer cement to eliminate leakage of the bleaching material into the root canal. After bleaching, the tooth was now ready to be esthetically restored.
The decision to use a the color neutral, esthetic Ribbond post and core technique was based upon the amount of coronal tooth remaining, access and flare of canal, occlusion and final restoration being an all-ceramic crown.
The post length was created to be equal to the final height of the coronal preparation.
Technique for placement of Ribbond Reinforcement Ribbon into the canal. Select either 2 mm width or 3 mm for wide canals, use at least two fiber ribbons adapted into canal, wet the Ribbond with adhesive resin and the root canal is treated with an adhesive procedure.
The polyethylene fibers of Ribbond are plasma treated to allow the dental resin to bond to its surface.
Ribbond reinforcement ribbon being wetted with unfilled adhesive resin
The central incisor was prepared for an all-ceramic crown, impressed and sent to the laboratory. The Ribbond extending from the incisal edge can be covered with a flowable composite resin before making the impression.
Note: A Ribbond post and core is designed to be retentive. A ferrule or should preparation extending at least 1.5 mm on to the tooth is required to support the crown.
Clinical case: Dr. David Hornbrook
For this patient, his maxillary incisor had a traumatic fracture and was endodontically treated. Note large radicular space due to immature tooth, open apex.
Clinical case: Bill Bartel, DDS
The tooth was endodontically treated with apexification using calcium hydroxide and then filled with gutta percha. Note the large canal space and thinned interior structure of the tooth.
The tooth was restored as previously described- the root canal was etched, an adhesive placed and a hybrid dual cure composite placed in canal. For this case two pieces of Ribbond 3 mm were placed into resin using a Ribbond Endodontic instrument.
of Ribbond 3 mm
placed into the canal
Because the patient was a young teenager the final restoration was a Class IV composite resin. The Ribbond shows up on the x-ray as being embedded into the composite resin.
Clinical case: Dr. David Hornbrook.
Recommended by many well-known lecturers, the Ribbond endodontic post and core technique minimizes the chance for root fracture and has the following advantages.
Furthermore, because Ribbond's translucent fibers take on the color characteristics of the composite it allows for the natural transmission of light through teeth and crowns. This provides an exceptionally esthetic result.
Other than the normal endodontic treatment, further shaping is not required to accommodate the size and shape of a preformed post. The following is a brief description of the procedure. The Ribbond instruction manual, included with a purchase, clearly describes this technique in full detail.
Prepare the canal for normal dentin bonding. Inject a dual cured moderately filled composite such as a luting composite into the canal. Use the special Ribbond post and core instrument to carry the wetted Ribbond through the luting composite in the canal to the apical end of the canal.
Apply composite to the protruding Ribbond ends and roughly form them into the shape of the core and cure. Build up the core with composite, cure it and shape it
Note: Ribbond fibers are not radio opaque.