With the use of the latest generation of bonding agents, building up teeth with composite cores prior to restoring them with crowns has become very predictable. But even with these composite cores with greater bond strengths, the use of posts is still necessary at times to retain the core and prevent it from debonding. The use of prefabricated, fiber-reinforced posts has made the use of posts and cores efficient and reliable.
This article presents a case report in which a patient required immediate emergency treatment for a broken tooth.
|Figure 1. Tooth No. 28 was fractured below the gum line. Note lack of crown length for a ferrule.|
When the patient was eating at a restaurant over the weekend she fractured off her crown on tooth No. 29 below her gum line. The tooth had prior root canal therapy performed. After evaluating the digital radiograph (Sidexis Digital Radiography System) and examining the tooth, it was determined that the best treatment would be to place a post to retain a new core buildup, followed by surgical crown lengthening. Surgical crown lengthening would allow me to place a 2-mm ferrule around the tooth above my crown margin. The ferrule, along with a post to retain the core, would provide the most predictable situation to prevent future problems with her crown. Performing the crown lengthening first and then waiting for the tissue to heal before rebuilding the tooth with a post and core would have made it difficult to fabricate a temporary crown with any degree of retention. The patient did not want to go another day without a temporary crown in its place. So we decided to build up the tooth at the emergency appointment and place her temporary (Figure 1).
Because the patient had come to the office for an emergency appointment, we had limited time: we only had 30 minutes to restore the tooth with a temporary crown. My assistant started by placing the existing crown back on top of the root and tacking it in place by injecting composite interproximally and curing it for 5 seconds. This was just enough to hold it in place for an impression. She then took an impression of the quadrant with a triple tray and Status Blue impression material (Zenith). Status Blue is a polyvinyl impression material that is an alginate substitute. Because it is injected into the tray, it is much faster to capture an accurate impression than having to mix alginate first. After the impression was taken, the crown was easily removed.
|Figure 2. Electrosurgery being used to expose sufficient crown length.|
I began treating the tooth by anesthetizing the gum tissue surrounding the tooth with Citinest Plain followed by lidocaine. My first objective was to expose the remaining tooth structure fully. I used my electrosurge to remove 1 to 2 mm of tissue. I prefer to restore teeth with provisional restorations first when possible. I then perform surgical crown lengthening using the margin of the temporary as my guide as to where to place the new bone level (Figure 2).
|Figure 3. Decay is removed and opening to gutta-percha is exposed.||Figure 4. Smaller bur is “sunk” into the gutta-percha to desired depth.||Figure 5. Post space is created to allow for passive fit of the prefabricated fiberglass post.|
After the tooth was exposed, I removed any decay and staining. I use NSK electric handpieces (Brasseler/NSK). The high torque allows me to use very light pressure when prepping teeth. I used an NTI SC847-016KR diamond (Axis Dental) to remove the decay and roughen my prep (Figure 3).
After the decay was re-moved, I began to prepare the post space. From the radiograph, I determined I wanted to create a post space 6 mm deep. Achromat-HP Esthetic Fiber Post system (Axis Dental) includes 3 NTI endodontic drills to create the post space very quickly. I started with the Axis/NTI 1.20-mm drill and placed an endodontic file silicon stopper at 6 mm from the tip. I then used very light pressure and allowed the bur to “sink” slowly into the gutta-percha to the desired depth. I wiped the bur clean as it became clogged with gutta-percha (Figure 4).
Once the Axis/NTI 1.20-mm drill reached the desired depth, I used the 1.40-mm Axis/NTI drill or the 1.65-mm Axis/NTI drill, depending on what size Achromat-HP post I needed to create the post space. I used light pressure and an up-and-down motion as the bur created the post space. After the space was created, I tried in the post and adjusted the length so that it would not interfere with the occlusion. I wanted it at least 2 mm from the occluding tooth. I adjusted it by counting the notches sticking out of the post space. The Achromat-HP post cuts very easily and cleanly with a NTI D934-220 diamond disc (Axis Dental). I like to adjust the length of my post prior to isolating the tooth with a rubber dam. This allows me to have the patient bite into occlusion so I can visually check the amount of space between the top of the post and the occluding tooth (Figure 5).
|Figure 6. Prep is isolated and etched for bonding of the prefabricated post and core.||Figure 7. Primer/bonding agent applied to post space and prep.||Figure 8. Dual-cured core material is injected into the post space.|
I then isolated the tooth with a rubber dam. The tooth and post space were rinsed and dried, and then etched and primed. After I placed the dual-cure primer/bonding agent (Cabrio, Discus Dental) in the post space with an applicator, I used a paper point to remove any excess primer from the bottom of the post space. It takes very little excess primer to fill 1 mm of post space and prevent the post from seating fully to the desired depth. I did not cure the primer at this point, which would also prevent the post from seating fully (Figures 6 and 7).
The post was then rinsed, primed, and placed where it would not be touched. It was still secured with the cotton forceps I used to try in the post and remove it from the tooth. My assistant then mixed Variolink resin cement (Ivoclar Vivadent). She placed it in a needle tube syringe that I used to fill the post space just past the opening. I did not want to over fill at this point because it would make it difficult to find the post space opening. Both the resin cement and the primer/bonding agent were dual cure, so I wanted to seat the post fully as soon as possible after the Variolink was injected into the post space (Figure 8).
|Figure 9. Pre-cut post is seated in the post space.||Figure 10. Core material is added around the post and cured.|
The post was then seated fully within the post space. I then immediately syringed more of the Variolink around the remaining junction of the post and tooth. The resin cement was then cured (Figures 9 and 10). I then finished the core by building up around the post with Tetric Ceram (Ivoclar Vivadent). I will sometimes use a matrix band around the tooth to aid in building up the core. There was not enough exposed margin around the tooth to support the matrix band in this case, so I chose to sculpt Tetric Ceram composite around the post instead. Each layer was placed and then “pushed” away from the margin with a metal instrument. I prefer to have as little adjusting and trimming as possible. The prep was then adjusted occlusally, and my margins refined using the NTI F847KR-016 diamond (Axis Dental) and NSK electric handpieces. Electric handpieces cut with so much torque that it takes far less time to refine a preparation than with traditional handpieces.
|Figure 11. The post and core was completed in less than 15 minutes.|
The entire process of placing the post and core took less than 15 minutes using the materials and technique described (Figure 11).
Dr. Soileau is a general dentist from Lafayette, La. His practice focuses on restorative rehabilitation and cosmetic enhancements. He lectures nationally and internationally on the use of digital photography and computer assistance for diagnosing, treatment planning, and performing comprehensive dental procedures. He is a consultant for several technologies-based dental manufacturers and beta tests many of their products. When Dr. Soileau is not lecturing, he is a consultant to several pageant coaches throughout the country. He has judged and worked with local and national Miss USA, Miss Teen USA, Miss America, and Mrs. America contestants. Dr. Soileau is co-director of Digital Photography for GenR8TNext Digital Photography Courses and has taught digital photography at the Institute of Oral Art and Design (IOAD) in Tampa, Fla, and the Pacific Aesthetic Continuum (PAC~Live) in San Francisco. His dental and photography skills can be seen at smilesbysoileau.com. He can be reached at (337) 234-3551 or firstname.lastname@example.org.