| Abstract|| |
This article describes a technique for repair of abutment tooth which fractured during removal of a provisional restoration before bisque trial. The technique uses plastic templates to fabricate new composite core foundation for the existing crowns. This technique helps the dentist to rebuild the core in a single appointment.
Keywords: Abutment fracture, pre-existing crowns, retrofitting post and core
|How to cite this article:|
Mascarenhas K, Aras MA, Fernandes AS. Repair of fractured abutment teeth under pre-existing crowns: An alternative approach. Indian J Dent Res 2013;24:136-8
Fracture of abutment tooth/teeth is not uncommon in clinical practice,  which can be due to caries or during removal of definitive crowns or provisional restorations. Loss of coronal tooth structure often precludes the use of post and cores. Various techniques have been described in literature to replace or fabricate a post and core using an existing crown or fixed partial denture. ,, The existing crown should fit precisely on the pre-existing finish line. Therefore, when one of the abutments in a fixed partial denture (FPD) or splinted crowns fractures, then the repaired core should be placed exactly in the same location as the previous core. Slight change in core location may change the path of insertion of the FPD or splinted crowns. This article describes a procedure to repair a fractured abutment using acrylic copings to fabricate a composite core foundation in the same location as the previous core. After the fiber dowel is adapted and cemented, the composite core foundation is completed and the existing splinted crowns are cemented.
|How to cite this URL:|
Mascarenhas K, Aras MA, Fernandes AS. Repair of fractured abutment teeth under pre-existing crowns: An alternative approach. Indian J Dent Res [serial online] 2013 [cited 2019 Sep 15];24:136-8. Available from: http://www.ijdr.in/text.asp?2013/24/1/136/114924
| Case Report|| |
An endodontically treated mandibular left lateral incisor fractured at the gingival level while removal of provisional restoration during bisque trial in a 45-year-old male patient. The technique mentioned below describes the fabrication of a core precisely in the same location as the abutment tooth with pre-existing splinted crowns (mandibular left lateral and central incisor).
- Prepare the post space and cement a prefabricated light post (D. T. Light-Posts; Bisco Inc. Illinois, USA) of appropriate size and shape with a resin cement (Calibra, Dentsply, Konstanz, Germany) [Figure 1]. Verify the unobstructed seating of the ceramometal crowns after light-post installation.
- Mix an appropriate amount of putty type impression material (Aquasil; Dentsply) and place it into the intaglio surface of crowns, followed by a light body wash (Aquasil; Dentsply) to provide a silicone replica of the crowned abutment teeth. Leave a piece of material external to the crowns to allow for ease of handling [Figure 2].
- Then make an impression [Figure 3] of the putty replica in irreversible hydrocolloid (Thixotropic; Zhermack, Badia Polesine, Italy) and pour it in die stone (Dutt stone; Dutt industries, Mumbai, India).
- Apply separating media (Cold mold seal; Dentsply India, Gurgaon, India) on the dies followed by application of clear autopolymerizing resin (R and R self cure, Dentsply India) in the form of splinted copings, to fabricate a plastic template.
- Place this plastic template on the abutment teeth. Check for the unobstructed seating of the template [Figure 4]. Apply a thin layer of petroleum jelly on the intaglio surface of the template.
- Clean the tooth and dowel surfaces with water and air dry, then apply an etchant (Total etch, Ivoclar Vivadent, Schaan, Liechtenstein) to the tooth surfaces for 15 seconds, rinse, and air dry. Apply two coats of the bonding material (Prime and Bond NT, Dentsply) to the tooth surface and the coronal portion of the post, and light-polymerize for 20 seconds. Fill the inside of the plastic template with dual-polymerizing core foundation composite (Bis-Core; Bisco Inc. Schaumburg, Illinois, USA). Place the matrices over the posts and seat the crowns using finger pressure. Initially polymerize the excess composite material with a light-polymerizing unit (QHL 75 Curing light, Dentsply) for 5 seconds and remove the excess material with a probe [Figure 5]. After removing the crowns, light-polymerize the core foundation composite for 40 seconds.
- Section and remove the plastic templates. After removing the excess material, evaluate the fit of the crowns on the fabricated core foundations. Finish the core surface with a fine finishing bur [Figure 6] and [Figure 7].
|Figure 7: Definitive restoration on mandibular left lateral and central incisor|
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Alternatively, the plastic template can be fabricated if the definitive impression or master cast is preserved. If the definitive impression is preserved, then it is re-poured to obtain a cast. The plastic template is fabricated in autopolymerizing resin, following the application of separating media.
The technique mentioned here is simple, economical, and less time consuming as it can be done in a single appointment. It helps to repair the core precisely in the same location as the abutment tooth.
| Discussion|| |
The amount of tooth structure that remains after endodontic therapy and post preparation appears to be of major importance, as the residual dentin helps in incorporating a ferrule. Only few studies have demonstrated that the presence of tooth structure coronal to the finish line does not enhance fracture resistance. ,
Glass and quartz-fiber reinforced dowel systems have elastic moduli comparable to that of dentin.  These posts can be bonded to tooth structure with resin luting agents. It has been postulated that this allows the formation of a secondary monoblock,  where tooth, post, core, and crown function as a single cohesive unit. Considering the literature, it is important to have a ferrule for any post, core, and crown restoration.  When the abutment fractures at the gingival margin during the course of treatment, the existing restoration will not have ferrule effect. Therefore, more amount of tooth structure coronal to the finish increases the longevity of the definitive restoration.
The advantage of this technique is that the procedure for reproduction of internal contours of a pre-existing crown does not depend on the availability of the die of the original preparation,  as described in earlier articles. ,, Sufficient amount of cement thickness was ensured by the finishing procedures of the core buildup.
| Conclusion|| |
The use of translucent quartz post and core composites allows the clinician to quickly create an post and core in a single appointment, which is well adapted to root canal preparation. The plastic template helps the clinician to build the core precisely in the same location, which helps in seating of the crowns without many adjustments.
| References|| |
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Department of Prosthodontics, Goa Dental College and Hospital, Bambolim, Goa
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]