Management of subgingival fracture by an esthetic approach.

Extrusion of fractured anterior teeth with fracture line extending subgingivally requires exposure of sound tooth structure. Orthodontic extrusion is the preferred method of choice. Conventional orthodontic appliance is usually unesthetic because of exposure of brackets. This case report describes an esthetic management of such a tooth with a lingually placed orthodontic appliance which also allows placement of a labial composite resin laminate so as to restore esthetics at the earliest. This was followed by a post-endodontic restoration. This approach enabled us to establish not only to a long-term restorative success, but also an immediate replacement of esthetics so that the patient is able to confidently smile during the course of treatment also.

INTRODUCTION

Subgingival fracture of anterior tooth causes not only an esthetic and functional breakdown but also a psychological breakdown. Treatment of subgingival fracture of anterior tooth often requires a multidisciplinary approach.[1] A combination of endodontic, periodontal, orthodontic and restorative procedures may be required. Periodontal or orthodontic intervention is required to expose a sound tooth supragingival tooth structure so that a crown ferrule is obtained. A good crown ferrule is mandatory for a long-term restorative success. This procedure leaves us with various options. They are

crown lengthening,

surgical extrusion and

orthodontic extrusion.

Of the above-mentioned options, orthodontic extrusion has been shown to be a better option since it does not alter the biological width or the position of the gingival margin of the tooth involved.

Orthodontic extrusion is a biological way of exposure of sound tooth structure and therefore requires a prolonged treatment,[23] as 2 mm subgingival fracture will require an extrusion of about 4 mm.[24] This 4 mm would be required so that there is a 2 mm sound supragingival tooth structure. This amount of extrusion would normally take about 2–4 months time. More than the duration of the extrusion, it is the difficulty to provide esthetics in the anterior region during the course of treatment which is an area of concern. Loss of esthetics is due to two reasons. One, the fractured tooth is not reconstructed and two, the exposure of the orthodontic brackets during a smile.

In this case, a different clinical technique has been employed using a multidisciplinary approach in treating a subgingival fracture while maintaining the esthetics to an extent that the patient is also psychologically comfortable during the course of treatment.

CASE REPORT

A 35-year-old male patient reported to Department of Conservative Dentistry and Endodontics with a fracture of tooth #21 due to fall from a motorcycle on the previous day. Past dental history revealed that #21 was root canal treated 2 months back and the patient had not been for the crown. On clinical examination, the fracture line was oblique, with the fracture extending 1—2 mm supragingival on the labial surface and up to 2 mm subgingival on the proximal and palatal side [Figure 1a and b]. Radiographic examination revealed that the obturation was satisfactory and there was no associated fracture and the root, and lamina dura remained intact [Figure 2a]. The patient was very keen on saving the tooth and requested establishment of esthetics at the earliest.

Figure 1

(a) Pre-op view of fractured #21 (labial view). (b) Pre-op view of fractured #21 (palatal view). (c) Lingual orthodontic appliance bonded to #21. (d) After extrusion with composite resin veneer, showing the orthodontic bracket. (e) Cast post and core in #21. (f) Crown cemented in #21

Figure 2

(a) Pre-op IOPA radiograph. (b) IOPA radiograph after extrusion

A tentative treatment plan of endodontic treatment followed by lingual orthodontic extrusion and a crown with a dowel and core was planned.

As the patient requested maintenance of esthetics during the course of treatment, orthodontic extrusion was planned with lingual orthodontics so that the brackets are not exposed. Since the tooth had a satisfactory obturation, the entrance filling alone was changed to composite resin so that the bonding of the orthodontic bracket was on the resin and not on Glass ionomer cement (GIC). The button brackets were fixed on the lingual surface of the involved tooth, 2 mm cervical to the usual position, and tied with 0.012″NiTi arch wire [Figure 1c]. Then, a provisional buildup of the tooth with composite resin was done in the form of a laminate to restore esthetics. As advised by various authors, a force of 0.2–0.3 N was used.[45] Patient was recalled every week to judge the amount of extrusion. The desired extrusion of 4 mm required about 6 weeks. The extrusion was also evident on intra oral periapical (IOPA) radiograph [Figure 2b].

After the desired amount of extrusion as observed in Figure 1d, surgical re-contouring of the labial gingival margin followed by supracrestal fibrotomy was done. The orthodontic appliance was left passive for 2 months to stabilize the achieved extrusion. Patient was recalled after 2 months and the orthodontic appliance was debanded. The provisional composite buildup was then removed and the tooth was prepared for a post and core. A direct wax pattern was made for a post and core and was sent to the laboratory for fabrication. A chairside provisional crown was made and the patient was recalled after a day for cast post and core cementation. The cast post was cemented with resin cement [Figure 1e] and a new provisional crown was made. Supracrestal fibrotomy was repeated and the provisional crown was cemented. After 3 months, an impression was made and zirconia layered with e-max ceramic crown was cemented [Figure 1f].

DISCUSSION

Forced orthodontic extrusion can be defined as a movement of vertical translation in a coronal direction obtained through the application of continuous light forces.[6] Orthodontic extrusion of a subgingival fracture was reported as early as 1973 by Heithersay. Thereafter, there have been many reports of management of subgingival fracture by orthodontic extrusion [Table 1]. Most of the cases of extrusion of central incisor were managed with a labially placed, either removable or fixed orthodontic appliance which could be a compromise on anterior esthetics. Such exposure of the appliance along with the fractured tooth during the course of treatment can be avoided if lingually placed orthodontic appliance can be used, which is evident in Figure 1d.

Table 1

Case reports of orthodontic extrusion of subgingival fracture of tooth

Lingual orthodontic extrusion of a central incisor had been attempted to improve and develop the implant site.[7] In a case reported by palone et al., they could not restore the tooth with a prosthetic crown as the crown–root ratio was not favorable. Lingual placement of brackets not only prevents the display of the appliance but also allows us to reconstruct the tooth for better esthetics. The laminate was built 1 mm short when compared to the contralateral tooth to prevent dislodgment upon protrusive movement as the tooth extrudes.

In the present case, we also limited our forced eruption within the maximum limit of 5 mm[8] to avoid relapse and to maintain proper crown–root ratio for a favorable prosthetic restoration.[9] After the extrusion, it was observed that the gingival margin had migrated coronally.[10] Gingival recontouring was done to reposition the gingival margin in line with the contralateral tooth for good esthetics.[11] A circumferential supracrestal fibrotomy was also performed to prevent reverse movement of the root (i.e.) intrusion to the earlier position).[1113] Further, it was repeated 4 weeks later as suggested by Heda et al.[14] Retention period to prevent relapse has also been suggested. Although the recommendation varies from 1 week to about 1 month per millimeter of extrusion,[15] in this case, a period of 60 days was given.[15] Alternatively, an over-extrusion was also suggested,[16] but this was not done because it could delay the final crown as we have to wait till the relapse is over and is unpredictable.

Extrusion was done such that there is an exposure of 2 mm supragingival tooth structure. This enables us to provide a circumferential core ferrule of 1 mm and another 1 mm of crown ferrule which is mandatory for proper stress distribution and prevention of microleakage and failure of restoration. Care was taken not to compromise on the crown–root ratio of at least 1:1 for a good long-term prognosis.[17] A cast post and core was preferred as it has a good long-term prognosis[18] and improves the fracture resistance of endodontically treated tooth.[19]

Of the other options available for exposing the sound natural tooth structure, crown lengthening by gingivoplasty and reshaping the crestal alveolar bone can necessitate removal of supporting bone from the adjacent teeth in order to achieve a smooth flow from tooth to tooth.[17] This would not only result in an esthetic problem which may be difficult to correct but also some additional bone resorption that causes unfavorable crown–root ratio.[9] Attempts to expose the fracture line by alveolar ridge recontouring of the involved tooth alone may compromise esthetics, especially in the anterior region of the dental arch.[2021]

Another option is surgical extrusion as suggested by Caliskan et al.[22] This procedure in not without a risk of poor long-term esthetic problem.[23] Surgical extrusion may also require more motivation to obtain consent from the patient.

Thus, in this case, apart from achieving the goal of extrusion for crown ferrule and long-term restorative success, we have tried to achieve esthetics during the course of treatment also, so that the extrusion is not only in a biological way but also ensures a psychological comfort as the patient need not compromise on anterior esthetics.